U.S. patent application number 13/474101 was filed with the patent office on 2012-12-20 for compositions and methods for modulating lymphocyte activity.
This patent application is currently assigned to THE WASHINGTON UNIVERSITY. Invention is credited to Michelle A. Hurchla Pyles, Kenneth M. Murphy, Theresa L. Murphy, John R. Sedy, Norihiko Watanabe, Jianfei Yang.
Application Number | 20120322986 13/474101 |
Document ID | / |
Family ID | 44647736 |
Filed Date | 2012-12-20 |
United States Patent
Application |
20120322986 |
Kind Code |
A1 |
Murphy; Kenneth M. ; et
al. |
December 20, 2012 |
COMPOSITIONS AND METHODS FOR MODULATING LYMPHOCYTE ACTIVITY
Abstract
The present invention provides a novel lymphocyte inhibitory
receptor termed BTLA which is expressed on both T and B cells, and
identifies HVEM as interacting with BTLA. Methods and compositions
for modulating BTLA-mediated signaling and interfering with the
interaction of BTLA and HVEM for therapeutic, diagnostic and
research purposes are also provided.
Inventors: |
Murphy; Kenneth M.; (St.
Louis, MO) ; Murphy; Theresa L.; (St. Louis, MO)
; Sedy; John R.; (St. Louis, MO) ; Hurchla Pyles;
Michelle A.; (St. Louis, MO) ; Watanabe;
Norihiko; (St. Louis, MO) ; Yang; Jianfei;
(St. Louis, MO) |
Assignee: |
THE WASHINGTON UNIVERSITY
St. Louis
MO
|
Family ID: |
44647736 |
Appl. No.: |
13/474101 |
Filed: |
May 17, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12977562 |
Dec 23, 2010 |
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13474101 |
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11875537 |
Oct 19, 2007 |
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12977562 |
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10600997 |
Jun 20, 2003 |
7304149 |
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11875537 |
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11719356 |
Dec 12, 2007 |
8188232 |
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PCT/US2005/041446 |
Nov 15, 2005 |
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12977562 |
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60390653 |
Jun 20, 2002 |
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60438593 |
Jan 6, 2003 |
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60628474 |
Nov 15, 2004 |
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Current U.S.
Class: |
530/387.9 ;
530/388.22; 530/389.6 |
Current CPC
Class: |
C07K 2317/76 20130101;
C07K 2317/34 20130101; C07K 14/70521 20130101; C07K 2319/00
20130101; C07K 16/2818 20130101; C07K 2319/30 20130101; A61P 35/00
20180101; A61P 37/02 20180101; C07K 14/70532 20130101; A61K
2039/505 20130101 |
Class at
Publication: |
530/387.9 ;
530/389.6; 530/388.22 |
International
Class: |
C07K 16/28 20060101
C07K016/28 |
Claims
1. An antibody capable of specifically binding to a protein having
an amino acid sequence set forth in SEQ ID NO:8, wherein the
antibody is capable of reducing binding of a BTLA protein to an
HVEM protein.
2. An antibody capable of specifically binding to a protein having
an amino acid sequence set forth in SEQ ID NO:8, wherein the
antibody is capable of reducing binding of a BTLA Ig domain to an
HVEM CRD1 domain.
3. The antibody of claim 2, wherein the BTLA Ig domain comprises
amino acids 43 to 134 of SEQ ID NO:8.
4. An anti-BTLA antibody capable of specifically binding to a BTLA
protein, wherein the antibody is capable of reducing binding of the
BTLA protein to an HVEM protein.
5. An antibody capable of specifically binding to a protein having
at least about 95% identity to the amino acid sequence set forth in
SEQ ID NO:8, wherein the antibody is capable of reducing binding of
a BTLA protein to an HVEM protein.
6. The antibody of claim 5, wherein the protein has at least about
98% identity to the amino acid sequence set forth in SEQ ID
NO:8.
7. An antibody capable of specifically binding to a protein having
at least about 95% identity to the amino acid sequence set forth in
SEQ ID NO:8, wherein the antibody is capable of reducing binding of
a BTLA Ig domain to an HVEM CRD1 domain.
8. The antibody of claim 7, wherein the protein has at least about
98% identity to the amino acid sequence set forth in SEQ ID
NO:8.
9. The antibody of claim 7, wherein the BTLA Ig domain comprises
amino acids 43 to 134 of SEQ ID NO:8.
10. An antibody capable of specifically binding to a protein having
an amino acid sequence set forth in SEQ ID NO:6, wherein the
antibody is capable of reducing binding of a BTLA protein to an
HVEM protein.
11. An antibody capable of specifically binding to a protein having
an amino acid sequence set forth in SEQ ID NO:6, wherein the
antibody is capable of reducing binding of a BTLA Ig domain to an
HVEM CRD1 domain.
12. The antibody of claim 11, wherein the BTLA Ig domain comprises
amino acids 43 to 134 of SEQ ID NO:6.
13. A BTLA antibody, wherein said antibody is capable of
specifically binding to a BTLA protein, and wherein said antibody
is capable of reducing the binding of said BTLA protein to an HVEM
protein.
14. The BTLA antibody according to claim 13, wherein said antibody
is capable of specifically binding to a mouse BTLA protein.
15. The BTLA antibody according to claim 13, wherein said antibody
is capable of specifically binding to a human BTLA protein.
16. The BTLA antibody according to claim 13, wherein said BTLA
protein and said HVEM protein are on the surface of a first cell
and a second cell, respectively.
17. The BTLA antibody according to claim 13, wherein said BTLA
protein is a recombinantly produced tetramer.
18. The BTLA antibody according to claim 13, wherein said antibody
is capable of binding toward the DEBA face of the Ig fold of said
BTLA protein.
19. The BTLA antibody according to claim 13, wherein said antibody
is capable of binding to a region of the Ig domain of said BTLA
protein, which region is capable of binding to the complementarity
determining region (CRD) 1 domain of said HVEM protein.
20. The BTLA antibody according to claim 13, wherein said antibody
binds to an epitope comprising one or more residues selected from
the group consisting of V42, Q43, L44, R55, Q63, Q102, and C85 of
SEQ ID NO:1.
21. The BTLA antibody according to claim 13, wherein said antibody
binds to an epitope comprising one or more residues selected from
the group consisting of V36, Q37, L38, L49, E57, C79, K93, and S96
in the human BTLA sequence set forth in SEQ ID NO:2.
22. The BTLA antibody according to claim 13, wherein said antibody
is capable of binding to a polypeptide selected from the group
consisting of the amino acid sequences set forth by residues 37-47,
39-49, 41-49, 50-60, 58-68, 80-90, 97-107, 50-90, 55-85, 58-90,
63-85, 80-107, 85-102, 127-137, 55-102, 50-107, and 41-137 of SEQ
ID NO:1.
23. The BTLA antibody according to claim 13, wherein said antibody
is capable of binding to a polypeptide selected from the group
consisting of the amino acid sequences set forth by residues 31-41,
32-42, 35-43, 44-54, 52-62, 74-84, 88-98, 44-84, 49-79, 52-84,
57-79, 74-98, 79-93, 118-128, 49-93, 44-98, 35-98, and 35-128 of
the human BTLA isoform set forth in SEQ ID NO:2.
24. The BTLA antibody according to claim 13, wherein said antibody
is a monoclonal antibody.
25. The BTLA antibody according to claim 13, wherein said antibody
is a human antibody.
26. A pharmaceutical composition, comprising a BTLA antibody
according to claim 13.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 12/977,562, filed Dec. 23, 2010, which is a continuation in
part of U.S. application Ser. No. 11/875,537, filed Oct. 19, 2007,
which is a divisional of U.S. application Ser. No. 10/600,997,
filed Jun. 20, 2003, now U.S. Pat. No. 7,304,149, which claims
priority to U.S. Provisional Patent Application Ser. No.
60/390,653, filed Jun. 20, 2002, and to U.S. Provisional Patent
Application Ser. No. 60/438,593, filed Jan. 6, 2003, and U.S.
application Ser. No. 12/977,562, filed Dec. 23, 2010, is a
continuation in part of U.S. application Ser. No. 11/719,356, filed
Dec. 12, 2007, which is a US National of PCT/US2005/041446, filed
Nov. 15, 2005, which claims priority to U.S. Provisional Patent
Application Ser. No. 60/628,474, filed Nov. 15, 2004, the
disclosures of each of which are expressly incorporated herein, in
their entirety, by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to immunomodulatory
compositions and methods, and in particular, to novel lymphocyte
regulatory molecules as well as compositions and methods exploiting
the same for therapeutic, diagnostic and research purposes.
BACKGROUND OF THE INVENTION
[0003] Positive and negative costimulatory signals play critical
roles in the modulation of T cell activity, and the molecules that
mediate these signals have proven to be effective targets for
immunomodulatory agents. Positive costimulation, in addition to T
cell receptor (TCR) engagement, is required for optimal activation
of naive T cells, whereas negative costimulation is believed to be
required for the acquisition of immunologic tolerance to self, as
well as the termination of effector T cell functions. Upon
interaction with B7.1 or B7.2 on the surface of antigen-presenting
cells (APC), CD28, the prototypic T cell costimulatory molecule,
emits signals that promote T cell proliferation and differentiation
in response to TCR engagement, while the CD28 homologue cytotoxic T
lymphocyte antigen-4 (CTLA-4) mediates inhibition of T cell
proliferation and effector functions (Chambers et al., Ann. Rev.
Immunol., 19:565-594, 2001; Egen et al., Nature Immunol.,
3:611-618, 2002).
[0004] Agents capable of modulating positive and negative
costimulatory signals are highly desirable for use in the
modulation of adaptive immune responses. Many autoimmune disorders
are known to involve autoreactive T cells and autoantibodies.
Agents that are capable of inhibiting the activation of lymphocytes
that are specific for self antigens are desirable. Similarly, under
certain conditions it is desirable to inhibit normal immune
responses to antigen. For example, the suppression of normal immune
responses in a patient receiving a transplant is desirable, and
agents that exhibit such immunosuppressive activity are highly
desirable.
[0005] Conversely, many cancer immunotherapies, such as adoptive
immunotherapy, expand tumor-specific T cell populations and direct
them to attack and kill tumor cells (Dudley et al., Science
298:850-854, 2002; Pardoll, Nature Biotech., 20:1207-1208, 2002;
Egen et al., Nature Immunol., 3:611-618, 2002). Agents capable of
augmenting tumor attack are highly desirable.
[0006] In addition, immune responses to many different antigens
(e.g., microbial antigens or tumor antigens), while detectable, are
frequently of insufficient magnitude to afford protection against a
disease process. Agents capable of promoting and/or prolonging the
activation (delaying termination) of lymphocytes that are specific
for such antigens are highly desirable.
[0007] Costimulatory signals, particularly positive costimulatory
signals, also play a role in the modulation of B cell activity. For
example, B cell activation and the survival of germinal center B
cells require T cell-derived signals in addition to stimulation by
antigen. CD40 ligand present on the surface of helper T cells
interacts with CD40 on the surface of B cells and provides such a
positive costimulatory signal to B cells.
[0008] Herpes virus entry mediator ("HVEM"), a member of the
TNF/NGF receptor family, is another positive costimulatory receptor
that additionally mediates the entry of herpes simplex virus (HSV)
into cells (Montgomery et al., Cell. 1996 Nov. 1; 87 (3):427-36).
Anti-HVEM antibodies and a soluble hybrid protein containing the
HVEM ectodomain have been shown to inhibit such HVEM-dependent
viral entry. HSV-1 glycoprotein D (gD), a structural component of
the HSV envelope, binds to HVEM to facilitate viral entry (Whitbeck
et al., J. Virol. 1997 August; 71 (8):6083-93). HVEM binds two
cellular ligands, secreted lymphotoxin alpha and LIGHT (Mauri et
al., Immunity. 1998 January; 8(1):21-30). HSV-1 gD inhibits the
interaction of HVEM with LIGHT. Additionally, targeted disruption
of LIGHT causes immunomodulatory defects (Scheu et al., J. Exp.
Med., 195:1613-1624, 2002). Additionally, a phage-derived peptide
BP-2 reportedly binds to HVEM and can compete with HSV-1 gD (Carfi
et al., Mol. Cell. 8:169-179, 2001; Sarrias et al., Mol. Immunol.,
37:665-673, 2000).
SUMMARY OF THE INVENTION
[0009] One aspect of the present invention encompasses an antibody
capable of specifically binding to a protein having an amino acid
sequence set forth in SEQ ID NO:8, wherein the antibody is capable
of reducing binding of a BTLA protein to an HVEM protein.
[0010] Another aspect of the invention encompass an antibody
capable of specifically binding to a protein having an amino acid
sequence set forth in SEQ ID NO:8, wherein the antibody is capable
of reducing binding of a BTLA Ig domain to an HVEM CRD1 domain.
[0011] Yet another aspect of the invention encompasses an anti-BTLA
antibody capable of specifically binding to a BTLA protein, wherein
the antibody is capable of reducing binding of the BTLA protein to
an HVEM protein.
[0012] Still another aspect of the invention encompasses an
antibody capable of specifically binding to a protein having at
least about 95% identity to the amino acid sequence set forth in
SEQ ID NO:8, wherein the antibody is capable of reducing binding of
a BTLA protein to an HVEM protein.
[0013] A further aspect of the invention encompasses an antibody
capable of specifically binding to a protein having at least about
95% identity to the amino acid sequence set forth in SEQ ID NO:8,
wherein the antibody is capable of reducing binding of a BTLA Ig
domain to an HVEM CRD1 domain.
[0014] Yet a further aspect of the invention encompasses an
antibody capable of specifically binding to a protein having an
amino acid sequence set forth in SEQ ID NO:6, wherein the antibody
is capable of reducing binding of a BTLA protein to an HVEM
protein.
[0015] Still a further aspect of the invention encompasses an
antibody capable of specifically binding to a protein having an
amino acid sequence set forth in SEQ ID NO:6, wherein the antibody
is capable of reducing binding of a BTLA Ig domain to an HVEM CRD1
domain.
[0016] Other aspects and iterations of the invention are described
more thoroughly below.
BRIEF DESCRIPTION OF THE FIGURES
[0017] FIG. 1 shows the amino acid sequences of mouse B7x protein
(SEQ ID NO: 1) and human B7x protein (SEQ ID NO: 2).
[0018] FIG. 2 shows the nucleotide sequence of mouse B7x nucleic
acid (SEQ ID NO:3) encoding mouse B7x protein.
[0019] FIG. 3 shows the nucleotide sequence of human B7x nucleic
acid (SEQ ID NO:4) encoding human B7x protein.
[0020] FIG. 4 shows amino acid sequence alignment of B7x with other
mouse B7 family members obtained using the ClustalW with BLOSUM
Series of MacVector 7.0. Conserved cysteine residues are marked
with an asterisk. Identical amino acids are highlighted in black
and similar residues in gray shading (SEQ ID NOS:57-62).
[0021] FIG. 5 shows a comparison of human B7x with mouse B7x.
Predicted signal peptide, Ig V-like and C-like domains, the
transmembrane region and cytoplasmic tail for B7x are indicated.
Identical amino acids are highlighted in black and similar residues
in gray shading. The potential N-glycosylation sites are
arrowed.
[0022] FIG. 6 shows a phylogenetic tree of the B7 family from mouse
and human generated by PAUP (4.0b10) using sequence alignment by
removal of significant inserts and trimming C- and N-terminal
extensions. All branches of the tree were supported by Bootstrap
confidence values of >50% after 100 replicates. Numbers show the
percentage of bootstrap support for each Glade.
[0023] FIG. 7 shows Northern blot analysis of human poly(A) RNA
(left panel) and mouse poly(A) RNA (right panel) from a variety of
tissues with B7x and actin cDNA probes.
[0024] FIG. 8 shows RT-PCR analysis of B7x mRNA expression in a
variety of mouse tissues and immune cells. (A) Real timePCR was
performed on cDNA from multiple mouse tissues. cDNA from the
Clontech Mouse MTC panel I was used as well as cDNA made from
tissues dissected out of 2 C57/BL6 mice. The results shown are the
average and standard deviation between the 3 mouse cDNA samples.
(B) Real time PCR was performed on CD11c+ Denndritic cells, B cells
and T cells that were purified from the spleen and compared to the
whole spleen. Thioglycolate induced macrophages were purified by
overnight adherence and removal of non-adherent cells. The results
shown represents the average and standard deviation between 4-10
individual mouse samples.
[0025] FIG. 9 shows RT-PCR analysis of B7x mRNA expression in a
variety of tumor cells. Lanes: 1: EL4, 2:B16BL6, 3: B16F10, 4:
Lewis lung carcinoma, 5: TRAMP C2, 6:MC38, 7: SAI/N, 8: SM1, 9:
C6VL, 10: DC2.4, 11: CHO cells, 12: CHO cells transfected with B7x
gene, 13: no DNA control.
[0026] FIG. 10 shows activated CD4+ T cells stained with B7xIg
fusion protein (black line) or control mouse IgG1 (gray line).
[0027] FIG. 11 shows activated CD8+ T cells stained with B7x-Ig
fusion protein (black line) or control mouse IgG1 (gray line).
[0028] FIG. 12 shows 293 cells (shaded histograms), and transfected
293 cells expressing CD28, ICOS, or PD-1 (open histograms), and
DT320 cells expressing CTLA-4 (open histograms), stained with B7xIg
fusion protein or control antibody (anti-CD28, anti-ICOS,
anti-PD-1, anti-CTLA-4).
[0029] FIGS. 13A and 13B show T cells purified from wildtype and
BTLA-/- mice that are stained with B7x-Ig fusion protein or B7h-Ig
fusion protein as indicated.
[0030] FIG. 14 is a series of graphs representing the results from
experiments in which murine T cells, and T cell subsets (CD4+ and
CD8+) were stimulated with plate-bound anti-CD3 and varied amounts
of plate-bound B7x-Ig () or control Ig ( ). IL-2 production and
.sup.3H-thymidine incorporation were measured.
[0031] FIG. 15 is a series of graphs representing the results from
experiments in which purified T cells were stimulated with varied
amounts of plate-bound anti-CD3 and CHO transfectants expressing
GFP ( ), B7.2 (.smallcircle.) or B7x ( The production of IL-10,
IL-4, IFN-.gamma., and IL-2, and the incorporation of and
.sup.3H-thymidine were measured.
[0032] FIG. 16 is a series of graphs representing the results from
experiments in which murine T cells were stimulated with varied
amounts of plate-bound anti-CD3 and CHO transfectants expressing
GFP ( ), B7.2 (.smallcircle.) or B7x/B7.2 (). The production of
IL-10, IL-4, IFN-.gamma., and IL-2, and the incorporation of and
.sup.3H-thymidine were measured.
[0033] FIG. 17 is a series of plots showing flow cytometry analysis
of CD4+ T cells. Cells were labeled with CSFE and stimulated with
or without plate-bound anti-CD3 (0.25 mg/ml) and CHO transfectants
expressing GFP or B7x. Percentages refer to fraction of cells in
the non-dividing peak or divided more than two times.
[0034] FIG. 18 is a series of plots showing flow cytometry analysis
flow cytometry analysis of CD8+ T cells. Cells were labeled with
CSFE and stimulated with or without plate-bound anti-CD3 (0.25
mg/ml) and CHO transfectants expressing GFP or B7x. Percentages
refer to fraction of cells in the non-dividing peak or divided more
than two times.
[0035] FIG. 19 shows the amino acid sequences of a mouse BTLA
protein (SEQ ID NO: 5) and a human BTLA protein (SEQ ID NO: 6). The
mouse and human sequences are aligned, and spaces are shown as ( )
for optimal comparison. The signal peptide and the transmembrane
region are underlined. Potential N-linked glycosylation sites (-)
and cysteine residues ( ) predicted to participate in Ig domain
disulfide bonding are indicated with markings above the residues.
The conserved sequences around putative tyrosine-based signaling
motifs are boxed.
[0036] FIG. 20 shows the exon/intron organization of mouse and
human BTLA genes. Filled boxes indicate coding sequence within
exons, and unfilled boxes indicate 3' and 5' untranslated regions.
The amino acid number encoded by each exon is indicated below.
[0037] FIG. 21 shows the predicted structural regions of BTLA. Full
length murine BTLA (MBTLA) and a minor splice variant (BTLAs)
lacking exon 2 and deleting the Ig domain, are shown. Roman
numerals shown below the figure indicate the exon from which the
predicted region is derived. In parentheses is indicated the
theoretical molecular weight of the predicted protein before
addition of further modifications.
[0038] FIG. 22 shows Northern blot analyses of the expression of
BTLA. 10 mg of tissue or cellular RNA, or total RNA from the
indicated cells, probed with a full-length BTLA or GAPDH cDNA
probe.
[0039] FIG. 23: BTLA is a transmembrane, glycosylated protein that
is inducibly tyrosine phosphorylated. (A) FACScalibur analysis of
BJAB cells infected with myc-tagged BTLA, Acyt BTLA, BTLAs and
empty vector, and stained with anti-myc mAb. (B) Anti-myc Western
blot. BJAB cells were infected with myc-tagged mouse BTLA or
myc-tagged human BTLA, lysed, and anti-myc immunoprecipitates were
treated with peptide N-glycosidase F, where indicated. (C)
Anti-phosphotyrosine Western blot. BJAB cells infected with
myc-tagged BTLA (WT) or single tyrosine mutant myc-tagged BTLA
(Y226F, Y257F, Y282F) were incubated in the absence or presence of
pervanadate (VO.sub.4), BTLA proteins were immunoprecipitated with
anti-myc, and immunoprecipitates were probed with
anti-phosphotyrosine. (D) Anti-phosphotyrosine Western blot. BJAB
cells infected with myc-tagged BTLA (WT) or with double or triple
tyrosine mutant myc-tagged BTLA (as indicated) were incubated in
the absence or presence of pervanadate (VO.sub.4), BTLA proteins
were immunoprecipitated with anti-myc, and immunoprecipitates were
probed with anti-phosphotyrosine.
[0040] FIG. 24 Inducible association of BTLA with SHP-2. (A)
Anti-phosphotyrosine and anti-SHP-2 Western blots. DO11.10 cells
with empty vector (GFP-RV), or expressing BTLAs with extracellular
myc epitope (myc-BTLAs). Cells were incubated with anti-CD3,
anti-myc, or pervanadate as indicated. Cells were treated with goat
anti-mouse IgG (GaM) for indicated time. Anti-myc immunoprecipitate
was probed with anti-phosphotyrosine and anti-SHP-2 antibody. (B)
Anti-phosphotyrosine Western blot. Cells and treatment as described
in (A) and indicated. (C) Anti-phosphotyrosine, anti-SHP-1 and
anti-SHP-2 Western blots. Cells as described in (A), incubated in
the absence (-) or presence (+) of pervanadate. Anti-myc
immunoprecipitates and whole cell lysates probed with
anti-phosphotyrosine, anti-SHP-1, and anti-SHP-2 antibodies. (D)
Anti-myc and anti-SHP-2 Western blots. Cells as described in (A),
incubated in the absence (-) or presence (+) of pervanadate.
Anti-SHP-2 immunoprecipitates and whole cell lysates probed with
anti-myc and anti-SHP-2 antibodies. (E) Anti-myc, anti-SHP-2 and
anti-phosphotyrosine Western blots. Jurkat T cells with GFP-RV, or
expressing a full length human BTLA containing an N-terminal myc
epitope. Cells were treated with pervanadate as indicated. Anti-myc
and anti-SHP-2 immunoprecipitates were probed with anti-myc,
anti-SHP-2 and anti-phosphotyrosine. (F) DO11.10 cells expressing
control vector (GFP-RV), myc-BTLAs (short isoform), or myc-BTLA
were stimulated with anti-CD3 plus the indicated amounts of
anti-myc, and IL-2 production was determined by ELISA. (G) DO11.10
cells expressing control vector (GFP-RV), myc-BTLAs (short
isoform), or myc-BTLA were stimulated with PMA plus ionomycin as
indicated.
[0041] FIG. 25 (A) The scheme used to generate BTLA-/- mice. (B)
Southern blot. BgIII-digested tail DNA hybridized with probe B. (C)
Northern blot. RNA from splenocytes probed with full length mouse
BTLA cDNA probe, and GAPDH probe for control. (D) Th1 proliferation
assay. Resting Th1 cells from DO01.10+/BTLA+/+(+/+) or
DO11.10+/BTLA-/-(-/-) mice were incubated with CD8+ or CD8- DCs
with or without OVA323-339 peptide, and [.sup.3H] thymidine
incorporation was measured.
[0042] FIG. 26 Increased EAE susceptibility in BTLA-/- mice. (A)
Clinical scoring of WT mice injected with 2 .mu.g, 10 .mu.g, and 50
.mu.g in incomplete Freund's adjuvant. Clinical scores: score 0,
normal mouse, no overt signs of disease; 1, limp tail or hind limb
weakness, but not both; 2, limp tail or hind limb weakness; 3,
partial hind limb paralysis; 4, complete hind limb paralysis; 5,
moribund state, death by EAE, sacrifice for humane reasons). (B)
Clinical scoring of WT and BTLA-/- mice injected with suboptimal
dose (2 .mu.g) of MOG peptide.
[0043] FIG. 27: Normal lymphocyte development in BTLA-/- mice. FACS
analysis of thymus, spleen and bone marrow cells from BTLA+/+ and
BTLA-/- littermates stained with (A1) CD4-PE, CD8-FITC, and
CD3c-biotin/SA-Cychrome; (A2) B220-PE,
.alpha.IgM-biotin/SA-Cychrome, .alpha.lgD-FITC and CD43-FITC. (B)
FACS analysis of splenocytes stained .gamma..delta.-TCR-FITC,
DX5-FITC (pan NK), Gr-1-biotin/SA-Cychrome,
Mac-1-biotin/SA-Cychrome, and anti-cKit-biotin/SA-Cychrome.
Histograms overlayed for each marker (black line; +/+, red line;
-/-).
[0044] FIG. 28 shows the sequences of human BTLA nucleic acid (SEQ
ID NO:7) and encoded human BTLA protein (SEQ ID NO:8). The nucleic
acid and amino acid sequences are found at Genbank accession
numbers AY293286.1 and AAP44003.1, respectively.
[0045] FIG. 29 shows the sequences of mouse BTLA nucleic acid (SEQ
ID NO:9) and encoded mouse BTLA protein (SEQ ID NO:10). The nucleic
acid and amino acid sequences are found at Genbank accession
numbers AY293285.1 and AAP44002.1, respectively.
[0046] FIG. 30 (A-C) shows the BTLA allelic variation between a
number of mouse strains (SEQ ID NOS: 11-27, from top to
bottom).
[0047] FIG. 31: BTLA interacts with an orphan B7, B7x. (A) Spleen
and lymph node cells from BTLA wild-type and BTLA-deficient
DO11.10+ TCR transgenic mice were collected and stimulated with 0.3
.mu.M OVA peptide, 10 U/ml of IL-12 and neutralizing antibodies to
IL-4, and assayed for Ig fusion binding after 4 d. Cells were
stained with anti-CD4-FITC. Left, cells were stained with a human
IgG1 antibody as a negative control (filled) or with a B7x-Ig
fusion protein (open), followed by goat anti-human IgG-PE. Right,
cells were unstained (filled) or stained with B7h-Ig (open),
followed by biotinylated anti-Myc (murine IgG1 isotype) and
streptavidin-PE. Anti-Myc was used as a negative control for the
B7h-Ig fusion protein. (B, C) TH1 cell lines derived from BTLA
wild-type and BTLA-deficient DO11.10+ mice were stimulated as
above, collected on day 3, and assayed for binding to Ig fusion
proteins. All cells were stained with anti-CD4-FITC. In B, Cells
were stained with a human IgG1 antibody (filled) or with B7.1-Ig,
B7.2-Ig, PD-L1-Ig and PD-L2-Ig fusion proteins (open), followed by
goat anti-human Fc.gamma. F(ab)2-PE. In c, Cells were stained with
a hamster IgG2-PE as a negative control (filled) or with
anti-PD-1-PE. Histograms are gated on CD4+ cells.
[0048] FIG. 32: In vitro responses of BTLA-deficient lymphocytes. T
and B cell from wild-type (WT) or BTLA-deficient (KO) mice were
purified by cell sorting using anti-CD4-FITC, anti-CD8.alpha.-FITC
or anti-B220-PE. Cells were stimulated with the indicated final
concentrations of plate-bound anti-IgM, LPS, concanavalin A or
plate-bound anti-CD3c. Cell proliferation was measured by pulsing
with [.sup.3H]thymidine for 16 h.
[0049] FIG. 33 BTLA recognizes a ligand on naive T cells.
Splenocytes from BALB/c and C57BL/6 mice were collected and either
were directly stained (None) or were activated with plate-bound
500A2 (Anti-CD3; 1:200 dilution of ascites fluid) or soluble
anti-IgM (10 .mu.g/ml) for 48 h, and then were stained with BTLA-Fc
or PD-L1-Fc fusion protein (shaded histograms) followed by
anti-human IgG-phycoerythrin (Anti-human IgG-PE), anti-CD4-tricolor
and anti-B220-FITC. Open histograms, staining with human IgG1
isotype control in place of Fc fusion protein.
[0050] FIG. 34 BTLA tetramer staining identifies a ligand on CD4+
and CD8+ cells. (A) Splenocytes and lymph node cells from pooled
C57BL/6 and BALB/c mice were stained with anti-CD8-FITC,
anti-CD4-CyChrome, and either streptavidin-phycoerythrin (open
histograms) or BTLA tetramer-phycoerythrin (shaded histograms). Dot
plots (left) show the CD4-CD8 gates used for single-color
histograms of BTLA tetramer-phycoerythrin staining (right). (B)
Splenocytes from pooled C57BL/6 and BALB/c mice were left untreated
or were activated 48 h with anti-CD3 or anti-IgM as described in
FIG. 33 or with lipopolysaccharide (1 .mu.g/ml) for 24 h and were
stained with anti-B220-FITC, anti-CD4-CyChrome, and either
streptavidin-phycoerythrin (open histograms) or BTLA
tetramer-phycoerythrin (shaded histograms). (C) Thymocytes from
pooled C57BL/6 and BALB/c mice were stained with anti-CD8-FITC,
anti-CD4-CyChrome, and either streptavidin-phycoerythrin (open
histograms) or BTLA tetramer-phycoerythrin (shaded histograms). The
dot plot (left) shows the CD4/CD8 gates used for the single-color
histograms of BTLA-tetramer staining.
[0051] FIG. 35 BTLA ligand expression is modulated during T cell
activation. DO11.10 splenocytes were stimulated with 0.3 .mu.M OVA
peptide in T helper type 1 conditions (T.sub.H1; 10 Uml of IL-12
and 10 .mu.g/ml of anti-IL-4) or T helper type 2 conditions
(T.sub.H2; 100 U/ml of IL-4 and 3 .mu./ml of anti-IL-12). Cultures
were collected after activation (time, horizontal axis) and were
stained with anti-CD4-FITC and BTLA tetramer-phycoerythrin. Filled
circles, streptavidin-phycoerythrin (SA-PE) staining of T helper
type 1 cultures without BTLA tetramer. MFI, mean fluorescence
intensity.
[0052] FIG. 36 HVEM is a ligand for BTLA. (A) NIH 3T3 cells and
BJAB cells were transduced with splenocyte cDNA libraries and were
directly stained with anti-Thy1.1-FITC and the C57BL/6 BTLA
tetramer-phycoerythrin (Before sorting). These cells were sorted
for the highest 0.5% population of BTLA tetramer staining with
BTLA-phycoerythrin tetramer and Thy1.1-FITC and were subjected to
an additional three rounds of similar sequential purification.
After the fourth round of sorting, cell populations were expanded
and cells were stained (After sorting). Numbers in each quadrant
indicate the percentage of live cells in the indicated gate. (B)
BJAB cells were transduced with the retroviruses mHVEM-IRES-GFP
(mHVEM; mouse), hHVEM-IRES-GFP (hHVEM; human), 4-1 BB-IRES-GFP (4-1
BB; mouse) and LT.beta.R-1RES-GFP (LT.beta.R; mouse) and were
stained with C57BL/6 BTLA tetramer-phycoerythrin or BALB/c BTLA
tetramer-phycoerythrin. Numbers in dot plots indicate the
percentage of BTLA tetramer staining in the GFP-positive
population. (C, D) HVEM activates BTLA phosphorylation and SHP-2
association. EL-4 cells (EL4), BJAB cells expressing GFP (BJAB-GFP)
or BJAB cells expressing mouse HVEM (BJAB-mHVEM) were added (+) or
not added (-) for 4 min at 37.degree. C. at a density of
25.times.10.sup.6 cells/ml. Cells were left untreated (-) or were
treated (+) with pervanadate (VO.sub.4) for 4 min. Total cell
lysates were prepared and were immunoprecipitated with 6A6
(anti-mouse BTLA), and immunoblots were probed for SHP-2 (C) or for
phosphotyrosine (D) in immunoprecipitates (IP) or in lysates
without immunoprecipitation. Immunoblots using the isotype control
for immunoprecipitation were negative for SHP-2 association (data
not shown). Data in C and d are representative of four independent
experiments. (E) BJAB cells were transduced with retrovirus
mHVEM-ires-GFP or hHVEM-ires-GFP and were stained with human IgG1
isotype control (hIgG1), mB7x-Fc, mBTLA-Fc or hBTLA-Fc followed by
anti-human IgG-phycoerythrin. Numbers in dot plots show the
percentage of fusion protein staining in the GFP-positive
population.
[0053] FIG. 37 HVEM is the unique ligand for BTLA and interacts
through CRD1. (A) Splenocytes from wild-type (Tnfrsf14+/+) or
HVEM-deficient (Tnfrsf14-/-) mice were stained with
anti-CD4-FITC(CD4+), anti-CD8-FITC(CD8+) or anti-B220-FITC (B220+)
and either C57BL/6 BTLA tetramer-phycoerythrin (shaded histograms)
or streptavidin-phycoerythrin alone (open histograms). (B)
Splenocytes from wild-type (Btla+/+) and Btla-/- mice were stained
with anti-B220-FITC (top) or anti-CD11c-FITC (bottom) and with
either mHVEM-Fc (shaded histograms) or isotype control human IgG1
(open histograms) followed by anti-human IgG-phycoerythrin. (C)
Splenocytes from wild-type (Tnfsf14+/+) and Tnfsf14-/- mice were
stained with B220-FITC (top) or CD11c-FITC (bottom) and mHVEM-Fc or
isotype control human IgG1 (open histograms), followed by
anti-human IgG phycoerythrin. (D) BJAB cells were left uninfected
or were transduced with retroviruses expressing mouse HVEM-GFP
fusion protein (mHVEM-GFP), the HVEM deletion mutant lacking
N-terminal CRD1 as a GFP fusion protein (mHVEMCRDI-GFP), intact
human HVEM (hHVEM-IRES-GFP) or chimeric HVEM containing mouse CRD1
linked to human CRD2 (m/hHVEM-IRES-GFP). Left, cells stained with
BTLA tetramer-phycoerythrin (shaded histograms) or
streptavidin-phycoerythrin alone (open histograms); right, cells
stained with either anti-hHVEM (shaded histograms) or a mouse IgG1
isotype control (9E10) followed by goat anti-mouse
IgG1-phycoerythrin. Single-color histograms were gated on
GFP-positive live cells. Right margin, composition of the HVEM
constructs, with mouse CRDs (open ovals) and human CRDs (shaded
ovals).
[0054] FIG. 38 HVEM expression on APCs inhibits T cell
proliferation. (A) CD4+ cells were purified from BALB/c mice by
magnetic separation and were stimulated (1.times.10.sup.6 cells/ml)
with plate-bound anti-CD3 (2C11; dose, horizontal axis) and
increasing concentrations (wedges; 0, 0.3, 1.0, 3.0 and 10.0
.mu.g/ml) of plate-bound LIGHT. Cultures were pulsed with
[.sup.3H]thymidine at 48 h and were collected at 60 h. Data
represent c.p.m. s.d. from one of three similar experiments. (B)
CD4+ T cells from DO11.10 mice were purified by magnetic
separation, followed by cell sorting for CD4+B220-CD11c-cells to
more than 98% purity, and were added to cultures alone (T alone) or
with (T+) CHO cells expressing I-Ad, I-Ad and B7.1, or I-Ad and
BTLA, plus various concentration of OVA peptide (horizontal axis),
and proliferation was measured as described in A. (C) T cells
prepared as described in b were cultured alone or with CHO cells
expressing I-Ad, or I-Ad and HVEM, plus various concentrations of
OVA peptide, and proliferation was measured as described in A. (D)
T cells prepared as described in b were cultured alone or with CHO
cells expressing I-Ad, or I-Ad and B7.1, or I-Ad, B7.1 and HVEM,
and were activated with various concentration of OVA peptide.
Proliferation was measured as described in A.
[0055] FIG. 39 HVEM inhibits T cell proliferation in a
BTLA-dependent way. (A) Highly purified DO11.10 CD4+ T cells from
wild-type (Btla+/+) or Btla-/- mice were prepared as described in
FIG. 38, were labeled with CFSE and were cultured for 3 or 4 d with
CHO cells expressing I-Ad, or I-Ad and BTLA, or I-Ad and HVEM, plus
0.03 or 0.3 .mu.M OVA peptide. Cells were analyzed by flow
cytometry. Data are single-color histograms of CFSE gated on CD4+ T
cells. Numbers indicate percentage of live cells that have divided
at least once, as indicated by the gate drawn. (B) T cells prepared
as described in a were cultured for 3 or 4 d with CHO cells
expressing I-Ad and B7.1, I-Ad, B7.1 and BTLA, or I-Ad, B7.1 and
HVEM, plus 0.03 or 0.3 .mu.M OVA peptide, and were analyzed as
described in A. Numbers indicate percentage of live cells that have
divided at least once.
[0056] FIG. 40 Polymorphisms in the BTLA Ig domain. (A), Exon 2 of
BTLA, comprising the Ig domain, was amplified by PCR from genomic
DNA of the indicated mouse strains and sequenced. The amino acid
alignment of the Ig domains of BALB/c (SEQ ID NO: 65), MLR/Ipr (SEQ
ID NO: 66), and C57BL/6 (SEQ ID NO: 67) BTLA is shown, starting
with the aspartic acid (D) residue that corresponds to residue 37
of the entire BTLA protein. The last line of the alignment shows a
consensus sequence (bottom), with differences between BALB/c and
MLR/Ipr (#) and differences between BALB/c and C57BL/6 (*) shown.
(B), Strains sharing identical alleles of BTLA are grouped together
under the index headings of BALB/c, MLR/Ipr, and C57BL/6.
[0057] FIG. 41 Production of mAbs to allelic variants of murine
BTLA. A and B, BJAB cells were stably transfected with retroviral
constructs expressing the extracellular/transmembrane domains of
BTLA from C57BL/6 (BJAB.B6 BTLA-GFP, solid histogram) or BALB/c
(BJAB.BALB/c BTLA-GFP, dotted histogram) as GFP fusion proteins.
Cells were stained with the indicated purified mAbs or postimmune
serum (hamster anti-BTLA (A) serum, mouse anti-BTLA (B) serum).
Secondary staining was with either anti-hamster IgG (A) or
anti-mouse Ig (B). Histograms shown are gated on GFP+ BJAB. B6
BTLA-GFP or BJAB.BALB/c BTLA-GFP cells stained separately. Shaded
histogram for the hamster and mouse immune serum are controls using
normal hamster serum or normal mouse serum to stain a mixture of
BJAB. B6 BTLA-GFP and BJAB.BALB/c BTLA-GFP cells. Shaded histogram
for mAb staining shows the isotype control of either hamster IgG
(A) or murine IgG1 (B) staining a mixture of cells. C, Splenocytes
from C57BL/6 or BALB/c wild-type mice (solid histogram) or BTLA-/-
mice (dotted histogram) were stained with 6A6 (left) or 6F7
(right). BTLA-/- staining was equivalent to that of the isotype
control (shaded histogram). D, Lysates from 25.times.10.sup.6 cells
BJAB. B6 BTLA-GFP or BJAB.BALB/c BTLA-GFP cells were
immunoprecipitated (IP) with 10 .mu.g of the indicated Ab and
Western blots probed (Blot) with either 6F7, or with anti-GFP Ab,
as indicated. As controls, cell lysates were immunoprecipitated
with mouse or hamster IgG as indicated (lanes 7-10). E, EL4 cells
were incubated in the absence (-) or presence (+) of pervanadate
for 4 min at 37.degree. C., and lysed in 1% Triton X-100 lysis
buffer, immunoprecipitated (IP) with 6A6 or isotype control Ab (PIP
anti-GST) and Western blots probed (Blot) with anti-SHP-2 as
described.
[0058] FIG. 42 Mapping epitopes recognized by BTLA Abs using Yeast
Display (A and B). A panel of yeast cells expressing the indicated
BTLA Ig domain Aga2 fusion proteins was analyzed for Ab staining.
As a positive control, expression of the fusion protein was
confirmed first for each line using staining with anti-HA Ab
specific for the HA-tag incorporated into the BTLA-Aga2 fusion
protein, and was positive for each line tested (data not shown).
Yeast cells were stained with the anti-BTLA Ab indicated on top of
each column. The amino acid substitutions (and corresponding
nucleotide substitutions) in each yeast line are indicated on the
left. Single-color histograms are marked (*) to indicate mutations
that are not recognized by the corresponding Ab.
[0059] FIG. 43 BTLA shows broad and allelic-specific expression on
lymphoid cell populations. A, Four-color FACS analysis was
conducted on splenocytes from C57BL/6 (solid histogram) or BALB/c
(dotted histogram). Two-color histograms (upper row) of the
indicated markers used to gate cells for single-color histograms of
6A6 (middle row) or 6F7 (lower row) staining are shown. In the
columns one, two, and three, cells were stained with anti-B220
allophycocyanin, anti-CD4 CyChrome, anti-CD8 FITC, and either
biotinylated b-6A6 or b-6F7 followed by SA-PE secondary. In columns
four, five, and six, cells were stained with anti-I-Ad PE (BALB/c
cells) or anti-I-Ab PE (C57BU6 cells), and anti-CD11b FITC (fourth
column), CD11c-FITC (fifth column), or anti-DX-5 FITC (sixth
column), and b-6A6 or b-6F7 followed by SA-CyChrome secondary.
Shaded histograms are staining of a mixture of C57BL/6 and BALB/c
splenocytes using isotype controls of biotinylated hamster IgG
(middle row) and mouse IgG1 (lower row). The numbers shown in top
panels are the percentage of live cells within the indicated gate.
The identity of the gated population is indicated in the panel. B,
C57BL/6 and BALB/c splenocytes were stained with Abs to identify
the following B cell populations: follicular B cells (FO),
IgMlowCD21/CD35int; marginal zone (MZ), IgMhighCD21/CD35high;
transitional (TR), IgMlowCD21/CD35low. Staining with the
pan-BTLA-specific Ab 6F7 revealed equivalent BTLA levels between
strains for all subsets.
[0060] FIG. 44 BTLA is expressed during late stages of B and T
lymphocyte development. A, Thymocytes from C57BL/6 (solid
histogram) or BALB/c (dotted histogram) mice were stained with a
combination of markers, anti-B220 RTC, anti-CD11c FITC, anti-CD11b
FITC, anti-GR-1 FITC, anti-DX-5 FITC, CD4-CyChrome, CD8-PE, and
either biotinylated (b)-6A7 or b-mouse IgG1, and SA
allophycocyanin. The two-color histogram (first panel) is gated on
marker (FITC)-negative live cells, and the numbers indicate the
percentage of cells in the indicated gates. Single-color histograms
for each gate are shown for b-6F7/SA-allophycocyanin staining for
CD4--CD8-- double negative (DN), CD4+CD8+ double positive (DP),
CD4+ single positive (CD4 SP), or CD8+ single positive (CD8 SP)
populations. Shaded histograms are staining the b-mouse IgG1
isotype control. B, Bone marrow cells were stained with anti-B220
allophycocyanin, anti-IgM PerCp Cy5.5, either b-6F7 or murine
IgG1-biotin, and SA-PE. The numbers are the percentage of live
gated cells within the three numbered gates. BTLA expression is
shown in the single-color histograms for each gate; gate 1, Pre-B
cells and Pro-B cells (IgM--B2201ow); gate 2, Immature B cells
(IgM+B2201ow); gate 3, Mature B cells (IgM+B220high). Shaded
regions are mouse IgG1 isotype control staining.
[0061] FIG. 45 BTLA expression during CD4+ T cell activation and
Th1 polarization. A, DO11.10 transgenic T cells were purified by
cell sorting and activated with 0.3 .mu.M OVA peptide 324-336 under
Th1 or Th2 conditions (see Materials and Methods Examples). Cells
were harvested either before activation (Day 0) or on the indicated
day following primary activation, and stained with KJ1-26 Tricolor,
b-6F7, and SA-PE. T cells were restimulated with OVA peptide on day
7 and day 14. B, BALB/c splenocytes were stimulated with 10
.mu.g/ml anti-IgM and 5 .mu.g/ml anti-CD40 (left) or 1 .mu.g/ml LPS
(right). Single-color histograms of B220+ cells (anti-B220-FITC)
are shown for b-6F7/SA-PE staining on day 0 (dotted histogram) and
day 2 (solid histogram) after activation. Shaded histograms are the
biotinylated mouse IgG1 isotype control.
[0062] FIG. 46 BTLA is induced on anergic CD4+ T cells, but not
CD4+CD25+ regulatory T cells. A, HA-TCR T cells were transferred
into and subsequently harvested from B10.D2 mice (naive), C3-HAhigh
mice (anergized) or B10.D2 mice infected with vaccinia-HA
(activated) on days 2, 3, 4, or 7 after transfer as indicated.
After harvest, T cells were isolated using combined magnetic bead
and fluorescence sorting, and cDNA probe prepared and hybridized to
Affymetrix microarrays M174A, M174B, and M174C. Relative BTLA
expression intensity was determined using a latin-squares approach
in Affymetrix Microarray Suite, version 5.1. software. Expression
of myosin Vila gene is shown as a control. B, CFSE-labeled HA-TCR T
cells were adoptively transferred into B10.D2 mice (naive),
C3-HAhigh mice (anergized), or B10.D2 mice immunized with
vaccinia-HA (activated), and harvested on day 6 as in A. Cells were
stained with anti-CD4 allophycocyanin, anti-Thy1.1 PerCP, and
either b-6F7 or murine IgG1-biotin, and SA-PE. BTLA expression is
shown as single-color histogram for CFSE+ (naive) or
CFSE-(activated and anergized) for CD4+ Thy1.1+ donor cells. C,
Splenocytes harvested from recipients as in A were restimulated
with HA peptide and proliferation measured on day 2. D, Splenocytes
and lymph node cells from BALB/c mice were enriched for
CD25-negative and CD25-positive populations using anti-CD25-PE and
magnetic beads as described in Materials and Methods, and stained
with anti-CD4-Cy-chrome, and biotin-conjugated 6F7, or biotin-IgG1,
followed by SA-allophycocyanin. Two-color dot plots are shown for
CD25 and CD4 (left panels), or single-color histograms gated on
CD4+ cells for 6F7 (middle panels) or anti-PD-1 (right panels) for
the CD25- (top row) and CD25+(bottom row) fractions. For BTLA
staining, histograms are shown for both the freshly isolated cells
(thin histogram) and 36 h anti-CD3-activated cells (thick
histogram). Shaded histograms are the staining of the mouse IgG1
istoype control. E, Cells isolated in D were stimulated with the
indicated amount of anti-CD3 and proliferation measured after 2
days.
[0063] FIG. 47 BTLA-/- mice have modestly augmented IgG3 responses
to T-independent Ag. 129SvEv wild-type mice or BTLA-/- mice (n=5)
were immunized with 50 .mu.g NP-Ficoll in alum by i.p. injection.
At day 14, relative isotype-specific anti-NP Ab titer in serum was
determined by ELISA. Data are shown as the percentage of the Ab
titer produced in serum of naive BTLA+/+ or BTLA-/- mice.
Mean.+-.SD is shown.
[0064] FIG. 48 BTLA-/- parental cells engraft and initially
expand
[0065] FIG. 49 BTLA-/- parental cells fail to survive following
transfer
[0066] FIG. 50 BTLA-/- cells do not persist as GHVD progresses
until about day 9, the expansion of WT and BTLA KO donor T cells is
similar; At later times, BTLA-/- show rapid decrease is the number
of remaining donor cells.
[0067] FIG. 51 HVEM induces BTLA-phosphorylation and SHP-2
recruitment in trans.
[0068] FIG. 52 HVEM on APCs inhibits T cell proliferation through
BTLA. HVEM on APCs inhibits T cell proliferation. HVEM does not
inhibit BTLA-/- T cells.
[0069] FIG. 53 HVEM on APCs inhibits T cell proliferation through
BTLA.
[0070] FIG. 54 HVEM inhibition is overcome by strong costimulation.
HVEM inhibition of T cells is less with stronger co-stimulation.
HVEM inhibition of T cells is less at highest antigen doses.
[0071] FIG. 55 6A6 binds to amino acid residues E34 and R73 of
BTLA. Antibody interactions are most affected by E34Q and R73Q
mutations, and slightly affected by H23Q and W56C mutations. E34
and R73 are E63 and R102 in full length protein.
[0072] FIG. 56 shows the amino acid sequence of human BTLA, also
found at Genbank Accession No. AAP44003.1 (SEQ ID NO: 64).
[0073] FIG. 57 PD-1 and BTLA are expressed on BAL CD4 T cells:
C57BL/6 mice were sensitized and challenged with Ovalbumin. On days
1, 3, 4, and 7 following challenge, groups of mice were euthanized
and the cells recovered in the BAL analyzed for expression of CD4
and PD-1 or BTLA by 2-color flow cytometry. The percentage of cells
positive for CD4 as a fraction of either the total sample or of the
lymphocyte gate as well as the total number of CD4+ cells recovered
is indicated in each box. Histograms of PD-1 or BTLA expression on
the CD4+ cells are shown for days 3, 4 and 7. Representative data
of 3 independent experiments is presented.
[0074] FIG. 58 PD-1 and BTLA have a minor effect on acute allergic
airway inflammation: C57BU6, PD-1-/- and BTLA-/- mice (n=5 per
group) were sensitized ad challenged with OVA. 3 days following
challenge, the mice were euthanized and samples collected for
analysis. (A) Total cell counts in the BAL fluid. (B) Differential
analysis of the cell types present in the BAL. (C) Representative
fields of H and E stained sections (40.times. magnification).
*=P<0.05 **=P<0.005 compared to C57BU6 by 2 tailed T test.
Representative data from 5 independent experiments is shown.
[0075] FIG. 59 Expression of the ligands for PD-1 and BTLA during
allergic airway inflammation: Total RNA was isolated from whole
lungs of allergen challenged mice on the indicated days
post-challenge or from primary cultured murine tracheal epithelial
cells (mTEC). RT-PCR was performed using specific primers that
spanned intronic sequences of each gene. Shown is representative
data from 2 independent experiments.
[0076] FIG. 60 shows that PD-1 and BTLA-deficient mice have a
prolonged duration of airway inflammation: C57BL/6, PD-1-/- and
BTLA-/- mice were sensitized and challenged with OVA. On days 10
and 15 cohorts of mice (n=5/group) were euthanized and samples
collected for A) analysis of the BAL and B) histology. *=p<0.05
compared to C57BL/6 using a 2 tailed T-test.
[0077] FIG. 61 shows graphs and micrographs illustrating that BTLA
and HVEM, but not PD-1, regulate the survival of partially
MHC-mismatched cardiac allografts. A, The lack of BTLA or HVEM, or
administration of a neutralizing anti-BTLA mAb, led to rejection of
all MHC class II-mismatched cardiac allografts within 3-4 wk of
transplantation, whereas wild-type (WT) recipients accepted Bm12
allografts indefinitely. Data were generated from six to 12
allografts/group; p<0.001 for BTLA-/-, HVEM-/-, or anti-BTLA
mAb-treated group vs respective WT controls. Panels at the right
show acute cellular rejection of Bm12 allografts harvested 2 wk
after transplant from BTLA-/-, but not WT, recipients
(H&E-stained paraffin sections; original magnifications,
.times.300). B, In contrast to BTLA and HVEM, a lack of PD-1 still
allowed >80% long-term survival of MHC class II-mismatched
cardiac allografts (p<0.05 compared with isotype-treated WT
control), and an absence of both PD-1 and BTLA (DKO) led to only a
minor acceleration of allograft rejection compared with lack of
BTLA alone (p<0.05 vs BTLA-/- alone) in B6 recipients of Bm12
cardiac allografts. Data were generated from four to eight
allografts per group. C, Lack of BTLA led to rejection of all MHC
class I-mismatched cardiac allografts, whereas WT recipients
accepted Bm1 allografts indefinitely. Data were generated from 6 to
12 allografts/group (p<0.001). Panels at the right show
histologic evidence of developing cellular rejection of Bml
allografts harvested 4 wk after transplant from BTLA-/-, but not
WT, recipients (H&E-stained paraffin sections; original
magnifications, .times.300).
[0078] FIG. 62 shows graphs illustrating that BTLA suppresses T
cell responses to MHC class II alloantigens. A, Intragraft mRNA
expression of BTLA, PD-1, and ligands was determined by qPCR; data
are expressed as the fold increase compared with naive heart and
are representative of three separate experiments (Bm123B6 cardiac
allografts). B, Compared with wild-type (WT) CD4+ T cells, CD4+ T
cells from BTLA-/- mice had markedly enhanced proliferative
responses to Bm12 APC. Data at 72 h are expressed as a percentage
of live BrdU+ CD4 cells at each stimulator (S) to responder (R)
ratio (pooled triplicate wells). C, Assessment of
alloactivation-induced CD4+ T cell proliferation at 72 h induced by
irradiated Bm12 APC; the percentage of dividing CD4+ T cells was
determined by CFSE dilution. D, Markedly increased proliferation of
CFSE-labeled BTLA-/- CD4+ T cells 72 h after transfer into
irradiated Bm12 hosts. Data are representative of two experiments
with similar results. E, Marginally increased proliferation of
CFSE-labeled BTLA-/- CD8+ T cells 72 h after transfer into
irradiated Bm12 hosts. Data are representative of two experiments
with similar results. F, Significantly increased responder
frequency in BTLA-/- recipients of class II-mismatched cardiac
allografts, as shown by harvesting of recipient spleens 10 days
after transplant and stimulation of recipient splenocytes in vitro
with irradiated Bm12 (p<0.001 at all ratios) or B6 DC (syngeneic
control) for 24 h. Donor-specific responder frequency was expressed
as the number of IFN-.gamma. spot-forming cells (SFC) per
1.times.10.sup.6 splenocytes, and data (mean.+-.SD) are
representative of two experiments.
[0079] FIG. 63 shows graphs and photographic images demonstrating
that BTLA targeting prolongs survival of fully MHC-mismatched
cardiac allografts. Targeting of BTLA significantly prolonged
BALB/c cardiac allograft in fully allogeneic B6 recipients, as
shown using BTLA-/- recipients (A) and anti-BTLA mAb in wild-type
(WT) mice (B). C, In addition, a subtherapeutic course of rapamycin
(RPM; 10 .mu.g/kg/day, i.p., for 14 days) significantly prolonged
cardiac allograft survival compared with either identically treated
WT mice or BTLA-/- controls. Allograft survival data in A-C were
obtained from six to eight transplants per group. D, BALB/c hearts
transplanted to WT or BTLA-/- B6 mice were harvested 7 days after
transplant for qPCR. Data from three allografts per group are
expressed as the fold increase compared with native heart. E,
Western blots of CXCR3 and IP-10 proteins, using extracts of three
allografts per group. The effects of targeting BTLA, alone or in
combination with low dose RPM, on allogeneic T cell proliferation
and cytokine production were determined by adoptive transfer of
CFSE-labeled splenocytes from WT or BTLA-/- mice to B6D2F1 hosts,
and recipient spleens were harvested at 72 h. The responses of
donor T cells were identified by gating on Kd-Dd-cells. Data are
shown as an overlay of CFSE histograms (F) and analysis of
intracellular cytokine production (G). The figure in each box is
the percentage of the indicated population, and data are
representative of two experiments with similar results.
[0080] FIG. 64 shows graphs illustrating the dominant role of PD-1
in regulating the survival of fully MHC-mismatched cardiac
allografts. A, Dual PD-1/BTLA-/- (DKO) recipients rejected fully
MHC-disparate allografts at the same speed as wildtype (WT)
recipients. B, Neutralization of PD-1 in BTLA-/- recipients
reversed the prolongation of survival seen in BTLA-/- mice
(p<0.001). c, The dominant role of PD-1 was also seen by the
quick rejection of allografts in DKO mice, despite therapy with
rapamycin (RPM; 10 .mu.g/kg/day, i.p., for 14 days), in marked
contrast to the prolonged survival in BTLA-/- recipients treated
with the same dose of RPM (p<0.001). D, The key contribution of
PD-1, but not BTLA, in promoting the survival of fully
MHC-mismatched cardiac allografts in RPM-treated recipients was
confirmed by the rapid onset of acute rejection in BTLA-/-
recipients treated with anti-PD-1 mAb (p<0.001).
[0081] FIG. 65 shows plots that demonstrate increased PD-1
expression and function by alloreactive T cells of BTLA-/-
recipients of fully MHC-mismatched cardiac allografts. A,
Intragraft mRNA expression of BTLA, PD-1, and ligands was
determined by qPCR. Data are expressed as the fold increase
compared with naive heart and are representative of three separate
experiments (BALB/c3B6 cardiac allografts). B, PD-1 expression by
alloreactive T cells determined by adoptive transfer of
CFSE-labeled wild-type (WT) or BTLA-/- splenocytes to irradiated
Bm12 or B6D2F1 hosts, with or without added rapamycin (RPM; 0.01
mg/kg, i.p., for 3 days). Figures indicate the percentages of PD-1
cells in the divided and undivided donor T cell populations. C,
Increased proliferation of CFSE-labeled T cells from DKO mice or
PD-1-/- mice vs WT or BTLA-/- controls after adoptive transfer to
F1 hosts, with or without RPM therapy. Analysis of corresponding
intracellular cytokine production by the groups shown in C was
undertaken, alone (D) or in conjunction with RPM therapy (E). Cells
were stained with Kd-PE and CD4- or CD8-PerCP, and IL-2 or
IFN-.gamma. APCs and donor cells were identified as the
Kd-Dd-population; the percentage of each indicated population is
shown.
