U.S. patent application number 15/654315 was filed with the patent office on 2017-11-16 for crosslinking of cd22 by epratuzumab triggers bcr signaling and caspase-dependent apoptosis in hematopoietic cancer cells.
The applicant listed for this patent is Immunomedics, Inc.. Invention is credited to Chien-Hsing Chang, David M. Goldenberg.
Application Number | 20170326238 15/654315 |
Document ID | / |
Family ID | 55016250 |
Filed Date | 2017-11-16 |
United States Patent
Application |
20170326238 |
Kind Code |
A1 |
Chang; Chien-Hsing ; et
al. |
November 16, 2017 |
CROSSLINKING OF CD22 BY EPRATUZUMAB TRIGGERS BCR SIGNALING AND
CASPASE-DEPENDENT APOPTOSIS IN HEMATOPOIETIC CANCER CELLS
Abstract
Extensive crosslinking of CD22 by plate-immobilized epratuzumab
induced intracellular changes in Daudi cells similar to ligating
B-cell antigen receptor (BCR) with a sufficiently high amount of
anti-IgM. Either treatment leads to phosphorylation of CD22, CD79a
and CD79b, along with their translocation to lipid rafts, both of
which were needed to induce caspase-dependent apoptosis.
Immobilization also induced stabilization of F-actin,
phosphorylation of Lyn, ERKs and JNKs, generation of reactive
oxygen species (ROS), decrease in mitochondria membrane potential
(.DELTA..psi..sub.m), upregulation of pro-apoptotic Bax, and
downregulation of anti-apoptotic Bcl-xl and Mcl-1. Several of the
in vitro effects of immobilized epratuzumab, including apoptosis,
drop in .DELTA..psi..sub.m, and generation of ROS, were observed
with soluble epratuzumab in Daudi cells co-cultivated with human
umbilical vein endothelial cells. The in vivo mechanism of
non-ligand-blocking epratuzumab may, in part, involve the unmasking
of CD22 to facilitate the trans-interaction of B cells with
vascular endothelium.
Inventors: |
Chang; Chien-Hsing;
(Downingtown, PA) ; Goldenberg; David M.;
(Mendham, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Immunomedics, Inc. |
Morris Plains |
NJ |
US |
|
|
Family ID: |
55016250 |
Appl. No.: |
15/654315 |
Filed: |
July 19, 2017 |
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14861636 |
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9757458 |
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15654315 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61K 2039/505 20130101;
A61K 45/06 20130101; C07K 2317/73 20130101; C07K 16/3007 20130101;
C07K 2317/94 20130101; C07K 2317/31 20130101; C07K 2317/55
20130101; C07K 2317/24 20130101; C07K 16/2833 20130101; C07K 14/56
20130101; C07K 2317/54 20130101; C07K 2317/92 20130101; C07K
2317/734 20130101; C07K 2319/00 20130101; C07K 16/468 20130101;
C07K 16/2887 20130101; C07K 16/2803 20130101; C07K 2317/732
20130101; C07K 2317/77 20130101 |
International
Class: |
A61K 45/06 20060101
A61K045/06; C07K 16/28 20060101 C07K016/28; C07K 16/28 20060101
C07K016/28; C07K 16/30 20060101 C07K016/30; C07K 16/46 20060101
C07K016/46; C07K 14/56 20060101 C07K014/56; C07K 16/28 20060101
C07K016/28 |
Claims
1. A method of inducing caspase-dependent apoptosis of CD22.sup.+
hematopoietic cancer cells comprising: a) exposing CD22.sup.+
hematopoietic cancer cells to an anti-CD22 antibody, wherein the
antibody is immobilized by attachment to a solid surface, and
wherein the antibody binds to the same epitope as epratuzumab; b)
inhibiting cis-interaction between CD22 and CD22 ligands on the
CD22.sup.+ hematopoietic cancer cells; c) promoting
trans-interaction between CD22 and CD22 ligands on other cells; and
d) inducing caspase-dependent apoptosis of CD22.sup.+ hematopoietic
cancer cells.
2. The method of claim 1, further comprising exposing the
CD22.sup.+ cells to at least one therapeutic agent that activates
caspase-dependent apoptosis.
3. The method of claim 2, wherein the therapeutic agent is selected
from the group consisting of troglitazone, etoposide, paclitaxel,
TRAIL, furanonaphthoquinones, and bortezomib.
4. The method of claim 1, wherein the anti-CD22 antibody is a
non-blocking antibody.
5. The method of claim 1, wherein exposing CD22.sup.+ hematopoietic
cancer cells to an anti-CD22 antibody unmasks CD22 on the surface
of the CD22.sup.+ cells.
6. The method of claim 1, wherein the anti-CD22 antibody is
epratuzumab.
7. The method of claim 1, wherein the anti-CD22 antibody is a
humanized antibody comprising the light chain CDR sequences CDR1
(KSSQSVLYSANHKYLA, SEQ ID NO:1), CDR2 (WASTRES, SEQ ID NO:2), and
CDR3 (HQYLSSWTF, SEQ ID NO:3) and the heavy chain CDR sequences
CDR1 (SYWLH, SEQ ID NO:4), CDR2 (YINPRNDYTEYNQNFKD, SEQ ID NO:5),
and CDR3 (RDITTFY, SEQ ID NO:6).
8. The method of claim 1, wherein the CD22.sup.+ cells are human
lymphoma cells or hematopoietic cancer B cells.
9. The method of claim 1, wherein the other cells are selected from
the group consisting of lymphocytes, monocytes, platelets, and
endothelial cells.
10. The method of claim 8, further comprising inducing
phosphorylation of CD22, CD79a and CD79b and translocation of CD22,
CD79a and CD79b to lipid rafts on the hematopoietic cancer B
cells.
11. The method of claim 1, further comprising inducing
stabilization of F-actin in the CD22.sup.+ hematopoietic cancer
cells.
12. The method of claim 1, further comprising inducing
phosphorylation of Lyn, ERKs and JNKs, generation of reactive
oxygen species (ROS), decrease in mitochondria membrane potential
(.DELTA..psi..sub.m), upregulation of pro-apoptotic Bax, and
downregulation of anti-apoptotic Bcl-xl and Mcl-1 in the CD22.sup.+
hematopoietic cancer cells.
13. The method of claim 5, wherein unmasking of CD22 promotes
trans-interaction of CD22.sup.+ hematopoietic cancer cells with
vascular endothelial cells.
14. The method of claim 8, further comprising inducing trogocytosis
of CD19, CD21, CD20, CD22 and CD79b from the cell membrane of the
hematopoietic cancer B cells.
15. A method of treating a hematopoietic cancer comprising: a)
administering an anti-CD22 antibody to a subject with CD22.sup.+
hematopoietic cancer, wherein the antibody is immobilized by
attachment to a solid surface, and wherein the antibody binds to
the same epitope as epratuzumab; b) unmasking CD22 on circulating
CD22.sup.+ hematopoietic cancer cells in the subject; and c)
inducing caspase-dependent apoptosis of CD22.sup.+ hematopoietic
cancer; wherein inducing apoptosis of CD22.sup.+ hematopoietic
cancer is effective to treat the cancer or immune disease.
16. The method of claim 15, further comprising administering at
least one therapeutic agent that activates caspase-dependent
apoptosis.
17. The method of claim 16, wherein the therapeutic agent is
selected from the group consisting of troglitazone, etoposide,
paclitaxel, TRAIL, furanonaphthoquinones, and bortezomib.
18. The method of claim 15, wherein the CD22.sup.+ cells are
hematopoietic cancer B cells.
19. The method of claim 15, further comprising inhibiting
cis-interaction between CD22 and CD22 ligands on the circulating
CD22.sup.+ hematopoietic cancer cells.
20. The method of claim 15, further comprising promoting
trans-interaction between CD22 on CD22.sup.+ hematopoietic cancer
cells and CD22 ligands on other cells.
21. The method of claim 15, wherein the anti-CD22 antibody is a
non-blocking antibody.
22. The method of claim 15, wherein the anti-CD22 antibody is
epratuzumab.
23. The method of claim 15, wherein the anti-CD22 antibody is a
humanized antibody comprising the light chain CDR sequences CDR1
(KSSQSVLYSANHKYLA, SEQ ID NO:1), CDR2 (WASTRES, SEQ ID NO:2), and
CDR3 (HQYLSSWTF, SEQ ID NO:3) and the heavy chain CDR sequences
CDR1 (SYWLH, SEQ ID NO:4), CDR2 (YINPRNDYTEYNQNFKD, SEQ ID NO:5),
and CDR3 (RDITTFY, SEQ ID NO:6).
24. The method of claim 18, further comprising inducing
phosphorylation of CD22, CD79a and CD79b and translocation of CD22,
CD79a and CD79b to lipid rafts on the hematopoietic cancer B
cells.
25. The method of claim 15, further comprising inducing
stabilization of F-actin in the CD22.sup.+ hematopoietic cancer
cells.
26. The method of claim 15, further comprising inducing
phosphorylation of Lyn, ERKs and JNKs, generation of reactive
oxygen species (ROS), decrease in mitochondria membrane potential
(.DELTA..psi..sub.m), upregulation of pro-apoptotic Bax, and
downregulation of anti-apoptotic Bcl-xl and Mcl-1 in the CD22.sup.+
hematopoietic cancer cells.
27. The method of claim 15, wherein unmasking of CD22 promotes
trans-interaction of CD22.sup.+ hematopoietic cancer cells with
vascular endothelial cells.
28. The method of claim 18, further comprising inducing
trogocytosis of CD19, CD21, CD20, CD22 and CD79b from the cell
membrane of the hematopoietic cancer B cells.
29. The method of claim 18, wherein the CD22.sup.+ hematopoietic
cancer is selected from the group consisting of indolent forms of
B-cell lymphoma, aggressive forms of B-cell lymphoma, chronic
lymphocytic leukemia, acute lymphocytic leukemia, hairy cell
leukemia, non-Hodgkin's lymphoma, Hodgkin's lymphoma, Burkitt
lymphoma, follicular lymphoma, diffuse B-cell lymphoma and mantle
cell lymphoma.
30. The method of claim 18, wherein the CD22.sup.+ hematopoietic
cancer is non-Hodgkin's lymphoma or acute lymphoblastic
leukemia.
31. The method of claim 15, further comprising administering a drug
selected from the group consisting of 5-fluorouracil, aplidin,
azaribine, anastrozole, anthracyclines, bendamustine, bleomycin,
bortezomib, bryostatin-1, busulfan, calicheamycin, camptothecin,
carboplatin, 10-hydroxycamptothecin, carmustine, celebrex,
chlorambucil, cisplatin (CDDP), Cox-2 inhibitors, irinotecan
(CPT-11), SN-38, carboplatin, cladribine, camptothecans,
cyclophosphamide, cytarabine, dacarbazine, docetaxel, dactinomycin,
daunorubicin, doxorubicin, 2-pyrrolinodoxorubicine (2P-DOX), a
prodrug form of 2-pyrrolinodoxorubicine (P2PDox), cyano-morpholino
doxorubicin, doxorubicin glucuronide, epirubicin glucuronide,
estramustine, epipodophyllotoxin, estrogen receptor binding agents,
etoposide (VP16), etoposide glucuronide, etoposide phosphate,
floxuridine (FUdR), 3',5'-O-dioleoyl-FudR (FUdR-dO), fludarabine,
flutamide, farnesyl-protein transferase inhibitors, gemcitabine,
hydroxyurea, idarubicin, ifosfamide, L-asparaginase, lenolidamide,
leucovorin, lomustine, mechlorethamine, melphalan, mercaptopurine,
6-mercaptopurine, methotrexate, mitoxantrone, mithramycin,
mitomycin, mitotane, navelbine, nitrosourea, plicomycin,
procarbazine, paclitaxel, pentostatin, PSI-341, raloxifene,
semustine, streptozocin, tamoxifen, taxol, temazolomide (an aqueous
form of DTIC), transplatinum, thalidomide, thioguanine, thiotepa,
teniposide, topotecan, uracil mustard, vinorelbine, vinblastine,
vincristine and vinca alkaloids.
32. The method of claim 15, further comprising administering an
immunomodulator selected from the group consisting of a cytokine, a
stem cell growth factor, a lymphotoxin, a hematopoietic factor, a
colony stimulating factor (CSF), an interferon (IFN),
erythropoietin, and thrombopoietin.
33. The method of claim 32, wherein the cytokine is selected from
the group consisting of human growth hormone, N-methionyl human
growth hormone, bovine growth hormone, parathyroid hormone,
thyroxine, insulin, proinsulin, relaxin, prorelaxin, follicle
stimulating hormone (FSH), thyroid stimulating hormone (TSH),
luteinizing hormone (LH), hepatic growth factor, prostaglandin,
fibroblast growth factor, prolactin, placental lactogen, OB
protein, tumor necrosis factor-.alpha., tumor necrosis
factor-.beta., mullerian-inhibiting substance, mouse
gonadotropin-associated peptide, inhibin, activin, vascular
endothelial growth factor, integrin, thrombopoietin (TPO),
NGF-.beta., platelet-growth factor, TGF-.alpha., TGF-.beta.,
insulin-like growth factor-I, insulin-like growth factor-II,
erythropoietin (EPO), osteoinductive factors, interferon-.alpha.,
interferon-.beta., interferon-.gamma., macrophage-CSF (M-CSF),
IL-1, IL-1.alpha., IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9,
IL-10, IL-11, IL-12, IL-13, IL-14, IL-15, IL-16, IL-17, IL-18,
IL-21, IL-25, LIF, FLT-3, angiostatin, thrombospondin, endostatin,
tumor necrosis factor and lymphotoxin.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 14/861,636, filed Sep. 22, 2015, which was a
continuation-in-part of U.S. patent application Ser. No. 14/243,512
(now abandoned), filed Apr. 2, 2014, which was a
continuation-in-part of U.S. patent application Ser. No. 13/693,476
(now issued U.S. Pat. No. 9,192,664), filed Dec. 4, 2012, which
claimed the benefit under 35 U.S.C. 119(e) of Provisional U.S.
Patent Application Ser. Nos. 61/566,828, filed Dec. 5, 2011;
61/609,075, filed Mar. 9, 2012; 61/682,508, filed Aug. 13, 2012;
and 61/718,226, filed Oct. 25, 2012. U.S. patent application Ser.
No. 14/243,512 claimed the benefit under 35 U.S.C. 119(e) of
Provisional U.S. Patent Application Ser. Nos. 61/808,005, filed
Apr. 3, 2013, 61/832,558, filed Jun. 7, 2013 and 61/941,100, filed
Feb. 18, 2014. This application claims the benefit under 35 U.S.C.
119(e) of Provisional U.S. Patent Application Ser. No. 62/054,581,
filed Sep. 24, 2014. The text of each claimed priority application
is incorporated herein by reference in its entirety.
SEQUENCE LISTING
[0002] The instant application contains a Sequence Listing which
has been submitted in ASCII format via EFS-Web and is hereby
incorporated by reference in its entirety. Said ASCII copy, created
on Sep. 22, 2015, is named IMM349US1_SL.txt and is 13,893 bytes in
size.
FIELD OF THE INVENTION
[0003] This invention relates to compositions and methods of use of
antibodies against human CD22. Preferably, the antibodies provide
extensive cross-linking of CD22 in vitro or in vivo. More
preferably, antibody based cross-linking is of use to treat
hematopoietic cancer by mechanisms involving BCR signaling and/or
caspase-dependent apoptosis. Other changes induced by cross-linking
CD22 may include phosphorylation of CD22, CD79a and CD79b, along
with their translocation to lipid rafts, both of which were
essential for effecting caspase-dependent apoptosis. Still other
changes induced by CD22 cross-linking by anti-CD22 antibodies may
include stabilization of F-actin, phosphorylation of Lyn, ERKs and
JNKs, generation of reactive oxygen species (ROS), decrease in
mitochondria membrane potential (.DELTA..psi..sub.m), upregulation
of pro-apoptotic Bax, and downregulation of anti-apoptotic Bcl-xl
and Mcl-1. These changes suggest that the in vivo mechanism of
action of anti-CD22 antibody therapy may involve the unmasking of
CD22 to facilitate the trans-interaction of B cells with vascular
endothelium.
BACKGROUND
[0004] CD22 is a 135-kD type I transmembrane sialoglycoprotein of
the immunoglobulin (Ig) superfamily. CD22 expression is specific to
B cells can be detected in the cytoplasm of pro-B and pre-B cells,
as well as on the surface of IgM.sup.+ B cells upon the appearance
of IgD, but not on terminally-differentiated plasma cells (Tedder
et al., 1997, Ann Rev Immunol 15:481-504). CD22 is strongly
expressed on follicular, mantle and marginal-zone B cells, but is
weakly present in germinal B cells (Dorner & Goldenberg, 2007,
Ther Clin Risk Manag 3:954-59). CD22 is an inhibitory co-receptor
that downmodulates B-cell receptor (BCR) signaling by setting a
signaling threshold that prevents overstimulation of B cells
(Nitschke, 2005, Curr Opin Immunol 17:290-97).
[0005] Structurally, CD22 in its extracellular region comprises 7
immunoglobulin-like domains, of which the two N-terminal domains
are involved in ligand binding (Law et al., 1995, J Immunol
155:3368-76). The cytoplasmic tail of CD22 contains 6 conserved
tyrosine (Y) residues, four of which (Y.sup.762, Y.sup.796,
Y.sup.822, and Y.sup.842) in hCD22 are considered to be localized
within the immunoreceptor tyrosine-based inhibition motifs (ITIM)
(Wilson et al., 1991, J Exp Med 173:137-46; Ravetch & Lanier,
2000, Science 290:84-9; Sato et al., 1998, Semin Immunol
10:287-97). These tyrosine residues also fit in the specific
internalization motifs of YXXO (where O denotes a hydrophobic
residue) (Bonifacino et al., 2003, Ann Rev Biochem 72:395-447),
which mediate the recruitment of CD22 to clathrin-coated pits and
are required for the internalization of CD22 (John et al., 2003, J
Immunol 170''3534-43). Whereas endocytosed CD22 has been documented
to be degraded intracellularly (Shan & Press, 1995, J Immunol
154:4466-75), a recent report contended that CD22 instead is
constitutively recycled back to the cell surface (O'Reilly et al.,
2011, J Immunol 186:1554-63). Functionally, CD22 recognizes
.alpha.2,6-linked sialic acids on glycoconjugates in both cis (on
the same cell) and trans (on different cells) interactions, and
modulates B cells via interaction with CD79a and CD79b, the
signaling components of the BCR complex (Razi & Varki, 1998
95:7469-74; Engels et al., 1993, J Immunol 150:4719-32; Leprince et
al., 1993, Proc Natl Acad Sci USA 90:3236-40). Crosslinking the BCR
with cognate antigens or appropriate antibodies against membrane
immunoglobulin (mIg) on the cell surface induces translocation of
the aggregated BCR complex to lipid rafts (Petri et al., 2000, J
Immunol 165:1220-27), where CD79a, CD79b and CD22, among others,
are phosphorylated by Lyn (Smith et al., 1998, J Exp Med
187:807-11), which in turn triggers various downstream signaling
pathways, culminating in proliferation, survival, or death (Niiro
et al., 2002, Nat Rev Immunol 2:945-56).
[0006] Antibodies against CD22, such as epratuzumab (hLL2), have
been used for treatment of a variety of cancers and autoimmune
diseases, including but not limited to acute lymphoblastic leukemia
(Hoelzer et al., 2013, Curr Opin Oncol 25:701-6), chronic
lymphocytic leukemia (Macromatis & Cheson, 2004, Blood Rev
18:137-48), non-Hodgkin's lymphoma (Leonard et al., 2004, Clin
Cancer Res 10:5327-34; Dorner & Goldenberg, 2007), follicular
lymphoma (Illidge & Morchhauser, 2011, Best Pract Res Clin
Haematol 24:279-93), diffuse large B-cell lymphoma (Micallef et
al., 2011, Blood 118:4053-61), mantle cell lymphoma (Sharkey et
al., 2012, Mol Cancer Ther 11:224-34), systemic lupus erythematosus
(Dorner & Goldenberg, 2007; Strand et al., 2014, Rheumatology
53:502-11; Wallace & Goldenberg, 2013, Lupus 22:400-5; Wallace
et al., 2013, Rheumatology 52:1313-22; Wallace et al., 2014, Ann
Rheum Dis 73:183-90), and primary Sjogren's syndrome (Steinfeld et
al., 2006, Arthritis Res Ther 8:R129; Dorner & Goldenberg,
2007). Because CD22 regulates B-cell functions and survival, it is
an important link for modulating humoral immunity and proliferation
of B-cell lymphomas and a target for therapeutic antibodies in
cancer and autoimmune disease (Dorner & Goldenberg, 2007).
[0007] Epratuzumab (hLL2), a humanized monoclonal antibody specific
for human CD22 (Leung et al., 1995, Mol Immunol 32:1413-27), is
currently under clinical investigation for the treatment of
non-Hodgkin lymphoma (NHL) (Leonard et al., 2004, Clin Cancer Res
10:5327-34; Leonard et al., 2009, Cancer 113:2714-23), pediatric
and adult acute lymphoblastic leukemia (Raetz et al., 2008, J Clin
Oncol 26:3756-62; Advani et al., 2014, Br J Haematol 165:504-9),
systemic lupus erythematosus (SLE) (Wallace et al., 2013, Lupus
22:400-5; Wallace et al., 2013, Rheumatology 52:1313-22; Strand et
al., Rheumatology 53:502-11), and has shown promise in patients
with primary Sjogren's syndrome in a phase I/II study (Steinfeld et
al., 2006, Arthritis Res Ther 8:R129). Research on anti-CD22
antibodies, which can be either blocking or nonblocking (Tuscano et
al., 1996, Blood 87:4723-30), has also led to intriguing
observations that CD22 may positively or negatively affect
BCR-mediated signaling pathways, with the ultimate outcome
depending on the characteristics of the B cells (differentiation
stage, expression of BCR isotype, and being malignant, abnormal, or
normal) (Tuscano et al., 1996, Blood 87:4723-30; Pezzutto et al,
1987, J Immunol 138:98-103; Pezzutto et al., 1988, J Immunol
140:1791-95; Nitschke et al., 2005, Curr Opin Immunol 17:290-97).
Thus, fully understanding the role of CD22 in B-cell malignancies,
as well as B-cell-implicated autoimmune diseases, is of
considerable importance for improving CD22-targeted therapies.
[0008] As a single agent, epratuzumab is well-tolerated, depleting
circulating B cells transiently in NHL patients (Leonard et al.,
2009, Cancer 113:2714-23), and by an average of 35% at 18 weeks in
SLE patients (Dorner et al., 2006, Arthritis Res Ther 8:R74). When
evaluated in vitro, epratuzumab displayed modest antibody-dependent
cellular cytotoxicity, but no complement-dependent cytotoxicity
(Carnahan et al., 2007, Mol Immunol 44:1331-41), and was shown to
inhibit the proliferation of B cells from patients with SLE, but
not from normal donors, under all culture conditions (Jacobi et
al., 2008, Ann Rheum Dis 67:450-57). Additional studies with B
cells from SLE patients indicated that (i) binding of epratuzumab
was particularly enhanced on CD2T compared to CD27.sup.+ B cells
(Daridon et al., 2010, Arthritis Res Ther 12:R204); (ii) a decrease
of CD62L and .beta.7 integrin and an increase of .beta.1 integrin
in the cell surface expression, as well as an enhanced migration
towards CXCL12, were noted for CD27.sup.- B cells preferentially
(Daridon et al., 2010); and (iii) the in vivo effects of
epratuzumab in SLE patients included an immediate and sustained (up
to 18 weeks) decrease in CD22 surface expression on circulating
CD2T and CD27.sup.+ B cells (Daridon et al., 2010). More recently,
pre-incubation with F(ab').sub.2 of epratuzumab was reported to
inhibit calcium mobilization and phosphorylation of Syk and
PLC.gamma.2 in normal human B cells after BCR stimulation (Sieger
et al., 2013, Arthritis Rheum 65:770-79), and the ability of
epratuzumab-based agents to effectively mediate Fc-dependent
trogocytosis of multiple B-cell surface markers by
Fc.gamma.R-bearing cells, was established (Rossi et al., 2013,
Blood 122:3020-29; Rossi et al., 2014, PLoS ONE 9:e98315).
[0009] In cell lines and xenografts of human Burkitt lymphoma,
soluble epratuzumab, although capable of phosphorylating CD22
(Carnahan et al., 2003, Clin Cancer Res 9:3982s-90s) and
translocating CD22 to lipid rafts (Qu et al, 2008, Blood
111:2211-19), as demonstrated in vitro, was not cytotoxic or
cytostatic (Carnahan et al., 2007, Mol Immunol 44:1331-41; Qu et
al., 2008), and displayed only minimal toxicity even when
crosslinked by goat anti-human IgG Fc.gamma. (GAH) (Carnahan et
al., 2007). On the other hand, in vitro cytotoxicity of epratuzumab
comparable to that achievable with anti-IgM (10 .mu.g/mL) could be
consistently demonstrated in Ramos and D1-1, a subclone of Daudi
selected for a high expression of membrane IgM (mIgM), when the
antibody was immobilized to plastic plates, or added in combination
with suboptimal amounts of anti-IgM (for example, 1 .mu.g/mL or
less) along with GAH (Carnahan et al., 2007). Despite all of this
knowledge, how epratuzumab kills or modulates normal and malignant
B cells in patients, and inhibits the growth of lymphoma lines in
vitro upon immobilization, remains poorly understood. A need exists
in the field for improved methods of use of anti-CD22 antibodies,
based on their mechanism(s) of action of anti-cancer and/or
anti-autoimmune disease activity.
SUMMARY
[0010] The present invention concerns compositions and methods of
use of antibodies against CD22. In preferred embodiments, use of
the antibodies provides extensive cross-linking of CD22 on B cells,
which in turn induces phosphorylation of CD22, CD79a and CD79b,
along with their translocation to lipid rafts, stabilization of
F-actin, phosphorylation of Lyn, ERKs and JNKs, generation of
reactive oxygen species (ROS), decrease in mitochondria membrane
potential (.DELTA..psi..sub.m), upregulation of pro-apoptotic Bax,
and downregulation of anti-apoptotic Bcl-xl and Mcl-1. These in
turn result in BCR signaling and/or caspase-dependent apoptosis.
Such mechanisms are of use for treating hematopoietic cancer,
B-cell related autoimmune disease and/or immune system dysfunction,
such as GVHD or organ transplant rejection.
[0011] The anti-CD22 antibody also induces trogocytosis of
BCR-related antigens, resulting in decreased levels of CD19, CD20,
CD21, CD22, CD79b, CD44, CD62L and .beta.7-integrin on the surface
of affected B cells. B cell antigens, particularly CD19, inhibit B
cell activation in response to T cell-dependent antigens and has a
therapeutic effect on autoimmune and immune dysfunction diseases,
which are mediated at least in part by B cell activation.
[0012] One example of a preferred anti-CD22 antibody is
epratuzumab, which induces trogocytosis without incurring direct
cytotoxicity to B cells, thus providing an unexpected and
substantial advantage in treating autoimmune diseases, such as
systemic lupus erythematosus (SLE), ANCA-associated vasculitides,
and other autoimmune diseases. However, other anti-CD22 antibodies
that may be used are publicly available and/or known in the art.
Such known and/or publicly available antibodies include, but are
not limited to, inotuzumab (Pfizer, Groton, Conn.), CAT-3888
(Cambridge Antibody Technology Group, Cambridge, England), CAT-8015
(Cambridge Antibody Technology Group, Cambridge, England), HB22.7
(Duke University, Durham, N.C.) and RFB4 (e.g., Invitrogen, Grand
Island, N.Y.; Santa Cruz Biotechnology, Santa Cruz, Calif.).
[0013] Exemplary autoimmune or immune dysfunction diseases include
acute immune thrombocytopenia, chronic immune thrombocytopenia,
dermatomyositis, Sydenham's chorea, myasthenia gravis, systemic
lupus erythematosus, lupus nephritis, rheumatic fever,
polyglandular syndromes, bullous pemphigoid, pemphigus vulgaris,
diabetes mellitus (e.g., juvenile diabetes), Henoch-Schonlein
purpura, post-streptococcal nephritis, erythema nodosum, Takayasu's
arteritis, ANCA-associated vasculitides, Addison's disease,
rheumatoid arthritis, multiple sclerosis, sarcoidosis, ulcerative
colitis, erythema multiforme, IgA nephropathy, polyarteritis
nodosa, ankylosing spondylitis, Goodpasture's syndrome,
thromboangitis obliterans, Sjogren's syndrome, primary biliary
cirrhosis, Hashimoto's thyroiditis, thyrotoxicosis, scleroderma,
chronic active hepatitis, polymyositis/dermatomyositis,
polychondritis, pemphigus vulgaris, Wegener's granulomatosis,
membranous nephropathy, amyotrophic lateral sclerosis, tabes
dorsalis, giant cell arteritis/polymyalgia, pernicious anemia,
rapidly progressive glomerulonephritis, psoriasis, fibrosing
alveolitis, graft-versus-host disease (GVHD), organ transplant
rejection, sepsis, septicemia and inflammation.
[0014] Exemplary hematopoietic cancers include non-Hodgkin's
lymphoma, B-cell acute and chronic lymphoid leukemias, Burkitt
lymphoma, Hodgkin's lymphoma, mantle cell lymphoma, hairy cell
leukemia, multiple myeloma and Waldenstrom's macroglobulinemia.
[0015] An antibody of use may be chimeric, humanized or human. The
use of chimeric antibodies is preferred to the parent murine
antibodies because they possess human antibody constant region
sequences and therefore do not elicit as strong a human anti-mouse
antibody (HAMA) response as murine antibodies. The use of humanized
antibodies is even more preferred, in order to further reduce the
possibility of inducing a HAMA reaction. Techniques for
humanization of murine antibodies by replacing murine framework and
constant region sequences with corresponding human antibody
framework and constant region sequences are well known in the art
and have been applied to numerous murine anti-cancer antibodies.
Antibody humanization may also involve the substitution of one or
more human framework amino acid residues with the corresponding
residues from the parent murine framework region sequences. As
discussed below, techniques for production of human antibodies are
also well known.
[0016] The antibody may also be multivalent, or multivalent and
multispecific. The antibody may include human constant regions of
IgG1, IgG2, IgG3, or IgG4. Preferably, the allotype of the antibody
may be selected to minimize host immunogenic response to the
administered antibody, as discussed in more detail below. A
preferred allotype is a non-G1m1 allotype (nG1m1), such as G1m3,
G1m3,1, G1m3,2 or G1m3,1,2. The non-G1m1 allotype is preferred for
decreased antibody immunoreactivity. Surprisingly, repeated
subcutaneous administration of concentrated nG1m1 antibody was not
found to induce significant immune response, despite the enhanced
immunogenicity of subcutaneous administration.
[0017] The anti-CD22 antibody, or antigen-binding fragments
thereof, may be administered as a naked antibody or fragment,
either alone or in combination with one or more therapeutic agents.
In other embodiments, the antibody or fragment thereof may be
conjugated to one or more therapeutic agents to form an
immunoconjugate. Therapeutic agents may be selected from the group
consisting of a drug, prodrug, immunomodulator, cytokine,
chemokine, pro-apoptotic agent, anti-angiogenic agent, tyrosine
kinase inhibitor, Bruton kinase inhibitor, sphingosine inhibitor,
enzyme, hormone, photoactive agent, siRNA and RNAi.
[0018] The drug to be used may be selected from the group
consisting of an anthracycline, a camptothecin, a tubulin
inhibitor, a maytansinoid, a calicheamycin, an auristatin, a
nitrogen mustard, an ethylenimine derivative, an alkyl sulfonate, a
nitrosourea, a triazene, a folic acid analog, a taxane, a COX-2
inhibitor, a pyrimidine analog, a purine analog, an antibiotic, an
enzyme inhibitor, an epipodophyllotoxin, a platinum coordination
complex, a vinca alkaloid, a substituted urea, a methyl hydrazine
derivative, an adrenocortical suppressant, a hormone antagonist, an
antimetabolite, an alkylating agent, an antimitotic, an
anti-angiogenic agent, a tyrosine kinase inhibitor, an mTOR
inhibitor, a heat shock protein (HSP90) inhibitor, a proteosome
inhibitor, an HDAC inhibitor, a pro-apoptotic agent, and a
combination thereof.
[0019] Specific drugs of use may be selected from the group
consisting of 5-fluorouracil, afatinib, aplidin, azaribine,
anastrozole, anthracyclines, axitinib, AVL-101, AVL-291,
bendamustine, bleomycin, bortezomib, bosutinib, bryostatin-1,
busulfan, calicheamycin, camptothecin, carboplatin,
10-hydroxycamptothecin, carmustine, celecoxib, chlorambucil,
cisplatinum, COX-2 inhibitors, irinotecan (CPT-11), SN-38,
carboplatin, cladribine, camptothecans, crizotinib,
cyclophosphamide, cytarabine, dacarbazine, dasatinib, dinaciclib,
docetaxel, dactinomycin, daunorubicin, DM1, DM3, DM4, doxorubicin,
2-pyrrolinodoxorubicine (2-PDox), a pro-drug form of 2-PDox
(pro-2-PDox), cyano-morpholino doxorubicin, doxorubicin
glucuronide, endostatin, epirubicin glucuronide, erlotinib,
estramustine, epidophyllotoxin, erlotinib, entinostat, estrogen
receptor binding agents, etoposide (VP16), etoposide glucuronide,
etoposide phosphate, exemestane, fingolimod, floxuridine (FUdR),
3',5'-O-dioleoyl-FudR (FUdR-dO), fludarabine, flutamide,
farnesyl-protein transferase inhibitors, flavopiridol,
fostamatinib, ganetespib, GDC-0834, GS-1101, gefitinib,
gemcitabine, hydroxyurea, ibrutinib, idarubicin, idelalisib,
ifosfamide, imatinib, lapatinib, lenolidamide, leucovorin, LFM-A13,
lomustine, mechlorethamine, melphalan, mercaptopurine,
6-mercaptopurine, methotrexate, mitoxantrone, mithramycin,
mitomycin, mitotane, monomethylauristatin F (MMAF),
monomethylauristatin D (MMAD), monomethylauristatin E (MMAE),
navelbine, neratinib, nilotinib, nitrosurea, olaparib, plicomycin,
procarbazine, paclitaxel, PCI-32765, pentostatin, PSI-341,
raloxifene, semustine, SN-38, sorafenib, streptozocin, SU11248,
sunitinib, tamoxifen, temazolomide, transplatinum, thalidomide,
thioguanine, thiotepa, teniposide, topotecan, uracil mustard,
vatalanib, vinorelbine, vinblastine, vincristine, vinca alkaloids
and ZD1839.
[0020] Immunomodulators of use may be selected from the group
consisting of erythropoietin, thrombopoietin, tumor necrosis
factor-.alpha. (TNF), granulocyte-colony stimulating factor
(G-CSF), granulocyte macrophage-colony stimulating factor (GM-CSF),
interferon-.alpha., interferon-.beta., interferon-.gamma., stem
cell growth factor designated "S1 factor", human growth hormone,
N-methionyl human growth hormone, bovine growth hormone,
parathyroid hormone, thyroxine, insulin, proinsulin, relaxin,
prorelaxin, follicle stimulating hormone (FSH), thyroid stimulating
hormone (TSH), luteinizing hormone (LH), hepatic growth factor,
prostaglandin, fibroblast growth factor, prolactin, placental
lactogen, mullerian-inhibiting substance, mouse
gonadotropin-associated peptide, inhibin, activin, vascular
endothelial growth factor, integrin, NGF-.beta., platelet-growth
factor, TGF-.alpha., TGF-.beta., insulin-like growth factor-I,
insulin-like growth factor-II, macrophage-CSF (M-CSF), IL-1,
IL-1.alpha., IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10,
IL-11, IL-12, IL-13, IL-14, IL-15, IL-16, IL-17, IL-18, IL-21,
angiostatin, thrombospondin, endostatin and lymphotoxin (LT).
[0021] Toxins of use may be selected from the group consisting of
ricin, abrin, alpha toxin, saporin, ribonuclease (RNase), DNase I,
Staphylococcal enterotoxin-A, pokeweed antiviral protein, gelonin,
diphtheria toxin, Pseudomonas exotoxin, and Pseudomonas
endotoxin.
[0022] A radionuclide of use may include .sup.14C, .sup.13N,
.sup.15O, .sup.32P, .sup.33P, .sup.47Sc, .sup.51Cr, .sup.57Co,
.sup.58Co, .sup.59Fe, .sup.62Cu, .sup.67Cu, .sup.67Ga, .sup.67Ga,
.sup.75Br, .sup.75Se, .sup.75Se, .sup.76Br, .sup.77As, .sup.77Br,
.sup.80mBr, .sup.89Sr, .sup.90Y, .sup.95Ru, .sup.97Ru, .sup.99Mo,
.sup.99mTc, .sup.103mRh, .sup.103Rh, .sup.105Rh, .sup.105Rh,
.sup.107Hg, .sup.109Pd, .sup.109Pt, .sup.111Ag, .sup.111In,
.sup.113mIn, .sup.119Sb, .sup.121mTe, .sup.122mTe, .sup.125I,
.sup.125mTe, .sup.126I, .sup.131I, .sup.133I, .sup.142Pr,
.sup.143Pr, .sup.149Pm, .sup.152Dy, .sup.153Sm, .sup.161Ho,
.sup.161Tb, .sup.165Tm, .sup.166Dy, .sup.166Ho, .sup.167Tm,
.sup.168Tm, .sup.169Er, .sup.169Yb, .sup.177Lu, .sup.186Re,
.sup.188Re, .sup.189mOs, .sup.189Re, .sup.192Ir, .sup.194Ir,
.sup.197Pt, .sup.198Au, .sup.199Au, .sup.199Au, .sup.201Tl,
.sup.203Hg, .sup.211At, .sup.211Bi, .sup.211Pb, .sup.212Pb,
.sup.212Pb, .sup.213Bi, .sup.215Po, .sup.217At, .sup.219Rn,
.sup.221Fr, .sup.223Ra, .sup.224Ac, .sup.225Ac, .sup.255Fm or
.sup.227Th.
[0023] Exemplary tyrosine kinase inhibitors include, but are not
limited to canertinib, dasatinib, erlotinib, gefitinib, imatinib,
lapatinib, leflunomide, nilotinib, pazopanib, semaxinib, sorafenib,
sunitinib, sutent and vatalanib. A specific class of tyrosine
kinase inhibitor is the Bruton tyrosine kinase inhibitor. Bruton
tyrosine kinase (Btk) has a well-defined role in B-cell
development. Bruton kinase inhibitors include, but are not limited
to, PCI-32765 (ibrutinib), PCI-45292, GDC-0834, LFM-A13 and
RN486.
[0024] These and other known therapeutic modalities may be used in
combination with the anti-CD22 antibodies disclosed herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The following drawings are provided to illustrate preferred
embodiments of the invention. However, the claimed subject matter
is in no way limited by the illustrative embodiments disclosed in
the drawings.
[0026] FIG. 1A. Evaluation of growth-inhibition and apoptosis in
D1-1 and Ramos cells. Cell viability determined by the MTS assay
after 4-day incubation for the Dried-I format of epratuzumab
(hLL2*) or labetuzumab (hMN-14*). Error bars represent standard
deviation (SD), where n=3. Significant differences compared to
untreated or nonspecific antibody are indicated with (P<0.005)
and # (P<0.05).
[0027] FIG. 1B. Evaluation of growth-inhibition and apoptosis in
D1-1 and Ramos cells. Cell viability determined by the MTS assay
after 4-day incubation for the Wet-I format of epratuzumab (hLL2)
or labetuzumab (hMN-14). Error bars represent standard deviation
(SD), where n=3. Significant differences compared to untreated or
nonspecific antibody are indicated with (P<0.005) and #
(P<0.05).
[0028] FIG. 1C. Evaluation of growth-inhibition and apoptosis in
D1-1 and Ramos cells. Apoptosis as determine by Annexin V staining
following the indicated treatments of D1-1 and Ramos cells for 24
and 48 h, respectively. Error bars represent standard deviation
(SD), where n=3. Significant differences compared to untreated or
nonspecific antibody are indicated with (P<0.005) and #
(P<0.05).
[0029] FIG. 1D. Evaluation of growth-inhibition and apoptosis in
D1-1 and Ramos cells. Plate-immobilized F(ab').sub.2 of epratuzumab
(hLL2 F(ab').sub.2*) effectively induced apoptosis (left panel) and
inhibited proliferation (right panel) in D1-1 cells as determined
by the annexin V assay at 24 h and the MTS assay after 4 days,
respectively. Error bars represent standard deviation (SD), where
n=3. Significant differences compared to untreated or nonspecific
antibody are indicated with (P<0.005) and # (P<0.05).
[0030] FIG. 2A. Cytotoxicity of epratuzumab in various formats to
Daudi cells. Epratuzumab presented as the Dried-I (hLL2*) or
Wet-III (hLL2+GAH+anti-IgM) format, right panel, but not the Wet-I
(hLL2) or Wet-IIB (hLL2+GAH) format, left panel, induced
dose-dependent cytotoxicity in Daudi cells, as measured by the MTS
assay.
[0031] FIG. 2B. Cytotoxicity of epratuzumab in various formats to
Daudi cells. The Dried-I format of epratuzumab (hLL2*) induced
apoptosis comparable to the positive control of anti-IgM as
determined by the Annexin V assay.
[0032] FIG. 2C. Cytotoxicity of epratuzumab in various formats to
Daudi cells. The Dried-I format and the Dried-II format, in which
soluble epratuzumab was added to a monolayer of HUV-EC, induced
apoptosis in Daudi cells to a similar extent (.about.50%).
[0033] FIG. 3A. Phosphorylation of CD79a, CD79b, CD22 and their
translocation into lipid rafts. Western blot analyses of
phosphorylated CD79a, CD79b, and CD22 in D1-1 cells treated for 2 h
with the Wet-I format of soluble (upper panel) or the Dried-I
format of immobilized (lower panel) antibodies, and
[0034] FIG. 3B. Phosphorylation of CD79a, CD79b, CD22 and their
translocation into lipid rafts. Western blot analyses of
phosphorylated CD79a, CD79b, and CD22 in D1-1 cells treated for 2 h
with various formats of soluble epratuzumab, including Wet-I (lane
4; hLL2, 7.5 .mu.g/mL), Wet-IIA (lane 5; hLL2, 7.5 .mu.g/mL; GAH,
10 .mu.g/mL), and Wet-III (lane 7; hLL2, 7.5 .mu.g/mL; GAH, 10
.mu.g/mL; anti-IgM, 1 .mu.g/mL). In lane 6, the amounts of anti-hFc
and anti-IgM were the same as those in lane 7, but hLL2 was too low
(10 ng/mL) to induce a notable effect.
[0035] FIG. 3C. Phosphorylation of CD79a, CD79b, CD22 and their
translocation into lipid rafts. CD22 was detected in the lipid
rafts (fractions 3-6) following treatment of D1-1 cells with
anti-IgM (10 .mu.g/mL) and both the Wet-I (hLL2, 20 .mu.g/mL) and
Dried-I (hLL2*, 20 .mu.g/mL) formats of epratuzumab.
[0036] FIG. 3D. CD79b was translocated to the lipid rafts
(fractions 4-7) by either anti-IgM (10 .mu.g/mL) or the Dried-I
format of epratuzumab (hLL2*, 20 .mu.g/mL), but not soluble
epratuzumab (hLL2).
[0037] FIG. 3E. Phosphorylation of CD79a, CD79b, CD22 and their
translocation into lipid rafts. Anti-IgM (lane 6) and epratuzumab
of the Dried-I (lane 3) or Wet-III (lane 4) format, but not the
Wet-I (lane 2) or Wet-IIA (lane 5) format, induced redistribution
of CD22, CD79a, and CD79b to the lipid rafts.
[0038] FIG. 4A. Phosphorylation of BCR-mediated signals, modulation
of MAP kinases, and evidence of caspase-dependent apoptosis. D1-1
cells were incubated with the Dried-I format of epratuzumab for the
indicated times and cell lysates probed for phosphorylated Lyn,
Syk, or PLC.gamma.2.
[0039] FIG. 4B. Phosphorylation of BCR-mediated signals, modulation
of MAP kinases, and evidence of caspase-dependent apoptosis. The
cell lysates of D1-1 cells obtained as described in the legend for
FIG. 4A were probed for phosphorylated ERKs and JNK.
[0040] FIG. 4C. Phosphorylation of BCR-mediated signals, modulation
of MAP kinases, and evidence of caspase-dependent apoptosis.
SP600125, a chemical inhibitor for JNK, protected D1-1 cells from
apoptosis induced by plate-immobilized epratuzumab.
[0041] FIG. 4D. Phosphorylation of BCR-mediated signals, modulation
of MAP kinases, and evidence of caspase-dependent apoptosis.
Western blot analysis of selective anti- and pro-apoptotic proteins
following treatment of D1-1 cells with plate-immobilized
epratuzumab for 24, 48 and 72 h. The untreated sample at 72 h is
shown.
[0042] FIG. 4E. Phosphorylation of BCR-mediated signals, modulation
of MAP kinases, and evidence of caspase-dependent apoptosis.
Plate-immobilized epratuzumab (hLL2*) induced cleavages of caspase
3, caspase 9 and PARP, which were evident at 48 and 72 h. The
untreated sample at 72 h is shown. (F) Z-VAD-fmk inhibited
apoptosis in D1-1 cells induced by plate-immobilized
epratuzumab.
[0043] FIG. 4F. Z-VAD-fmk inhibited apoptosis in D1-1 cells induced
by plate-immobilized epratuzumab (hLL2*).
[0044] FIG. 5A. Effect on .DELTA..psi..sub.m and ROS. Treatment of
D1-1 cells with the Dried-I format of epratuzumab induced a
decrease in .DELTA..psi..sub.m.
[0045] FIG. 5B. Effect on A .DELTA..psi..sub.m and ROS. Treatment
of Daudi cells with the Dried-II format also induced a decrease in
.DELTA..psi..sub.m, similar to that observed in D1-1 cells with the
Dried-I format.
[0046] FIG. 5C. Effect on .DELTA..psi..sub.m and ROS. Both the
Dried-I and the Dried-II formats of epratuzumab increased the
generation of ROS in Daudi cells.
[0047] FIG. 6A. Decrease in intracellular calcium release and
perturbation of actin dynamics. Pretreatment of Daudi cells with
soluble (Wet-I) or immobilized (Dried-I) epratuzumab for 1 h
reduced the mobilization of intracellular calcium ions following
stimulation with anti-IgM, but did not affect the subsequent entry
of extracellular calcium.
[0048] FIG. 6B. Decrease in intracellular calcium release and
perturbation of actin dynamics. The ligation of CD22 by
plate-immobilized epratuzumab stabilized the F-actin from
depolymerization by LatB.
[0049] FIG. 6C. Decrease in intracellular calcium release and
perturbation of actin dynamics. Before the addition of LatB (left
panel), F-actin was visualized by staining with rhodamin phalloidin
in untreated Daudi cells, as well as in cells pretreated with the
Dried-I format of epratuzumab (hLL2*), the isotype control of the
Dried-I format (hMN-14*), or the Wet-I format of epratuzumab
(hLL2). The addition of LatB (right panel) did not affect the
staining of F-actin in cells pretreated with hLL2*, but demolished
the staining of F-actin in the other three.
[0050] FIG. 7A. Schematics of proposed mechanism of
epratuzumab-mediated interaction of endothelial cells with
CD22-expressing B cells. CD22 can interact with CD22L (sialylated
glycoproteins) on the same (cis) or different cells (trans). To
induce the trans interaction, it is necessary to overcome the cis
interaction, which may be provided by non-ligand-blocking
epratuzumab. Because Daudi cells have a high levels of CD22L, the
binding of CD22 to (activated) endothelial cells are inhibited by
cis-binding. The ligation of hLL2 to CD22 is likely to break up the
cis-interaction and because hLL2 is not a blocking antibody, hLL2
may not interfere with the further binding of CD22 to the CD22L
expressed on activated endothelial cells. Thus hLL2 plays an
indirect role to facilitate an efficient binding of B cells to
endothelial cells, which mimics the direct binding of B cells to
immobilized hLL2.
[0051] FIG. 7B. Schematics of proposed mechanism of
epratuzumab-mediated interaction of endothelial cells with
CD22-expressing B cells. Epratuzumab enables the attachment of
CD22-expressing B cells to EC in the endothelium via the
trans-interaction of CD22 with CD22L.
[0052] FIG. 7C. Schematics of proposed mechanism of
epratuzumab-mediated interaction of endothelial cells with
CD22-expressing B cells. Epratuzumab links CD22-expressing B cells
to EC in the endothelium via the Fc-Fc.gamma.R binding.
[0053] FIG. 8. Location of lipid rafts. Untreated Daudi cells
(5.times.10.sup.7) were lysed in 1 mL of cell lysis buffer (Cell
Signaling) containing 1% Triton and 1% protease inhibitor cocktail
on ice for 30 min. The lysates were subjected to discontinuous
sucrose density gradient ultracentrifugation as described in the
Materials and Methods and 1-mL fractions were collected for
analysis of CD22, CD71, Lyn, and Ganglioside M1 (GM1), by
appropriate antibodies following SDS-PAGE. Fractions of 3-6 were
identified as lipid rafts by the dot blot analysis of GM1, a known
lipid raft marker. CD71, a non-lipid raft marker, was found in
fractions 7 and higher, as was CD22 in the absence of ligation by
epratuzumab. The distribution of Lyn to the lipid rafts was also
detected.
DETAILED DESCRIPTION
Definitions
[0054] In the description that follows, a number of terms are used
and the following definitions are provided to facilitate
understanding of the claimed subject matter. Terms that are not
expressly defined herein are used in accordance with their plain
and ordinary meanings.
[0055] Unless otherwise specified, a or an means "one or more."
[0056] The term about is used herein to mean plus or minus ten
percent (10%) of a value. For example, "about 100" refers to any
number between 90 and 110.
[0057] An antibody, as used herein, refers to a full-length (i.e.,
naturally occurring or formed by normal immunoglobulin gene
fragment recombinatorial processes) immunoglobulin molecule (e.g.,
an IgG antibody) or an antigen-binding portion of an immunoglobulin
molecule, such as an antibody fragment. An antibody or antibody
fragment may be conjugated or otherwise derivatized within the
scope of the claimed subject matter. Such antibodies include but
are not limited to IgG1, IgG2, IgG3, IgG4 (and IgG4 subforms), as
well as IgA isotypes. In preferred embodiments, antibodies and
antibody fragments are selected to bind to human antigens.
[0058] An antibody fragment is a portion of an antibody such as
F(ab').sub.2, F(ab).sub.2, Fab', Fab, Fv, scFv (single chain Fv),
single domain antibodies (DABs or VHHs) and the like, including the
half-molecules of IgG4 cited above (van der Neut Kolfschoten et al.
(Science 2007; 317(14 September):1554-1557). A commercially
available form of single domain antibody is referred to as a
nanobody (ABLYNX.RTM., Ghent, Belgium). Regardless of structure, an
antibody fragment of use binds with the same antigen that is
recognized by the intact antibody. The term "antibody fragment"
also includes synthetic or genetically engineered proteins that act
like an antibody by binding to a specific antigen to form a
complex. For example, antibody fragments include isolated fragments
consisting of the variable regions, such as the "Fv" fragments
consisting of the variable regions of the heavy and light chains,
recombinant single chain polypeptide molecules in which light and
heavy variable regions are connected by a peptide linker ("scFv
proteins"). The Fv fragments may be constructed in different ways
to yield multivalent and/or multispecific binding forms. In the
case of multivalent, they have more than one binding site against
the specific epitope, whereas with multispecific forms, more than
one epitope (either of the same antigen or against one antigen and
a different antigen) is bound.
[0059] A naked antibody is generally an entire antibody that is not
conjugated to a therapeutic agent. This is so because the Fc
portion of the antibody molecule provides effector or immunological
functions, such as complement fixation and ADCC (antibody-dependent
cell cytotoxicity), which set mechanisms into action that may
result in cell lysis. However, the Fc portion may not be required
for therapeutic function of the antibody, but rather other
mechanisms, such as apoptosis, anti-angiogenesis, anti-metastatic
activity, anti-adhesion activity, such as inhibition of heterotypic
or homotypic adhesion, and interference in signaling pathways, may
come into play and interfere with disease progression. Naked
antibodies include both polyclonal and monoclonal antibodies, and
fragments thereof, that include murine antibodies, as well as
certain recombinant antibodies, such as chimeric, humanized or
human antibodies and fragments thereof. As used herein, "naked" is
synonymous with "unconjugated," and means not linked or conjugated
to a therapeutic agent.