[0082] FIG. 66 shows graphs illustrating that as the strength of T
cell signaling increases, PD-1 induction predominates over that of
BTLA. Increasing T cell activation by mature fully allogeneic
BALB/c bone marrow-derived DC leads to increasing expression of
PD-1, rather than BTLA, by C57BL/6 CD4 and CD8 T cells, as shown by
flow cytometric analysis of cells cultured at varying stimulator
(S) to responder (R) ratios for 72 h. Data are representative of
three such experiments.
DETAILED DESCRIPTION OF THE INVENTION
[0083] A negative costimulatory receptor analogous to CTLA-4 was
herein identified on B cells and T cells. B and T lymphocyte
attenuator (BTLA) is an immunoglobulin domain-containing
glycoprotein with a Grb2 binding site, an immunoreceptor
tyrosine-based inhibitory motif (ITIM), and an immunoreceptor
tyrosine-based switch motif (ITSM). Partial BTLA sequences were
disclosed previously (WO 99/40100 and WO 02/07294) though the
complete sequence, distribution, and function of BTLA was not
reported. Additionally, the partial BTLA sequences disclosed were
asserted to correspond to secreted proteins rather than a
functional receptor on the surface of lymphocytes.
[0084] BTLA acts as a negative regulator of both B and T lymphocyte
activity. Crosslinking BTLA with antigen receptors induces its
tyrosine phosphorylation and association with the Src homology
domain 2 (SH2)-containing protein tyrosine phosphatases SHP-1 and
SHP-2, and attenuates production of interleukin 2 (IL-2).
BTLA-deficient T cells show increased proliferation, and
BTLA-deficient mice have increased specific antibody responses and
enhanced sensitivity to experimental autoimmune
encephalomyelitis.
[0085] Based on indirect evidence, the ligand for BTLA was
previously asserted to be B7x. However, as disclosed herein, B7x
does not bind to BTLA. The identification of BTLA's cognate ligand
thus remains highly desirable for an understanding of BTLA
function, and for diagnostic and therapeutic purposes.
[0086] Hence, the present disclosure is directed to the
identification and characterization of BTLA, a novel
down-regulatory lymphocytic receptor. As shown herein, BTLA is
expressed in both B and T cells and exhibits dynamic expression,
with very low expression levels in naive B and T cells, rapid
induction upon stimulation of cells with antigen, and increased
expression in activated B and T cells. Moreover, there is a high
level of BTLA expression in Th1 cells and a much lower level in Th2
cells following Th polarization. The present invention further
demonstrates that stimulation of BTLA (e.g., via the interaction of
HVEM and BTLA) inhibits T cell activity, and that loss of BTLA
function leads to T cell hyperactivation. Thus, as disclosed
herein, BTLA represents a novel negative regulatory receptor for
both B and T lymphocytes, and plays a role in controlling
inflammatory responses and autoimmunity.
[0087] The present disclosure is also directed to the
characterization of B7x, a new member of the B7 family the
expression of which is not limited to lymphoid tissue. As shown
herein, B7x is expressed in cells of non-hematopoietic origin, as
well as in cells of the hematopoietic lineage, and is highly
expressed in a variety of tumor cells. The present invention
further demonstrates for the first time that B7x is capable of
inhibiting immune-responses, and in particular, both B and T cell
responses, via an interaction with BTLA. The present invention
further identifies the role of B7x in the maintenance of
immunological self-tolerance and the inhibition of autoimmunity.
The present invention also identifies the role of B7x in promoting
the survival of tumor cells by inhibiting T cell activation.
[0088] The present disclosure also establishes that Herpes virus
entry mediator (HVEM) is the cognate ligand of BTLA. HVEM belongs
to the TNF receptor family of proteins and is itself a
costimulatory receptor expressed on naive T cells. HVEM is also
expressed to a lesser extent on dendritic cells, resting B cells,
and macrophages. HVEM has four extracellular cysteine-rich domains
(CRDs) and interacts with two known TNF family members, LIGHT and
lymphotoxin alpha (LT.alpha.), through CRD2 and CRD3. For further
discussion of HVEM, see for example Granger et al., Cytokine Growth
Factor Rev., 14:289-96, 2003; and Croft, Nat. Rev. Immunol.,
3:609-620, 2003. As disclosed herein, HVEM directly binds to BTLA
and stimulates BTLA activity. As further disclosed herein, HVEM
binding to BTLA can reduce the activation of BTLA expressing
lymphocytes, as well as decrease the effector activity of BTLA
expressing lymphocytes.
[0089] The present disclosure also establishes that B7x does not
directly bind to BTLA and does not directly modulate BTLA activity.
B7x is expressed in a wide variety of normal and cancer cells, and
was previously reported to be a ligand for BTLA based on indirect
evidence. It was postulated that the interaction of B7x with BTLA
inhibited both B and T cell responses, and was a means by which
B7x-expressing tumor tissue inhibited the activity of
tumor-specific T cells. It was further posited that B7x expressed
on non-tumor non-lymphoid tissue served to maintain immunological
tolerance to self antigens.
[0090] Stemming from the discovery of the HVEM-BTLA interaction, in
one aspect, the present invention provides BTLA antibodies,
sometimes referred to herein as BTLA blocking antibodies. A BTLA
antibody of the invention is capable of specifically binding to a
BTLA protein and is capable of reducing the binding of the BTLA
protein to an HVEM protein. Especially preferred are BTLA
antibodies that specifically bind to a region of the BTLA Ig
domain, which region binds to the HVEM CRD1 domain. Such a BTLA
antibody is capable of binding to a fragment of the BTLA Ig domain,
which fragment is capable of binding to an HVEM CRD1 domain.
[0091] Aberrant BTLA activity, for example, as a result of aberrant
BTLA/HVEM interaction, aberrant BTLA/B7x interaction, or aberrant
BTLA, HVEM or B7x expression, can-promote diseases associated with
T cell activity. As noted above, a high level of B7x expression on
tumor cells facilitates the inhibition of T cell activation by
tumor cells, and tumor cell survival. Conversely, a low level of
B7x expression on non-lymphoid tissue can render the tissue
susceptible to attack by autoreactive T and B cells, and
predisposes a subject to autoimmune disease. Similarly, an
increased level of BTLA expression in lymphocytes, or increased
effective activity, can sensitize lymphocytes to inhibitory
costimulation, making them less responsive to antigen, suppressing
the immune system, and potentiating the growth of tumor tissue.
Conversely, a decreased level of BTLA expression in lymphocytes, or
decreased effective activity, can make lymphocytes refractive to
particular inhibitory costimulation signals, such as those of B7x,
and lead to a hyperimmune state characterized by a predisposition
to autoimmune disease.
[0092] In accordance with the foregoing, the present invention
provides methods and compositions for modulating immune
responses.
[0093] In one embodiment, bioactive agents and methods for
increasing and/or up-regulating B and T cell activity are provided.
In a preferred embodiment, such bioactive agents comprise
antagonists of BTLA-mediated signaling. In a particularly preferred
embodiment, such bioactive agents comprise blocking agents as
described herein, and in a specific embodiment, such blocking
agents are capable of interfering with the interaction of BTLA and
B7x or BTLA and HVEM. In a further embodiment, adjuvant
compositions are provided utilizing BTLA, HVEM, and/or B7x blocking
agents and other antagonists of BTLA-mediated signaling.
[0094] In an alternative embodiment, bioactive agents and methods
for inhibiting and/or down-regulating B and T cell activity are
provided. In a preferred embodiment, such bioactive agents comprise
agonists of BTLA-mediated signaling. In a particularly preferred
embodiment, such bioactive agents comprise mimicking agents as
described herein, and in a specific embodiment, such mimicking
agents are capable of replacing and/or augmenting the interaction
of BTLA and B7x or the interaction of BTLA and HVEM. In a further
embodiment, immunsuppressive compositions are provided utilizing
BTLA, HVEM, and/or B7x mimicking agents and other agonists of
BTLA-mediated signaling.
[0095] In a further embodiment, methods and compositions for
modulating immunoglobulin production by B cells is provided.
[0096] The methods and compositions described herein will find
advantageous use in immunotherapy, including, e.g., autoimmunity,
immune suppression, cancer immunotherapy and immune adjuvants.
(I) B7x and BTLA Nucleic Acids and Proteins
[0097] Murine B7x encodes a 283 amino acid protein and shares
varying degrees of identity with mouse B7.1 (13%), B7.2 (13%), B7h
(14%), PD-L1 (20%), PD-L2 (16%) and B7-H3 (24%).
[0098] Two human epithelial cell cDNAs encoding a polypeptide
(previously called hypothetical protein FLJ22418) having similarity
to mouse B7x were identified, and two EST clones (GenBank accession
nos. BF680206 and A1799522) corresponding to the same human
nucleotide sequence have been identified.
[0099] Human B7x encodes a 282 amino acid protein and has 87% amino
acid identity with mouse B7x. Notably, this is much higher than the
40-46% identity between human and mouse B7.1 or B7.2.
[0100] B7x protein is a type I transmembrane protein that belongs
to the immunoglobulin (Ig) superfamily. It has a signal peptide in
its N-terminus, single extracellular IgV- and IgC-like domains, a
transmembrane region and a very short cytoplasmic stub of only 1
amino acid. The absence of a heptad structure and B30.2 domains
distinguishes B7x from the butyrophilins and myelin oligodendrocyte
glycoproteins.
[0101] Numerous potential N-linked glycosylation sites are present
in the extracellular portion of B7x. Like other members of the B7
family, B7x has four conserved cysteine residues that are likely
involved in the formation of IgV- and IgC-like domains.
[0102] In both mouse and human, B7x genes are located on different
chromosomes from the other known B7 family members. Mouse B7x
consists of 6 exons occupying 70.15 kb in the F3 region of
chromosome while human B7x is of similar size and organization in
the p12/13.1 region of chromosome 1. A phylogenetic comparison of
the seven known members of the B7 family from human and mouse was
performed using PAUP. This analysis suggests that the extended B7
family can be divided into 3 groups: group I including B7.1, B7.2
and B7h, group II consisting of PD-L1 and PD-L2, and group III
containing B7x and B7-H3.
[0103] The BTLA protein comprises a signal sequence, an
extracellular V-like Ig domain, a transmembrane region, and an
intracellular domain of approximately 100 amino acids that
comprises several motifs implicated in signal transduction.
Notably, three tyrosine residues within the cytoplasmic domain are
contained within sequence motifs that are conserved between mouse
and human and are implicated in signal transduction. Particularly,
conserved tyrosine residues are found within a Grb2 interaction
site and within two ITIM sequences.
[0104] In one aspect, the present invention provides nucleic acids
encoding B7x proteins, and B7x proteins so encoded, which are
capable of modulating T cell activation.
[0105] In one aspect, the present invention provides nucleic acids
encoding BTLA proteins, and BTLA proteins so encoded, which are
capable of modulating T cell activation.
[0106] The B7x and BTLA proteins of the present invention may be
identified in several ways. "Protein" in this sense includes
proteins, polypeptides, and peptides. Included among BTLA proteins
are protein fragments, extracellular fragments being particularly
preferred, which possess at least one activity of the BTLA protein
set forth by SEQ ID NO:8 or 10, and/or at least one epitope of the
BTLA protein set forth by SEQ ID NO:8 or 10. Included among B7x
proteins are protein fragments, extracellular fragments being
particularly preferred, which possess at least one activity of the
B7x protein set forth by SEQ ID NO:1 or 2 and/or at least one
epitope of the BTLA protein set forth by SEQ ID NO:1 or 2.
[0107] A B7x protein may be identified by amino acid sequence
identity or similarity to the amino acid sequences set forth in SEQ
ID NO:1 or 2.
[0108] A B7x protein may be identified by its ability to bind to
the surface of T cells, preferably activated CD4+ and/or activated
CD8+ T cells. A B7x protein may also be identified by its ability
to bind to B cells expressing BTLA. Generally, a B7x protein may be
identified by its ability to bind to B or T cells expressing
BTLA.
[0109] A B7x protein may be identified by its ability to bind to a
BTLA protein described herein.
[0110] A B7x protein may be identified by its ability to modulate
T-lymphocyte activation, preferably Th1 activation. More
preferably, a B7x protein may be identified by its ability to bind
to BTLA expressed on a T cell and to thereby inhibit T cell
activation.
[0111] A B7x protein may be identified by its elevated expression
in tumor cells.
[0112] A BTLA protein may be identified by amino acid sequence
identity or similarity to the amino acid sequences set forth in SEQ
ID NO:8 or 10.
[0113] A BTLA protein may be identified by its ability to bind to
the surface of tumor cells expressing B7x.
[0114] A BTLA protein may be identified by its ability to bind to a
B7x protein described herein.
[0115] A BTLA protein may be identified by its expression in Tc and
Th cells, and its elevated expression in polarized Th1 cells.
[0116] A BTLA protein may be identified by its ability to modulate
T cell activation, preferably CD4+ and CD8+ T cell activation, when
expressed in the T cell, and upon binding to ligand. Preferably,
the ligand is B7x, a fragment thereof, or a fusion protein
comprising B7x, or a fragment thereof.
[0117] B7x and BTLA proteins may initially be identified by
sequence identity or similarity to the sequences set forth in the
figures, as further described below.
[0118] In a preferred embodiment, B7x and BTLA proteins have
sequence identity or similarity to the sequences and one or more
B7x and BTLA bioactivities, respectively. Such sequence identity or
similarity can be based upon the overall sequence.
[0119] In a preferred embodiment, B7x proteins provided herein
comprise an amino acid sequence having at least about 80%, more
preferably at least about 85%, more preferably at least about 90%,
more preferably at least about 95%, more preferably at least about
98% identity to the amino acid sequence set forth in SEQ ID NO:1 or
2. In a preferred embodiment, the B7x protein comprises the amino
acid sequence set forth in SEQ ID NO:1 or 2.
[0120] In a preferred embodiment, BTLA proteins provided herein
comprise an amino acid sequence having at least about 80%, more
preferably at least about 85%, more preferably at least about 90%,
more preferably at least about 95%, more preferably at least about
98% identity to the amino acid sequences set forth in SEQ ID NO:6,
or 8, or 10. In a preferred embodiment, the BTLA protein comprises
the amino acid sequence set forth in SEQ ID NO:6, or 8, or 10.
[0121] In a preferred embodiment, a B7x protein provided herein
comprises an extracellular domain as shown in FIG. 5. In a
preferred embodiment, the B7x protein comprises an IgV-like domain
and an IgC-like domain.
[0122] In another preferred embodiment, a B7x protein provided
herein comprises an extracellular domain and a transmembrane domain
as shown in FIG. 5. In a preferred embodiment, the B7x protein
comprises an IgV-like domain and an IgC-like domain, and a
transmembrane domain.
[0123] In a preferred embodiment, a B7x protein provided herein
comprises a cytoplasmic domain as shown in FIG. 5.
[0124] In a preferred embodiment, a B7x protein provided herein
comprises a cytoplasmic domain and a transmembrane domain as shown
in FIG. 5.
[0125] In a preferred embodiment, a B7x protein provided herein
comprises an extracellular domain, a transmembrane domain, and a
cytoplasmic domain as shown in FIG. 5.
[0126] In a preferred embodiment, the invention provides B7x
protein extracellular fragments that are capable of interacting
with BTLA but incapable of activating BTLA-mediated signaling. In
another preferred embodiment, the invention provides B7x protein
extracellular fragments that are capable of interacting with BTLA
and capable of activating BTLA-mediated signaling.
[0127] The present invention also provides BTLA proteins.
[0128] In a preferred embodiment, a BTLA protein provided herein
comprises a signal sequence, an extracellular Ig domain, a
transmembrane region, and an intracellular domain of approximately
100 amino acids that comprises three tyrosine residues within a
Grb2 interaction site and two ITIM sequences.
[0129] In another preferred embodiment, a BTLA protein provided
herein comprises an extracellular Ig domain, a transmembrane
region, and an intracellular domain of approximately 100 amino
acids that comprises three tyrosine residues within a Grb2
interaction site and two ITIM sequences.
[0130] In another preferred embodiment, a BTLA protein provided
herein comprises an extracellular Ig domain, as shown in FIG.
21.
[0131] In a preferred embodiment, the invention provides BTLA
protein fragments comprising a V-like Ig domain, wherein the
Ig-like domain comprises an amino acid sequence having at least
about 70% identity to residues 43-134, more preferably 47-133, more
preferably 51-117 of the amino acid sequence set forth in SEQ ID
NO:8.
[0132] In an especially preferred embodiment, the invention
provides BTLA protein fragments comprising a V-like Ig domain,
wherein the Ig-like domain comprises the amino acid sequence of
residues 43-134, more preferably 47-133, more preferably 51-117 of
the amino acid sequence set forth in SEQ ID NO:8.
[0133] In a preferred embodiment, the invention provides BTLA
protein fragments comprising a V-like Ig domain, wherein the
Ig-like domain comprises an amino acid sequence having at least
about 70% identity to residues 57-142, more preferably residues
57-124 of the amino acid sequence set forth at SEQ ID NO:10.
[0134] In an especially preferred embodiment, the invention
provides BTLA protein fragments comprising a V-like Ig domain,
wherein the Ig-like domain comprises the amino acid sequence of
residues 57-142, more preferably residues 57-124 of the amino acid
sequence set forth at SEQ ID NO:10.
[0135] In a preferred embodiment, the invention provides BTLA
protein extracellular fragments having at least about 70% identity
to a portion of the extracellular domain of BTLA protein set forth
by SEQ ID NO:8, particularly to a portion (at least about 20 amino
acids) of the sequence from about residue 31 to about residue 153
in SEQ ID NO:8.
[0136] In an especially preferred embodiment, the invention
provides BTLA protein extracellular fragments comprising at least
about a 20 amino acid sequence from about residue 31 to about
residue 153 in SEQ ID NO:8.
[0137] In a preferred embodiment, the invention provides BTLA
protein extracellular fragments having at least about 70% identity
to a portion of the extracellular domain of BTLA protein set forth
by SEQ ID NO:8, particularly to a portion (at least about 20 amino
acids) of the sequence from about residue 30 to about residue 181
in SEQ ID NO:10.
[0138] In an especially preferred embodiment, the invention
provides BTLA protein extracellular fragments comprising at least
about a 20 amino acid sequence from about residue 30 to about
residue 181 in SEQ ID NO:10.
[0139] In a preferred embodiment, a BTLA protein provided herein
comprises a signal sequence and an extracellular V-like Ig domain,
as shown in FIG. 21.
[0140] In another preferred embodiment, a BTLA protein provided
herein comprises an extracellular V-like Ig domain and a
transmembrane region, as shown in FIG. 21.
[0141] In another preferred embodiment, a BTLA protein provided
herein comprises a signal sequence, an extracellular V-like Ig
domain and a transmembrane region, as shown in FIG. 21.
[0142] In another preferred embodiment, a BTLA protein provided
herein comprises an intracellular domain of approximately 100 amino
acids, which further comprises a Grb2 interaction site and two ITIM
sequences, as shown in FIG. 21.
[0143] In another preferred embodiment, a BTLA protein provided
herein comprises a transmembrane region and an intracellular domain
of approximately 100 amino acids, which further comprises a Grb2
interaction site and two ITIM sequences, as shown in FIG. 21.
[0144] In a highly preferred embodiment, a BTLA protein provided
herein lacks the amino acid sequence encoded by exon 2 shown in
FIG. 20, and accordingly lacks the Ig domain depicted in FIG. 19.
In a preferred embodiment, such a BTLA protein possesses BTLA
protein function.
[0145] Fragments are included in the definition of B7x and BTLA
proteins herein.
[0146] In a preferred embodiment, a B7x protein provided herein
consist essentially of an extracellular domain as shown in FIG. 5.
In a preferred embodiment,
[0147] the B7x protein consists essentially of an IgV-like domain
and an IgC-like domain.
[0148] In another preferred embodiment, a B7x protein provided
herein consists essentially of an extracellular domain and a
transmembrane domain as shown in FIG. 5. In a preferred embodiment,
the B7x protein consists essentially of an IgV-like domain and an
IgC-like domain, and a transmembrane domain.
[0149] In a preferred embodiment, a B7x protein provided herein
consists essentially of a cytoplasmic domain as shown in FIG.
5.
[0150] In a preferred embodiment, a B7x protein provided herein
consists essentially of a cytoplasmic domain and a transmembrane
domain as shown in FIG. 5.
[0151] BTLA protein fragments are also provided.
[0152] In a preferred embodiment, a BTLA protein provided herein
consists essentially of an extracellular V-like Ig domain, as shown
in FIG. 21.
[0153] In a preferred embodiment, a BTLA protein provided herein
consists essentially of a signal sequence and an extracellular
V-like Ig domain, as shown in FIG. 21.
[0154] In another preferred embodiment, a BTLA protein provided
herein consists essentially of an extracellular V-like Ig domain
and a transmembrane region, as shown in FIG. 21.
[0155] In another preferred embodiment, a BTLA protein provided
herein consists essentially of a signal sequence, an extracellular
V-like Ig domain and a transmembrane region, as shown in FIG.
21.
[0156] In another preferred embodiment, a BTLA protein provided
herein consists essentially of an intracellular domain of
approximately 100 amino acids, which further comprises a Grb2
interaction site and two ITIM sequences, as shown in FIG. 21.
[0157] In another preferred embodiment, a BTLA protein provided
herein consists essentially of a transmembrane region and an
intracellular domain of approximately 100 amino acids, which
further comprises a Grb2 interaction site and two ITIM sequences,
as shown in FIG. 21.
[0158] As used herein, peptide refers to at least two covalently
attached amino acids, which includes proteins, polypeptides, and
oligopeptides. The protein may be made up of naturally occurring
amino acids and peptide bonds, or synthetic peptidomimetic
structures. Thus, "amino acid" or "peptide residue" as used herein
means both naturally occurring and synthetic amino acids. For
example, homo-phenylalanine, citrulline, and norleucine are
considered amino acids for the purposes of the invention. "Amino
acids" also includes imino residues such as proline and
hydroxyproline. The side chains may be either the D- or
L-configuration, or combinations thereof. Although the bond between
each amino acid is typically an amide or peptide bond, it is to be
understood that peptide also includes analogs of peptides in which
one or more peptide linkages are replaced with other than an amide
orpeptide linkage, such as a substituted amide linkage, an isostere
of an amide linkage, or a peptide or amide mimetic linkage (See,
for example, Spatola, "Peptide Backbone Modifications," in
Chemistry and Biochemistry of Amino Acids Peptides and Proteins,
Weinstein, Ed., Marcel Dekker, New York (1983); Son et al., J. Med.
Chem. 36:3039-3049 (1993); and Ripka and Rich, Curr. Opin. Chem.
Biol. 2:441-452 (1998)).
[0159] Typically, peptides will generally be less than about 100
amino acids, less that about 50 amino acids, or less than about 20
amino acids.
[0160] A peptide herein is typically an isolated or purified
peptide. As used herein, a peptide is said to be "isolated" or
"purified" when it is substantially free of cellular material or
free of chemical precursors or other chemicals. The peptides of the
present invention can be purified to homogeneity or other degrees
of purity. The level of purification will be based on the intended
use. The phrase "substantially free of chemical precursors or other
chemicals" includes preparations of the peptide in which it is
separated from chemical precursors or other chemicals that are
involved in its synthesis. Preparations of a peptide are
substantially free of precursors in preparation having less than
about 30% (by dry weight) chemical precursors or other chemicals,
less than about 20% chemical precursors or other chemicals, less
than about 10% chemical precursors or other chemicals, or less than
about 5% chemical precursors or other chemicals.
[0161] The peptides of this invention can be made by chemical
synthesis methods which are well known to the ordinarily skilled
artisan. See, for example, Fields et al., Chapter 3 in Synthetic
Peptides: A User's Guide, ed. Grant, W. H. Freeman & Co., New
York, N.Y., 1992, p. 77. Peptides can be synthesized using the
automated Merrifield techniques of solid phase synthesis with the
aNH2 protected by either t-Boc or Fmoc chemistry using side chain
protected amino acids on, for example, an Applied Biosystems
Peptide Synthesizer Model 430A or 431.
[0162] After complete assembly of the desired peptide, the resin is
treated according to standard procedures to cleave the peptide from
the resin and deblock the functional groups on the amino acid side
chains. The free peptide is purified, for example by HPLC, and
characterized biochemically, for example, by amino acid analysis,
mass spectrometry, and/or by sequencing. Purification and
characterization methods for peptides are well known to those of
ordinary skill in the art.
[0163] Longer synthetic peptides can be synthesized by well-known
recombinant DNA techniques. Many standard manuals on molecular
cloning technology provide detailed protocols to produce the
peptides of the invention by expression of recombinant DNA and RNA.
To construct a gene encoding a peptide of this invention, the amino
acid sequence is reverse translated into a nucleic acid sequence,
preferably using optimized codon usage for the organism in which
the gene will be expressed. Next, a gene encoding the peptide is
made, typically by synthesizing overlapping oligonucleotides which
encode the peptide and necessary regulatory elements. The synthetic
gene is assembled and inserted into the desired expression vector.
Nucleic acids which comprise sequences that encode the peptides of
this invention are also provided. The synthetic gene is inserted
into a suitable cloning vector and recombinants are obtained and
characterized. The peptide is then expressed under conditions
appropriate for the selected expression system and host. The
peptide is purified and characterized by standard methods.
[0164] Recombinant techniques that are well known in the art may be
used to combine BTLA or B7x protein fragments disclosed herein with
other moieties for a variety of purposes, as further discussed
below. These processes involve the manipulation of nucleic acids
encoding BTLA and B7x proteins disclosed herein.
[0165] In one aspect, the present invention provides B7x nucleic
acids, including B7x nucleic acids encoding B7x proteins.
[0166] In another aspect, the present invention provides BTLA
nucleic acids, including BTLA nucleic acids encoding B7x
proteins.
[0167] By "nucleic acid" or oligonucleotide or grammatical
equivalents herein means at least two nucleotides covalently linked
together. A nucleic acid of the present invention will generally
contain phosphodiester bonds, although in some cases, as outlined
herein, particularly with respect to antisense nucleic acids or
probes, nucleic acid analogs are included that may have alternate
backbones, comprising, for example, phosphoramide (Beaucage, et
al., Tetrahedron, 49(10):1925 (1993) and references therein;
Letsinger, J. Org. Chem., 35:3800 (1970); Sprinzl, et al., Eur. J.
Biochem., 81:579 (1977); Letsinger, et al., Nucl. Acids Res.,
14:3487 (1986); Sawai, et al., Chem. Lett., 805 (1984), Letsinger,
et al., J. Am. Chem. Soc., 110:4470 (1988); and Pauwels, et al.,
Chemica Scripta, 26:141 (1986)), phosphorothioate (Mag, et al.,
Nucleic Acids Res., 19:1437 (1991); and U.S. Pat. No. 5,644,048),
phosphorodithioate (Briu, et al., J. Am. Chem. Soc., 111:2321
(1989)), O-methylphosphoroamidite linkages (see Eckstein,
Oligonucleotides and Analogues: A Practical Approach, Oxford
University Press), and peptide nucleic acid backbones and linkages
(see Egholm, J. Am. Chem. Soc., 114:1895 (1992); Meier, et al.,
Chem. Int. Ed. Engl., 31:1008 (1992); Nielsen, Nature, 365:566
(1993); Carlsson, et al., Nature, 380:207 (1996), all of which are
incorporated by reference)). Other analog nucleic acids include
those with positive backbones (Denpcy, et al., Proc. Natl. Acad.
Sci. USA, 92:6097 (1995)); non-ionic backbones (U.S. Pat. Nos.
5,386,023; 5,637,684; 5,602,240; 5,216,141; and 4,469,863;
Kiedrowshi, et al., Angew. Chem. Intl. Ed. English, 30:423 (1991);
Letsinger, et al., J. Am. Chem. Soc., 110:4470 (1988); Letsinger,
et al., Nucleoside & Nucleotide, 13:1597 (1994); Chapters 2 and
3, ASC Symposium Series 580, "Carbohydrate Modifications in
Antisense Research", Ed. Y. S. Sanghui and P. Dan Cook; Mesmaeker,
et al., Bioorganic & Medicinal Chem. Lett., 4:395 (1994);
Jeffs, et al., J. Biomolecular NMR, 34:17 (1994); Tetrahedron
Lett., 37:743 (1996)) and non-ribose backbones, including those
described in U.S. Pat. Nos. 5,235,033 and 5,034,506, and Chapters 6
and 7, ASC Symposium Series 580, "Carbohydrate Modifications in
Antisense Research", Ed. Y. S. Sanghui and P. Dan Cook. Nucleic
acids containing one or more carbocyclic sugars, as well as "locked
nucleic acids", are also included within the definition of nucleic
acids (see Jenkins, et al., Chem. Soc. Rev., (1995) pp. 169-176).
Several nucleic acid analogs are described in Rawls, C & E
News, Jun. 2, 1997, page 35. All of these references are hereby
expressly incorporated by reference. These modifications of the
ribose-phosphate backbone may be done to facilitate the addition of
additional moieties such as labels, or to increase the stability
and half-life of such molecules in physiological environments. In
addition, mixtures of naturally occurring nucleic acids and analogs
can be made. Alternatively, mixtures of different nucleic acid
analogs, and mixtures of naturally occurring nucleic acids and
analogs may be made. The nucleic acids may be single stranded or
double stranded, as specified, or contain portions of both double
stranded or single stranded sequence. The nucleic acid may be DNA,
both genomic and cDNA, RNA or a hybrid, where the nucleic acid
contains any combination of deoxyribo- and ribo-nucleotides, and
any combination of bases, including uracil, adenine, thymine,
cytosine, guanine, inosine, xathanine hypoxathanine, isocytosine,
isoguanine, etc.
[0168] With respect to nucleic acids that encode B7x and BTLA
proteins, it will be appreciated by those in the art, that due to
the degeneracy of the genetic code, an extremely large number of
nucleic acids may be made, all of which encode the B7x and BTLA
proteins of the present invention. Thus, having identified a
particular amino acid sequence, those skilled in the art could make
any number of different nucleic acids, by simply modifying the
sequence of one or more codons in a way which does not change the
amino acid sequence of the B7x or BTLA protein.
[0169] Included among B7x nucleic acids are allelic variants. A B7x
allelic variant refers to one of several possible naturally
occurring alternate forms of the B7x gene occupying a given locus
on a chromosome of an organism or a population of organisms. The
existence of naturally occurring alternate forms is referred to as
polymorphism. B7x nucleic acids also include splice variants. B7x
splice variant refers to a nucleic acid, usually RNA, which is
generated by alternative processing of intron sequences in an B7x
RNA transcript to produce alternate B7x proteins.
[0170] Included among BTLA nucleic acids are allelic variants. A
BTLA allelic variant refers to one of several possible naturally
occurring alternate forms of the BTLA gene occupying a given locus
on a chromosome of an organism or a population of organisms. The
existence of naturally occurring alternate forms is referred to as
polymorphism. As disclosed herein, BTLA polymorphism has been
observed in mice. BTLA nucleic acids also include splice variants.
BTLA splice variant refers to a nucleic acid, usually RNA, which is
generated by alternative processing of intron sequences in an BTLA
RNA transcript to produce alternate BTLA proteins. As disclosed
herein, presumed alternatively spliced forms of BTLA have been
identified.
[0171] In a preferred embodiment, the present invention provides
B7x nucleic acids encoding B7x proteins, which comprise a
nucleotide sequence having at least about 80%, more preferably at
least about 85%, more preferably at least about 90%, more
preferably at least about 95%, most preferably at least about 98%
identity to the nucleotide sequence set forth in FIG. 2 or FIG.
3.
[0172] In another preferred embodiment, the present invention
provides B7x nucleic acids encoding B7x proteins, which comprise a
nucleotide sequence encoding an amino acid sequence having at least
about 80%, more preferably at least about 85%, more preferably at
least about 90%, more preferably at least about 95%, most
preferably at least about 98% identity to one of the amino acid
sequence set forth in FIG. 1.
[0173] In a preferred embodiment, the present invention provides
B7x nucleic acids encoding a B7x protein, which nucleic acids are
about 1.9, 3.5, or 8.2 kb in size.
[0174] In another preferred embodiment, the present invention
provides B7x nucleic acids encoding a B7x protein, which nucleic
acids are about 3.2 kb in size.
[0175] In another preferred embodiment the present invention
provides BTLA nucleic acids encoding BTLA proteins, which comprise
a nucleotide sequence encoding an amino acid sequence having at
least about 80%, more preferably at least about 85%, more
preferably at least about 90%, more preferably at least about 95%,
most preferably at least about 98% identity to one of the amino
acid sequences set forth in FIG. 19.
[0176] In another preferred embodiment, the present invention
provides BTLA nucleic acids encoding BTLA proteins that lack the
protein sequence encoded by exon 2, and consequently lack the Ig
domain depicted in FIG. 21.
[0177] In a preferred embodiment, the present invention provides
B7x nucleic acids encoding B7x protein fragments described
herein.
[0178] In another preferred embodiment, the present invention
provides BTLA nucleic acids encoding BTLA protein fragments
described herein.
[0179] In some embodiments, B7x and BTLA nucleic acids are
determined through hybridization studies. Thus, for example,
nucleic acids which hybridize under high stringency conditions to
the nucleotide sequences set forth in the figures, or to those
which encode the amino acid sequences set forth in the figures, or
complements thereof, or fragments thereof or their complements, are
considered B7x or BTLA nucleic acids. High stringency conditions
are known in the art; see for example Sambrook et al., Molecular
Cloning, A Laboratory Manual, 3rd edition, 2001, Cold Spring Harbor
Press, Cold Spring Harbor, N.Y.; and Short Protocols in Molecular
Biology, ed. Ausubel, et al., both of which are hereby incorporated
by reference. Stringent conditions are sequence-dependent and will
be different in different circumstances. Longer sequences hybridize
specifically at higher temperatures. An extensive guide to the
hybridization of nucleic acids is found in Tijssen, Techniques in
Biochemistry and Molecular Biology--Hybridization with Nucleic Acid
Probes, "Overview of principles of hybridization and the strategy
of nucleic acid assays" (1993). Generally, stringent conditions are
selected to be about 5-10.degree. C. lower than the thermal melting
point (Tm) for the specific sequence at a defined ionic strength
pH. The Tm is the temperature (under defined ionic strength, pH and
nucleic acid concentration) at which 50% of the probes
complementary to the target hybridize to the target sequence at
equilibrium (as the target sequences are present in excess, at Tm,
50% of the probes are occupied at equilibrium). Stringent
conditions will be those in which the salt concentration is less
than about 1.0 sodium ion, typically about 0.01 to 1.0 M sodium ion
concentration (or other salts) at pH 7.0 to 8.3 and the temperature
is at least about 30.degree. C. for short probes (e.g. 10 to 50
nucleotides) and at least about 60.degree. C. for long probes (e.g.
greater than 50 nucleotides). Stringent conditions may also be
achieved with the addition of destabilizing agents such as
formamide.
[0180] In other embodiments, less stringent hybridization
conditions are used; for example, moderate or low stringency
conditions may be used, as are known in the art; see Sambrook et
al., Molecular Cloning, A Laboratory Manual, 3rd edition, 2001,
Cold Spring Harbor Press, Cold Spring Harbor, N.Y.; and Tijssen,
supra.
[0181] Also provided herein are B7x antisense nucleic acids which
will hybridize under high stringency conditions to a B7x nucleic
acid. In a preferred embodiment, the B7x antisense nucleic acid
inhibits expression of B7x protein. In a preferred embodiment, the
B7x antisense nucleic acid inhibits B7x protein activity.
[0182] Also provided herein are BTLA antisense nucleic acids which
will hybridize under high stringency conditions to a BTLA nucleic
acid encoding a BTLA protein. In a preferred embodiment, the BTLA
antisense nucleic acid inhibits expression of BTLA protein. In a
preferred embodiment, the BTLA antisense nucleic acid inhibits BTLA
protein activity.
[0183] As is known in the art, a number of different programs can
be used to identify whether a protein or nucleic acid has sequence
identity or similarity to a known sequence. For a detailed
discussion, see D. Mount, Bioinformatics, Cold Spring Harbor Press,
Cold Spring Harbor, N.Y., 2001, ISBN 0-87969-608-7. Sequence
identity and/or similarity is determined using standard techniques
known in the art, including, but not limited to, the local sequence
identity algorithm of Smith & Waterman, Adv. Appl. Math. 2:482
(1981), by the sequence identity alignment algorithm of Needleman
& Wunsch, J. Mol. Biol. 48:443 (1970), by the search for
similarity method of Pearson & Lipman, PNAS USA 85:2444 (1988),
by computerized implementations of these algorithms (GAP, BESTFIT,
FASTA, and TFASTA in the Wisconsin Genetics Software Package,
Genetics Computer Group, 575 Science Drive, Madison, Wis.), the
Best Fit sequence program described by Devereux et al., Nucl. Acid
Res. 12:387-395 (1984), preferably using the default settings, or
by inspection. Preferably, percent identity is calculated by FastDB
based upon the following parameters: mismatch penalty of 1; gap
penalty of 1; gap size penalty of 0.33; and joining penalty of 30,
"Current Methods in Sequence Comparison and Analysis,"
Macromolecule Sequencing and Synthesis, Selected Methods and
Applications, pp 127-149 (1988), Alan R. Liss, Inc.
[0184] An example of a useful algorithm is PILEUP. PILEUP creates a
multiple sequence alignment from a group of related sequences using
progressive, pairwise alignments. It can also plot a tree showing
the clustering relationships used to create the alignment. PILEUP
uses a simplification of the progressive alignment method of Feng
& Doolittle, J. Mol. Evol. 35:351-360 (1987); the method is
similar to that described by Higgins & Sharp CABIOS 5:151-153
(1989). Useful PILEUP parameters including a default gap weight of
3.00, a default gap length weight of 0.10, and weighted end gaps.
Another example of a useful algorithm is the BLAST algorithm,
described in Altschul et al., J. Mol. Biol. 215, 403-410, (1990)
and Karlin et al., PNAS USA 90:5873-5787 (1993). A particularly
useful BLAST program is the WU-BLAST-2 program which was obtained
from Altschul et al., Methods in Enzymology, 266: 460-480 (1996).
WU-BLAST-2 uses several search parameters, most of which are set to
the default values. The adjustable parameters are set with the
following values: overlap span=1, overlap fraction=0.125, word
threshold (T)=11. The HSP S and HSP S2 parameters are dynamic
values and are established by the program itself depending upon the
composition of the particular sequence and composition of the
particular database against which the sequence of interest is being
searched; however, the values may be adjusted to increase
sensitivity.
[0185] An additional useful algorithm is gapped BLAST as reported
by Altschul et al. Nucleic Acids Res. 25:3389-3402. Gapped BLAST
uses BLOSUM-62 substitution scores; threshold T parameter set to 9;
the two-hit method to trigger ungapped extensions; charges gap
lengths of k a cost of 10+k; X.sub.u set to 16, and X.sub.g set to
40 for database search stage and to 67 for the output stage of the
algorithms. Gapped alignments are triggered by a score
corresponding to .about.22 bits. A percent amino acid sequence
identity value is determined by the number of matching identical
residues divided by the total number of residues of the longer
sequence in the aligned region. The longer sequence is the one
having the most actual residues in the aligned region (gaps
introduced by WU-Blast-2 to maximize the alignment score are
ignored).
[0186] The alignment may include the introduction of gaps in the
sequences to be aligned. In addition, for sequences which contain
either more or fewer amino acids than the protein sequences set
forth in the figures, it is understood that in one embodiment, the
percentage of sequence identity will be determined based on the
number of identical amino acids in relation to the total number of
amino acids. Thus, for example, the percent sequence identity of
sequences shorter than those shown in the figures will be
determined using the number of amino acids in the shorter sequence,
in one embodiment. In percent identity calculations relative weight
is not assigned to various manifestations of sequence variation,
such as, insertions, deletions, substitutions, etc.
[0187] In one embodiment, only identities are scored positively
(+1) and all forms of sequence variation including gaps are
assigned a value of 0, which obviates the need for a weighted scale
or parameters as described below for sequence similarity
calculations. Percent sequence identity can be calculated, for
example, by dividing the number of matching identical residues by
the total number of residues of the shorter sequence in the aligned
region and multiplying by 100. The longer sequence is the one
having the most actual residues in the aligned region.
[0188] In a similar manner, percent (%) nucleic acid sequence
identity is defined as the percentage of nucleotide residues in a
candidate sequence that are identical with the nucleotide residues
in the B7x nucleic acid set forth in FIG. 2 or 4, or a BTLA nucleic
acid sequence encoding a BTLA amino acid sequence set forth in FIG.
19. A preferred method utilizes the BLASTN module of WU-BLAST-2 set
to the default parameters, with overlap span and overlap fraction
set to 1 and 0.125, respectively.
[0189] As will be appreciated by those skilled in the art, the
sequences of the present invention may contain sequencing errors.
That is, there may be incorrect nucleosides, frameshifts, unknown
nucleosides, or other types of sequencing errors in any of the
sequences; however, the correct sequences will fall within the
homology and stringency definitions herein.
[0190] B7x and BTLA proteins of the present invention may be
shorter or longer than the amino acid sequences set forth in the
figures, or encoded by the nucleic acid sequences set forth in the
figures.
[0191] In one embodiment herein, fragments of B7x proteins are
considered B7x proteins if a) they share at least one antigenic
epitope; b) have at least the indicated sequence identity; c) and
preferably have B7x protein activity as further defined herein.
[0192] Similarly, fragments of BTLA proteins are considered BTLA
proteins if a) they share at least one antigenic epitope; b) have
at least the indicated sequence identity; c) and preferably have
BTLA protein activity as further defined herein.
[0193] The nucleic acids of the present invention may also be
shorter or longer than those shown in the figures, or those
encoding the amino acid sequences shown in the figures. In some
cases, where a sequence is used diagnostically, that is, when the
presence or absence of a B7x or a BTLA nucleic acid is determined,
only the indicated sequence identity is required. The nucleic acid
fragments provided herein include nucleic acids consisting
essentially of portions of the sequences provided herein that have
not been exactly identified previously; fragments having sequences
with the indicated sequence identity to that portion not previously
identified are also provided in an embodiment herein.
[0194] In addition, as is more fully outlined below, B7x and BTLA
proteins can be made that are longer than those depicted in the
figures, for example, by the addition of epitope or purification
tags, the addition of other fusion sequences, or the elucidation of
additional coding and non-coding sequences. As described below, the
fusion of a B7x or BTLA protein to a fluorescent protein, such as
Blue Fluorescent Protein (BFP) or Green Fluorescent Protein (GFP),
is preferred in one embodiment. In a highly preferred embodiment, a
B7x or BTLA protein, or fragment thereof, is fused to the constant
region of an immunoglobulin, thereby creating a B7x-Ig or BTLA-Ig
fusion protein.
[0195] The B7x and BTLA proteins and nucleic acids of the present
invention are preferably recombinant. As used herein and further
defined below, nucleic acid may refer to either DNA or RNA, or
molecules which contain both deoxy- and ribonucleotides. The
nucleic acids include genomic DNA, cDNA and oligonucleotides
including sense and anti-sense nucleic acids. Such nucleic acids
may also contain modifications in the ribose-phosphate backbone to
increase stability and half life of such molecules in physiological
environments.
[0196] The nucleic acid may be double stranded, single stranded, or
contain portions of both double stranded and single stranded
sequence. As will be appreciated by those in the art, the depiction
of a single strand ("Watson") also defines the sequence of the
other strand ("Crick"); thus the sequences depicted in the figures
also include the complement of the sequence.
[0197] By the term recombinant nucleic acid herein is meant nucleic
acid, originally formed in vitro, in general, by the manipulation
of nucleic acid by endonucleases, in a form not normally found in
nature. Thus an isolated B7x or BTLA nucleic acid, in a linear
form, or an expression vector formed in vitro by ligating DNA
molecules that are not normally joined, are both considered
recombinant for the purposes of this invention. It is understood
that once a recombinant nucleic acid is made and reintroduced into
a host cell or organism, it will replicate non-recombinantly, i.e.
using the in vivo cellular machinery of the host cell rather than
in vitro manipulations; however, such nucleic acids, once produced
recombinantly, although subsequently replicated non-recombinantly,
are still considered recombinant for the purposes of the
invention.
[0198] Similarly, a recombinant protein is a protein made using
recombinant techniques, i.e. through the expression of a
recombinant nucleic acid as depicted above. A recombinant protein
is distinguished from naturally occurring protein by at least one
or more characteristics. For example, the protein may be isolated
or purified away from some or all of the proteins and compounds
with which it is normally associated in its wild type host, and
thus may be substantially pure. For example, an isolated protein is
unaccompanied by at least some of the material with which it is
normally associated in its natural state, preferably constituting
at least about 0.5%, more preferably at least about 5% by weight of
the total protein in a given sample. A substantially pure protein
comprises at least about 75% by weight of the total protein, with
at least about 80% being preferred, and at least about 90% being
particularly preferred. The definition includes the production of a
B7x and BTLA proteins from one organism in a different organism or
host cell. Alternatively, the protein may be made at a
significantly higher concentration than is normally seen, through
the use of a inducible promoter or high expression promoter, such
that the protein is made at increased concentration levels.
Alternatively, the protein may be in a form not normally found in
nature, as in the addition of an epitope tag, or amino acid
substitutions, insertions and deletions, as discussed below.
[0199] An isolated polypeptide refers to a polypeptide of the
invention that (1) has been separated from at least about 50% of
polynucleotide, lipid, carbohydrate, or other material with which
it is naturally found when isolated from a source cell, (2) is not
linked (by covalent or noncovalent interaction) to all or a portion
of a polypeptide to which the isolated polypeptide is linked in
nature, (3) is operably linked (by covalent or noncovalent
interaction) to a polypeptide with which it is not linked in
nature, or (4) does not occur in nature. Preferably, the isolated
polypeptide is substantially free from any other contaminating
polypeptides or other contaminants that are found in its natural
environment that would interfere with its therapeutic, diagnostic,
prohylactic or research use.
[0200] In a preferred embodiment, the present invention provides
B7x protein variants. In another preferred embodiment, the
invention provides BTLA protein variants. These variants fall into
one or more of three classes: substitutional, insertional or
deletional variants. These variants ordinarily are prepared by site
specific mutagenesis of nucleotides in the DNA encoding a B7x or
BTLA protein, using cassette or PCR mutagenesis or other techniques
well known in the art, to produce DNA encoding the variant, and
thereafter expressing the DNA in recombinant cell culture as
outlined above. However, variant protein fragments having up to
about 100-150 residues may be prepared by in vitro synthesis using
established techniques. Amino acid sequence variants are
characterized by the predetermined nature of the variation, a
feature that sets them apart from naturally occurring allelic or
interspecies B7x or BTLA proteins. The variants typically exhibit
the same qualitative biological activity as the naturally occurring
analogue, although variants can also be selected which have
modified characteristics, as will be more fully outlined below.
[0201] In an especially preferred embodiment, the invention
provides B7x variants that exhibit an elevated B7x bioactivity as
compared to the activity of B7x proteins set forth in FIG. 1.
[0202] In another especially preferred embodiment, the invention
provides BTLA variants that exhibit an elevated BTLA bioactivity as
compared to the activity of BTLA proteins set forth in FIG. 19.
[0203] While the site or region for introducing an amino acid
sequence variation is predetermined, the mutation per se need not
be predetermined. For example, in order to optimize the performance
of a mutation at a given site, random mutagenesis may be conducted
at the target codon or region and the expressed protein variants
screened for the optimal combination of desired activity.
Techniques for making substitution mutations at predetermined sites
in DNA having a known sequence are well known, for example, M13
primer mutagenesis and PCR mutagenesis. Screening of the mutants
may be done using assays that measure B7x or BTLA activity, as
described herein.
[0204] In an especially preferred embodiment, B7x variant proteins
are screened for their ability to modulate T-lymphocyte activation
as described herein.
[0205] In another especially preferred embodiment, B7x variant
proteins are screened for their ability to bind BTLA protein.
[0206] In another especially preferred embodiment, BTLA variant
proteins are screened for their ability to modulate T cell
activation as described herein.
[0207] In another especially preferred embodiment, BTLA variant
proteins are screened for their ability to bind B7x protein.
[0208] Amino acid substitutions are typically of single residues;
insertions usually will be on the order of from about 1 to 20 amino
acids, although considerably larger insertions may be tolerated.
Deletions range from about 1 to about 20 residues, although in some
cases deletions may be much larger. Substitutions, deletions,
insertions or any combination thereof may be used to arrive at a
final derivative. Generally these changes are done on a few amino
acids to minimize the alteration of the molecule. However, larger
changes may be tolerated in certain circumstances. When small
alterations in the characteristics of the B7x protein are desired,
substitutions are generally made in accordance with the following
chart:
TABLE-US-00001 CHART 1 Original residue Exemplary Substitutions Ala
Ser Arg Lys Asn Gln, His Asp Glu Cys Ser Gln Asn Glu Asp Gly Pro
His Asn, Gln Ile Leu, Val Leu Ile, Val Lys Arg, Gln Glu Met Leu,
Ile Phe Met, Leu, Tyr Ser Thr Thr Ser Trp Tyr Tyr Trp, Phe Val Ile,
Leu
[0209] Substantial changes in function or immunological identity
are made by selecting substitutions that are less conservative than
those shown in Chart 1. For example, substitutions may be made
which more significantly affect: the structure of the polypeptide
backbone in the area of the alteration, for example the
alpha-helical or beta-sheet structure; the charge or hydrophobicity
of the molecule at the target site; or the bulk of the side chain.
The substitutions which in general are expected to produce the
greatest changes in the polypeptide's properties are those in which
(a) a hydrophilic residue, e.g. seryl or threonyl, is substituted
for (or by) a hydrophobic residue, e.g. leucyl, isoleucyl,
phenylalanyl, valyl or alanyl; (b) a cysteine or proline is
substituted for (or by) any other residue; (c) a residue having an
electropositive side chain, e.g. lysyl, arginyl, or histidyl, is
substituted for (or by) an electronegative residue, e.g. glutamyl
or aspartyl; or (d) a residue having a bulky side chain, e.g.
phenylalanine, is substituted for (or by) one not having a side
chain, e.g. glycine.
[0210] The variants typically exhibit the same qualitative
biological activity and will elicit the same immune response as the
naturally-occurring analogue, although variants also are selected
to modify the characteristics of the B7x and BTLA proteins as
needed. The variant may be designed such that the biological
activity of the B7x or BTLA protein is altered. For example,
glycosylation sites may be altered or removed.
[0211] Covalent modifications of BTLA and B7x polypeptides are
included within the scope of this invention. One type of covalent
modification includes reacting targeted amino acid residues of a
B7x or BTLA polypeptide with an organic derivatizing agent that is
capable of reacting with selected side chains or the N- or
C-terminal residues of the polypeptide. Derivatization with
bifunctional agents is useful, for instance, for crosslinking B7x
or BTLA to a water-insoluble support matrix or surface for use in a
method for purifying anti-B7x or anti-BTLA antibodies, or screening
assays, as is more fully described below. Commonly used
crosslinking agents include, e.g.,
1,1-bis(diazoacetyl)-2-phenylethane, glutaraldehyde,
N-hydroxysuccinimide esters, for example, esters with
4-azidosalicylic acid, homobifunctional imidoesters, including
disuccinimidyl esters such as
3,3'-dithiobis(succinimidylpropionate), bifunctional maleimides
such as bis-N-maleimido-1,8-octane and agents such as
methyl-3-[(p-azidophenyl)dithio]propioimidate.
[0212] Other modifications include deamidation of glutaminyl and
asparaginyl residues to the corresponding glutamyl and aspartyl
residues, respectively, hydroxylation of proline and lysine,
phosphorylation of hydroxyl groups of seryl or threonyl residues,
methylation of the amino groups of lysine, arginine, and histidine
side chains [T. E. Creighton, Proteins: Structure and Molecular
Properties, W.H. Freeman & Co., San Francisco, pp. 79-86
(1983)], acetylation of the N-terminal amine, and amidation of any
C-terminal carboxyl group.
[0213] Another type of covalent modification of B7x and BTLA
polypeptides included within the scope of this invention comprises
altering the native glycosylation pattern of the polypeptide.
Altering the native glycosylation pattern is intended for purposes
herein to mean deleting one or more carbohydrate moieties found in
the native sequence of B7x or BTLA polypeptide, and/or adding one
or more glycosylation sites that are not present in the native
sequence.
[0214] Addition of glycosylation sites to B7x or BTLA polypeptides
may be accomplished by altering the amino acid sequence thereof.
The alteration may be made, for example, by the addition of, or
substitution by, one or more serine or threonine residues to the
native polypeptide sequence (for O-linked glycosylation sites). The
B7x or BTLA amino acid sequence may optionally be altered through
changes at the DNA level, particularly by mutating the DNA encoding
the polypeptide at preselected bases such that codons are generated
that will translate into the desired amino acids.
[0215] Another means of increasing the number of carbohydrate
moieties on the B7x or BTLA polypeptide is by chemical or enzymatic
coupling of glycosides to the polypeptide. Such methods are
described in the art, e.g., in WO 87/05330 published 11 Sep. 1987,
and in Aplin and Wriston, CRC Crit. Rev. Biochem., pp. 259-306
(1981).
[0216] Removal of carbohydrate moieties present on a B7x or BTLA
polypeptide may be accomplished chemically or enzymatically or by
mutational substitution of codons encoding for amino acid residues
that serve as targets for glycosylation. Chemical deglycosylation
techniques are known in the art and described, for instance, by
Hakimuddin, et al., Arch. Biochem. Biophys., 259:52 (1987) and by
Edge et al., Anal. Biochem., 118:131 (1981). Enzymatic cleavage of
carbohydrate moieties on polypeptides can be achieved by the use of
a variety of endo- and exo-glycosidases as described by Thotakura
et al., Meth. Enzymol., 138:350 (1987).
[0217] Another type of covalent modification of B7x and BTLA
protein contemplated by the invention comprises linking the
polypeptide to one of a variety of nonproteinaceous polymers, e.g.,
polyethylene glycol, polypropylene glycol, or polyoxyalkylenes, in
the manner set forth in U.S. Pat. No. 4,640,835; 4,496,689;
4,301,144; 4,670,417; 4,791,192 or 4,179,337.
[0218] B7x and BTLA polypeptides of the present invention may also
be modified in a way to form chimeric molecules comprising a B7x or
BTLA polypeptide fused to another, heterologous polypeptide or
amino acid sequence. In one embodiment, such a chimeric molecule
comprises a fusion of a B7x or BTLA polypeptide with a tag
polypeptide which provides an epitope to which an anti-tag antibody
can selectively bind. In a preferred embodiment, such a tag is the
"flag tag" described below. The epitope tag is generally placed at
the amino- or carboxyl-terminus of the B7x or BTLA polypeptide. The
presence of such epitope-tagged forms of polypeptide can be
detected using an antibody against the tag. Also, provision of the
epitope tag enables the B7x or BTLA polypeptide to be readily
purified by affinity purification using an anti-tag antibody or
another type of affinity matrix that binds to the epitope tag. In
an alternative embodiment, the chimeric molecule may comprise a
fusion of a B7x or BTLA polypeptide with an immunoglobulin or a
particular region of an immunoglobulin. For a bivalent form of the
chimeric molecule, such a fusion could be to the Fc region of an
IgG molecule as discussed further below.
[0219] Various tag polypeptides and their respective antibodies are
well known in the art. Examples include poly-histidine (poly-his)
or poly-histidine-glycine (poly-his-gly) tags; the flu HA tag
polypeptide and its antibody 12CA5 [Field et al., Mol. Cell. Biol.,
8:2159-2165 (1988)]; the c-myc tag and the 8F9, 3C7, 6E10, G4, B7
and 9E10 antibodies thereto [Evan et al., Molecular and Cellular
Biology, 5:3610-3616 (1985)]; and the Herpes Simplex virus
glycoprotein D (gD) tag and its antibody [Paborsky et al., Protein
Engineering, 3(6):547-553 (1990)]. Other tag polypeptides include
the Flag-peptide [Hopp et al., BioTechnoloov, 6:1204-1210 (1988)];
the KT3 epitope peptide [Martin et al., Science, 255:192-194
(1992)]; tubulin epitope peptide [Skinner et al., J. Biol. Chem.,
266:15163-15166 (1991)]; and the T7 gene 10 protein peptide tag
[Lutz-Freyermuth et al., Proc. Natl. Acad. Sci. USA, 87:6393-6397
(1990)].
[0220] In some embodiments herein, B7x or BTLA protein family
members and B7x or BTLA proteins from other organisms are cloned
and expressed as outlined below. Thus, probe or degenerate
polymerase chain reaction (PCR) primer sequences may be used to
find other related B7x and BTLA proteins from humans or other
organisms. As will be appreciated by those in the art, particularly
useful probe and/or PCR primer sequences include the unique areas
of B7x and BTLA nucleic acid sequences. As is generally known in
the art, preferred PCR primers are from about 15 to about 35
nucleotides in length, with from about 20 to about 30 being
preferred, and may contain inosine as needed. The conditions for
the PCR reaction are well known in the art. It is therefore also
understood that provided along with the sequences in the sequences
listed herein are portions of those sequences, wherein unique
portions of 15 nucleotides or more are particularly preferred. The
skilled artisan can routinely synthesize or cut a nucleotide
sequence to the desired length.