[0060] A chimeric antibody is a recombinant protein that contains
the variable domains of both the heavy and light antibody chains,
including the complementarity determining regions (CDRs) of an
antibody derived from one species, preferably a rodent antibody,
more preferably a murine antibody, while the constant domains of
the antibody molecule are derived from those of a human antibody.
For veterinary applications, the constant domains of the chimeric
antibody may be derived from that of other species, such as a
primate, cat or dog.
[0061] A humanized antibody is a recombinant protein in which the
CDRs from an antibody from one species; e.g., a murine antibody,
are transferred from the heavy and light variable chains of the
murine antibody into human heavy and light variable domains
(framework regions). The constant domains of the antibody molecule
are derived from those of a human antibody. In some cases, specific
residues of the framework region of the humanized antibody,
particularly those that are touching or close to the CDR sequences,
may be modified, for example replaced with the corresponding
residues from the original murine, rodent, subhuman primate, or
other antibody.
[0062] A human antibody is an antibody obtained, for example, from
transgenic mice that have been "engineered" to produce human
antibodies in response to antigenic challenge. In this technique,
elements of the human heavy and light chain loci are introduced
into strains of mice derived from embryonic stem cell lines that
contain targeted disruptions of the endogenous heavy chain and
light chain loci. The transgenic mice can synthesize human
antibodies specific for various antigens, and the mice can be used
to produce human antibody-secreting hybridomas. Methods for
obtaining human antibodies from transgenic mice are described by
Green et al., Nature Genet. 7:13 (1994), Lonberg et al., Nature
368:856 (1994), and Taylor et al., Int. Immun. 6:579 (1994). A
fully human antibody also can be constructed by genetic or
chromosomal transfection methods, as well as phage display
technology, all of which are known in the art. See for example,
McCafferty et al., Nature 348:552-553 (1990) for the production of
human antibodies and fragments thereof in vitro, from
immunoglobulin variable domain gene repertoires from unimmunized
donors. In this technique, antibody variable domain genes are
cloned in-frame into either a major or minor coat protein gene of a
filamentous bacteriophage, and displayed as functional antibody
fragments on the surface of the phage particle. Because the
filamentous particle contains a single-stranded DNA copy of the
phage genome, selections based on the functional properties of the
antibody also result in selection of the gene encoding the antibody
exhibiting those properties. In this way, the phage mimics some of
the properties of the B cell. Phage display can be performed in a
variety of formats, for their review, see e.g. Johnson and
Chiswell, Current Opinion in Structural Biology 3:5564-571 (1993).
Human antibodies may also be generated by in vitro activated B
cells. See U.S. Pat. Nos. 5,567,610 and 5,229,275, the Examples
section of each of which is incorporated herein by reference.
[0063] A therapeutic agent is a molecule or atom that is useful in
the treatment of a disease. Examples of therapeutic agents include,
but are not limited to, antibodies, antibody fragments, conjugates,
drugs, cytotoxic agents, proapoptotic agents, toxins, nucleases
(including DNAses and RNAses), hormones, immunomodulators,
chelators, boron compounds, photoactive agents or dyes,
radioisotopes or radionuclides, oligonucleotides, interference RNA,
peptides, anti-angiogenic agents, chemotherapeutic agents,
cyokines, chemokines, prodrugs, enzymes, binding proteins or
peptides or combinations thereof.
[0064] An immunoconjugate is an antibody, antibody fragment or
other antibody moiety conjugated to a therapeutic agent.
[0065] As used herein, the term antibody fusion protein is a
recombinantly-produced antigen-binding molecule in which one or
more natural antibodies, single-chain antibodies or antibody
fragments are linked to another moiety, such as a protein or
peptide, a toxin, a cytokine, a hormone, etc. In certain preferred
embodiments, the fusion protein may comprise two or more of the
same or different antibodies, antibody fragments or single-chain
antibodies fused together, which may bind to the same epitope,
different epitopes on the same antigen, or different antigens.
[0066] An immunomodulator is a therapeutic agent that when present,
alters, suppresses or stimulates the body's immune system.
Typically, an immunomodulator of use stimulates immune cells to
proliferate or become activated in an immune response cascade, such
as macrophages, dendritic cells, B-cells, and/or T-cells. An
example of an immunomodulator as described herein is a cytokine,
which is a soluble small protein of approximately 5-20 kDa that is
released by one cell population (e.g., primed T-lymphocytes) on
contact with specific antigens, and which acts as an intercellular
mediator between cells. As the skilled artisan will understand,
examples of cytokines include lymphokines, monokines, interleukins,
and several related signaling molecules, such as tumor necrosis
factor (TNF) and interferons. Chemokines are a subset of cytokines.
Certain interleukins and interferons are examples of cytokines that
stimulate T cell or other immune cell proliferation.
[0067] Trogocytosis Induced by Anti-CD22
[0068] In certain embodiments, the subject anti-CD22 antibody
induces trogocytosis of multiple surface markers, which include,
but are not limited to, CD19, CD21, CD20, CD22 and CD79b on normal,
lupus, and malignant B cells via monocytes, NK cells and
granulocytes. Preferably, the anti-CD22 antibody displays little or
negligible direct cytotoxicity to normal B cells based on an in
vitro cell proliferation assay that shows less than 20% growth
inhibition when compared with untreated control, yet reduces CD19,
CD21, CD20, CD22, and CD79b to 20% or more of the untreated control
via trogocytosis in the presence of peripheral blood mononuclear
cells (PBMCs) or purified Fc.gamma.R-positive cells, such as NK
cells, monocytes and granulocytes. A preferred anti-CD22 antibody
is epratuzumab, which induces trogocytosis without incurring direct
cytotoxicity to B cells, thus providing an unexpected and
substantial advantage in treating autoimmune diseases, such as
systemic lupus erythematosus (SLE), ANCA-associated vasculitides,
and other autoimmune diseases.
[0069] The trogocytosis induced by anti-CD22 antibody reduces
levels of regulators of antigen-specific B-cell receptor (BCR),
such as CD19, CD20, CD21, CD22 and CD79b on the surface of affected
B cells. Reduction in these BCR regulators, particularly CD19,
inhibits B cell activation in response to T cell-dependent antigens
and has a therapeutic effect on autoimmune and immune dysfunction
diseases, which are mediated at least in part by B cell activation.
The efficacy of anti-CD22 antibodies for therapeutic use in
autoimmune and/or immune dysfunction diseases is correlated with
the trogocytosis-mediated decrease in the levels of BCR regulators
on the cell surface, particularly that of CD19.
[0070] Antibodies against CD22 are known in the art and any such
known antibody might be used in the claimed compositions and
methods. An exemplary anti-CD22 antibody is hLL2 (epratuzumab),
disclosed for example in U.S. Pat. No. 5,789,554, the Examples
section of which is incorporated herein by reference. The hLL2
antibody is a humanized anti-CD22 antibody comprising light chain
CDR sequences CDR1 (KSSQSVLYSANHKYLA, SEQ ID NO:1), CDR2 (WASTRES,
SEQ ID NO:2), and CDR3 (HQYLSSWTF, SEQ ID NO:3) and the heavy chain
CDR sequences CDR1 (SYWLH, SEQ ID NO:4), CDR2 (YINPRNDYTEYNQNFKD,
SEQ ID NO:5), and CDR3 (RDITTFY, SEQ ID NO:6), along with framework
(FR) and constant region sequences of human antibodies. Other known
anti-CD22 antibodies of potential use include, but are not limited
to, inotuzumab (Pfizer, Groton, Conn.), CAT-3888 (Cambridge
Antibody Technology Group, Cambridge, England), CAT-8015 (Cambridge
Antibody Technology Group, Cambridge, England), HB22.7 (Duke
University, Durham, N.C.) and RFB4 (e.g., Invitrogen, Grand Island,
N.Y.; Santa Cruz Biotechnology, Santa Cruz, Calif.).
[0071] CD22 Masking
[0072] CD22 is an inhibitory coreceptor on the surface of B cells
that attenuates BCR signaling and thereby B cell activation
(Courtney et al., 2009, Proc Natl Acad Sci USA 106:2500-05). CD22
function is modulated by interaction with extracellular glycan
ligands, mediated through its N-terminal Ig domain (Collins et al.,
2006, J Immunol 177:2994-3003). The preferred ligand for CD22
consists of .alpha.2,6-linked sialic acid-bearing glycans (CD22L),
expressed on B and T cells (Lajaunias et al., 2003, Arthritis &
Rheumatism 48:1612-21). The extracellular domain of CD22 shows
sequence similarity with the Siglec (sialic acid-binding Ig-like
lectin) subgroup of the Ig superfamily and is implicated in
adhesion of B cells to various cell types, such as lymphocytes,
monocytes, erythrocytes and endothelial cells (Lajaunias et al.,
2003). It is generally accepted that binding to CD22 is blocked or
"masked" by various CD22L-containing glycoproteins (which include
CD22 itself, anti-IgM, CD45, etc.) located on the same cell (cis
interaction) (see, e.g., Collins et al., 2004, Proc Natl Acad Sci
USA 101:6104-09). CD22 that has been masked by cis interaction is
not available for binding to different cells (trans interaction),
such as T cells, endothelial cells, selected cancer cells, etc.
that also contain CD22L-glycoproteins (Collins et al., 2004). It
has been suggested that cis ligands are important modulators of the
activity of CD22 as a regulator of B cell signaling (Collins et
al., 2004). The trans interactions appear to be involved in B cell
interactions with other cell types, such as activation of T cells
in vitro (Collins et al., 2004). In mixed lymphocyte costimulatory
assays, antibodies that inhibited CD22 binding to CD22L also
inhibited T cell activation (Collins, 2004). Conversely, activation
of B cells is reported to result in unmasking of CD22, which
facilitates trans interactions.
[0073] hLL2 (epratuzumab) is a non-blocking anti-CD22 antibody,
i.e., one that does not directly interfere with binding of CD22 to
CD22L. The present disclosure indicates that exposure to
epratuzumab pulls CD22 away from its endogenous, cis-binding
ligands (such as BCR-IgM) and thus promotes its trans-interaction
with other cells that bear CD22L. However, this effect can only be
induced by extensive crosslinking of CD22 via immobilized hLL2 in
vitro or likely adhering to endothelium in vivo. In essence, there
are three levels of engaging CD22 by anti-CD22, bivalent,
multivalent (via anti-Fc), and extensive crosslinking (requiring
immobilization), which result in increasing perturbation of CD22,
BCR and actin cytoskeleton. Our data indicate that the in vitro
immobilization of epratuzumab on an artificial plate can be
mimicked by a monolayer of endothelial cells, which suggest that
unmasking of CD22 by epratuzumab or other non-blocking anti-CD22
antibodies are significant for in vivo therapeutic effect in
hematopoietic cancers and autoimmune diseases such as SLE.
[0074] Preparation of Monoclonal Antibodies
[0075] An antibody of use may be chimeric, humanized or human. The
use of chimeric antibodies is preferred to the parent murine
antibodies because they possess human antibody constant region
sequences and therefore do not elicit as strong a human anti-mouse
antibody (HAMA) response as murine antibodies. The use of humanized
antibodies is even more preferred, in order to further reduce the
possibility of inducing a HAMA reaction. Techniques for
humanization of murine antibodies by replacing murine framework and
constant region sequences with corresponding human antibody
framework and constant region sequences are well known in the art
and have been applied to numerous murine anti-cancer antibodies.
Antibody humanization may also involve the substitution of one or
more human framework amino acid residues with the corresponding
residues from the parent murine framework region sequences. As
discussed below, techniques for production of human antibodies are
also well known.
[0076] The compositions, formulations and methods described herein
may include monoclonal antibodies. Rodent monoclonal antibodies to
specific antigens may be obtained by methods known to those skilled
in the art. (See, e.g., Kohler and Milstein, Nature 256: 495
(1975), and Coligan et al. (eds.), CURRENT PROTOCOLS IN IMMUNOLOGY,
VOL. 1, pages 2.5.1-2.6.7 (John Wiley & Sons 1991)). General
techniques for cloning murine immunoglobulin variable domains have
been disclosed, for example, by the publication of Orlandi et al.,
Proc. Nat'l Acad. Sci. USA 86: 3833 (1989).
[0077] Chimeric Antibodies
[0078] A chimeric antibody is a recombinant protein that contains
the variable domains including the CDRs derived from one species of
animal, such as a rodent antibody, while the remainder of the
antibody molecule; i.e., the constant domains, is derived from a
human antibody. Techniques for constructing chimeric antibodies are
well known to those of skill in the art. As an example, Leung et
al., Hybridoma 13:469 (1994), disclose how they produced an LL2
chimera by combining DNA sequences encoding the V.sub.k and V.sub.H
domains of LL2 monoclonal antibody, an anti-CD22 antibody, with
respective human and IgG.sub.1 constant region domains. This
publication also provides the nucleotide sequences of the LL2 light
and heavy chain variable regions, V.sub.k and V.sub.H,
respectively.
[0079] Humanized Antibodies
[0080] A chimeric monoclonal antibody can be humanized by replacing
the sequences of the murine FR in the variable domains of the
chimeric antibody with one or more different human FR.
Specifically, mouse CDRs are transferred from heavy and light
variable chains of the mouse immunoglobulin into the corresponding
variable domains of a human antibody. As simply transferring mouse
CDRs into human FRs often results in a reduction or even loss of
antibody affinity, additional modification might be required in
order to restore the original affinity of the murine antibody. This
can be accomplished by the replacement of one or more some human
residues in the FR regions with their murine counterparts to obtain
an antibody that possesses good binding affinity to its epitope.
(See, e.g., Tempest et al., Biotechnology 9:266 (1991) and
Verhoeyen et al., Science 239: 1534 (1988)). Techniques for
producing humanized antibodies are disclosed, for example, by Jones
et al., Nature 321: 522 (1986), Riechmann et al., Nature 332: 323
(1988), Verhoeyen et al., Science 239: 1534 (1988), Carter et al.,
Proc. Nat'l Acad. Sci. USA 89: 4285 (1992), Sandhu, Crit. Rev.
Biotech. 12: 437 (1992), and Singer et al., J. Immun. 150: 2844
(1993).
[0081] Human Antibodies
[0082] A fully human antibody can be obtained from a transgenic
non-human animal. (See, e.g., Mendez et al., Nature Genetics, 15:
146-156, 1997; U.S. Pat. No. 5,633,425.) Methods for producing
fully human antibodies using either combinatorial approaches or
transgenic animals transformed with human immunoglobulin loci are
known in the art (e.g., Mancini et al., 2004, New Microbiol.
27:315-28; Conrad and Scheller, 2005, Comb. Chem. High Throughput
Screen. 8:117-26; Brekke and Loset, 2003, Curr. Opin. Pharmacol.
3:544-50; each incorporated herein by reference). Such fully human
antibodies are expected to exhibit even fewer side effects than
chimeric or humanized antibodies and to function in vivo as
essentially endogenous human antibodies. In certain embodiments,
the claimed methods and procedures may utilize human antibodies
produced by such techniques.
[0083] In one alternative, the phage display technique may be used
to generate human antibodies (e.g., Dantas-Barbosa et al., 2005,
Genet. Mol. Res. 4:126-40, incorporated herein by reference). Human
antibodies may be generated from normal humans or from humans that
exhibit a particular disease state, such as cancer (Dantas-Barbosa
et al., 2005). The advantage to constructing human antibodies from
a diseased individual is that the circulating antibody repertoire
may be biased towards antibodies against disease-associated
antigens.
[0084] In one non-limiting example of this methodology,
Dantas-Barbosa et al. (2005) constructed a phage display library of
human Fab antibody fragments from osteosarcoma patients. Generally,
total RNA was obtained from circulating blood lymphocytes (Id.).
Recombinant Fab were cloned from the .mu., .gamma. and .kappa.
chain antibody repertoires and inserted into a phage display
library (Id.). RNAs were converted to cDNAs and used to make Fab
cDNA libraries using specific primers against the heavy and light
chain immunoglobulin sequences (Marks et al., 1991, J Mol. Biol.
222:581-97). Library construction was performed according to
Andris-Widhopf et al. (2000, In: Phage Display Laboratory Manual,
Barbas et al. (eds), 1.sup.st edition, Cold Spring Harbor
Laboratory Press, Cold Spring Harbor, N.Y. pp. 9.1 to 9.22,
incorporated herein by reference). The final Fab fragments were
digested with restriction endonucleases and inserted into the
bacteriophage genome to make the phage display library. Such
libraries may be screened by standard phage display methods. The
skilled artisan will realize that this technique is exemplary only
and any known method for making and screening human antibodies or
antibody fragments by phage display may be utilized.
[0085] In another alternative, transgenic animals that have been
genetically engineered to produce human antibodies may be used to
generate antibodies against essentially any immunogenic target,
using standard immunization protocols as discussed above. Methods
for obtaining human antibodies from transgenic mice are described
by Green et al., Nature Genet. 7:13 (1994), Lonberg et al., Nature
368:856 (1994), and Taylor et al., Int. Immun. 6:579 (1994). A
non-limiting example of such a system is the XenoMouse.RTM. (e.g.,
Green et al., 1999, J. Immunol. Methods 231:11-23, incorporated
herein by reference) from Abgenix (Fremont, Calif.). In the
XenoMouse.RTM. and similar animals, the mouse antibody genes have
been inactivated and replaced by functional human antibody genes,
while the remainder of the mouse immune system remains intact.
[0086] The XenoMouse.RTM. was transformed with germline-configured
YACs (yeast artificial chromosomes) that contained portions of the
human IgH and Ig kappa loci, including the majority of the variable
region sequences, along accessory genes and regulatory sequences.
The human variable region repertoire may be used to generate
antibody producing B cells, which may be processed into hybridomas
by known techniques. A XenoMouse.RTM. immunized with a target
antigen will produce human antibodies by the normal immune
response, which may be harvested and/or produced by standard
techniques discussed above. A variety of strains of XenoMouse.RTM.
are available, each of which is capable of producing a different
class of antibody. Transgenically produced human antibodies have
been shown to have therapeutic potential, while retaining the
pharmacokinetic properties of normal human antibodies (Green et
al., 1999). The skilled artisan will realize that the claimed
compositions and methods are not limited to use of the
XenoMouse.RTM. system but may utilize any transgenic animal that
has been genetically engineered to produce human antibodies.
[0087] Antibody Cloning and Production
[0088] Various techniques, such as production of chimeric or
humanized antibodies, may involve procedures of antibody cloning
and construction. The antigen-binding V.kappa. (variable light
chain) and V.sub.H (variable heavy chain) sequences for an antibody
of interest may be obtained by a variety of molecular cloning
procedures, such as RT-PCR, 5'-RACE, and cDNA library screening.
The V genes of an antibody from a cell that expresses a murine
antibody can be cloned by PCR amplification and sequenced. To
confirm their authenticity, the cloned V.sub.L and V.sub.H genes
can be expressed in cell culture as a chimeric Ab as described by
Orlandi et al., (Proc. Natl. Acad. Sci., USA, 86: 3833 (1989)).
Based on the V gene sequences, a humanized antibody can then be
designed and constructed as described by Leung et al. (Mol.
Immunol., 32: 1413 (1995)).
[0089] cDNA can be prepared from any known hybridoma line or
transfected cell line producing a murine antibody by general
molecular cloning techniques (Sambrook et al., Molecular Cloning, A
laboratory manual, 2.sup.nd Ed (1989)). The V.kappa. sequence for
the antibody may be amplified using the primers VK1BACK and VK1FOR
(Orlandi et al., 1989) or the extended primer set described by
Leung et al. (BioTechniques, 15: 286 (1993)). The V.sub.H sequences
can be amplified using the primer pair VH1BACK/VH1FOR (Orlandi et
al., 1989) or the primers annealing to the constant region of
murine IgG described by Leung et al. (Hybridoma, 13:469 (1994)).
Humanized V genes can be constructed by a combination of long
oligonucleotide template syntheses and PCR amplification as
described by Leung et al. (Mol. Immunol., 32: 1413 (1995)).
[0090] PCR products for V.kappa. can be subcloned into a staging
vector, such as a pBR327-based staging vector, VKpBR, that contains
an Ig promoter, a signal peptide sequence and convenient
restriction sites. PCR products for V.sub.H can be subcloned into a
similar staging vector, such as the pBluescript-based VHpBS.
Expression cassettes containing the V.kappa. and V.sub.H sequences
together with the promoter and signal peptide sequences can be
excised from VKpBR and VHpBS and ligated into appropriate
expression vectors, such as pKh and pG1g, respectively (Leung et
al., Hybridoma, 13:469 (1994)). The expression vectors can be
co-transfected into an appropriate cell and supernatant fluids
monitored for production of a chimeric, humanized or human
antibody. Alternatively, the V.kappa. and V.sub.H expression
cassettes can be excised and subcloned into a single expression
vector, such as pdHL2, as described by Gillies et al. (J. Immunol.
Methods 125:191 (1989) and also shown in Losman et al., Cancer,
80:2660 (1997)).
[0091] In an alternative embodiment, expression vectors may be
transfected into host cells that have been pre-adapted for
transfection, growth and expression in serum-free medium. Exemplary
cell lines that may be used include the Sp/EEE, Sp/ESF and Sp/ESF-X
cell lines (see, e.g., U.S. Pat. Nos. 7,531,327; 7,537,930 and
7,608,425; the Examples section of each of which is incorporated
herein by reference). These exemplary cell lines are based on the
Sp2/0 myeloma cell line, transfected with a mutant Bcl-EEE gene,
exposed to methotrexate to amplify transfected gene sequences and
pre-adapted to serum-free cell line for protein expression.
[0092] Antibody Allotypes
[0093] Immunogenicity of therapeutic antibodies is associated with
increased risk of infusion reactions and decreased duration of
therapeutic response (Baert et al., 2003, N Engl J Med 348:602-08).
The extent to which therapeutic antibodies induce an immune
response in the host may be determined in part by the allotype of
the antibody (Stickler et al., 2011, Genes and Immunity 12:213-21).
Antibody allotype is related to amino acid sequence variations at
specific locations in the constant region sequences of the
antibody. The allotypes of IgG antibodies containing a heavy chain
.gamma.-type constant region are designated as Gm allotypes (1976,
J Immunol 117:1056-59).
[0094] For the common IgG1 human antibodies, the most prevalent
allotype is G1m1 (Stickler et al., 2011, Genes and Immunity
12:213-21). However, the G1m3 allotype also occurs frequently in
Caucasians (Id.). It has been reported that G1m1 antibodies contain
allotypic sequences that tend to induce an immune response when
administered to non-G1m1 (nG1m1) recipients, such as G1m3 patients
(Id.). Non-G1m1 allotype antibodies are not as immunogenic when
administered to G1m1 patients (Id.).
[0095] The human G1m1 allotype comprises the amino acids aspartic
acid at Kabat position 356 and leucine at Kabat position 358 in the
CH3 sequence of the heavy chain IgG1. The nG1m1 allotype comprises
the amino acids glutamic acid at Kabat position 356 and methionine
at Kabat position 358. Both G1m1 and nG1m1 allotypes comprise a
glutamic acid residue at Kabat position 357 and the allotypes are
sometimes referred to as DEL and EEM allotypes. A non-limiting
example of the heavy chain constant region sequences for G1m1 and
nG1m1 allotype antibodies is shown for the exemplary antibodies
rituximab (SEQ ID NO:8) and veltuzumab (SEQ ID NO:7).
TABLE-US-00001 Veltuzumab heavy chain constant region sequence (SEQ
ID NO: 7) ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGV
HTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEP
KSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVS
HEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGK
EYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTC
LVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRW
QQGNVFSCSVMHEALHNHYTQKSLSLSPGK Rituximab heavy chain constant
region sequence (SEQ ID NO: 8)
ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGV
HTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKAEP
KSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVS
HEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGK
EYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTC
LVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRW
QQGNVFSCSVMHEALHNHYTQKSLSLSPGK
[0096] Jefferis and Lefranc (2009, mAbs 1:1-7) reviewed sequence
variations characteristic of IgG allotypes and their effect on
immunogenicity. They reported that the G1m3 allotype is
characterized by an arginine residue at Kabat position 214,
compared to a lysine residue at Kabat 214 in the G1m17 allotype.
The nG1m1,2 allotype was characterized by glutamic acid at Kabat
position 356, methionine at Kabat position 358 and alanine at Kabat
position 431. The G1m1,2 allotype was characterized by aspartic
acid at Kabat position 356, leucine at Kabat position 358 and
glycine at Kabat position 431. In addition to heavy chain constant
region sequence variants, Jefferis and Lefranc (2009) reported
allotypic variants in the kappa light chain constant region, with
the Km1 allotype characterized by valine at Kabat position 153 and
leucine at Kabat position 191, the Km1,2 allotype by alanine at
Kabat position 153 and leucine at Kabat position 191, and the Km3
allotype characterized by alanine at Kabat position 153 and valine
at Kabat position 191.
[0097] With regard to therapeutic antibodies, veltuzumab and
rituximab are, respectively, humanized and chimeric IgG1 antibodies
against CD20, of use for therapy of a wide variety of hematological
malignancies and/or autoimmune diseases. Table 1 compares the
allotype sequences of rituximab vs. veltuzumab. As shown in Table
1, rituximab (G1m17,1) is a DEL allotype IgG1, with an additional
sequence variation at Kabat position 214 (heavy chain CH1) of
lysine in rituximab vs. arginine in veltuzumab. It has been
reported that veltuzumab is less immunogenic in subjects than
rituximab (see, e.g., Morchhauser et al., 2009, J Clin Oncol
27:3346-53; Goldenberg et al., 2009, Blood 113:1062-70; Robak &
Robak, 2011, BioDrugs 25:13-25), an effect that has been attributed
to the difference between humanized and chimeric antibodies.
However, the difference in allotypes between the EEM and DEL
allotypes likely also accounts for the lower immunogenicity of
veltuzumab.