[0221] Once isolated from its natural source, e.g., contained
within a plasmid or other vector or excised therefrom as a linear
nucleic acid segment, the recombinant B7x and BTLA nucleic acids
can be further used as probes to identify and isolate other B7x and
BTLA nucleic acids. They can also be used as precursor nucleic
acids to make modified or variant nucleic acids and proteins.
[0222] Using the nucleic acids of the present invention, a variety
of expression vectors are made. The expression vectors may be
either self-replicating extrachromosomal vectors or vectors which
integrate into a host genome. Generally, these expression vectors
include transcriptional and translational regulatory nucleic acid
operably linked to a nucleic acid encoding a B7x or BTLA protein.
The term control sequences refers to DNA sequences necessary for
the expression of an operably linked coding sequence in a
particular host organism. The control sequences that are suitable
for prokaryotes, for example, include a promoter, optionally an
operator sequence, and a ribosome binding site. Eukaryotic cells
are known to utilize promoters, polyadenylation signals, and
enhancers.
[0223] Nucleic acid is operably linked when it is placed into a
functional relationship with another nucleic acid sequence. For
example, DNA for a presequence or secretory leader is operably
linked to DNA for a polypeptide if it is expressed as a preprotein
that participates in the secretion of the polypeptide; a promoter
or enhancer is operably linked to a coding sequence if it affects
the transcription of the sequence; or a ribosome binding site is
operably linked to a coding sequence if it is positioned so as to
facilitate translation. As another example, operably linked refers
to DNA sequences linked so as to be contiguous, and, in the case of
a secretory leader, contiguous and in reading phase. However,
enhancers do not have to be contiguous. Linking is accomplished by
ligation at convenient restriction sites. If such sites do not
exist, the synthetic oligonucleotide adaptors or linkers are used
in accordance with conventional practice. The transcriptional and
translational regulatory nucleic acid will generally be appropriate
to the host cell used to express the B7x or BTLA protein; for
example, transcriptional and translational regulatory nucleic acid
sequences from Bacillus are preferably used to express protein in
Bacillus. Numerous types of appropriate expression vectors, and
suitable regulatory sequences are known in the art for a variety of
host cells.
[0224] In general, the transcriptional and translational regulatory
sequences may include, but are not limited to, promoter sequences,
ribosomal binding sites, transcriptional start and stop sequences,
translational start and stop sequences, and enhancer or activator
sequences. In a preferred embodiment, the regulatory sequences
include a promoter and transcriptional start and stop
sequences.
[0225] Promoter sequences encode either constitutive or inducible
promoters. The promoters may be either naturally occurring
promoters or hybrid promoters. Hybrid promoters, which combine
elements of more than one promoter, are also known in the art, and
are useful in the present invention. In addition, the expression
vector may comprise additional elements. For example, the
expression vector may have two replication systems, thus allowing
it to be maintained in two organisms, for example in mammalian or
insect cells for expression and in a prokaryotic host for cloning
and amplification. Furthermore, for integrating expression vectors,
the expression vector contains at least one sequence homologous to
the host cell genome, and preferably two homologous sequences which
flank the expression construct. The integrating vector may be
directed to a specific locus in the host cell by selecting the
appropriate homologous sequence for inclusion in the vector.
Constructs for integrating vectors are well known in the art.
[0226] In addition, in a preferred embodiment, the expression
vector contains a selectable marker gene to allow the selection of
transformed host cells. Selection genes are well known in the art
and will vary with the host cell used.
[0227] B7x and BTLA proteins of the present invention may be
produced by culturing a host cell transformed with an expression
vector containing a B7x or BTLA nucleic acid encoding a B7x or BTLA
protein, respectively, under the appropriate conditions to induce
or cause expression of the protein. The conditions appropriate for
B7x or BTLA protein expression will vary with the choice of the
expression vector and the host cell, and will be easily ascertained
by one skilled in the art through routine experimentation. For
example, the use of constitutive promoters in the expression vector
will require optimizing the growth and proliferation of the host
cell, while the use of an inducible promoter requires the
appropriate growth conditions for induction. In addition, in some
embodiments, the timing of the harvest is important. For example,
the baculoviral systems used in insect cell expression are lytic
viruses, and thus harvest time selection can be crucial for product
yield.
[0228] Appropriate host cells include yeast, bacteria,
archebacteria, fungi, and insect and animal cells, including
mammalian cells. Of particular interest are Drosophila melangaster
cells, Saccharomyces cerevisiae and other yeasts, E. coli, Bacillus
subtilis, SF9 cells, C129 cells, 293 cells, Neurospora, BHK, CHO,
COS, and HeLa cells, fibroblasts, Schwanoma cell lines,
immortalized mammalian myeloid and lymphoid cell lines such as
Jurkat and BJAB cells.
[0229] In a preferred embodiment, B7x and BTLA proteins are
expressed in mammalian cells. Mammalian expression systems are also
known in the art, and include retroviral systems. A mammalian
promoter is any DNA sequence capable of binding mammalian RNA
polymerase and initiating the downstream (3') transcription of a
coding sequence for B7x or BTLA into mRNA. A promoter will have a
transcription initiating region, which is usually placed proximal
to the 5' end of the coding sequence, and a TATA box, using a
located 25-30 base pairs upstream of the transcription initiation
site. The TATA box is thought to direct RNA polymerase II to begin
RNA synthesis at the correct site. A mammalian promoter will also
contain an upstream promoter element (enhancer element), typically
located within 100 to 200 base pairs upstream of the TATA box. An
upstream promoter element determines the rate at which
transcription is initiated and can act in either orientation. Of
particular use as mammalian promoters are the promoters from
mammalian viral genes, since the viral genes are often highly
expressed and have a broad host range. Examples include the SV40
early promoter, mouse mammary tumor virus LTR promoter, adenovirus
major late promoter, herpes simplex virus promoter, and the CMV
promoter.
[0230] Typically, transcription termination and polyadenylation
sequences recognized by mammalian cells are regulatory regions
located 3' to the translation stop codon and thus, together with
the promoter elements, flank the coding sequence. The 3' terminus
of the mature mRNA is formed by site-specific post-translational
cleavage and polyadenylation. Examples of transcription terminator
and polyadenlytion signals include those derived form SV40.
[0231] The methods of introducing exogenous nucleic acid into
mammalian hosts, as well as other hosts, are well known in the art,
and will vary with the host cell used. Techniques include
dextran-mediated transfection, calcium phosphate precipitation,
polybrene mediated transfection, protoplast fusion,
electroporation, viral infection, encapsulation of the
polynucleotide(s) in liposomes, and direct microinjection of the
DNA into nuclei.
[0232] In a preferred embodiment, B7x and BTLA proteins are
expressed in bacterial systems. Bacterial expression systems are
well known in the art.
[0233] A suitable bacterial promoter is any nucleic acid sequence
capable of binding bacterial RNA polymerase and initiating the
downstream (3') transcription of the coding sequence of B7x or BTLA
into mRNA. A bacterial promoter has a transcription initiation
region which is usually placed proximal to the 5' end of the coding
sequence. This transcription initiation region typically includes
an RNA polymerase binding site and a transcription initiation site.
Sequences encoding metabolic pathway enzymes provide particularly
useful promoter sequences. Examples include promoter sequences
derived from sugar metabolizing enzymes, such as galactose, lactose
and maltose, and sequences derived from biosynthetic enzymes such
as tryptophan. Promoters from bacteriophage may also be used and
are known in the art. In addition, synthetic promoters and hybrid
promoters are also useful; for example, the tac promoter is a
hybrid of the trp and lac promoter sequences. Furthermore, a
bacterial promoter can include naturally occurring promoters of
non-bacterial origin that have the ability to bind bacterial RNA
polymerase and initiate transcription.
[0234] In addition to a functioning promoter sequence, an efficient
ribosome binding site is desirable. In E. coli, the ribosome
binding site is called the Shine-Delgarno (SD) sequence and
includes an initiation codon and a sequence 3-9 nucleotides in
length located 3-11 nucleotides upstream of the initiation
codon.
[0235] The expression vector may also include a signal peptide
sequence that provides for secretion of the B7x or BTLA protein in
bacteria. The signal sequence typically encodes a signal peptide
comprised of hydrophobic amino acids which direct the secretion of
the protein from the cell, as is well known in the art. The protein
is either secreted into the growth media (gram-positive bacteria)
or into the periplasmic space, located between the inner and outer
membrane of the cell (gram-negative bacteria).
[0236] The bacterial expression vector may also include a
selectable marker gene to allow for the selection of bacterial
strains that have been transformed. Suitable selection genes
include genes which render the bacteria resistant to drugs such as
ampicillin, chloramphenicol, erythromycin, kanamycin, neomycin and
tetracycline. Selectable markers also include biosynthetic genes,
such as those in the histidine, tryptophan and leucine biosynthetic
pathways.
[0237] These components are assembled into expression vectors.
Expression vectors for bacteria are well known in the art, and
include vectors for Bacillus subtilis, E. coli, Streptococcus
cremoris, and Streptococcus lividans, among others.
[0238] The bacterial expression vectors are transformed into
bacterial host cells using techniques well known in the art, such
as calcium chloride treatment, electroporation, and others.
[0239] In some embodiments, B7x or BTLA proteins are produced in
insect cells. Expression vectors for the transformation of insect
cells, and in particular, baculovirus-based expression vectors, are
well known in the art.
[0240] In a preferred embodiment, a B7x or BTLA protein is produced
in yeast cells. Yeast expression systems are well known in the art,
and include expression vectors for Saccharomyces cerevisiae,
Candida albicans and C. maltosa, Hansenula polymorpha,
Kluyveromyces fragilis and K. lactis, Pichia guillerimondii and P.
pastoris, Schizosaccharomyces pombe, and Yarrowia lipolytica.
[0241] Preferred promoter sequences for expression in yeast include
the inducible GAL1,10 promoter, the promoters from alcohol
dehydrogenase, enolase, glucokinase, glucose-6-phosphate isomerase,
glyceraldehyde-1-phosphate-dehydrogenase, hexokinase,
phosphofructokinase, 3-phosphoglycerate mutase, pyruvate kinase,
and the acid phosphatase gene. Yeast selectable markers include
ADE2, HIS4, LEU2, TRP1, and ALG7, which confers resistance to
tunicamycin; the neomycin phosphotransferase gene, which confers
resistance to G418; and the CUP1 gene, which allows yeast to grow
in the presence of copper ions.
[0242] B7x and BTLA proteins may also be made as fusion proteins,
using techniques well known in the art. Thus, for example, for the
creation of monoclonal antibodies, if the desired epitope is small,
the B7x or BTLA protein may be fused to a carrier protein to form
an immunogen. Alternatively, the B7x or BTLA protein may be made as
a fusion protein to increase expression, or for other reasons. For
example, when the B7x or BTLA protein is a peptide, the nucleic
acid encoding the peptide may be linked to other nucleic acid for
expression purposes. Similarly, B7x and BTLA proteins of the
invention can be linked to protein labels, such as green
fludrescent protein (GFP), red fluorescent protein (RFP), blue
fluorescent protein (BFP), yellow fluorescent protein (YFP),
etc.
[0243] In some embodiments, the B7x or BTLA nucleic acids, and/or
proteins, and/or antibodies of the invention are labeled. By
labeled herein is meant that a compound has at least one element,
isotope or chemical compound attached to enable the detection of
the compound. In general, labels fall into four classes: a)
isotopic labels, which may be radioactive or heavy isotopes; b)
immune labels, which may be antibodies or antigens; c) colored or
fluorescent dyes; d) magnetic moieties. The labels may be
incorporated into the compound at any position.
[0244] In a preferred embodiment, a B7x or BTLA protein is purified
or isolated after expression. B7x and BTLA proteins may be isolated
or purified in a variety of ways known to those skilled in the art
depending on what other components are present in the sample.
Standard purification methods include electrophoretic, molecular,
immunological and chromatographic techniques, including ion
exchange, hydrophobic, affinity, and reverse-phase HPLC
chromatography, and chromatofocusing. For example, the B7x protein
may be purified using a standard anti-B7x antibody column.
[0245] Ultrafiltration and diafiltration techniques, in conjunction
with protein concentration, are also useful. For general guidance
in suitable purification techniques, see Scopes, R., Protein
Purification, Springer-Verlag, NY (1982). The degree of
purification necessary will vary depending on the use of the B7x or
BTLA protein. In some instances no purification will be
necessary.
[0246] Once expressed, and purified if necessary, the B7x and BTLA
proteins and nucleic acids are also useful in a number of
applications.
[0247] The nucleotide sequences (or their complement) encoding BTLA
and B7x proteins have various applications in the art of molecular
biology, including uses as hybridization probes, in chromosome and
gene mapping and in the generation of anti-sense RNA and DNA. These
nucleic acids are also useful for the preparation of B7x and BTLA
proteins by the recombinant techniques described herein.
[0248] The full-length native sequence of the B7x or BTLA gene, or
portions thereof, may be used as a hybridization probe for a cDNA
library to isolate other genes (for example, allelic variants or
species variants) which have a desired sequence identity to the B7x
or BTLA nucleic acids. Optionally, the length of the probes will be
about 20 to about 50 bases. The hybridization probes may be derived
from the nucleotide sequences herein or from genomic sequences
including promoters, enhancer elements and introns of native
sequences as provided herein. By way of example, a screening method
will comprise isolating the coding region of the B7x gene using the
known DNA sequence to synthesize a selected probe of about 40
bases. Hybridization probes may be labeled by a variety of labels,
including radionucleotides such as 32P or 35S, or enzymatic labels
such as alkaline phosphatase coupled to the probe via avidin/biotin
coupling systems. Labeled probes having a sequence complementary to
that of the B7x gene of the present invention can be used to screen
libraries of human cDNA, genomic DNA or mRNA to determine which
members of such libraries the probe hybridizes.
[0249] Nucleotide sequences encoding a B7x of BTLA protein can also
be used to construct hybridization probes for mapping genes that
encode B7x or BTLA proteins, and for the genetic analysis of
individuals with B7x- or BTLA-related genetic disorders. The
nucleotide sequences provided herein may be mapped to a chromosome
and specific regions of a chromosome using known techniques, such
as in situ hybridization, linkage analysis against known
chromosomal markers, and hybridization screening with
libraries.
[0250] Nucleic acids which encode B7x or BTLA protein or modified
forms thereof can also be used to generate either transgenic
animals or "knock out" animals which, in turn, are useful in the
development and screening of therapeutically useful reagents. A
transgenic animal (e.g., a mouse or rat) is an animal having cells
that contain a transgene, which transgene was introduced into the
animal or an ancestor of the animal at a prenatal, e.g., an
embryonic stage. A transgene is a DNA which is integrated into the
genome of a cell from which a transgenic animal develops. In one
embodiment, cDNA encoding a B7x protein can be used to clone
genomic DNA encoding a B7x protein in accordance with established
techniques and the genomic sequences used to generate transgenic
animals that contain cells which express the desired DNA. Methods
for generating transgenic animals, particularly animals such as
mice or rats, have become conventional in the art and are
described, for example, in U.S. Pat. Nos. 4,736,866 and
4,870,009.
[0251] Alternatively, non-human homologues of the B7x or BTLA
protein can be used to construct a "knock out" animal which has a
defective or altered gene encoding either B7x or BTLA protein as a
result of homologous recombination between the endogenous gene and
an altered genomic DNA encoding B7x or BTLA, which is introduced
into an embryonic cell of the animal. For example, cDNA encoding a
B7x protein can be used to clone genomic DNA encoding a B7x protein
in accordance with established techniques. A portion of the genomic
DNA encoding a B7x protein can be deleted or replaced with another
gene, such as a gene encoding a selectable marker which can be used
to monitor integration. Typically, several kilobases of unaltered
flanking DNA (both at the 5' and 3' ends) are included in the
vector [see e.g., Thomas and Capecchi, Cell, 51:503 (1987) for a
description of homologous recombination vectors]. The vector is
introduced into an embryonic stem cell line (e.g., by
electroporation) and cells in which the introduced DNA has
homologously recombined with the endogenous DNA are selected [see
e.g., Li et al., Cell, 69:915 (1992)]. The selected cells are then
injected into a blastocyst of an animal (e.g., a mouse or rat) to
form aggregation chimeras [see e.g., Bradley, in Teratocarcinomas
and Embryonic Stem Cells: A Practical Approach, E. J. Robertson,
ed. (IRL, Oxford, 1987), pp. 113-152]. A chimeric embryo can then
be implanted into a suitable pseudopregnant female foster animal
and the embryo brought to term to create a "knock out" animal.
Progeny harboring the homologously recombined DNA in their germ
cells can be identified by standard techniques and used to breed
animals in which all cells of the animal contain the homologously
recombined DNA. Knockout animals can be characterized for instance,
for their ability to defend against certain pathological conditions
and for their development of pathological conditions due to absence
of the B7x protein.
[0252] It is understood that the models described herein can be
varied. For example, "knock-in" models can be formed, or the models
can be cell-based rather than animal models.
(II) Fusion Proteins
[0253] Variant polypeptides of the present invention may also be
fused to another, heterologous polypeptide or amino acid sequence
to form a chimera. In some embodiments, fusion proteins comprise
fusion partners comprising labels (e.g. autofluorescent proteins,
survival and/or selection proteins), stability and/or purification
sequences, toxins, or any other protein sequences of use.
Additional fusion partners are described below. In some instances,
the fusion partner is not a protein.
[0254] In another embodiment, a polypeptide of the invention is
fused with human serum albumin to improve pharmacokinetics.
[0255] In a further embodiment, a polypeptide of the invention is
fused to a cytotoxic agent. In this method, the polypeptide of the
invention acts to target the cytotoxic agent to cells, resulting in
a reduction in the number of afflicted cells. Cytotoxic agents
include, but are not limited to, diphtheria A chain, exotoxin A
chain, ricin A chain, abrin A chain, curcin, crotin, phenomycin,
enomycin and the like, as well as radiochemicals.
Peptide Tags
[0256] Various tag polypeptides and their respective antibodies are
well known in the art. Epitope tags may be placed at the amino- or
carboxyl-terminus of a polypeptide of the invention to enable
antibody detection. Also, the epitope tag enables a polypeptide of
the invention to be readily purified by affinity purification.
Examples of peptide tags include, but are not limited to,
poly-histidine (poly-His) or poly-histidine-glycine (poly-His-Gly)
tags; the flu HA tag polypeptide [Field et al., Mol. Cell. Biol.
8:2159-2165 (1988)]; the c-myc tag [Evan et al., Molecular and
Cellular Biology, 5:3610-3616 (1985)]; the Herpes Simplex virus
glycoprotein D (gD) tag [Paborsky et al., Protein Engineering, 3
(6):547-553 (1990)1 the Flag-peptide [Hopp et al., BioTechnology
6:1204-1210 (1988)]; the KT3 epitope peptide [Martin et al.,
Science 255:192-194 (1992)]; tubulin epitope peptide [Skinner et
al., J. Biol. Chem. 266:15163-15166 (1991)]; and the T7 gene 10
protein peptide tag [Lutz-Freyermuth et al., Proc. Natl. Acad. Sci.
U.S.A. 87:6393-6397 (1990)].
Labels
[0257] In one embodiment, a polypeptide of the invention is
modified by the addition of one or more labels. For example, labels
that may be used are well known in the art and include but are not
limited to biotin, tag and fluorescent labels (e.g. fluorescein).
These labels may be used in various assays as are also well known
in the art to achieve characterization.
(III) Antibodies
[0258] BTLA, HVEM and B7x proteins and fragments thereof, HVEM CRD1
domain peptides, BTLA Ig domain peptides, BTLA fusion proteins, B7x
fusion proteins, and HVEM fusion proteins may be used to generate
anti-BTLA and anti-B7x antibodies of the invention.
[0259] The terms "antibody" and "antibodies" as used herein include
both monoclonal and polyclonal antibodies as well as antibody
fragments, as are known in the art, including Fab, F(ab)2, single
chain antibodies (Fv for example), chimeric antibodies, humanized
antibodies, etc., either produced by the modification of whole
antibodies or those synthesized de novo using recombinant DNA
technologies, as described in more detail herein. Antibody
fragments include those portions of the antibody that bind to an
epitope on the BTLA or B7x polypeptides. Antibody fragments include
those portions of the antibody that bind to an HVEM CRD1 domain or
a BTLA Ig domain.
[0260] Preferably, when a B7x, BTLA or HVEM protein fragment is to
be used as an immunogen to generate antibodies, the fragment must
share at least one epitope or determinant with the full length
protein, particularly in an HVEM CRD1 domain or a BTLA Ig domain.
By epitope or determinant herein is meant a portion of a protein
which will generate and/or bind an antibody. Thus, in most
instances, antibodies made to a smaller or truncated B7x, BTLA or
HVEM protein will be able to bind to the corresponding full length
protein. In a preferred embodiment, the epitope is unique; that is,
antibodies generated to a unique epitope show little or no
cross-reactivity.
[0261] In one embodiment, the invention provides antagonistic BTLA
antibodies that are capable of reducing, including eliminating, one
or more biological functions of the BTLA protein expressed at the
surface of a cell. That is, the addition of anti-BTLA antibodies
(polyclonal, or preferably monoclonal) to BTLA proteins (or cells
comprising BTLA proteins) may reduce or eliminate at least one BTLA
protein activity. BTLA activity includes but is not limited to the
inhibition of lymphocyte activation; phosphorylation of tyrosine
residues in the Grb2 binding site, the ITIM, or the ITSM; binding
to SHP-1 and/or SHP-2; and activation of SHP-1 and/or SHP-2. The
reduction of BTLA activity is observed in the presence of BTLA
agonist (eg. HVEM on the surface of a second cell) which stimulates
BTLA activity in the absence of an antagonistic BTLA antibody. In a
preferred embodiment, such an antagonistic BTLA antibody interferes
with the binding of HVEM on the surface of one cell to BTLA on the
surface of a second cell. Generally, at least a 25% decrease in
activity is preferred, with at least about 50% being particularly
preferred and about a 95-100% decrease being especially preferred.
These antibodies are also sometimes referred to herein as
function-blocking antibodies or, more generally, as blocking
agents. In a particularly preferred embodiment, such an antibody
has the ability to modulate lymphocyte activity and, still more
preferably, to increase and/or up-regulate such activity by
inhibiting negative BTLA-mediated signaling. Further, such
antibodies have the ability to modulate immunoglobulin production
by B cells expressing BTLA, and more preferably, to increase
immunoglobulin production.
[0262] In an alternative embodiment, the invention provides
agonistic BTLA antibodies that increase or potentiate one or more
biological functions of the BTLA protein expressed at the surface
of a cell (a function-activating antibody), and/or mimics the
natural binding interaction of B7x of HVEM with BTLA (more
generally, a "mimicking agent"). That is, the addition of an
agonistic BTLA antibody (polyclonal, or preferably monoclonal) to a
cell expressing BTLA at its surface will increase or potentiate at
least one BTLA activity. BTLA activity includes but is not limited
to the inhibition of lymphocyte activation; phosphorylation of
tyrosine residues in the Grb2 binding site, the ITIM, or the ITSM;
binding to SHP-1 and/or SHP-2; and activation of SHP-1 and/or
SHP-2.
[0263] In a preferred embodiment, the agonistic BTLA antibodies are
function-activating antibodies. Such antibodies have the ability to
decrease B and T lymphocyte activation by increasing BTLA activity
in lymphocytes. Further, such antibodies have the ability to
modulate immunoglobulin production by B cells expressing BTLA, and
more particularly, to decrease immunoglobulin production. Further,
such an antibody may have the ability to modulate immunoglobulin
production by B cells expressing BTLA, and more preferably, to
decrease immunoglobulin production.
[0264] The anti-BTLA antibodies of the invention bind to BTLA
proteins. In a preferred embodiment, the BTLA antibody of the
invention specifically binds to the BTLA Ig domain of a BTLA
protein. By "specifically bind" herein is meant that the antibodies
bind to the protein with a binding constant in the range of at
least 10.sup.-4-10.sup.-6 M.sup.-1, with a preferred range being
10.sup.-7-10.sup.-9 M.sup.-1.
[0265] The present invention provides antibodies that specifically
bind to naturally occurring human BTLA and/or murine BTLA proteins.
In a preferred embodiment, the present invention provides a
monoclonal anti-BTLA antibody that specifically binds to murine
and/or human BTLA proteins and in particular to one or more
epitopes in the extracellular domains of such proteins. In an
especially preferred embodiment, the monoclonal antibody provided
is capable of inhibiting BTLA-mediated signaling, e.g., by
interfering with the natural interaction of HVEM and BTLA.
[0266] The BTLA proteins bound by BTLA antibodies may be human BTLA
proteins, murine BTLA proteins, or other, preferably mammalian,
BTLA proteins. In a preferred embodiment, the BTLA protein is a
human BTLA protein.
[0267] The murine BTLA gene is polymorphic, and variations in
sequence within the Ig domain that binds to murine HVEM are
described herein in the figures. Despite their sequence variation,
the murine BTLA Ig domains are each capable of binding to murine
HVEM, and a number of BTLA blocking antibodies are capable of
binding to multiple isoforms of murine BTLA.
[0268] The human BTLA gene is also polymorphic, as disclosed in
U.S. application Ser. No. 10/600,997, expressly incorporated herein
in its entirety by reference. As disclosed herein, human HVEM is
capable of binding to human BTLA. It is within the skill of the
artisan to determine if alternative alleles of human BTLA are
capable of binding to HVEM. As used herein, the term "BTLA"
includes any human isoform of BTLA that is capable of binding to
HVEM.
[0269] In a preferred embodiment, the present invention provides
monoclonal BTLA antibodies that specifically bind to murine and/or
human BTLA proteins.
[0270] In one embodiment, the invention provides antagonistic HVEM
antibodies that are capable of reducing, including eliminating, the
ability of HVEM protein when expressed at the surface of a cell to
increase BTLA activity in a second cell expressing BTLA at its
surface. BTLA activity includes but is not limited to the
inhibition of lymphocyte activation; phosphorylation of tyrosine
residues in the Grb2 binding site, the ITIM, or the ITSM; binding
to SHP-1 and/or SHP-2; and activation of SHP-1 and/or SHP-2. In a
preferred embodiment, such an antagonistic HVEM antibody interferes
with the binding of HVEM on the surface of one cell to BTLA on the
surface of a second cell.
[0271] Generally, at least a 25% decrease in activity is preferred,
with at least about 50% being particularly preferred and about a
95-100% decrease being especially preferred.
[0272] Such antibodies have the ability to increase B and T
lymphocyte activation by decreasing BTLA activity in lymphocytes.
Further, such antibodies have the ability to modulate
immunoglobulin production by B cells expressing BTLA, and more
particularly, to increase immunoglobulin production.
[0273] The HVEM antibodies of the invention specifically bind to
HVEM CRD1 domains. By "specifically bind" herein is meant that the
antibodies bind to the protein with a binding constant in the range
of at least 10.sup.-4-10.sup.-6 M.sup.-1, with a preferred range
being 10-7-10-9
[0274] The HVEM proteins bound by HVEM antibodies may be human HVEM
proteins, murine HVEM proteins, or other, preferably mammalian,
HVEM proteins.
[0275] HVEM protein sequences and encoding nucleic acid sequences
are well known in the art. For example, see Montgomery et al.,
Cell, 87: 427-436, 1996; Kwon et al., Journal of Biological
Chemistry, 272:14272-14276, 1997; Hsu et al., Journal of Biological
Chemistry 272:13471-13474, 1997.
[0276] Stemming from the discovery of the HVEM-BTLA interaction, in
one aspect, the present invention provides BTLA antibodies,
sometimes referred to herein as BTLA blocking antibodies. A BTLA
antibody of the invention is capable of specifically binding to a
BTLA protein and is capable of reducing the binding of the BTLA
protein to an HVEM protein. Especially preferred are BTLA
antibodies that specifically bind to a region of the BTLA Ig
domain, which region binds to the HVEM CRD1 domain. Such a BTLA
antibody is capable of binding to a fragment of the BTLA Ig domain,
which fragment is capable of binding to an HVEM CRD1 domain.
[0277] In one embodiment, a BTLA antibody is capable of binding to
a mouse BTLA Ig domain.
[0278] In one embodiment, a BTLA antibody is capable of binding to
a mouse BTLA Ig domain in a human BTLA tetramer.
[0279] In one embodiment, a BTLA antibody is capable of binding to
a human BTLA Ig domain.
[0280] In one embodiment, a BTLA antibody is capable of binding to
a human BTLA Ig domain in a human BTLA tetramer.
[0281] In one embodiment, a BTLA antibody is capable of binding
toward the DEBA face of the Ig fold of BTLA. The phrase "DEBA face"
refers to the regions of the BTLA molecule composed of the beta
strands labelled "D", "E", "B", and "A" strands. See, for example,
structure of BTLA ectodomain deposited at NCB! by C. A. Nelson, D.
H. Fremont, Midwest Center For Structural & Genomics (Mcsg), 26
Aug. 2004. See also Compaan et al., J Biol. Chem. 2005 Sep. 16,
Epub manuscript M507629200.
[0282] In one embodiment, a BTLA antibody is capable of binding an
epitope of BTLA that is capable of binding to an antibody selected
from the group consisting of `6A6`, `6F7`, `6G3`, `6H6`, `8F4`, and
`3F9.D12`.
[0283] In one embodiment, a BTLA antibody is capable of competing
with an antibody selected from the group consisting of `6A6`,
`6F7`, `6G3`, `6H6`, `8F4`, and `3F9.D12` for binding to BTLA.
[0284] In one embodiment, a BTLA antibody is capable of binding to
an epitope of BTLA that is homologous to an epitope capable of
binding an antibody selected from the group consisting of `6A6`,
`6F7`, `6G3`, `6H6`, `8F4`, and `3F9.D12`.
[0285] In one embodiment, a BTLA antibody is capable of binding to
an epitope comprising one or more residues selected from the group
consisting of R55, Q63, Q 102, and C85 of murine C57BL/6 BTLA (SEQ
ID NO: 63).
[0286] In one embodiment, a BTLA antibody is capable of binding to
an epitope comprising one or more residues selected from the group
consisting of the residues in a BTLA protein corresponding to the
residues V42, Q43, L44, R55, Q63, Q102, and C85 of murine C57BL/6
BTLA (SEQ ID NO: 63).
[0287] In one embodiment, a BTLA antibody is capable of binding to
an epitope comprising one or more residues selected from the group
consisting of the residues in human BTLA corresponding to the
residues V42, Q43, L44, R55, Q63, Q102, and C85 of murine C57BL/6
BTLA (SEQ ID NO: 63).
[0288] In one embodiment, a BTLA antibody is capable of binding to
an epitope comprising one or more residues selected from the group
consisting of V36, Q37, L38, L49, E57, C79, K93, and S96 in the
human BTLA sequence set forth at Genbank accession no. AAP44003.1
(SEQ ID NO: 64).
[0289] In one embodiment, a BTLA antibody is capable of binding to
an epitope comprising one or more residues in a human BTLA
corresponding to residues from the group consisting of V36, Q37,
L38, L49, E57, C79, K93, and S96 in the human BTLA sequence set
forth at Genbank accession no. AAP44003.1 (SEQ ID NO: 64).
[0290] In one embodiment, a BTLA antibody is capable of binding to
a polypeptide having at least about 80%, more preferably 85%, more
preferably 90%, more preferably 95% identity to the amino acid
sequence set forth by residues 37-47, 39-49, 41-49, 50-60, 58-68,
80-90, 97-107, 50-90, 55-85, 58-90, 63-85, 80-107, 85-102, 127-137,
55-102, 50-107, and 41-137 of murine BI/6 BTLA (SEQ ID NO: 63).
[0291] In one embodiment, a BTLA antibody is capable of binding to
a polypeptide selected from the group consisting of the amino acid
sequences set forth by residues 37-47, 39-49, 41-49, 50-60, 58-68,
80-90, 97-107, 50-90, 55-85, 58-90, 63-85, 80-107, 85-102, 127-137,
55-102, 50-107, and 41-137 of murine C57BL/6 BTLA (SEQ ID NO:
63).
[0292] In one embodiment, a BTLA antibody is capable of binding to
a polypeptide having at least about 80%, more preferably 85%, more
preferably 90%, more preferably 95% identity to the amino acid
sequence set forth by residues 31-41, 32-42, 35-43, 44-54, 52-62,
74-84, 88-98, 44-84, 49-79, 52-84, 57-79, 74-98, 79-93, 118-128,
49-93, 44-98, 35-98, and 35-128 of the human BTLA isoform found at
Genbank accession no. AAP44003.1 (SEQ ID NO: 64).
[0293] In one embodiment, a BTLA antibody is capable of binding to
a polypeptide selected from the group consisting of the amino acid
sequences set forth by residues 31-41, 32-42, 35-43, 44-54, 52-62,
74-84, 88-98, 44-84, 49-79, 52-84, 57-79, 74-98, 79-93, 118-128,
49-93, 44-98, 35-98, and 35-128 of the human BTLA isoform found at
Genbank accession no. AAP44003.1 (SEQ ID NO: 64).
[0294] In one embodiment, a BTLA antibody is selected from the
group consisting of `6A6`, `6F7`, `6G3`, `6H6`, `8F4`, and
`3F9.D12`.
[0295] In one embodiment, a BTLA antibody is capable of competing
with CMV UL144 for binding to BTLA.
[0296] In one embodiment, the invention provides BTLA antibodies
which are monoclonal antibodies.
[0297] In one embodiment, the invention provides BTLA antibodies
which are human antibodies.
[0298] In one aspect, the invention provides a hybridoma that
produces a BTLA antibody disclosed herein.
[0299] In one aspect, the invention provides BTLA antibodies that
are capable of modulating BTLA activity.
[0300] In one embodiment, the invention provides BTLA antibodies
that are antagonistic BTLA antibodies, which are capable of
reducing BTLA activity. Such antibodies are capable of reducing the
activation of BTLA by HVEM. Preferably, such antagonistic BTLA
antibodies are also capable of reducing the activation of BTLA by
another ligand which binds to the HVEM binding region of BTLA, such
as UL144. The UL144 open reading frame in human cytomegalovirus
(CMV) encodes a homologue of the herpesvirus entry mediator, HVEM,
a member of the tumor necrosis factor receptor superfamily (Lurain
et al., J. Virol. 1999 December; 73(12):10040-50).
[0301] In another embodiment, the invention provides BTLA
antibodies that are agonistic BTLA antibodies, which are capable of
increasing BTLA activity. Such antibodies are capable of increasing
BTLA activity in a cell having BTLA on its surface.
[0302] In one aspect, the invention provides HVEM antibodies,
sometimes referred to herein as HVEM blocking antibodies. An HVEM
antibody specifically binds to an HVEM protein and is capable of
reducing the binding of the HVEM protein to a BTLA protein.
Especially preferred are HVEM antibodies that specifically bind to
a region of the HVEM CRD1 domain that binds to the BTLA Ig domain.
Such an HVEM antibody is capable of binding to a fragment of the
HVEM CRD1 domain, which fragment is capable of binding to a BTLA Ig
domain. Preferred HVEM antibodies do not bind to the HVEM CRD2 or
HVEM CRD3 domains, though antibodies binding to the CRD2 and/or
CRD3 domains in addition to the CRD1 domain may be used in the
methods herein.
[0303] In one embodiment, the invention provides HVEM antibodies
which are monoclonal antibodies.
[0304] In one aspect, the invention provides a hybridoma that
produces a HVEM antibody disclosed herein.
[0305] In one embodiment, the invention provides HVEM antibodies
which are human antibodies.
[0306] In one aspect, the invention provides HVEM antibodies that
are capable of modulating BTLA activity.
[0307] In a preferred embodiment, the invention provides HVEM
antibodies that are antagonistic HVEM antibodies, which are capable
of reducing the ability of HVEM to activate BTLA on the surface of
a cell.
[0308] In another embodiment, the invention provides HVEM
antibodies that are agonistic HVEM antibodies, which are capable of
binding to HVEM and stimulating HVEM activity in a cell, thereby
mimicking BTLA. HVEM activity in this sense includes increased
NF-kB activity and increased AP-1 activity.
[0309] In one embodiment, the invention provides HVEM antibodies
that do not inhibit the binding of HVEM to LIGHT or LT.alpha..
[0310] In one embodiment, the invention provides HVEM antibodies
that additionally reduce the binding of HSV-1 glycoprotein D to
HVEM.
[0311] In another embodiment, the invention provides anti-B7x
antibodies. In preferred embodiments, the anti-B7x antibodies are
capable of reducing or eliminating one or more biological functions
of the B7x polypeptide described herein. That is, the addition of
anti-B7x antibodies (polyclonal, or preferably monoclonal) to B7x
proteins (or cells comprising B7x proteins) may reduce or eliminate
at least one B7x protein activity. Generally, at least a 25%
decrease in activity is preferred, with at least about 50% being
particularly preferred and about a 95-100% decrease being
especially preferred. These antibodies are sometimes referred to
herein as function-blocking antibodies or, more generally, blocking
agents. Preferably, such an antibody has the ability to modulate
lymphocyte activity, and more preferably, to increase and/or
up-regulate lymphocyte activity by interfering with the functional
interaction of BTLA and
[0312] B7x. Further, such an antibody may have the ability to
modulate immunoglobulin production by B cells expressing BTLA, and
more preferably, to increase immunoglobulin production.
[0313] In an alternative embodiment, the invention provides an
anti-B7x antibody that increases or potentiates the activity of B7x
(a function-activating antibody).
[0314] The anti-B7x antibodies of the invention bind to B7x
proteins. In a preferred embodiment, the antibodies specifically
bind to B7x proteins. By "specifically bind" herein is meant that
the antibodies bind to the protein with a binding constant in the
range of at least 10.sup.-4-10.sup.-6 M.sup.-1, with a preferred
range being 10.sup.-7-10.sup.-6 M.sup.-1.
[0315] The present invention provides antibodies that specifically
bind to naturally occurring human B7x and/or murine B7x proteins.
In a preferred embodiment, the present invention provides a
monoclonal anti-B7x antibody that specifically binds to murine
and/or human B7x protein. In an especially preferred embodiment,
the monoclonal antibody provided is capable of interfering with the
natural interaction of B7x and BTLA and inhibiting BTLA-mediated
signaling
[0316] The term "antibody", as used herein, includes immunoglobulin
molecules comprised of four polypeptide chains, two heavy (H)
chains and two light (L) chains inter-connected by disulfide bonds.
Each heavy chain is comprised of a heavy chain variable region
(abbreviated herein as HCVR or VH) and a heavy chain constant
region. The heavy chain constant region is comprised of three
domains, CH1, CH2 and CH3. Each light chain is comprised of a light
chain variable region (abbreviated herein as LCVR or VL) and a
light chain constant region. The light chain constant region is
comprised of one domain, CL. The VH and VL regions can be further
subdivided into regions of hypervariability, termed complementarity
determining regions (CDR), interspersed with regions that are more
conserved, termed framework regions (FR). Each VH and VL is
composed of three CDRs and four FRs, arranged from amino-terminus
to carboxy-terminus in the following order: FR1, CDR1, FR2, CDR2,
FR3, CDR3, FR4. The phrase "complementary determining region" (CDR)
includes the region of an antibody molecule which comprises the
antigen binding site.
[0317] The antibody may be an IgG such as IgG1, IgG2, IgG3 or IgG4;
or IgM, IgA, IgE or IgD isotype. The constant domain of the
antibody heavy chain may be selected depending upon the effector
function desired. The light chain constant domain may be a kappa or
lambda constant domain.
[0318] The term "antibody" as used herein also encompasses antibody
fragments, and in particular, fragments that retain the ability to
specifically bind to an antigen (e.g., the extracellular domain of
B7x, the HVEM CRD1 domais or the BTLA Ig domain). It has been shown
that the antigen-binding function of an antibody can be performed
by fragments of a full-length antibody. Examples of such binding
fragments include (i) a Fab fragment, a monovalent fragment
consisting of the VL, VH, CL and CH1 domains; (ii) a F(ab').sub.2
fragment, a bivalent fragment comprising two Fab fragments linked
by a disulfide bridge at the hinge region; (iii) a Fd fragment
consisting of the VH and CHI domains; (iv) a Fv fragment consisting
of the VL and VH domains of a single arm of an antibody, (v) a dAb
fragment (Ward et al., (1989) Nature 341:544-546), which consists
of a VH domain; and (vi) an isolated complementarity determining
region (CDR). Furthermore, although the two domains of the Fv
fragment, VL and VH, are coded for by separate genes, they can be
joined, using recombinant methods, by a synthetic linker that
enables them to be made as a single protein chain in which the VL
and VH regions pair to form monovalent molecules (known as single
chain Fv (scFv); see e.g., Bird et al. (1988) Science 242:423-426;
and Huston et al. (1988) Proc. Natl. Acad. Sci. USA 85:5879-5883).
Such single chain antibodies are also intended to be encompassed
within the term "antibody." Other forms of single chain antibodies,
such as diabodies are also encompassed. Diabodies are bivalent,
bispecific antibodies in which VH and VL domains are expressed on a
single polypeptide chain, but using a linker that is too short to
allow for pairing between the two domains on the same chain,
thereby forcing the domains to pair with complementary domains of
another chain and creating two antigen binding sites (see e.g.,
Holliger, P., et al. (1993) Proc. Natl. Acad. Sci. USA
90:6444-6448; Poljak, R. J., et al. (1994) Structure
2:1121-1123).
[0319] Still further, an antibody or fragment thereof may be part
of a larger immunoadhesion molecule, formed by covalent or
noncovalent association of the antibody or antibody portion with
one or more other proteins or peptides. Examples of such
immunoadhesion molecules include use of the streptavidin core
region to make a tetrameric scFv molecule (Kipriyanov, S. M., et
al. (1995) Human Antibodies and Hybridomas 6:93-101) and use of a
cysteine residue, a marker peptide and a C-terminal polyhistidine
tag to make bivalent and biotinylated scFv molecules (Kipriyanov,
S. M., et al. (1994) Mol. Immunol. 31:1047-1058). Antibody
portions, such as Fab and F(ab').sub.2 fragments, can be prepared
from whole antibodies using conventional techniques, such as papain
or pepsin digestion, respectively, of whole antibodies. Moreover,
antibodies, antibody fragments and immunoadhesion molecules can be
obtained using standard recombinant DNA techniques, as described
herein.
[0320] Antibodies may be polyclonal or monoclonal; xenogeneic,
allogeneic, or syngeneic; or modified forms thereof, e.g.
humanized, chimeric, etc. Preferably, antibodies of the invention
bind specifically or substantially specifically to HVEM, B7x and/or
BTLA. The terms "monoclonal antibodies" and "monoclonal antibody
composition", as used herein, refer to a population of antibody
molecules that contain only one species of an antigen binding site
capable of immunoreacting with a particular epitope of an antigen,
whereas the term "polyclonal antibodies" and "polyclonal antibody
composition" refer to a population of antibody molecules that
contain multiple species of antigen binding sites capable of
interacting with a particular antigen. A monoclonal antibody
composition typically displays a single binding affinity for a
particular antigen with which it immunoreacts.
[0321] The antibodies described herein may be humanized antibodies,
e.g., antibodies made by a non-human cell having variable and
constant regions which have been altered to more closely resemble
antibodies that would be made by a human cell. For example, by
altering the non-human antibody amino acid sequence to incorporate
amino acids found in human germline immunoglobulin sequences. The
humanized antibodies of the invention may include amino acid
residues not encoded by human germline immunoglobulin sequences
(e.g., mutations introduced by random or site-specific mutagenesis
in vitro or by somatic mutation in vivo), for example in the CDRs.
Such humanized antibodies may also include antibodies in which CDR
sequences derived from the germline of another mammalian species,
such as a mouse, have been grafted onto human framework
sequences.
[0322] As used herein, the term "extracellular domain of B7x"
includes a portion of the B7x peptide which, in the cell-associated
form, is extracellular. A B7x extracellular domain includes the
portion of a B7x polypeptide involved in its interaction with BTLA.
Similarly, the term "extracellular domain of BTLA" includes a
portion of the BTLA peptide which, in the cell-associated form, is
extracellular. A BTLA extracellular domain includes the portion of
a BTLA polypeptide involved in its interaction with B7x.
[0323] Preferably, the anti-BTLA antibodies of the invention bind
to naturally occurring forms of BTLA, but are substantially
unreactive, e.g., have background binding to unrelated molecules.
More preferably, such antibodies may also be specific for BTLA and
substantially unreactive with other co-stimulatory T cell
receptors, e.g. CTLA-4, CD28 and PD-1. Similarly, the anti-B7x
antibodies of the invention preferably bind to naturally occurring
forms of B7x, but are substantially unreactive, e.g., have
background binding to unrelated, non-B7 molecules. In a
particularly preferred embodiment such antibodies may also be
specific for B7x and substantially unreactive with related B7
molecules, e.g. B7.1 or B7.2.
[0324] In addition, antibodies specific for naturally occurring
HVEM, B7x or BTLA peptides may or may not bind to mutant forms of
such peptides. In one embodiment, mutations in the amino acid
sequence of a naturally occurring HVEM, B7x or BTLA peptide result
in modulation of the binding (e.g., either increased or decreased
binding) of the antibody to the HVEM, B7x or BTLA peptide,
respectively. Antibodies to HVEM, B7x and BTLA peptides can be
readily screened for their ability to meet this criteria. Assays to
determine affinity and specificity of binding are known in the art,
including competitive and non-competitive assays. Assays of
interest include ELISA, RIA, flow cytometry, etc. Binding assays
may use purified or semi-purified HVEM, B7x or BTLA protein, or
alternatively may use cells that express HVEM, B7x or BTLA, e.g.
cells transfected with an expression construct for HVEM, B7x or
BTLA.
[0325] As is well known in the art, HVEM, B7x and BTLA polypeptides
from a variety of species, whether in soluble form or membrane
bound, can be used as immunogens to induce the formation of
anti-HVEM, anti-B7x and anti-BTLA antibodies, respectively. A
variety of techniques for the preparation of such antibodies,
whether polyclonal, monoclonal or humanized, are well know to the
skilled artisan and do not require recitation herein. A concise
summary of such techniques with reference to the preparation of
antibodies to known B7 antigens is provided in U.S. Patent
Publication No. US 2002/0071839, the entire disclosure of which is
expressly incorporated herein by reference.
Antibody Structure
[0326] The basic antibody structural unit is known to comprise a
tetramer. Each tetramer is composed of two identical pairs of
polypeptide chains, each pair having one "light" (about 25 kDa) and
one "heavy" chain (about 50-70 kDa). The amino-terminal portion of
each chain includes a variable region of about 100 to 110 or more
amino acids primarily responsible for antigen recognition. The
carboxy-terminal portion of each chain defines a constant region
primarily responsible for effector function. Human light chains are
classified as kappa and lambda light chains. Heavy chains are
classified as mu, delta, gamma, alpha, or epsilon, and define the
antibody's isotype as IgM, IgD, IgG, IgA, and IgE, respectively.
Within light and heavy chains, the variable and constant regions
are joined by a "J" region of about 12 or more amino acids, with
the heavy chain also including a "D" region of about 10 more amino
acids. See generally, Fundamental Immunology Ch. 7 (Paul, W., ed.,
2nd ed. Raven Press, N.Y. (1989)) (incorporated by reference in its
entirety for all purposes). The variable regions of each
light/heavy chain pair form the antibody binding site.
[0327] Thus, an intact IgG antibody has two binding sites. Except
in bifunctional or bispecific antibodies, the two binding sites are
the same.
[0328] The chains all exhibit the same general structure of
relatively conserved framework regions (FR) joined by three hyper
variable regions, also called complementarity determining regions
or CDRs. The CDRs from the two chains of each pair are aligned by
the framework regions, enabling binding to a specific epitope. From
N-terminal to C-terminal, both light and heavy chains comprise the
domains FR1, CDR1, FR2, CDR2, FR3, CDR3 and FR4. The assignment of
amino acids to each domain is in accordance with the definitions of
Kabat Sequences of Proteins of Immunological Interest (National
Institutes of Health, Bethesda, Md. (1987 and 1991)), or Chothia
& Lesk J. Mol. Biol. 196:901-917 (1987); Chothia et al. Nature
342:878-883 (1989).
[0329] A bispecific or bifunctional antibody is an artificial
hybrid antibody having two different heavy/light chain pairs and
two different binding sites. Bispecific antibodies can be produced
by a variety of methods including fusion of hybridomas or linking
of Fab' fragments. See, e.g., Songsivilai & Lachmann Clin. Exp.
Immunol. 79: 315-321 (1990), Kostelny et al. J. Immunol.
148:1547-1553 (1992). In addition, bispecific antibodies may be
formed as "diabodies" (Holliger et al. "`Diabodies`: small bivalent
and bispecific antibody fragments" PNAS USA 90:6444-6448 (1993)) or
"Janusins" (Traunecker et al. "Bispecific single chain molecules
(Janusins) target cytotoxic lymphocytes on HIV infected cells" EMBO
J. 10:3655-3659 (1991) and Traunecker et al. "Janusin: new
molecular design for bispecific reagents" Int J Cancer Suppl
7:51-52 (1992)). Production of bispecific antibodies can be a
relatively labor intensive process compared with production of
conventional antibodies and yields and degree of purity are
generally lower for bispecific antibodies. Bispecific antibodies do
not exist in the form of fragments having a single binding site
(e.g., Fab, Fab', and Fv).
Human Antibodies and Humanization of Antibodies
[0330] Human antibodies avoid certain of the problems associated
with antibodies that possess murine or rat variable and/or constant
regions. The presence of such murine or rat derived proteins can
lead to the rapid clearance of the antibodies or can lead to the
generation of an immune response against the antibody by a patient.
In order to avoid the utilization of murine or rat derived
antibodies, it has been postulated that one can develop humanized
antibodies or generate fully human antibodies through the
introduction of human antibody function into a rodent so that the
rodent would produce antibodies having fully human sequences.
Human Antibodies
[0331] Introduction of human immunoglobulin (Ig) loci into mice in
which the endogenous Ig genes have been inactivated provides an
ideal source for production of fully human monoclonal antibodies
(Mabs). Fully human antibodies are expected to minimize the
immunogenic and allergic responses intrinsic to mouse or
mouse-derivatized Mabs and thus to increase the efficacy and safety
of the administered antibodies. The use of fully human antibodies
can be expected to provide a substantial advantage in the treatment
of chronic and recurring human diseases, such as cancer, which may
require repeated antibody administrations.
[0332] Mouse strains have been engineered with large fragments of
the human Ig loci and to produce human antibodies in the absence of
mouse antibodies.
[0333] See Green et al. Nature Genetics 7:13-21 (1994). The
XenoMouse.TM. strains were engineered with yeast artificial
chromosomes (YACs) containing 245 kb and 190 kb-sized germline
configuration fragments of the human heavy chain locus and kappa
light chain locus, respectively, which contained core variable and
constant region sequences. Further reported work involved the
introduction of greater than approximately 80% of the human
antibody repertoire through introduction of megabase sized,
germline configuration YAC fragments of the human heavy chain loci
and kappa light chain loci, respectively, to produce XenoMouse.TM.
mice. See Mendez et al. Nature Genetics 15:146-156 (1997), Green
and Jakobovits J. Exp. Med. 188:483-495 (1998), the disclosures of
which are hereby incorporated by reference.
[0334] Such approaches are further discussed and delineated in
European Patent No., EP 0 463 151 B1, grant published Jun. 12,
1996, International Patent Application No., WO 94/02602, published
Feb. 3, 1994, International Patent Application No., WO 96/34096,
published Oct. 31, 1996, and WO 98/24893, published Jun. 11, 1998.
The disclosures of each of the above-cited patents, applications,
and references are hereby incorporated by reference in their
entirety.
[0335] In an alternative approach, others have utilized a
"minilocus" approach. In the minilocus approach, an exogenous Ig
locus is mimicked through the inclusion of pieces (individual
genes) from the Ig locus. Thus, one or more VH genes, one or more
DH genes, one or more JH genes, a p constant region, and a second
constant region (preferably a gamma constant region) are formed
into a construct for insertion into an animal. This approach is
described in U.S. Pat. No. 5,545,807 to Surani et al. and U.S. Pat.
Nos. 5,545,806, 5,625,825, 5,625,126, 5,633,425, 5,661,016,
5,770,429, 5,789,650, and 5,814,318 each to Lonberg and Kay, U.S.
Pat. No. 5,591,669 to Krimpenfort and Berns, U.S. Pat. Nos.
5,612,205, 5,721,367, 5,789,215 to Berns et al., and U.S. Pat. No.
5,643,763 to Choi and Dunn. See also European Patent No. 0 546 073
B1, International Patent Application Nos. WO 92/03918, WO 92/22645,
WO 92/22647, WO 92/22670, WO 93/12227, WO 94/00569, WO 94/25585, WO
96/14436, WO 97/13852, and WO 98/24884, the disclosures of which
are hereby incorporated by reference in their entirety. See further
Taylor et al., Nucleic Acids Research 20:6287-6295 (1992); Chen et
al. International Immunology 5:647-656 (1993); Tuaillon et al.,
Proc. Natl. Acad. Sci. USA 90:3720-3724 (1993); Choi et al., Nature
Genetics 4:117-123 (1993); Lonberg et al., Nature 368:856-859
(1994); Taylor et al., International Immunology 6:579-59.1 (1994);
Tuaillon et al., J. Immunol. 154:6453-6465 (1995); Fishwild et al.,
Nature Biotech. 14:845-851 (1996); the disclosures of which are
hereby incorporated by reference in their entirety.
(IV) Bioactive Agents
[0336] It will be appreciated by those skilled in the art that it
is within their skill to generate bioactive agents and screen for
their activity by following standard techniques. In a preferred
embodiment, the B7x, HVEM, and/or BTLA proteins, nucleic acids,
variants, modified proteins, cells and/or transgenics containing
the said nucleic acids or proteins are used in screening assays.
Identification of the B7x, HVEM, and/or BTLA proteins provided
herein permits the design of drug screening assays for compounds
that bind B7x, HVEM, and/or BTLA proteins, interfere with B7x,
HVEM, and/or BTLA protein binding, or modulate B7x, HVEM, and/or
BTLA activity.
[0337] The assays described herein preferably utilize human B7x,
human BTLA proteins, and human HVEM, although other mammalian
proteins may also be used, including rodents (mice, rats, hamsters,
guinea pigs, etc.), farm animals (cows, sheep, pigs, horses, etc.)
and primates. These latter embodiments may be preferred in the
development of animal models of human disease.
[0338] In some embodiments, the methods comprise combining a B7x
protein and a candidate bioactive agent, and determining the
binding of the candidate agent to the B7x protein. In other
embodiments, further discussed below, binding interference or
bioactivity is determined.
[0339] In preferred embodiments, the methods comprise combining a
BTLA protein and a candidate bioactive agent, and determining the
binding of the candidate agent to the BTLA protein. In other
embodiments, further discussed below, binding interference or
bioactivity is determined.
[0340] In other preferred embodiments, the methods comprise
combining an Ig domain of a BTLA protein, or an HVEM binding
portion thereof, with a candidate bioactive agent, and determining
the binding of the candidate agent to the BTLA domain. In another
preferred embodiment, the methods involve combining an HVEM CRD1
domain, or a BTLA binding portion thereof, with a candidate agent,
and determining the binding of the candidate agent to the HVEM
domain.
[0341] The term "candidate bioactive agent" or "exogenous compound"
as used herein describes any molecule, e.g., protein, small organic
molecule, carbohydrates (including polysaccharides),
polynucleotide, lipids, etc. Generally a plurality of assay
mixtures are run in parallel with different agent concentrations to
obtain a differential response to the various concentrations.
Typically, one of these concentrations serves as a negative
control, i.e., at zero concentration or below the level of
detection. In addition, positive controls, i.e. the use of agents
known to bind B7x protein, e.g. BTLA, may be used, and vice-versa.
In addition, positive controls, i.e. the use of agents known to
bind BTLA or HVEM may be used.
[0342] Candidate agents encompass numerous chemical classes, though
typically they are organic molecules, preferably small organic
compounds having a molecular weight of more than 100 and less than
about 2,500 daltons, more preferably between 100 and 2000, more
preferably between about 100 and about 1250, more preferably
between about 100 and about 1000, more preferably between about 100
and about 750, more preferably between about 200 and about 500
daltons. Candidate agents comprise functional groups necessary for
structural interaction with proteins, particularly hydrogen
bonding, and typically include at least an amine, carbonyl,
hydroxyl or carboxyl group, preferably at least two of the
functional chemical groups. The candidate agents often comprise
cyclical carbon or heterocyclic structures and/or aromatic or
polyaromatic structures substituted with one or more of the above
functional groups. Candidate agents are also found among
biomolecules including peptides, saccharides, fatty acids,
steroids, purines, pyrimidines, derivatives, structural analogs or
combinations thereof. Particularly preferred are peptides, e.g.,
peptidomimetics. Peptidomimetics can be made as described, e.g., in
WO 98/56401
[0343] Candidate agents are obtained from a wide variety of sources
including libraries of synthetic or natural compounds. For example,
numerous means are available for random and directed synthesis of a
wide variety of organic compounds and biomolecules, including
expression of randomized oligonucleotides. Alternatively, libraries
of natural compounds in the form of bacterial, fungal, plant and
animal extracts are available or readily produced. Additionally,
natural or synthetically produced libraries and compounds are
readily modified through conventional chemical, physical and
biochemical means. Known pharmacological agents may be subjected to
directed or random chemical modifications, such as acylation,
alkylation, esterification, amidification to produce structural
analogs.
[0344] In a preferred embodiment, the candidate bioactive agents
are organic chemical moieties or small molecule chemical
compositions, a wide variety of which are available in the
literature.
[0345] In one aspect, the invention provides BTLA-HVEM antagonists.