TABLE-US-00002 TABLE 1 Allotypes of Rituximab vs. Veltuzumab Heavy
chain position and associated allotypes Complete 214 356/358 431
allotype (allotype) (allotype) (allotype) Rituximab G1m17,1 K 17
D/L 1 A -- Veltuzumab G1m3 R 3 E/M -- A --
[0098] In order to reduce the immunogenicity of therapeutic
antibodies in individuals of nG1m1 genotype, it is desirable to
select the allotype of the antibody to correspond to the G1m3
allotype, characterized by arginine at Kabat 214, and the nG1m1,2
null-allotype, characterized by glutamic acid at Kabat position
356, methionine at Kabat position 358 and alanine at Kabat position
431. Surprisingly, it was found that repeated subcutaneous
administration of G1m3 antibodies over a long period of time did
not result in a significant immune response. In alternative
embodiments, the human IgG4 heavy chain in common with the G1m3
allotype has arginine at Kabat 214, glutamic acid at Kabat 356,
methionine at Kabat 359 and alanine at Kabat 431. Since
immunogenicity appears to relate at least in part to the residues
at those locations, use of the human IgG4 heavy chain constant
region sequence for therapeutic antibodies is also a preferred
embodiment. Combinations of G1m3 IgG1 antibodies with IgG4
antibodies may also be of use for therapeutic administration.
[0099] Known Antibodies
[0100] In various embodiments, the claimed methods and compositions
may utilize any of a variety of antibodies known in the art. For
example, therapeutic use of anti-CD22 antibodies may be
supplemented with one or more antibodies against other
disease-associated antigens. Antibodies of use may be commercially
obtained from a number of known sources. For example, a variety of
antibody secreting hybridoma lines are available from the American
Type Culture Collection (ATCC, Manassas, Va.). A large number of
antibodies against various disease targets, including but not
limited to tumor-associated antigens, have been deposited at the
ATCC and/or have published variable region sequences and are
available for use in the claimed methods and compositions. See,
e.g., U.S. Pat. Nos. 7,312,318; 7,282,567; 7,151,164; 7,074,403;
7,060,802; 7,056,509; 7,049,060; 7,045,132; 7,041,803; 7,041,802;
7,041,293; 7,038,018; 7,037,498; 7,012,133; 7,001,598; 6,998,468;
6,994,976; 6,994,852; 6,989,241; 6,974,863; 6,965,018; 6,964,854;
6,962,981; 6,962,813; 6,956,107; 6,951,924; 6,949,244; 6,946,129;
6,943,020; 6,939,547; 6,921,645; 6,921,645; 6,921,533; 6,919,433;
6,919,078; 6,916,475; 6,905,681; 6,899,879; 6,893,625; 6,887,468;
6,887,466; 6,884,594; 6,881,405; 6,878,812; 6,875,580; 6,872,568;
6,867,006; 6,864,062; 6,861,511; 6,861,227; 6,861,226; 6,838,282;
6,835,549; 6,835,370; 6,824,780; 6,824,778; 6,812,206; 6,793,924;
6,783,758; 6,770,450; 6,767,711; 6,764,688; 6,764,681; 6,764,679;
6,743,898; 6,733,981; 6,730,307; 6,720,155; 6,716,966; 6,709,653;
6,693,176; 6,692,908; 6,689,607; 6,689,362; 6,689,355; 6,682,737;
6,682,736; 6,682,734; 6,673,344; 6,653,104; 6,652,852; 6,635,482;
6,630,144; 6,610,833; 6,610,294; 6,605,441; 6,605,279; 6,596,852;
6,592,868; 6,576,745; 6,572,856; 6,566,076; 6,562,618; 6,545,130;
6,544,749; 6,534,058; 6,528,625; 6,528,269; 6,521,227; 6,518,404;
6,511,665; 6,491,915; 6,488,930; 6,482,598; 6,482,408; 6,479,247;
6,468,531; 6,468,529; 6,465,173; 6,461,823; 6,458,356; 6,455,044;
6,455,040, 6,451,310; 6,444,206; 6,441,143; 6,432,404; 6,432,402;
6,419,928; 6,413,726; 6,406,694; 6,403,770; 6,403,091; 6,395,276;
6,395,274; 6,387,350; 6,383,759; 6,383,484; 6,376,654; 6,372,215;
6,359,126; 6,355,481; 6,355,444; 6,355,245; 6,355,244; 6,346,246;
6,344,198; 6,340,571; 6,340,459; 6,331,175; 6,306,393; 6,254,868;
6,187,287; 6,183,744; 6,129,914; 6,120,767; 6,096,289; 6,077,499;
5,922,302; 5,874,540; 5,814,440; 5,798,229; 5,789,554; 5,776,456;
5,736,119; 5,716,595; 5,677,136; 5,587,459; 5,443,953, 5,525,338,
the Examples section of each of which is incorporated herein by
reference. These are exemplary only and a wide variety of other
antibodies and their hybridomas are known in the art. The skilled
artisan will realize that antibody sequences or antibody-secreting
hybridomas against almost any disease-associated antigen may be
obtained by a simple search of the ATCC, NCBI and/or USPTO
databases for antibodies against a selected disease-associated
target of interest. The antigen binding domains of the cloned
antibodies may be amplified, excised, ligated into an expression
vector, transfected into an adapted host cell and used for protein
production, using standard techniques well known in the art (see,
e.g., U.S. Pat. Nos. 7,531,327; 7,537,930; 7,608,425 and 7,785,880,
the Examples section of each of which is incorporated herein by
reference).
[0101] Particular antibodies that may be of use for therapy of
cancer within the scope of the claimed methods and compositions
include, but are not limited to, LL1 (anti-CD74), LL2 and RFB4
(anti-CD22), RS7 (anti-epithelial glycoprotein-1 (EGP-1)), PAM4 and
KC4 (both anti-mucin), MN-14 (anti-carcinoembryonic antigen (CEA,
also known as CD66e), MN-15 (anti-CEACAM6), Mu-9
(anti-colon-specific antigen-p), Immu 31 (an
anti-alpha-fetoprotein), TAG-72 (e.g., CC49), R1 (anti-IGF-1R), Tn,
J591 or HuJ591 (anti-PSMA (prostate-specific membrane antigen),
AB-PG1-XG1-026 (anti-PSMA dimer), D2/B (anti-PSMA), G250
(anti-carbonic anhydrase IX), hL243 (anti-HLA-DR), alemtuzumab
(anti-CD52), bevacizumab (anti-VEGF), cetuximab (anti-EGFR),
gemtuzumab (anti-CD33), ibritumomab (anti-CD20), panitumumab
(anti-EGFR), rituximab (anti-CD20), tositumomab (anti-CD20), GA101
(anti-CD20; obinutuzumab) and trastuzumab (anti-ErbB2). Such
antibodies are known in the art (e.g., U.S. Pat. Nos. 5,686,072;
5,874,540; 6,107,090; 6,183,744; 6,306,393; 6,653,104; 6,730,300;
6,899,864; 6,926,893; 6,962,702; 7,074,403; 7,230,084; 7,238,785;
7,238,786; 7,256,004; 7,282,567; 7,300,655; 7,312,318; 7,585,491;
7,612,180; 7,642,239; and U.S. Patent Application Publ. No.
20040202666 (now abandoned); 20050271671; and 20060193865; the
Examples section of each incorporated herein by reference.)
Specific known antibodies of use include hPAM4 (U.S. Pat. No.
7,282,567), hA20 (U.S. Pat. No. 7,151,164), hA19 (U.S. Pat. No.
7,109,304), hIMMU31 (U.S. Pat. No. 7,300,655), hLL1 (U.S. Pat. No.
7,312,318,), hLL2 (U.S. Pat. No. 5,789,554), hMu-9 (U.S. Pat. No.
7,387,772), hL243 (U.S. Pat. No. 7,612,180), hMN-14 (U.S. Pat. No.
6,676,924), hMN-15 (U.S. Pat. No. 7,541,440), hR1 (U.S. patent
application Ser. No. 12/772,645), hRS7 (U.S. Pat. No. 7,238,785),
hMN-3 (U.S. Pat. No. 7,541,440), AB-PG1-XG1-026 (U.S. patent
application Ser. No. 11/983,372, deposited as ATCC PTA-4405 and
PTA-4406) and D2/B (WO 2009/130575), the text of each recited
patent or application is incorporated herein by reference with
respect to the Figures and Examples sections.
[0102] Other antibodies of use for therapy of immune dysregulatory
or autoimmune disease include, but are not limited to, anti-B-cell
antibodies such as veltuzumab, epratuzumab, milatuzumab or hL243;
tocilizumab (anti-IL-6 receptor); basiliximab (anti-CD25);
daclizumab (anti-CD25); efalizumab (anti-CD11a); muromonab-CD3
(anti-CD3 receptor); OKT3 (anti-CDR3); anti-CD40L (UCB, Brussels,
Belgium); natalizumab (anti-.alpha.4 integrin) and omalizumab
(anti-IgE).
[0103] Antibody Fragments
[0104] Antibody fragments which recognize specific epitopes can be
generated by known techniques. The antibody fragments are antigen
binding portions of an antibody, such as F(ab).sub.2, Fab', Fab,
Fv, scFv and the like. Other antibody fragments include, but are
not limited to: the F(ab').sub.2 fragments which can be produced by
pepsin digestion of the antibody molecule and the Fab' fragments,
which can be generated by reducing disulfide bridges of the
F(ab').sub.2 fragments. Alternatively, Fab' expression libraries
can be constructed (Huse et al., 1989, Science, 246:1274-1281) to
allow rapid and easy identification of monoclonal Fab' fragments
with the desired specificity.
[0105] A single chain Fv molecule (scFv) comprises a VL domain and
a VH domain. The VL and VH domains associate to form a target
binding site. These two domains are further covalently linked by a
peptide linker (L). Methods for making scFv molecules and designing
suitable peptide linkers are disclosed in U.S. Pat. No. 4,704,692,
U.S. Pat. No. 4,946,778, R. Raag and M. Whitlow, "Single Chain
Fvs." FASEB Vol 9:73-80 (1995) and R. E. Bird and B. W. Walker,
"Single Chain Antibody Variable Regions," TIBTECH, Vol 9: 132-137
(1991).
[0106] An antibody fragment can be prepared by known methods, for
example, as disclosed by Goldenberg, U.S. Pat. Nos. 4,036,945 and
4,331,647 and references contained therein. Also, see Nisonoff et
al., Arch Biochem. Biophys. 89: 230 (1960); Porter, Biochem. J. 73:
119 (1959), Edelman et al., in METHODS IN ENZYMOLOGY VOL. 1, page
422 (Academic Press 1967), and Coligan at pages 2.8.1-2.8.10 and
2.10.-2.10.4.
[0107] A single complementarity-determining region (CDR) is a
segment of the variable region of an antibody that is complementary
in structure to the epitope to which the antibody binds and is more
variable than the rest of the variable region. Accordingly, a CDR
is sometimes referred to as hypervariable region. A variable region
comprises three CDRs. CDR peptides can be obtained by constructing
genes encoding the CDR of an antibody of interest. Such genes are
prepared, for example, by using the polymerase chain reaction to
synthesize the variable region from RNA of antibody-producing
cells. (See, e.g., Larrick et al., Methods: A Companion to Methods
in Enzymology 2: 106 (1991); Courtenay-Luck, "Genetic Manipulation
of Monoclonal Antibodies," in MONOCLONAL ANTIBODIES: PRODUCTION,
ENGINEERING AND CLINICAL APPLICATION, Ritter et al. (eds.), pages
166-179 (Cambridge University Press 1995); and Ward et al.,
"Genetic Manipulation and Expression of Antibodies," in MONOCLONAL
ANTIBODIES: PRINCIPLES AND APPLICATIONS, Birch et al., (eds.),
pages 137-185 (Wiley-Liss, Inc. 1995).
[0108] Another form of an antibody fragment is a single-domain
antibody (dAb), sometimes referred to as a single chain antibody.
Techniques for producing single-domain antibodies are well known in
the art (see, e.g., Cossins et al., Protein Expression and
Purification, 2007, 51:253-59; Shuntao et al., Molec Immunol 2006,
43:1912-19; Tanha et al., J. Biol. Chem. 2001, 276:24774-780).
[0109] In certain embodiments, the sequences of antibodies, such as
the Fc portions of antibodies, may be varied to optimize the
physiological characteristics of the conjugates, such as the
half-life in serum. Methods of substituting amino acid sequences in
proteins are widely known in the art, such as by site-directed
mutagenesis (e.g. Sambrook et al., Molecular Cloning, A laboratory
manual, 2.sup.nd Ed, 1989). In preferred embodiments, the variation
may involve the addition or removal of one or more glycosylation
sites in the Fc sequence (e.g., U.S. Pat. No. 6,254,868, the
Examples section of which is incorporated herein by reference). In
other preferred embodiments, specific amino acid substitutions in
the Fc sequence may be made (e.g., Hornick et al., 2000, J Nucl Med
41:355-62; Hinton et al., 2006, J Immunol 176:346-56; Petkova et
al. 2006, Int Immunol 18:1759-69; U.S. Pat. No. 7,217,797; Hwang
and Foote, 2005, Methods 36:3-10; Clark, 2000, Immunol Today
21:397-402; J Immunol 1976 117:1056-60; Ellison et al., 1982, Nucl
Acids Res 13:4071-79; Stickler et al., 2011, Genes and Immunity
12:213-21).
[0110] Multispecific and Multivalent Antibodies
[0111] Methods for producing bispecific antibodies include
engineered recombinant antibodies which have additional cysteine
residues so that they crosslink more strongly than the more common
immunoglobulin isotypes. (See, e.g., FitzGerald et al, Protein Eng.
10(10):1221-1225, (1997)). Another approach is to engineer
recombinant fusion proteins linking two or more different
single-chain antibody or antibody fragment segments with the needed
dual specificities. (See, e.g., Coloma et al., Nature Biotech.
15:159-163, (1997)). A variety of bispecific antibodies can be
produced using molecular engineering. In one form, the bispecific
antibody may consist of, for example, an scFv with a single binding
site for one antigen and a Fab fragment with a single binding site
for a second antigen. In another form, the bispecific antibody may
consist of, for example, an IgG with two binding sites for one
antigen and two scFv with two binding sites for a second antigen.
In alternative embodiments, multispecific and/or multivalent
antibodies may be produced as DOCK-AND-LOCK.RTM. (DNL.RTM.)
complexes as described below. Extensive cross-linking of CD22 may
be induced, for example, by administration of bispecific or
multispecific antibodies with multiple binding sites for CD22.
[0112] In certain embodiments, the anti-CD22 antibody may be
administered to a patient as part of a combination of antibodies.
Bispecific antibodies are preferred to administration of
combinations of separate antibodies, due to cost and convenience.
However, where combinations of separate antibodies provide improved
safety or efficacy, the combination may be utilized. The antibodies
may bind to different epitopes of the same antigen or to different
antigens. Preferably, the antigens are selected from the group
consisting of BCL-1, BCL-2, BCL-6, CD1a, CD2, CD3, CD4, CD S, CD7,
CD8, CD10, CD11b, CD11c, CD13, CD14, CD15, CD16, CD19, CD20, CD21,
CD22, CD23, CD25, CD33, CD34, CD38, CD40, CD40L, CD41a, CD43, CD45,
CD55, CD56, CCD57, CD59, CD64, CD71, CD79a, CD79b, CD117, CD138,
FMC-7 and HLA-DR. However, antibodies against other antigens of use
for therapy of cancer, autoimmune diseases or immune dysfunction
diseases are known in the art, as discussed below, and antibodies
against any such disease-associated antigen known in the art may be
utilized.
[0113] Dock-and-Lock.RTM. (DNL.RTM.)
[0114] In preferred embodiments, a bivalent or multivalent antibody
is formed as a DOCK-AND-LOCK.RTM. (DNL.RTM.) complex (see, e.g.,
U.S. Pat. Nos. 7,521,056; 7,527,787; 7,534,866; 7,550,143 and
7,666,400, the Examples section of each of which is incorporated
herein by reference.) Generally, the technique takes advantage of
the specific and high-affinity binding interactions that occur
between a dimerization and docking domain (DDD) sequence of the
regulatory (R) subunits of cAMP-dependent protein kinase (PKA) and
an anchor domain (AD) sequence derived from any of a variety of
AKAP proteins (Baillie et al., FEBS Letters. 2005; 579: 3264. Wong
and Scott, Nat. Rev. Mol. Cell Biol. 2004; 5: 959). The DDD and AD
peptides may be attached to any protein, peptide or other molecule.
Because the DDD sequences spontaneously dimerize and bind to the AD
sequence, the technique allows the formation of complexes between
any selected molecules that may be attached to DDD or AD
sequences.
[0115] Although the standard DNL.RTM. complex comprises a trimer
with two DDD-linked molecules attached to one AD-linked molecule,
variations in complex structure allow the formation of dimers,
trimers, tetramers, pentamers, hexamers and other multimers. In
some embodiments, the DNL.RTM. complex may comprise two or more
antibodies, antibody fragments or fusion proteins which bind to the
same antigenic determinant or to two or more different antigens.
The DNL.RTM. complex may also comprise one or more other effectors,
such as proteins, peptides, immunomodulators, cytokines,
interleukins, interferons, binding proteins, peptide ligands,
carrier proteins, toxins, ribonucleases such as onconase,
inhibitory oligonucleotides such as siRNA, antigens or
xenoantigens, polymers such as PEG, enzymes, therapeutic agents,
hormones, cytotoxic agents, anti-angiogenic agents, pro-apoptotic
agents or any other molecule or aggregate.
[0116] PKA, which plays a central role in one of the best studied
signal transduction pathways triggered by the binding of the second
messenger cAMP to the R subunits, was first isolated from rabbit
skeletal muscle in 1968 (Walsh et al., J. Biol. Chem. 1968;
243:3763). The structure of the holoenzyme consists of two
catalytic subunits held in an inactive form by the R subunits
(Taylor, J. Biol. Chem. 1989; 264:8443). Isozymes of PKA are found
with two types of R subunits (RI and RII), and each type has
.alpha. and .beta. isoforms (Scott, Pharmacol. Ther. 1991; 50:123).
Thus, the four isoforms of PKA regulatory subunits are RI.alpha.,
RI.beta., RII.alpha. and RII.beta.. The R subunits have been
isolated only as stable dimers and the dimerization domain has been
shown to consist of the first 44 amino-terminal residues of
RII.alpha. or RII.beta. (Newlon et al., Nat. Struct. Biol. 1999;
6:222). As discussed below, similar portions of the amino acid
sequences of other regulatory subunits are involved in dimerization
and docking, each located at or near the N-terminal end of the
regulatory subunit. Binding of cAMP to the R subunits leads to the
release of active catalytic subunits for a broad spectrum of
serine/threonine kinase activities, which are oriented toward
selected substrates through the compartmentalization of PKA via its
docking with AKAPs (Scott et al., J. Biol. Chem. 1990; 265;
21561)
[0117] Since the first AKAP, microtubule-associated protein-2, was
characterized in 1984 (Lohmann et al., Proc. Natl. Acad. Sci USA.
1984; 81:6723), more than 50 AKAPs that localize to various
sub-cellular sites, including plasma membrane, actin cytoskeleton,
nucleus, mitochondria, and endoplasmic reticulum, have been
identified with diverse structures in species ranging from yeast to
humans (Wong and Scott, Nat. Rev. Mol. Cell Biol. 2004; 5:959). The
AD of AKAPs for PKA is an amphipathic helix of 14-18 residues (Carr
et al., J. Biol. Chem. 1991; 266:14188). The amino acid sequences
of the AD are quite varied among individual AKAPs, with the binding
affinities reported for RII dimers ranging from 2 to 90 nM (Alto et
al., Proc. Natl. Acad. Sci. USA. 2003; 100:4445). AKAPs will only
bind to dimeric R subunits. For human RII.alpha., the AD binds to a
hydrophobic surface formed by the 23 amino-terminal residues
(Colledge and Scott, Trends Cell Biol. 1999; 6:216). Thus, the
dimerization domain and AKAP binding domain of human RII.alpha. are
both located within the same N-terminal 44 amino acid sequence
(Newlon et al., Nat. Struct. Biol. 1999; 6:222; Newlon et al., EMBO
J. 2001; 20:1651), which is termed the DDD herein.
[0118] We have developed a platform technology to utilize the DDD
of human PKA regulatory subunits and the AD of AKAP as an excellent
pair of linker modules for docking any two entities, referred to
hereafter as A and B, into a noncovalent complex, which could be
further locked into a DNL.RTM. complex through the introduction of
cysteine residues into both the DDD and AD at strategic positions
to facilitate the formation of disulfide bonds. The general
methodology of the approach is as follows. Entity A is constructed
by linking a DDD sequence to a precursor of A, resulting in a first
component hereafter referred to as a. Because the DDD sequence
would effect the spontaneous formation of a dimer, A would thus be
composed of a.sub.2. Entity B is constructed by linking an AD
sequence to a precursor of B, resulting in a second component
hereafter referred to as b. The dimeric motif of DDD contained in
a.sub.2 will create a docking site for binding to the AD sequence
contained in b, thus facilitating a ready association of a.sub.2
and b to form a binary, trimeric complex composed of a.sub.2b. This
binding event is made irreversible with a subsequent reaction to
covalently secure the two entities via disulfide bridges, which
occurs very efficiently based on the principle of effective local
concentration because the initial binding interactions should bring
the reactive thiol groups placed onto both the DDD and AD into
proximity (Chmura et al., Proc. Natl. Acad. Sci. USA. 2001;
98:8480) to ligate site-specifically. Using various combinations of
linkers, adaptor modules and precursors, a wide variety of DNL.RTM.
constructs of different stoichiometry may be produced and used
(see, e.g., U.S. Pat. Nos. 7,550,143; 7,521,056; 7,534,866;
7,527,787 and 7,666,400.)
[0119] By attaching the DDD and AD away from the functional groups
of the two precursors, such site-specific ligations are also
expected to preserve the original activities of the two precursors.
This approach is modular in nature and potentially can be applied
to link, site-specifically and covalently, a wide range of
substances, including peptides, proteins, antibodies, antibody
fragments, and other effector moieties with a wide range of
activities. Utilizing the fusion protein method of constructing AD
and DDD conjugated effectors described in the Examples below,
virtually any protein or peptide may be incorporated into a
DNL.RTM. construct. However, the technique is not limiting and
other methods of conjugation may be utilized.
[0120] A variety of methods are known for making fusion proteins,
including nucleic acid synthesis, hybridization and/or
amplification to produce a synthetic double-stranded nucleic acid
encoding a fusion protein of interest. Such double-stranded nucleic
acids may be inserted into expression vectors for fusion protein
production by standard molecular biology techniques (see, e.g.
Sambrook et al., Molecular Cloning, A laboratory manual, 2.sup.nd
Ed, 1989). In such preferred embodiments, the AD and/or DDD moiety
may be attached to either the N-terminal or C-terminal end of an
effector protein or peptide. However, the skilled artisan will
realize that the site of attachment of an AD or DDD moiety to an
effector moiety may vary, depending on the chemical nature of the
effector moiety and the part(s) of the effector moiety involved in
its physiological activity. Site-specific attachment of a variety
of effector moieties may be performed using techniques known in the
art, such as the use of bivalent cross-linking reagents and/or
other chemical conjugation techniques.
[0121] Structure-Function Relationships in AD and DDD Moieties
[0122] For different types of DNL.RTM. constructs, different AD or
DDD sequences may be utilized. Exemplary DDD and AD sequences are
provided below.
TABLE-US-00003 DDD1 (SEQ ID NO: 9)
SHIQIPPGLTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA DDD2 (SEQ ID NO: 10)
CGHIQIPPGLTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA AD1 (SEQ ID NO: 11)
QIEYLAKQIVDNAIQQA AD2 (SEQ ID NO: 12) CGQIEYLAKQIVDNAIQQAGC
[0123] The skilled artisan will realize that DDD1 and DDD2 are
based on the DDD sequence of the human RII.alpha. isoform of
protein kinase A. However, in alternative embodiments, the DDD and
AD moieties may be based on the DDD sequence of the human RI.alpha.
form of protein kinase A and a corresponding AKAP sequence, as
exemplified in DDD3, DDD3C and AD3 below.
TABLE-US-00004 DDD3 (SEQ ID NO: 13)
SLRECELYVQKHNIQALLKDSIVQLCTARPERPMAFLREYFERLEKEEAK DDD3C (SEQ ID
NO: 14) MSCGGSLRECELYVQKHNIQALLKDSIVQLCTARPERPMAFLREYFERLE KEEAK
AD3 (SEQ ID NO: 15) CGFEELAWKIAKMIWSDVFQQGC
[0124] In other alternative embodiments, other sequence variants of
AD and/or DDD moieties may be utilized in construction of the
DNL.RTM. complexes. For example, there are only four variants of
human PKA DDD sequences, corresponding to the DDD moieties of PKA
RI.alpha., RII.alpha., RI.beta. and RII.beta.. The RII.alpha. DDD
sequence is the basis of DDD1 and DDD2 disclosed above. The four
human PKA DDD sequences are shown below. The DDD sequence
represents residues 1-44 of RII.alpha., 1-44 of RII.beta., 12-61 of
RI.alpha. and 13-66 of RI.beta.. (Note that the sequence of DDD1 is
modified slightly from the human PKA RII.alpha. DDD moiety.)
TABLE-US-00005 PKA RI.alpha. (SEQ ID NO: 16)
SLRECELYVQKHNIQALLKDVSIVQLCTARPERPMAFLREYFEKLEKEE AK PKA R1.beta.
(SEQ ID NO: 17) SLKGCELYVQLHGIQQVLKDCIVHLCISKPERPMKFLREHFEKLEKEENR
QILA PKA RII.alpha. (SEQ ID NO: 18)
SHIQIPPGLTELLQGYTVEVGQQPPDLVDFAVEYFTRLREARRQ PKA RII.beta. (SEQ ID
NO: 19) SIEIPAGLTELLQGFTVEVLRHQPADLLEFALQHFTRLQQENER
[0125] The structure-function relationships of the AD and DDD
domains have been the subject of investigation. (See, e.g.,
Burns-Hamuro et al., 2005, Protein Sci 14:2982-92; Carr et al.,
2001, J Biol Chem 276:17332-38; Alto et al., 2003, Proc Natl Acad
Sci USA 100:4445-50; Hundsrucker et al., 2006, Biochem J
396:297-306; Stokka et al., 2006, Biochem J 400:493-99; Gold et
al., 2006, Mol Cell 24:383-95; Kinderman et al., 2006, Mol Cell
24:397-408, the entire text of each of which is incorporated herein
by reference.)
[0126] Pre-Targeting
[0127] Bispecific or multispecific antibodies may be utilized in
pre-targeting techniques. Pre-targeting is a multistep process
originally developed to resolve the slow blood clearance of
directly targeting antibodies, which contributes to undesirable
toxicity to normal tissues such as bone marrow. With pre-targeting,
a radionuclide or other therapeutic agent is attached to a small
delivery molecule (targetable construct) that is cleared within
minutes from the blood. A pre-targeting bispecific or multispecific
antibody, which has binding sites for the targetable construct as
well as a target antigen, is administered first, free antibody is
allowed to clear from circulation and then the targetable construct
is administered.
[0128] Pre-targeting methods are disclosed, for example, in Goodwin
et al., U.S. Pat. No. 4,863,713; Goodwin et al., J. Nucl. Med.
29:226, 1988; Hnatowich et al., J. Nucl. Med. 28:1294, 1987; Oehr
et al., J. Nucl. Med. 29:728, 1988; Klibanov et al., J. Nucl. Med.
29:1951, 1988; Sinitsyn et al., J. Nucl. Med. 30:66, 1989;
Kalofonos et al., J. Nucl. Med. 31:1791, 1990; Schechter et al.,
Int. J. Cancer 48:167, 1991; Paganelli et al., Cancer Res. 51:5960,
1991; Paganelli et al., Nucl. Med. Commun. 12:211, 1991; U.S. Pat.
No. 5,256,395; Stickney et al., Cancer Res. 51:6650, 1991; Yuan et
al., Cancer Res. 51:3119, 1991; U.S. Pat. Nos. 6,077,499;
7,011,812; 7,300,644; 7,074,405; 6,962,702; 7,387,772; 7,052,872;
7,138,103; 6,090,381; 6,472,511; 6,962,702; and 6,962,702, each
incorporated herein by reference.
[0129] A pre-targeting method of treating or diagnosing a disease
or disorder in a subject may be provided by: (1) administering to
the subject a bispecific antibody or antibody fragment; (2)
optionally administering to the subject a clearing composition, and
allowing the composition to clear the antibody from circulation;
and (3) administering to the subject the targetable construct,
containing one or more chelated or chemically bound therapeutic or
diagnostic agents.
[0130] Targetable Constructs
[0131] In certain embodiments, targetable construct peptides
labeled with one or more therapeutic or diagnostic agents for use
in pre-targeting may be selected to bind to a bispecific antibody
with one or more binding sites for a targetable construct peptide
and one or more binding sites for a target antigen associated with
a disease or condition. Bispecific antibodies may be used in a
pretargeting technique wherein the antibody may be administered
first to a subject. Sufficient time may be allowed for the
bispecific antibody to bind to a target antigen and for unbound
antibody to clear from circulation. Then a targetable construct,
such as a labeled peptide, may be administered to the subject and
allowed to bind to the bispecific antibody and localize at the
diseased cell or tissue.
[0132] Such targetable constructs can be of diverse structure and
are selected not only for the availability of an antibody or
fragment that binds with high affinity to the targetable construct,
but also for rapid in vivo clearance when used within the
pre-targeting method and bispecific antibodies (bsAb) or
multispecific antibodies. Hydrophobic agents are best at eliciting
strong immune responses, whereas hydrophilic agents are preferred
for rapid in vivo clearance. Thus, a balance between hydrophobic
and hydrophilic character is established. This may be accomplished,
in part, by using hydrophilic chelating agents to offset the
inherent hydrophobicity of many organic moieties. Also, sub-units
of the targetable construct may be chosen which have opposite
solution properties, for example, peptides, which contain amino
acids, some of which are hydrophobic and some of which are
hydrophilic.
[0133] Peptides having as few as two amino acid residues,
preferably two to ten residues, may be used and may also be coupled
to other moieties, such as chelating agents. The linker should be a
low molecular weight conjugate, preferably having a molecular
weight of less than 50,000 daltons, and advantageously less than
about 20,000 daltons, 10,000 daltons or 5,000 daltons. More
usually, the targetable construct peptide will have four or more
residues, such as the peptide
DOTA-Phe-Lys(HSG)-Tyr-Lys(HSG)-NH.sub.2 (SEQ ID NO:20), wherein
DOTA is 1,4,7,10-tetraazacyclododecane1,4,7,10-tetraacetic acid and
HSG is the histamine succinyl glycyl group. Alternatively, DOTA may
be replaced by NOTA (1,4,7-triaza-cyclononane-1,4,7-triacetic
acid), TETA (p-bromoacetamido-benzyl-tetraethylaminetetraacetic
acid), NETA
([2-(4,7-biscarboxymethyl[1,4,7]triazacyclononan-1-yl-ethyl]-2-carbonylme-
thyl-amino]acetic acid) or other known chelating moieties.
Chelating moieties may be used, for example, to bind to a
therapeutic and or diagnostic radionuclide, paramagnetic ion or
contrast agent.
[0134] The targetable construct may also comprise unnatural amino
acids, e.g., D-amino acids, in the backbone structure to increase
the stability of the peptide in vivo. In alternative embodiments,
other backbone structures such as those constructed from
non-natural amino acids or peptoids may be used.
[0135] The peptides used as targetable constructs are conveniently
synthesized on an automated peptide synthesizer using a solid-phase
support and standard techniques of repetitive orthogonal
deprotection and coupling. Free amino groups in the peptide, that
are to be used later for conjugation of chelating moieties or other
agents, are advantageously blocked with standard protecting groups
such as a Boc group, while N-terminal residues may be acetylated to
increase serum stability. Such protecting groups are well known to
the skilled artisan. See Greene and Wuts Protective Groups in
Organic Synthesis, 1999 (John Wiley and Sons, N.Y.). When the
peptides are prepared for later use within the bispecific antibody
system, they are advantageously cleaved from the resins to generate
the corresponding C-terminal amides, in order to inhibit in vivo
carboxypeptidase activity.
[0136] Where pretargeting with bispecific antibodies is used, the
antibody will contain a first binding site for an antigen produced
by or associated with a target tissue and a second binding site for
a hapten on the targetable construct. Exemplary haptens include,
but are not limited to, HSG and In-DTPA. Antibodies raised to the
HSG hapten are known (e.g. 679 antibody) and can be easily
incorporated into the appropriate bispecific antibody (see, e.g.,
U.S. Pat. Nos. 6,962,702; 7,138,103 and 7,300,644, incorporated
herein by reference with respect to the Examples sections).
However, other haptens and antibodies that bind to them are known
in the art and may be used, such as In-DTPA and the 734 antibody
(e.g., U.S. Pat. No. 7,534,431, the Examples section incorporated
herein by reference).
[0137] Preparation of Immunoconjugates
[0138] In some embodiments, a therapeutic or diagnostic agent may
be covalently attached to an anti-CD22 antibody or antibody
fragment to form an immunoconjugate. Where the immunoconjugate is
to be administered in concentrated form by subcutaneous,
intramuscular or transdermal delivery, the skilled artisan will
realize that only non-cytotoxic agents may be conjugated to the
antibody. Where a second antibody or fragment thereof is
administered by a different route, such as intravenously, either
before, simultaneously with or after the subcutaneous,
intramuscular or transdermal delivery, then the type of diagnostic
or therapeutic agent that may be conjugated to the second antibody
or fragment thereof is not so limited, and may comprise any
diagnostic or therapeutic agent known in the art, including
cytotoxic agents.
[0139] In some embodiments, a diagnostic and/or therapeutic agent
may be attached to an antibody or fragment thereof via a carrier
moiety. Carrier moieties may be attached, for example to reduced SH
groups and/or to carbohydrate side chains. A carrier moiety can be
attached at the hinge region of a reduced antibody component via
disulfide bond formation. Alternatively, such agents can be
attached using a heterobifunctional cross-linker, such as
N-succinyl 3-(2-pyridyldithio)propionate (SPDP). Yu et al., Int. J.
Cancer 56: 244 (1994). General techniques for such conjugation are
well-known in the art. See, for example, Wong, CHEMISTRY OF PROTEIN
CONJUGATION AND CROSS-LINKING (CRC Press 1991); Upeslacis et al.,
"Modification of Antibodies by Chemical Methods," in MONOCLONAL
ANTIBODIES: PRINCIPLES AND APPLICATIONS, Birch et al. (eds.), pages
187-230 (Wiley-Liss, Inc. 1995); Price, "Production and
Characterization of Synthetic Peptide-Derived Antibodies," in
MONOCLONAL ANTIBODIES: PRODUCTION, ENGINEERING AND CLINICAL
APPLICATION, Ritter et al. (eds.), pages 60-84 (Cambridge
University Press 1995). Alternatively, the carrier moiety can be
conjugated via a carbohydrate moiety in the Fc region of the
antibody.
[0140] Methods for conjugating functional groups to antibodies via
an antibody carbohydrate moiety are well-known to those of skill in
the art. See, for example, Shih et al., Int. J. Cancer 41: 832
(1988); Shih et al., Int. J. Cancer 46: 1101 (1990); and Shih et
al., U.S. Pat. No. 5,057,313, the Examples section of which is
incorporated herein by reference. The general method involves
reacting an antibody having an oxidized carbohydrate portion with a
carrier polymer that has at least one free amine function. This
reaction results in an initial Schiff base (imine) linkage, which
can be stabilized by reduction to a secondary amine to form the
final conjugate.
[0141] The Fc region may be absent if the antibody component of the
immunoconjugate is an antibody fragment. However, it is possible to
introduce a carbohydrate moiety into the light chain variable
region of a full length antibody or antibody fragment. See, for
example, Leung et al., J. Immunol. 154: 5919 (1995); U.S. Pat. Nos.
5,443,953 and 6,254,868, the Examples section of which is
incorporated herein by reference. The engineered carbohydrate
moiety is used to attach the therapeutic or diagnostic agent.
[0142] An alternative method for attaching carrier moieties to a
targeting molecule involves use of click chemistry reactions. The
click chemistry approach was originally conceived as a method to
rapidly generate complex substances by joining small subunits
together in a modular fashion. (See, e.g., Kolb et al., 2004, Angew
Chem Int Ed 40:3004-31; Evans, 2007, Aust J Chem 60:384-95.)
Various forms of click chemistry reaction are known in the art,
such as the Huisgen 1,3-dipolar cycloaddition copper catalyzed
reaction (Tornoe et al., 2002, J Organic Chem 67:3057-64), which is
often referred to as the "click reaction." Other alternatives
include cycloaddition reactions such as the Diels-Alder,
nucleophilic substitution reactions (especially to small strained
rings like epoxy and aziridine compounds), carbonyl chemistry
formation of urea compounds and reactions involving carbon-carbon
double bonds, such as alkynes in thiol-yne reactions.
[0143] The azide alkyne Huisgen cycloaddition reaction uses a
copper catalyst in the presence of a reducing agent to catalyze the
reaction of a terminal alkyne group attached to a first molecule.
In the presence of a second molecule comprising an azide moiety,
the azide reacts with the activated alkyne to form a
1,4-disubstituted 1,2,3-triazole. The copper catalyzed reaction
occurs at room temperature and is sufficiently specific that
purification of the reaction product is often not required.
(Rostovstev et al., 2002, Angew Chem Int Ed 41:2596; Tornoe et al.,
2002, J Org Chem 67:3057.) The azide and alkyne functional groups
are largely inert towards biomolecules in aqueous medium, allowing
the reaction to occur in complex solutions. The triazole formed is
chemically stable and is not subject to enzymatic cleavage, making
the click chemistry product highly stable in biological systems.
Although the copper catalyst is toxic to living cells, the
copper-based click chemistry reaction may be used in vitro for
immunoconjugate formation.
[0144] A copper-free click reaction has been proposed for covalent
modification of biomolecules. (See, e.g., Agard et al., 2004, J Am
Chem Soc 126:15046-47.) The copper-free reaction uses ring strain
in place of the copper catalyst to promote a [3+2] azide-alkyne
cycloaddition reaction (Id.). For example, cyclooctyne is an
8-carbon ring structure comprising an internal alkyne bond. The
closed ring structure induces a substantial bond angle deformation
of the acetylene, which is highly reactive with azide groups to
form a triazole. Thus, cyclooctyne derivatives may be used for
copper-free click reactions (Id.).
[0145] Another type of copper-free click reaction was reported by
Ning et al. (2010, Angew Chem Int Ed 49:3065-68), involving
strain-promoted alkyne-nitrone cycloaddition. To address the slow
rate of the original cyclooctyne reaction, electron-withdrawing
groups are attached adjacent to the triple bond (Id.). Examples of
such substituted cyclooctynes include difluorinated cyclooctynes,
4-dibenzocyclooctynol and azacyclooctyne (Id.). An alternative
copper-free reaction involved strain-promoted alkyne-nitrone
cycloaddition to give N-alkylated isoxazolines (Id.). The reaction
was reported to have exceptionally fast reaction kinetics and was
used in a one-pot three-step protocol for site-specific
modification of peptides and proteins (Id.). Nitrones were prepared
by the condensation of appropriate aldehydes with
N-methylhydroxylamine and the cycloaddition reaction took place in
a mixture of acetonitrile and water (Id.). These and other known
click chemistry reactions may be used to attach carrier moieties to
antibodies in vitro.
[0146] Agard et al. (2004, J Am Chem Soc 126:15046-47) demonstrated
that a recombinant glycoprotein expressed in CHO cells in the
presence of peracetylated N-azidoacetylmannosamine resulted in the
bioincorporation of the corresponding N-azidoacetyl sialic acid in
the carbohydrates of the glycoprotein. The azido-derivatized
glycoprotein reacted specifically with a biotinylated cyclooctyne
to form a biotinylated glycoprotein, while control glycoprotein
without the azido moiety remained unlabeled (Id.). Laughlin et al.
(2008, Science 320:664-667) used a similar technique to
metabolically label cell-surface glycans in zebrafish embryos
incubated with peracetylated N-azidoacetylgalactosamine. The
azido-derivatized glycans reacted with difluorinated cyclooctyne
(DIFO) reagents to allow visualization of glycans in vivo.
[0147] The Diels-Alder reaction has also been used for in vivo
labeling of molecules. Rossin et al. (2010, Angew Chem Int Ed
49:3375-78) reported a 52% yield in vivo between a tumor-localized
anti-TAG72 (CC49) antibody carrying a trans-cyclooctene (TCO)
reactive moiety and an .sup.111In-labeled tetrazine DOTA
derivative. The TCO-labeled CC49 antibody was administered to mice
bearing colon cancer xenografts, followed 1 day later by injection
of .sup.111In-labeled tetrazine probe (Id.). The reaction of
radiolabeled probe with tumor localized antibody resulted in
pronounced radioactivity localization in the tumor, as demonstrated
by SPECT imaging of live mice three hours after injection of
radiolabeled probe, with a tumor-to-muscle ratio of 13:1 (Id.). The
results confirmed the in vivo chemical reaction of the TCO and
tetrazine-labeled molecules.
[0148] Antibody labeling techniques using biological incorporation
of labeling moieties are further disclosed in U.S. Pat. No.
6,953,675 (the Examples section of which is incorporated herein by
reference). Such "landscaped" antibodies were prepared to have
reactive ketone groups on glycosylated sites. The method involved
expressing cells transfected with an expression vector encoding an
antibody with one or more N-glycosylation sites in the CH1 or
V.kappa. domain in culture medium comprising a ketone derivative of
a saccharide or saccharide precursor. Ketone-derivatized
saccharides or precursors included N-levulinoyl mannosamine and
N-levulinoyl fucose. The landscaped antibodies were subsequently
reacted with agents comprising a ketone-reactive moiety, such as
hydrazide, hydrazine, hydroxylamino or thiosemicarbazide groups, to
form a labeled targeting molecule. Exemplary agents attached to the
landscaped antibodies included chelating agents like DTPA, large
drug molecules such as doxorubicin-dextran, and acyl-hydrazide
containing peptides. The landscaping technique is not limited to
producing antibodies comprising ketone moieties, but may be used
instead to introduce a click chemistry reactive group, such as a
nitrone, an azide or a cyclooctyne, onto an antibody or other
biological molecule.
[0149] Modifications of click chemistry reactions are suitable for
use in vitro or in vivo. Reactive targeting molecule may be formed
either by either chemical conjugation or by biological
incorporation. The targeting molecule, such as an antibody or
antibody fragment, may be activated with an azido moiety, a
substituted cyclooctyne or alkyne group, or a nitrone moiety. Where
the targeting molecule comprises an azido or nitrone group, the
corresponding targetable construct will comprise a substituted
cyclooctyne or alkyne group, and vice versa. Such activated
molecules may be made by metabolic incorporation in living cells,
as discussed above.
[0150] Alternatively, methods of chemical conjugation of such
moieties to biomolecules are well known in the art, and any such
known method may be utilized. General methods of immunoconjugate
formation are disclosed, for example, in U.S. Pat. Nos. 4,699,784;
4,824,659; 5,525,338; 5,677,427; 5,697,902; 5,716,595; 6,071,490;
6,187,284; 6,306,393; 6,548,275; 6,653,104; 6,962,702; 7,033,572;
7,147,856; and 7,259,240, the Examples section of each incorporated
herein by reference.
[0151] Therapeutic and Diagnostic Agents
[0152] In certain embodiments, the anti-CD22 antibodies or
fragments thereof may be used in combination with one or more
therapeutic and/or diagnostic agents. Therapeutic agents may be
selected from the group consisting of a radionuclide, an
immunomodulator, an anti-angiogenic agent, a cytokine, a chemokine,
a growth factor, a hormone, a drug, a prodrug, an enzyme, an
oligonucleotide, a pro-apoptotic agent, an interference RNA, a
photoactive therapeutic agent, a tyrosine kinase inhibitor, a
Bruton kinase inhibitor, a sphingosine inhibitor, a cytotoxic
agent, which may be a chemotherapeutic agent or a toxin, and a
combination thereof. The drugs of use may possess a pharmaceutical
property selected from the group consisting of antimitotic,
antikinase, alkylating, antimetabolite, antibiotic, alkaloid,
anti-angiogenic, pro-apoptotic agents, and combinations thereof
[0153] Exemplary drugs may include, but are not limited to,
5-fluorouracil, aplidin, azaribine, anastrozole, anthracyclines,
bendamustine, bleomycin, bortezomib, bryostatin-1, busulfan,
calicheamycin, camptothecin, carboplatin, 10-hydroxycamptothecin,
carmustine, celebrex, chlorambucil, cisplatin (CDDP), Cox-2
inhibitors, irinotecan (CPT-11), SN-38, carboplatin, cladribine,
camptothecans, cyclophosphamide, cytarabine, dacarbazine,
docetaxel, dactinomycin, daunorubicin, doxorubicin,
2-pyrrolinodoxorubicine (2P-DOX), a prodrug form of
2-pyrrolinodoxorubicine (P2PDox), cyano-morpholino doxorubicin,
doxorubicin glucuronide, epirubicin glucuronide, estramustine,
epipodophyllotoxin, estrogen receptor binding agents, etoposide
(VP16), etoposide glucuronide, etoposide phosphate, floxuridine
(FUdR), 3',5'-O-dioleoyl-FudR (FUdR-dO), fludarabine, flutamide,
farnesyl-protein transferase inhibitors, gemcitabine, hydroxyurea,
idarubicin, ifosfamide, L-asparaginase, lenolidamide, leucovorin,
lomustine, mechlorethamine, melphalan, mercaptopurine,
6-mercaptopurine, methotrexate, mitoxantrone, mithramycin,
mitomycin, mitotane, navelbine, nitrosourea, plicomycin,
procarbazine, paclitaxel, pentostatin, PSI-341, raloxifene,
semustine, streptozocin, tamoxifen, taxol, temazolomide (an aqueous
form of DTIC), transplatinum, thalidomide, thioguanine, thiotepa,
teniposide, topotecan, uracil mustard, vinorelbine, vinblastine,
vincristine and vinca alkaloids.
[0154] Toxins may include ricin, abrin, alpha toxin, saporin,
ribonuclease (RNase), e.g., onconase, DNase I, Staphylococcal
enterotoxin-A, pokeweed antiviral protein, gelonin, diphtheria
toxin, Pseudomonas exotoxin, and Pseudomonas endotoxin.
[0155] Immunomodulators may be selected from a cytokine, a stem
cell growth factor, a lymphotoxin, a hematopoietic factor, a colony
stimulating factor (CSF), an interferon (IFN), erythropoietin,
thrombopoietin and a combination thereof. Specifically useful are
lymphotoxins such as tumor necrosis factor (TNF), hematopoietic
factors, such as interleukin (IL), colony stimulating factor, such
as granulocyte-colony stimulating factor (G-CSF) or granulocyte
macrophage-colony stimulating factor (GM-CSF), interferon, such as
interferons-.alpha., -.beta., -.lamda. or -.gamma., and stem cell
growth factor, such as that designated "S1 factor". Included among
the cytokines are growth hormones such as human growth hormone,
N-methionyl human growth hormone, and bovine growth hormone;
parathyroid hormone; thyroxine; insulin; proinsulin; relaxin;
prorelaxin; glycoprotein hormones such as follicle stimulating
hormone (FSH), thyroid stimulating hormone (TSH), and luteinizing
hormone (LH); hepatic growth factor; prostaglandin, fibroblast
growth factor; prolactin; placental lactogen, OB protein; tumor
necrosis factor-.alpha. and -.beta.; mullerian-inhibiting
substance; mouse gonadotropin-associated peptide; inhibin; activin;
vascular endothelial growth factor; integrin; thrombopoietin (TPO);
nerve growth factors such as NGF-.beta.; platelet-growth factor;
transforming growth factors (TGFs) such as TGF-.alpha. and
TGF-.beta.; insulin-like growth factor-I and -II; erythropoietin
(EPO); osteoinductive factors; interferons such as
interferon-.alpha., -.beta., -.lamda. and -.gamma.; colony
stimulating factors (CSFs) such as macrophage-CSF (M-CSF);
interleukins (ILs) such as IL-1, IL-1.alpha., IL-2, IL-3, IL-4,
IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-11, IL-12; IL-13, IL-14,
IL-15, IL-16, IL-17, IL-18, IL-21, IL-23, IL-25, LIF, kit-ligand or
FLT-3, angiostatin, thrombospondin, endostatin, tumor necrosis
factor and lymphotoxin.
[0156] Chemokines of use include RANTES, MCAF, MIP1-alpha,
MIP1-Beta and IP-10.
[0157] Radioactive isotopes include, but are not limited
to--.sup.111In, .sup.177Lu, .sup.212Bi, .sup.213Bi, .sup.211At,
.sup.62Cu, .sup.67Cu, .sup.90Y, .sup.125I, .sup.131I, .sup.32P,
.sup.33P, .sup.47Sc, .sup.111Ag, .sup.67Ga, .sup.142Pr, .sup.153Sm,
.sup.161Tb, .sup.166Dy, .sup.166Ho, .sup.186Re, .sup.188Re,
.sup.189Re, .sup.212Pb, .sup.223Ra, .sup.225Ac, .sup.59Fe,
.sup.75Se, .sup.77As, .sup.89Sr, .sup.99Mo, .sup.105Rh, .sup.109Pd,
.sup.143Pr, .sup.149Pm, .sup.169Er, .sup.194Ir, .sup.198Au,
.sup.199Au, and .sup.211Pb. The therapeutic radionuclide preferably
has a decay-energy in the range of 20 to 6,000 keV, preferably in
the ranges 60 to 200 keV for an Auger emitter, 100-2,500 keV for a
beta emitter, and 4,000-6,000 keV for an alpha emitter. Maximum
decay energies of useful beta-particle-emitting nuclides are
preferably 20-5,000 keV, more preferably 100-4,000 keV, and most
preferably 500-2,500 keV. Also preferred are radionuclides that
substantially decay with Auger-emitting particles. For example,
Co-58, Ga-67, Br-80m, Tc-99m, Rh-103m, Pt-109, In-111, Sb-119,
1-125, Ho-161, Os-189m and Ir-192. Decay energies of useful
beta-particle-emitting nuclides are preferably <1,000 keV, more
preferably <100 keV, and most preferably <70 keV. Also
preferred are radionuclides that substantially decay with
generation of alpha-particles. Such radionuclides include, but are
not limited to: Dy-152, At-211, Bi-212, Ra-223, Rn-219, Po-215,
Bi-211, Ac-225, Fr-221, At-217, Bi-213, Fm-255 and Th-227. Decay
energies of useful alpha-particle-emitting radionuclides are
preferably 2,000-10,000 keV, more preferably 3,000-8,000 keV, and
most preferably 4,000-7,000 keV. Additional potential radioisotopes
of use include .sup.11C, .sup.13N, .sup.15O, .sup.75Br, .sup.198Au,
.sup.224Ac, .sup.126I, .sup.133I, .sup.77Br, .sup.113mIn,
.sup.95Ru, .sup.97Ru, .sup.103Ru, .sup.105Ru, .sup.107Hg,
.sup.203Hg, .sup.122mTe, .sup.125mTe, .sup.165Tm, .sup.167Tm,
.sup.168Tm, .sup.197Pt, .sup.109Pd, .sup.105Rh, .sup.142Pr,
.sup.143Pr, .sup.161Tb, .sup.166Ho, .sup.199Au, .sup.57Co,
.sup.58Co, .sup.51Cr, .sup.59Fe, .sup.75Se, .sup.201Tl, .sup.225Ac,
.sup.76Br, .sup.169Yb, and the like.
[0158] A variety of tyrosine kinase inhibitors are known in the art
and any such known therapeutic agent may be utilized. Exemplary
tyrosine kinase inhibitors include, but are not limited to
canertinib, dasatinib, erlotinib, gefitinib, imatinib, lapatinib,
leflunomide, nilotinib, pazopanib, semaxinib, sorafenib, sunitinib,
sutent and vatalanib. A specific class of tyrosine kinase inhibitor
is the Bruton tyrosine kinase inhibitor. Bruton tyrosine kinase
(Btk) has a well-defined role in B-cell development. Bruton kinase
inhibitors include, but are not limited to, PCI-32765 (ibrutinib),
PCI-45292, GDC-0834, LFM-A13 and RN486.
[0159] Therapeutic agents may include a photoactive agent or dye.
Fluorescent compositions, such as fluorochrome, and other
chromogens, or dyes, such as porphyrins sensitive to visible light,
have been used to detect and to treat lesions by directing the
suitable light to the lesion. In therapy, this has been termed
photoradiation, phototherapy, or photodynamic therapy. See Joni et
al. (eds.), PHOTODYNAMIC THERAPY OF TUMORS AND OTHER DISEASES
(Libreria Progetto 1985); van den Bergh, Chem. Britain (1986),
22:430. Moreover, monoclonal antibodies have been coupled with
photoactivated dyes for achieving phototherapy. See Mew et al., J.