A BTLA-HVEM antagonist may be any of a wide variety of bioactive
agents capable of reducing the activation of BTLA by HVEM. In a
preferred embodiment, a BTLA-HVEM antagonist is capable of reducing
the binding of an HVEM CRD1 domain to a BTLA Ig domain. While many
BTLA-HVEM antagonists are capable of binding to BTLA, such a
BTLA-HVEM antagonist does not increase BTLA activity in a cell
expressing BTLA on its surface.
[0346] Preferred BTLA-HVEM antagonists are capable of reducing BTLA
activity in a cell having BTLA on its surface. In a preferred
embodiment, the cell is a lymphocyte, a T cell, a CD4+ T cell, a
TH1 cell, a CD8f T cell, a B cell, a plasma cell, a macrophage, or
an NK cell.
[0347] Suitable bioactive agents include BTLA antibodies and HVEM
antibodies (e.g., monoclonal, polyclonal, single chain, and/or
bispecific antibodies as well as Fab and F(ab).sub.2 fragments,
variants and derivatives thereof). Suitable bioactive agents also
include fragments and truncated forms of BTLA and HVEM proteins,
fusion proteins, and the like, for example, soluble proteins and
polypeptides comprising or consisting essentially of a BTLA Ig
domain fragment capable of binding an HVEM CRD1 domain; soluble
proteins and polypeptides comprising or consisting essentially of
an HVEM CRD1 domain or fragment thereof capable of binding a BTLA
Ig domain; a BTLA Ig domain peptide, a CRD1 domain peptide.
Suitable bioactive agents also include small molecule chemical
compositions.
[0348] In one embodiment, the invention provides a BTLA-HVEM
antagonist capable of reducing the binding of a BTLA protein to an
HVEM protein, wherein the antagonist does not comprise an HVEM CRD2
domain, an HVEM CRD3 domain, or both, and wherein the antagonist
does not bind to an HVEM CRD2 domain or an HVEM CRD3 domain, with
the proviso that the antagonist is not an HSV-1 glycoprotein D, a
phage-derived peptide BP-2, or a soluble protein comprising a
complete BTLA Ig domain capable of binding said HVEM protein.
[0349] In the methods herein, glycoprotein D and phage-derived
peptide BP-2, as well as HVEM-binding fragments thereof, and fusion
proteins comprising the same, may be used as BTLA-HVEM
antagonists.
[0350] Preferred BTLA-HVEM antagonists are capable of binding to a
BTLA Ig domain and are capable of reducing the binding of the BTLA
Ig domain to an HVEM CRD1 domain. Especially preferred are
BTLA-HVEM antagonists capable of binding to a region of the BTLA Ig
domain that binds to the HVEM CRD1 domain. Such a BTLA-HVEM
antagonist is capable of binding to a fragment of the BTLA Ig
domain, which fragment is capable of binding to an HVEM CRD1
domain.
[0351] In one embodiment, a BTLA-HVEM antagonist binds an epitope
of BTLA that is capable of binding to an antibody selected from the
group consisting of `6A6`, `6F7`, `6G3`, `6H6`, `8F4`, and
`3F9.D12`.
[0352] In one embodiment, a BTLA-HVEM antagonist is capable of
competing with an antibody selected from the group consisting of
`6A6`, `6F7`, `6G3`, `6H6`, `8F4`, and `3F9.D12` for binding to
BTLA.
[0353] In one embodiment, a BTLA-HVEM antagonist binds to an
epitope of BTLA that is homologous to an epitope capable of binding
an antibody selected from the group consisting of `6A6`, `6F7`,
`6G3`, `6H6`, `8F4`, and `3F9.D12`.
[0354] In one embodiment, a BTLA-HVEM antagonist is capable of
binding to an epitope comprising one or more residues selected from
the group consisting of V42, Q43, L44, R55, Q63, Q102, and C85 of
murine C57BL/6 BTLA (SEQ ID NO: 63).
[0355] In one embodiment, a BTLA-HVEM antagonist is capable of
binding to an epitope comprising one or more residues selected from
the group consisting of the residues in a BTLA protein
corresponding to the residues V42, Q43, L44, R55, Q63, Q102, and
C85 of murine C57BL/6 BTLA (SEQ ID NO: 63).
[0356] In one embodiment, a BTLA-HVEM antagonist is capable of
binding to an epitope comprising one or more residues selected from
the group consisting of the residues in human BTLA corresponding to
the residues V42, Q43, L44, R55, Q63, Q102, and C85 of murine
C57BL/6 BTLA (SEQ ID NO: 63).
[0357] In one embodiment, a BTLA-HVEM antagonist is capable of
binding to an epitope comprising one or more residues selected from
the group consisting of V36, Q37, L38, L49, E57, C79, K93, and S96
in the human BTLA sequence set forth at Genbank accession no.
AAP44003.1 (SEQ ID NO: 64).
[0358] In one embodiment, a BTLA-HVEM antagonist is capable of
binding to an epitope comprising one or more residues of human BTLA
corresponding to residues from the group consisting of V36, Q37,
L38, L49, E57, C79, K93, and S96 in the human BTLA sequence set
forth at Genbank accession no. AAP44003.1 (SEQ ID NO: 64).
[0359] In one embodiment, a BTLA-HVEM antagonist is capable of
binding to a polypeptide having at least about 80%, more preferably
85%, more preferably 90%, more preferably 95% identity to the amino
acid sequence set forth by residues 37-47, 39-49, 41-49, 50-60,
58-68, 80 90, 97-107, 50-90, 55-85, 58-90, 63-85, 80-107, 85-102,
127-137, 55-102, 50-107, and 41-137 of murine C57BL/6 BTLA (SEQ ID
NO: 63).
[0360] In one embodiment, a BTLA-HVEM antagonist is capable of
binding to a polypeptide selected from the group consisting of the
amino acid sequences set forth by residues 37-47, 39 49, 41-49,
50-60, 58-68, 80-90, 97-107, 50-90, 55-85, 58-90, 63-85, 80-107,
85-102, 127-137, 55-102, 50-107, and 41-137 of murine C57BL/6 BTLA
(SEQ ID NO: 63).
[0361] In one embodiment, a BTLA-HVEM antagonist is capable of
binding to a polypeptide having at least about 80%, more preferably
85%, more preferably 90%, more preferably 95% identity to the amino
acid sequence set forth by residues 31-41, 32-42, 35-43, 44-54,
52-62, 74 84, 88-98, 44-84, 49-79, 52-84, 57-79, 74-98, 79-93,
118-128, 49-93, 44-98, 35-98, and 35-128 of the human BTLA isoform
found at Genbank accession no. AAP44003.1 (SEQ ID NO: 64).
[0362] In one embodiment, a BTLA-HVEM antagonist is capable of
binding to a polypeptide selected from the group consisting of the
amino acid sequences set forth by residues 31-41, 32 42, 35-43,
44-54, 52-62, 74-84, 88-98, 44-84, 49-79, 52-84, 57-79, 74-98,
79-93, 118-128, 49-93, 44-98, 35-98, and 35-128 of the human BTLA
isoform found at Genbank accession no. AAP44003.1 (SEQ ID NO:
64).
[0363] In one embodiment, a BTLA-HVEM antagonist is capable of
competing with CMV UL144 for binding to BTLA.
[0364] In one embodiment, a BTLA-HVEM antagonist is capable of
competing with HSV-1 glycoprotein D for binding to HVEM.
[0365] In one embodiment, a BTLA-HVEM antagonist is a BTLA
antibody.
[0366] In one embodiment, a BTLA-HVEM antagonist is an HVEM
antibody.
[0367] In one aspect, the invention provides BTLA-HVEM antagonists
that comprise a BTLA Ig domain fragment capable of binding an HVEM
CRD1 domain. In another aspect, the invention provides BTLA-HVEM
antagonists that consist essentially of a BTLA Ig domain fragment
capable of binding an HVEM CRD1 domain.
[0368] Accordingly, in a preferred embodiment, the invention
provides BTLA-HVEM antagonists that are BTLA fusion proteins which
are capable of binding to an HVEM CRD1 domain and reducing the
binding of the HVEM CRD1 domain to a BTLA Ig domain. Preferred BTLA
fusion proteins do not bind to the CRD2 or CRD3 domains of HVEM.
Preferred BTLA fusion proteins can compete with an HVEM antibody
disclosed herein for binding to an HVEM CRD1 domain. Preferred BTLA
fusion proteins do not comprise an entire BTLA Ig domain.
[0369] In another preferred embodiment, the invention provides
BTLA-HVEM antagonists that are BTLA protein fragments which are
capable of binding to the CRD1 domain of HVEM and reducing the
binding of the HVEM CRD1 domain to a BTLA Ig domain. Preferred BTLA
protein fragments do not bind to the CRD2 or CRD3 domains of HVEM.
In a preferred embodiment, a BTLA protein fragment consists
essentially of a BTLA Ig domain fragment that is capable of binding
to an HVEM CRD1 domain. Preferred BTLA protein fragments can
compete with an HVEM antibody disclosed herein for binding to an
HVEM CRD1 domain.
[0370] In one aspect, the invention provides BTLA-HVEM antagonists
that comprise an HVEM CRD1 domain or fragment thereof capable of
binding to a BTLA Ig domain. In another aspect, the invention
provides BTLA-HVEM antagonists that consist essentially of an HVEM
CRD1 domain or fragment thereof capable of binding to a BTLA Ig
domain.
[0371] Accordingly, in a preferred embodiment, the invention
provides BTLA-HVEM antagonists that are HVEM fusion proteins which
are capable of binding to a BTLA Ig domain and reducing the binding
of the BTLA Ig domain to an HVEM CRD1 domain. Such HVEM fusion
proteins lack an HVEM CRD2 and/or CRD3 domain. Preferred HVEM
fusion proteins can compete with a BTLA antibody disclosed herein
for binding to a BTLA Ig domain.
[0372] In another preferred embodiment, the invention provides
BTLA-HVEM antagonists that are HVEM protein fragments which are
capable of binding to a BTLA Ig domain and reducing the binding of
the BTLA Ig domain to an HVEM CRD1 domain. Such HVEM protein
fragments lack an HVEM CRD2 and/or CRD3 domain. In a preferred
embodiment, an HVEM protein fragment consists essentially of an
HVEM CRD1 domain or fragment thereof which is capable of binding to
a BTLA Ig domain. Preferred HVEM protein fragments can compete with
a BTLA antibody disclosed herein for binding to a BTLA Ig
domain.
[0373] In one embodiment, the invention provides fusion proteins
that comprise an Fc region of an immunoglobulin.
[0374] In one embodiment, for use in the methods herein, HSV-1
glycoprotein D may be used as a BTLA-HVEM antagonist.
[0375] In one embodiment, a BTLA-HVEM antagonist is capable of
reducing tyrosine phosphorylation on the intracellular domain of
BTLA protein in a cell having BTLA protein on its surface.
[0376] In one embodiment, a BTLA-HVEM antagonist is capable of
reducing association of BTLA protein with SHP-2, PI3K, or Grb2 in a
cell having BTLA protein on its surface.
[0377] In one embodiment, a BTLA-HVEM antagonist is capable of
increasing proliferation of a cell having BTLA protein on its
surface.
[0378] In one embodiment, a BTLA-HVEM antagonist is capable of
increasing IL-2 production by a cell having BTLA protein on its
surface.
[0379] In one embodiment, a BTLA-HVEM antagonist is capable of
increasing or prolonging antibody production by a cell having said
BTLA protein on its surface.
[0380] In one embodiment, a BTLA-HVEM antagonist is capable of
increasing or prolonging the cytotoxicity of a cell having said
BTLA protein on its surface.
[0381] In one aspect, the invention provides BTLA-HVEM agonists. A
BTLA-HVEM agonist may be any of a wide variety of bioactive agents
capable of activating BTLA and thereby mimicking the activity of
HVEM.
[0382] Preferred BTLA-HVEM agonists are capable of increasing BTLA
activity in a cell having BTLA on its surface. In a preferred
embodiment, the cell is a lymphocyte, a T cell, a CD4+ T cell, a
TH1 cell, a CD8+ T cell, a B cell, a plasma cell, a macrophage, or
an NK cell.
[0383] Suitable bioactive agents include BTLA antibodies (e.g.,
monoclonal, polyclonal, single chain, and/or bispecific antibodies
as well as Fab and F(ab)2 fragments, variants and derivatives
thereof). Suitable bioactive agents also include fragments and
truncated forms of HVEM proteins, fusion proteins, and the like,
such as soluble proteins and polypeptides comprising or consisting
essentially of an HVEM CRD1 domain or fragment thereof capable of
binding to a BTLA Ig domain and increasing BTLA activity, and
lacking a CRD2 and/or CRD3 domain. Suitable bioactive agents also
include small molecule chemical compositions.
[0384] In one embodiment, the invention provides a BTLA-HVEM
agonist capable of binding to BTLA protein and increasing BTLA
activity, wherein the agonist does not comprise an HVEM CRD2
domain, an HVEM CRD3 domain, or both, with the proviso that the
agonist is not a human CMV UL144 protein.
[0385] In one embodiment, for use in the methods herein, CMV UL144,
BTLA-binding fragments thereof, and fusion proteins comprising the
same, may be used as a BTLA-HVEM agonist. Further regarding UL144,
see Cheung et al., PNAS 102:13218-13223, 2005.
[0386] Preferred BTLA-HVEM agonists bind to a BTLA Ig domain and
are capable of reducing the binding of the BTLA Ig domain to an
HVEM CRD1 domain, and mimicking the stimulation of BTLA by HVEM.
Especially preferred are BTLA-HVEM agonists are capable of binding
to a region of the BTLA Ig domain that binds to the HVEM CRD1
domain.
[0387] In one embodiment, a BTLA-HVEM agonist binds an epitope of
BTLA that is capable of binding to an antibody selected from the
group consisting of `6A6`, `6F7`, `6G3`, `6H6`, `8F4`, and
`3F9.D12`.
[0388] In one embodiment, a BTLA-HVEM agonist is capable of
competing with an antibody selected from the group consisting of
`6A6`, `6F7`, `6G3`, `6H6`, `8F4`, and `3F9.D12` for binding to
BTLA.
[0389] In one embodiment, a BTLA-HVEM agonist binds to an epitope
of BTLA that is homologous to an epitope capable of binding an
antibody selected from the group consisting of `6A6`, `6F7`, `6G3`,
`6H6`, `8F4`, and `3F9.D12`.
[0390] In one embodiment, a BTLA-HVEM agonist is capable of binding
to an epitope comprising one or more residues selected from the
group consisting of V42, Q43, L44, R55, Q63, Q102, and C85 of
murine C57BL/6 BTLA (SEQ ID NO: 63).
[0391] In one embodiment, a BTLA-HVEM agonist is capable of binding
to an epitope comprising one or more residues selected from the
group consisting of the residues in a BTLA protein corresponding to
the residues V42, Q43, L44, R55, Q63, Q102, and C85 of murine
C57BL/6 BTLA (SEQ ID NO: 63).
[0392] In one embodiment, a BTLA-HVEM agonist is capable of binding
to an epitope comprising one or more residues selected from the
group consisting of the residues in human BTLA corresponding to the
residues V42, Q43, L44, R55, Q63, Q102, and C85 of murine C57BL/6
BTLA (SEQ ID NO: 63).
[0393] In one embodiment, a BTLA-HVEM agonist is capable of binding
to an epitope comprising one or more residues selected from the
group consisting of V36, Q37, L38, L49, E57, C79, K93, and S96 in
the human BTLA sequence set forth at Genbank accession no.
AAP44003.1 (SEQ ID NO: 64).
[0394] In one embodiment, a BTLA-HVEM agonist is capable of binding
to an epitope comprising one or more residues in human BTLA
corresponding to residues from the group consisting of V36, Q37,
L38, L49, E57, C79, K93, and S96 in the human BTLA sequence set
forth at Genbank accession no. AAP44003.1 (SEQ ID NO: 64).
[0395] In one embodiment, a BTLA-HVEM agonist is capable of binding
to a polypeptide having at least about 80%, more preferably 85%,
more preferably 90%, more preferably 95% identity to the amino acid
sequence set forth by residues 37-47, 39-49, 41-49, 50-60, 58-68,
80 90, 97-107, 50-90, 55-85, 58-90, 63-85, 80-107, 85-102, 127-137,
55-102, 50-107, and 41-137 of murine C57BL/6 BTLA (SEQ ID NO:
63).
[0396] In one embodiment, a BTLA-HVEM agonist is capable of binding
to a polypeptide selected from the group consisting of the amino
acid sequences set forth by residues 37-47, 39 49, 41-49, 50-60,
58-68, 80-90, 97-107, 50-90, 55-85, 58-90, 63-85, 80-107, 85-102,
127-137, 55-102, 50-107, and 41-137 of murine C57BL/6 BTLA (SEQ ID
NO: 63).
[0397] In one embodiment, a BTLA-HVEM agonist is capable of binding
to a polypeptide having at least about 80%, more preferably 85%,
more preferably 90%, more preferably 95% identity to the amino acid
sequence set forth by residues 31-41, 32-42, 35-43, 44-54, 52-62,
74 84, 88-98, 44-84, 49-79, 52-84, 57-79, 74-98, 79-93, 118-128,
49-93, 44-98, 35-98, and 35-128 of the human BTLA isoform found at
Genbank accession no. AAP44003.1 (SEQ ID NO: 64).
[0398] In one embodiment, a BTLA-HVEM agonist is capable of binding
to a polypeptide selected from the group consisting of the amino
acid sequences set forth by residues 31-41, 32 42, 35-43, 44-54,
52-62, 74-84, 88-98, 44-84, 49-79, 52-84, 57-79, 74-98, 79-93,
118-128, 49-93, 44-98, 35-98, and 35-128 of the human BTLA isoform
found at Genbank accession no. AAP44003.1 (SEQ ID NO: 64).
[0399] In one embodiment, a BTLA-HVEM agonist is capable of
competing with CMV UL144 for binding to BTLA.
[0400] In one embodiment, a BTLA-HVEM agonist is a BTLA
antibody.
[0401] In one aspect, the invention provides BTLA-HVEM agonists
that comprise an HVEM CRD1 domain or fragment thereof capable of
binding to a BTLA Ig domain and stimulating BTLA activity. In
another aspect, the invention provides BTLA-HVEM agonists that
consist essentially of an HVEM CRD1 domain or fragment thereof
capable of binding to a BTLA Ig domain and stimulating BTLA
activity.
[0402] Accordingly, in a preferred embodiment, the invention
provides BTLA-HVEM agonists that are agonistic HVEM fusion proteins
which are capable of binding to a BTLA Ig domain, reducing the
binding of the BTLA Ig domain to an HVEM CRD1 domain, and
stimulating BTLA activity. Such agonistic HVEM fusion proteins lack
an HVEM CRD2 and/or CRD3 domain. Preferred agonistic HVEM fusion
proteins can compete with a BTLA antibody disclosed herein for
binding to a BTLA Ig domain.
[0403] In another preferred embodiment, the invention provides
BTLA-HVEM agonists that are agonistic HVEM protein fragments which
are capable of binding to a BTLA Ig domain, reducing the binding of
the BTLA Ig domain to an HVEM CRD1 domain, and stimulating BTLA
activity. Such agonistic HVEM protein fragments lack an HVEM CRD2
and/or CRD3 domain. In a preferred embodiment, an agonistic HVEM
protein fragment consists essentially of an HVEM CRD1 domain of
fragment thereof which is capable of binding to a BTLA Ig domain
and stimulating BTLA activity. Preferred agonistic HVEM protein
fragments can compete with a BTLA antibody disclosed herein for
binding to a BTLA Ig domain.
[0404] In one embodiment, a BTLA-HVEM agonist is capable of
increasing tyrosine phosphorylation on the intracellular domain of
BTLA protein in a cell having BTLA protein on its surface.
[0405] In one embodiment, a BTLA-HVEM agonist is capable of
increasing association of BTLA protein with SHP-2, PI3K, or Grb2 in
a cell having BTLA protein on its surface.
[0406] In one embodiment, a BTLA-HVEM agonist is capable of
decreasing proliferation of a cell having BTLA protein on its
surface.
[0407] In one embodiment, a BTLA-HVEM agonist is capable of
decreasing IL-2 production by a cell having BTLA protein on its
surface.
[0408] In one embodiment, a BTLA-HVEM agonist is capable of
decreasing antibody production by a cell having said BTLA protein
on its surface.
[0409] In one embodiment, a BTLA-HVEM antagonist is capable of
decreasing the cytotoxicity of a cell having said BTLA protein on
its surface.
(V) Additional Therapeutic Agents
[0410] In a further embodiment, the bioactive agents disclosed
herein may be advantageously combined with one or more additional
therapeutic agents.
[0411] In one aspect, the antagonists and blocking agents described
herein can be administered in combination with additional immune
response stimulating agents such as, e.g., cytokines as well as
various antigens and vaccine preparations including tumor antigens
and tumor vaccines. In preferred embodiments, such cytokines
stimulate antigen presenting cells, e.g., GM-CSF, M-CSF, G-CSF,
IL-3, IL-12, etc. Additional proteins and/or cytokines known to
enhance T cell proliferation and secretion, such as IL-2, IL-2, B7,
anti-CD3 and anti-CD28 can be employed simultaneously or
sequentially with the blocking agents to augment the immune
response. The subject therapy may also be combined with the
transfection or transduction of tumor cells with genes encoding for
various cytokines or cell surface receptors, as is known in the
art. See, e.g. Ogasawara et al. (1993) Cancer Res. 53:3561-8 and
Townsend et al. (1993) Science 259:368-370.
[0412] In another aspect, the agonists and mimicking agents as
described herein can be administered in combination with other
immunosuppressive agents, e.g., antibodies against other immune
cell surface markers (e.g., CD40) or against cytokines, other
fusion proteins, e.g., CTLA4Ig, or other immunosuppressive drugs
(e.g., cyclosporin A, FK506-like compounds, rapamycin compounds, or
steroids).
[0413] It is further contemplated that the subject compositions and
methods may be synergistically combined with immunotherapies based
on modulation of other positive and negative costimulatory
pathways, and with CTLA-4 modulation in particular. For example,
BTLA-HVEM antagonists may be advantageously combined with CTLA-4
blocking agents as described in U.S. Pat. Nos. 5,855,887;
5,811,097; and 6,051,227, and International Publication WO
00/32231. Such CTLA-4 blocking agents inhibit T cell
down-regulation mediated by CTLA-4 interaction with B7 family
members B71 and B72 expressed on lymphoid and dendritic cells.
Similarly, BTLA-HVEM agonists may be advantageously combined with
CTLA-4 mimicking agents such as CTLA-41g, which has already found
clinical use as an immunosuppressive agent.
[0414] As used herein the term "rapamycin compound" includes the
neutral tricyclic compound rapamycin, rapamycin derivatives,
rapamycin analogs, and other macrolide compounds which are thought
to have the same mechanism of action as rapamycin (e.g., inhibition
of cytokine function). The language "rapamycin compounds" includes
compounds with structural similarity to rapamycin, e.g., compounds
with a similar macrocyclic structure, which have been modified to
enhance their therapeutic effectiveness. Exemplary Rapamycin
compounds suitable for use in the invention, as well as other
methods in which Rapamycin has been administered are known in the
art (See, e.g. WO 95/22972, WO 95/16691, WO 95/04738, U.S. Pat.
Nos. 6,015,809; 5,989,591; U.S. Pat. Nos. 5,567,709; 5,559,112;
5,530,006; 5,484,790; 5,385,908; 5,202,332; 5,162,333; 5,780,462;
5,120,727).
[0415] The language "FK506-like compounds" includes FK506, and
FK506 derivatives and analogs, e.g., compounds with structural
similarity to FK506, e.g., compounds with a similar macrocyclic
structure which have been modified to enhance their therapeutic
effectiveness. Examples of FK506 like compounds include, for
example, those described in WO 00/01385. Preferably, the language
"rapamycin compound" as used herein does not include FK506-like
compounds.
[0416] Another preferred embodiment of candidate nucleic acids are
double stranded RNA capable of inducing RNA interference or RNAi
(Bosher, J. M. et al. (2000) Nat. Cell Biol. 2: E31-36).
Introducing double stranded RNA can trigger specific degradation of
homologous RNA sequences, generally within the region of identity
of the dsRNA (Zamore, P. D. et. al. (1997) Cell 101: 25-33). This
provides a basis for silencing expression of genes, thus permitting
a method for altering the phenotype of cells.
[0417] The dsRNA may comprise synthetic RNA made either by known
chemical synthetic methods or by in vitro transcription of nucleic
acid templates carrying promoters (e.g., T7 or SP6 promoters).
Alternatively, the dsRNAs are expressed in vivo, preferably by
expression of palindromic fusion nucleic acids, that allow facile
formation of dsRNA in the form of a hairpin when expressed in the
cell. The double strand regions of the iRNA are generally about
10-500 basepairs or more, preferably 15-200 basepairs, and most
preferably 20-100 basepairs.
(VI) Methods
[0418] The disclosure provides methods for modulating BTLA activity
which involve the use of BTLA-HVEM agonists BTLA-B7x agonists,
BTLA-HVEM antagonists or BTLA-B7x antagomists described herein.
[0419] In one aspect, the invention provides methods for decreasing
BTLA activity, comprising contacting BTLA or HVEM with a BTLA-HVEM
antagonist.
[0420] In a preferred embodiment, the method comprises contacting a
cell having BTLA on its surface with a BTLA-HVEM antagonist,
wherein the cell is capable of contacting HVEM protein in the
absence of the BTLA-HVEM antagonist. In one embodiment, the methods
involve use of a BTLA antibody.
[0421] In a preferred embodiment, the cells having BTLA on their
surface are lymphocytes, NK cells, or macrophages.
[0422] In another embodiment, the method comprises contacting HVEM
protein with a BTLA-HVEM antagonist, wherein the HVEM protein is
capable of contacting a cell having BTLA on its surface in the
absence of the BTLA-HVEM antagonist. In one embodiment, the methods
involve use of an HVEM antibody.
[0423] In a preferred embodiment, the HVEM protein is on the
surface of a dendritic cell or a lymphocyte.
[0424] In another embodiment, the invention provides methods for
decreasing BTLA activation by a BTLA ligand that is capable of
competing with HVEM for binding to BTLA, which comprise the use of
a BTLA-HVEM antagonist. In one embodiment, the BTLA ligand is CMV
UL144.
[0425] In one aspect, the invention provides methods for increasing
BTLA activity comprising contacting a cell having BTLA on its
surface with a BTLA-HVEM agonist. In one embodiment, the methods
involve use of a BTLA antibody.
[0426] In a preferred embodiment, the cells having BTLA on their
surface are lymphocytes, NK cells, or macrophages.
[0427] In one aspect, the invention provides methods for modulating
lymphocyte activation which involve the use of BTLA-HVEM agonists
or BTLA-HVEM antagonists described herein.
[0428] In one aspect, the invention provides methods for increasing
lymphocyte activation. In one embodiment, the methods comprise
contacting a lymphocyte having BTLA on its surface with a BTLA-HVEM
antagonist, wherein the lymphocyte is capable of contacting HVEM
protein in the absence of the BTLA-HVEM antagonist. In one
embodiment, the methods involve use of a BTLA antibody.
[0429] In one embodiment, the methods involve contacting HVEM
protein with a BTLA-HVEM antagonist, wherein the HVEM protein is
capable of contacting a lymphocyte having BTLA on its surface in
the absence of the BTLA-HVEM antagonist. In one embodiment, the
methods involve use of a HVEM antibody.
[0430] In a preferred embodiment, a lymphocyte in which activation
is increased is selected from the group consisting of naive T
cells, CM+ T cells, CD4+ T cells, TH1 cells, naive B cells, and
plasma cells.
[0431] In another embodiment, the invention provides methods for
decreasing lymphocyte activation, comprising contacting a
lymphocyte having BTLA on its surface with a BTLA-HVEM agonist. In
one embodiment, the Methods involve use of a BTLA antibody.
[0432] In a preferred embodiment, a lymphocyte in which activation
is decreased is selected from the group consisting of naive T
cells, CD8+ T cells, CD4+ T cells, TH1 cells, naive B cells, and
plasma cells.
[0433] In one aspect, the invention provides methods for modulating
lymphocyte effector activity.
[0434] In one aspect, the invention provides methods for decreasing
lymphocyte effector activity, comprising contacting a lymphocyte
having BTLA on its surface with a BTLA-HVEM agonist. In one
embodiment, the methods involve the use of a BTLA antibody.
Decreasing lymphocyte effector activity includes promoting the
termination of effector activity, i.e., shortening the duration of
effector activity.
[0435] In one aspect, the invention provides methods for increasing
and/or prolonging lymphoctye effector activity, comprising
contacting a lymphocyte having BTLA on its surface with a BTLA-HVEM
antagonist. In one embodiment, the methods involve the use of a
BTLA antibody. In another embodiment, the methods involve
contacting an HVEM protein with a BTLA-HVEM antagonist. Prolonging
effector activity includes delaying the termination of effector
activity.
[0436] In another aspect, the invention provides methods for
modulating an immune response to an antigen, which involve the use
of BTLA-HVEM agonists or BTLA-HVEM antagonists described
herein.
[0437] In one aspect, the invention provides methods for increasing
an immune response to an antigen, comprising contacting a
lymphocyte having BTLA on its surface with a BTLA-HVEM antagonist,
wherein the lymphocyte has specificity for the antigen, and wherein
the lymphocyte is capable of contacting HVEM protein in the absence
of the BTLA-HVEM antagonist. In one embodiment, the methods involve
use of a BTLA antibody.
[0438] In another embodiment, the methods comprise contacting HVEM
protein with a BTLA-HVEM antagonist, wherein the HVEM protein is
capable of contacting a lymphocyte having BTLA on its surface in
the absence of the BTLA-HVEM antagonist, wherein the lymphocyte has
specificity for the antigen. In one embodiment, the methods involve
use of a HVEM antibody.
[0439] In a preferred embodiment, the antigen is a cancer cell
antigen.
[0440] In another preferred embodiment, the antigen is a viral
antigen.
[0441] In another preferred embodiment, the antigen is presented by
a pathogen.
[0442] In another preferred embodiment, the antigen is provided by
a vaccine.
[0443] In a preferred embodiment, the lymphocyte having BTLA on its
surface and specificity for the antigen is contacted with a
BTLA-HVEM antagonist in vivo.
[0444] In a preferred embodiment, the HVEM protein is contacted
with a BTLA-HVEM antagonist in vivo.
[0445] In a preferred embodiment, the lymphocyte having specificity
for the antigen is selected from the group consisting of naive T
cells, CD8+ T cells, CD4+ T cells, TH1 cells, naive B cells, and
plasma cells.
[0446] In one embodiment, the methods further comprise
administering antigen to a patient receiving the BTLA-HVEM
antagonist.
[0447] In one embodiment, the methods further comprise
administering a bioactive agent that increases a positive
costimulatory signal to a patient receiving the BTLA-HVEM
antagonist.
[0448] In one embodiment, the methods further comprise
administering a bioactive agent that decreases a negative
costimulatory signal to a patient receiving the BTLA-HVEM
antagonist. For example, it is contemplated that use of a BTLA-HVEM
antagonist will be synergistic in combination with agents capable
of providing CTLA-4 blockade as described in U.S. Pat. Nos.
5,855,887; 5,811,097; and 6,051,227, and International Publication
WO 00/32231, the disclosures of which are expressly incorporated
herein by reference.
[0449] In one embodiment, the invention provides methods for
increasing an immune reaction against a tumor in a patient,
comprising contacting a lymphocyte having BTLA on its surface with
a BTLA-HVEM antagonist, wherein the lymphocyte has specificity for
a cancer cell antigen associated with the tumor and is capable of
contacting HVEM protein. In one embodiment, the methods involve use
of a BTLA antibody.
[0450] In another embodiment, the methods comprise contacting HVEM
protein with a BTLA-HVEM antagonist, wherein the HVEM protein is
capable of contacting a lymphocyte having BTLA on its surface, and
wherein the lymphocyte has specificity for a cancer cell antigen
associated with the tumor. In one embodiment, the methods involve
use of a HVEM antibody.
[0451] In a preferred embodiment, the methods further comprise
administering a cancer cell antigen to the patient.
[0452] In a preferred embodiment, the methods further comprise
administering a bioactive agent that increases a positive
costimulatory signal.
[0453] In a preferred embodiment, the methods further comprise
administering a bioactive agent that decreases a negative
costimulatory signal to the cancer patient. For example, it is
contemplated that use of a BTLA-HVEM antagonist will be synergistic
in combination with agents capable of providing CTLA-4 blockade as
described in U.S. Pat. Nos. 5,855,887; 5,811,097; and 6,051,227,
and International Publication WO 00/32231.
[0454] In a preferred embodiment, the lymphocyte having BTLA on its
surface and specificity for the cancer cell antigen is contacted
with a BTLA-HVEM antagonist in vivo.
[0455] In a preferred embodiment, the HVEM protein is contacted
with a BTLA-HVEM antagonist in vivo.
[0456] In a preferred embodiment, the lymphocyte having specificity
for the cancer cell antigen is selected from the group consisting
of naive T cells, CD8+ T cells, CD4+ T cells, `TH1 cells, naive B
cells, and plasma cells.
[0457] In one aspect, the invention provides methods for inhibiting
tumor growth, comprising administering to a patient a
therapeutically effective amount of a BTLA-HVEM antagonist.
[0458] In a preferred embodiment, the methods further comprise
administering a cancer cell antigen to the patient.
[0459] In a preferred embodiment, the methods further comprise
administering a bioactive agent that increases a positive
costimulatory signal.
[0460] In a preferred embodiment, the methods further comprise
administering a bioactive agent that decreases a negative
costimulatory signal to the cancer patient. For example, it is
contemplated that use of a BTLA-HVEM antagonist will be synergistic
in combination with agents capable of providing CTLA-4 blockade as
described in U.S. Pat. Nos. 5,855,887; 5,811,097; and 6,051,227,
and International Publication WO 00/32231.
[0461] In one aspect, the invention provides methods for treating
cancer, comprising administering to a patient a therapeutically
effective amount of a BTLA-HVEM antagonist.
[0462] In a preferred embodiment, the methods further comprise
administering a cancer cell antigen to the patient.
[0463] In a preferred embodiment, the methods further comprise
administering a bioactive agent that increases a positive
costimulatory signal.
[0464] In a preferred embodiment, the methods further comprise
administering a bioactive agent that decreases a negative
costimulatory signal to the cancer patient. For example, it is
contemplated that use of a BTLA-HVEM antagonist will be synergistic
in combination with agents capable of providing CTLA-4 blockade as
described in U.S. Pat. Nos. 5,855,887; 5,811,097; and 6,051,227,
and International Publication WO 00/32231.
[0465] In one aspect, the invention provides methods for reducing
an immune response to an antigen, comprising contacting a
lymphocyte having BTLA on its surface with a BTLA-HVEM agonist,
wherein the lymphocyte has specificity for the antigen. In one
embodiment, the methods involve use of a BTLA antibody.
[0466] In a preferred embodiment, the antigen is a graft cell
antigen.
[0467] In another preferred embodiment, the antigen is a self
antigen.
[0468] In another preferred embodiment, the lymphocyte having
specificity for the antigen is selected from the group consisting
of naive T cells, CD8+ T cells, CD4+ T cells, TH1 cells, naive B
cells, and plasma cells.
[0469] In one embodiment, the methods further comprise
administering a bioactive agent that decreases a positive
costimulatory signal to the patient.
[0470] In one embodiment, the methods further comprise
administering an immunosuppressant to the patient.
[0471] In one embodiment, the methods further comprise
administering a bioactive agent that increases a negative
costimulatory signal to the patient.
[0472] In one embodiment, the invention provides methods for
reducing an immune reaction against a graft in a patient,
comprising contacting a lymphocyte having BTLA on its surface with
a BTLA HVEM agonist, wherein the lymphocyte has specificity for a
graft cell antigen. In one embodiment, the BTLA-HVEM agonist is a
BTLA antibody.
[0473] In another preferred embodiment, the lymphocyte having
specificity for the antigen is selected from the group consisting
of naive T cells, CD8 T cells, CD4+ T cells, TH1 cells, naive B
cells, and plasma cells.
[0474] In one embodiment, the methods further comprise
administering a bioactive agent that decreases a positive
costimulatory signal to the patient.
[0475] In one embodiment, the methods further comprise
administering an immunosuppressant to the patient.
[0476] In one embodiment, the methods further comprise
administering a bioactive agent that increases a negative
costimulatory signal to the patient.
[0477] In one aspect, the invention provides methods for reducing
rejection of a graft by a patient, comprising administering to the
patient a therapeutically effective amount of a BTLA-HVEM
agonist.
[0478] In one embodiment, the methods further comprise
administering a bioactive agent that decreases a positive
costimulatory signal to the patient.
[0479] In one embodiment, the methods further comprise
administering an immunosuppressant to the patient.
[0480] In one embodiment, the methods further comprise
administering a bioactive agent that increases a negative
costimulatory signal to the patient.
[0481] In one aspect, the invention provides methods for prolonging
the survival of a graft in a patient, comprising administering to
the patient a therapeutically effective amount of a BTLA-HVEM
agonist.
[0482] In one embodiment, the methods further comprise
administering a bioactive agent that decreases a positive
costimulatory signal to the patient.
[0483] In one embodiment, the methods further comprise
administering an immunosuppressant to the patient.
[0484] In one embodiment, the methods further comprise
administering a bioactive agent that increases a negative
costimulatory signal to the patient.
[0485] In one aspect, the invention provides methods for reducing a
graft versus host response in a patient, comprising administering
to the patient a therapeutically effective amount of a BTLA-HVEM
antagonist.
[0486] In one embodiment, the methods further comprise
administering a bioactive agent that increases a positive
costimulatory signal to the patient.
[0487] In one embodiment, the methods further comprise
administering a bioactive agent that decreases a negative
costimulatory signal to the patient. For example, it is
contemplated that use of a BTLA-HVEM antagonist will be synergistic
in combination with agents capable of activating CTLA-4 as
described in U.S. Pat. Nos. 5,855,887; 5,811,097; and 6,051,227,
and International Publication WO 00/32231.
[0488] In one aspect, the invention provides methods for treating a
patient having an autoimmune disease, comprising administering to
the patient a therapeutically effective amount of a BTLA-HVEM
agonist.
[0489] In one embodiment, the autoimmune disease is selected from
the group consisting of Rheumatoid arthritis, type 1 diabetes,
autoimmune thyroiditis, and Lupus.
[0490] In one embodiment, the methods further comprise
administering a bioactive agent that decreases a positive
costimulatory signal to the patient.
[0491] In one embodiment, the methods further comprise
administering an immunosuppressant to the patient.
[0492] In one embodiment, the methods further comprise
administering a bioactive agent that increases a negative
costimulatory signal to the patient.
[0493] In one aspect, the invention provides methods for treating a
patient having an allergic reaction, comprising administering to
the patient a therapeutically effective amount of a BTLA-HVEM
agonist.
[0494] In one aspect, the invention provides methods for preventing
a patient from having an allergic reaction, comprising
administering to the patient a therapeutically effective amount of
a BTLA-HVEM agonist.
[0495] In one aspect, the invention provides methods for reducing
an allergic reaction in a patient, comprising administering to the
patient a therapeutically effective amount of a BTLA-HVEM
agonist.
[0496] In one aspect, the invention provides methods for reducing
an asthmatic response in a patient, comprising administering to the
patient a therapeutically effective amount of a BTLA-HVEM
agonist.
[0497] In one aspect, the invention provides methods for enhancing
recovery from an asthmatic response in a patient, comprising
administering to the patient a therapeutically effective amount of
a BTLA-HVEM agonist.
[0498] In one aspect, the invention provides methods for treating
asthma, comprising administering to an asthma patient a
therapeutically effective amount of a BTLA-HVEM agonist.
[0499] In one aspect, the invention provides methods for reducing
an inflammatory reaction in a patient, comprising administering to
the patient a therapeutically effective amount of a BTLA-HVEM
agonist.
[0500] In one aspect, the invention provides methods for reducing
the interaction of cell having BTLA on its surface and a second
cell having HVEM on its surface. The methods involve the use of a
BTLA-HVEM antagonist or a BTLA-HVEM agonist. In a preferred
embodiment, the methods involve use of a BTLA antibody or a HVEM
antibody. In a preferred embodiment, the cell having BTLA on its
surface is selected from the group consisting of naive T cells,
CD8+ T cells, CD4+ T cells, TH1 cells, naive B cells, and plasma
cells.
[0501] In one aspect, the invention provides methods for modulating
memory cell formation, comprising contacting a lymphocyte exposed
to antigen with a BTLA-HVEM agonist or antagonist. In a preferred
embodiment, the methods involve the use of a BTLA antibody.
[0502] In one aspect, the invention provides methods for modulating
tolerance of self antigen, comprising contacting a lymphocyte
exposed to self antigen with a BTLA-HVEM agonist or antagonist. In
a preferred embodiment, the methods involve the use of a BTLA
antibody.
[0503] Also provided are adjuvant compositions comprising at least
one of the BTLA-HVEM antagonists described herein.
[0504] Also provided are immunosuppressant compositions comprising
at least one of the BTLA-HVEM agonists described herein.
[0505] In another aspect, the present invention provides methods of
screening for BTLA-HVEM agonists and BTLA-HVEM antagonists, which
agonists and antagonists find therapeutic uses for the modulation
of immune reactions.
[0506] The invention further contemplates the use of the
aforementioned polypeptides in immunoassays.
[0507] The invention further contemplates the use of the
aforementioned polypeptides as immunogens for the production of
antibodies.
Gene Therapy
[0508] In a further aspect, the present invention provides
compositions and methods for gene therapy.
[0509] Nucleic acids encoding HVEM, B7x or BTLA polypeptides, as
well as genetic antagonists or agonists of HVEM, BTLA or B7x, may
be used in gene therapy. In gene therapy applications, genes are
introduced into cells in order to achieve in vivo synthesis of a
therapeutically effective genetic product, for example for
replacement of a defective gene. "Gene therapy" includes both
conventional gene therapy where a lasting effect is achieved by a
single treatment, and the administration of gene therapeutic
agents, which involves the one time or repeated administration of a
therapeutically effective DNA or mRNA. Antisense RNAs and DNAs can
be used as therapeutic agents for blocking the expression of
certain genes in vivo. It has already been shown that short
antisense oligonucleotides can be imported into cells where they
act as inhibitors, despite their low intracellular concentrations
caused by their restricted uptake by the cell membrane. (Zamecnik
et al., Proc. Natl. Acad. Sci. USA 83, 4143-4146 [1986]). The
oligonucleotides can be modified to enhance their uptake, e.g. by
substituting their negatively charged phosphodiester groups by
uncharged groups.
[0510] There are a variety of techniques available for introducing
nucleic acids into viable cells. The techniques vary depending upon
whether the nucleic acid is transferred into cultured cells in
vitro, or in vivo in the cells of the intended host. Techniques
suitable for the transfer of nucleic acid into mammalian cells in
vitro include the use of liposomes, electroporation,
microinjection, cell fusion, DEAE-dextran, the calcium phosphate
precipitation method, etc. The currently preferred in vivo gene
transfer techniques include transfection with viral (typically
retroviral) vectors and viral coat protein-liposome mediated
transfection (Dzau et al., Trends in Biotechnology 11, 205-210
[1993]). In some situations it is desirable to provide the nucleic
acid source with an agent that targets the target cells, such as an
antibody specific for a cell surface membrane protein or the target
cell, a ligand for a receptor on the target cell, etc. Where
liposomes are employed, proteins which bind to a cell surface
membrane protein associated with endocytosis may be used for
targeting and/or to facilitate uptake, e.g. capsid proteins or
fragments thereof tropic for a particular cell type, antibodies for
proteins which undergo internalization in cycling, proteins that
target intracellular localization and enhance intracellular
half-life. The technique of receptor-mediated endocytosis is
described, for example, by Wu et al., J. Biol. Chem. 262, 4429-4432
(1987); and Wagner et al., Proc. Natl. Acad. Sci. USA 87, 3410-3414
(1990). For review of gene marking and gene therapy protocols see
Anderson et al., Science 256, 808-813 (1992).
Diagnostic Uses
[0511] Mutations, deletions, duplications, and/or rearrangements
that decrease B7x expression and/or activity lead to a loss of
signaling that normally inhibits T cell activation. These may be
germline or somatic changes. The functional consequence of this
loss of inhibition is a hyperimmune state, characterized by
autoimmune disease. Particularly affected are those tissues that
harbor cells with the mutation and that show high levels of B7x
expression normally, such as kidney, placenta, liver, lung and
heart. The clinical manifestations of such B7x mutations may
include autoimmune disorders such as e.g., diabetes, pre-eclampsia,
rheumatoid arthritis, multiple sclerosis, and the like.
[0512] Similarly, mutations, deletions, duplications, and/or
rearrangements that decrease BTLA expression and/or activity lead
to a loss of signaling that normally inhibits T cell activation.
These may be germline or somatic changes. The functional
consequence of this loss of inhibition is a hyperimmune state,
characterized by autoimmune disease. Particularly affected are
tissues that harbor antigens with which the affected T cells react,
and that show high levels of B7x expression normally, such as
kidney, placenta, liver, lung and heart. The clinical
manifestations of such BTLA mutations may include autoimmune
disorders.
[0513] In a preferred embodiment, the invention provides methods of
diagnosing an autoimmune predisposition and/or disease. The methods
involve measuring the expression and/or activity of HVEM, BTLA
and/or B7x.
[0514] Mutations, deletions, duplications, and/or rearrangements
that increase B7x expression and/or activity lead to an increase in
signaling that normally inhibits T cell activation. These may be
germline or somatic changes. The functional consequence of this
increase in inhibitory signaling is a hypoimmune state,
characterized by undesired cell growth and undesired cell
survival.
[0515] As identified herein, B7x is highly expressed in a number of
tumor cells. The high level of B7x expression allows such tumor
cells to inhibit a T cell immune response that would otherwise be
mounted against the tumor tissue.
[0516] Similarly, mutations, deletions, duplications, and/or
rearrangements that increase BTLA expression and/or activity lead
to an increase in signaling that normally inhibits T cell
activation. These may be germline or somatic changes. The
functional consequence of this increase in inhibitory signaling is
a hypoimmune state, characterized by undesired cell growth,
undesired cell survival, and increased susceptibility to disease
caused by pathogens.
[0517] In one embodiment, the present invention provides methods of
diagnosing a predisposition to cancer, or the existence or
recurrence of cancer. The methods involve measuring the expression
and/or activity of HVEM, BTLA and/or B7x, either generally or in a
tissue-specific fashion.
Modulation of Immune Responses
[0518] The present invention provides methods for modulating
lymphocyte activity and immune responses to antigens using
BTLA-HVEM antagonists, BTLA-HVEM agonists, BTLA-B7x antagonists,
and BTLA-B7x agonists described herein. The methods are useful for
modulating the activity of, for example, naive T cells, CD8+ Tc
cells, CD4+ cells, TH1 cells, and B cells.
[0519] Surprisingly, also demonstrated herein is the expression of
BTLA on activated B cells and its ability to inhibit B cell
activity. B cells from mice lacking BTLA function exhibit increased
responses to stimulation with anti-IgM, and BTLA deficient mice
exhibit a three-fold increase in the amount of specific IgG1,
IgG2a, and IgG2b isotypes as compared with control littermates.
These observations are the first evidence of an inhibitory B cell
activity for BTLA, which enables the use of agents that are capable
of modulating BTLA activity to modulate B cell activity and
antibody production. Accordingly, the invention also provides
compositions and methods for modulating B cell activity and
antibody production, which involve the use of agents capable of
modulating BTLA activity.
[0520] Included among the preferred bioactive agents are B7x
antibodies (anti-B7x antibodies), HVEM antibodies (anti-HVEM
antibodies), BTLA antibodies (anti-BTLA antibodies), B7x fusion
proteins, HVEM fusion proteins, BTLA fusion proteins, B7x proteins
and fragments, HVEM proteins and fragments, BTLA proteins and
fragments, peptides, and small molecule chemical compositions.
Agonists of BTLA-mediated signaling, such as B7x proteins, B7x
fusion proteins, and function activating anti-BTLA antibodies, may
be used to stimulate BTLA and inhibit T and B cell activity.
Conversely, antagonists of BTLA-mediated signaling, such as BTLA-Ig
fusion proteins, function blocking anti-BTLA antibodies, function
blocking anti-HVEM antibodies, and anti-B7x antibodies, may be used
to inhibit BTLA-mediated signaling, thereby preventing the
attenuation of T and B cell activity mediated by BTLA signaling
and, preferably, increasing T and B cell activity.
[0521] The anti-B7x antibodies provided herein specifically bind to
B7x protein, and in particular, to one or more epitopes present in
the extracellular domain of B7x identified above. The anti-BTLA
antibodies provided herein specifically bind to BTLA protein, and
in particular, to one or more epitopes present in the extracellular
domain of BTLA identified above. The anti-HVEM antibodies provided
herein specifically bind to HVEM protein, and in particular, to one
or more epitopes present in the extracellular domain of HVEM
identified above. Preferably, these antibodies effectively inhibit
or interfere with the natural interaction between HVEM or B7x with
BTLA.
[0522] By inhibiting the interaction of BTLA and B7x, anti-B7x
antibodies are used in a preferred embodiment to inhibit the
suppression and/or attenuation of lymphocyte activity mediated by
BTLA signaling.
[0523] Blocking anti-BTLA antibodies and anti-HVEM antibodies are
used in a preferred embodiment to inhibit the suppression and/or
attenuation of lymphocyte activity mediated by BTLA signaling. In
an alternative embodiment, a function activating anti-BTLA antibody
or anti-HVEM antibody is used to stimulate BTLA and promote the
suppression and/or attenuation of lymphocyte activity mediated by
BTLA signaling.
[0524] The present invention provides methods of screening for
bioactive agents capable of modulating the natural interaction
between B7x and BTLA or HVEM and BTLA. In a preferred embodiment,
the methods involve providing a B7x protein, a BTLA protein, and a
candidate agent, and determining the binding of B7x to BTLA in the
presence of the candidate agent. Agents that interfere with the
binding of BTLA to B7x find use as antagonists of the natural
interaction of BTLA-expressing and B7x-expressing cells.
Accordingly, such agents find use as modulators of T cell
activation. In some cases, an agent may mimic the action of B7x
towards BTLA, or the action of BTLA towards B7x. In another
preferred embodiment, the methods involve providing a HVEM protein,
a BTLA protein, and a candidate agent, and determining the binding
of HVEM to BTLA in the presence of the candidate agent. Agents that
interfere with the binding of BTLA to HVEM find use as antagonists
of the natural function of BTLA. Accordingly, such agents find use
as modulators of T cell activation. In some cases, an agent may
mimic the action of HVEM towards BTLA, or the action of BTLA
towards HVEM.
[0525] BTLA-HVEM or B7x-BTLA antagonists are used alone or in
combination with other therapeutic agents to reduce the negative
costimulatory signals emitted by BTLA, and to reduce the
suppression and/or attenuation of lymphocyte activity mediated by
BTLA signaling.
[0526] BTLA-HVEM or B7x-BTLA agonists are used are used alone or in
combination with other therapeutic agents to increase negative
costimulatory signals emitted by BTLA, thereby increasing the
suppression and/or attenuation of lymphocyte activity mediated by
BTLA signaling.
[0527] In a preferred embodiment, the methods comprise contacting a
lymphocyte expressing BTLA on its surface, or a second cell
expressing HVEM on its surface, or both, with a BTLA-HVEM
antagonist, wherein the lymphocyte and second cell are able to
contact each other such that BTLA on the lymphocyte can bind to
HVEM on the second cell, and wherein the BTLA-HVEM antagonist
reduces the activation of BTLA on the lymphocyte by HVEM on the
second cell.
[0528] In another preferred embodiment, the methods comprise
contacting a lymphocyte expressing BTLA on its surface with a
BTLA-HVEM agonist, such that the BTLA-HVEM agonist increases BTLA
activity in the lymphocyte.
[0529] In one aspect, the present invention provides a medicament
for the treatment of diseases associated with lymphocyte
activity.
Antigens
[0530] As described herein, the compositions and methods provided
herein find use in modulating lymphocyte activity in response to
antigenic stimulation. Such antigenic stimulation can come from
tumor-associated antigens, pathogen antigens and autoantigens.
Antigenic stimulation caused by tumor-associated antigens and
pathogen antigens may be a result of on-going malignancy or
infection, and/or may be a result of vaccine antigens.
[0531] A wide variety of antigens may find use in conjunction with
the compositions and formulations of the present invention. In
particular, the adjuvant compositions provided herein may be
advantageously combined with antigenic stimulation from
tumor-associated antigens or pathogen antigens to increase
lymphocyte activity against the corresponding tumor or pathogen.
Generally, suitable antigens may be derived from proteins,
peptides, polypeptides, lipids, glycolipids, carbohydrates and DNA
found in the subject tumor or pathogen.
[0532] Tumor-associated antigens finding utility herein include
both mutated and non-mutated molecules which may be indicative of a
single tumor type, shared among several types of tumors, and/or
exclusively expressed or over-expressed in tumor cells in
comparison with normal cells. In addition to proteins and
glycoproteins, tumor-specific patterns of expression of
carbohydrates, gangliosides, glycolipids and mucins have also been
documented.
[0533] Exemplary tumor-associated antigens for use in the subject
cancer vaccines include protein products of oncogenes, tumor
suppressor genes and other genes with mutations or rearrangements
unique to tumor cells, reactivated embryonic gene products,
oncofetal antigens, tissue-specific (but not tumor-specific)
differentiation antigens, growth factor receptors, cell surface
carbohydrate residues, foreign viral proteins and a number of other
self proteins.
[0534] Specific embodiments of tumor-associated antigens include,
e.g., mutated antigens such as the protein products of the Ras p21
protooncogenes, tumor suppressor p53 and HER-2/neu and BCR-abl
oncogenes, as well as CDK4, MUM1, Caspase 8, and Beta catenin;
overexpressed antigens such as galectin 4, galectin 9, carbonic
anhydrase, Aldolase A, PRAME, Her2/neu, ErbB-2 and KSA, oncofetal
antigens such as alpha fetoprotein (AFP), human chorionic
gonadotropin (hCG); self antigens such as carcinoembryonic antigen
(CEA) and melanocyte differentiation antigens such as Mart 1/Melan
A, gp100, gp75, Tyrosinase, TRP1 and TRP2; prostate associated
antigens such as PSA, PAP, PSMA, PSM-P1 and PSM-P2; reactivated
embryonic gene products such as MAGE 1, MAGE 3, MAGE 4, GAGE 1,
GAGE 2, BAGE, RAGE, and other cancer testis antigens such as
NY-ESO1, SSX2 and SCP1; mucins such as Muc-1 and Muc-2;
gangliosides such as GM2, GD2 and GD3, neutral glycolipids and
glycoproteins such as Lewis (y) and globo-H; and glycoproteins such
as Tn, Thompson-Freidenreich antigen (TF) and sTn. Also included as
tumor-associated antigens herein are whole cell and tumor cell
lysates as well as immunogenic portions thereof, as well as
immunoglobulin idiotypes expressed on monoclonal proliferations of
B lymphocytes for use against B cell lymphomas.
[0535] Tumor-associated antigens and their respective tumor cell
targets include, e.g., cytokeratins, particularly cytokeratin 8, 18
and 19, as antigens for carcinoma. Epithelial membrane antigen
(EMA), human embryonic antigen (HEA-125), human milk fat globules,
MBr1, MBr8, Ber-EP4, 17-1A, C26 and T16 are also known carcinoma
antigens. Desmin and muscle-specific actin are antigens of myogenic
sarcomas. Placental alkaline phosphatase, beta-human chorionic
gonadotropin, and alpha-fetoprotein are antigens of trophoblastic
and germ cell tumors. Prostate specific antigen is an antigen of
prostatic carcinomas, carcinoembryonic antigen of colon
adenocarcinomas. HMB-45 is an antigen of melanomas. In cervical
cancer, useful antigens could be encoded by human papilloma virus.
Chromagranin-A and synaptophysin are antigens of neuroendocrine and
neuroectodermal tumors. Of particular interest are aggressive
tumors that form solid tumor masses having necrotic areas. The
lysis of such necrotic cells is a rich source of antigens for
antigen-presenting cells, and thus the subject compositions and
methods may find advantageous use in conjunction with conventional
chemotherapy and/or radiation therapy.
[0536] Tumor-associated antigens can be prepared by methods well
known in the art. For example, these antigens can be prepared from
cancer cells either by preparing crude extracts of cancer cells
(e.g., as described in Cohen et al., Cancer Res., 54:1055 (1994)),
by partially purifying the antigens, by recombinant technology, or
by de novo synthesis of known antigens. The antigen may also be in
the form of a nucleic acid encoding an antigenic peptide in a form
suitable for expression in a subject and presentation to the immune
system of the immunized subject. Further, the antigen may be a
complete antigen, or it may be a fragment of a complete antigen
comprising at least one epitope.
[0537] Antigens derived from pathogens known to predispose to
certain cancers may also be advantageously utilized in conjunction
with the compositions and methods provided herein. It is estimated
that close to 16% of the worldwide incidence of cancer can be
attributed to infectious pathogens, and a number of common
malignancies are characterized by the expression of specific viral
gene products. Thus, the inclusion of one or more antigens from
pathogens implicated in causing cancer may help broaden the host
immune response and enhance the prophylactic or therapeutic effect
of the cancer vaccine. Pathogens of particular interest for use
herein include the hepatitis B virus (hepatocellular carcinoma),
hepatitis C virus (heptomas), Epstein Barr virus (EBV) (Burkitt
lymphoma, nasopharynx cancer, PTLD in immunosuppressed
individuals), HTLV1 (adult T cell leukemia), oncogenic human
papilloma viruses types 16, 18, 33, 45 (adult cervical cancer), and
the bacterium Helicobacter pylori (B cell gastric lymphoma).
[0538] Also contemplated herein are pathogen antigens derived from
infectious microbes such as virus, bacteria, parasites and fungi
and fragments thereof, in order to increase lymphocyte activity in
response to active infection or improve the efficacy of
prophylactic vaccine therapy. Examples of infectious virus include,
but are not limited to: Retroviridae (e.g. human immunodeficiency
viruses, such as HIV-1 (also referred to as HTLV-III, LAV or
HTLV-III/LAV, or HIV-III; and other isolates, such as HIV-LP;
Picornaviridae (e.g. polio viruses, hepatitis A virus;
enteroviruses, human Coxsackie viruses, rhinoviruses, echoviruses);
Calciviridae (e.g. strains that cause gastroenteritis); Togaviridae
(e.g. equine encephalitis viruses, rubella viruses); Flaviridae
(e.g. dengue viruses, encephalitis.cndot.viruses, yellow fever
viruses); Coronoviridae (e.g. coronaviruses); Rhabdoviradae (e.g.
vesicular stomatitis viruses, rabies viruses); Coronaviridae (e.g.
coronaviruses); Rhabdoviridae (e.g. vesicular stomatitis viruses,
rabies viruses); Filoviridae (e.g. ebola viruses); Paramyxoviridae
(e.g. parainfluenza viruses, mumps virus, measles virus,
respiratory syncytial virus); Orthomyxoviridae (e.g. influenza
viruses); Bungaviridae (e.g. Hantaan viruses, bunga viruses,
phleboviruses and Nairo viruses); Arena viridae (hemorrhagic fever
viruses); Reoviridae (e.g. reoviruses, orbiviurses and
rotaviruses); Birnaviridae; Hepadnaviridae (Hepatitis B virus);
Parvovirida (parvoviruses); Papovaviridae (papilloma viruses,
polyoma viruses); Adenoviridae (most adenoviruses); Herpesviridae
herpes simplex virus (HSV) 1 and 2, varicella zoster virus,
cytomegalovirus (CMV), herpes virus; Poxyiridae (variola viruses,
vaccinia viruses, pox viruses); and Iridoviridae (e.g. African
swine fever virus); and unclassified viruses (e.g. the etiological
agents of Spongiform encephalopathies, the agent of delta hepatitis
(thought to be a defective satellite of hepatitis B virus), the
agents of non-A, non-B hepatitis (class 1=internally transmitted;
class 2=parenterally transmitted (i.e. Hepatitis C); Norwalk and
related viruses, and astroviruses).
[0539] Also, gram negative and gram positive bacteria serve as
antigens in vertebrate animals. Such gram positive bacteria
include, but are not limited to Pasteurella species, Staphylococci
species, and Streptococcus species. Gram negative bacteria include,
but are not limited to, Escherichia coli, Pseudomonas species, and
Salmonella species. Specific examples of infectious bacteria
include but are not limited to: Helicobacter pyloris, Borelia
burgdorferi, Legionella pneumophilia, Mycobacteria sps (e.g. M.
tuberculosis, M. avium, M. intracellulare, M. kansaii, M.
gordonae), Staphylococcus aureus, Neisseria gonorrhoeae, Neisseria
meningitidis, Listeria monocytogenes, Streptococcus pyogenes (Group
A Streptococcus), Streptococcus agalactiae (Group B Streptococcus),
Streptococcus (viridans group), Streptococcus faecalis,
Streptococcus bovis, Streptococcus (anaerobic sps.), Streptococcus
pneumoniae, pathogenic Campylobacter sp., Enterococcus sp.,
Haemophilus infuenzae, Bacillus antracis, corynebacterium
diphtheriae, corynebacterium sp., Erysipelothrix rhusiopathiae,
Clostridium perfringers, Clostridium tetani, Enterobacter
aerogenes, Klebsiella pneumoniae, Pasturella multocida, Bacteroides
sp., Fusobacterium nucleatum, Streptobacillus moniliformis,
Treponema pallidium, Treponema pertenue, Leptospira, Rickettsia,
and Actinomyces israelli.
[0540] Examples of pathogens also include, but are not limited to,
infectious fungi that infect mammals, and more particularly humans.
Examples of infectious fingi include, but are not limited to:
Cryptococcus neoformans, Histoplasma capsulatum, Coccidioides
immitis, Blastomyces dermatitidis, Chlamydia trachomatis, Candida
albicans. Examples of infectious parasites include Plasmodium such
as Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale,
and Plasmodium vivax. Other infectious organisms (i.e. protists)
include Toxoplasma gondii.
[0541] Other medically relevant microorganisms that serve as
antigens in mammals and more particularly humans are described
extensively in the literature, e.g., see C. G. A Thomas, Medical
Microbiology, Bailliere Tindall, Great Britain 1983, the entire
contents of which is hereby incorporated by reference. In addition
to the treatment of infectious human diseases, the compositions and
methods of the present invention are useful for treating infections
of nonhuman mammals. Many vaccines for the treatment of non-human
mammals are disclosed in Bennett, K. Compendium of Veterinary
Products, 3rd ed. North American Compendiums, Inc., 1995.
Treatment of Autoimmune Disease
[0542] The present invention also provides compositions and methods
for inhibiting autoimmune responses. In a preferred embodiment,
compositions and methods for inhibiting the activity of
autoreactive T and B cells that specifically recognize autoantigens
are provided. Desirably, these compositions and methods may be used
to inhibit killing of non-tumor cells mediated by one or more
autoantigens.
[0543] In preferred embodiments, the methods for inhibiting
autoimmune responses and treating autoimmune diseases, comprising
administering to a patient a therapeutically effective amount of a
BTLA-HVEM agonist. Without being bound by theory, administration of
a therapeutically effective amount of a BTLA-HVEM agonist inhibits
the activity of autoreactive T and B cells that specifically
recognize autoantigens and otherwise negatively affect the
physiology of cells that bear them.
[0544] In other preferred embodiments, compositions for use in the
treatment of autoimmune disease comprise the agonists of
BTLA-mediated signaling described herein including the
above-described mimicking agents. Especially preferred agents
include B7x protein fragments comprising the B7x extracellular
domain, or a portion thereof; B7x-Ig fusion proteins comprising the
B7x extracellular domain, or a portion thereof; function-activating
anti-BTLA antibody; peptides that mimic B7x (mimetics); and small
molecule chemical compositions that mimic the natural interaction
of BTLA and B7x. Also preferred are compositions capable of binding
to both BTLA and TCR, either in a cross-linking fashion or as
polyclonal mixtures.
[0545] Also contemplated in the present invention are genetic
approaches to autoimmune disease. Particularly, gene therapy may be
used to increase the level of BTLA expression on T cells, and/or
increase the level of expression of B7x on non-lymphoid cells that
are subject to attack by autoreactive lymphocytes. The use of
isoforms of BTLA and B7x that exhibit elevated specific activity is
also contemplated, the object of each method being to potentiate
signaling that is suppressive to T cell activation.
[0546] Also provided herein are methods of screening for bioactive
agents that increase the level and/or activity of B7x. Further
provided are methods of screening for bioactive agents that
increase the level and/or activity of BTLA. Also provided are
methods of screening for bioactive agents that increase the level
and/or activity of HVEM. The present invention contemplates the use
of such agents to treat autoimmune diseases, the object being to
potentiate signaling that is suppressive to lymphocyte
activity.
[0547] Autoimmune disease as used herein includes Rheumatoid
arthritis, type 1 diabetes, autoimmune thyroiditis, and Lupus.
Additional autoimmune diseases are described, for example, in
Mackay et al., NEJM, 345:340-350, 2001.
[0548] In one aspect, the present invention provides a medicament
for the treatment of autoimmune disease.
[0549] In one aspect, the present invention provides a medicament
for the treatment of autoimmune disease, wherein the medicament
comprises a BTLA-HVEM agonist. Also provided are methods for making
a medicament useful for the treatment of autoimmune disease, which
medicament comprises a BTLA-HVEM agonist.
[0550] In another aspect, the invention provides methods for
preventing or reducing an allergic reaction in a patient,
comprising administering to a patient a therapeutically effective
amount of a BTLA-HVEM agonist.
[0551] In one aspect, the present invention provides a medicament
for the treatment or prevention of allergy, wherein the medicament
comprises a BTLA-HVEM agonist. Also provided are methods for making
a medicament useful for the treatment or prevention of allergy,
which medicament comprises a BTLA-HVEM agonist.
[0552] In one aspect, the invention provides methods for reducing
the severity of an asthmatic reaction in a patient, comprising
administering to a patient a therapeutically effective amount of a
BTLA-HVEM antagonist.
[0553] In one aspect, the invention provides methods for shortening
the duration of an asthmatic reaction in a patient, comprising
administering to a patient a therapeutically effective amount of a
BTLA-HVEM antagonist.
[0554] In one aspect, the invention provides methods for improving
recovery from an asthmatic reaction in a patient, comprising
administering to a patient a therapeutically effective amount of a
BTLA-HVEM antagonist.
Treatment of Cancer
[0555] The present invention also provides compositions and methods
for treating cancer. In some embodiments, the present invention
provides immunotherapeutic methods for treating cancer, comprising
administering to a patient a therapeutically effective amount of a
BTLA-HVEM antagonist, either alone or in combination with other
therapeutic compositions. In preferred embodiments, immunization is
done to promote a tumor-specific T cell immune response. In this
embodiment, a BTLA-HVEM antagonist is administered in combination
with a tumor-associated antigen. The combination of a
tumor-associated antigen and a BTLA-HVEM antagonist promotes a
tumor specific T cell response, in which T cells encounter reduced
negative costimulatory signals mediated by BTLA as compared to
those in the absence of the BTLA-HVEM antagonist.
[0556] In other embodiments, the present invention also provides
compositions and methods for treating cancer by increasing the
activity of BTLA-positive lymphocytes against B7x-positive tumor
cells. In a preferred embodiment, compositions and methods for
increasing the T cell response to tumor-associated antigens other
than B7x are provided. Desirably, these compositions and methods
may be used to inhibit the growth of tumor cells capable of
expressing B7x.
[0557] In other embodiments, compositions for use in the treatment
of cancer are the antagonists of BTLA-mediated signaling described
herein including, e.g., BTLA, HVEM or B7x blocking agents.
Especially preferred agents include anti-B7x antibodies; protein
fragments comprising the BTLA extracellular domain, or a portion
thereof; BTLA-Ig fusion proteins comprising the BTLA extracellular
domain, or a portion thereof; function-blocking anti-BTLA antibody;
peptides that mimic BTLA (mimetics); and small molecule chemical
compositions that interfere with the natural interaction of BTLA
and B7x.
[0558] Also contemplated in the present invention are genetic
approaches to the treatment of cancer. Particularly, gene therapy
may be used to decrease the level of BTLA expression on T cells,
and/or decrease the level of expression of B7x on tumor cells. The
use of isoforms of BTLA and B7x that exhibit dominant negative
activity is also contemplated, the object of each method being to
inhibit signaling that is normally suppressive to T cell
activation. Genetic approaches may involve the use of tissue and
cell specific promoters to target expression of BTLA and/or B7x
dominant negative variants, antisense nucleic acids, or small
inhibitory RNAs to T cells and tumor cells, respectively. The
methods may additionally involve the use of tumor-targeted viruses,
or other delivery vehicles that specifically recognize tumor cells.
The methods may additionally involve the use of T cell-targeted
viruses, or other delivery vehicles that specifically recognize T
cells.
[0559] Also provided herein are methods of screening for bioactive
agents that decrease the level and/or activity of B7x. Further
provided are methods of screening for bioactive agents that
decrease the level and/or activity of BTLA. The present invention
contemplates the use of such agents to treat cancer, the object
being to inhibit signaling that normally attenuates the lymphocytic
response to tumor antigens and tumor tissues.
[0560] Particularly preferred are agents that may be selectively
targeted to tumor cells, and effect a decrease in B7x expression in
tumor cells without reducing the level of B7x expression in
non-tumor cells to deleterious levels. Highly preferred are agents
that have a precursor form. These "prodrugs" are converted to their
active form in the vicinity of tumor tissue typically by an
enzymatic activity that is restricted in its distribution to the
vicinity of the tumor.
[0561] Also highly preferred are agents that can be combined with
targeting moieties that selectively deliver the agent to a tumor.
These targeting moieties provide a high local concentration of the
agent in the vicinity of the tumor tissue, and reduce the amount of
agent that must be administered to effect the desired response.
[0562] Also contemplated in the present invention is the use of
combination therapy to treat cancer, as described above.
[0563] In a preferred embodiment, immunization is done to promote a
tumor-specific T cell immune response. In this embodiment, a
bioactive agent that inhibits BTLA activation is administered in
combination with a tumor-associated antigen other than B7x. The
combination of a tumor-associated antigen and a BTLA-inhibitory/B7x
functional-mimetic promotes a tumor specific T cell response, in
which T cells encounter a lower level of inhibition than exerted by
the tumor tissue in the absence of the bioactive agent.
[0564] In one aspect, the present invention provides a medicament
for the treatment of cancer.
Promote Graft Survival
[0565] The present invention also provides compositions and methods
for modulating normal but undesired immune responses involving T
and B cell activity. In a preferred embodiment, compositions and
methods for inhibiting the host lymphocyte response to transplanted
tissue and organs are provided. Desirably, these compositions and
methods may be used to prolong the survival of grafted tissue.
[0566] Preferred compositions for use in the prevention of acute
and/or chronic graft rejection comprise the agonists of
BTLA-mediated signaling described herein including, e.g., the
above-described mimicking agents. Especially preferred agents
include a BTLA-HVEM agonist as described above; function-activating
anti-BTLA antibodies; peptides that mimic HVEM (mimetics); peptides
that mimic B7x; B7x polypeptides comprising the B7x extracellular
domain, or a portion thereof; HVEM polypeptides comprising the HVEM
CDR domain, or a portion thereof; B7x-Ig fusion proteins comprising
the B7x extracellular domain, or a portion thereof; small molecule
chemical compositions that mimic the natural interaction of BTLA
and HVEM; and small molecule chemical compositions that mimic the
natural interaction of BTLA and B7x.
[0567] In addition to their utility in general immunosuppressive
strategies, the subject agonists of BTLA-mediated signaling
described herein may also have important implications for tolerance
induction in tissue and organ transplantation, by biasing the
recipient T helper cell immune response away from an unfavorable
Th-1-type response and towards a more favorable Th-2 type response.
As demonstrated herein, BTLA is highly expressed in Th-1 type T
cells in comparison with low expression in Th-2 type T cells after
T cell polarization, and thus the subject agonists will
preferentially attenuate the activity of Th-1 cells over Th-2
cells. Recent evidence suggests that the creation of a Th-2 type
cytokine milieu can be more favorable to tolerance induction, and
thus the need for life-long immunosuppressive therapy in transplant
patients may be reduced or eliminated by employing the compositions
and methods described herein.
[0568] In one aspect, the present invention provides a medicament
for use in transplantation and immune suppression. In one
embodiment, the medicament comprises a BTLA-HVEM agonist. In
another embodiment, the medicament comprises a BTLA-B7x agonist.
Also provided are methods for making such a medicament.
(VII) Administration of Therapeutic Compositions
[0569] The bioactive agents of the present invention are
administered to subjects in a biologically compatible form suitable
for pharmaceutical administration in vivo. By "biologically
compatible form suitable for administration in vivo" is meant a
form of the agent to be administered in which any toxic effects are
outweighed by the therapeutic effects of the antibody. The term
subject is intended to include living organisms in which an immune
response can be elicited, e.g., mammals. Examples of subjects
include humans, dogs, cats, mice, rats, and transgenic species
thereof. Administration of a bioactive agent as described herein
can be in any pharmacological form, including a therapeutically
active amount of an anti-B7x or anti-BTLA antibody alone or in
combination with each other, or with an additional therapeutic
agent as described herein and a pharmaceutically acceptable
carrier. Administration of a therapeutically effective amount of
the therapeutic compositions of the present invention is defined as
an amount effective, at dosages and for periods of time necessary
to achieve the desired immunotherapeutic result. For example, a
therapeutically active amount of an anti-B7x or anti-BTLA antibody
may vary according to factors such as the disease state, age, sex,
and weight of the individual, and the ability of peptide to elicit
a desired response in the individual. A dosage regime may be
adjusted to provide the optimum therapeutic response. For example,
several divided doses may be administered daily or the dose may be
proportionally reduced as indicated by the exigencies of the
therapeutic situation.
[0570] The bioactive agent (e.g., antibody) may be administered in
a convenient manner such as by injection (subcutaneous,
intravenous, etc.), oral administration, inhalation, transdermal
application, or rectal administration. Depending on the route of
administration, the bioactive agent may be coated in a material to
protect the compound from the action of enzymes, acids and other
natural conditions which may inactivate the compound.
[0571] To administer a bioactive agent comprising a protein, e.g.
an anti-BTLA antibody, by other than parenteral administration, it
may be necessary to coat the peptide with, or co-administer the
antibody with, a material to prevent its inactivation. An anti-B7x
or anti-BTLA antibody may be administered to an individual in an
appropriate carrier, diluent or adjuvant, co-administered with
enzyme inhibitors or in an appropriate carrier such as liposomes.
Pharmaceutically acceptable diluents include saline and aqueous
buffer solutions. Adjuvant is used in its broadest sense and
includes any immune stimulating compound such as interferon.
Exemplary adjuvants include alum, resorcinols, non-ionic
surfactants such as polyoxyethylene oleyl ether and n-hexadecyl
polyethylene ether. Enzyme inhibitors include pancreatic trypsin
inhibitor, diisopropylfluorophosphate (DEP) and trasylol. Liposomes
include water-in-oil-in-water emulsions as well as conventional
liposomes (Strejan et al., (1984) J. Neuroimmunol 7:27).
[0572] The bioactive agent may also be administered parenterally or
intraperitoneally. Dispersions can also be prepared in glycerol,
liquid polyethylene glycols, and mixtures thereof and in oils.
Under ordinary conditions of storage and use, these preparations
may contain a preservative to prevent the growth of
microorganisms.
[0573] In one embodiment, a pharmaceutical composition suitable for
injectable use include sterile aqueous solutions (where water
soluble) or dispersions and sterile powders for the extemporaneous
preparation of sterile injectable solutions or dispersion. In all
cases, the composition will preferably be sterile and fluid to the
extent that easy syringability exists. It will preferably be stable
under the conditions of manufacture and storage and must be
preserved against the contaminating action of microorganisms such
as bacteria and fungi. The carrier can be a solvent or dispersion
medium containing, for example, water, ethanol, polyol (for
example, glycerol, propylene glycol, and liquid polyetheylene
glycol, and the like), and suitable mixtures thereof. The proper
fluidity can be maintained, for example, by the use of a coating
such as lecithin, by the maintenance of the required particle size
in the case of dispersion and by the use of surfactants. Prevention
of the action of microorganisms can be achieved by various
antibacterial and antifungal agents, for example, parabens,
chlorobutanol, phenol, asorbic acid, thimerosal, and the like. In
many cases, it will be preferable to include isotonic agents, for
example, sugars, polyalcohols such as manitol, sorbitol, sodium
chloride in the composition. Prolonged absorption of the injectable
compositions can be brought about by including in the composition
an agent which delays absorption, for example, aluminum
monostearate and gelatin.
[0574] Sterile injectable solutions can be prepared by
incorporating one or more bioactive agents, together or separately
with additional immune response stimulating agents or
immunosupressants, in the required amount in an appropriate solvent
with one or a combination of ingredients enumerated above, as
required, followed by filtered sterilization. Generally,
dispersions are prepared by incorporating the bioactive agent into
a sterile vehicle which contains a basic dispersion medium and the
required other ingredients from those enumerated above. In the case
of sterile powders for the preparation of sterile injectable
solutions, the preferred methods of preparation are vacuum drying
and freeze-drying which yields a powder of the active ingredient
plus any additional desired ingredient from a previously
sterile-filtered solution thereof.
[0575] When a bioactive agent comprising a peptide is suitably
protected, as described above, the protein may be orally
administered, for example, with an inert diluent or an assimilable
edible carrier. As used herein "pharmaceutically acceptable
carrier" includes any and all solvents, dispersion media, coatings,
antibacterial and antifungal agents, isotonic and absorption
delaying agents, and the like. The use of such media and agents for
pharmaceutically active substances is well known in the art. Except
insofar as any conventional media or agent is incompatible with the
active compound, use thereof in the therapeutic compositions is
contemplated. Supplementary bioactive agents can also be
incorporated into the compositions.
[0576] It is especially advantageous to formulate parenteral
compositions in dosage unit form for ease of administration and
uniformity of dosage. Dosage unit form as used herein refers to
physically discrete units suited as unitary dosages for the
mammalian subjects to be treated; each unit containing a
predetermined quantity of bioactive agent calculated to produce the
desired therapeutic effect in association with the required
pharmaceutical carrier. The specification for the dosage unit forms
of the invention are dictated by and directly dependent on (a) the
unique characteristics of the bioactive agent(s) and the particular
therapeutic effect to be achieved, and (b) the limitations inherent
in the art of compounding such an agent for the treatment of
sensitivity in individuals.
[0577] The specific dose can be readily calculated by one of
ordinary skill in the art, e.g., according to the approximate body
weight or body surface area of the patient or the volume of body
space to be occupied. The dose will also be calculated dependent
upon the particular route of administration selected. Further
refinement of the calculations necessary to determine the
appropriate dosage for treatment is routinely made by those of
ordinary skill in the art. Such calculations can be made without
undue experimentation by one skilled in the art in light of the
activity disclosed herein in assay preparations of target cells.
Exact dosages are determined in conjunction with standard
dose-response studies. It will be understood that the amount of the
composition actually administered will be determined by a
practitioner, in the light of the relevant circumstances including
the condition or conditions to be treated, the choice of
composition to be administered, the age, weight, and response of
the individual patient, the severity of the patient's symptoms, and
the chosen route of administration.
[0578] The toxicity and therapeutic efficacy of the bioactive
agents described herein can be determined by standard
pharmaceutical procedures in cell cultures or experimental animals,
e.g., for determining the LD50 (the dose lethal to 50% of the
population) and the ED50 (the dose therapeutically effective in 50%
of the population). The dose ratio between toxic and therapeutic
effects is the therapeutic index and it can be expressed as the
ratio LD50/ED50. Compounds which exhibit large therapeutic indices
are preferred. While compounds that exhibit toxic side effects may
be used, care should be taken to design a delivery system that
targets such compounds to the site of affected tissue in order to
minimize potential damage to uninfected cells and, thereby, reduce
side effects.
[0579] The data obtained from the cell culture assays and animal
studies can be used in formulating a range of dosage for use in
humans. The dosage of such agents lies preferably within a range of
circulating concentrations that include the ED50 with little or no
toxicity. The dosage may vary within this range depending upon the
dosage form employed and the route of administration utilized. For
any agent used in the method of the invention, the therapeutically
effective dose can be estimated initially from cell culture assays.
A dose may be formulated in animal models to achieve a circulating
plasma concentration range that includes the IC50 (i.e., the
concentration of the test agent which achieves a half-maximal
inhibition of symptoms) as determined in cell culture. Such
information can be used to more accurately determine useful doses
in humans. Levels in plasma may be measured, for example, by high
performance liquid chromatography.
[0580] In one embodiment of the present invention a therapeutically
effective amount of an antibody to HVEM, B7x or BTLA is
administered to a subject. As defined herein, a therapeutically
effective amount of antibody (i.e., an effective dosage) ranges
from about 0.001 to 50 mg/kg body weight, preferably about 0.01 to
40 mg/kg body weight, more preferably about 0.1 to 30 mg/kg body
weight, about 1 to 25 mg/kg, 2 to 20 mg/kg, 5 to 15 mg/kg, or 7 to
10 mg/kg body weight. The optimal dose of the antibody given may
even vary in the same patient depending upon the time at which it
is administered.
[0581] The skilled artisan will appreciate that certain factors may
influence the dosage required to effectively treat a subject,
including but not limited to the severity of the disease or
disorder, previous treatments, the general health and/or age of the
subject, and other diseases present. Moreover, treatment of a
subject with a therapeutically effective amount of an antibody can
include a single treatment or, preferably, can include a series of
treatments. In a preferred example, a subject is treated with
antibody in the range of between about 0.1 to 20 mg/kg body weight,
one time per week for between about 1 to 10 weeks, preferably
between 2 to 8 weeks, more preferably between about 3 to 7 weeks,
and even more preferably for about 4, 5, or 6 weeks. It will also
be appreciated that the effective dosage of antibody used for
treatment may increase or decrease over the course of a particular
treatment. Changes in dosage may result from the results of assays
designed to monitor transplant status (e.g., whether rejection or
an immune response in the subject has occurred) as known in the art
or as described herein.
[0582] In one embodiment, a pharmaceutical composition for
injection could be made up to contain 1 ml sterile buffered water,
and 1 to 50 mg of antibody. A typical composition for intravenous
infusion could be made up to contain 250 ml of sterile Ringer's
solution, and 150 mg of antibody. Actual methods for preparing
parenterally administrable compositions will be known or apparent
to those skilled in the art and are described in more detail in,
for example, Remington's Pharmaceutical Science, 15th ed., Mack
Publishing Company, Easton, Pa. (1980), which is incorporated
herein by reference. The compositions comprising the present
antibodies can be administered for prophylactic and/or therapeutic
treatments. In therapeutic application, compositions can be
administered to a patient already suffering from a disease, in an
amount sufficient to cure or at least partially arrest the disease
and its complications. An amount adequate to accomplish this is
defined as a "therapeutically effective dose." Amounts effective
for this use will depend upon the clinical situation and the
general state of the patient's own immune system. For example,
doses for preventing transplant rejection may be lower than those
given if the patient presents with clinical symptoms of rejection.
Single or multiple administrations of the compositions can be
carried out with dose levels and pattern being selected by the
treating physician. In any event, the pharmaceutical formulations
should provide a quantity of the bioactive agents described herein
sufficient to effectively treat the patient.
[0583] Dose administration can be repeated depending upon the
pharmacokinetic parameters of the dosage formulation and the route
of administration used. It is also provided that certain protocols
may allow for one or more agents describe herein to be administered
orally. Such formulations are preferably encapsulated and
formulated with suitable carriers in solid dosage forms. Some
examples of suitable carriers, excipients, and diluents include
lactose, dextrose, sucrose, sorbitol, mannitol, starches, gum
acacia, calcium phosphate, alginates, calcium silicate,
microcrystalline cellulose, olyvinylpyrrolidone, cellulose,
gelatin, syrup, methyl cellulose, methyl- and
propylhydroxybenzoates, talc, magnesium, stearate, water, mineral
oil, and the like. The formulations can additionally include
lubricating agents, wetting agents, emulsifying and suspending
agents, preserving agents, sweetening agents or flavoring agents.
The compositions may be formulated so as to provide rapid,
sustained, or delayed release of the active ingredients after
administration to the patient by employing procedures well known in
the art. The formulations can also contain substances that diminish
proteolytic degradation and/or substances which promote absorption
such as, for example, surface active agents.
[0584] The pharmaceutical compositions can be included in a
container, pack, or dispenser together with instructions for
administration. Kits for practice of the instant invention are also
provided. For example, such a kit comprises a bioactive agent such
as, e.g., an antibody reactive with HVEM, B7x or BTLA, together
with a means for administering the antibody conjugate, e.g., one or
more syringes. The kit can come packaged with instructions for
use.
DEFINITIONS
[0585] By "BTLA signaling", "BTLA-mediated signaling",
`BTLA-mediated negative signaling" and variations thereof is meant
intracellular signaling in lymphocytes caused by the binding and/or
activation of the BTLA receptor by its corresponding ligand(s)
resulting in attenuation and/or down-regulation of lymphocyte
activity. In one aspect, BTLA-mediated signaling comprises
activation of SHP-1 and/or SHP-2.
[0586] "Lymphocyte activity" as used herein refers to the
immunological processes of B and T cell activation, proliferation,
differentiation and survival, as well as associated effector immune
functions in lymphocytic cells including cytolytic activity (Tc
cells), cytokine production (Th cells), antibody production (B
cells), and antigen presentation (B cells). As noted above, there
are numerous assays well known to the skilled artisan for detecting
and/or monitoring such processes, including but not limited to the
assays described in the examples provided herein.
[0587] As used herein, the phrase "interaction of BTLA and B7x"
refers to direct physical interaction (e.g. binding) and/or other
indirect interaction of a functional B7x molecule with a functional
BTLA receptor on a lymphocyte, resulting in stimulation of the BTLA
receptor and associated intracellular BTLA signaling. Similarly,
the phrase "natural interaction of BTLA and B7x" refers to direct
physical interaction (e.g. binding) and/or other indirect
interaction of a functional and endogenously expressed B7x molecule
with a functional and endogenously expressed BTLA receptor on a
lymphocyte, resulting in stimulation of the BTLA receptor and
associated intracellular BTLA signaling.
[0588] As used herein, "functional" means to be able to carry out
normal activities, such as to recognize and 40 bind a target, or to
activate intracellular signaling pathways upon stimulation.
[0589] As used herein, the term "blocking agent" includes those
agents that interfere with the interaction of B7x and BTLA, and/or
that interfere with the ability of B7x to inhibit lymphocyte
activity, e.g., as measured by cytokine production and/or
proliferation. The term "blocking agent" further includes agents
that inhibit the ability of BTLA to bind a natural ligand, e.g.,
B7x, and/or that interfere with the ability of BTLA to inhibit T
cell activity. Exemplary agents include function-blocking
antibodies, as well as peptides that block the binding of B7x with
BTLA but which fail to stimulate BTLA-mediated signaling in a
lymphocyte (e.g., BTLA fusion proteins), peptidomimetics, small
molecules, and the like. Preferred blocking agents include agents
capable of inhibiting the inducible association of BTLA with SHP-1
and/or SHP-2, or the signal transduction that derives from the
interaction of SHP-1 and/or SHP-2 with BTLA.
[0590] As used herein, the term "mimicking agent" includes those
agents that mimic the interaction of B7x and BTLA, and/or that
augment, enhance or increase the ability of B7x and/or BTLA to
inhibit lymphocyte activity. Exemplary agents include
function-activating antibodies, as well as peptides that augment or
enhance the ability of B7x to bind to BTLA or substitute for B7x in
stimulating BTLA-mediated signaling (e.g, B7x fusion proteins),
peptidomimetics, small molecules, and the like.
[0591] As used herein, the term "HVEM CRD1 domain" refers to the
CRD1 domain of an HVEM protein. An HVEM CRD1 domain binds to a BTLA
Ig domain, and can be specifically bound by a preferred HVEM
antibody disclosed herein. The HVEM CRD1 domain does not include
the CRD2 or CRD3 domains of the HVEM protein. A preferred CRD1
domain is that set forth by residues 41-76 of the human HVEM
protein sequence at Genbank accession no. AAB58354.1 (SEQ ID NO:
68). See Montgomery et al., Cell, 87:427-436, 1996. Other preferred
CRD1 domains are those having at least about 80%, 85%, 90% or 95%
identity to the sequence set forth by residues 41-76 of the human
HVEM protein sequence at Genbank accession no. AAB58354.1 (SEQ ID
NO: 68). Another preferred CRD1 domain is that set forth by
residues 39-80 of the murine HVEM protein sequence at Genbank
accession no. AAQ08183.1 (SEQ ID NO: 69). Other preferred CRD1
domains are those having at least about 80%, 85%, 90% or 95%
identity to the sequence set forth by residues 39-80 of the murine
HVEM protein sequence at Genbank accession no. AAQ08183.1 (SEQ ID
NO: 69).
[0592] As used herein, the term "HVEM CRD1 domain peptide" refers
to a peptide corresponding in sequence to a region of the CRD1
domain of HVEM, which peptide can bind to the Ig domain of BTLA. An
HVEM CRD1 domain peptide is capable of reducing the binding of the
HVEM CRD1 domain to the BTLA Ig domain, and is a BTLA-HVEM
antagonist.
[0593] As used herein, the term "BTLA Ig domain" refers to the
portion of a BTLA protein corresponding to the portion of BTLA that
has been used to identify the HVEM-BTLA interaction. In particular,
the BTLA Ig domain, as used herein, comprises an immunogloublin
domain. Further, as compared to the BTLA sequence of C57BL/6 mouse,
as found at Genbank accession no. NP 808252.1 (SEQ ID NO: 63), the
BTLA Ig domain corresponds to amino acids 30-166. Further, as
compared to the human BTLA sequence found at Genbank accession no.
AAP44003.1 (SEQ ID NO: 64), the BTLA Ig domain corresponds to amino
acids 31-149. A BTLA Ig domain binds to an HVEM CRD1 domain.
Further, a fragment of a BTLA Ig domain binds to an HVEM CRD1
domain, and can be specifically bound by a preferred BTLA antibody
disclosed herein. Some preferred BTLA Ig domains comprise a
cysteine residue corresponding to residue C85 of the murine BI/6
BTLA isoform (SEQ ID NO: 63), which corresponds to residue C79 of
the human BTLA isoform found at Genbank accession no. AAP44003.1
(SEQ ID NO: 64).
[0594] As used herein, the term "BTLA Ig domain peptide" refers to
a peptide corresponding in sequence to a region of the Ig domain of
BTLA, which peptide can bind to the CRD1 domain of HVEM and is
capable of reducing the binding of the BTLA Ig domain to the HVEM
CRD1 domain. Such peptides are BTLA-HVEM antagonists.
[0595] As used herein, the term "HVEM blocking antibody" refers to
an antibody that specifically binds to HVEM and reduces binding of
HVEM to BTLA. Preferred HVEM blocking antibodies bind to the CRD1
domain, more preferably to a segment thereof that binds to the Ig
domain of BTLA.
[0596] As used herein, the term "BTLA blocking antibody" refers to
an antibody that specifically binds to BTLA and reduces binding
BTLA to HVEM. Preferred BTLA blocking antibodies bind to the Ig
domain of BTLA, preferably to a segment thereof that binds to the
HVEM CRD1 domain.
[0597] As used herein, the term "BTLA-HVEM antagonist" refers to a
bioactive agent capable of reducing BTLA activity in a cell having
BTLA on its surface. Preferred BTLA-HVEM antagonists are capable of
reducing the binding of HVEM on the surface of a cell to BTLA on
the surface of the same or a second cell. In some preferred
embodiments, BTLA-HVEM antagonists are capable of binding to the
BTLA Ig domain. Binding of a BTLA-HVEM antagonist to BTLA on the
surface of a cell does not increase BTLA activity in the cell.
[0598] As used herein, the term "BTLA-HVEM agonist" refers to a
bioactive agent capable of increasing BTLA activity in a cell
having BTLA on its surface, thereby mimicking the action of HVEM on
BTLA. Preferred BTLA-HVEM agonists are capable of reducing the
binding of HVEM on the surface of a cell to BTLA on the surface of
the same or a second cell.
[0599] Both HVEM and BTLA are synthesized and inserted into the
plasma membrane as transmembrane proteins, and thereby expose
respective extracellular domains. The phrase "on the surface of a
cell" in respect of BTLA or HVEM refers to non-soluble BTLA and
HVEM protein localized at the plasma membrane.
[0600] As used herein, the term "antagonistic HVEM antibody" refers
to an antibody that specifically binds to HVEM and can reduce the
ability of HVEM to increase BTLA activity in a cell having BTLA on
its surface.
[0601] As used herein, the term "antagonistic BTLA antibody" refers
to an antibody that specifically binds to BTLA and can reduce the
ability of HVEM to increase BTLA activity in a cell having BTLA on
its surface. Binding of an antagonistic BTLA antibody to BTLA on
the surface of a cell does not increase BTLA activity in the
cell.
[0602] As used herein, the term "agonistic BTLA antibody` refers to
an antibody that specifically binds to BTLA, is capable of reducing
the binding of HVEM to BTLA, and increases BTLA activity in a cell
having BTLA on its surface.
[0603] By "BTLA activity" and variations thereof is meant
intracellular signaling and the effects thereof, caused by the
binding of BTLA on the surface of a cell by a BTLA agonist, e.g.,
HVEM on the surface of a second cell; CMV UL144. BTLA activity
includes but is not limited to inhibition of lymphocyte activation;
phosphorylation of BTLA intracellular domain tyrosine residues,
particularly those in the Grb2 binding site, the immunoreceptor
tyrosine-based inhibitory motif (ITIM), and/or the immunoreceptor
tyrosine-based switch motif (ITSM); binding of BTLA to SHP-1 and/or
SHP-2; activation of SHP-1 and/or SHP-2; binding of BTLA to Grb2;
and binding of BTLA to p85 of PI3K.
[0604] By "modulating BTLA activity" is meant increasing or
decreasing BTLA activity, which includes completely decreasing BTLA
activity such that no BTLA activity is detectable.
[0605] As used herein, the term "lymphocyte activation" refers to
the processes attendant B cell and T cell activation in primary or
subsequent immune responses, which processes include but are not
limited to cell proliferation, differentiation, migration, and
survival, as well as effector activities exhibited by B cells and T
cells such as, but not limited to, cytokine production, antibody
production, Fas ligand production, chemokine production, granzyme
production and release, and antigen presentation. Accordingly, as
used herein, modulation of lymphocyte activation includes
modulation of effector function, such as modulation of the
termination of effector function, etc. Numerous assays are well
known to the skilled artisan for detecting and/or monitoring such
processes.
[0606] As used herein, the term "immune response" includes both T
and/or B cell responses, i.e., cellular and/or humoral immune
responses. In one embodiment, the compositions and methods
disclosed herein can be used to reduce or enhance helper T cell
(Th) responses, and more preferably, Th1 cell responses. In another
embodiment, the compositions and methods disclosed herein can be
used to reduce or, enhance cytotoxic T cell (Tc) responses. The
claimed methods can be used to reduce or enhance both primary and
secondary immune responses and effector function (e.g., cytolytic
activity, cytokine and antibody production, and antigen
presentation). The immune response of a subject can be readily
determined by the skilled artisan using methods well known in the
art, for example, by assaying for antibody production, immune cell
proliferation, the release of cytokines, the expression of cell
surface markers, cytotoxicity, etc.
[0607] By "modulating lymphocyte activation" is meant increasing or
decreasing lymphocyte activation, which includes decreasing
lymphocyte activation such that no lymphocyte activation is
detectable.
[0608] Decreasing", "reducing", "inhibiting", and grammatical
equivalents thereof are used interchangeably herein and refer to
reductions in levels of binding, activity, etc., which include
reductions to levels beyond detection, including complete
inhibition. Reduced binding can be effected, for example, by
competitive binding of an antagonist.
[0609] As used herein, the term "immune response" includes T and/or
B cell responses, i.e., cellular and/or humoral immune
responses.
[0610] By "inhibiting tumor growth" is meant maintaining or
reducing the tumor burden of an animal having an extant tumor,
which includes eradicating the tumor. Even though the tumor burden
is maintained or reduced, cancer cell proliferation may be
ongoing.
[0611] As used herein, "human antibodies" includes humanized
antibodies.
[0612] It will be evident herein that the use of "BTLA", "B7x", and
"HVEM" refers to BTLA protein, B7x protein, and HVEM protein in
many instances.
EXAMPLES
[0613] The following examples are included to demonstrate preferred
embodiments of the invention. It should be appreciated by those of
skill in the art that the techniques disclosed in the examples that
follow represent techniques discovered by the inventors to function
well in the practice of the invention, and thus can be considered
to constitute preferred modes for its practice. However, those of
skill in the art should, in light of the present disclosure,
appreciate that many changes can be made in the specific
embodiments which are disclosed and still obtain a like or similar
result without departing from the spirit and scope of the
invention.
Methods for Examples 1-3
[0614] Mice and cells. Female BALB/c mice were purchased from
Jackson Laboratories (Bar Harbor, Me.) and were used at ages
6-9-weeks-old. Animals were housed in accordance with the Animal
Care and Use Committee regulations at the University of California,
Berkeley. All cell purifications were performed with magnetic cell
sorting separation columns (Milternyi Biotec, Auburn, Calif.) with
purities >95%. Macrophages were obtained from peritoneal cavity.
All cells were cultured in DMEM supplemented with 10% fetal calf
serum, 2 .mu.M L-glutamine, and 100 U/ml penicillin and
streptomycin (all from BioWhittaker), and 2 .mu.M 2-mercaptoethanol
(Sigma).
[0615] Production of fusion protein. B7xIg was prepared by fusing
the coding region of the extracellular domain of B7x to a chimeric
sequence containing the CH2-CH3 domain of mouse IgG1 and a
Myc-His-tag in pcDNA4 (a gift from Dr. William Sha, UC Berkeley).
The construct was linearized with BgIII and transfected into 293T
cells with FuGENE 6 Transfection Reagent (Roche, Ind.). Stable
transfectants were selected in 1 mg/ml of Zeocin (Invitrogen). To
produce fusion protein, stable transfectants were cultured in
serum-free DMEM for 72 h, the supernatant was collected and B7xIg
was purified by affinity column chromatography over His-Bind resin
(Novagen). The purity of the fusion protein was confirmed by
SDS-PAGE and by immunoblotting with antibodies against Myc and
mouse IgG.
[0616] Northern blot analysis. Mouse and human multiple tissue
northern blots (Clontech) were probed with cDNA fragments labeled
by .sup.32p-dCTP with Random Primed DNA Labeling kit (Roche). Mouse
and human B7x probes consisted of the entire coding regions.
.beta.-actin probes were supplied by Clontech. Blots were
hybridized for 1 h at 68.degree. C., washed twice at room
temperature in 2.times.SSC containing 0.05% SDS, followed by
0.1.times.SSC containing 0.1% SDS at 50.degree. C. and examined on
an PhosphorImager.
[0617] RT-PCR, and retrovirus constructs. Total RNA was isolated
using TR1Reagent (Sigma). Reverse transcription was performed using
oligo(dT) as the first primer and 2 .mu.g of total RNA with
Omniscript Reverse Transcriptase Kit (QIAGEN). RT-PCR was performed
using HotStarTag (QIAGEN). B7x-GFP fusion protein constructs were
generated using PCR to amplify the coding sequence of B7x without
the stop codon and then cloned into the pEGFPN3 vector (Clontech).
Following confirmation by DNA sequencing, the constructs of B7x-GFP
fusion protein or GFP alone were cloned into a mouse stem cell
virus (MSCV) retroviral expression vector (a generous gift from Dr.
William Sha, UC Berkeley). Retrovirus was produced by transient
transfection of the Pheonix-GP packaging cell line. For infection
of CHO cells, retroviruses were pseudotyped with vesicular
stomatitis virus G-glycoprotein. Stable clones were selected by
flow cytometric single cell sorting. For experiments using B7.2
only or B7.2/B7x cotransfected cells, the transfectants were
matched for B7.2 expression levels.
[0618] CHO cell stimulation of T cells. CHO cells transfected with
vector were incubated with mitomycin C (50 .mu.g/ml, Sigma) for 16
h. The cells were treated with PBS-EDTA (10 mM), washed twice,
resuspended in complete DMEM and left on ice for 2 h. The cells
were subsequently washed twice and resuspended in completed DMEM.
Purified T cells (10.sup.5/well) were incubated with
mitomycin-treated CHO transfectants (10.sup.5/well) in anti-CD3
(500A2)-bound-96-well plates. To analyze T cell proliferation,
cultures were pulsed with 1 .mu.Ci/well of [.sup.3H]thymidine for
the last 16 h of a 72-h incubation.
[0619] Cytokines ELISA. Aliquots of supernatants were collected at
48 h after initiation of cell cultures. IL-2, IL-4, IFN-.gamma. and
IL-10 were measured with monoclonal antibodies and recombinant
cytokine standards from PharMingen.
[0620] Flow cytometry. After incubation with the anti-Fc receptor
antibody 24G2 for Fc receptor-blocking, cells were stained with
B7x-Ig or mouse IgG1 as a control for 45 min on ice and then
stained with an anti-mouse-IgG PE-conjugate (Caltag) for 30 min. In
some experiments, cells were stained with PE-conjugated anti-ICOS
(eBioscience), anti-F480 (eBioscience), anti-CD4 and anti-CD8
(Caltag); or biotin-conjugate anti-B7.2 (Pharmingen), anti-CD28
(Pharmingen), anti-PD-1 (eBioscience), and then stained with
PE-Streptavidin (Caltag). The cells were analyzed on an XL (Coulter
Electronics, Hialeah, Fla.)
[0621] CSFE staining and analyses. Purified T cells (107/ml) were
washed with HBSS, labeled with 2.5 .mu.M CSFE (Molecular Probes,
OR) for 10 min at 37.degree. C., and then washed twice with cold
completed DMEM. T cells were stimulated with plate-bound anti-CD3
500A2 and the indicated CHO transfectants. On day 4 of culture,
cells were stained with PE-anti-CD4 or PE-anti-CD8, and analyzed by
flow cytometry.
Example 1
Expression of B7x
[0622] The expression of B7x mRNA in human and mouse tissues was
analyzed by Northern blot hybridization. Human B7x was present in a
single 3.2-kb mRNA readily detectable in kidney, liver, spleen and
placenta. Mouse B7x had three transcripts of 1.9, 3.5 and 8.2 kb,
and was expressed significantly in liver, testis, kidney, lung and
heart (FIG. 7). With RT-PCR, B7x mRNA was also detected in mouse
spleen, prostate, lymph node, thymus, eye, pancreas, B cells, T
cells, macrophages, and dendritic cells. (FIG. 8, and data not
shown).
[0623] Interestingly, 5 of 8 mouse B7x ESTs located in database
searches had been derived from mammary tumors, and 3 of 6 human B7x
ESTs originated from ovarian and uterine tumors. To determine
whether expression of B7x might be a regular feature of tumors, we
used Northern blot analysis to examine a panel of mouse tumors for
B7x mRNA expression. Most of the tumor cell lines tested, including
NB41A3 (neuroblastoma), P815 (mastocytoma), L1210 (lymphocytic
leukemia), R1.1 (T lymphoma), Hepa 1-6 (hepatoma), P19
(teratocarcinoma), M-MSV-BALB/3T3 (fibroblast transformed by
Moloney murine sarcoma virus), K-BALB (fibroblast transformed by
Kirsten murine sarcoma virus) and RAW264.7 (macrophage tumor)
expressed readily detectable B7x transcript (data not shown). In
addition, RT-PCR analysis of B7x mRNA expression revealed tha B7x
is expressed in a variety of tumor cells (FIG. 9).
[0624] To determine if T cells express a B7x counter receptor, we
performed flow cytometric analyses with a B7xIg fusion protein
prepared by linking the extracellular domain of B7x to the CH2-CH3
domains of mouse IgG1. Resting T cells did not bind B7x-Ig.
However, stimulation of T cells with PMA (50 ng/ml) and ionomycin
(1 .mu.g/ml) resulted in rapid acquisition of B7x binding on both
CD4 and CD8 T cells within 12 hours of stimulation (FIGS. 10 and
11). These results suggest that a receptor for B7x is rapidly
induced on both CD4 and CD8 T cells in response to stimulation.
[0625] Having determined that T cells express a counter-receptor
for B7x, we next examined the possibility that this receptor might
be one of the T cell surface molecules know to bind other B7 family
members. B7xlg failed to bind to transfected 293 cells expressing
high levels of CD28, CTLA-4, ICOS, or PD-1 (FIG. 12). Thus, B7x
binds to an activation-induced counter-receptor on T cells that is
distinct from the known CD28 family members.
Example 2
B7x Inhibits T cell Activation Processes
[0626] Initial experiments used purified T cells activated with
plate-bound anti-CD3 in the presence of different amounts of
immobilized B7xlg. B7xlg decreased proliferation and IL-2
production in a dose-dependent fashion. Additional experiments with
purified T cell subsets showed that B7xlg inhibited both CD4 and
CD8 T cell responses (FIG. 14). We next employed a conventional
costimulation assay. Purified T cells were activated with different
amounts of plate-bound anti-CD3 in the presence of CHO
transfectants expressing either GFP, B7.2 or B7x. As expected, T
cells stimulated in the presence of B7.2/CHO exhibited enhanced
proliferation and cytokine production compared to control GFP/CHO.
In contrast, B7x/CHO significantly reduced T cell proliferation and
cytokine production (FIG. 15). In order to determine the effect of
B7x on T cell activation in the face of costimulation, we also used
CHO cells which expressed B7.2 or coexpressed B7.2 and B7x. The
presence of B7x resulted in a partial inhibition of proliferation
and cytokine production by B7.2-costimulated T cells, an effect
that was more pronounced at lower levels of anti-CD3 (FIG. 16).
Together these results show that B7x can strongly inhibit
TCR-mediated T cell proliferation and cytokine production, even in
the presence of CD28-mediated costimulation.
Example 3
B7x Limits the Number and the Division Rate of T Cells that Enter
Cell Cycle
[0627] Having determined that B7x has a potential counter-receptor
on T cells and that the interaction of B7x with its receptor leads
to a dramatic inhibition of T cell activation, we further
investigated the mechanism of B7x action. T cells were labeled with
carboxyfluorescein diacetate succinimidyl ester (CSFE) and
stimulated with various CHO transfectants with or without
plate-bound anti-CD3. Cells were harvested on day 4 and stained for
CD4 and CD8 expression. B7x-mediated inhibition was determined by
electronically gating on CD4+ or CD8+ T cells populations and
measuring CFSE fluorescence intensity (FIGS. 17 and 18). T cells
did not divide when incubated with GFP/CHO only. When stimulated
with anti-CD3 and GFP/CHO, T cells went through at least 7-8
divisions, with most CD4+ and CD8+ T cells dividing more than 2
times. However, when T cells were incubated with anti-CD3 and
87.times./CHO, they were limited to 3-4 divisions. Further, only
about 1% of T cells did not divide when stimulated with anti-CD3,
whereas 31.4% of CD4+ and 34.3% of CD8+ T cells could not divide in
the presence of B7x. These differences in the number of divisions
as well as the percentage of non-dividing cells indicate that the
interaction of B7x and its receptor on T cells leads to decreased
proliferation by limiting the number and the division rate of both
CD4+ and CD8+ T cells that enter cell cycle.
Further Description of FIGS. 14-18
[0628] FIG. 14: T cells, and T cell subsets (CD4+ and CD8+) from
BALB/c mice were stimulated with plate-bound anti-CD3 (0.25 mg/ml
for CD4+ and total T cells; 2 ug/ml for CD8+ T cells) and
plate-bound B7x-Ig () or control Ig (.cndot.) (FIG. 14). IL-2
production and .sup.3H-thymidine incorporation were measured. The
results revealed that B7x inhibits TCR-mediated T cell responses,
particularly cytokine production and proliferation. Error bars in
FIG. 14 indicate standard deviation of triplicate cultures. The
data presented in FIG. 14 are representative of three independent
experiments.
[0629] FIG. 15: Purified T cells were stimulated with plate-bound
anti-CD3 and CHO transfectants expressing GFP (.cndot.), B7.2
(.smallcircle.) or B7x () (FIG. 15). Aliquots of supernatants were
collected at 48 h after initiation of cultures and cytokines
(IL-10, IL-4, IFN-.gamma., and IL-2) measured by ELISA, and cell
proliferation was measured after 72 h with [.sup.3H]thymidine
incorporation. The results reveal that B7x inhibits TCR-mediated T
cell responses, particularly cytokine production and proliferation.
The error bars in FIG. 15 indicate standard deviation of triplicate
cultures. The data in FIG. 15 are representative of five
independent experiments.
[0630] FIG. 16: T cells purified from BALC/c mice were stimulated
with plate-bound anti-CD3 and CHO transfectants expressing GFP
(.cndot.), B7.2 (.smallcircle.) or B7x/B7.2 (). The production of
IL-10, IL-4, IFN-.gamma., and IL-2, and the incorporation of and
3H-thymidine were measured (FIG. 16). Aliquots of supernatants were
collected at 48 h after initiation of cultures and cytokines
measured by ELISA. Proliferation was measured after 72 h with
[31-lithymidine incorporation. The error bars in FIG. 16 indicate
standard deviation of triplicate cultures. The data in FIG. 16 are
representative of three independent experiments.
[0631] FIG. 17: T cells were labeled with CSFE and stimulated with
or without plate-bound anti-CD3 (0.25 mg/ml) and CHO transfectants
expressing GFP or B7x. On day 4, cells were harvested, stained with
PE-anti-CD4 and analyzed by flow cytometry (FIG. 17). The results
reveal that B7x limits the number and division rate of T cells that
enter the cell cycle. Percentages in FIG. 17 refer to fraction of
cells in the non-dividing peak or divided more than 2 times. The
data in FIG. 17 are representative of three independent
experiments. These data show that B7x limits the number and
division rate of CD4+ T cells that enter the cell cycle.
[0632] FIG. 18: T cells were labeled with CSFE and stimulated with
or without plate-bound anti-CD3 (0.25 mg/ml) and CHO transfectants
expressing GFP or B7x. On day 4, cells were harvested, stained with
PE-anti-CD8 and analyzed by flow cytometry. Percentages refer to
fraction of cells in the non-dividing peak or divided more than 2
times. These data are representative of three independent
experiments. These data show that B7x limits the number and
division rate of CD8+ T cells that enter the cell cycle.
General Materials and Methods for Examples 4-9
[0633] Plasmid constructions. Myc-tagged BTLA constructs were
prepared as follows. The open reading frame of mBTLAs was amplified
from a colony obtained from screening a DO11.10 TH1 cDNA library
with primers J10-RV1-Bgl2 (5'-AGCTCTGAAGATCTCTAGGGAGGAAG-3') (SEQ
ID NO:28) and J10-Xho1 (5'.-CATGCTCGAGGAAGGICCAGACAGAGGTATTG-3'.)
(SEQ ID NO:29). The product was digested with Bg/II and XhoI and
cloned into the IRES-GFP-RV retrovirus48 at the BgIII and XhoI
sites to produce mBTLAs-RV. The N-terminal Myc-tagged version of
mBTLAs (Myc3-mBTLAs-RV) contains a triple Myc tag inserted
downstream of the signal peptide. To produce this construct, a PCR
product containing the mBTLA signal sequence and 3. overhang
homologous to the Myc tag was prepared with mBTLAs-RV as the
template and primers J10-RV1-Bg12 and J10-A2 (5.
GTTCAGATCCAAGGATGCTCCAGAGGCCC-3.) (SEQ ID NO:30). This PCR product
was annealed to a second PCR product comprising three copies of the
Myc epitope with 5. and 3. overhangs homologous to the N- and
C-terminal portions of BTLA, respectively, which had been amplified
from the triple Myc/Bluescript template with primers J10-A3 (5.
GAGCATCCTTGGATCTGAACAAAAGCTGATTA-3.) (SEQ ID NO:31) and J10-A4
(5.-CTTTCTCACAGAGCTCGTACAGGTCCTCT-3.) (SEQ ID NO:32). The triple
Myc/Bluescript template contains `anchor` sequences 5. (GS) and 3.
(YEL) to the Myc3 coding sequence, which are included in the final
Myc-tagged mBTLA protein. We then amplified the two annealed pieces
with primers J10-RV1-Bg12 and J10-A4. This product was annealed to
a third PCR product containing a 5. Myc homologous tail and the
C-terminal portion of BTLA amplified from the template mBTLAs-RV
with primers J10-A5 (5.-GTACGAGCTCTGTGAGAAAGCTACTAAGAGG-3.) (SEQ ID
NO:33) and J10-Xho1, and the full-length chimeric cDNA was
amplified with primers J10-RV1-Bg12 and J10 Xho1. The resulting
product was digested with Bg/II and XhoI and ligated into the Bg/II
and XhoI sites of IRES-GFP-RV to yield Myc3-mBTLAs-RV.
[0634] To produce the N-terminal Myc-tagged version of mBTLA
(Myc3-mBTLARV), primers J10-RV1-Bg12 and J10-A4 were used to
amplify the signal sequence linked to the triple Myc epitope from
template Myc3-mBTLAs-RV. A second PCR product was amplified with
primers J10-A5 and J10 Xho1 and the template mJ11W1. The two PCR
products were annealed and amplified with primers J10-RV1-Bg12 and
J10 Xho1, digested, and ligated into the retroviral vector to
produce Myc3-mBTLA-RV. A further modification was made by using the
Quick Change mutagenesis kit (Stratagene) to convert a cysteine
downstream of the Myc tag to alanine to mimic more accurately the
predicted signal sequence processing in which this cysteine would
be removed (SignalP V2.0). cyt-Myc3-mBTLA-RV was generated using
Quick Change mutagenesis of Myc3-mBTLA-RV with the primers mJ11
trunc top (5. TGATATTCCATAAAC CTGCCACTGAGCCAG-3.) (SEQ ID NO:34)
and mJ11 trunc bottom (5.-TGGCAGGTTTATG GAATATCAACCAGGTTAGTG-3.)
(SEQ ID NO:35). mBTLA-Myc2-RV, which expresses mBTLA with two
C-terminal Myc epitopes, was generated by `splicing by overlap
extension` (SOEing) together two PCR products (generated from
primers J10-RV1-Bg12 and 3. mj11 Myc tail (5.-GCTTTTGTTCACTTCTCACA
CAAATGGATGC-3.) (SEQ ID NO:36) with template mJ11W1, and primers 5.
mj11 Myc tail (5. TGAGGAGTGAACAAAAGCTGATTAGCGAAG-3.) (SEQ ID NO:37)
and new 3. Xho Myc tail (5.-CCGCTCGAGCTCCTACAGGTCCTCTTC-3.) (SEQ ID
NO:38) with template triple Myc/Bluescript) with primers
J10-RV1-Bg12 and new 3. XhoI Myc tail and Pfu polymerase. After
digestion with BgIII and XhoI, the PCR product was ligated into the
retroviral expression vector Tb-lym-GFP RV49, which had been
digested with Bg111 and XhoI, to generate mBTLA-Myc2-RV.