Immunol. (1983), 130:1473; idem., Cancer Res. (1985), 45:4380;
Oseroff et al., Proc. Natl. Acad. Sci. USA (1986), 83:8744; idem.,
Photochem. Photobiol. (1987), 46:83; Hasan et al., Prog. Clin.
Biol. Res. (1989), 288:471; Tatsuta et al., Lasers Surg. Med.
(1989), 9:422; Pelegrin et al., Cancer (1991), 67:2529.
[0160] Corticosteroid hormones can increase the effectiveness of
other chemotherapy agents, and consequently, they are frequently
used in combination treatments. Prednisone and dexamethasone are
examples of corticosteroid hormones.
[0161] In certain embodiments, anti-angiogenic agents, such as
angiostatin, baculostatin, canstatin, maspin, anti-placenta growth
factor (PlGF) peptides and antibodies, anti-vascular growth factor
antibodies (such as anti-VEGF and anti-PlGF), anti-Flk-1
antibodies, anti-Flt-1 antibodies and peptides, anti-Kras
antibodies, anti-cMET antibodies, anti-MIF (macrophage
migration-inhibitory factor) antibodies, laminin peptides,
fibronectin peptides, plasminogen activator inhibitors, tissue
metalloproteinase inhibitors, interferons, interleukin-12, IP-10,
Gro-.beta., thrombospondin, 2-methoxyoestradiol, proliferin-related
protein, carboxiamidotriazole, CM101, Marimastat, pentosan
polysulphate, angiopoietin-2, interferon-alpha, interferon-lambda,
herbimycin A, PNU145156E, 16K prolactin fragment, Linomide,
thalidomide, pentoxifylline, genistein, TNP-470, endostatin,
paclitaxel, accutin, angiostatin, cidofovir, vincristine,
bleomycin, AGM-1470, platelet factor 4 or minocycline may be of
use.
[0162] The therapeutic agent may comprise an oligonucleotide, such
as a siRNA. The skilled artisan will realize that any siRNA or
interference RNA species may be attached to an antibody or fragment
thereof for delivery to a targeted tissue. Many siRNA species
against a wide variety of targets are known in the art, and any
such known siRNA may be utilized in the claimed methods and
compositions.
[0163] Known siRNA species of potential use include those specific
for IKK-gamma (U.S. Pat. No. 7,022,828); VEGF, Flt-1 and Flk-1/KDR
(U.S. Pat. No. 7,148,342); Bcl2 and EGFR (U.S. Pat. No. 7,541,453);
CDC20 (U.S. Pat. No. 7,550,572); transducin (beta)-like 3 (U.S.
Pat. No. 7,576,196); KRAS (U.S. Pat. No. 7,576,197); carbonic
anhydrase II (U.S. Pat. No. 7,579,457); complement component 3
(U.S. Pat. No. 7,582,746); interleukin-1 receptor-associated kinase
4 (IRAK4) (U.S. Pat. No. 7,592,443); survivin (U.S. Pat. No.
7,608,7070); superoxide dismutase 1 (U.S. Pat. No. 7,632,938); MET
proto-oncogene (U.S. Pat. No. 7,632,939); amyloid beta precursor
protein (APP) (U.S. Pat. No. 7,635,771); IGF-1R (U.S. Pat. No.
7,638,621); ICAM1 (U.S. Pat. No. 7,642,349); complement factor B
(U.S. Pat. No. 7,696,344); p53 (U.S. Pat. No. 7,781,575), and
apolipoprotein B (U.S. Pat. No. 7,795,421), the Examples section of
each referenced patent incorporated herein by reference.
[0164] Additional siRNA species are available from known commercial
sources, such as Sigma-Aldrich (St Louis, Mo.), Invitrogen
(Carlsbad, Calif.), Santa Cruz Biotechnology (Santa Cruz, Calif.),
Ambion (Austin, Tex.), Dharmacon (Thermo Scientific, Lafayette,
Colo.), Promega (Madison, Wis.), Minis Bio (Madison, Wis.) and
Qiagen (Valencia, Calif.), among many others. Other publicly
available sources of siRNA species include the siRNAdb database at
the Stockholm Bioinformatics Centre, the MIT/ICBP siRNA Database,
the RNAi Consortium shRNA Library at the Broad Institute, and the
Probe database at NCBI. For example, there are 30,852 siRNA species
in the NCBI Probe database. The skilled artisan will realize that
for any gene of interest, either a siRNA species has already been
designed, or one may readily be designed using publicly available
software tools. Any such siRNA species may be delivered using the
subject DNL.RTM. complexes.
[0165] Diagnostic agents are preferably selected from the group
consisting of a radionuclide, a radiological contrast agent, a
paramagnetic ion, a metal, a fluorescent label, a chemiluminescent
label, an ultrasound contrast agent and a photoactive agent. Such
diagnostic agents are well known and any such known diagnostic
agent may be used. Non-limiting examples of diagnostic agents may
include a radionuclide such as .sup.18F, .sup.52Fe, .sup.110In,
.sup.111In, .sup.177Lu, .sup.52Fe, .sup.62Cu, .sup.64Cu, .sup.67Cu,
.sup.67Ga, .sup.68Ga, .sup.86Y, .sup.90Y, .sup.89Zr, .sup.94mTc,
.sup.94Tc, .sup.99mTc, .sup.120I, .sup.123I, .sup.124I, .sup.125I,
.sup.131I, .sup.154-158Gd, .sup.32P, .sup.11C, .sup.13N, .sup.15O,
.sup.186Re, .sup.188Re, .sup.51Mn, .sup.52mMn, .sup.55Co,
.sup.72As, .sup.75Br, .sup.76Br, .sup.82mRb, .sup.83Sr, or other
gamma-, beta-, or positron-emitters.
[0166] Paramagnetic ions of use may include chromium (III),
manganese (II), iron (III), iron (II), cobalt (II), nickel (II),
copper (II), neodymium (III), samarium (III), ytterbium (III),
gadolinium (III), vanadium (II), terbium (III), dysprosium (III),
holmium (III) or erbium (III). Metal contrast agents may include
lanthanum (III), gold (III), lead (II) or bismuth (III).
[0167] Ultrasound contrast agents may comprise liposomes, such as
gas filled liposomes. Radiopaque diagnostic agents may be selected
from compounds, barium compounds, gallium compounds, and thallium
compounds. A wide variety of fluorescent labels are known in the
art, including but not limited to fluorescein isothiocyanate,
rhodamine, phycoerytherin, phycocyanin, allophycocyanin,
o-phthaldehyde and fluorescamine. Chemiluminescent labels of use
may include luminol, isoluminol, an aromatic acridinium ester, an
imidazole, an acridinium salt or an oxalate ester.
[0168] Methods of Administration
[0169] The subject antibodies and immunoglobulins in general may be
formulated to obtain compositions that include one or more
pharmaceutically suitable excipients, surfactants, polyols,
buffers, salts, amino acids, or additional ingredients, or some
combination of these. This can be accomplished by known methods to
prepare pharmaceutically useful dosages, whereby the active
ingredients (i.e., the labeled molecules) are combined in a mixture
with one or more pharmaceutically suitable excipients. Sterile
phosphate-buffered saline is one example of a pharmaceutically
suitable excipient. Other suitable excipients are well known to
those in the art. See, e.g., Ansel et al., PHARMACEUTICAL DOSAGE
FORMS AND DRUG DELIVERY SYSTEMS, 5th Edition (Lea & Febiger
1990), and Gennaro (ed.), REMINGTON'S PHARMACEUTICAL SCIENCES, 18th
Edition (Mack Publishing Company 1990), and revised editions
thereof
[0170] The preferred route for administration of the compositions
described herein is parenteral injection, more preferably by
subcutaneous, intramuscular or transdermal delivery. Other forms of
parenteral administration include intravenous, intraarterial,
intralymphatic, intrathecal, intraocular, intracerebral, or
intracavitary injection. In parenteral administration, the
compositions will be formulated in a unit dosage injectable form
such as a solution, suspension or emulsion, in association with a
pharmaceutically acceptable excipient. Such excipients are
inherently nontoxic and nontherapeutic. Examples of such excipients
are saline, Ringer's solution, dextrose solution and Hanks'
solution. Nonaqueous excipients such as fixed oils and ethyl oleate
may also be used. An alternative excipient is 5% dextrose in
saline. The excipient may contain minor amounts of additives such
as substances that enhance isotonicity and chemical stability,
including buffers and preservatives.
[0171] Formulated compositions comprising antibodies can be used
for subcutaneous, intramuscular or transdermal administration.
Compositions can be presented in unit dosage form, e.g., in
ampoules or in multi-dose containers, with an added preservative.
Compositions can also take such forms as suspensions, solutions or
emulsions in oily or aqueous vehicles, and can contain formulatory
agents such as suspending, stabilizing and/or dispersing agents.
Alternatively, the compositions can be in powder form for
constitution with a suitable vehicle, e.g., sterile pyrogen-free
water, before use.
[0172] The compositions may be administered in solution. The
formulation thereof should be in a solution having a suitable
pharmaceutically acceptable buffer such as phosphate, TRIS
(hydroxymethyl) aminomethane-HCl or citrate and the like. Buffer
concentrations should be in the range of 1 to 100 mM. The
formulated solution may also contain a salt, such as sodium
chloride or potassium chloride in a concentration of 50 to 150 mM.
An effective amount of a stabilizing agent such as mannitol,
trehalose, sorbitol, glycerol, albumin, a globulin, a detergent, a
gelatin, a protamine or a salt of protamine may also be
included.
[0173] The dosage of an administered antibody for humans will vary
depending upon such factors as the patient's age, weight, height,
sex, general medical condition and previous medical history.
Typically, it is desirable to provide the recipient with a dosage
of antibody that is in the range of from about 1 mg to 600 mg as a
single infusion or single or multiple injections, although a lower
or higher dosage also may be administered. Typically, it is
desirable to provide the recipient with a dosage that is in the
range of from about 50 mg per square meter (m.sup.2) of body
surface area or 70 to 85 mg of the antibody for the typical adult,
although a lower or higher dosage also may be administered.
Examples of dosages of antibodies that may be administered to a
human subject are 1 to 1,000 mg, more preferably 1 to 70 mg, most
preferably 1 to 20 mg, although higher or lower doses may be used.
Dosages may be repeated as needed, for example, once per week for
4-10 weeks, preferably once per week for 8 weeks, and more
preferably, once per week for 4 weeks. It may also be given less
frequently, such as every other week for several months, or more
frequently, such as twice weekly or by continuous infusion.
[0174] More recently, subcutaneous administration of veltuzumab has
been given to NHL patients in 4 doses of 80, 160 or 320 mg,
repeated every two weeks (Negrea et al., 2011, Haematologica
96:567-73). Only occasional, mild to moderate and transient
injection reactions were observed, with no other safety issues
(Id.). The objective response rate (CR+CRu+PR) was 47%, with a
CR/CRu (complete response) rate of 24% (Id.). Interestingly, the 80
mg dosage group showed the highest percentage of objective response
(2/3, 67%), with one of three patients showing a complete response
(Id.). Four out of eight objective responses continued for 60 weeks
(Id.). All serum samples evaluated for HAHA were negative (Id.).
Although the low sample population reported in this study precludes
any definitive conclusions on optimal dosing, it is apparent that
therapeutic response was observed at the lowest dosage tested (80
mg).
[0175] In certain alternative embodiments, the antibody may be
administered by transdermal delivery. Different methods of
transdermal delivery are known in the art, such as by transdermal
patches or by microneedle devices, and any such known method may be
utilized. In an exemplary embodiment, transdermal delivery may
utilize a delivery device such as the 3M hollow Microstructured
Transdermal System (hMTS) for antibody based therapeutics. The hMTS
device comprises a 1 cm.sup.2 microneedle array consisting of 18
hollow microneedles that are 950 microns in length, which penetrate
approximately 600-700 microns into the dermal layer of the skin
where there is a high density of lymphatic channels. A
spring-loaded device forces the antibody composition from a fluid
reservoir through the microneedles for delivery to the subject.
Only transient erythema and edema at the injection site are
observed (Burton et al., 2011, Pharm Res 28:31-40). The hMTS device
is not perceived as a needle injector, resulting in improved
patient compliance.
[0176] In preferred embodiments where the antibody is administered
subcutaneously, intramuscularly or transdermally in a concentrated
formulation, the volume of administration is preferably limited to
3 ml or less, more preferably 2 ml or less, more preferably 1 ml or
less. The use of concentrated antibody formulations allowing low
volume subcutaneous, intramuscular or transdermal administration is
preferred to the use of more dilute antibody formulations that
require specialized devices and ingredients (e.g., hyaluronidase)
for subcutaneous administration of larger volumes of fluid, such as
10 ml or more. The subcutaneous, intramuscular or transdermal
delivery may be administered as a single administration to one skin
site or alternatively may be repeated one or more times, or even
given to more than one skin site in one therapeutic dosing session.
However, the more concentrated the formulation, the lower the
volume injected and the fewer injections will be needed for each
therapeutic dosing.
[0177] Methods of Use
[0178] In preferred embodiments, the anti-CD22 antibodies are of
use for therapy of cancer. Examples of cancers include, but are not
limited to, carcinoma, lymphoma, blastoma, glioma, melanoma,
sarcoma, and leukemia or lymphoid malignancies. More particular
examples of such cancers are noted below and include: squamous cell
cancer (e.g. epithelial squamous cell cancer), lung cancer
including small-cell lung cancer, non-small cell lung cancer,
adenocarcinoma of the lung and squamous carcinoma of the lung,
cancer of the peritoneum, hepatocellular cancer, gastric or stomach
cancer including gastrointestinal cancer, pancreatic cancer,
glioblastoma, neuroblastoma, cervical cancer, ovarian cancer, liver
cancer, bladder cancer, hepatoma, breast cancer, colon cancer,
rectal cancer, endometrial cancer or uterine carcinoma, salivary
gland carcinoma, kidney or renal cancer, prostate cancer, vulval
cancer, thyroid cancer, anal carcinoma, penile carcinoma, as well
as head and neck cancer. The term "cancer" includes primary
malignant cells or tumors (e.g., those whose cells have not
migrated to sites in the subject's body other than the site of the
original malignancy or tumor) and secondary malignant cells or
tumors (e.g., those arising from metastasis, the migration of
malignant cells or tumor cells to secondary sites that are
different from the site of the original tumor).
[0179] Other examples of cancers or malignancies include, but are
not limited to: acute childhood lymphoblastic leukemia, acute
lymphoblastic leukemia, acute lymphocytic leukemia, acute myeloid
leukemia, adrenocortical carcinoma, adult (primary) hepatocellular
cancer, adult (primary) liver cancer, adult acute lymphocytic
leukemia, adult acute myeloid leukemia, adult Hodgkin's disease,
adult Hodgkin's lymphoma, adult lymphocytic leukemia, adult
non-Hodgkin's lymphoma, adult primary liver cancer, adult soft
tissue sarcoma, AIDS-related lymphoma, AIDS-related malignancies,
anal cancer, astrocytoma, bile duct cancer, bladder cancer, bone
cancer, brain stem glioma, brain tumors, breast cancer, cancer of
the renal pelvis and ureter, central nervous system (primary)
lymphoma, central nervous system lymphoma, cerebellar astrocytoma,
cerebral astrocytoma, cervical cancer, childhood (primary)
hepatocellular cancer, childhood (primary) liver cancer, childhood
acute lymphoblastic leukemia, childhood acute myeloid leukemia,
childhood brain stem glioma, childhood cerebellar astrocytoma,
childhood cerebral astrocytoma, childhood extracranial germ cell
tumors, childhood Hodgkin's disease, childhood Hodgkin's lymphoma,
childhood hypothalamic and visual pathway glioma, childhood
lymphoblastic leukemia, childhood medulloblastoma, childhood
non-Hodgkin's lymphoma, childhood pineal and supratentorial
primitive neuroectodermal tumors, childhood primary liver cancer,
childhood rhabdomyosarcoma, childhood soft tissue sarcoma,
childhood visual pathway and hypothalamic glioma, chronic
lymphocytic leukemia, chronic myelogenous leukemia, colon cancer,
cutaneous T-cell lymphoma, endocrine pancreas islet cell carcinoma,
endometrial cancer, ependymoma, epithelial cancer, esophageal
cancer, Ewing's sarcoma and related tumors, exocrine pancreatic
cancer, extracranial germ cell tumor, extragonadal germ cell tumor,
extrahepatic bile duct cancer, eye cancer, female breast cancer,
Gaucher's disease, gallbladder cancer, gastric cancer,
gastrointestinal carcinoid tumor, gastrointestinal tumors, germ
cell tumors, gestational trophoblastic tumor, hairy cell leukemia,
head and neck cancer, hepatocellular cancer, Hodgkin's disease,
Hodgkin's lymphoma, hypergammaglobulinemia, hypopharyngeal cancer,
intestinal cancers, intraocular melanoma, islet cell carcinoma,
islet cell pancreatic cancer, Kaposi's sarcoma, kidney cancer,
laryngeal cancer, lip and oral cavity cancer, liver cancer, lung
cancer, lymphoproliferative disorders, macroglobulinemia, male
breast cancer, malignant mesothelioma, malignant thymoma,
medulloblastoma, melanoma, mesothelioma, metastatic occult primary
squamous neck cancer, metastatic primary squamous neck cancer,
metastatic squamous neck cancer, multiple myeloma, multiple
myeloma/plasma cell neoplasm, myelodysplastic syndrome, myelogenous
leukemia, myeloid leukemia, myeloproliferative disorders, nasal
cavity and paranasal sinus cancer, nasopharyngeal cancer,
neuroblastoma, non-Hodgkin's lymphoma during pregnancy, nonmelanoma
skin cancer, non-small cell lung cancer, occult primary metastatic
squamous neck cancer, oropharyngeal cancer, osteo-/malignant
fibrous sarcoma, osteosarcoma/malignant fibrous hi stiocytoma,
osteosarcoma/malignant fibrous histiocytoma of bone, ovarian
epithelial cancer, ovarian germ cell tumor, ovarian low malignant
potential tumor, pancreatic cancer, paraproteinemias, purpura,
parathyroid cancer, penile cancer, pheochromocytoma, pituitary
tumor, plasma cell neoplasm/multiple myeloma, primary central
nervous system lymphoma, primary liver cancer, prostate cancer,
rectal cancer, renal cell cancer, renal pelvis and ureter cancer,
retinoblastoma, rhabdomyosarcoma, salivary gland cancer,
sarcoidosis sarcomas, Sezary syndrome, skin cancer, small cell lung
cancer, small intestine cancer, soft tissue sarcoma, squamous neck
cancer, stomach cancer, supratentorial primitive neuroectodermal
and pineal tumors, T-cell lymphoma, testicular cancer, thymoma,
thyroid cancer, transitional cell cancer of the renal pelvis and
ureter, transitional renal pelvis and ureter cancer, trophoblastic
tumors, ureter and renal pelvis cell cancer, urethral cancer,
uterine cancer, uterine sarcoma, vaginal cancer, visual pathway and
hypothalamic glioma, vulvar cancer, Waldenstrom's
macroglobulinemia, Wilms' tumor, and any other hyperproliferative
disease, besides neoplasia, located in an organ system listed
above.
[0180] The methods and compositions described and claimed herein
may be used to detect or treat malignant or premalignant
conditions. Such uses are indicated in conditions known or
suspected of preceding progression to neoplasia or cancer, in
particular, where non-neoplastic cell growth consisting of
hyperplasia, metaplasia, or most particularly, dysplasia has
occurred (for review of such abnormal growth conditions, see
Robbins and Angell, Basic Pathology, 2d Ed., W. B. Saunders Co.,
Philadelphia, pp. 68-79 (1976)).
[0181] Dysplasia is frequently a forerunner of cancer, and is found
mainly in the epithelia. It is the most disorderly form of
non-neoplastic cell growth, involving a loss in individual cell
uniformity and in the architectural orientation of cells. Dysplasia
characteristically occurs where there exists chronic irritation or
inflammation. Dysplastic disorders which can be detected include,
but are not limited to, anhidrotic ectodermal dysplasia,
anterofacial dysplasia, asphyxiating thoracic dysplasia,
atriodigital dysplasia, bronchopulmonary dysplasia, cerebral
dysplasia, cervical dysplasia, chondroectodermal dysplasia,
cleidocranial dysplasia, congenital ectodermal dysplasia,
craniodiaphysial dysplasia, craniocarpotarsal dysplasia,
craniometaphysial dysplasia, dentin dysplasia, diaphysial
dysplasia, ectodermal dysplasia, enamel dysplasia,
encephalo-ophthalmic dysplasia, dysplasia epiphysialis hemimelia,
dysplasia epiphysialis multiplex, dysplasia epiphysialis punctata,
epithelial dysplasia, faciodigitogenital dysplasia, familial
fibrous dysplasia of jaws, familial white folded dysplasia,
fibromuscular dysplasia, fibrous dysplasia of bone, florid osseous
dysplasia, hereditary renal-retinal dysplasia, hidrotic ectodermal
dysplasia, hypohidrotic ectodermal dysplasia, lymphopenic thymic
dysplasia, mammary dysplasia, mandibulofacial dysplasia,
metaphysial dysplasia, Mondini dysplasia, monostotic fibrous
dysplasia, mucoepithelial dysplasia, multiple epiphysial dysplasia,
oculoauriculovertebral dysplasia, oculodentodigital dysplasia,
oculovertebral dysplasia, odontogenic dysplasia,
opthalmomandibulomelic dysplasia, periapical cemental dysplasia,
polyostotic fibrous dysplasia, pseudoachondroplastic
spondyloepiphysial dysplasia, retinal dysplasia, septo-optic
dysplasia, spondyloepiphysial dysplasia, and ventriculoradial
dysplasia.
[0182] Additional pre-neoplastic disorders which can be detected
and/or treated include, but are not limited to, benign
dysproliferative disorders (e.g., benign tumors, fibrocystic
conditions, tissue hypertrophy, intestinal polyps, colon polyps,
and esophageal dysplasia), leukoplakia, keratoses, Bowen's disease,
Farmer's Skin, solar cheilitis, and solar keratosis.
[0183] Additional hyperproliferative diseases, disorders, and/or
conditions include, but are not limited to, progression, and/or
metastases of malignancies and related disorders such as leukemia
(including acute leukemias (e.g., acute lymphocytic leukemia, acute
myelocytic leukemia (including myeloblastic, promyelocytic,
myelomonocytic, monocytic, and erythroleukemia) and chronic
leukemias (e.g., chronic myelocytic (granulocytic) leukemia and
chronic lymphocytic leukemia)), polycythemia vera, lymphomas (e.g.,
Hodgkin's disease and non-Hodgkin's disease), multiple myeloma,
Waldenstrom's macroglobulinemia, heavy chain disease, and solid
tumors including, but not limited to, sarcomas and carcinomas such
as fibrosarcoma, myxosarcoma, liposarcoma, chondrosarcoma,
osteogenic sarcoma, chordoma, angiosarcoma, endotheliosarcoma,
lymphangiosarcoma, lymphangioendotheliosarcoma, synovioma,
mesothelioma, Ewing's tumor, leiomyosarcoma, rhabdomyosarcoma,
colon carcinoma, pancreatic cancer, breast cancer, ovarian cancer,
prostate cancer, squamous cell carcinoma, basal cell carcinoma,
adenocarcinoma, sweat gland carcinoma, sebaceous gland carcinoma,
papillary carcinoma, papillary adenocarcinomas, cystadenocarcinoma,
medullary carcinoma, bronchogenic carcinoma, renal cell carcinoma,
hepatoma, bile duct carcinoma, choriocarcinoma, seminoma, embryonal
carcinoma, Wilm's tumor, cervical cancer, testicular tumor, lung
carcinoma, small cell lung carcinoma, bladder carcinoma, epithelial
carcinoma, glioma, astrocytoma, medulloblastoma, craniopharyngioma,
ependymoma, pinealoma, emangioblastoma, acoustic neuroma,
oligodendroglioma, menangioma, melanoma, neuroblastoma, and
retinoblastoma.
[0184] The exemplary conditions listed above that may be treated
are not limiting. The skilled artisan will be aware that antibodies
or antibody fragments are known for a wide variety of conditions,
such as autoimmune disease, graft-versus-host-disease, organ
transplant rejection, cardiovascular disease, neurodegenerative
disease, metabolic disease, cancer, infectious disease and
hyperproliferative disease.
[0185] Exemplary autoimmune diseases include acute idiopathic
thrombocytopenic purpura, chronic immune thrombocytopenia,
dermatomyositis, Sydenham's chorea, myasthenia gravis, systemic
lupus erythematosus, lupus nephritis, rheumatic fever,
polyglandular syndromes, bullous pemphigoid, pemphigus vulgaris,
juvenile diabetes mellitus, Henoch-Schonlein purpura,
post-streptococcal nephritis, erythema nodosum, Takayasu's
arteritis, ANCA-associated vasculitides, Addison's disease,
rheumatoid arthritis, multiple sclerosis, sarcoidosis, ulcerative
colitis, erythema multiforme, IgA nephropathy, polyarteritis
nodosa, ankylosing spondylitis, Goodpasture's syndrome,
thromboangitis obliterans, Sjogren's syndrome, primary biliary
cirrhosis, Hashimoto's thyroiditis, thyrotoxicosis, scleroderma,
chronic active hepatitis, polymyositis/dermatomyositis,
polychondritis, pemphigus vulgaris, Wegener's granulomatosis,
membranous nephropathy, amyotrophic lateral sclerosis, tabes
dorsalis, giant cell arteritis/polymyalgia, pernicious anemia,
rapidly progressive glomerulonephritis, psoriasis and fibrosing
alveolitis.
[0186] Kits
[0187] Various embodiments may concern kits containing components
suitable for treating diseased tissue in a patient. Exemplary kits
may contain at least one concentrated antibody or fragment thereof
as described herein. A device capable of delivering the kit
components by injection, for example, a syringe for subcutaneous
injection, may be included. Where transdermal administration is
used, a delivery device such as hollow microneedle delivery device
may be included in the kit. Exemplary transdermal delivery devices
are known in the art, such as 3M's hollow Microstructured
Transdermal System (hMTS), and any such known device may be
used.
[0188] The kit components may be packaged together or separated
into two or more containers. In some embodiments, the containers
may be vials that contain sterile, lyophilized formulations of a
composition that are suitable for reconstitution. A kit may also
contain one or more buffers suitable for reconstitution and/or
dilution of other reagents. Alternatively, the concentrated
antibody may be delivered and stored as a liquid formulation. Other
containers that may be used include, but are not limited to, a
pouch, tray, box, tube, or the like. Kit components may be packaged
and maintained sterilely within the containers. Another component
that can be included is instructions to a person using a kit for
its use.