[0635] The N-terminal Myc-tagged version of hBTLA containing a
triple Myc tag inserted downstream of the signal peptide
(Myc3-hBTLA-RV) was prepared similarly. Three separate PCR products
were generated using the following primers and templates: 5. Bg12
hj11 (5'-GAAGATCTGCAGGAAATGAAGACATTGCCT-3'.) (SEQ ID NO:39) and 3.
Myc/hj11 bottom (5' TCAGCTTTTGTTCCCCATGGATGTTCCAGATGTCC-3') (SEQ ID
NO:40) with hj11#14u; 5. hj11/Myc top
(5.-CATCCATGGGGAACAAAAGCTGATTAGCGAAGAG-3.) (SEQ ID NO:41) and 3.
hj11/Myc bottom (5.-CACATGATTCTTTCAGGTCCTCTTCGCTAATCAGC-3.) (SEQ ID
NO:42) with triple Myc/Bluescript; and 5. Myc/hj11 top
(5.-GAGGACCTGAAAGAATCATGTGATGTACAGCTTTA-3.) (SEQ ID NO:43) and 3.
Xho hj11 (5.-CCGCTCGAGTTGGAGTCAGAAACAGACTTAAC-3.) (SEQ ID NO:44)
with hj11#14u. These PCR products were sequentially annealed and
amplified, and cloned into tb-lym-GFP-RV, which had been digested
with BgIII and XhoI. hBTLA containing three carboxy-terminal Myc
epitopes (hBTLA-Myc3-RV) was generated by SOEing together two PCR
products (from primers 5. Bg12 hJ11 and 3. hJ11 Myc tail
(5.-TGAGGAGTGAACAAAAGCTGATTAGCGAAG-3.) (SEQ ID NO:45) with template
hJ11#14u, and primers 5. hj11 Myc tail
(5.-TGAGGAGTGAACAAAAGCTGATTAGCGAAG-3.) (SEQ ID NO:46) and new 3.
Xho Myc tail with template triple Myc/Bluescript) with primers 5.
Bg12 hJ11 and new 3. Xho Myc tail and Pfu polymerase. After
digestion with Bg/II and XhoI, the PCR product was ligated into
retroviral expression vector Tb-lym-GFP-RV49, which had been
digested with BgIII and XhoI, to generate hBTLA-Myc3-RV. Embyronic
stem cells (MC50) were a gift of R. Schreiber.
[0636] Tyrosine mutations. Single tyrosine-to-phenylalanine
mutations of hBTLAMyc3-RV were produced using Quick Change
mutagenesis and Pfu polymerase (Stratagene) with the following
oligonucleotide pairs: Y226F top2
(5.-GAAACTGGAATTTATGATAATGACCCTGACCTTTG-3.) (SEQ ID NO:47) and
Y226F bot (5.-GGGTCATTATCAAAAATTCCAGTTTCTGATAGCAG-3.) (SEQ ID
NO:48); Y257F top2 (5.-ACCAGGCATTGTTTATGCTTCCCTGAACCATTCTG-3.) (SEQ
ID NO:49) and Y257F bot (5. AGGGAAGCAAAAACAATGCCTGGTTTGT-3.) (SEQ
ID NO:50); Y282F top2 (5.-GCACCAACAGAATATGCATCCATATGTGTGAGG-3.)
(SEQ ID NO:51) and Y282F bot
(5.-ATATGGATGCAAATTCTGTTGGTGCTTCTTTTA-3.) (SEQ ID NO:52). We
produced double and triple tyrosine-to-phenylalanine mutations of
hBTLA-Myc3-RV by using the oligonucleotide pair Y257F top2 and
Y257F bot first with the Y226F-mutated hBTLA-Myc3-RV template to
produce Y226F/Y257F and then with the Y282F-mutated template to
produce Y257F/Y282F. The oligonucleotide pair Y282F top2 and Y282F
bot was used with the Y226F-mutated template to produce
Y226F/Y282F, and with the Y226F/Y257F-mutated template to produce
Y226F/Y257F/Y282F.
[0637] Cell culture and expression analysis. Activation of DO11.10
TCR transgenic T cells and retroviral infections, northern analysis
and immunoblotting were done as described. We prepared tissue and
cellular RNA with the RNeasy Midi kit (Qiagen). A 20 stock of
pervanadate was prepared 5 min before use by diluting 12.5 .mu.l of
1 M NaVO4 and 4 .mu.l of 30% H.sub.2O.sub.2 to 600 .mu.l in
distilled water. The Opteia Mouse IL-2 set (PharMingen) was used to
measure for IL-2 by enzyme-linked immunosorbent assay (ELISA).
[0638] Immunoblotting and analysis of N-linked glycosylation. To
analyze the glycosylation status cells (15.times.10.sup.6 per ml)
were lysed in Triton X-100 lysis buffer (25 mM HEPES (pH 7.5), 0.15
M NaCl, 1% Triton (v/v), 1 mM pervanadate, 1 .mu.g/ml of leupeptin,
1 .mu.g/ml of pepstatin, 1 .mu.g/ml of aprotinin and 1 mM phenyl
methylsulfonyl fluoride) for 30 min at 4.degree. C. and centrifuged
at 14,000 g for 10 min. Extracts from 15.times.10.sup.6 per ml
cells were immunoprecipitated with 1 .mu.g of monoclonal antibodies
to Myc (clone 9E10; Santa Cruz) and 20 .mu.l of a 1:1 slurry of
protein G-Sepharose (PGS) (Pharmacia). After being washed three
times in Triton lysis buffer, the pellets were boiled for 10 min in
10 .mu.l of PNGase denaturing buffer (NEB). After centrifugation to
remove PGS, eluted proteins were transferred to PCR tubes
containing 1 .mu.l of 10% Nonidet P-40 (NP-40) and 1 .mu.l of 10.
G7 buffer (NEB), divided into two 6-.mu.l aliquots, and treated
without or with 1 .mu.l of PNGase F (NEB) for 1 h at 37.degree. C.
We boiled samples with 6 .mu.l of 2. SDS-PAGE sample buffer and
resolved them on 10% polyacrylamide gels. The proteins were
transferred to nitrocellulose, blocked in 3% bovine serum albumin
(BSA) in TBS-T buffer, blotted with rabbit anti-Myc (Santa Cruz)
and horseradish peroxidase (HRP)-conjugated goat anti-rabbit IgG
(Jackson), and analyzed by enhanced chemiluminescence (ECL). To
analyze the phosphorylation status cells were treated with 1 mM
pervanadate for 2 min at 37.degree. C., placed on ice for 1 min,
lysed in an equal volume of 2.1% Triton X-100 lysis buffer for 30
min and centrifuged for 10 min at 8,000 g. Extracts from
15.times.10.sup.6 cells were immunoprecipitated using 1 .mu.g of
anti-Myc (clone 9E10) and PGS. Blots were first analyzed for
phosphotyrosine (pTyr) using HRP-conjugated (clone 4G10, Upstate
Biotechnology), and then stripped and reanalyzed using rabbit
anti-Myc and HRP-conjugated goat anti-rabbit IgG.
[0639] TCR crosslinking. To analyze the induction of tyrosine
phosphorylation and association with SHP-1 and SHP-2 on TCR
crosslinking, we infected DO11.10 hybridoma T cells with GFP-RV48
or Myc3-mBTLAs-RV and purified them by sorting. Cells were
incubated with 4 .mu.g/ml of hamster anti-CD3E (clone 145-2C11,
PharMingen) and 2 .mu.g/ml of anti-Myc for 30 min at 4.degree. C.,
and crosslinked with 100 .mu.g/ml of prewarmed goat anti-mouse IgG
(GaM; Caltag) for various times, as indicated. We used
fluorescence-activated cell sorting (FACS) to confirm the
cross-reactivity of goat anti-mouse IgG with hamster anti-CD3E. As
a positive control for phosphorylation, some cells were incubated
with 1 mM pervanadate for 2 min at 37.degree. C. Cells were lysed
in RIPA buffer, and 1 ml of lysates from 25.times.10.sup.6 cells
were immunoprecipitated with 2 .mu.g of anti-Myc (9E10). We used
the following antibodies to analyze the immunoprecipitates:
anti-pTyr (RC2OH, Transduction Laboratories), polyclonal rabbit
anti-Myc (A-14, Santa Cruz), rabbit anti-SHP-2 (C-18, Santa Cruz),
rabbit anti-SHP-1 antibody (C-19, Santa Cruz) and anti-Myc (9E10).
To measure the effect of crosslinking on IL-2 production, 3.104
DO11.10 cells expressing GFP-RV, Myc3-mBTLAs-RV or Myc3-mBTLA-RV
were stimulated with 1 .mu.g/ml of immobilized anti-CD3E in
combination with various concentrations of immobilized polyclonal
rabbit anti-Myc or 50 ng/ml of PMA plus 1 .mu.M ionomycin. Culture
supernatants of triplicate cultures were collected after 24 h, and
the IL-2 concentration was determined by ELISA.
[0640] FACS analysis. Human IgG1 and goat anti-human PE were gifts
of M. Cella (Washington Univ., St. Louis, Mo., USA). The construct
for the B7h-Ig fusion protein, a gift of W. Sha (Univ. California
Berkeley), and the cDNA encoding the fusion protein were inserted
into the GFP-RV retroviral vector, and the retrovirus was used to
infect J558 cells. We purified fusion protein from infected J558
supernatant with His-Bind resin (Novagen). B7.1-Ig, B7.2-Ig,
PD-L1-Ig and PD-L2-Ig fusion proteins (Fc portion; human IgG1
isotype) were obtained from R&D Systems. All analyses were done
on a FACSCalibur. To measure the surface expression of BTLA, Bjab
cells were infected with amphotrophic retrovirus prepared in
Phoenix A packaging cells to express empty vector, Myc3-mBTLA-RV,
.cyt-Myc3-mBTLA-RV and Myc3-mBTLAs-RV. Expression of the Myc
epitope on GFP-positive cells was assayed on a FACScalibur with
rabbit anti-Myc polyclonal serum (Santa Cruz) and PE-conjugated
goat F(ab.).sub.2 anti-rabbit IgG (Jackson Research
Laboratories).
[0641] Antibody responses. Eight-week-old littermate wild-type,
Btla+/. and Btla./. mice on a pure 129SvEv background (n=5) were
injected intraperitoneally with 100 .mu.g of NP17-KLH (Biosearch
Technologies) in alum (Pierce) on days 0 and 14. Sera was collected
on day 28, and the titers of anti-NP were determined by ELISA using
NP25-BSA (Biosearch Technologies) for antibody capture and the SBA
Clonotyping system/HRP kit for IgG subclass-specific ELISA
(Southern Biotech).
[0642] In vitro responses of BTLA-deficient lymphocytes. T and B
cells from wildtype or BTLA-deficient mice were purified by cell
sorting using fluorescein isothiocyanate (FITC)-conjugated anti-CD4
(Caltag), FITC-conjugated anti-CD8a (PharMingen) or phycoerythrin
(PE)-conjugated anti-B220 (PharMingen). Cells (5.times.10.sup.5 per
ml) were stimulated with various concentrations of plate-bound
anti-IgM (Affinipure F(ab.).sub.2 fragment goat anti-mouse IgM
115-006-075, Jackson ImmunoResearch), LPS (serotype 055:B5, Sigma),
concanavalin A or plate-bound anti-CD3e (PharMingen, 145-2C11).
Cell proliferation was measured after 48 h by pulsing with
[.sup.3H]thymidine for 16 h.
[0643] Production and interaction of B7x-1g. In the public
databases we identified a B7 homolog, B7x, that was conserved in
mouse (accession code XP.sub.--143450.2 and AAH32925.1), rat
(accession code XP.sub.--227553.1) and human (accession code
NP.sub.--078902.1) and was highly conserved in sequence. B7x-Ig was
prepared by fusing the coding region of the extracellular domain of
B7x to the CH2-CH3 domain of mouse IgG1 and a Myc-His tag in pcDNA4
(a gift of W. Sha, Univ. California Berkeley, Berkeley, Calif.,
USA). The construct was linearized with BgIII and transfected into
293T cells with FuGENE 6 (Roche). Stable transfectants were
selected in 1 mg/ml of Zeocin (Invitrogen). To obtain fusion
protein, we cultured stable transfectants in serum-free Dulbecco's
modified Eagle's medium for 72 h, collected the supernatant and
purified B7x-Ig by affinity column chromatography over His-Bind
resin (Novagen). The purity of the fusion protein was confirmed by
SOS-PAGE and by immunoblotting with antibodies against Myc and
mouse IgG. The following reagents were used to measure receptor and
B7 ligand interactions: anti-CD4-FITC (Caltag); human IgG1 antibody
(Sigma); biotinylated anti-Myc (Santa Cruz); streptavidin-PE
(PharMingen); B7.1-Ig, B7.2-Ig, PD-L1-Ig and PD-L2-Ig fusion
proteins (Fc portion; human IgG1 isotype; R&D Systems); goat
anti-human Fc.gamma. F(ab.)2PE (Jackson ImmunoResearch); and
anti-PD-1-PE (PharMingen).
Example 4
Identification of BTLA
[0644] In a previous Affymetrix screen, we identified an anonymous
Th1-specific EST. The full-length cDNA of this EST, cloned from a
murine cDNA library, predicts a protein with a signal sequence,
extracellular V-like Ig domain, transmembrane region and
intracellular domain of approximately 100 amino acids (FIG. 19). A
homology search identified a single human gene homologue, having a
similar domain structure (FIG. 19). Notably, three tyrosine
residues within the cytoplasmic domain are contained within three
sequence motifs that are conserved between mouse and human, the
first, a potential Grb2 interaction site, and the others, ITIM,
sequences (FIG. 19). In addition to BTLA, a minor alternatively
spliced transcript, BTLAs, was detected by RT-PCR in mouse tissue.
BTLAs lacks exon 2, and thus the Ig domain. Additionally, an
alternatively spliced human BTLA transcript lacking exon 3, and
thus the TM domain, and portions of the cytoplasmic and
extracellular domains, was detected.
Methods for Example 4
[0645] We used an EST (aa839766) expressed by Th1, but not Th2,
cells to screen a Th1 cDNA phage library made in the Lambda ZAP
vector (Stratagene) and isolated a partial clone, BTLAs, that
lacked an Ig domain. Full length BTLA cDNA, amplified from WEHI
cell RNA by RT-PCR with primers J10-3K (5'-TTTGGCCTAAGATGCTGCTA-3')
(SEQ ID NO: 53) and J10-7F (5'-CACAGATTGGGTACGACATG-3'.) (SEQ ID
NO: 54), was inserted into the GEM-T Easy Vector (Promega) to
produce mJ11W1. We obtained additional full-length. BTLA cDNA
isolates by screening a second mouse splenocyte cDNA library
(Stratagene) using the 5' region of mj11W1 as a probe. Coding
sequence and intron-exon boundaries were further determined by
sequencing 129SvEv strain bacterial artificial chromosome clones
containing the BTLA region (Genome Systems). Some Ig domain
sequence polymorphisms occur among mouse strains. Human BTLA cDNA,
amplified from Ramos B lymphoma RNA by RT-PCR with primers hJ10
(5'-TTTTCCATCACTGATATGTGCAGG-3') (SEQ ID NO: 55) and hJ10 AS
(5'-GGTCCCTGTTGGAGTCAGAAAC-3') (SEQ ID NO: 56) based on the Celera
human genome assembly, was inserted into the GEM-T Easy Vector to
produce hJ11#14u. The Celera database sequence predicted the human
BTLA amino acid sequence set forth in FIG. 19 (SEQ ID NO:6), which
differs from the BTLA sequence obtained from Ramos cells (SEQ ID
NO:8) at amino acid residue 138. This is likely due to
polymorphism, given the different human sources. The BTLA sequence
as found in Ramos cells (SEQ ID NOs:7 and 8) was used for
experiments disclosed herein.
Example 5
Expression of BTLA (FIG. 22)
[0646] BTLA is expressed strongly in spleen and lymph node tissues,
but very weakly or undetectably by several somatic tissues. It is
expressed by both splenic B and T cells, with slightly higher
levels in the former. Further, we confirmed BTLA is expressed
highly in Th1 cells and resting splenic B cells, but weakly in Th2
and Tc2 cells. The A20 B cell line, but not macrophages and LAK
cells, also showed BTLA expression. BTLA is expressed weakly on day
2 after primary T cell activation with no difference between Th1
and Th2 conditions. On day 7, BTLA expression is slightly higher in
Th1 than Th2 cells, and after a second 2 round of polarization,
BTLA expression was much stronger in Th1 than Th2 cells, and
slightly diminished in Stat1-/-, but not Stat4-/-, Th1 cells. Thus,
BTLA is lymphoid specific and becomes selectively expressed on Th1
cells after full polarization.
Methods for Example 5
Further Description of FIG. 22
[0647] Northern blot analysis of an organ blot probed with a
full-length BTLA or GAPDH cDNA probe against 10 mg of tissue or
cellular RNA prepared with RNeasy Midi kit (QIAGEN). Northern blot
analysis was also performed on blots containing total RNA from the
indicated cells. Tc1 and Tc2 cells were prepared from in vitro
polarized 2C21 TCR transgenic T cells, LAK cells by culturing
C57/B6 splenocytes with 1000 U/ml IL-2 for 9 days, and macrophages
BALB/c bone marrow derived with L-cell conditioned media and
confirmed as >95% Mac-1 positive. Splenic B and T cells were
purified to >98% purity by cell sorting.
Example 6
Characterization of BTLA (FIG. 23)
[0648] To test whether BTLA is a transmembrane protein, we
expressed three forms of myc-epitope tagged BTLA in the BJAB cell
line. Cell surface expression of wild type BTLA was detected as
predicted. Notably, deleting either the cytoplasmic or Ig domain
increased surface expression, suggesting roles for these domains in
controlling the level of surface expression, perhaps similar to
CTLA-4 surface regulation by its cytoplasmic domain.
[0649] Next we confirmed that BTLA is a glycoprotein. Peptide
N-glycosidase F treatment reduced the apparent molecular weight of
both human and murine BTLA, consistent with N-linked glycosylation
sites predicted present between the Ig domain and transmembrane
region. The apparent molecular weight of peptide N-glycosidase F
treated human and murine BTLA was still higher than predicted by
its core amino acid sequence, suggesting additional modifications
such as O-link glycosylation. Finally, pervanadate treatment
induced tyrosine phosphotyrosine of BTLA. Single phenylalanine
mutations of tyrosines 226, 257 or 282 left pervanadate-induced
BTLA phosphorylation intact, but the triple tyrosine mutation
blocked phosphorylation completely. The Y226FIY257 double mutations
severely reduced pervanadate-induced phosphorylation, suggesting
tyrosine 282 is either weakly phosphorylated or requires prior
phosphorylation at Y226 or Y257. In summary, BTLA is an Ig domain
transmembrane glycoprotein that is inducibly tyrosine
phosphorylated at conserved cytoplasmic ITIM like motifs.
Further Description of FIG. 23
[0650] (a) Transmembrane cell surface expression of BTLA. BJAB
cells infected with myc-tagged BTLA, .DELTA.cyt BTLA, BTLAs and
empty vector were stained with anti-myc mAb (9E10, Santa Cruz) and
visualized by phycoerythrin (PE)-conjugated goat anti-mouse IgG
(CALTAG). Cells were analyzed on a FACScalibur and gated for GFP+
cells.
[0651] (b) Murine and human BTLA contain N-linked oligosaccharides.
BJAB cells infected with mouse BTLA or human BTLA were lysed and
BTLA proteins were immunoprecipitated with anti-myc Ab (9E10, Santa
Cruz). The immunoprecipitates were treated with peptide
N-glycosidase F where indicated and analyzed by anti-myc Western
blotting.
[0652] (c) Tyrosine phosphorylation of BTLA upon pervanadate
stimulation. BJAB cells infected with WT or single tyrosine mutants
were incubated in the absence or presence of pervanadate for 2 min
at 37.degree. C. Cells were lysed and BTLA proteins were
immunoprecipitated with anti-myc Ab. The immunoprecipitates were
first analyzed using antipTyr (RC2OH) Western blotting (top).
Membrane was then stripped and incubated with rabbit anti-myc Ab
(bottom).
[0653] (d) BJAB cells infected with double or triple tyrosine
mutants were analyzed for tyrosine phosphorylation by pervanadate
treatment. Samples were prepared similarly as described above.
Example 7
Inducible Association of BTLA with SHP-2 (FIG. 24)
[0654] Sequences surrounding Y226 suggest potential Grb2
interaction, Y257 an ITIM motif, and Y282 are similar to the ITSM
motif in PD-113 and SLAM (CD150/IPO-3). To evaluate such potential
interactions, we developed a system of inducible BTLA
phosphorylation. An extracellular myc-tagged BTLAs was expressed
stably in the DO11.10 hybridoma. In similar strategy used for
crosslinking PD-1 with the BCR complex, we crosslinked BTLA with
the TCR using antibodies to CD3 and the myc epitope, followed by
secondary crosslinking. With this approach, we detected BTLA
tyrosine phosphorylation that was dependent upon secondary
crosslinking and not induced with only CD3 or anti-myc antibodies
alone and was specific to BTLA-transfected cell.
[0655] BTLA tyrosine phosphorylation was time dependent, appearing
rapidly and optimal at 2-3 minutes, and extinguished by 10 minutes
after secondary crosslinking. We surveyed various signaling
molecules for co-immunoprecipitation with myc-BTLA. Notably, we
found strong association with SHP-2 that occurred with the same
time course as BTLA phosphorylation that was dependent upon
co-crosslinking. Since SHP-2 association with BTLA was also induced
by pervanadate, this condition was used to further examine
SHP-2/BTLA association. Pervanadate treatment induced.
[0656] BTLA tyrosine phosphorylation, and SHP-2 was co-precipitated
only with phosphorylated BTLA. In anti-SHP-2 immunoprecipitations,
BTLA co-precipitates only in pervanadate treated cells, and not in
untreated cells.
[0657] Finally, we confirmed this inducible SHP-2 association
occurs for human BTLA. A myc-tagged human BTLA was expressed in the
human T cell line Jurkat. Immunoprecipitated myc-hBTLA
co-precipitated with SHP-2 only in pervanadate treated cells, and
was specific to myc-hBTLA expression. Likewise, immunoprecipitation
with anti-SHP-2 led to the coprecipitation of myc-BTLA only in
pervanadate treated cells. Under these conditions, we did not
detect specific co-immunoprecipitation of BTLA with Grb2, SHIP, or
SHP-1.
[0658] Crosslinking BTLA with TCR attenuated IL-2 production in a T
cell hybridoma. Myc-tagged BTLA and BTLAs was stably expressed in
DO11.10 hybridoma T cells. The control DO11.10 hybridoma infected
with GFP-RV showed anti-CD3-induced IL-2 production that was not
affected by plate-bound anti-myc antibody. In contrast, IL-2
production by myc-BTLA expressing DO11.10 cells showed inhibition
by plate-bound anti-myc antibody that was dose-dependent. No
differences in PMA/Ionomycin-induced IL-2 production were
observed.
Further Description of FIG. 24
[0659] (a) Tyrosine phosphorylation of BTLA upon TCR cross-linking.
DO11.10 hybridoma T cells were infected with the empty retroviral
vector (GFP-RV) or retrovirus expressing BTLAs containing an
extracellular myc Epitope (myc-BTLAs) and infected cells purified
by sorting. For crosslinking, cells were incubated (+) with 4 mg/ml
of anti-CD3.epsilon. (clone 145-2C11, PharMingen) (.alpha.CD3) or 2
mg/ml of anti-myc (clone 9E10, Santa Cruz) (amyc) as indicated for
30 min at 4.degree. C. After washing, cells were treated with 100
mg/ml of pre-warmed goat anti-mouse IgG antibody (CALTAG) (GaM) for
indicated time. As a positive control for phosphorylation, cells
were incubated with 1 mM pervanadate for 2 min at 37.degree. C.
Cells were lysed in RIPA buffer, and 1 ml lysates of
25.times.10.sup.6 cells were immunoprecipitated with 2 mg of
anti-myc antibody (9E10). Immunoprecipitates were analyzed first
with anti-phosphotyrosine (RC2OH, Transduction Laboratories) as
described (upper panel), membranes stripped and re-probed with
polyclonal rabbit anti-myc antibody (A-14, Santa Cruz) (middle
panel), and finally with rabbit anti-SHP-2 antibody (C-18, Santa
Cruz) (bottom panel). Arrowheads indicate the major glysosylated
forms of BTLAs.
[0660] (b) BTLA tyrosine phosphorylation requires co-crosslinking.
Cells described in (a) were treated (+) as described above, only
with .alpha.CD3 or amyc antibodies, as indicated, followed by
secondary GaM, and analyzed as in (a) for phosphotyrosine (pTyr)
(top panel) or Myc (bottom panel).
[0661] (c) Cells described in (a) were incubated in the absence (-)
or presence (+) of pervanadate for 2 min at 37.degree. C., lysed in
1% NP-40 lysis buffer and immunoprecipitated using anti-myc
antibody as in (a). Immunoprecipitates and whole cell lysates
(25.times.10.sup.6) were first analyzed using antiphosphotyrosine
(p-Tyr) (RC2OH) (middle panel), stripped and probed for SHP-2 (top
panel, and finally for Myc as in (a).
[0662] (d) Cells described in (a) were incubated in the absence (-)
or presence (+) of pervanadate for 2 min at 37.degree. C., lysed in
1% NP-40 lysis buffer and immunoprecipitated using anti-SHP-2, and
immunoprecipitates and whole cell lysates analyzed using anti-myc
antibody (upper panel) stripped and re-probed for SHP-2 (lower
panel).
[0663] (e) Jurkat T cells were infected with GFP-RV or with a
retrovirus expressing a full length human BTLA containing an
N-terminal myc epitope. Infected Jurkat T cells were sorted three
times to obtain a >95% population containing high surface
expression of myc-hBTLA. The indicated cells were treated (+) with
pervanadate for 4 min at 37.degree. C., lysed in 1% Triton lysis
buffer, immunoprecipitated with anti-myc (9E10) (left panel) or
anti-SHP-2 (Santa Cruz) (right panel), and immunoprecipitates
analyzed for myc, SHP-2 and phosphotyrosine as above.
[0664] (f-g) The 3.times.10.sup.4 DO11.10 expressing control vector
(GFP-RV), myc-BTLAs, or myc-BTLA were stimulated with 1 mg/ml
immobilized anti-CD3.epsilon. mAb in combination with the indicated
concentrations of immobilized anti-myc antibody (9E10) (f) or 50
ng/ml PMA plus 1 mM ionomycin (g). Culture supernatants of
triplicate cultures were collected at 24 hours and IL-2
concentration was determined by ELISA. In (f), IL-2 titer was
normalized by the IL-2 concentration induced by .alpha.CD3
stimulation alone.
Example 8
Generation and Analysis of BTLA-/- mice. (FIG. 25)
[0665] To test for an in vivo role as an inhibitory receptor, we
targeted the BTLA gene to produce BTLA-/- mice. 129SvEv background
BTLA-/- lacked BTLA mRNA expression in peripheral lymphocytes. No T
or B cell developmental defects in thymus or bone marrow in BTLA-/-
mice. We produced mixed 129/Balb/c background BTLA-/- DO11.10 TCR
transgenic mice for in vitro analysis of T cells. Fully polarized
BTLA-/- Th1 cells showed enhanced proliferative responses in
response to OVA-pulsed dendritic cells in vitro. Approximately
two-fold increased proliferative responses were observed to 0.3 mM
OVA peptide presented by CD8+ or CD8-CD11c+ dendritic cells. After
NP-KLH/alum immunization, we observed approximately three-fold
increase in NP-KLH specific IgG1, IgG2a and IgG2b isotypes in
BTLA-/- compared to control littermate 129/SvEv mice at 4 weeks.
These results suggest BTLA ligation during T cell activation might
attenuate the strength of Th1 responses.
Further Description of FIG. 25
[0666] (a) The figure shows the BTLA locus and targeting construct.
Exons III through VI, encoding extracellular, transmembrane and
cytoplasmic regions are indicated. BgIII digestion of the germline
locus generates a 14.2 kb restriction fragment hybridizes to probes
A and B, and 8.4 fragment in correctly targeted clones. B, BamHI;
Bg, BgIII; E, EcoRI; SaI, SaII; X, XbaI; Xh, XhoI. TK, thymidine
kinase gene; neo, neomycin resistance cassette.
[0667] (b) Southern analysis. BgIII-digested tail DNA hybridized
with probe B.
[0668] (c) Northern analysis. RNA was prepared directly from
splenocytes of mice of the indicated genotype, and Northern blots
hybridized to a full length mouse BTLA cDNA probe, stripped and
re-probed for GAPDH.
[0669] (d) Proliferative responses of polarized Th1 cells induced
by incubation with Ag-pulsed DCs. BTLA-/- mice were back-crossed
onto the DO11.10 TCR background. Naive CD4 T cells from DO11.10+
BTLA+/+ or BTLA-/- mice were activated in vitro passed biweekly in
Th1 conditions. Resting Th1 cells (5.times.10.sup.4) were incubated
with BALB/c derived CD8+ or CD8- DCs (2.5.times.104 (top) or
0.25.times.10.sup.4-(bottom) with or without 300 nM of OVA323-339
peptide. Cell proliferation was measured by pulsing with [.sup.3H]
thymidine for 16 hours.
Further Description of FIG. 29
[0670] (a) Thymus, spleen and bone marrow cells from 8 week old
BTLA+/+ and BTLA-/- littermates were stained using CD4-PE,
CD8-FITC, CD3.epsilon.-biotin/SA-Cychrome, B220-PE,
.alpha.IgM-biotin/SA-Cychrome, .alpha.lgD-FITC and CD43-FITC
(PharMingen). For splenocytes and bone marrow cells, 2.4G2
(antimouse CD16/32 Ab, PharMingen) was used to block non-specific
binding of staining antibodies to Fc receptors. The percentages of
the live cells in the quadrants or gates are indicated. (b)
Splenocytes were stained with .gamma..delta.-TCR-FITC, DX5-FITC
(pan NK), Gr-1-biotin/SA-Cychrome, Mac-1-biotin/SA Cychrome, and
anti-cKit-biotin/SA-Cychrome (PharMingen.) The histograms were
overlayed for each marker (black line; +/+, red line; -/-). (c)
Thymocytes and splenocytes from 8 weeks old BTLA+/+ and BTLA-/-
littermates were counted by trypan-blue dye exclusion. The data are
presented as the mean.+-.SD of five mice.
Example 9
B7x Binding to Lymphocytes Requires BTLA Expression (FIG. 13)
[0671] T cells purified from wildtype and BTLA -/- mice were
stained B7x-Ig fusion protein, which revealed that BTLA is required
for binding of B7x-Ig fusion protein to T cells, implicating BTLA
as a counter-receptor for B7x. Additionally, as shown in FIG. 31
(b) and (c), BTLA expression is not required for the binding of
B71.11 g, B7.21 g, PD-L11g, PD-L21g and B7hlg, to Th1 cells.
Example 10
In Vitro Responses of BTLA-Deficient Lymphocytes (FIG. 32)
[0672] T and B cell from wild-type (WT) or BTLA-deficient (KO) mice
were purified by cell sorting using anti-CD4-FITC,
anti-CD8.alpha.-FITC or anti-B220-PE. Cells were stimulated with
the indicated final concentrations of plate-bound anti-IgM, LPS,
concanavalin A or plate-bound anti-CD3. Cell proliferation was
measured by pulsing with [.sup.3H]thymidine for 16 h. These results
support that BMA has inhibitory effect on lymphocyte responses.
Example 11
Increased EAE Susceptibility in BTLA-/- Mice (FIG. 26)
[0673] To test for an in vivo action of BTLA in T cells, we
considered experimental allergic encephalitis (EAE). Our data
suggest BTLA may be inhibitory, so we required a system that could
potentially reveal enhanced T cell responses in BTLA-/- mice. Since
presently we have pure 129 background BTLA-/- mice, we determined
the antigen dose-titration of the MOG peptide in this background.
10 .mu.g and 50 .mu.g of peptide induced severe disease in 129SvEv
mice, but 2 .mu.g induced disease, which was more mild and delayed.
At this antigen dose, BTLA-/- mice showed higher incidence,
increased clinical score, earlier disease onset and prolonged
duration compared to littermate wild type controls. Histologocial
analysis supported these results (data not shown), demonstrating
infiltration of the CNS in MOG-induced EAE in BTLA-deficient
mice.
Further Description of FIG. 26
[0674] (a) Titration of MOG peptide in 129 SvEv mice. 129 SvEv mice
were injected subcutaneously with MOG peptide at 2 .mu.g, 10 .mu.g,
and 50 .mu.g (n=5) in IFA and 500 .mu.g of mycobacterium on day
0.300 ng of Pertussis toxin was injected intravenously on day 1 and
3. C57BL/6 mice were injected with 10 .mu.g of MOG used as positive
controls. Mice were monitored daily for clinical symptoms. Clinical
scores: score 0, normal mouse, no overt signs of disease; 1, limp
tail or hind limb weakness, but not both; 2, limp tail or hind limb
weakness; 3, partial hind limb paralysis; 4, complete hind limb
paralysis; 5, moribund state, death by EAE, sacrifice for humane
reasons)
[0675] (b) Active induction of EAE by suboptimal dose of MOG
peptide in BTLA-/- mice. 6-8 weeks old pure 129 SvEv BTLA-/- or
wild type littermate control mice (n=5) were injected with 2 .mu.g
of MOG peptide as described in (a). Mean clinical scores: Wt,
0.6.+-.0.9; BTLA-/-, 2.4.+-.1.7. Mean peak clinical score; Wt,
1.5.+-.0.7; BTLA-/-3.0.+-.1.2.
[0676] For further discussion, see Watanabe N, et al., BTLA is a
lymphocyte inhibitory receptor with similarities to CTLA-4 and
PD-1. Published online: 8 Jun. 2003, doi:10.1038/ni944 Nat.
Immunol. 2003 Jun. 8 [Epub ahead of print] PMID: 12796776, which is
expressly incorporated herein by reference.
Example 12
Experimental BTLA Antibodies
[0677] Armenian hamsters and Balb/c BTLA KO mice were immunized
with oxidatively refolded BI/6 BTLA tetramer protein. The ability
of antibody to block binding of BTLA tetramer to HVEM was
determined.
TABLE-US-00002 Allelic Clone Isotype Specificity Blocking?
Applications 6A6 Hamster IoG BI/6 only Yes FACS, IP 6F7 Mouse IgG1,
Balb/c and 81/6 Yes FACS, IP, WB 6G3 Mouse IgG1, Balb/c and BI/6
Yes FACS, IF 6H6 Mouse IgG1, Balb/c and BI/6 Weak FACS, IP 8F4
Mouse IgG1, Balb/c and BI/6 Yes FAGS, IP 3F9.D12 Mouse IgG1, Balb/c
and BI/6 Yes FACS, IP 3F9.C6 Mouse IgG1, BI/6 only No FAGS, IF,
WB
[0678] Yeast Display Data: The ability of antibody to bind to BTLA
mutants was determined.+indicates binding.
TABLE-US-00003 BI/6 BTLA Mutations 6A6 3F9.C6 6G3 6F7 3F9.D12 P41E
+ + + + + T45N + + + + + P41 E, T47K + + + + + P41 E, Q52H + + + +
+ P41 E, R55W + - + + + P41 E, Q63E - + + + + P41 E, C85W +/- + +/-
+/- +/- P41 E, S91G + + + + + P41E, Q102R - + + + + P41 E, T143R +
+ + + + WEHI.2 - - - - -
Example 13
BTLA Ligand Binding and BTLA Activation
[0679] B7 molecules bind to MYPPPY motif on CD28 and CTLA4 within
FG loop. For example, PD-L1 and PD-L2 bind to FG loop of PD-1. The
FG loop of BTLA is four amino acids shorter than FG loop in
CD28/CTLA4, and epitope mapping places HVEM interaction towards
`DEBA` face of 1g fold.
BTLA Binds Naive T Cells but does not Bind B7x
[0680] To test for direct interactions between BTLA and B7x, we
made NI H 3T3 cell lines stably expressing the extracellular
domains of B7x, BTLA, and programmed death 1 (PD-1) and its ligand
(PD-L1), and stained the cells with PD-1 and BTLA tetramers and
with PD-L1 and B7x Fc fusion proteins. Whereas PD-1 tetramer bound
to cells expressing PD-L1, as expected, the BTLA tetramer did not
bind to cells expressing PD-L1 or B7x. Furthermore, our B7x-Fc
fusion protein did not bind cells expressing BTLA.
[0681] To identify potential ligands on normal lymphocytes, we next
used a BTLA-Fc fusion protein and BTLA tetramer to stain
splenocytes (FIGS. 33 and 34). As a control, the PD-LIFc fusion
protein showed selective binding to activated but not resting CD4+
T cells and B220+ B cells (FIG. 33), as expected and consistent
with the reported inducibility of PD-1 expression. Notably, our
BTLA-Fc fusion protein showed specific binding to resting CD4+ and
CD8+ T cells but not to B220+ B cells (FIG. 33). In addition, this
binding was greatly reduced after T cell activation by treatment
with antibody to CD3 (anti-CD3) but was not affected by B cell
activation. As B7x is not reported to be expressed by naive T
cells, the binding of the BTLA-Fc fusion protein to T cells is not
consistent with an interaction with B7x. However, we independently
confirmed that B7x was not expressed by T cells by examining the
expression of B7x and several other CD28-B7 family members. B7x
mRNA was most highly expressed in heart and lung but was absent
from spleen, lymph node and naive CD4+ T cells. In contrast, we
confirmed the expected lymphoid-specific expression pattern for
several CD28-B7 family members, including ICOS, PD-1 and BTLA.
[0682] To confirm and characterize the potential ligand on T cells
identified by the BTLA-Fc fusion protein, we next analyzed the
properties of BTLA tetramers binding to lymphocytes (FIG. 34). The
BTLA tetramer showed strong binding to both CD4+ and CD8+ T cells
obtained from both spleen and lymph nodes and bound weakly to non-T
lymphocytes (FIG. 34A). Furthermore, binding to T cells was reduced
after anti-CD3 stimulation (FIG. 34B), similar to our results
obtained with BTLA-Fc fusion proteins (FIG. 33). In contrast,
treatment of splenocytes with antiimmunoglobulin M (anti-IgM) or
lipopolysaccharide did not reduce BTLA tetramer staining of CD4+ T
cells. BTLA tetramers showed very slight binding to resting and
activated B cells (FIG. 34B). We also examined BTLA tetramer
staining in thymic subsets (FIG. 34C). BTLA tetramer staining was
lowest in CD4+CD8+(double-positive) thymocytes and showed more
staining in mature CD4+ or CD8+ thymocytes and double-negative
(CD4-CD8-) thymocytes, again indicating some physiological
regulation of the BTLA ligand. As BTLA tetramer binding was
modulated 48 h after anti-CD3 stimulation of T cells, we did a more
detailed kinetic analysis using DO11.10 T cells activated in vitro
with ovalbumin (OVA) peptide (FIG. 35). Again, BTLA tetramer
binding was regulated during activation, initially increasing by
twofold at 24 and 48 h after antigen-specific stimulation,
decreasing on day 3 and day 4, and increasing again by day 7.
Expression of this BTLA ligand was similar in both T helper type 1-
and T helper type 2-inducing conditions. Thus, BTLA tetramers and
BTLA-Fc fusion proteins have very similar binding properties to
lymphocytes, and a BTLA ligand is expressed by resting T cells and
undergoes regulation during thymocyte development and T cell
activation.
Cloning a BTLA-Interacting Protein
[0683] We constructed a retroviral cDNA library from lymphocytes
and transduced two host cell lines, BJAB and NIH 3T3, that were
negative for BTLA tetramer binding (FIG. 36A). After four
successive rounds of sorting, we obtained lines uniformly positive
for BTLA tetramer staining, which we used to amplify
retrovirus-specific inserts. From BJAB cells, we obtained a
predominant RT-PCR product that we identified as mouse HVEM. From
NIH 3T3 cells we also obtained mouse HVEM as the main component of
RT-PCR isolates. Among the minor retroviral inserts identified from
NIH 3T3 cells, 4-1 BB was the only transmembrane receptor; it also
belongs to the TNFR superfamily.
[0684] We next tested these isolates as candidates for direct
interactions with BTLA tetramers. We expressed full-length cDNA
clones of mouse HVEM, human HVEM, mouse 4-1 BB and mouse LTI3R,
which binds the same ligands (LIGHT and LT.alpha.) as HVEM, in BJAB
cells and analyzed these cells for binding to BTLA tetramers. We
specifically constructed BTLA tetramers from both the C57BL/6 and
BALB/c alleles to identify any potential allelic differences in
binding (FIG. 36B). We found specific binding of both forms of BTLA
tetramers to green fluorescent protein (GFP)-positive BJAB cells
expressing mouse HVEM but not to BJAB cells expressing human HVEM,
mouse 4-1 BB or mouse LTI3R or to GFP-negative uninfected BJAB
cells.
HVEM Induces BTLA Phosphotylation
[0685] We next sought to determine if HVEM could induce BTLA
phosphorylation (FIG. 36C, D). We analyzed BTLA phosphorylation in
EL4 cells using immunoprecipitation immunoblot analysis as
described above. EL4 cells had low expression of BTLA but no
detectable HVEM, as assessed by BTLA tetramer binding. We therefore
examined EL4 cells for BTLA phosphorylation and SHP-2
coimmunoprecipitation after contact with mouse HVEM expressed by
BJAB cells. EL4 cells alone showed neither coimmunoprecipitation of
SHP-2 with BTLA (FIG. 36C) nor direct tyrosine phosphorylation of
BTLA (FIG. 36D). Mixing of EL4 cells with HVEM-expressing BJAB
cells induced both coimmunoprecipitation of SHP-2 with BTLA and
tyrosine phosphorylation of BTLA. In contrast, mixing EL4 cells
with HVEMnegative BJAB cells induced neither coimmunoprecipitation
of SHP-2 with BTLA nor BTLA phosphorylation. As controls,
pervanadate treatment of EL-4 cells induced coimmunoprecipitation
of SHP-2 and tyrosine phosphorylation of BTLA, but BJAB cells
alone, either. HVEM-negative or expressing HVEM, showed neither
SHP-2 coimmunoprecipitation nor BTLA phosphorylation. Thus, these
results show that HVEM can induce BTLA tyrosine phosphorylation and
association with SHP-2.
HVEM-BTLA Interactions are Conserved in Human
[0686] Because tetramers of mouse BTLA bound mouse HVEM but not
human HVEM, we sought to determine if the BTLA-HVEM interaction was
conserved in humans. Therefore, we generated a human BTLA-Fc fusion
protein and characterized its interactions with mouse and human
HVEM (FIG. 36E). The mouse BTLA-Fc fusion protein bound to BJAB
cells expressing mouse HVEM but not cells expressing human HVEM,
confirming the data obtained with mouse BTLA tetramers (FIG. 36B).
In addition, the human BTLA-Fc fusion protein bound to BJAB cells
expressing human HVEM (FIG. 36E). The human BTLA-Fc fusion protein
also bound, although more weakly, to BJAB cells expressing mouse
HVEM. These interactions were specific, as the isotype control
antibody and the B7x-Fc fusion protein did not bind to BJAB cells
expressing either mouse or human HVEM. Thus, the interaction
between BTLA and HVEM occurs in human lymphocytes, as it does in
mouse lymphocytes. Also, although cross-species interactions are
noted for human BTLA and mouse HVEM (FIG. 36E), it seems that this
cross-species interaction is weaker than the intraspecies
interaction.
BTLA Interacts with the CRD I Region of HVEM
[0687] HVEM is a member of the TNFR superfamily and interacts with
the two known TNF family members LIGHT and LT.alpha.. Because HVEM
has multiple ligands, we sought to determine whether we could
detect additional ligands for BTLA. Thus, we compared binding of
BTLA tetramers to wild-type and HVEM-deficient lymphocytes (FIG.
37A). BTLA tetramers showed no detectable specific binding to
HVEM-deficient CD4+ or CD8+ T cells but showed the expected binding
to wild-type T cells. Even the low binding of BTLA tetramer to B
cells was reduced to undetectable amounts in HVEM-deficient B cells
(FIG. 37A). Thus, we found no evidence of additional ligands for
BTLA in mice.
[0688] The interaction between HVEM and LIGHT can be detected with
an HVEM-Fc fusion protein containing the four extracellular CRD
regions of HVEM fused to the Fc region of human IgG1. We therefore
sought to determine whether this HVEM-Fc fusion protein can also
bind BTLA (FIG. 37D). Because LIGHT is expressed by CD11c+DCs but
not by B220+ B cells, we compared the binding of HVEM-Fc fusion
protein to B cells and DCs from wild-type and BTLA-deficient mice
(FIG. 37B). The HVEM-Fc fusion protein bound to wild-type B cells
but not to Btla-/- B cells. In contrast, the HVEM-Fc fusion protein
bound to wild-type DCs with only slightly reduced binding to
Btla-/- DCs. We next compared the binding of HVEM-Fc fusion protein
to wild-type and LIGHT-deficient (Tnfsf14-/-) B cells and DCs (FIG.
37C). The HVEM-Fc fusion protein bound to wild-type and Tnfsf11-/-
B cells and DCs with nearly equal intensity. In addition, HVEM
expression was actually increased in Btla-/- mice compared with
that in wild-type mice. This result might indicate that endogenous
HVEM expression is regulated by interaction with BTLA, similar to
the reported regulation of HVEM expression by LIGHT. Furthermore,
this result formally shows that HVEM expression does not require
BTLA as a `chaperone`. These results might suggest that BTLA is the
only ligand for HVEM on B cells, but such conclusions based solely
on soluble staining reagents may be misleading, and it is possible
that HVEM could also interact with other unknown molecules on B
cells. For DCs, it seems that both BTLA and LIGHT are ligands for
HVEM.
[0689] We sought to identify which domains of HVEM are involved in
BTLA interactions. HVEM has four extracellular CRDs; it binds LIGHT
and LT.alpha. through CRD2 and CRD3 and binds herpes glycoprotein D
through CRD1. We constructed a series of HVEM mutants, including a
mouse HVEM GFP fusion protein, an HVEM deletion mutant lacking the
N-terminal CRD1 as a GFP fusion protein, an intact human HVEM, and
a chimeric HVEM containing mouse CRD1 linked to human CRD2. We
expressed this panel of HVEM mutants in BJAB cells and examined
binding of the mouse BTLA tetramer (FIG. 37D). As expected, the
BTLA tetramer did not bind uninfected BJAB cells but bound to
wild-type mouse HVEM. However, the mouse BTLA tetramer did not bind
to the HVEM mutant lacking CRD1. In addition, BTLA tetramer did not
bind to human HVEM but did bind to the mouse-human chimeric HVEM
(FIG. 37D). As a control, we assessed the amounts of human HVEM
expressed by these cell lines (FIG. 37D), confirming expression of
the human and chimeric HVEM molecules. These results indicate an
important function for the CRD1 domain of mouse HVEM for BTLA
interactions but do not exclude the possibility of a contribution
by other domains.
HVEM Inhibits Antigen-Driven T Cell Proliferation
[0690] HVEM is expressed by several types of cells, including T
cells, B cells and DCs, complicating the analysis of potential
interactions between cells expressing LIGHT, BTLA and HVEM. Thus,
we first sought to confirm the reported costimulatory effects of
LIGHT on CD4+ T cells in our system. We stimulated highly purified
CD4+ T cells with increasing amounts of anti-CD3 in the presence of
various concentrations of plate-bound LIGHT (FIG. 38A). At
suboptimal concentrations of anti-CD3 stimulation, LIGHT strongly
augmented T cell proliferation in a dose-dependent way. At the
highest dose of anti-CD3, the costimulatory effect of LIGHT was
reduced slightly because of an increase in the LIGHT-independent
proliferation. These data confirm reports that LIGHT engagement of
HVEM provides positive costimulation.
[0691] We next tested whether BTLA or HVEM expression by
antigen-presenting cells (APCs) inhibited or activated T cells. For
this, we produced a panel of Chinese hamster ovary (CHO) cells
expressing various combinations of 1-Ad and B7-1 (ref. 18) plus
either BTLA or HVEM using retrovirus transduction and cell sorting.
We confirmed expression of 1-Ad, B7-1, BTLA and HVEM by these cell
lines using flow cytometry. We sought to determine if BTLA
expression by APCs costimulated DO11.10 T cells (FIG. 38B). CHO
cells expressing I-Ad alone supported minimal T cell proliferation,
similar to that seen with T cells and peptide alone. As a positive
control, CHO cells expressing I-Ad and B7-1 supported higher
proliferation in response to OVA peptide. In contrast, BTLA
expression by APCs did not augment T cell proliferation induced by
CHO cells expressing I-Ad alone (FIG. 38B), as did expression of
B7-1, suggesting that BTLA does not provide costimulation to T
cells through HVEM engagement.
[0692] Whereas BTLA, unlike LIGHT, may not activate HVEM, HVEM
seems to activate BTLA, as evidenced by BTLA phosphorylation and
SHP-2 association (FIG. 36C, D). Thus, we sought to determine
whether HVEM expression by APCs influenced T cell proliferation
(FIG. 38C). The peptide dose-dependent proliferation supported by
CHO cells expressing I-Ad alone was reduced when HVEM was
coexpressed on these CHO cells (FIG. 38C). Furthermore, as
expected, B7-1 increased T cell proliferation induced by peptide
and I-Ad (FIG. 38D), shifting the dose-response to lower
concentrations of peptide. Again, coexpression of HVEM on these CHO
cells reduced peptide-dependent T cell proliferation. The
inhibition produced by HVEM at the highest peptide concentrations
was smaller than the inhibition seen with intermediate
stimulation.
[0693] We extended this analysis using T cells labeled with
carboxyfluorescein diacetate succinimidyl diester (CFSE; FIG. 39).
In addition, we tested whether the inhibitory effect of HVEM on T
cell proliferation required BTLA by using Btla-/- DO11.10 T cells.
Using CHO cells lacking B7-1 expression, we did not note T cell
proliferation at the lowest dose of OVA peptide (0.03 .mu.M) on
days 3 and 4 (FIG. 39A). However, higher peptide concentrations
(0.3 .mu.M) induced T cell proliferation on days 3 and 4. In these
conditions, expression of BTLA on CHO cells had no effect on T cell
proliferation at anytime. However, expression of HVEM on CHO cells
greatly reduced T cell proliferation, which occurred only in
wild-type DO11.10 T cells, not Btla-/- T cells, and was evident on
days 3 and 4 after activation.
[0694] We next examined the effects of HVEM on T cell proliferation
in response to antigen presentation by CHO cells expressing B7-1
(FIG. 39B). Again, B7-1 increased T cell proliferation induced by
peptide and I-Ad, shifting the dose-response to lower
concentrations of peptide, as demonstrated by larger numbers of
cellular divisions at lower doses of peptide; this was clearly
evident on day 3 as well as day 4. In these conditions,
coexpression of BTLA on CHO cells had no effect on T cell
proliferation. In contrast, coexpression of HVEM on CHO cells
caused a reduction in proliferation of wild-type DO11.10 T cells,
but this was evident only at the lowest peptide dose and was
evident only on day 3, not day 4, after T cell activation. This
inhibition of T cell proliferation was specific to BTLA, as we
found it only in wild-type but not Btla-/- T cells. In summary,
HVEM inhibits both costimulation-independent and
costimulation-dependent proliferation, but is more effective in
blocking activation of antigen stimulated T cells at low B7-1
expression. Furthermore, HVEM-mediated inhibition of T cell
proliferation requires BTLA expression by T cells.
Methods for Example 13
Mice
[0695] C57BL/6 and BALB/c mice (Jackson Labs) were bred in our
facility. Btla-/- mice were backcrossed to BALB/c for nine
generations and were subsequently crossed onto the DOI 1.10 T cell
receptor-transgenic background. LIGHT-deficient mice were
previously described and HVEM-deficient (Tnfrsfl4-/-) mice will be
described elsewhere (data not shown).
Plasmids and Retroviral Constructs
[0696] The sequences of all oligonucleotides are provided in
Supplementary Table 1 online Sedy et al., Nature Immunology (2005)
6:90-98. For preparation of B7x-B7h-GFP-RV, a PCR product made with
primers 5'Bgl2 mB7x and B7xB7h bottom using IMAGE cDNA clone
3709434 as the template, plus a PCR product made with primers
B7xB7h top and 3'RI GFP using the B7h-GFP plasmid (a gift from W.
Sha, University of California, Berkeley, Calif.) as the template,
were annealed and amplified with Pfu polymerase with primers 5'Bgl2
mB7x and 3'R1 GFP. This product, encoding the B7x extracellular
domain, B7h transmembrane and cytoplasmic domains fused to GFP, was
digested with BgIII and EcoRI and was cloned into IRES-GFP-RV that
had been digested with BgIII and EcoRI.
[0697] The plasmid huHVEM-IRES-GFP-RV was produced by amplification
of huHVEM with primers 5'Bgl2 huHVEM and 3'Xho1 huHVEM using IMAGE
cDNA clone 5798167 (Invitrogen) as the template, followed by
digestion with BgIII and XhoI and ligation into Tb-lym-IRES-GFP-RV
that had been digested with BgIII and XhoI, replacing the Tb-lym
cDNA with that of huHVEM. Similarly, m4-1 BB-IRES-GFP-RV was
prepared with primers 5'Bgl2 m4-1 BB and 3'Xho1 m4-1 BB using
library plasmid as the template, followed by digestion with BgIII
and XhoI and ligation into Tb-lym-IRES-GFP-RV. The plasmid mLT
R-IRES-GFP-RV was prepared with primers 5'Bg12 mLT R and 3'SaI1 mLT
R using IMAGE cDNA clone 5293090 (Invitrogen) as the template,
followed by digestion with BgIII and SalI and ligation into
Tb-lym-IRES-GFP-RV. The plasmid mHVEM-FL-IRES-GFP-RV was similarly
prepared with primers 5'Bgl2 mHVEM and 3'Xho1 mHVEM using, as the
template, cDNA from library infected BJAB cells sorted for BTLA
tetramer binding, followed by digestion with Bg111 and XhoI and
ligation into Tb-lym-IRES-GFP-RV. Three amino acid changes (N58S,
K92R and E128G) in mouse HVEM cDNA cloned from the retrovirus
library, compared with that of mouse HVEM cDNA from the 129 SvEv
mouse strain, were implemented by Quick Change mutagenesis
(Stratagene) to generate mHVEM(129)-IRES-GFP-RV with serial
application of the primers S-N top plus S-N bot; R-K top plus R-K
bot; and G-E top plus G-E bot.
[0698] The plasmid mHVEM-FL-GFP-RV was made from two PCR products,
with primers 5'Bgl2 mHVEM and mHVEM/GFP bot using
mHVEM-FL-IRES-GFP-RV as the template, and primers mHVEM/GFP top and
3'GFP+SaI using mHVEM-FL-IRES-GFP-RV as the template; the PCR
products were annealed, amplified with primers 5'Bgl2 mHVEM and
3'GFP+SaI, digested with BgIII and SaII and ligated into
IRES-GFP-RV that had been digested with BgIII and SaII. The plasmid
mHVEM-FL-GFP-RV CRD1 was made by Quick Change mutagenesis from
mHVEM-FL-GFP-RV with primers mHVEM dl top and mHVEM dl bot. The
plasmid m/hHVEM-IRES-GFP-RV (mouse CRD1 fused to human CRD2) was
made from two PCR products, with primers 5'Bgl2 mHVEM and m/hHVEM
bot using mHVEM-FL-IRES-GFP-RV as the template, and primers m/hHVEM
top and 3'Xho hHVEM using hHVEM-IRES-GFP-RV as the template; the
PCR products were annealed, amplified with primers 5'Bgl2 mHVEM and
3'Xho huHVEM, digested with BgIII and XhoI and ligated into
Tb-lym-IRES-GFP-RV that had been digested with BgIII and XhoI.
C57BL/6-BTLA-GFP-RV, a BTLA-GFP chimera, was prepared from two PCR
products, with primers J1ORV1 (BgI 2) and 3'J10+10 using C57BL/6
BTLA cDNA as the template, and primers 5'GFP+10 and 3'GFP+SaI using
GFP cDNA as the template; the PCR products were annealed, amplified
with J1ORV1 (BgI 2) and 3'GFP+SaI, digested with BgiII and SaII and
ligated into Tb-lym-IRES-GFP-RV that had been digested with BgIII
and XhoI. A cytoplasmic deletion of this construct,
BTLA-trunc-GFP-RV, was made by site-directed mutagenesis
(Stratagene) with primers mj11trunc top and mj11trunc bottom.
[0699] PD-1-GFP-RV was made by amplification of the PD-1 coding
region with primers PD15' and PD13' using PD-1 cDNA as the template
(a gift from T. Honjo, Kyoto University, Kyoto, Japan); the PCR
product was digested with BgIII and BamHI and was cloned into
AIB3-GFP MSCV that had been digested with BgiII and BamHI (a gift
from W. Shay. Similarly, PD-L1-GFP-RV was made by amplification of
the region encoding PD-L1 with primers PD-L1G5' and PD-LIG3' using
PD-L1 cDNA (a gift from T. Honjo) as the template; the PCR product
was digested with Bg111 and BamHI and was ligated into AIB3-GFP
MSCV.
[0700] PD-1 pET28 was made by amplification of the immunoglobulin
domain of PD-1 with primers PD1Tet5' and PD1Tet3' using PD-1-GFP-RV
plasmid as the template, followed by digestion with NcoI and BamHI
and ligation into MLL1-pET28 (a gift from D. Fremont, Washington
University, St. Louis, Mo.) that had been digested with NcoI and
BamHI. Similarly, B6-BTLA pET28 was made by amplification of the
extracellular immunoglobulin domain of BTLA with primers
J11TetMus5' and J11TetB63' using C57BL/6 BTLA-GFP-RV plasmid as the
template, followed by digestion with NcoI and BamHI and ligation
into MLL1-pET28. Similarly, BALB-BTLA pET28 was made with primers
J11TetMus5' and J11TetWEHI3' using mJ11W1 as the template, and
digestion with NcoI and BamHI and ligation into MML1-pET28. The
immunoglobulin domain was `corrected` to authentic BALB/c allelic
sequence (data not shown) by serial mutagenesis with primers
W1e23k5' and W1e23k3' followed by primers W1h38n3B and
W1h38n5C.