Examples
Example 1. Crosslinking of CD22 by Anti-CD22 Antibody Triggers BCR
Signaling and Caspase-Dependent Apoptosis in Hematopoietic Cancer
Cells
[0189] The anti-CD22 antibody epratuzumab has demonstrated
therapeutic activity in patients with non-Hodgkin lymphoma, acute
lymphoblastic leukemia, systemic lupus erythematosus, and Sjogren's
syndrome, but its mechanism of affecting normal and malignant B
cells remains incompletely understood. We reported previously that
epratuzumab displayed in vitro cytotoxicity to CD22-expressing
Burkitt lymphoma cell lines (Daudi and Ramos) only when immobilized
on plates or combined with a crosslinking antibody plus a
suboptimal amount of anti-IgM (1 .mu.g/mL). Herein, we show that,
in the absence of additional anti-IgM ligation, extensive
crosslinking of CD22 by plate-immobilized epratuzumab induced
intracellular changes in Daudi cells similar to ligating B-cell
antigen receptor (BCR) with a sufficiently high amount of anti-IgM
(10 .mu.g/mL).
[0190] Specifically, either treatment led to phosphorylation of
CD22, CD79a and CD79b, along with their translocation to lipid
rafts, both of which were essential for effecting caspase-dependent
apoptosis. Moreover, such immobilization induced stabilization of
F-actin, phosphorylation of Lyn, ERKs and JNKs, generation of
reactive oxygen species (ROS), decrease in mitochondria membrane
potential (.DELTA..psi..sub.m), upregulation of pro-apoptotic Bax,
and downregulation of anti-apoptotic Bcl-xl and Mcl-1. The
physiological relevance of immobilized epratuzumab was implicated
by noting that several of its in vitro effects, including
apoptosis, drop in .DELTA..psi..sub.m, and generation of ROS, could
be observed with soluble epratuzumab in Daudi cells co-cultivated
with human umbilical vein endothelial cells. These results suggest
that the in vivo mechanism of non-ligand-blocking epratuzumab may,
in part, involve the unmasking of CD22 to facilitate the
trans-interaction of B cells with vascular endothelium.
[0191] In the studies disclosed below, we further explored the
molecular events associated with the cytotoxicity of epratuzumab in
vitro, examining epratuzumab presented in soluble or immobilized
form in various combinations, as summarized in Table 2. We showed
in Daudi and D1-1 cells that epratuzumab by non-covalent adsorption
on microtiter plates (the Dried-I format, Table 2) induces
phosphorylation of CD22, CD79a and CD79b, as well as their
translocation to lipid rafts, which are instrumental for cell death
via caspase-dependent apoptosis. Such plate-immobilized epratuzumab
likewise induced substantial apoptosis and growth inhibition in
Ramos cells. Treatment of D1-1 cells with the Dried-I format also
revealed multiple intracellular changes that included sustained
phosphorylation of ERK and JNK MAP kinases, decrease in
.DELTA..psi..sub.m, generation of ROS, activation of caspases, as
well as upregulation and downregulation of pro- and anti-apoptotic
proteins, respectively. Interestingly, several of the in vitro
effects observed with the Dried-I format, including apoptosis, drop
in .DELTA..psi..sub.m, and generation of ROS, could be observed
with the Dried-II format (Table 2) comprising co-cultivation of
Daudi cells over a monolayer of human umbilical vein endothelial
cells (HUV-EC) in the presence of soluble epratuzumab (20
.mu.g/mL). These findings indicate a physiological relevance of
immobilized epratuzumab, and suggest that the in vivo mechanism of
non-ligand-blocking epratuzumab may, in part, involve the unmasking
of CD22 to facilitate the trans-interaction of B cells with
vascular endothelium.
[0192] Abbreviations used herein include: Anti-IgM, F(ab').sub.2
fragment of affinity-purified goat anti-human IgM, Fc.sub.5.mu.
fragment; BCR, B-cell antigen receptor; BSA, bovine serum albumin;
CM-H.sub.2DCF-DA, 2',7'-dichlorodihydrofluorescein diacetate;
.DELTA..psi..sub.m, mitochondria membrane potential; DNP,
2,4-dinitrophenyl; EC, endothelial cells; ERKs, extracellular
signal-regulated kinases; FBS, fetal bovine serum; FITC-DNase I,
fluorescein isothiocyanate-conjugated DNase I; 488-annexin V, Alexa
Fluor 488-conjugated annexin V; GAH, F(ab').sub.2 fragment of
affinity-purified goat anti-human IgG Fc.gamma. fragment-specific;
HUV-EC, human umbilical vein endothelial cells; ITIM,
immunoreceptor tyrosine-based inhibition motif; JNKs, c-Jun
N-terminal kinases; JP, jasplakinolide; LatB, latrunculin B; Lyn,
Lck/Yes novel tyrosine kinase; MAP kinases, mitogen-activated
protein kinases; mIgM, membrane IgM; MTS,
(3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl-
)-2H-tetrazolium; PARP, poly ADP ribose polymerase; PBS,
phosphate-buffered saline; PLC.gamma.2, phospholipase C, isotype
gamma 2; Rhodamine-anti-IgG, rhodamine-conjugated F(ab').sub.2
fragment of affinity-purified goat anti-human IgG, F(ab').sub.2
fragment-specific; ROS, reactive oxygen species; 7-AAD,
7-aminoactinomycin D; Syk, spleen tyrosine kinase; TMRE,
tetramethylrhodamine, ethyl ester
[0193] Materials and Methods
[0194] Cell Lines, Antibodies, and Reagents.
[0195] All cell lines, except D1-1 (a subclone of Daudi with a
higher expression of BCR than D-1-7), were obtained from the
American Type Culture Collection (Manassas, Va.) and have been
authenticated by Promega (Madison, Wis.) using Short Tandem Repeat
(STR) analysis. Phospho-specific antibodies for ERK, JNK,
PLC.gamma.2, and Lyn were obtained from Cell Signaling (Danvers,
Mass.), as were antibodies specific for .beta.-actin, Bcl-xL,
Mcl-1, Caspase-3, Caspase-9, and PARP. The sources of other
antibodies were as follows: Santa Cruz Biotech (Santa Cruz, Calif.)
for CD22, CD79a, CD79b, Bcl-2, and Bax; Millipore (Billerica,
Mass.) for anti-tyrosine (4G10); and Jackson ImmunoResearch (West
Grove, Pa.) for F(ab').sub.2 fragment of affinity purified goat
anti-human IgM, Fc.sub.5.mu. fragment-specific (anti-IgM),
F(ab').sub.2 fragment of affinity purified goat anti-human IgG
Fc.gamma. fragment-specific (GAH), and rhodamine-conjugated
F(ab').sub.2 fragment of affinity-purified goat anti-human IgG,
F(ab').sub.2 fragment-specific (rhodamine-anti-IgG). The
anti-CEACAM5 antibody, labetuzumab (hMN-14), was supplied by
Immunomedics and served as an isotype control. Cell culture media
and supplements, fluorescein isothiocyanate-conjugated DNase I
(FITC-DNase I), Alexa Fluor 488 conjugated annexin V (488-annexin
V), tetramethylrhodamine/ethyl ester (TMRE), and
2',7'-dichlorodihydrofluorescein diacetate (CM-H.sub.2DCF-DA), were
supplied by Invitrogen (Grand Island, N.Y.). Rhodamin phalloidin
was obtained from Cytoskeleton, Inc. (Denver, Colo.). One Solution
Cell Proliferation assay reagent was obtained from Promega
(Madison, Wis.). Phosphosafe and RIPA buffers were procured from
EMD chemicals (Billerica, Mass.). Latrunculin B (LatB),
Jasplakinolide (JP), and all other chemicals were obtained from
Sigma-Aldrich (St. Louis, Mo.).
[0196] Immobilization of Epratuzumab.
[0197] To prepare the Dried-I format, epratuzumab in the form of
IgG or F(ab').sub.2 at the indicated concentrations in bicarbonate
buffer (50 mM; pH 9.6) was added to non-tissue-culture flat-bottom
or U-bottom plates as specified, and incubated at 4.degree. C.
overnight, followed by washing with 2.times. RPMI-1640 medium
containing 5% fetal bovine serum (FBS) on the next day before use.
Control antibodies were immobilized in the same fashion. To prepare
the Dried-II format, 2 mL of HUV-EC-C cells (1.5.times.10.sup.4/mL)
were added to 6-well, tissue-culture-treated flat-bottom plates,
incubated overnight, and washed before use. To prepare the
Particulate-I format, epratuzumab (50 .mu.g) was conjugated to 200
.mu.L of carboxyl polystyrene particles (3.0 to 3.4 .mu.m, 5% w/v;
Spherotech, Lake Forest, Ill.) in 1 mL of 2-(N
morpholino)ethanesulfonic acid buffer containing 20 mg of
1-ethyl-3-(3-dimethylaminopropyl) carbodiimide for 30 min according
to the manufacturer's protocol. Conjugated particles were washed
3.times. with PBS and reconstituted with 200 .mu.L of PBS
containing 0.05% bovine serum albumin (BSA) for use as the stock
solution. To prepare the Particulate-II format, FAST FLOW
Immobilized rProtein A (40 to 165 .mu.m; Repligen, Waltham, Mass.)
was incubated with 100 .mu.L of epratuzumab (1 mg/mL) and
supernatants were analyzed to estimate the amounts of epratuzumab
noncovalently linked to the SEPHAROSE.RTM. beads. The resulting
epratuzumab-bound beads were washed 3.times. with
phosphate-buffered saline (PBS) and reconstituted in 100 .mu.L of
the RPMI-1640 medium.
[0198] Cell Culture and Cytotoxicity Assay.
[0199] Cell lines were cultured in RPMI-1640 medium supplemented
with 10% heat-inactivated FBS, L-glutamine (2 mM), penicillin (200
U/mL), and streptomycin (100 .mu.g/mL) in a humidified incubator at
37.degree. C. with 5% CO.sub.2. To evaluate the functional activity
of epratuzumab in the Dried-I format, different amounts of IgG
(starting from 20 .mu.g/mL with 5-fold serial dilution to 0.01
ng/mL) were immobilized in non-tissue-culture-treated, U-bottom,
96-well plates overnight. Daudi cells (1.times.10.sup.4 cells per
well) were seeded and incubated for 3 days. For D1-1 and Ramos
cells, IgG or F(ab').sub.2 of epratuzumab at 5, 10, and 20 .mu.g/mL
was immobilized in 48-well plates overnight. After washing, cells
were seeded (1.times.10.sup.4 cells per well) and incubated for 4
days. The number of viable cells was then determined using the MTS
assay per the manufacturer's protocol, and plotted as percent of
the untreated. Activity of soluble epratuzumab and anti-IgM also
was evaluated in parallel.
[0200] Annexin V Binding Assay.
[0201] Cells in 6-well plates (2.times.10.sup.5 cells/well) were
treated for 24 or 48 h with epratuzumab immobilized to polystyrene
beads (Particulate-I) or plates (Dried-I), washed, resuspended in
100 .mu.L of annexin-binding buffer, stained with 5 .mu.L of
488-annexin V and 0.5 .mu.L of 7-aminoactinomycin D (7-AAD) for 20
min, added 400 .mu.L of annexin-binding buffer, and analyzed by
flow cytometry (FACSCALIBUR.TM.; Becton Dickinson, San Jose,
Calif.). Alternatively, cells were resuspended in 100 .mu.L of
annexin-binding buffer, stained with 5 .mu.L of 488-annexin V for
20 min, added 400 .mu.L of annexin-binding buffer containing 7-AAD,
and analyzed. When required, cells were pretreated with the
indicated inhibitors for 2 h before adding the test article.
[0202] Immunoblot Analysis.
[0203] Daudi, D1-1 or Ramos cells (2.times.10.sup.7 cells) were
added to plates coated with epratuzumab (10 .mu.g/mL) and incubated
for the indicated times. Cells were washed with PBS, lysed in
ice-cold PHOSPHOSAFE.TM. buffer, and the lysates clarified by
centrifugation at 13,000.times.g. Protein samples (25 .mu.g/lane)
were resolved by SDS-PAGE on 4-20% gradient tris-glycine gels,
followed by transfer onto nitrocellulose membranes, and probed with
appropriate antibodies.
[0204] Immunoprecipitation.
[0205] D1-1 cells (5.times.10.sup.6 cell/well) in 6-well plates
were incubated with test articles for the indicated times. After
lysing the cells in ice-cold RIPA buffer, immunoprecipitation was
performed using phospho-tyrosine antibody (4G10; 1:200 dilution).
Samples (20 .mu.L) were separated by SDS-PAGE and transferred onto
a nitro-cellulose membrane, followed by probing with the indicated
antibodies.
[0206] Isolation of Lipid Rafts.
[0207] Lipid rafts were prepared as described previously (Sieger et
al., 2013, Arthritis Rheum 65:770-79). Briefly, cells
(5.times.10.sup.7) were untreated or treated for 2 h with various
test articles and lysed in 1 mL of cell lysis buffer (Cell
Signaling, Danvers, Mass.) containing 1% Triton and 1% protease
inhibitor cocktail on ice for 30 min. The lysates were transferred
to ultracentrifuge tubes, mixed with 1 mL of 80% sucrose in lysis
buffer, overlaid with 5 mL of 35% sucrose and 4.5 mL of 5% sucrose,
then centrifuged at 50,000 rpm (200,000.times.g) for 3 h at
4.degree. C. Fractions of 1 mL were collected from the top, the
protein concentration of each fraction determined with the Bio-Rad
protein assay kit, and 20 .mu.g sample of each fraction was
resolved by 12-20% SDS-PAGE, followed by immunoblots with
appropriate antibodies.
[0208] Measurement of .DELTA..psi..sub.m and ROS.
[0209] Daudi or D1-1 cells (2.times.10.sup.5 cells/well) were
incubated for 48 h with test articles as indicated), washed,
stained with either TMRE (50 nM) or CM-H.sub.2DCF-DA (1 .mu.M) for
30 min in the dark at 37.degree. C., washed 3.times. with PBS, and
analyzed by flow cytometry for .DELTA..psi..sub.m or ROS,
respectively, as described previously (Gupta et al., 2010, Blood
116:3258-67).
[0210] Immunofluorescence Microscopy.
[0211] Daudi cells (2.times.10.sup.6 per sample), were pretreated
with test articles as indicated at 37.degree. C. for 1 h, incubated
with or without LatB for 5 min, washed, fixed, permeabilized with
4% formalin and 0.1% Triton-100, and stained with
Rhodamin-phalloidin and FITC-DNase I for 30 min in the dark at room
temperature. Cells were then washed, resuspended in mounting
solution containing DAPI, and examined by fluorescent
microscopy.
[0212] Calcium Mobilization Assay.
[0213] Daudi cells were loaded with Fluo-3 AM and Fura Red AM dye
for 30 min at room temperature in the dark. For measurement of
intracellular calcium flux, cells were washed 2.times. with an
assay buffer comprising HBSS (1.25 mM CaCl.sub.2, 10 mM HEPES, 1%
BSA), and resuspended in the same buffer, from which 1 mL
(2.times.10.sup.6 cells) was dispensed into each vial and incubated
with a test antibody (20 .mu.g/mL) or the Dried-I format of
immobilized epratuzumab (20 .mu.g/mL) as indicated, for 1 h at
37.degree. C. All samples were kept on ice until analysis. Baseline
fluorescence from each sample was monitored for 1 min before
stimulating with anti-IgM (25 .mu.g/mL), and the signal collected
for the next 8 min. To monitor calcium influx, cells were washed
with HBSS buffer (no Ca.sup.2+, 10 mM HEPES, 1% BSA, 1.5 mM EGTA),
baseline was recorded for 1 min before stimulating with anti-IgM
(25 .mu.g/mL). After 4 min, 5 mM CaCl.sub.2 was added to the sample
and the signal continuously monitored for another 6 min. The ratio
of the geometric mean fluorescence intensity of fluo-3 (Em 530/30
nm) to Fura Red (Em 610/20 nm) was plotted against time and
analyzed by Flowjo software.
[0214] Statistical Analysis.
[0215] Data obtained from in vitro studies were plotted using Prism
software (version 4.03). Comparisons of mean values between two
treatments were determined by Student's t-test, assuming a normal
distribution for the data. A two-tailed t-test was used when
comparing different samples. P<0.05 was considered statistically
significant.
[0216] Results
[0217] Inhibition of Proliferation and Induction of Apoptosis.
[0218] To evaluate the effect on cell proliferation, varying
amounts of epratuzumab were coated on non-tissue-culture, U-bottom
plates, and the results of the MTS cell viability assay indicate
that at 5 .mu.g/mL, immobilized epratuzumab of the Dried-I format
could inhibit about 60% proliferation of D1-1 cells compared to
untreated cells (P<0.005), with little change found at higher
concentrations of 10 and 20 .mu.g/mL (FIG. 1A). In Ramos cells,
which express a lower level of CD22 than D1-1, epratuzumab achieved
about 45% growth-inhibition when coated at 10 .mu.g/mL compared to
untreated cells (P<0.005). Immobilized labetuzumab
(anti-CEACAM5), serving as an isotype control of the Dried-I
format, did not induce appreciable growth-inhibition in either cell
line (FIG. 1A). Soluble epratuzumab (the Wet-I format), even at the
highest concentration (20 .mu.g/mL) tested, did not induce
growth-inhibition in both cell lines (FIG. 1B), indicating the
requirement for immobilization.
[0219] Evidence that immobilization of epratuzumab was required to
induce apoptosis was provided by the Particulate-I format (Table 2)
of bead-conjugated epratuzumab (FIG. 1C), which, at both 5- and
20-.mu.L doses, caused about 75% apoptosis in D1-1 cells following
a 24-h incubation, as compared to approximately 20% (P<0.005)
for the three controls (cells with no treatment, cells treated with
soluble epratuzumab, and cells treated with unconjugated beads).
The same particulate epratuzumab also resulted in about 30%
apoptosis in Ramos cells, which was significant (P<0.005)
compared with the three controls (10% apoptosis). Similar results
were obtained with the Dried-I format of epratuzumab F(ab').sub.2
in D1-1 cells, as shown in FIG. 1D for apoptosis (left panel;
P<0.05 vs. controls) and growth inhibition (right panel;
P<0.025 vs. controls), indicating a lack of Fc involvement in
the cytotoxicity of plate-immobilized epratuzumab.
[0220] Further experiments in Daudi cells demonstrated that the in
vitro cytotoxicity of epratuzumab, as determined by the MTS assay,
could be observed dose-dependently with the Dried-I or the Wet-III
format (FIG. 2A, right panel), but not with the Wet-I or the
Wet-IIB format (FIG. 2A, left panel), and confirmed that the
Dried-I format induced apoptosis comparable to the positive control
of anti-IgM as determined by the Annexin V assay (FIG. 2B). More
importantly, we have discovered that the Dried-II format, which
employed plates coated with a monolayer of HUV-EC, was capable of
inducing apoptosis in Daudi cells in the presence of soluble
epratuzumab to a similar extent (.about.50%), when compared with
the Dried-I format (FIG. 2C).
[0221] Phosphorylation of CD22, CD79a and CD79b.
[0222] To elucidate the differential effect induced on D1-1 or
Ramos cells by soluble (in various Wet-based formats) and
immobilized (the Dried-I format) epratuzumab, we evaluated their
roles in phosphorylating CD22, CD79a, and CD79b, and compared the
results with those of anti-IgM. As shown in FIG. 3A (left panel)
for D1-1 cells, soluble anti-IgM at 10 .mu.g/mL induced
phosphorylation of CD22, CD79a and CD79b, while soluble epratuzumab
(lane: hLL2/Wet-I) induced notable phosphorylation of CD22 and some
CD79b, but not CD79a. In contrast, FIG. 3A (right panel) shows
immobilized epratuzumab (lane: hLL2*/Dried-I), and immobilized
anti-IgM (lane: anti-IgM*) as well, induced phosphorylation of
CD22, CD79a and CD79b to a similar extent. However, whereas the
Wet-III format of epratuzumab (FIG. 3B, lane 7), comprising a
mixture of hLL2 (7.5 .mu.g/mL), GAH (10 .mu.g/mL) and anti-IgM (1
.mu.g/mL), induced the phosphorylation of CD22, CD79a, and CD79b as
soluble anti-IgM at 10 .mu.g/mL (FIG. 3B, lane 8), omitting one or
two components from the Wet-III format (FIG. 3B, lanes 2-5), or the
provision of only a very small amount of hLL2 (10 ng/mL) to GAH and
anti-IgM (FIG. 3B, lane 6), failed to induce phosphorylation of all
three molecules. These results correlate the observed cytotoxicity
of anti-IgM (10 .mu.g/mL) and epratuzumab presented in the Dried-I
or Wet-III format with their ability to simultaneously
phosphorylate CD22, CD79a, and CD79b in target cells.
[0223] Translocation of CD22 and CD79 to lipid rafts. Treatment of
Daudi cells with anti-IgM (10 .mu.g/mL) or epratuzumab either in
the Dried-I format (FIG. 3C, left panel; sample: hLL2*) or the
Wet-I format (FIG. 3C, left panel; sample: hLL2) all resulted in
the redistribution of CD22 to the lipid rafts (fractions 3-6, FIG.
8). However, redistribution of CD79b to lipid rafts (FIG. 3C, right
panel) was observed only with anti-IgM or the Dried-I format
(sample: hLL2*), but not with the Wet-I format (sample: hLL2).
Additional experiments also revealed that only CD22, not CD79a or
CD79b, could be detected in lipid rafts from cells treated with
soluble epratuzumab either in the Wet-I (FIG. 3D, lane 2) or the
Wet-IIA format (FIG. 3D, lane 5). These results confirm the ability
of soluble epratuzumab (the Wet-I format) to stabilize the
localization of CD22 in lipid rafts (Qu et al., 2008, Blood
111:2211-19), and suggest that the cytotoxicity of epratuzumab
requires the concurrent translocation of CD22, CD79a, and CD79b to
lipid rafts.
[0224] Activation of BCR-Mediated Signals and Modulation of MAP
Kinases.
[0225] The Dried-I format of epratuzumab induced in DI-1 cells
rapid and prolonged phosphorylation of Lyn, Syk, and PLC.gamma.2,
as shown in FIG. 4A. Changes of intracellular signals induced by
the Dried-I format also included a rapid (detectable within 30 min)
and continuous (over a period of 24 h) activation of both ERKs and
JNKs (FIG. 4B). A functional role of JNK was established by showing
SP600125, a known inhibitor of INK, given at low doses (2.5 and 5
nM) to D1-1 cells 2 h before treatment with plate-immobilized
epratuzumab, could effectively prevent apoptosis when determined at
24 h (FIG. 4C).
[0226] Caspase-Mediated Apoptosis.
[0227] The effect of the Dried-I format on the basal levels of
selective pro-apoptotic and anti-apoptotic proteins, was evaluated
in D1-1 cells following treatment for 24, 48 and 72 h. As shown in
FIG. 4D, the Dried-I format (sample: hLL2*) downregulated
anti-apoptotic Bcl-xL and Mcl-1, while increasing the expression
level of pro-apoptotic Bax; the results pertaining to Bcl-2 were
less certain, however. The observed cleavage of caspase 3, caspase
9 and poly ADP ribose polymerase (PARP), as shown in FIG. 4E,
indicates the Dried-I format orchestrates a caspase-dependent
apoptosis in D1-1 cells, which could be reduced from about 40% to a
level similar to the untreated cells (about 15%) by the pan-caspase
inhibitor, Z-VAD-fmk, at 10 or 25 .mu.M (P<0.02), as shown in
FIG. 4F. It is noted that untreated controls shown in FIG. 4D and
FIG. 4E were taken at the 72-h time-point, and there was no change
in untreated samples when examined at either 24 h or 48 h.
[0228] Decrease in .DELTA..psi..sub.m and Generation of ROS.
[0229] In FIG. 5A, the Dried-I format (sample: hLL2*) was shown to
induce mitochondrial membrane depolarization, manifested as a
decrease in .DELTA..psi..sub.m, in about 45% of D1-1 cells, whereas
no more than 20% of cells with comparable changes could be detected
in the five controls. Similar results were observed for the Dried-I
format in Ramos cells (data not shown) and in about 60% of Daudi
cells treated with the Dried-I format (FIG. 5B, subpanel: hLL2*) or
the Dried-II format (FIG. 5B, subpanel: HUV-EC/hLL2), which
replaced plate-immobilized epratuzumab with soluble epratuzumab and
plate-coated HEV-EC. To corroborate such findings, both the Dried-I
(FIG. 5C, subpanel: hLL2*) and the Dried-II (FIG. 5C. subpanel:
HUV-EC/hLL2) formats increased the generation of ROS in about 30%
of the cells, as compared to about 6% in the untreated control, and
about 9 to 10% in cells incubated with the Wet-I format (FIG. 5C,
subpanel: hLL2), isotype control of the Dried-I format (FIG. 5C,
subpanel: hMN-14*) or HEV-EC in the absence of epratuzumab (FIG.
5C, subpanel: HUV-EC).
[0230] Effect on Calcium Mobilization and Actin Dynamics.
[0231] In Daudi cells, pretreatment with either the Wet-I or the
Dried-I format for 1 h notably reduced the amplitude of calcium
ions released from intracellular stores following stimulation with
anti-IgM, with a larger effect incurred by the plate-immobilized
than the soluble epratuzumab; however, the subsequent entry of
extracellular calcium was minimally affected (FIG. 6A). The
ligation of CD22 by plate-immobilized epratuzumab appeared to
stabilize F-actin from depolymerization by LatB, when analyzed at 5
min after the addition of LatB, as evidenced by the prominent
staining of F-actin by rhodamin phalloidin, which was absent in the
untreated Daudi cells, as shown in FIG. 6B. Additional results
shown in FIG. 6C indicate that the addition of LatB did not affect
the staining of F-actin in cells pretreated with hLL2*, but
demolished the staining of F-actin in cells treated with soluble
epratuzumab or the isotype control of the Dried-I format
(hMN-14*).