Fc Fusion Proteins
[0701] For the creation of CD47-Fc-.alpha.TP-ires-GFP-RV, a
bicistronic retroviral vector for Fc fusion proteins, CP318 (a gift
from Lewis Lanier, University of California, San Francisco, Calif.)
was digested with PfIF I and NotI, treated with Vent polymerase and
ligated into mIL-12R-ires-GFP-RV that had been digested with BgIII
and XhoI and treated with mung bean nuclease. The plasmids
mBTLA-Fc-.alpha.TP-ires-GFP-RV, mB7x-Fc-.alpha.TP-ires-GFP-RV,
mPD-L1-Fc-.alpha.TP-ires-GFP-RV and hBTLA-Fc-.alpha.TP-ires-GFP-RV
were made by ligation of the following XhoI-digested PCR products
containing the immunoglobulin domains regions of these genes into
the XhoI site of CD47-Fc-.alpha.TP-ires-GFP-RV. The product mBTLA
was made with primers 5' xho mJI 1 dodecamer and 3' xho mJ 11
dodecamer using as a template the C57BL/6 splenocyte phage library
(Stratagene). The product mB7x was made with primers 5' xho mB7x
dodecamer and 3' xho mB7x dodecamer using IMAGE cDNA clone 3709434
(Invitrogen) as the template. PD-L1 was made with primers 5' xho
mPDL2 dodecamer and 3'Xho PDL1 dodecamer using pBacPAK8-PDL1 (a
gift from T. Honjo) as the template. Human BTLA was made with
primers 5'Xho hJ111g and 3'Xho hJH Ig using hJ11(corr)ires-GFP-RV
as the template.
[0702] Fc fusion proteins were produced by transfection of Phoenix
E cells, were purified with Affi-prep protein A columns (Biorad)
and were dialyzed against PBS and stored at -70.degree. C. For flow
cytometry, cells were stained with 200 ng of purified Fc-fusion
protein or, for hBTLA-Fc fusion protein, 1 ml of supernatant,
followed by phycoerythrin-conjugated anti-human IgG (heavy plus
light) that had been adsorbed against proteins from mouse, rat, cow
and other species (Jackson Immunoresearch), and anti-mCD4-tricolor
(Caltag) and anti-mB220-fluorescein isothiocyanate (FITC;
BD-Pharmingen).
Production of Tetramers
[0703] Tetramers produced with plasmid PD-1 pET28, B6-BTLA pET28 or
BALB-BTLA pET28 were transformed into BL21-CodonPlus (DE3) RIPL
Competent Cells (Stratagene) essentially as described. Purified
proteins were biotinylated in vitro with BirA ligase (Avidity),
purified by gel filtration and concentrated. Tetramers were formed
by the addition of biotinylated protein to
streptavidin-phycoerythrin at a molar ratio of 1:4.
Cell Lines
[0704] BJAB and NIH 3T3 cells were from A. Chan (Washington
University, St. Louis, Mo.); EL-4 cells were from T. Ley
(Washington University, St. Louis, Mo.); 293T cells were from R.
Schreiber (Washington University, St. Louis, Mo.); CHO cells were
from A. Sharpe (Harvard University, Boston, Mass.); and Phoenix A
and E packaging cells were from American Type Culture Collection.
Retrovirus constructs were packaged either in Phoenix A or E cells
by calcium phosphate transfection as described. CHO cells were
transduced by retrovirus packaged by transfection of 293T cells
with pYITG plus pCGP (a gift from W. Sha) and were sorted for GFP
to more than 95% purity, followed by staining with 6A6 (anti-BTLA)
or BTLA-phycoerythrin tetramers.
Retrovirus Library
[0705] Purified BALB/c and C57BL/6 splenocytes were left
unstimulated or were activated for 48 h with plate-bound anti-CD3
(500A.2 ascites) or soluble anti-IgM (Jackson Immunoresearch), then
RNA was purified (RNeasy mini kit; Qiagen) and mRNA was made with
the Nucleotrap mRNA purification kit (Clontech), full-length cDNA
was made with the SMART cDNA Library Construction Kit (Clontech)
and double-stranded cDNA was made by long-distance PCR with 5'PCR
primer and CDS III/3'PCR primer; the PCR products were digested
with Sfi1, size fractionated, amplified cDNA ligated into
Sfi1-digested MSCV-ires-Thy1.1 retrovirus vector (a gift from W.
Sha) and were transduced into XL-10 gold (Stratagene) for a library
transcript complexity of 2.times.10.sup.6. The library plasmid was
purified without further amplification by CsCl gradient
ultracentrifugation. Infected NIH-3T3 cells (8.times.10.sup.6) and
infected BJAB cells (6.times.10.sup.6) were generated from
retrovirus made by calcium phosphate transfection of Phoenix E
cells; the total number of infected cells was assessed by
anti-Thy1.1-FITC (eBioscience) staining. Serial rounds of cell
sorting used anti-Thy1.1-FITC and BALB/c and C57BL/6 BTLA
tetramers. When the sorted cells were more than 80% positive for
Thy1.1 and BTLA tetramer, RNA was prepared and reverse-transcribed,
cDNA was amplified with Taq polymerase and primers Sfi 5' and Sfi
3', and PCR products were cloned into pGEM-T Easy (Promega).
T Cell Purification and Stimulation
[0706] T cells were purified (>90%) with anti-CD4 magnetic beads
(Miltenyi) and, where indicated (FIGS. 38B-D, 39) by subsequent
sorting for populations that were negative for B220-FITC and
CD11c-phycoerythrin and positive for CD4-CyChrome (>98%). For T
cell stimulation with anti-CD3 and LIGHT, 2C11 (BD Pharmingen) was
coated onto 96-well plates, followed by LIGHT (PeproTech) at the
indicated doses (FIG. 38A). Purified T cells were plated at a
density of 1.times.10.sup.6 cells/ml in 100 .mu.l media per well.
CHO cells were treated in media for 16 h at 37.degree. C. with 50
.mu.g/ml of mitomycin C (Sigma), were washed twice in PBS and were
plated at a density of 1.times.10.sup.6 cells/ml in 100 .mu.l media
in 96-well plates for proliferation assays or in 1 ml media in
24-well plates for CFSE analysis. For proliferation assays,
purified T cells were plated directly onto CHO cells at a density
of 1.times.10.sup.6 cells/ml in 100 .mu.l media and OVA peptide.
After 48 h, cells were pulsed for 12 h with 1 .mu.Ci/well of
[.sup.3H]thymidine. For CFSE analysis, purified T cells were washed
three times with PBS, were incubated for 8 min at 20.degree. C.
with 1 .mu.M CFSE (Molecular Probes), were `quenched` with fetal
calf serum, were washed twice with media and were plated directly
onto CHO cells at a density of 1.times.10.sup.6 cells/ml in 1 ml
media plus OVA peptide. After 3 and 4 d, cells were stained with
CD4-FITC and were analyzed by flow cytometry.
Immunoblot Analysis
[0707] Pervanadate stimulation was done as described. For
cell-mixing experiments, 25.times.10.sup.6 EL4 cells were mixed
with 25.times.10.sup.6 BJAB cells expressing GFP or
25.times.10.sup.6 BJAB cells expressing mouse HVEM in 1 ml for 4
min at 37.degree. C. and were lysed as described. Extracts were
precleared with protein G-Sepharose (Pharmacia), followed by
immunoprecipitation with 9 .mu.g of 6A6 (anti-mBTLA) or isotype
control Armenian hamster IgG (Santa Cruz) and 40 ul protein
G-Sepharose (Pharmacia), then were washed and analyzed by SDS-PAGE.
Immunobiot analyses for SHP-2 and phosphotyrosine were done as
described in Watanabe et al, Nat. Immunol. (2003) 4:670-679 and
Gavrieli et al, Biochem. Biophys. Res. Commun. 312:1236 1243
(2003).
[0708] For further details regarding Example 13, including
references, see Sedy et al., Nat. Immunol., 6:90-98, which is
expressly incorporated herein in its entirety by reference.
Example 14
BTLA Polymorphism and BTLA Binding Antibodies
Allelic Polymorphisms in BTLA
[0709] We previously generated BTLA cDNA from several sources,
including from the cell line WEHI 231, a commercial murine C57BL/6
splenocyte cDNA library, and 129SvEv mice, finding several
polymorphisms within the BTLA Ig domain coding sequence. To
determine the basis of differences, we sequenced the coding region
for the BTLA Ig domain from genomic DNA of several inbred and wild
mouse strains (FIG. 40). Among 23 strains, we identified three
distinct alleles of BTLA, differing in their predicted amino acid
sequence and potential predicted disulphide bonding pattern (FIG.
40A). The allele represented by BALB/c was present in CBA/J, SJL/J,
New Zealand White (NZW), BXSB, C3H/J, New Zealand Black (NZB/BinJ),
NOD, 129SvEv, and 129SWJ (FIG. 40B). A second allele, represented
by the strains MLR/Ipr, AKR, SWR, CALB/RK, and DBA/2J, differed
from the BALB/c allele at only one amino acid, containing histidine
rather than asparagine at residue 38 of the BTLA protein. These two
alleles each have five cysteine residues within the Ig domain,
predicting two disulfide bonds and one unpaired cysteine. The third
allele, represented by C57BL/6, was also present in B10.PL and
several wild-derived inbred strains, and differed from the BALB/c
and MLR/Ipr alleles at 10 and 11 amino acid residues, respectively
(FIG. 40A). Notably, the C57BL/6 allele has a cysteine at amino
acid residue 49, making six total cysteine residues with three
predicted disulfide bonds in the BTLA Ig domain. As a control, we
found no sequence polymorphisms in the PD-1 Ig domain from BALB/c,
MLR/Ipr, and C57BL/6 (data not shown).
Generation of Allele-Specific mAbs to Murine BTLA
[0710] To generate anti-BTLA mAbs, we immunized Armenian hamsters
and BTLA-/- BALB/c mice with recombinant Ig domain of the C57BL/6
BTLA allele. To allow the identification of Abs that could
potentially recognize either the BALB/c or C57BL/6 allele of BTLA,
hybridoma supernatants were screened for binding to BJAB cells
expressing either the C57BL/6 or BALB/c allele of BTLA as a GFP
fusion protein. One hamster anti-BTLA Ab, 6A6, was identified that
reacted only with the C57BL/6, but not the BALB/c, allele of BTLA
(FIG. 41A). The majority of the murine anti-BTLA mAbs reacted with
both the C57BL/6 and BALB/c BTLA alleles, including 6F7, 6G3, 8F4,
and 3F9.D12 (FIG. 41B). One murine Ab, 3F9.C6, reacted only with
C57BL/6 BTLA, and not with BALB/c BTLA. Another Ab, 6H6, reacted
with both alleles, but stained the C57BL/6 allele more highly than
the BALB/c allele. For each of these Abs, staining was observed on
wild type splenocytes, but not splenocytes of BTLA-/- mice (FIG.
41C, and data not shown), suggesting that these Abs in fact
recognize BTLA, and react with native BTLA as well.
[0711] To further assess how these Abs interact with BTLA, we
characterized their behavior in IP and Western blot analysis (FIG.
41D and E). The pan-specific Abs 6F7 and 6G3 each specifically
immunoprecipitated both the C57BL/6 and BALB/c BTLA-GFP fusions
proteins from BJAB cells (FIG. 41D, bottom panel). Importantly, the
C57BL/6-specific 6A6 Ab did immunoprecipitate the C57BU6 BTLA
allele, but not the BALB/c allele (FIG. 41D, compare lanes 3 and
6), indicating that the allelic specificity observed by FACS
analysis extends to its behavior in IP Western blot analysis. Also,
these interactions seen in IP Western blot analysis were specific
because no BTLA was immunoprecipitated using mouse or hamster IgG1
as an isotype control (FIG. 41D, lanes 7-10).
[0712] Notably, although equivalent amounts of each BTLA allele
were immunoprecipitated when assessed by immunoblotting for the GFP
epitope of the fusion proteins, detection of the Ig domain by IP
Western blot analysis was not equally efficient. Following
immunoprecipitation, the C57BL/6 BTLA Ig domain was detected much
more strongly than the BALB/c allele by 6G3 and 6F7, both
pan-specific anti-BTLA Abs, (FIG. 41D, top panel, lanes 1, 2, and
4-6). These results may indicate differential sensitivity between
alleles for recognition or detection of the Ig domains, even using
pan-specific Abs, which could result from differential sensitivity
to denaturation of the antigenic epitope. Whatever the cause, it is
necessary to consider this fact when using IP Western blot analysis
in comparing BTLA from varying allelic backgrounds. Finally,
certain Abs allow coimmunoprecipitation of BTLA-associated
proteins. For example, IP Western blot analysis using 6A6
reproduces the known specific and inducible coassociation of SHP-2
with BTLA following pervanadate treatment (FIG. 41E).
Mapping Antigenic Epitopes Recognized by Anti-BTLA Abs
[0713] To map which of the polymorphic residues differing between
BALB/c and C57BL/6 BTLA were involved in strain-specific reactivity
of 6A6 and 3F9.C6, we used yeast display technology. We first
expressed the BTLA Ig domain as an Aga2 fusion protein, and then
generated a series of mutant BTLA Ig domains with single amino acid
substitutions at the polymorphic residues, replacing BALB/c
residues into the C57BL/6 allele one residue at a time (FIG. 42).
This series of wild type and mutant BTLA proteins were then
analyzed for reactivity with pan-specific anti-BTLA mAbs and two
B6-specific Abs, 6A6 and 3F9.C6 (FIG. 42). As a positive control,
we confirmed that the pan-specific anti-BTLA mAb 6F7 recognized the
wild type C57BL/6 BTLA Ig domain, and also recognized each of the
single residue substitutions of BTLA (FIG. 42, left column), as
expected for pan-specific reactivity. In contrast, the two
C57BL/6-specific Abs recognized some, but not all of BTLA mutants.
Specifically, 6A6 showed a very selective loss of reactivity only
with the Q27E, C49W, and Q66R substitutions, indicating that these
residues are involved in the strain-specific recognition of BTLA. A
distinct pattern of reactivity was observed with 3F9.C6, with a
selective loss of reactivity with the R107W substitution and
reduced reactivity with the Q27E substitution. Also, whereas 6A6
reactivity is sensitive to the C49W substitution, which disrupts
one of three predicted disulphide bonds, 3F9.C6 reactivity remains
in this substitution. These results indicate that the C57BL/6
specificity of these two Abs derive from interactions with the
distinct, but polymorphic, region of the BTLA Ig domain.
[0714] In summary, at least two of the BTLA alleles can be
distinguished by their antigenic structure, as shown by two
C57BL/6-specific anti-BTLA Abs. Importantly, we also identified
several pan-specific anti-BTLA Abs, which now allow direct
comparisons of the fine specificity of tissue expression of native
BTLA expression between various murine strains.
Distribution and Expression of Murine BTLA
[0715] In our previous studies, we were restricted to analyzing
BTLA expression either by mRNA expression or by using epitope-tags
because we lacked Abs to native BTLA. Conceivably, we failed to
detect low but physiologically important levels of BTLA on certain
lymphocyte subsets for this reason. Thus, we examined BTLA surface
expression on various lymphoid subsets again, using both
allele-specific Ab 6A6 and pan-specific Ab 6F7 (FIG. 43).
[0716] First, BTLA was expressed uniformly on B cells at levels
that were similar for C57BL/6 and BALB/c mice (FIG. 43A). CD4+ and
CD8+ T cells expressed lower levels of BTLA compared with B cells,
but again, at levels that were similar for C57BL/6 and BALB/c mice.
For 6A6, we found that a subpopulation of CD11b+ cells, CD11c+
dendritic cells, and DX5+ cells were positive for BTLA expression,
and again identified only in C57BL/6 cells as expected (FIG. 43A,
middle row). Using the pan-specific 6F7 Ab, we found that B cells
express the highest levels of BTLA, again at levels similar between
C57BL/6 and BALB/c mice, with lower levels expressed in CD4 and CD8
T cells (FIG. 43A, lower row). Interestingly, using the
pan-specific reagent 6F7, we found that BTLA was expressed on
CD11c+BALB/c cells at levels similar to CD11c+C57BL/6 cells, but
that BTLA was only expressed on CD11b+macrophages and DX5+ NK cells
from C57BL/6 mice, but not in BALB/c mice (FIG. 43A, lower row).
The fact that 6F7 detects BTLA expression on B cells, T cells, and
CD11c+ cells from both BALB/c and C57BL/6 mice serves as a control
for its ability to bind BTLA from both strains. Thus, the selective
binding of 6F7 to DX5+ and CD11b+ cells only in C57BL/6, not BALB/c
mice, indicates a difference between these strains for BTLA
expression by these cell types. Thus, these strains appear to have
a distinct difference in the cell types expressing detectable BTLA,
explaining the differences between BTLA expression reported
previously.
[0717] We also examined BTLA expression in splenic B cell
populations (FIG. 43B). BTLA expression was detected at the highest
levels on follicular B cells (1gMlowCD21/CD35int), and at reduced
levels on marginal zone B cells (1gMhighCD21/CD35high) and
transitional B cells (1gMlowCD21/CD35low) (FIG. 43B). Notably,
because the 6F7 pan-specific Ab was used for analysis, we can also
conclude that the levels on each subpopulation of B cells are
similar between C57BL/6 and BALB/c mice (FIG. 43B).
[0718] We next examined BTLA expression in thymocyte and B cell
development (FIG. 44). In thymus, BTLA was expressed at highest
levels on mature CD4+ T cells, and at slightly reduced levels on
CD8+ T cells (FIG. 44A). BTLA expression on immature CD4-CD8- T
cells or CD4+CD8+ double positive T cells was nearly undetectable
(FIG. 44A). In bone marrow, BTLA was expressed at the highest
levels on B220highIgM+ mature B cells (FIG. 44B), and was detected
at relatively low levels on B2201ow/IgM+ immature B cells. BTLA
expression was undetectable on B220+1gM-pro-B cells and pre-B
cells. Further, we found no differences between C57BL/6 or BALB/c
mice for the levels of BTLA expression on the thymocyte and bone
marrow populations.
[0719] Finally, we examined the BTLA expressed on CD4+ T cells
under various conditions of activation and polarization by
cytokines (FIG. 45A). BTLA surface expression on resting CD4+ T
cells was induced by 10-fold on day 2 following activation with Ag
and APCs, decreased by day 4, and was nearly undetectable by day 7
after activation (FIG. 45A). The rapid increase in BTLA expression
by day 2 on Ag-activated CD4+ T cells occurred both in Th1-inducing
or Th2-inducing conditions (FIG. 45A). Upon secondary T cell
activation, BTLA was again highly induced 2 days following
activation, again in both Th1 and Th2 cultures (data not shown).
However, tertiary activation of T cells revealed selective
induction in the Th1 cultures, but not in the Th2 cultures (FIG.
45A). These results suggest that BTLA expression on CD4+ T cells is
initially controlled primarily by T cell activation and not by
factors governing Th1 or Th2 differentiation. The delayed loss of
BTLA inducibility in Th2 cells might suggest a silencing process
rather than a Th1-specific pathway for induction, which would be
consistent with our initial finding that BTLA expression is not
dependent on Stat4 or Stat1. Finally, the rapid modulation of BTLA
expression, peaking on day 2 and extinguished by day 7, suggests
that it may act in the mid-phases of T cell activation following
interactions with APCs.
[0720] In contrast to the activation-dependent expression of BTLA
seen in CD4+ T cells, BTLA expression on B cells was maintained at
high levels throughout activation by LPS or anti-IgM stimulation
(FIG. 45B). These results differ slightly from the reported 3- to
10-fold decrease in BTLA expression following LPS activation of B
cells. Nonetheless, our results agree with that report in the
finding of high levels of BTLA expression on B220+ B cells in the
periphery, and to some degree, the constitutive nature of its
expression.
Selective Induction of BTLA on Anergic T Cells
[0721] Previously, a method of anergy induction for naive CD4+ T
cells was developed that involves adoptive transfer of Ag-specific
CD4+ T cells into recipients expressing Ag on somatic tissues.
Specifically, clone 6.5 transgenic T cells, reactive to HA peptide
110-120 presented by I-Ad, become anergic when transferred into
recipient mice expressing a membrane bound form of HA targeted for
expression on lung and prostate tissue. We analyzed BTLA expression
following T cell transfer on various days after transfer using
Affymetrix gene arrays and FACS (FIG. 46, A and B). We found that
BTLA mRNA was highly induced in these anergic CD4+ T cells in this
system, compared with CD4+ T cells activated by Ag-expressing
vaccinia virus (FIG. 46A). At 2 days after transfer, BTLA
expression by T cells undergoing anergy induction was twice the
level of naive T cells, and significantly higher than activated T
cells. This induction was more evident by day 3 and day 4 following
transfer, with BTLA expression about 3-fold higher than in naive T
cells. By contrast, BTLA levels were substantially reduced in fully
activated T cells compared with naive or anergic T cells at these
times (FIG. 46A). As a control, myosin Vila, a constitutive
"housekeeping" gene, showed essentially no change in these three
conditions over these times. Thus, BTLA mRNA appears to decline
more rapidly than BTLA surface protein in activated T cells because
activated T cells express peak BTLA surface levels at day 2 (FIG.
45), but show reduced BTLA mRNA (FIG. 46B). These observations are
consistent with the reduced BTLA surface expression by day 4 and
the essentially undetectable BTLA expression by day 7.
[0722] We next measured BTLA expression by FACS under conditions of
anergy induction or activation (FIG. 14B). Notably, the highest
levels of BTLA surface expression coincided with induction of
anergy in vivo. Specifically, 6 days after transfer, anergic T
cells expressed about 10-fold higher BTLA than naive T cells, and
about 3-fold higher than in vivo-activated T cells (FIG. 46B). We
verified that the CD4+ T cells transferred into HA-expressing
recipients did become anergic as defined by lack of proliferation
(FIG. 46C), consistent with previous reports. For comparison, we
also wished to evaluate BTLA expression on conventional naive CD4+
T cells (CD4+CD25-) T cells or T regulatory cells (CD4+CD25+)
either as resting cells ex vivo or after in vitro activation with
anti-CD3 (FIG. 46D). As expected, BTLA was expressed at low levels
on naive T cells, and was induced about 10-fold 36 h after anti-CD3
treatment. Freshly isolated T regulatory cells expressed similar
levels of BTLA as freshly isolated naive CD4+ T cell, but showed
only a slight increase after treatment with anti-CD3 (FIG. 46D). As
a control, we confirmed that T regulatory cells, but not naive T
cells, expressed PD-1, consistent with previous reports. As a
further control, we showed that the isolated CD25+ T regulatory
cells failed to proliferate in vitro, in contrast to the robust
proliferation of freshly isolated naive T cells (FIG. 46E). In
summary, BTLA shows a pattern of expression that is somewhat
distinct from that of CTLA-4 and PD-1 in terms of its response to
anergy induction and expression by T regulatory cells.
Role of BTLA in T Cell-Independent Ab Responses
[0723] Our initial analysis of BTLA was motivated by consideration
of its role in T cell activation. However, the fact that B cells
express the highest level of BTLA, and the constitutive nature of
this expression, motivated a second examination of its effect on Ab
production. In our study, we examined T cell-independent Ab
responses using immunization with NP-Ficoll in wild-type mice or
BTLA-/-129SvEv mice, which express the BALB/c allele of BTLA. We
immunized cohorts of mice with one injection of NP-Ficoll in alum
and measured production of anti-NP Abs of specific isotypes on day
14 (FIG. 47). For the isotypes IgM, IgG1, IgA, we found no specific
changes in levels of anti-NP Abs. For IgG2a or IgG2b, we found only
slight increases in anti-NP Abs in the BTLA-/- compared with
wild-type mice. However, for Abs of the IgG3 isotype, which is
primarily associated with T-independent responses, we found an
about 2-fold increased in anti-NP-specific Abs in BTLA-/- mice
compared with wild-type mice. The size of this difference is
consistent with the relatively modest increases in B cell and T
cell proliferation responses described for BTLA-/- cells previously
by both our report and by others, and is consistent with an
inhibitory rather than activating role of BTLA. However, the
relatively modest magnitude of this effect could also be an
indication that BTLA expression by B cells may serve a purpose
other than cell-intrinsic signaling, such as perhaps delivery of a
signal toward cells expressing ligands for BTLA.
Methods for Example 14
[0724] The following Abs used for FACS analysis were from BD
Pharmingen: CD4-CyChrome (RM4-5), CD8-FITC (53-6.7),
B220-allophycocyanin (RA3-6B2), CD11b-FiTC (M1/70),
CD11c-FITC(HL3), DX5-FITC, I-Ad-PE (AMS-32.1), I-Ab-PE (AF6-120.1),
IgM-PerCP Cy5.5 (R6.60.2), CD21/CD25-FITC (7G6),
CD25-allophycocyanin (PC61), CD62 ligand-FITC (MEL-14),
Thy1.1-PerCP (OX-7), goat anti-mouse Ig-PE, mouse
anti-Armenian/Syrian hamster IgG-PE (mixture), Streptavidin
(SA)-PE, SA-CyChrome, and SA-aliophycocyanin. KJ1-26 Tricolor,
hamster IgG-biotin, and murine IgG1-biotin were from Caltag
Laboratories. All FACS analysis included an initial incubation with
2.4G2 (anti-CD16/CD32; BD Pharmingen) to block Fc receptor
interactions. DO11.10 TCR transgenic mice were as described. C3
hemagglutinin (HA) high mice were as described. Immunoprecipitation
(IP) Western blot analysis was conducted as previously described.
Conditions used to induce Th1 and Th2 development were as
previously described.
Sequencing of BTLA and PD-11g domains
[0725] Exon 2 of BTLA or PD-1, encompassing the Ig domain, was
amplified by PCR from genomic DNA from a panel of mouse strains
previously described (23) using Easy-A High Fidelity PCR Cloning
Enzyme (Stratagene) and the following intronic primers: BTLA
(sense) ATGGTCCTTCTAAGAGTGAAC (SEQ ID NO: 70), (antisense)
ATAGATGGTCTGGGGTAGATC (SEQ ID NO: 71) and PD-1 (sense)
CAGGCTCCTTCCTCACAGC (SEQ ID NO: 72), (antisense)
CTAAGAGGTCTCTGGGCAG-3'(SEQ ID NO: 73).
[0726] PCR products were cloned into the pGEM-T Easy vector
(Promega) and inserts from at least three individual subclones from
each strain were sequenced using the T7 universal primer.
Generation of Soluble BTLA Ig Domain
[0727] The Ig domain of C57BL/6 BTLA was PCR amplified from cDNA
using the following primers: BTLA (sense)
CATGCCATGGAGAAAGCTACTAAGAGGAAT (SEQ ID NO: 74) and BTLA (antisense)
CGGGATCCTGAAGAGTTTTGAGTCCTTTC-3' (SEQ ID NO: 75). The product was
subcloned into the pET28 vector (Novagen) that had been modified to
contain a BirA biotinylation sequence (GGGLNDIFEAQKI EWHE) (SEQ ID
NO: 76) onto the C terminus of the BTLA Ig domain. Proteins were
expressed as insoluble inclusion bodies in BL21 (DE3) Codon Plus
RIL cells (Stratagene) and refolded as described.
Production of mAbs to BTLA
[0728] Armenian hamsters or BALB/c background BTLA-/- mice were
immunized with 100 .mu.g of refolded C57BL/6 BTLA Ig domain protein
in CFA, boosted biweekly with 100 .mu.g of protein in IFA, and
received a final i.v. boost 3 days before fusion. Splenocytes were
fused with the P3X63Ag8 myeloma, and hybridoma supernatants
screened for binding to BJAB cells expressing either C57BL/6 or
BALB/c BTLA Ig domains as GFP fusion proteins. The BTLA-GFP chimera
was prepared by splicing by overlap extension (SOEing). A PCR
fragment containing the BTLA cDNA with a 3' tail annealing to the
5' end of GFP was amplified by PCR made using Vent polymerase, the
primers J10RV1-BgIII (AGCTCTGAAGATCTCTAGGGAGGAAG) (SEQ ID NO: 77)
and 3' J10+10 (CCTTGCTCACACTTCTCACACAAATGGATGC) (SEQ ID NO: 78)
with DOI 1.10 BTLA cDNA as template. A second fragment containing
GFP cDNA, without its start codon, with a 5' tail annealing to the
3' end of BTLA was amplified by PCR using Vent polymerase and the
primers 5' GFP+10 (TGTGAGAAGTGTGAGCAAGGGCGAGGAGC) (SEQ ID NO: 79)
and 3' GFP+SaI (ACGCGTCGACTTACTTGTACAGCTCGTCCATG) (SEQ ID NO: 80)
with the GFP cDNA as template. The chimeric BTLA-GFP fusion cDNA
was amplified by PCR from a mixture of these two PCR fragments
using the primers J10RV1-BgIII and 3' GFP+SaI, digested with BgIII
and SaII, and cloned into the BgIII/SaII sites of IRES-GFP-RV to
produce DO11.10-BTLA-GFP-RV. A cytoplasmic deletion was made using
site directed mutagenesis (Stratagene) and the primers mj11 trunc
top (GTTGATATTCCAGTGAGCAAGGGCGAGGAG) (SEQ ID NO: 81) and mj11 trunc
bottom (CTTGCTCACTGGAATATCAACCAGGTTAGTG) (SEQ ID NO: 82) to produce
DO11.10-BTLA-trunc-GFP-RV. The C56BL/6 version of BTLA trunc-GFPRV
was made by purifying a natural BgIII/BamHI fragment from a BTLA
cDNA cloned from a mouse spleen cDNA phage library (Stratagene).
This fragment was then cloned into the Bg111/BamHI digested
DO11.10-BTLA trunc-GFP-RV to produce C57BL/6-BTLA trunc-GFP-RV.
[0729] Positive hybridomas were expanded and Abs purified using
MAPS II-protein A columns. Hamster monoclonal 6A6 is of the IgG
isotype, whereas all murine Abs are IgG1k. Unless otherwise stated,
all Abs were biotinylated using EZ-Link Sulfo-NHS-LC-biotin
(Pierce) and detected with SA-conjugated fluorochromes. This
procedure eliminated secondary Ab cross-reactivity with murine
cells.
Yeast Display Mapping
[0730] The Ig domain of the C57BL/6 BTLA allele was amplified from
cDNA using the primers 5'-GGAATTCCATATGCAGCCAAGTCCTGCCTG-3' (SEQ ID
NO: 83) and 5'-CATGCTAGCGAGAAAGCTACTAAGAGGAA-3' (SEQ ID NO: 84) and
subcloned into the NdeI and the NheI sites of the pCT302-AGA2d
vector to create an HA-tagged fusion to the Aga2 peptide.
QuickChange mutagenesis was used to introduce mutations into this
construct using the following primer pairs: C26At,
CAGTGCAACTTAATATTACGAGGAATTCCAAACAG (SEQ ID NO: 85); C26Ab,
CTCGTAATATTAAGTTGCACTGGACACTCTT (SEQ ID NO: 86); C32At,
GCAACTTACTATTAAGAGGAATTCCAAACAGTCTGC (SEQ ID NO: 87); C32Ab,
AATTCCTCTTAATAGTAAGTTGCACTGGACA (SEQ ID NO: 88); G48Ct,
GAATCCCAAACACTCTGCCAGGACAGGAGAGT (SEQ ID NO: 89); G48Cb,
CTGGCAGAGTGTTTGGAATTCCTCGTAATAG (SEQ ID NO: 90); A55Tt,
ACAGTCTGCCTGGACAGGAGAGTTATTTAAAATT (SEQ ID NO: 91); A55Tb,
TCCTGTCCAGGCAGACTGTTTTGAATTCCT (SEQ ID NO: 92); C79Gt,
GAGTTATTTAAAATTGAATGTCCTGTGAAATACTGTGT (SEQ ID NO: 93); C79 Gb,
AGGACATTCAATTTTAAATAACTCTCCTGTCC (SEQ ID NO: 94); T147Gt,
ATGGAACAATCTGGGTACCCCTTGAGGTTAGCC (SEQ ID NO: 95); T147 Gb,
GGGTACCCAGATTGTTCCATTGTGCTTAC (SEQ ID NO: 96); A163G/T168Gt,
TTGAGGTTGGCCCGCAGCTATACACTAG (SEQ ID NO: 97); A163/T168 Gb,
GCTGCGGGCCAACCTCAAGGGGTACACAGA (SEQ ID NO: 98); A197Gt,
TTGGGAAGAAAATCGATCAGTTCCGGTTTTTGTTCT (SEQ ID NO: 99); A197 Gb,
AACTGATCGATTTTCTTCCCAACTAGTGTA (SEQ ID NO: 100); C320Gt,
ATCCATGTGAGAGAAAGGACTCAAAACTCTTCA (SEQ ID NO: 101); and C320 Gb,
AGTCCTTTCTCTCACATGGATGGTTACTGAATG (SEQ ID NO: 102).
[0731] Transformation of EBY100.Aga1 yeast with each construct
resulted in surface expression of the BTLA mutant. Expression level
was confirmed by anti-HA staining. Yeast cells were stained with
anti-BTLA Abs as indicated to determine mutations that abolished Ab
recognition.
CD4+ T Cell Activation and Expression Analysis
[0732] DO11.10 TCR transgenic cells were activated with 0.3 .mu.M
OVA peptide (amino acids 323-339) and irradiated (2000 rad) BALB/c
splenic APCs as described. Th1 conditions consisted of heat-killed
Listeria monocytogenes, IL-2 (40 U/ml; Takeda Chemical Industries),
and 10 .mu.g/ml anti-IL-4 (11 B11). Th2 cells were differentiated
in 100 U/ml IL-4, 3 .mu.g/ml anti-IL-12 (TOSH), and IL-2. Cells
were restimulated with Ag and APCs on days 7 and 14. Th1/Th2
phenotypes were confirmed at days 7 and 14 by intracellular
cytokine staining for IFN-.gamma. and IL-4.
Gene Microarray
[0733] Anergic T cells were isolated by adoptively transferring
2.5.times.10.sup.6 Thy1.1+HA-specific T cells to recipient mice
(C3-HAhigh) as previously described. After 4 days in vivo, animals
were sacrificed via CO2 asphyxiation. Spleens were harvested, and
subjected to ACK lysis. Adoptively transferred HA-specific T cells
were enriched by binding the resulting cells with Abs to CD8a, B220
(RA3-6B2) and Thy1.2 (30-H12), followed by incubation with
SA-conjugated magnetic microbeads (Miltenyi Biotec). Unwanted cells
were depleted by passage over LS columns (Miltenyi Biotec)
according to the manufacturer's protocol. The remaining cells were
stained with an Ab to Thy1.1 (OX-7) and further enriched using
fluorescence-based cell sorting on a FACSVantage TurboSort (BD
Biosciences). The resulting populations were between 95 and 99%
pure. Cells were kept at 4.degree. C. throughout the enrichment
procedure. In vitro assays confirmed the anergic phenotype of the
sorted cells (data not shown). All Abs were purchased from BD
Pharmingen. This procedure specifically avoids ligation of the TCR
or CD4 during the isolation process. Activated, memory and naive
clonal T cells were isolated in an analogous manner, using a
specific viral construct (vaccinia-HA) to activate the cells after
adoptive transfer to nontransgenic B10.d2 mice. RNA was isolated
from each T cell population using the RNAeasy kit according to the
manufacturer's instructions (Qiagen), and cRNA probe was prepared.
Fragmented cRNA was hybridized to mouse GeneChips MU174A, MU174B,
and MU174C per Affymetrix standard hybridization protocol. Each
chip contained about 12,000 different genes (chip A) per expressed
sequence tag (EST) with (chips B and C), for a total of about
36,000 genes per EST from the three chips. A single gene/EST was
represented by a probe set defined by 16-20 perfect match
oligonucleotides that span the length of the gene, as well as 16
oligonucleotides with 1 by mismatch. The intensity of a gene was
determined by evaluating the perfect match and mismatch
intensities, as described in Affymetrix Microarray Suite, version
5.1 software (Affymetrix). The experiment was replicated once, for
a total of two replicate intensities within each condition. To
identify probe sets associated with an anergic phenotype, we used
the hypothesis-based analysis of microarrays algorithm as
previously described with the boolean hypothesis day 4 anergy
>naive AND day 4 anergy >day 4 activation.
Assessment of Anergy by Proliferation
[0734] On indicated days following transfer of HA-TCR transgenic T
cells, 20.times.10.sup.6 splenocytes were incubated with increasing
doses of HA peptide. Proliferation was assayed after 48 h, with a
[.sup.3H]thymidine pulse in the final 12 h.
BTLA Expression by Naive, Activated, and Anergic CD4+ T Cells
[0735] HA-TCR transgenic T cells were enriched by depletion of CD8+
and B220+ cells as earlier described. Cells were CFSE-labeled as
previously described before adoptive transfer of 2.5.times.10.sup.6
clonotypic cells via tail vein injection. Cells were stained with
anti-Thy1.1 PerCP and the anti-BTLA Ab 6F7-biotin, followed by
SA-PE.
Purification and Activation of CD44-CD25+ T Regulatory Cells
[0736] Splenocytes and lymph node cells from BALB/c mice were
isolated. Following erythrocyte lysis, B220+ cells were depleted by
magnetic separation with anti-B220 Microbeads (Miltenyi Biotec).
The negative fraction was stained with CD25-PE (BD Pharmingen) and
anti-PE Microbeads (Miltenyi Biotec) and magnetically separated
into CD25+ and CD25- fractions. Enrichment was assessed by FACS as
shown (see FIG. 46D). Contaminating non-CD4+ cells were mainly
B220+ or CD8+ cells. To activate T cells, 1.times.10.sup.6 cells/ml
of each fraction were cultured on flat-bottom plates coated with 10
.mu.g/m1 2C11 (anti-CD3; BD Pharmingen) for 48 h. Cells were pulse
with 1 .mu.Ci/well [.sup.3H]thymidine for an additional 12 h.
Ab Response to NP-Ficoll
[0737] Eight-week-old BTLA+/+ and BTLA-/- littermate mice on the
129SvEv background were immunized i.p. with 50 .mu.g of nitrophenyl
(NP)-Ficoll (Biosearch Technologies) in Imject alum (Pierce). Sera
were collected on day 14, and the titers of anti-NP were determined
by ELISA using NP25-BSA (Biosearch Technologies) for Ab capture and
the Southern Biotechnology clonotyping/HRP kit for IgG
subclass-specific ELISA (Southern Biotechnology Associates).
[0738] For further details regarding Example 14, including
references, see Hurchla et al., J. Immunol., 174: 3377-3385, 2005,
which is expressly incorporated herein in its entirety by
reference.
Example 15
BTLA-HVEM Effects in Graft Survival
BTLA and HVEM Regulate Acceptance of Partially MHC-Mismatched
Cardiac Allografts
[0739] Primarily vascularized cardiac allografts are the most
frequent organ transplant undertaken in mice and may be performed
across full MHC disparities, with rejection in 7-8 days, or across
MHC class I or II disparities, which leads to long-term survival
(>100 days). The basis for this unexpectedly long-term survival
of cardiac transplants across partial MHC disparities is unknown
and has received little attention. As anticipated from the
literature, we indeed found that cardiac allografts performed
across an MHC class II mismatch (Bm12 B6) survived long term in
wild-type recipients (mean survival time (MST), >100 days; n=6).
Histologic assessment of these allografts harvested at 2 wk after
transplant showed preservation of myocardial architecture and
generally only sparse mononuclear cell infiltration (FIG. 61A). In
contrast, BTLA-/- recipients rejected Bm 12 cardiac allografts by
2-3 wk after transplant (MST, 14.3.+-.3.8 days; n=12; p<0.001),
and histology showed a marked increase in leukocyte infiltration
and myocardial injury (FIG. 61A). In addition, comparable
abrogation of Bm12 allograft survival was seen with mAb targeting
of BTLA in wild-type recipients (MST, 23.2.+-.3.2; n=6; p<0.001)
or by engraftment of recipients lacking the BTLA ligand, HVEM (MST,
17.4.+-.4.2 days; n=8; p<0.001; FIG. 61A). Thus, BTLA and HVEM
are required to allow long-term survival of partially mismatched
cardiac allografts. In contrast to results obtained with BTLA-/-
recipients, PD-1-/- recipients receiving Bm12 cardiac allografts
exhibited an 80% long-term allograft survival (FIG. 61B), although
we did observe a minor role for PD-1 in regulating responses to
Bm12 cardiac allografts. Dual BTLA-/- and PD-1-/- knockout mice
(DKO) mice rejected Bm12 donor hearts more rapidly (MST, 10.5+1.5
days; n=4) than singly deficient BTLA-/- recipients (p<0.05) or
wild-type controls (p<0.0001; FIG. 61B).
[0740] Like MHC class II-mismatched grafts, MHC class I-mismatched
(Bm1 B6) cardiac allografts survived long term when transplanted to
wild-type B6 mice, but were rejected in BTLA-/- mice (FIG. 61C).
Furthermore, in contrast to wild-type B6 recipients, the MHC class
1-mismatched allografts in BTLA-/- recipients showed increased
mononuclear cell infiltration and progressive tissue damage
indicative of the development of cellular rejection (FIG. 61C).
PD-1-/- recipients receiving Bm1 cardiac allografts had 100%
long-term allograft survival (data not shown). Collectively, these
findings indicate that BTLA, in contrast to PD-1, is capable of
inhibiting the generation of a functional allogeneic immune
response in the context of partial MHC mismatches.
BTLA Suppresses MHC Class II-Dependent T Cell Responses
[0741] The unexpected rejection of Bm12 allografts by BTLA-/-, but
not PD-1-/-, mice suggested that BTLA and PD-1, or their ligands,
might be differentially expressed in partially MHC-mismatched
allografts. BTLA mRNA expression within Bm12 allografts was 20-fold
higher than PD-1 at 7 days after transplant, whereas no BTLA
expression was detected within Bm12 hearts engrafted into BTLA-/-
recipients, indicating BTLA expression primarily by infiltrating
host leukocytes (FIG. 62A). Comparable BTLA expression was observed
within long-surviving allografts (data not shown). Unlike BTLA,
only very low levels of PD-1 were detected in Bm12 allografts in
either wild-type or BTLA-/- recipients (FIG. 62A). No differences
in the levels of expression of HVEM, PD-L1, or PD-L2 were seen
between wild-type and BTLA-/- recipients (FIG. 62A). These data
suggest that in the Bm12 B6 model, BTLA is the predominant
inhibitory receptor expressed by infiltrating alloreactive T cells,
and that in the absence BTLA, there is no compensatory increase in
expression of additional inhibitory molecules.
[0742] We next studied the in vitro and in vivo responses of T
cells from wild-type and BTLA-/- mice to MHC class II Ags. First,
we examined the in vitro proliferation of purified wild-type or
BTLA-/- CD4+ T cells cocultured with irradiated Bm12 DC.
Proliferation of BTLA-/- T cells was increased compared with that
of wild-type T cells, as measured by either BrdU incorporation
(FIG. 62B) or CFSE dilution (FIG. 62C). To assess in vivo
responses, 40 million CFSE-labeled wild-type or BTLA-/- splenocytes
were adoptively transferred into irradiated Bm12 hosts, and donor
CD4+ T cell proliferation was assessed. Although a large portion of
wild-type CD4+ T cells remained undivided 72 h after adoptive
transfer, almost all BTLA-/- CD4+ T cells had entered the cycle and
proceeded through several rounds of division (FIG. 62D). Hence,
BTLA regulates CD4+ T cell alloactivation and proliferative
responses to MHC class II Ags.
[0743] MHC class II-restricted CD4+ T cell proliferation dominates
host alloresponses in the Bm12 B6 model, although host responses
are known to include stimulation of CD8+ precursor CTL by class
II-restricted CD4+ T cells. We found that although proliferative
responses of CD8+ T cells in irradiated Bm12 hosts were low
compared with those of CD4 cells, the alloactivation and
proliferation of CD8+ T cells from BTLA-/- mice were marginally
increased over control cells in this assay system (FIG. 62E). We
examined recipient anti-donor responder frequencies by ELISPOT,
with the readout of IFN-spot-forming cells by recipient
splenocytes. BTLA-/- recipient splenocytes had significantly higher
anti-donor responder frequencies when challenged with Bm12 APCs
(FIG. 62F), consistent with the increased allogeneic proliferation
in vitro and the accelerated graft rejection in vivo of T cells
from BTLA-/- mice.
Minor Role of BTLA in Fully MHC-Mismatched Alloresponses
[0744] We next tested whether BTLA played a similar dominant role
in regulating responses to fully MHC-mismatched cardiac allografts
as it did for partially MHC-mismatched cardiac allografts.
Wild-type recipients (B6, H-2b) rejected cardiac grafts (BALB/c,
H-2d) in 7-10 days (MST, 8.+-.1 days; n=6), whereas BTLA-/-
recipients showed a small and unexpected prolongation of graft
survival (MST, 12.+-.5 days; n=6; p<0.05; FIG. 63A). In
addition, wild-type mice treated with a neutralizing anti-BTLA mAb
showed a similar prolongation of allograft survival (MST, 13.+-.1
days; n=4; p<0.05) compared with control IgG treated recipients
(MST, 8+1 days; n=4; FIG. 63B). Furthermore, addition of a
subtherapeutic course of rapamycin prolonged graft survival in
wild-type mice by a few days (MST, 11.+-.2 days; n=6; p<0.05),
but significantly prolonged graft survival in BTLA-/- mice (MST,
53.+-.12 days; n=8; p<0.001), with 25% of the latter recipients
achieving long-term acceptance (FIG. 63C). Hence, in the case of
fully MHC-mismatched cardiac allografts, loss of BTLA did not
accelerate allograft rejection, but, rather, caused a surprising,
albeit small, increase in allograft survival. By contrast, the
presence or the absence of BTLA had no effect on the tempo of
rejection of B6 cardiac allografts by BALB/c recipients; all
allografts were rejected within 7-10 days (n=4/group;
p>0.05).
[0745] To understand the prolongation of fully MHC-mismatched graft
survival, we measured the expression of cytokines and chemokine
receptors important to host T cell recruitment in this model, using
allografts harvested 7 days after transplant. We found decreases in
IL-2 and IFN-mRNA in BTLA-/- recipients compared with wild-type
recipients (FIG. 63D). We also found reduced expression of CXCR3
and CCR5 in BTLA-/- recipients compared with wild-type recipients
(FIG. 63D). Therapy with rapamycin accentuated differences in
cytokine and chemokine receptor mRNA expression between BTLA-/- and
wild-type recipients (FIG. 63D). Given a key role for IFN-induced
IFN-inducible protein 10 (IP-10) production in promoting CXCR3+
cell recruitment and allograft rejection in this model, we
performed Western blotting, which confirmed that allografts in
BTLA-/- recipients had reduced IP-10 and CXCR3 proteins compared
with wild-type controls, with or without rapamycin therapy (FIG.
63E).
[0746] To assess whether the lack of BTLA affected the strong
alloactivation and proliferation induced in T cells by 72 h in this
model, we used the parent-to-F1 model involving transfer of
CFSE-labeled cells across fully allogeneic barriers (FIG. 63F). In
this model, the activation and cell cycle progression of CD4+
responses were similar for BTLA-/- and wild-type cells, and CD8+ T
cells from BTLA-/- mice were only marginally decreased compared
with those from wild-type controls (FIG. 63F). However, the
evaluation of intracellular cytokine production by alloreactive T
cells showed decreased IL-2 and IFN-production by alloreactive
BTLA-/- CD4+ and CD8+ T cells compared with wild-type T cells (FIG.
63G). Again, a subtherapeutic rapamycin dose caused a modest
decrease in proliferation of BTLA-/- T cells compared with
wild-type T cells, particularly CD8+ responses (FIG. 63F), and
decreased production of IL-2 and IFN-by both T cell subsets (FIG.
63G). These data indicate that T cell activation, proliferation,
and production of cytokines such as IL-2 and IFN-are decreased in
BTLA-/- mice, especially when recipients are treated with limited
immunosuppression, and that these impaired responses are associated
with modulation of chemokine/chemokine receptor effector
pathways.
Involvement of PD-1 and BTLA in Fully MHC-Mismatched
Alloresponses
[0747] In considering explanations for the differing effects of
BTLA in the partial MHC-mismatch and full MHC mismatch models, we
wondered whether differential reliance on PD-1 between these models
might play a role. Therefore, we examined the contributions of both
PD-1 and BTLA in the fully MHC-mismatched model (FIG. 64). We
found, first, that BALB/c cardiac allografts were rejected at
similar rates (p>0.05) by C57BL/6 wild-type mice and DKO mice
(FIG. 64A). Second, consistent with the DKO data, mAb blockade of
PD-1 increased the rate of rejection of fully MHC-mismatched
allografts by BTLA-/- recipients (p<0.001; FIG. 64B). Third, the
duration of allograft survival in BTLA-/- recipients receiving
subtherapeutic course of rapamycin (MST, 53.+-.12 days; n=8) was
markedly decreased by loss of PD-1, as seen by examining either DKO
recipients (MST, 12.8.+-.2.2 days; n=4; p<0.001; FIG. 64C) or by
mAb Ab blockade of PD-1 in BTLA-/- mice (MST, 14.0.+-.3.5 days;
n=4; p<0.001; FIG. 32D). In summary, in contrast to partial
MHC-mismatched allografts, the responses against fully
MHC-mismatched cardiac allografts are regulated by both BTLA and
PD-1.
[0748] We next asked whether PD-1 regulated the proliferation and
function of T cells responding to fully MHC-mismatched allografts.
Analysis by qPCR of BALB/c cardiac allografts harvested on day 7
after transplant from C57BL/6 recipients showed intragraft
expression of BTLA, PD-1, and their ligands, HVEM, PD-L1, and PD-L2
(FIG. 65A). By comparison with wild-type recipients, BALB/c
allografts harvested from BTLA-/- recipients had increased PD-1
expression (FIG. 65A; p<0.01). In contrast to PD-1 expression,
the expression of HVEM, PD-L1, and PD-L2 was not increased in
BTLA-/- recipients. These results suggest that in the absence of
BTLA, host leukocytes might express more PD-1 in response to
allostimulation.
[0749] To directly examine PD-1 expression by alloreactive
wild-type or BTLA-/- T cells, we adoptively transferred
CFSE-labeled splenocytes into irradiated Bm12 (class II-mismatched)
or B6D2F1 (fully MHC-mismatched) recipients. At analysis 72 h
later, we found that in the MHC class II partial mismatch, PD-1 was
weakly expressed by alloreactive CD4+ T cells, but not at all by
CD8+ T cells, from wild-type or BTLA-/- mice (FIG. 65B). In
contrast, with a full MHC mismatch, PD-1 expression by both CD4+
and CD8+ donor T cells was markedly increased, and the extent of
PD-1 expression was higher in BTLA-/- vs wild-type T cells (FIG.
65B). Moreover, treatment with rapamycin reduced PD-1 expression by
wild-type T cells, but had only minor effects on PD-1 induction by
T cells from BTLA-/- mice (FIG. 65B).
[0750] Lastly, we used in vivo and in vitro approaches to examine
the roles of BTLA and PD-1 in regulating T cell proliferation and
cytokine production in response to fully MHC-mismatched
allostimulation (FIG. 65, C-E). Compared with wild-type or BTLA-/-
cells, DKO cells showed enhanced proliferation (FIG. 65C) and Th1
cytokine production (FIG. 65D). Therapy with rapamycin decreased
the alloactivation-induced proliferation (FIG. 33C) and cytokine
production (FIG. 65E) of CD4+ and CD8+ T cells from wild-type and
BTLA-/- donors, but did not block these events in DKO CD4+ or CD8+
T cells (FIG. 65, C and E). Indeed, the production of IL-2 and
IFN-was increased in DKO T cells compared with wild-type and
BTLA-/- T cells (FIG. 65D), including in the presence of rapamycin
therapy (FIG. 65E). Collectively, these data indicate that 1) PD-1
expression is highly induced on the surfaces of alloreactive CD4+
and CD8+ T cells upon exposure to fully MHC-disparate allografts;
2) the levels of PD-1 on alloreactive CD4+ and CD8+ T cells are
still further increased in the absence of BTLA; and 3) increased
PD-1 expression is associated with inhibitory effects on the
alloantigen-induced production of cytokines such as IL-2 and IFN-.
In associated in vitro studies, as T cell activation increased in
response to allogeneic DC (FIG. 66), the induction of PD-1 was
increasingly apparent compared with that of BTLA. BTLA
up-regulation occurred upon T cell activation, but did not show
expansion comparable with that of PD-1 with increasing T cell
activation, suggesting that the strength of T cell activation
determines the relative importance of these two pathways.
Methods for Example 15
Mice
[0751] BTLA-/- b PD-1-/-, and dual BTLA-/- and PD-1-/- mice were
backcrossed for more than eight generations on a C57BL/6
background; HVEM-/- mice were generated by homologous recombination
and backcrossed more than five generations on a B6 background.
Wild-type C57BL/6 (H-2b), BALB/c (H-2d), C57BL6/DBA Fl (H-2b/d),
Bm12 (B6.C-H2bm12/KhEg), and Bml (B6.C--H2bml/ByJ) mice were
purchased from The Jackson Laboratory, housed in specific
pathogen-free conditions, and used for studies approved by the
institutional animal care and use committee of Children's Hospital
of Philadelphia.
[0752] An Armenian hamster anti-mBTLA neutralizing mAb, 6A6, was
described previously in Sedy et al. Nature Immunol. 6:90-98 (2005),
and we purchased mAbs for flow cytometry (BD Pharmingen) and Abs
for Western blotting (Santa Cruz Biotechnology). Labeling of cells
with CFSE (Molecular Probes) was undertaken as previously
reported.
Quantitative PCR (qPCR)
[0753] We performed qPCR as previously described. Briefly, RNA was
extracted with TRIzol (Invitrogen Life Technologies), RT of random
hexamers was performed with an ABI PRISM 5700 unit (Applied
Biosystems), and specific primer and probe sequences for target
genes were used for qPCR amplification of total cDNA (TaqMan PDAR;
Applied Biosystems). Relative quantitation of target cDNA was
determined using a control value of 1; the sample cDNA content was
expressed as the fold change from the control value. Differences in
cDNA input were corrected by normalizing signals obtained with
specific primers to ribosomal RNA; nonspecific amplification was
excluded by performing RT-PCRs without target cDNA.
Flow Cytometry
[0754] Alloreactive T cells were generated by i.v. injection of
40.times.10.sup.6 CFSE-labeled B6 spleen and lymph node cells into
B6/DBA Fl recipients, a parent Fl MHC mismatch in which only donor
cells respond. Splenocytes harvested after 3 days were incubated
with CD4-PE, CD8-PE, CD25-PE, CD44-PE, CD62L-PE, PD-1-PE, ICOS-PE,
and biotin-conjugated anti H-2 Kd and anti-H-2Dd mAb. Donor
alloreactive T cells were identified by gating on H-2 Kd and H-2Dd
cells (FACSCalibur; BD Biosciences), and their proliferation was
assessed by CFSE division profiles. For intracellular cytokine
staining, splenocytes (3.times.10.sup.6/ml) were treated with
Golgi-Stop (BD Pharmingen), stimulated for 4 h with PMA (3 ng/ml)
and ionomycin (1 .mu.M) in 24-well plates in complete medium (RPMI
1640, 10% FCS, 100 U/ml penicillin, 100 .mu.g/ml streptomycin, and
50 .mu.M 2-ME), and stained with cell surface markers (CD4-PE or
CD8-PE, biotin-conjugated H-2 Kd or H-2Dd, followed by
streptavidin-PerCP), fixed, and stained with IFN-allophycocyanin or
IL-2-allophycocyanin after permeabilization (Perm-Wash buffer; BD
Pharmingen).
In Vitro Cellular Assays
[0755] For propagation of bone marrow-derived DC, bone marrow cells
harvested from the femurs and tibia were cultured for 5-7 days in
24-well plates (2.times.10.sup.6/well) in medium plus mouse GM-CSF
(5 ng/ml) and IL-4 (10 ng/ml). One-way MLR cultures were performed
in triplicate, using magnetic column-eluted splenic T cells
(2.times.10.sup.5/well) as responders and gamma-irradiated (20 Gy)
DC as stimulators. Cultures were maintained in complete medium for
72-96 h, and T cell proliferation was determined by BrdU
incorporation or CFSE dilution profile. BrdU staining with a BrdU
labeling kit (BD Pharmingen) was performed using the manufacturer's
instructions. Cells were pulsed with BrdU, treated with
FcR-blocking CD16/CD32 mAbs, stained with cell surface markers,
fixed, permeabilized, treated with DNase/Triton X-100, stained with
anti-BrdII mAb, and analyzed by flow cytometry.
ELISPOT
[0756] Immunospot assays for IFN- were performed by coating ELISPOT
plates (BD Pharmingen) with anti-IFN-mAb, blocking, and addition of
responder cells isolated from cardiac transplant recipients plus
donor splenocytes or bone marrow-derived DC as stimulators;
recipient splenocytes or DC were used as syngeneic controls. At 24
h, cells were discarded, and wells were washed, followed by
biotinylated anti-IFN-mAb, streptavidin-HRP, and substrate. Spots
were counted using an Immunospot Analyzer (Cellular Technology),
and recipient anti-donor responder frequency was determined as the
number of IFN-spot-forming cells per-106 106 splenocytes.
Western Blots
[0757] Grafts were sonicated in lysis buffer containing Triton
X-100 and protease inhibitors, followed by centrifugation and assay
of supernatant protein content. Proteins were reduced, separated by
SDS-PAGE, and transferred to nitrocellulose membranes. Membranes
were blocked, incubated with primary and HRP-linked secondary Abs,
and, after the substrate reaction, analyzed using National
Institutes of Health Image.
Transplantation
[0758] Intra-abdominal vascularized cardiac allografting was
performed as previously described using 6- to 8-wk-old mice.
Briefly, donor ascending aorta and pulmonary artery were
anastomosed end-to-side to recipient infrarenal aorta and inferior
vena cava, respectively. Graft survival was assessed twice daily by
abdominal palpation; rejection was defined as total cessation of
cardiac contraction and was confirmed by histology.
Immunopathology
[0759] Portions of harvested allografts were fixed in formalin,
paraffin-embedded or snap-frozen, and analyzed by immunoperoxidase
staining with mAbs and an Envision kit (DakoCytomation).
Statistics
[0760] Allograft survival was used to generate Kaplan-Meier
survival curves, and comparison between groups was performed by
log-rank analysis.
[0761] For further details regarding Example 15, including
references, see Tao et al., J. Immunol., 175:5774-5782, 2005, which
is expressly incorporated herein in its entirety by reference.
Example 16
BTLA-HVEM Effects in Asthma
Regulated Expression of PD-1 and BTLA During Acute Allergic Airway
Inflammation
[0762] We first determined the kinetics of lymphocyte accumulation
and receptor expression in vivo by examining the cells recovered in
the bronchoalveolar lavage (BAL) fluid. Mice were systemically
sensitized and challenged with OVA. At 1, 3, 4, or 7 days following
challenge groups of mice were euthanized and BAL performed. On 1
day following challenge, few CD4+ T cells were found in the BAL
fluid. Significantly increased numbers of CD4 T cells appeared by
day 3 which peaked by day 7 post-challenge (FIG. 57). We next
examined the expression of PD-1 and BTLA on CD4 T cells recovered
in the BAL fluid. Consistent with previous reports that PD-1
expression is induced on activated cells, we found that PD-1
expression gradually increased, being detectable on day 3 and
reaching its maximum on day 7 following challenge. BTLA expression
exhibited a reciprocal pattern with expression being greatest on
day 3 and nearly undetectable by day 7 (FIG. 57).
[0763] Given the distinct patterns of expression of these receptors
on BAL T cells, we next examined the phenotype of mice deficient
either BTLA or PD-1 in the acute allergic airway inflammation model
(FIG. 58). Both BTLA-deficient and PD-1-deficient mice showed some
increase in inflammatory cell recruitment compared to wild type
mice (FIGS. 58A and B). All genotypes had a mixed inflammatory cell
infiltrate, although there was an increased percentage of
neutrophils and eosinophils in the BTLA-deficient mice (FIGS. 58A
and B). Examination of the lung tissues revealed a mild increase in
the intensity of inflammatory infiltrates in PD-1 and
BTLA-deficient animals compared to wild type controls. Thus, while
PD-1 and BTLA have been reported as being potent inhibitory
receptors, we found only a relatively mild increase in the
inflammatory response following of acute allergic airway
inflammation in the absence of either of these inhibitory
receptors.
Delayed Expression of Ligands for BTLA and PD-1 in Acute Allergic
Airway Inflammation
[0764] Given the documented inhibitory activity of BTLA and PD-1 in
vivo, we were surprised that the absence of either of these
receptors did not have a greater effect on acute airway
inflammation. We therefore speculated that the ligands for these
receptors might not be expressed thereby not allowing this axis of
regulation to be apparent. We examined the expression of mRNA for
Herpes Virus Entry Mediator (HVEM), the ligand for BTLA, and PD-L1
and PD-L2, the ligands for PD-1, during an extended time course of
airway inflammation (FIG. 59). Expression of HVEM message was
nearly undetectable in the first four days of acute allergic airway
inflammation following challenge but became apparent by day 7 and
was maximal by day 10 and 15 (FIG. 57, upper panels). Likewise, the
expression of PD-L1 was first detectable at day 2, but remained
relatively low in expression until approximately day 7 to day 10.
Expression of PD-L2, a second ligand for PD-1, was maximum at day 4
following intranasal challenge, and declined subsequently.
Interestingly, both HVEM and PDL1 were detectable in RNA samples
obtained from cultured murine tracheal epithelial cells (mTEC),
suggesting that the source of ligand may be non-immune cells of the
lung.
BTLA and PD-0.1 Limit the Duration of Acute Allergic Airway
Inflammation
[0765] Because the ligands for PD-1 and BTLA were maximally
expressed in the second week following intranasal challenge, we
next examined BAL cell numbers and compositions at day 10 and day
15 following intranasal challenge (FIG. 60). Wild type mice had
completely resolved the inflammation, as evidenced by a low number
of cells recovered in the BAL fluid and histology at days 10 and 15
following challenge. In stark contrast, mice deficient in BTLA and
PD-1 showed a persistent increase in BAL cells on day 10 following
intranasal challenge. Furthermore, the composition of these cells
in this fluid revealed a greater proportion of lymphocytes and
eosinophils in comparison to the few cells in the wild type mice,
which consisted predominantly of macrophages. Even on day 15,
examination of BTLA-deficient mice revealed the continued presence
increased numbers of lymphocytes and eosinophils: Direct
histological examination of H and E stained sections also
demonstrated persistent inflammation in the lungs of both PD-1 and
BTLA-deficient mice at days 10 and 15, whereas the wild type mice
had complete resolution in this time frame. Thus, these receptors
are critical for the normal resolution of airway inflammation.
[0766] T cell dependent immune responses are determined by the
coordinate integration of signals derived from both cell:cell
interactions and soluble mediators. We have recently described a
novel role for CD28 signaling not only in the early priming phase
but also in maintenance of the effector phase of allergic airway
inflammation. These studies focused on an acute model, acting
between days 1 and 3. By contrast, the present results show that
the inhibitory receptors BTLA and PD-1 exert a slight effect in
attenuating the degree of acute inflammation but have a profound
effect on the duration of inflammation, suggesting they act to
terminate the immune response. We also observed a temporal
regulation of expression of the ligands for these receptors during
the course of the inflammatory response. Therefore, these data
support that the regulated expression of inhibitory receptors on
lymphocytes and their ligands in the lung are critical for the
proper termination of the acute inflammatory response. In the
absence of the inhibitory receptors on lymphocytes, the normally
self limited acute inflammatory response progresses to a chronic
infiltrate that persists for at least 15 days. We propose, based on
these findings, that abnormalities in this axis could play a role
in pathologic situations such as chronic persistent asthma and may
represent novel targets for therapeutic intervention.
Methods for Example 16
Mice
[0767] BTLA-deficient mice were generated as previously described.
PD-1 deficient mice were obtained from Tasuka Honjo (Kyoto
University, Kyoto Japan). C57BL/6 mice were purchased from Jackson
Laboratories (Bar Harbor, Me.). All mice were housed in specific
pathogen free facilities at Washington University School of
Medicine. All animal studies have been approved by the Washington
University Animal Studies Committee.
Antibodies
[0768] Anti-BTLA antibody (Clone 6F7, mouse IgG1) was generated as
previously described. Anti-PD-1 and anti-CD4 antibodies were
purchased from Ebiosciences. Flow cytometric analysis was performed
on a FacsCalibur cytometer using Cellquest software (Becton
Dickinson Corporation). Analysis was performed using FloJo
software.
RT-PCR
[0769] Total RNA was extracted from lung tissue of control or
allergen challenged mice using Trizol (Invitrogen). Random primed
cDNA was prepared using the Retroscript kit (Ambion). Specific
primers for PDL1, PDL2 and HVEM were designed that spanned intronic
sequences. Control primers amplify ribosomal S15 RNA and are
provided with the Retroscript Kit.
Experimental Allergic Airway Inflammation
[0770] Mice were sensitized and challenged with Ovalbumin as
previously described. Briefly, mice were injected i.p. with Ova
adsorbed to alum on days 0 and 7. On day 14 they received an
intranasal challenge of 50 pi of 1% Ova in the morning and
afternoon. Samples were collected as previously described on the
indicated days following inhaled challenge.
[0771] Preparation of murine tracheal epithelial cells: Primary
mouse airway epithelial cells were cultured and differentiated
using an established high fidelity model of the mouse airway.
Briefly, epithelial cells were harvested from mouse tracheas of
C57/BI6 strain mice (5-6 weeks old) using pronase digestion. Cells
were purified by differential adherence of fibroblasts to yield a
preparation composed of greater than 99% epithelial cells
determined by expression of cytokeratin. Mouse tracheal epithelial
cells (MTEC) were cultured in the presence of growth factor
supplemented media on semi-permeable membranes (Transwell,
Corning-Costar, Corning, N.Y.). Media was maintained in upper and
lower chambers until the transmembrane resistance was greater than
1,000 Ohmscm2 indicating tight junction formation. Media was then
removed from the upper chamber to establish an air-liquid interface
(ALI) condition used for epithelial cell differentiation. Cells
were differentiated for at least 7 days at ALI to generate a
multilayer model of the airway composed of ciliated, secretory, and
basal airway epithelial cells. RNA was prepared from day 7 ALI
cultures using Trizol reagent.
Example 17
Effect of BTLA Loss of Function on Humoral Response
[0772] We immunized cohorts of mice with one injection of NP-Ficoll
in alum and measured production of anti-NP antibodies of specific
isotypes on day 14. For the isotypes IgM, IgG1, IgA, we found no
specific changes in levels of anti-NP antibodies. For IgG2a or
IgG2b, we found only slight increases in anti-NP antibodies in the
BTLA-/- compared to wild type mice. However, for antibodies of the
IgG3 isotype, which is primarily associated with T-independent
responses, we found approximately a two-fold increased in anti-NP
specific antibodies in BTLA-/- mice compared to wild type mice.
[0773] In addition, spontaneous germinal centers have been observed
at a higher frequency than control in aging BTLA -/- mice.
Example 18
BTLA Modulates Response to Viral Infection
[0774] Wildtype and BTLA knockout mice were infected with Sendai
virus and monitored for three weeks. BTLA knockout mice maintained
higher body weight and exhibited greater survival following
infection with Sendai virus. Similar results were obtained using
West Nile virus.
Sequence CWU 1
1
621283PRTMus musculus 1Met Ala Ser Leu Gly Gln Ile Ile Phe Trp Ser
Ile Ile Asn Ile Ile1 5 10 15Ile Ile Leu Ala Gly Ala Ile Ala Leu Ile
Ile Gly Phe Gly Ile Ser 20 25 30Gly Lys His Phe Ile Thr Val Thr Thr
Phe Thr Ser Ala Gly Asn Ile 35 40 45Gly Glu Asp Gly Thr Leu Ser Cys
Thr Phe Glu Pro Asp Ile Lys Leu 50 55 60Asn Gly Ile Val Ile Gln Trp
Leu Lys Glu Gly Ile Lys Gly Leu Val65 70 75 80His Glu Phe Lys Glu
Gly Lys Asp Asp Leu Ser Gln Gln His Glu Met 85 90 95Phe Arg Gly Arg
Thr Ala Val Phe Ala Asp Gln Val Val Val Gly Asn 100 105 110Ala Ser
Leu Arg Leu Lys Asn Val Gln Leu Thr Asp Ala Gly Thr Tyr 115 120
125Thr Cys Tyr Ile Arg Thr Ser Lys Gly Lys Gly Asn Ala Asn Leu Glu
130 135 140Tyr Lys Thr Gly Ala Phe Ser Met Pro Glu Ile Asn Val Asp
Tyr Asn145 150 155 160Ala Ser Ser Glu Ser Leu Arg Cys Glu Ala Pro
Arg Trp Phe Pro Gln 165 170 175Pro Thr Val Ala Trp Ala Ser Gln Val
Asp Gln Gly Ala Asn Phe Ser 180 185 190Glu Val Ser Asn Thr Ser Phe
Glu Leu Asn Ser Glu Asn Val Thr Met 195 200 205Lys Val Val Ser Val
Leu Tyr Asn Val Thr Ile Asn Asn Thr Tyr Ser 210 215 220Cys Met Ile
Glu Asn Asp Ile Ala Lys Ala Thr Gly Asp Ile Lys Val225 230 235
240Thr Asp Ser Glu Val Lys Arg Arg Ser Gln Leu Gln Leu Leu Asn Ser
245 250 255Gly Pro Ser Pro Cys Val Phe Ser Ser Ala Phe Ala Ala Gly
Trp Ala 260 265 270Leu Leu Ser Leu Ser Cys Cys Leu Met Leu Arg 275
2802282PRTHomo sapiens 2Met Ala Ser Leu Gly Gln Ile Leu Phe Trp Ser
Ile Ile Ser Ile Ile1 5 10 15Ile Ile Leu Ala Gly Ala Ile Ala Leu Ile
Ile Gly Phe Gly Ile Ser 20 25 30Gly Arg His Ser Ile Thr Val Thr Thr
Val Ala Ser Ala Gly Asn Ile 35 40 45Gly Glu Asp Gly Ile Leu Ser Cys
Thr Phe Glu Pro Asp Ile Lys Leu 50 55 60Ser Asp Ile Val Ile Gln Trp
Leu Lys Glu Gly Val Leu Gly Leu Val65 70 75 80His Glu Phe Lys Glu
Gly Lys Asp Glu Leu Ser Glu Gln Asp Glu Met 85 90 95Phe Arg Gly Arg
Thr Ala Val Phe Ala Asp Gln Val Ile Val Gly Asn 100 105 110Ala Ser
Leu Arg Leu Lys Asn Val Gln Leu Thr Asp Ala Gly Thr Tyr 115 120
125Lys Cys Tyr Ile Ile Thr Ser Lys Gly Lys Gly Asn Ala Asn Leu Glu
130 135 140Tyr Lys Thr Gly Ala Phe Ser Met Pro Glu Val Asn Val Asp
Tyr Asn145 150 155 160Ala Ser Ser Glu Thr Leu Arg Cys Glu Ala Pro
Arg Trp Phe Pro Gln 165 170 175Pro Thr Val Val Trp Ala Ser Gln Val
Asp Gln Gly Ala Asn Phe Ser 180 185 190Glu Val Ser Asn Thr Ser Phe
Glu Leu Asn Ser Glu Asn Val Thr Met 195 200 205Lys Val Val Ser Val
Leu Tyr Asn Val Thr Ile Asn Asn Thr Tyr Ser 210 215 220Cys Met Ile
Glu Asn Asp Ile Ala Lys Ala Thr Gly Asp Ile Lys Val225 230 235
240Thr Glu Ser Glu Ile Lys Arg Arg Ser His Leu Gln Leu Leu Asn Ser
245 250 255Lys Ala Ser Leu Cys Val Ser Ser Phe Phe Ala Ile Ser Trp
Ala Leu 260 265 270Leu Pro Leu Ser Pro Tyr Leu Met Leu Lys 275
2803852DNAMus musculus 3atggcttcct tggggcagat catcttttgg agtattatta
acatcatcat catcctggct 60ggggccatcg cactcatcat tggctttggc atttcaggca
agcacttcat cacggtcacg 120accttcacct cagctggaaa cattggagag
gacgggaccc tgagctgcac ttttgaacct 180gacatcaaac tcaacggcat
cgtcatccag tggctgaaag aaggcatcaa aggtttggtc 240cacgagttca
aagaaggcaa agacgacctc tcacagcagc atgagatgtt cagaggccgc
300acagcagtgt ttgctgatca ggtggtagtt ggcaatgctt ccctgagact
gaaaaacgtg 360cagctcacgg atgctggcac ctacacatgt tacatccgca
cctcaaaagg caaagggaat 420gcaaacctag agtataagac cggagccttc
agtatgccag agataaatgt ggactataat 480gccagttcag agagtttacg
ctgcgaggct cctcggtggt tcccccagcc cacagtggcc 540tgggcatctc
aagtcgacca aggagccaac ttctcagaag tctcgaacac cagctttgag
600ttgaactctg agaatgtgac catgaaggtc gtatctgtgc tctacaatgt
cacaatcaac 660aacacatact cctgtatgat tgaaaatgac attgccaaag
ccactgggga catcaaagtg 720acagattcag aggtcaaaag gcggagtcag
ctgcagctgc tcaactccgg gccttccccg 780tgtgtttttt cttctgcctt
tgcggctggc tgggcgctcc tatctctctc ctgttgcctg 840atgctaagat ga
8524849DNAHomo sapiens 4atggcttccc tggggcagat cctcttctgg agcataatta
gcatcatcat tattctggct 60ggagcaattg cactcatcat tggctttggt atttcaggga
gacactccat cacagtcact 120actgtcgcct cagctgggaa cattggggag
gatggaatcc tgagctgcac ttttgaacct 180gacatcaaac tttctgatat
cgtgatacaa tggctgaagg aaggtgtttt aggcttggtc 240catgagttca
aagaaggcaa agatgagctg tcggagcagg atgaaatgtt cagaggccgg
300acagcagtgt ttgctgatca agtgatagtt ggcaatgcct ctttgcggct
gaaaaacgtg 360caactcacag atgctggcac ctacaaatgt tatatcatca
cttctaaagg caaggggaat 420gctaaccttg agtataaaac tggagccttc
agcatgccgg aagtgaatgt ggactataat 480gccagctcag agaccttgcg
gtgtgaggct ccccgatggt tcccccagcc cacagtggtc 540tgggcatccc
aagttgacca gggagccaac ttctcggaag tctccaatac cagctttgag
600ctgaactctg agaatgtgac catgaaggtt gtgtctgtgc tctacaatgt
tacgatcaac 660aacacatact cctgtatgat tgaaaatgac attgccaaag
caacagggga tatcaaagtg 720acagaatcgg agatcaaaag gcggagtcac
ctacagctgc taaactcaaa ggcttctctg 780tgtgtctctt ctttctttgc
catcagctgg gcacttctgc ctctcagccc ttacctgatg 840ctaaaataa
8495306PRTMus musculus 5Met Lys Thr Val Pro Ala Met Leu Gly Thr Pro
Arg Leu Phe Arg Glu1 5 10 15Phe Phe Ile Leu His Leu Gly Leu Trp Ser
Ile Leu Cys Glu Lys Ala 20 25 30Thr Lys Arg Asn Asp Glu Glu Cys Glu
Val Gln Leu Asn Ile Lys Arg 35 40 45Asn Ser Lys His Ser Ala Trp Thr
Gly Glu Leu Phe Lys Ile Glu Cys 50 55 60Pro Val Lys Tyr Cys Val His
Arg Pro Asn Val Thr Trp Cys Lys His65 70 75 80Asn Gly Thr Ile Trp
Val Pro Leu Glu Val Gly Pro Gln Leu Tyr Thr 85 90 95Ser Trp Glu Glu
Asn Arg Ser Val Pro Val Phe Val Leu His Phe Lys 100 105 110Pro Ile
His Leu Ser Asp Asn Gly Ser Tyr Ser Cys Ser Thr Asn Phe 115 120
125Asn Ser Gln Val Ile Asn Ser His Ser Val Thr Ile His Val Arg Glu
130 135 140Arg Thr Gln Asn Ser Ser Glu His Pro Leu Ile Thr Val Ser
Asp Ile145 150 155 160Pro Asp Ala Thr Asn Ala Ser Gly Pro Ser Thr
Met Glu Glu Arg Pro 165 170 175Gly Arg Thr Trp Leu Leu Tyr Thr Leu
Leu Pro Leu Gly Ala Leu Leu 180 185 190Leu Leu Leu Ala Cys Val Cys
Leu Leu Cys Phe Leu Lys Arg Ile Gln 195 200 205Gly Lys Glu Lys Lys
Pro Ser Asp Leu Ala Gly Arg Asp Thr Asn Leu 210 215 220Val Asp Ile
Pro Ala Ser Ser Arg Thr Asn His Gln Ala Leu Pro Ser225 230 235
240Gly Thr Gly Ile Tyr Asp Asn Asp Pro Trp Ser Ser Met Gln Asp Glu
245 250 255Ser Glu Leu Thr Ile Ser Leu Gln Ser Glu Arg Asn Asn Gln
Gly Ile 260 265 270Val Tyr Ala Ser Leu Asn His Cys Val Ile Gly Arg
Asn Pro Arg Gln 275 280 285Glu Asn Asn Met Gln Glu Ala Pro Thr Glu
Tyr Ala Ser Ile Cys Val 290 295 300Arg Ser3056289PRTHomo sapiens
6Met Lys Thr Leu Pro Ala Met Leu Gly Thr Gly Lys Leu Phe Trp Val1 5
10 15Phe Phe Leu Ile Pro Tyr Leu Asp Ile Trp Asn Ile His Gly Lys
Glu 20 25 30Ser Cys Asp Val Gln Leu Tyr Ile Lys Arg Gln Ser Glu His
Ser Ile 35 40 45Leu Ala Gly Asp Pro Phe Glu Leu Glu Cys Pro Val Lys
Tyr Cys Ala 50 55 60Asn Arg Pro His Val Thr Trp Cys Lys Leu Asn Gly
Thr Thr Cys Val65 70 75 80Lys Leu Glu Asp Arg Gln Thr Ser Trp Lys
Glu Glu Lys Asn Ile Ser 85 90 95Phe Phe Ile Leu His Phe Glu Pro Val
Leu Pro Asn Asp Asn Gly Ser 100 105 110Tyr Arg Cys Ser Ala Asn Phe
Gln Ser Asn Leu Ile Glu Ser His Ser 115 120 125Thr Thr Leu Tyr Val
Thr Asp Val Lys Ser Ala Ser Glu Arg Pro Ser 130 135 140Lys Asp Glu
Met Ala Ser Arg Pro Trp Leu Leu Tyr Ser Leu Leu Pro145 150 155
160Leu Gly Gly Leu Pro Leu Leu Ile Thr Thr Cys Phe Cys Leu Phe Cys
165 170 175Cys Leu Arg Arg His Gln Gly Lys Gln Asn Glu Leu Ser Asp
Thr Ala 180 185 190Gly Arg Glu Ile Asn Leu Val Asp Ala His Leu Lys
Ser Glu Gln Thr 195 200 205Glu Ala Ser Thr Arg Gln Asn Ser Gln Val
Leu Leu Ser Glu Thr Gly 210 215 220Ile Tyr Asp Asn Asp Pro Asp Leu
Cys Phe Arg Met Gln Glu Gly Ser225 230 235 240Glu Val Tyr Ser Asn
Pro Cys Leu Glu Glu Asn Lys Pro Gly Ile Val 245 250 255Tyr Ala Ser
Leu Asn His Ser Val Ile Gly Leu Asn Ser Arg Leu Ala 260 265 270Arg
Asn Val Lys Glu Ala Pro Thr Glu Tyr Ala Ser Ile Cys Val Arg 275 280
285Ser7870DNAHomo sapiens 7atgaagacat tgcctgccat gcttggaact
gggaaattat tttgggtctt cttcttaatc 60ccatatctgg acatctggaa catccatggg
aaagaatcat gtgatgtaca gctttatata 120aagagacaat ctgaacactc
catcttagca ggagatccct ttgaactaga atgccctgtg 180aaatactgtg
ctaacaggcc tcatgtgact tggtgcaagc tcaatggaac aacatgtgta
240aaacttgaag atagacaaac aagttggaag gaagagaaga acatttcatt
tttcattcta 300cattttgaac caatgcttcc taatgacaat gggtcatacc
gctgttctgc aaattttcag 360tctaatctca ttgaaagcca ctcaacaact
ctttatgtga cagatgtaaa aggtgcctca 420gaacgaccct ccaaggacga
agtggcaagc agaccctggc tcctgtatag tttacttcct 480ttggggggat
tgcctctact catcactacc tggttctgcc tgttctgctg cctgagaagg
540caccaaggaa agcaaaatga actctctgac acagcaggaa gggaaattaa
tctggttgat 600gctcacctta agagcgagca aacagaagca agcaccaggc
aaaattccca agtactgcta 660tcagaagctg gaatttatga taatgaccct
gacctttgtt tcaggatgca ggaagggtct 720gaagtttgtt ctaatccatg
cctggaagaa aacaaaccag gcattgttta tgcttccctg 780aaccattctg
tcattggact gaactcaaga ctggcaagaa atgtaaaaga agcaccaaca
840gaatatgcat ccatatgtgt gaggagttaa 8708289PRTHomo sapiens 8Met Lys
Thr Leu Pro Ala Met Leu Gly Thr Gly Lys Leu Phe Trp Val1 5 10 15Phe
Phe Leu Ile Pro Tyr Leu Asp Ile Trp Asn Ile His Gly Lys Glu 20 25
30Ser Cys Asp Val Gln Leu Tyr Ile Lys Arg Gln Ser Glu His Ser Ile
35 40 45Leu Ala Gly Asp Pro Phe Glu Leu Glu Cys Pro Val Lys Tyr Cys
Ala 50 55 60Asn Arg Pro His Val Thr Trp Cys Lys Leu Asn Gly Thr Thr
Cys Val65 70 75 80Lys Leu Glu Asp Arg Gln Thr Ser Trp Lys Glu Glu
Lys Asn Ile Ser 85 90 95Phe Phe Ile Leu His Phe Glu Pro Met Leu Pro
Asn Asp Asn Gly Ser 100 105 110Tyr Arg Cys Ser Ala Asn Phe Gln Ser
Asn Leu Ile Glu Ser His Ser 115 120 125Thr Thr Leu Tyr Val Thr Asp
Val Lys Gly Ala Ser Glu Arg Pro Ser 130 135 140Lys Asp Glu Val Ala
Ser Arg Pro Trp Leu Leu Tyr Ser Leu Leu Pro145 150 155 160Leu Gly
Gly Leu Pro Leu Leu Ile Thr Thr Trp Phe Cys Leu Phe Cys 165 170
175Cys Leu Arg Arg His Gln Gly Lys Gln Asn Glu Leu Ser Asp Thr Ala
180 185 190Gly Arg Glu Ile Asn Leu Val Asp Ala His Leu Lys Ser Glu
Gln Thr 195 200 205Glu Ala Ser Thr Arg Gln Asn Ser Gln Val Leu Leu
Ser Glu Ala Gly 210 215 220Ile Tyr Asp Asn Asp Pro Asp Leu Cys Phe
Arg Met Gln Glu Gly Ser225 230 235 240Glu Val Cys Ser Asn Pro Cys
Leu Glu Glu Asn Lys Pro Gly Ile Val 245 250 255Tyr Ala Ser Leu Asn
His Ser Val Ile Gly Leu Asn Ser Arg Leu Ala 260 265 270Arg Asn Val
Lys Glu Ala Pro Thr Glu Tyr Ala Ser Ile Cys Val Arg 275 280
285Ser9921DNAMus musculus 9atgaagacag tgcctgccat gcttgggact
cctcggttat ttagggaatt cttcatcctc 60catctgggcc tctggagcat cctttgtgag
aaagctacta agaggaatga tgaagagtgt 120gaagtgcaac ttaatattaa
gaggaattcc aaacactctg cctggacagg agagttattt 180aaaattgaat
gtcctgtgaa atactgtgtt catagaccta atgtgacttg gtgtaagcac
240aatggaacaa tctgggtacc ccttgaagtt ggtcctcagc tatacactag
ttgggaagaa 300aatcgatcag ttccggtttt tgttctccat tttaaaccaa
tacatctcag tgataacggg 360tcgtatagct gttctacaaa cttcaattct
caagttatta atagccattc agtaaccatc 420catgtgagag aaaggactca
aaactcttca gaacacccac taataacagt atctgacatc 480ccagatgcca
ccaatgcctc aggaccatcc accatggaag agaggccagg caggacttgg
540ctgctttaca ccttgcttcc tttgggggca ttgcttctgc tccttgcctg
tgtctgcctg 600ctctgctttc tgaaaaggat ccaagggaaa gaaaagaagc
cttctgactt ggcaggaagg 660gacactaacc tggttgatat tccagccagt
tccaggacaa atcaccaagc actgccatca 720ggaactggaa tttatgataa
tgatccctgg tctagcatgc aggatgaatc tgaattgaca 780attagcttgc
aatcagagag aaacaaccag ggcattgttt atgcttcttt gaaccattgt
840gttattggaa ggaatccaag acaggaaaac aacatgcagg aggcacccac
agaatatgca 900tccatttgtg tgagaagtta a 92110306PRTMus musculus 10Met
Lys Thr Val Pro Ala Met Leu Gly Thr Pro Arg Leu Phe Arg Glu1 5 10
15Phe Phe Ile Leu His Leu Gly Leu Trp Ser Ile Leu Cys Glu Lys Ala
20 25 30Thr Lys Arg Asn Asp Glu Glu Cys Glu Val Gln Leu Asn Ile Lys
Arg 35 40 45Asn Ser Lys His Ser Ala Trp Thr Gly Glu Leu Phe Lys Ile
Glu Cys 50 55 60Pro Val Lys Tyr Cys Val His Arg Pro Asn Val Thr Trp
Cys Lys His65 70 75 80Asn Gly Thr Ile Trp Val Pro Leu Glu Val Gly
Pro Gln Leu Tyr Thr 85 90 95Ser Trp Glu Glu Asn Arg Ser Val Pro Val
Phe Val Leu His Phe Lys 100 105 110Pro Ile His Leu Ser Asp Asn Gly
Ser Tyr Ser Cys Ser Thr Asn Phe 115 120 125Asn Ser Gln Val Ile Asn
Ser His Ser Val Thr Ile His Val Arg Glu 130 135 140Arg Thr Gln Asn
Ser Ser Glu His Pro Leu Ile Thr Val Ser Asp Ile145 150 155 160Pro
Asp Ala Thr Asn Ala Ser Gly Pro Ser Thr Met Glu Glu Arg Pro 165 170
175Gly Arg Thr Trp Leu Leu Tyr Thr Leu Leu Pro Leu Gly Ala Leu Leu
180 185 190Leu Leu Leu Ala Cys Val Cys Leu Leu Cys Phe Leu Lys Arg
Ile Gln 195 200 205Gly Lys Glu Lys Lys Pro Ser Asp Leu Ala Gly Arg
Asp Thr Asn Leu 210 215 220Val Asp Ile Pro Ala Ser Ser Arg Thr Asn
His Gln Ala Leu Pro Ser225 230 235 240Gly Thr Gly Ile Tyr Asp Asn
Asp Pro Trp Ser Ser Met Gln Asp Glu 245 250 255Ser Glu Leu Thr Ile
Ser Leu Gln Ser Glu Arg Asn Asn Gln Gly Ile 260 265 270Val Tyr Ala
Ser Leu Asn His Cys Val Ile Gly Arg Asn Pro Arg Gln 275 280 285Glu
Asn Asn Met Gln Glu Ala Pro Thr Glu Tyr Ala Ser Ile Cys Val 290 295
300Arg Ser30511322DNAMus musculus 11gatgaagagt gtgaagtgca
acttaatatt aagaggaatt ccaaacactc tgcctggaca 60ggagagttat ttaaaattga
atgtcctgtg aaatactgtg ttcatagacc taatgtgact 120tggtgtaagc
acaatggaac aatctgggta ccccttgaag ttggtcctca gctatacact
180agttgggaag aaaatcgatc agttccggtt tttgttctcc attttaaacc
aatacatctc 240agtgataacg ggtcgtatag ctgttctaca aacttcaatt
ctcaagttat taatagccat 300tcagtaacca tccatgtgag ag 32212322DNAMus
musculus 12gatgaagagt gtgaagtgca acttaatatt aagaggaatt ccaaacactc
tgcctggaca 60ggagagttat ttaaaattga atgtcctgtg aaatactgtg ttcatagacc
tcatgtgact 120tggtgtaagc acaatggaac aatctgggta ccccttgaag
ttggtcctca gctatacact 180agttgggaag aaaatcgatc
agttccggtt tttgttctcc attttaaacc aatacatctc 240agtgataacg
ggtcgtatag ctgttctaca aacttcaatt ctcaagttat taatagccat
300tcagtaacca tccatgtgag ag 32213300DNAMus musculus 13gatgaagagt
gtccagtgca acttactatt acgaggaatt ccaaacagtc tgccaggaca 60ggagagttat
ttaaaattca atgtcctgtg aaatactgtg ttcatagacc taatgtgact
120tggtgtaagc acaatggaac aatctgtgta ccccttgagg ttagccctca
gctatacact 180agttgggaag aaaatcaatc agttccggtt tttgttctcc
actttaaacc aatacatctc 240agtgataatg ggtcgtatag ctgttctaca
aacttcaatt ctcaagttat taatagccat 30014322DNAMus musculus
14gatgaagagt gtgaagtgca acttaatatt aagaggaatt ccaaacactc tgcctggaca
60ggagagttat ttaaaattga atgtcctgtg aaatactgtg ttcatagacc taatgtgact
120tggtgtaagc acaatggaac aatctgggta ccccttgaag ttggtcctca
gctatacact 180agttgggaag aaaatcgatc agttccggtt tttgttctcc
attttaaacc aatacatctc 240agtgataacg ggtcgtatag ctgttctaca
aacttcaatt ctcaagttat taatagccat 300tcagtaacca tccatgtgag ag
32215322DNAMus musculus 15gatgaagagt gtgaagtgca acttaatatt
aagaggaatt ccaaacactc tgcctggaca 60ggagagttat ttaaaattga atgtcctgtg
aaatactgtg ttcatagacc tcatgtgact 120tggtgtaagc acaatggaac
aatctgggta ccccttgaag ttggtcctca gctatacact 180agttgggaag
aaaatcgatc agttccggtt tttgttctcc attttaaacc aatacatctc
240agtgataacg ggtcgtatag ctgttctaca aacttcaatt ctcaagttat
taatagccat 300tcagtaacca tccatgtgag ag 32216322DNAMus musculus
16gatgaagagt gtgaagtgca acttaatatt aagaggaatt ccaaacactc tgcctggaca
60ggagagttat ttaaaattga atgtcctgtg aaatactgtg ttcatagacc taatgtgact
120tggtgtaagc acaatggaac aatctgggta ccccttgaag ttggtcctca
gctatacact 180agttgggaag aaaatcgatc agttccggtt tttgttctcc
attttaaacc aatacatctc 240agtgataacg ggtcgtatag ctgttctaca
aacttcaatt ctcaagttat taatagccat 300tcagtaacca tccatgtgag ag
32217322DNAMus musculus 17gatgaagagt gtgaagtgca acttaatatt
aagaggaatt ccaaacactc tgcctggaca 60ggagagttat ttaaaattga atgtcctgtg
aaatactgtg ttcatagacc taatgtgact 120tggtgtaagc acaatggaac
aatctgggta ccccttgaag ttggtcctca gctatacact 180agttgggaag
aaaatcgatc agttccggtt tttgttctcc attttaaacc aatacatctc
240agtgataacg ggtcgtatag ctgttctaca aacttcaatt ctcaagttat
taatagccat 300tcagtaacca tccatgtgag ag 32218322DNAMus musculus
18gatgaagagt gtgaagtgca acttaatatt aagaggaatt ccaaacactc tgcctggaca
60ggagagttat ttaaaattga atgtcctgtg aaatactgtg ttcatagacc tcatgtgact
120tggtgtaagc acaatggaac aatctgggta ccccttgaag ttggtcctca
gctatacact 180agttgggaag aaaatcgatc agttccggtt tttgttctcc
attttaaacc aatacatctc 240agtgataacg ggtcgtatag ctgttctaca
aacttcaatt ctcaagttat taatagccat 300tcagtaacca tccatgtgag ag
32219322DNAMus musculus 19gatgaagagt gtgaagtgca acttaatatt
aagaggaatt ccaaacactc tgcctggaca 60ggagagttat ttaaaattga atgtcctgtg
aaatactgtg ttcatagacc tcatgtgact 120tggtgtaagc acaatggaac
aatctgggta ccccttgaag ttggtcctca gctatacact 180agttgggaag
aaaatcgatc agttccggtt tttgttctcc attttaaacc aatacatctc
240agtgataacg ggtcgtatag ctgttctaca aacttcaatt ctcaagttat
taatagccat 300tcagtaacca tccatgtgag ag 32220322DNAMus musculus
20gatgaagagt gtgaagtgca acttaatatt aagaggaatt ccaaacactc tgcctggaca
60ggagagttat ttaaaattga atgtcctgtg aaatactgtg ttcatagacc taatgtgact
120tggtgtaagc acaatggaac aatctgggta ccccttgaag ttggtcctca
gctatacact 180agttgggaag aaaatcgatc agttccggtt tttgttctcc
attttaaacc aatacatctc 240agtgataacg ggtcgtatag ctgttctaca
aacttcaatt ctcaagttat taatagccat 300tcagtaacca tccatgtgag ag
32221322DNAMus musculus 21gatgaagagt gtgaagtgca acttaatatt
aagaggaatt ccaaacactc tgcctggaca 60ggagagttat ttaaaattga atgtcctgtg
aaatactgtg ttcatagacc taatgtgact 120tggtgtaagc acaatggaac
aatctgggta ccccttgaag ttggtcctca gctatacact 180agttgggaag
aaaatcgatc agttccggtt tttgttctcc attttaaacc aatacatctc
240agtgataacg ggtcgtatag ctgttctaca aacttcaatt ctcaagttat
taatagccat 300tcagtaacca tccatgtgag ag 32222322DNAMus musculus
22gatgaagagt gtgaagtgca acttaatatt aagaggaatt ccaaacactc tgcctggaca
60ggagagttat ttaaaattga atgtcctgtg aaatactgtg ttcatagacc taatgtgact
120tggtgtaagc acaatggaac aatctgggta ccccttgaag ttggtcctca
gctatacact 180agttgggaag aaaatcgatc agttccggtt tttgttctcc
attttaaacc aatacatctc 240agtgataacg ggtcgtatag ctgttctaca
aacttcaatt ctcaagttat taatagccat 300tcagtaacca tccatgtgag ag
32223322DNAMus musculus 23gatgaagagt gtgaagtgca acttaatatt
aagaggaatt ccaaacactc tgcctggaca 60ggagagttat ttaaaattga atgtcctgtg
aaatactgtg ttcatagacc taatgtgact 120tggtgtaagc acaatggaac
aatctgggta ccccttgaag ttggtcctca gctatacact 180agttgggaag
aaaatcgatc agttccggtt tttgttctcc attttaaacc aatacatctc
240agtgataacg ggtcgtatag ctgttctaca aacttcaatt ctcaagttat
taatagccat 300tcagtaacca tccatgtgag ag 32224322DNAMus musculus
24gatgaagagt gtgaagtgca acttaatatt aagaggaatt ccaaacactc tgcctggaca
60ggagagttat ttaaaattga atgtcctgtg gaatactgtg ttcatagacc tcatgtgact
120tggtgtaagc acaatggaac aatctgggta ccccttgaag ttggtcctca
gctatacact 180agttgggaag aaaatcgatc agttccggtt tttgttctcc
attttaaacc aatacatctc 240agtgataacg ggtcgtatag ctgttctaca
aacttcaatt ctcaagttat taatagccat 300tcagtaacca tccatgtgag ag
32225322DNAMus musculus 25gatgaagagt gtccagtgca acttactatt
acgaggaatt ccaaacagtc tgccaggaca 60ggagagttat ttaaaattca atgtcctgtg
aaatactgtg ttcatagacc taatgtgact 120tggtgtaagc acaatggaac
aatctgtgta ccccttgagg ttagccctca gctatacact 180agttgggaag
aaaatcgatc agttccggtt tttgttctcc attttaaacc aatacatctc
240agtgataatg ggtcgtatag ctgttctaca aacttcaatt ctcaagttat
taatagccat 300tcagtaacca tccatgtgac ag 32226322DNAMus musculus
26gatgaagagt gtgaagtgca acttaatatt aagaggaatt ccaaacactc tgcctggaca
60ggagagttat ttaaaattga atgtcctgtg gaatactgtg ttcatagacc tcatgtgact
120tggtgtaagc acaatggaac aatctgggta ccccttgaag ttggtcctca
gctatacact 180agttgggaag aaaatcgatc agttccggtt tttgttctcc
attttaaacc aatacatctc 240agtgataacg ggtcgtatag ctgttctaca
aacttcaatt ctcaagttat taatagccat 300tcagtaacca tccatgtgag ag
32227322DNAMus musculus 27gatgaagagt gtgaagtgca acttaatatt
aagaggaatt ccaaacactc tgcctggaca 60ggagagttat ttaaaattga atgtcctgtg
aaatactgtg ttcatagacc taatgtgact 120tggtgtaagc acaatggaac
aatctgggta ccccttgaag ttggtcctca gctatacact 180agttgggaag
aaaatcgatc agttccggtt tttgttctcc attttaaacc aatacatctc
240agtgataacg ggtcgtatag ctgttctaca aacttcaatt ctcaagttat
taatagccat 300tcagtaacca tccatgtgag ag 3222826DNAHomo sapiens
28agctctgaag atctctaggg aggaag 262932DNAHomo sapiens 29catgctcgag
gaaggtccag acagaggtat tg 323029DNAHomo sapiens 30gttcagatcc
aaggatgctc cagaggccc 293132DNAHomo sapiens 31gagcatcctt ggatctgaac
aaaagctgat ta 323229DNAHomo sapiens 32ctttctcaca gagctcgtac
aggtcctct 293331DNAHomo sapiens 33gtacgagctc tgtgagaaag ctactaagag
g 313430DNAHomo sapiens 34tgatattcca taaacctgcc actgagccag
303533DNAHomo sapiens 35tggcaggttt atggaatatc aaccaggtta gtg
333631DNAHomo sapiens 36gcttttgttc acttctcaca caaatggatg c
313730DNAHomo sapiens 37tgaggagtga acaaaagctg attagcgaag
303827DNAHomo sapiens 38ccgctcgagc tcctacaggt cctcttc 273930DNAHomo
sapiens 39gaagatctgc aggaaatgaa gacattgcct 304035DNAHomo sapiens
40tcagcttttg ttccccatgg atgttccaga tgtcc 354134DNAHomo sapiens
41catccatggg gaacaaaagc tgattagcga agag 344235DNAHomo sapiens
42cacatgattc tttcaggtcc tcttcgctaa tcagc 354335DNAHomo sapiens
43gaggacctga aagaatcatg tgatgtacag cttta 354432DNAHomo sapiens
44ccgctcgagt tggagtcaga aacagactta ac 324530DNAHomo sapiens
45tgaggagtga acaaaagctg attagcgaag 304630DNAHomo sapiens
46tgaggagtga acaaaagctg attagcgaag 304735DNAHomo sapiens
47gaaactggaa tttatgataa tgaccctgac ctttg 354835DNAHomo sapiens
48gggtcattat caaaaattcc agtttctgat agcag 354935DNAHomo sapiens
49accaggcatt gtttatgctt ccctgaacca ttctg 355028DNAHomo sapiens
50agggaagcaa aaacaatgcc tggtttgt 285133DNAHomo sapiens 51gcaccaacag
aatatgcatc catatgtgtg agg 335233DNAHomo sapiens 52atatggatgc
aaattctgtt ggtgcttctt tta 335320DNAHomo sapiens 53tttggcctaa
gatgctgcta 205420DNAHomo sapiens 54cacagattgg gtacgacatg
205524DNAHomo sapiens 55ttttccatca ctgatatgtg cagg 245622DNAHomo
sapiens 56ggtccctgtt ggagtcagaa ac 2257306PRTMus musculus 57Met Ala
Cys Asn Cys Gln Leu Met Gln Asp Thr Pro Leu Leu Lys Phe1 5 10 15Pro
Cys Pro Arg Leu Ile Leu Leu Phe Val Leu Leu Ile Arg Leu Ser 20 25
30Gln Val Ser Ser Asp Val Asp Glu Gln Leu Ser Lys Ser Val Lys Asp
35 40 45Lys Val Leu Leu Pro Cys Arg Tyr Asn Ser Pro His Glu Asp Glu
Ser 50 55 60Glu Asp Arg Ile Tyr Trp Gln Lys His Asp Lys Val Val Leu
Ser Val65 70 75 80Ile Ala Gly Lys Leu Lys Val Trp Pro Glu Tyr Lys
Asn Arg Thr Leu 85 90 95Tyr Asp Asn Thr Thr Tyr Ser Leu Ile Ile Leu
Gly Leu Val Leu Ser 100 105 110Asp Arg Gly Thr Tyr Ser Cys Val Val
Gln Lys Lys Glu Arg Gly Thr 115 120 125Tyr Glu Val Lys His Leu Ala
Leu Val Lys Leu Ser Ile Lys Ala Asp 130 135 140Phe Ser Thr Pro Asn
Ile Thr Glu Ser Gly Asn Pro Ser Ala Asp Thr145 150 155 160Lys Arg
Ile Thr Cys Phe Ala Ser Gly Gly Phe Pro Lys Pro Arg Phe 165 170
175Ser Trp Leu Glu Asn Gly Arg Glu Leu Pro Gly Ile Asn Thr Thr Ile
180 185 190Ser Gln Asp Pro Glu Ser Glu Leu Tyr Thr Ile Ser Ser Gln
Leu Asp 195 200 205Phe Asn Thr Thr Arg Asn His Thr Ile Lys Cys Leu
Ile Lys Tyr Gly 210 215 220Asp Ala His Val Ser Glu Asp Phe Thr Trp
Glu Lys Pro Pro Glu Asp225 230 235 240Pro Pro Asp Ser Lys Asn Thr
Leu Val Leu Phe Gly Ala Gly Phe Gly 245 250 255Ala Val Ile Thr Val
Val Val Ile Val Val Ile Ile Lys Cys Phe Cys 260 265 270Lys His Arg
Ser Cys Phe Arg Arg Asn Glu Ala Ser Arg Glu Thr Asn 275 280 285Asn
Ser Leu Thr Phe Gly Pro Glu Glu Ala Leu Ala Glu Gln Thr Val 290 295
300Phe Leu30558309PRTMus musculus 58Met Asp Pro Arg Cys Thr Met Gly
Leu Ala Ile Leu Ile Phe Val Thr1 5 10 15Val Leu Leu Ile Ser Asp Ala
Val Ser Val Glu Thr Gln Ala Tyr Phe 20 25 30Asn Gly Thr Ala Tyr Leu
Pro Cys Pro Phe Thr Lys Ala Gln Asn Ile 35 40 45Ser Leu Ser Glu Leu
Val Val Phe Trp Gln Asp Gln Gln Lys Leu Val 50 55 60Leu Tyr Glu His
Tyr Leu Gly Thr Glu Lys Leu Asp Ser Val Asn Ala65 70 75 80Lys Tyr
Leu Gly Arg Thr Ser Phe Asp Arg Asn Asn Trp Thr Leu Arg 85 90 95Leu
His Asn Val Gln Ile Lys Asp Met Gly Ser Tyr Asp Cys Phe Ile 100 105
110Gln Lys Lys Pro Pro Thr Gly Ser Ile Ile Leu Gln Gln Thr Leu Thr
115 120 125Glu Leu Ser Val Ile Ala Asn Phe Ser Glu Pro Glu Ile Lys
Leu Asp 130 135 140Gln Asn Val Thr Gly Asn Ser Gly Ile Asn Leu Thr
Cys Met Ser Lys145 150 155 160Gln Gly His Pro Lys Pro Lys Lys Met
Tyr Phe Leu Ile Thr Asn Ser 165 170 175Thr Asn Glu Tyr Gly Asp Asn
Met Gln Ile Ser Gln Asp Asn Val Thr 180 185 190Glu Leu Phe Ser Ile
Ser Asn Ser Leu Ser Leu Ser Phe Pro Asp Gly 195 200 205Val Trp His
Met Thr Val Val Cys Val Leu Glu Thr Glu Ser Met Lys 210 215 220Ile
Ser Ser Lys Pro Leu Asn Phe Thr Gln Glu Phe Pro Ser Ala Gln225 230
235 240Thr Tyr Trp Lys Glu Ile Thr Ala Ser Val Thr Val Ala Leu Leu
Leu 245 250 255Val Met Leu Leu Ile Ile Val Cys His Lys Lys Pro Asn
Gln Pro Ser 260 265 270Arg Pro Ser Asn Thr Ala Ser Lys Leu Glu Arg
Asp Ser Asn Ala Asp 275 280 285Arg Glu Thr Ile Asn Leu Lys Glu Leu
Glu Pro Gln Ile Ala Ser Ala 290 295 300Lys Pro Asn Ala
Glu30559323PRTMus musculus 59Met Gln Leu Lys Cys Pro Cys Phe Val
Ser Leu Gly Thr Arg Gln Pro1 5 10 15Val Trp Lys Lys Leu His Val Ser
Ser Gly Phe Phe Ser Gly Leu Gly 20 25 30Leu Phe Leu Leu Leu Leu Ser
Ser Leu Cys Ala Ala Ser Ala Glu Thr 35 40 45Glu Val Gly Ala Met Val
Gly Ser Asn Val Val Leu Ser Cys Ile Asp 50 55 60Pro His Arg Arg His
Phe Asn Leu Ser Gly Leu Tyr Val Tyr Trp Gln65 70 75 80Ile Glu Asn
Pro Glu Val Ser Val Thr Tyr Tyr Leu Pro Tyr Lys Ser 85 90 95Pro Gly
Ile Asn Val Asp Ser Ser Tyr Lys Asn Arg Gly His Leu Ser 100 105
110Leu Asp Ser Met Lys Gln Gly Asn Phe Ser Leu Tyr Leu Lys Asn Val
115 120 125Thr Pro Gln Asp Thr Gln Glu Phe Thr Cys Arg Val Phe Met
Asn Thr 130 135 140Ala Thr Glu Leu Val Lys Ile Leu Glu Glu Val Val
Arg Leu Arg Val145 150 155 160Ala Ala Asn Phe Ser Thr Pro Val Ile
Ser Thr Ser Asp Ser Ser Asn 165 170 175Pro Gly Gln Glu Arg Thr Tyr
Thr Cys Met Ser Lys Asn Gly Tyr Pro 180 185 190Glu Pro Asn Leu Tyr
Trp Ile Asn Thr Thr Asp Asn Ser Leu Ile Asp 195 200 205Thr Ala Leu
Gln Asn Asn Thr Val Tyr Leu Asn Lys Leu Gly Leu Tyr 210 215 220Asp
Val Ile Ser Thr Leu Arg Leu Pro Trp Thr Ser Arg Gly Asp Val225 230
235 240Leu Cys Cys Val Glu Asn Val Ala Leu His Gln Asn Ile Thr Ser
Ile 245 250 255Ser Gln Ala Glu Ser Phe Thr Gly Asn Asn Thr Lys Asn
Pro Gln Glu 260 265 270Thr His Asn Asn Glu Leu Lys Val Leu Val Pro
Val Leu Ala Val Leu 275 280 285Ala Ala Ala Ala Phe Val Ser Phe Ile
Ile Tyr Arg Arg Thr Arg Pro 290 295 300His Arg Ser Tyr Thr Gly Pro
Lys Thr Val Gln Leu Glu Leu Thr Asp305 310 315 320His Ala
Asn60290PRTMus musculus 60Met Arg Ile Phe Ala Gly Ile Ile Phe Thr
Ala Cys Cys His Leu Leu1 5 10 15Arg Ala Phe Thr Ile Thr Ala Pro Lys
Asp Leu Tyr Val Val Glu Tyr 20 25 30Gly Ser Asn Val Thr Met Glu Cys
Arg Phe Pro Val Glu Arg Glu Leu 35 40 45Asp Leu Leu Ala Leu Val Val
Tyr Trp Glu Lys Glu Asp Glu Gln Val 50 55 60Ile Gln Phe Val Ala Gly
Glu Glu Asp Leu Lys Pro Gln His Ser Asn65 70 75 80Phe Arg Gly Arg
Ala Ser Leu Pro Lys Asp Gln Leu Leu Lys Gly Asn 85 90 95Ala Ala Leu
Gln Ile Thr Asp Val Lys Leu Gln Asp Ala Gly Val Tyr 100 105 110Cys
Cys Ile Ile Ser Tyr Gly Gly Ala Asp Tyr Lys Arg Ile Thr Leu 115 120
125Lys Val Asn Ala Pro Tyr Arg Lys Ile Asn Gln Arg Ile Ser Val Asp
130 135 140Pro Ala Thr Ser Glu His Glu Leu Ile Cys Gln Ala Glu Gly
Tyr Pro145 150 155 160Glu Ala Glu Val Ile Trp Thr Asn Ser Asp His
Gln Pro Val Ser Gly 165 170 175Lys Arg Ser Val Thr Thr Ser Arg Thr
Glu Gly Met Leu Leu Asn Val 180 185 190Thr Ser Ser Leu Arg Val Asn
Ala Thr Ala Asn Asp Val Phe
Tyr Cys 195 200 205Thr Phe Trp Arg Ser Gln Pro Gly Gln Asn His Thr
Ala Glu Leu Ile 210 215 220Ile Pro Glu Leu Pro Ala Thr His Pro Pro
Gln Asn Arg Thr His Trp225 230 235 240Val Leu Leu Gly Ser Ile Leu
Leu Phe Leu Ile Val Val Ser Thr Val 245 250 255Leu Leu Phe Leu Arg
Lys Gln Val Arg Met Leu Asp Val Glu Lys Cys 260 265 270Gly Val Glu
Asp Thr Ser Ser Lys Asn Arg Asn Asp Thr Gln Phe Glu 275 280 285Glu
Thr 29061247PRTMus musculus 61Met Leu Leu Leu Leu Pro Ile Leu Asn
Leu Ser Leu Gln Leu His Pro1 5 10 15Val Ala Ala Leu Phe Thr Val Thr
Ala Pro Lys Glu Val Tyr Thr Val 20 25 30Asp Val Gly Ser Ser Val Ser
Leu Glu Cys Asp Phe Asp Arg Arg Glu 35 40 45Cys Thr Glu Leu Glu Gly
Ile Arg Ala Ser Leu Gln Lys Val Glu Asn 50 55 60Asp Thr Ser Leu Gln
Ser Glu Arg Ala Thr Leu Leu Glu Glu Gln Leu65 70 75 80Pro Leu Gly
Lys Ala Leu Phe His Ile Pro Ser Val Gln Val Arg Asp 85 90 95Ser Gly
Gln Tyr Arg Cys Leu Val Ile Cys Gly Ala Ala Trp Asp Tyr 100 105
110Lys Tyr Leu Thr Val Lys Val Lys Ala Ser Tyr Met Arg Ile Asp Thr
115 120 125Arg Ile Leu Glu Val Pro Gly Thr Gly Glu Val Gln Leu Thr
Cys Gln 130 135 140Ala Arg Gly Tyr Pro Leu Ala Glu Val Ser Trp Gln
Asn Val Ser Val145 150 155 160Pro Ala Asn Thr Ser His Ile Arg Thr
Pro Glu Gly Leu Tyr Gln Val 165 170 175Thr Ser Val Leu Arg Leu Lys
Pro Gln Pro Ser Arg Asn Phe Ser Cys 180 185 190Met Phe Trp Asn Ala
His Met Lys Glu Leu Thr Ser Ala Ile Ile Asp 195 200 205Pro Leu Ser
Arg Met Glu Pro Lys Val Pro Arg Thr Trp Pro Leu His 210 215 220Val
Phe Ile Pro Ala Cys Thr Ile Ala Leu Ile Phe Leu Ala Ile Val225 230
235 240Ile Ile Gln Arg Lys Arg Ile 24562316PRTMus musculus 62Met
Leu Arg Gly Trp Gly Gly Pro Ser Val Gly Val Cys Val Arg Thr1 5 10
15Ala Leu Gly Val Leu Cys Leu Cys Leu Thr Gly Ala Val Glu Val Gln
20 25 30Val Ser Glu Asp Pro Val Val Ala Leu Val Asp Thr Asp Ala Thr
Leu 35 40 45Arg Cys Ser Phe Ser Pro Glu Pro Gly Phe Ser Leu Ala Gln
Leu Asn 50 55 60Leu Ile Trp Gln Leu Thr Asp Thr Lys Gln Leu Val His
Ser Phe Thr65 70 75 80Glu Gly Arg Asp Gln Gly Ser Ala Tyr Ser Asn
Arg Thr Ala Leu Phe 85 90 95Pro Asp Leu Leu Val Gln Gly Asn Ala Ser
Leu Arg Leu Gln Arg Val 100 105 110Arg Val Thr Asp Glu Gly Ser Tyr
Thr Cys Phe Val Ser Ile Gln Asp 115 120 125Phe Asp Ser Ala Ala Val
Ser Leu Gln Val Ala Ala Pro Tyr Ser Lys 130 135 140Pro Ser Met Thr
Leu Glu Pro Asn Lys Asp Leu Arg Pro Gly Asn Met145 150 155 160Val
Thr Ile Thr Cys Ser Ser Tyr Gln Gly Tyr Pro Glu Ala Glu Val 165 170
175Phe Trp Lys Asp Gly Gln Gly Val Pro Leu Thr Gly Asn Val Thr Thr
180 185 190Ser Gln Met Ala Asn Glu Arg Gly Leu Phe Asp Val His Ser
Val Leu 195 200 205Arg Val Val Leu Gly Ala Asn Gly Thr Tyr Ser Cys
Leu Val Arg Asn 210 215 220Pro Val Leu Gln Gln Asp Ala His Gly Ser
Val Thr Ile Thr Gly Gln225 230 235 240Pro Leu Thr Phe Pro Pro Glu
Ala Leu Trp Val Thr Val Gly Leu Ser 245 250 255Val Cys Leu Val Val
Leu Leu Val Ala Leu Ala Phe Val Cys Trp Arg 260 265 270Lys Ile Lys
Gln Ser Cys Glu Glu Glu Asn Ala Gly Ala Glu Asp Gln 275 280 285Asp
Gly Asp Gly Glu Gly Ser Lys Thr Ala Leu Arg Pro Leu Lys Pro 290 295
300Ser Glu Asn Lys Glu Asp Asp Gly Gln Glu Ile Ala305 310 315
* * * * *