DISCUSSION
[0232] In the present study, we confirmed that ligation of mIgM by
a sufficient amount of anti-IgM (10 .mu.g/mL) induced the
phosphorylation of CD22, CD79a and CD79b, and the localization of
all three phosphorylated proteins in lipid rafts, leading to cell
death in D1-1, a subline of Daudi selected for a higher expression
of mIgM. We further show that ligation of CD22 with
plate-immobilized epratuzumab (the Dried-I format) induced a
similar change in CD22, CD79a and CD79b, including phosphorylation,
translocation into lipid rafts, and subsequent cell death. Thus, it
appears that for a CD22-binding agent such as epratuzumab to kill
Daudi cells in particular, and perhaps other CD22-expressing B-cell
lymphomas, two critical events must occur in concert, (i)
phosphorylation of CD22, CD79a and CD79b above a threshold level,
and (ii) their movement to lipid rafts. This conclusion is
supported by the finding that little or no cell death was observed
for D1-1 cells with the Wet-II format comprising a secondary
crosslinking GAH antibody at 10 .mu.g/mL and either soluble
epratuzumab at 7.5 .mu.g/mL or a suboptimal amount of anti-IgM (1
.mu.g/mL). The former treatment efficiently induced phosphorylation
of CD22 and its localization to lipid rafts (FIG. 3D, lane 5), but
was unable to phosphorylate CD79a and CD79b (FIG. 3B, lane 4),
whereas the latter treatment failed to phosphorylate CD22, CD79a
and CD79b to a detectable level (FIG. 3B, lane 6). On the other
hand, combining these two treatments in the Wet-III format could
result in phosphorylation of CD22, CD79a and CD79b (FIG. 3B, lane
7), their localization into lipid rafts (FIG. 3D, lane 4), and
consequently, cell death, as observed for anti-IgM at 10 .mu.g/mL
or the Dried-I format of epratuzumab.
[0233] Binding of CD22 to beads coated with B3 antibody (a murine
anti-hCD22 mAb) was reported to lower the threshold concentration
of anti-IgM required for stimulating DNA synthesis in tonsillar B
cells by two orders of magnitude, presumably due to sequestration
of CD22 from mIgM by restricting the lateral movement of CD22 in
the plane of the cell membrane (Doody et al., 1995, Science
269:242-33). Our results show, however, that the ability of
high-density, plate-immobilized or bead-conjugated epratuzumab to
engage CD22 along with co-clustering, rather than sequestration, of
mIgM, constitutes a sufficient condition for cell killing in the
total absence of anti-IgM, which may be further strengthened by the
co-localization of both mIgM and CD22 in lipid rafts. Moreover, the
binding of immobilized epratuzumab to CD22 is distinctive from that
of a synthetic .alpha.2,6-linked sialic acid, which efficiently
prevented CD22 from co-capping and co-localization with BCR in the
lipid rafts after BCR ligation (Yu et al., 2007, Biochem Biophys
Res Commun 360:759-64).
[0234] Intriguingly, we did not observe any transient increase in
intracellular calcium by immobilized epratuzumab in the
Particulate-I format, but have noted a substantial decrease of
anti-IgM-induced mobilization of intracellular calcium in Daudi
cells pretreated with either the Dried-I or the Wet-I format of
epratuzumab for 1 h. These results are consistent with two previous
findings: one reporting that a copolymer comprising multiple copies
of 2,4-dinitrophenyl (DNP) and a synthetic CD22 ligand (CD22L),
which was capable of trans-binding to CD22 via colligation with BCR
in a murine B cell line displaying a DNP-specific BCR, failed to
induce any calcium flux (Courtney et al., 2009, Proc Natl Acad Sci
USA 106:2500-05); the other reporting that preincubating B cells
with the IgG or F(ab').sub.2 of epratuzumab reduced the amplitude
of calcium mobilization stimulated by anti-IgM/IgG (Sieger et al.,
2013, Arthritis Rheum 65:770-79). Thus, when both CD22 and BCR are
co-clustered by immobilized epratuzumab or the DNP-CD22L copolymer,
calcium signals resulting from BCR stimulation can be partially or
completely suppressed, which is in contrast to the enhanced calcium
flux found in B cells pretreated with certain anti-CD22 antibodies
upon BCR activation, often attributed to sequestration of CD22 from
BCR (Rudge et al., 2002, J Exp Med 195:1079-85; Chan et al., 1998,
Curr Biol 8:545-53). Although certain intracellular events observed
for the Dried-I format of epratuzumab and the DNP-CD22L copolymer
were similar, such as a more sustained phosphorylation of CD22 and
Lyn, differences in their opposing effect on pSyk and pPLC.gamma.2
also should be noted.
[0235] Whereas the ability of an anti-mIg to induce calcium flux
may or may not lead to cell death in B-cell lymphoma, as reported
for B104 (Ishigami et al., 1992, J Immunol 148:360-68), a human
B-cell lymphoma line expressing BCR of both mIgM and mIgD, we show
with the Dried-I format of immobilized epratuzumab that potent
inhibition of cell proliferation with apoptosis also can be
independent of calcium mobilization. Thus, besides the routine
measurement of intracellular calcium as a marker for B-cell
activation and cell surface binding to assess the affinity for
CD22, the biological significance of CD22-targeting agents,
particularly those derived from synthetic sialosides (Yu et al.,
2007, Biochem Biophys Res Commun 360:759-64; Courtney et al., 2009,
Proc Natl Acad Sci USA 106:2500-05; O'Reilly et al., 2008, J Am
Chem Soc 130:7736-46; Abdu-Allah et al., 2008, J Med Chem
51:6665-81; Abdu-Allah et al., 2011, Bioorg Med Chem 19:1966-71),
should be substantiated with a suitable cytotoxicity assay, as
exemplified by the capability of liposomal nanoparticles displaying
both antigen and CD22L to induce antigen-specific B-cell apoptosis
(Macauley et al., 2013, J Clin Invest 123:3074-83).
[0236] Despite their difference in calcium mobilization,
resemblances of anti-IgM and immobilized epratuzumab were revealed
in several intracellular events, including caspase-dependent
apoptosis, reduced .DELTA..psi..sub.m, generation of ROS, and a
similar profile of phosphorylated Lyn, Syk, PLC.gamma.2, ERKs and
JNKs. Moreover, the novel observation that some of the in vitro
effects displayed by the Dried-I format of immobilized epratuzumab,
including apoptosis, drop in .DELTA..psi..sub.m, and generation of
ROS, could be induced by co-cultivation of Daudi cells with HUV-EC
in the presence of soluble epratuzumab (the Dried-II format)
implies a physiological relevance of immobilized epratuzumab.
Collectively, the present data support the hypothesis that the
non-ligand-blocking epratuzumab may act in vivo by unmasking CD22
to facilitate the trans-interaction of B cells with vascular
endothelium (FIG. 7A), thereby inducing the various in vitro
effects of immobilized epratuzumab. Noting that cytokine-activated
human endothelial cells (EC) express enhanced levels of CD22L
(Hanasaki et al., 1994, J Biol Chem 269:10637-43) and can adhere to
B cells whose endogenous binding of CD22 to CD22L have been
disrupted (Hanasaki et al., 1995, J Biol Chem 270:7533-42), one
scenario, as depicted in FIG. 7B, would be the immobilization of
the immune complexes comprising epratuzumab and B cells to the
endothelium via the association of CD22 on B cells with the
CD22L-containing glycoproteins on EC. Because human EC also express
CD32A (Fc.gamma.RIIA) (Groger et al., 1996, J Immunol 156:1549-56;
Pan et al., 1998, Clin Exp Immunol 112:533-38), an alternative
explanation (FIG. 7C) would be the immobilization of the
epratuzumab-B cell complex to the endothelium via the association
of the Fc domain on epratuzumab with CD32A on EC. These two
possibilities are not mutually exclusive, with both likely
occurring in vivo, and provide a plausible mechanism mediated by
epratuzumab that enables the strong interaction between B cells and
EC due to concurrent engagement of multiple cell surface molecules
present on both types of cells.
[0237] Knowing that binding of CD22 by soluble epratuzumab leads to
internalization raises the question whether internalization of CD22
plays a role in the mechanism of cell killing. Taking a cue from
CD20, which also interacts with BCR and affects calcium
mobilization and its own degradation (Walshe et al., 2008, J Biol
Chem 83:16971-84), the expression levels of CD22 as well as BCR on
the cell surface may be critical for the activity of anti-CD22
mAbs. On the other hand, we speculate that immobilized epratuzumab
may delay or prevent the internalization of BCR or CD22, or both,
by changing actin dynamics and stabilizing the co-localized CD22
and BCR in the lipid rafts, leading to functional inactivation of
BCR.
[0238] In conclusion, we provide evidence for the mechanism of
action by which immobilized epratuzumab induces cytotoxic and
cytostatic effects in CD22-expressing B-lymphoma lines with BCR of
the IgM isotype. Our findings add to the existing knowledge that
immobilized antibodies, such as those directed at CD3 (Geppert
& Lipsky, 1987, J Biol Chem 138:1660-66), CD47 (Mateo et al.,
1999, Nat Med 5:1277-84), or CD40 (Watanabe et al., 2003, J Immunol
171:5828-36), display different biological ability on target cells
from their soluble counterparts, and establish that ligation of
CD22 by immobilized epratuzumab perturbs BCR-mediated signals in
malignant B cells without the involvement of anti-BCR antibodies.
We also uncover, for the first time, a role of immobilized
epratuzumab to stabilize F-actin and the potential of soluble
epratuzumab to promote the adhesion of B cells to endothelial
cells, which may occur in vivo to manifest the various biological
activities observed for the immobilized epratuzumab in vitro. Since
plate- or bead-immobilized epratuzumab may represent a surrogate
in-vitro mechanism of antibody crosslinking in vivo, the current
study suggests that other agents comprising multiple epratuzumab
molecules are worth investigating, such as CD22-targeting
immunoliposomes. These can be generated to provide a high number of
epratuzumab molecules on the surface of each liposome, as has been
shown for immunoliposomes comprising the anti-HER2 trastuzumab
(Chiu et al., 2007, Mol Cancer Ther 6:844-55), anti-CD74
milatuzumab (Hertlein et al., 2010, Blood 116:2554-58), or an
anti-transferrin receptor antibody (Wang et al., 2010, J Am Chem
Soc 132:11306-13).
TABLE-US-00006 TABLE 2 In vitro conditions to evaluate the
cytotoxicity of epratuzumab on CD22-expressing B cells. Conditions
Format Target cells + epratuzumab IgG immobilized onto Dried-I
microtiter wells overnight Target cells + labetuzumab IgG
immobilized onto Isotype control microtiter wells overnight for
Dried-I Target cells + epratuzumab IgG over a monolayer of Dried-II
HUV-EC Target cells + labetuzumab IgG over a monolayer of Isotype
control HUV-EC for Dried-II Target cells + epratuzumab IgG or
F(ab').sub.2 in solution Wet-I Target cells + epratuzumab IgG + GAH
in solution Wet-IIA Target cells + epratuzumab IgG + anti-IgM (1
.mu.g/mL) Wet-IIB in solution Target cells + epratuzumab IgG + GAH
+ anti-IgM Wet-III (1 .mu.g/mL) in solution Target cells +
epratuzumab IgG conjugated to Particulate-I polystyrene beads
Target cells + epratuzumab IgG bound to Protein Particulate-II
A-Sepharose Target cells + anti-IgM (10 .mu.g/mL) in solution
Positive control
Example 2. Epratuzumab-Induced Trogocytosis of BCR-Response
Modulating Proteins Ex Vivo
[0239] The humanized anti-CD22 antibody, epratuzumab, has
demonstrated therapeutic activity in clinical trials of patients
with non-Hodgkin lymphoma (NHL), acute lymphoblastic leukemia,
primary Sjogren's syndrome, and systemic lupus erythematosus (SLE).
Thus, epratuzumab offers a promising option for CD22-targeted
immunotherapy of B-cell lymphomas and autoimmune diseases. However,
its mechanism of action (MOA) remains incompletely understood
to-date. Because epratuzumab has modest, but significant,
antibody-dependent cell-mediated cytotoxicity and negligible
complement-dependent cytotoxicity when evaluated in vitro, and its
moderate depletion of circulating B cells in patients (35% on
average) may be overestimated due to use of CD19.sup.+ cells to
measure B cells by flow cytometry (discussed below), the
therapeutic action of epratuzumab in vivo may not result from
B-cell depletion. We investigated whether ligation of epratuzumab
to CD22 could modulate other surface molecules on B cells. In
particular, we focused on those surface molecules involved in
regulating antigen-specific B-cell receptor (BCR) signaling, since
modulation of such molecules may lead to altered B-cell functions
that ultimately mitigate symptoms of autoimmune or other diseases.
With regard to its function of killing malignant B cells expressing
CD22, our studies have shown that these effects are more related to
the BCR signaling pathway than effector-cell function.
[0240] Here we report for the first time that epratuzumab induces a
substantial reduction of CD22, along with CD19, CD21, CD20, and
CD79b, on the surface of B cells in peripheral blood mononuclear
cells (PBMCs) obtained from normal donors or lupus patients, and
three NHL Burkitt cell lines (Daudi, Raji, and Ramos) spiked into
normal PBMCs. The intriguing observation that only CD22, but not
other surface markers, was appreciably decreased by epratuzumab in
isolated NHL cells prompted us to assess the role of
Fc.gamma.R-bearing effector cells, with the finding that
epratuzumab effectively mediates trogocytosis [a process whereby
cells binding to antigen-presenting cells extract surface molecules
from these cells and express them on their own surface] of multiple
surface proteins from B cells to monocytes, NK cells, and
neutrophils. This mechanism of action may explain the limited
effectiveness of high doses of epratuzumab compared to lower doses
in patients with SLE.
[0241] Peripheral blood mononuclear cells (PBMCs) obtained from
healthy donors were incubated overnight (16-24 h) with 10 .mu.g/mL
of either epratuzumab or an isotype control mAb (hMN-14) and the
relative levels of various antigens on the surface of the B cells
were analyzed by flow cytometry. PBMCs from heparinized whole blood
of normal donors were isolated by density gradient centrifugation
on UNI-SEP tubes (Novamed Ltd, Israel). PBMCs were reconstituted in
RPMI media supplemented with 10% heat inactivated fetal bovine
serum and plated at a cell density of 1.5.times.10.sup.6/mL in
non-tissue culture treated 48-well plates. Epratuzumab or hMN-14
were added to triplicate wells at a final concentration of 10
.mu.g/mL and incubated overnight (16-20 h) before staining with
fluorescent-labeled primary antibodies (Biolegend) following the
manufacturers suggested protocols. Stained cells were analyzed by
flow cytometry on a FACSCALIBUR.RTM. (BD Biosciences) using Flowjo
(V7.6.5) software. Initially, the lymphocyte population was gated
by side vs. forward scattering, and B cells were further gated from
this population with the CD19 signal. The mean fluorescence
intensity (MFI), obtained with fluorochrome-conjugated antibodies
to various cell surface antigens, on the gated B cells was
calculated following treatment with epratuzumab, hMN-14 or without
antibody. PBMCs from 16 healthy donors were assessed in various
experiments.
[0242] Treatment with the control mAb (hMN-14) did not affect the
levels of any of the tested proteins and resulted in MFI
measurements that were very similar to untreated samples.
Alternatively, epratuzumab significantly reduced the levels of key
BCR-regulating proteins, including CD22, CD19, CD21 and CD79b,
which were reduced to 10, 50, 52 and 70%, respectively, of the
level of untreated or control mAb (not shown). CD20 (82%) and CD62L
(73%) also were reduced, but to a lesser extent. Other surface
proteins including CD27 (on CD27.sup.+ B cells), CD40, CD44, CD45,
.beta.7 integrin and LFA-1 (CD11a and CD18) were affected minimally
(<10% change) by epratuzumab. CD27.sup.- naive B cells were more
responsive to epratuzumab compared to CD27.sup.+ memory B cells, as
shown with PBMCs as shown for CD19 from 3 different healthy donors
(not shown). CD22, CD21 and CD79b were also reduced to a greater
extent on CD27.sup.- cells (not shown). The effect was essentially
complete within a few hours. The reductions in surface CD19 and
CD21 were not significantly different following 2-h or overnight
treatment (not shown).
Example 3. Dose-Dependent Trogocytosis with Epratuzumab
[0243] The effect of epratuzumab on the cell surface levels of
CD19, CD21, CD22 and CD79b was compared using the standard (10
.mu.g/mL) concentration with a 100-fold higher concentration (1
mg/mL). An additional treatment included 10 .mu.g/mL epratuzumab
combined with 1 mg/mL hMN-14. Compared to the lower concentration
of epratuzumab (10 .mu.g/mL), the higher concentration (1 mg/mL)
resulted in significantly (P<0.02) less reduction in CD22, CD19,
CD21 and CD79b (not shown). Competition with high concentration (1
mg/mL) hMN-14 significantly (P<0.003) reduced the effect of
epratuzumab (10 .mu.g/mL) on CD22 and CD19, but to a lesser extent
than high-dose epratuzumab. A titration experiment, where normal
PBMCs were incubated overnight with epratuzumab at concentrations
ranging from 0.1-1000 .mu.g/mL, confirmed that doses approaching 1
mg/mL dampened the effect (not shown). A second titration covering
8 logs (1 ng/mL-10 mg/mL) produced a classic U-shaped curve with
substantial dampening at concentrations lower than 10 ng/mL or
greater than 1 mg/mL (not shown). The reduction of both CD22 and
CD19 on B cells within PBMCs was similar over a wide concentration
range (10 ng/mL-100 .mu.g/mL) of epratuzumab.
Example 4. Effector Cells are Required for Epratuzumab-Induced
Trogocytosis
[0244] B cell lymphoma cell lines were used as "isolated B cells"
that were evaluated for epratuzumab induced trogocytosis. In vitro,
epratuzumab induced an intermediate reduction (33% control) of CD22
on the surface of isolated Daudi Burkitt lymphoma cells, and did
not affect the levels of other markers (not shown). In an ex vivo
setting, where Daudi were spiked into PBMCs from a healthy donor,
epratuzumab minimized CD22 (<5% control) and significantly
(P<0.0001) reduced CD19 (28% control), CD21 (40% control), CD79b
(72% control) and surface IgM (73% control). Similar results were
obtained with Raji lymphoma cells, where CD19, CD21 and CD79b were
diminished by epratuzumab only in the presence of PBMCs (not
shown). The addition of a crosslinking second antibody resulted in
only a modest reduction of CD19, CD21 and CD79b. That the effect
only was observed in the presence of PBMCs, and it was not
accomplished in the presence of PBMCs with a F(ab').sub.2 fragment
or with a crosslinking second antibody in place of PBMCs, indicates
that effector cells bearing Fc receptors are involved in the
epratuzumab-induced trogocytosis process.
Example 5. Monocytes, but not T Cells can Modulate
Epratuzumab-Induced Trogocytosis
[0245] Combined, T cells and monocytes comprise approximately
70-80% of the total PBMCs. The ability of PBMC fractions, which
were depleted of either T cells or monocytes using MACS separation
technology (Miltenyi Biotec) with magnetically labeled microbeads
in an LS or MS column, were evaluated for epratuzumab-induced
reduction of CD22 and CD19 on Daudi and normal B cells. For this
experiment the ratio of total effector cells to Daudi was held
constant. Therefore, removal of a specific cell type resulted in
increased numbers of the remaining cell types (not shown).
Depletion of T cells was only 50% efficient; however, this resulted
in a 10% increase in monocytes and other cell types. The
T-cell-depleted PBMCs were significantly more active than total
PBMCs, indicating that T cells are not involved (not shown).
Indeed, purified T cells were not capable of affecting the
epratuzumab-induced reduction of CD19 or CD21 on Daudi (not shown).
Conversely, depletion of monocytes, which was 99% efficient (not
shown), significantly dampened the reduction of both CD19 and CD22
on either Daudi or B cells (not shown), implicating the involvement
of monocytes. That there was appreciable reduction of CD19 with the
monocyte-depleted PBMCs, suggests the participation of additional
cell types. In a subsequent experiment, purified monocytes (94%)
induced a similar decrease in CD19 as the whole PBMCs, whereas the
remaining monocyte-depleted PBMCs had minimal effect, comparable to
the levels measured without effector cells (not shown). A similar
pattern was observed for CD22. This particular donor gave
relatively weak activity (25% reduction in CD19) compared to most
others, where we have typically observed a 40-60% reduction in
CD19. Nonetheless, the results support the key role of monocytes
among PBMCs.
Example 6. Ex Vivo Trogocytosis with SLE Patient PBMC
[0246] PBMCs were isolated from blood specimens of systemic lupus
erythematosus (SLE, lupus) patients, who had yet to receive any
therapy for their disease (naive), and treated ex vivo with
epratuzumab, using the same method that was applied to PBMCs from
healthy donors. PBMCs of naive SLE patients responded similarly to
healthy PBMCs (as in Example 2), where CD22, CD19, CD21 and CD79b
on the surface of B cells were reduced to 11.+-.4, 53.+-.8, 45.+-.4
and 75.+-.1% control, respectively (not shown). Also similar to the
results from normal donor PBMCs, CD2T naive B cells were more
responsive than CD27.sup.+ memory B cells (not shown), and, a
F(ab').sub.2 fragment of epratuzumab did not induce the reduction
of CD19, CD21 or CD79b (not shown). PBMCs isolated from blood
specimens of SLE patients who currently were on epratuzumab
immunotherapy had minimal response to the ex vivo treatment with
epratuzumab (not shown), presumably due to low levels of CD22 on
their B cells, resulting from therapy.
Example 7. Surface Levels of CD19, CD21, CD22 and CD79b on SLE
Patient B Cells on Epratuzumab Immunotherapy
[0247] The relative levels of CD22, CD19, CD21 and CD79b on B cells
from five SLE patients who were receiving epratuzumab
immunotherapy, were compared the results obtained from four naive
lupus patients and two receiving BENLYSTA.RTM., using identical
conditions (Table 3).
TABLE-US-00007 TABLE 3 Comparison of B cells from lupus patients %
B cell in CD19 CD21 CD22 CD79b Patient Treatment lymphgate (PE-Cy7)
(FITC) (FITC) (APC) S7 E, P, M 0.5 99 9 16 186.sup.PE S8 P, I 5.0
145 nd 84 nd S9 B 0.5 218 21 48 470.sup.PE S10 B 0.9 204 20 133
425.sup.PE S11 None 18.0 195 51 106 608 S12 None 13.1 160 44 114
428 S13 None 13.3 206 43 117 510 S14 None 11.1 169 32 146 604 S16
E, P 8.9 128 24 27 452 S17 E, P 4.5 93 16 25 340 S18 E, P 17.6 159
32 18 413 S19 E, P 20.3 155 19 38 349 E, epratuzumab; P,
prednisone; M, methotrexate; I, Imuran; B, BENLYSTA .RTM.; PE, used
instead of APC; nd, not determined
[0248] Only one of the epratuzumab group (S7) had a markedly
reduced B cell count; however, this patient was also taking
prednisone and methotrexate. Each of the four patients on
epratuzumab without methotrexate had B cell counts in the same
range as the naive patients. Both BENLYSTA.RTM. patients had low B
cell counts. As expected, CD22 was significantly (P<0.0001)
lower (>80%) on the B cells of epratuzumab-treated patients (not
shown). Notably, CD19, CD21 and CD79b were each significantly
(P<0.02) lower for the epratuzumab group (not shown). We also
compared the results for the epratuzumab patient specimens with
those of two patients who were receiving immunotherapy with
BENLYSTA.RTM.. Although the sample size is small, both CD19 and
CD22 levels were significantly (P<0.05) lower on the B cells of
patients on epratuzumab compared to BENLYSTA.RTM.. The level of
CD21 was similarly low for the epratuzumab and BENLYSTA.RTM.
patient B cells. Because anti-CD79b-PE (instead of APC) was used to
measure CD79b on B cells from BENLYSTA.RTM. patients, we could only
compare these results with one epratuzumab patient specimen, which
was measured similarly. The CD79-PE MFI was greater for each of the
BENLYSTA.RTM. specimens (MFI=425 and 470) compared to that of the
epratuzumab sample (MFI=186).
[0249] The present studies disclose important mechanisms of action
of epratuzumab in normal and lupus B cells, as well as B-cell
lymphomas, which may be more pertinent to the therapeutic effects
of epratuzumab in autoimmune patients. The prominent loss of CD19,
CD21, CD20, and CD79b induced by epratuzumab is not only
Fc-dependent, but also requires further engagement with
Fc.gamma.R-expressing effector cells present in PBMCs. The findings
of reduced levels of CD19 are of particular relevance for the
efficacy of epratuzumab in autoimmune diseases, because elevated
CD19 has been correlated with susceptibility to SLE in animal
models as well as in patients, and loss of CD19 would attenuate
activation of B cells by raising the BCR signaling threshold. Based
on these findings, the activity of epratuzumab on B cells is via
binding to CD22, which also occurs with F(ab').sub.2, and via
engagement of Fc.gamma.R-bearing effector cells. Whereas the former
leads to internalization of CD22, as well as its phosphorylation
with concurrent relocation to lipid rafts (resulting in the
activation of tyrosine phosphatase to inhibit the activity of Syk
and PLCr2), the latter results in the trogocytosis (shaving) of
CD19, among others.
[0250] We propose that the consequences of losing CD19 from B cells
are as follows. BCR activation upon encountering membrane-bound
antigen involves the initial spreading and the subsequent formation
of microclusters. Because CD19 is critical for mediating B-cell
spreading, CD19-deficient B cells are unable to gather sufficient
antigen to trigger B-cell activation. In addition, loss of CD19 on
B cells may severely affect the ability of B cells to become
activated in response to T cell-dependent antigens. Thus, the
epratuzumab-mediated loss of CD19 (and possibly other BCR markers
and cell-adhesion molecules) on target B cells may incapacitate
such B cells and render them unresponsive to activation by T
cell-dependent antigen. In summary, epratuzumab inactivates B cells
via the loss of CD19, other BCR constituents, and cell-adhesion
molecules that are involved in sustaining B-cell survival, leading
to therapeutic control in B-cell-mediated autoimmune diseases.
Although targeting B cells with either epratuzumab to CD22 or
rituximab to CD20 appears to share a common effect of reducing CD19
by trogocytosis, we are currently investigating whether rituximab
has a scope of trogocytosis as broad as epratuzumab. The results
also caution that using CD19 as a marker for quantifying B cells by
flow cytometry from patients treated with agents that induce CD19
trogocytosis may result in an over-estimation of B-cell
depletion.
[0251] It has been shown with rituximab administered to chronic
lymphocytic leukemia cells that too much antibody results in
removal of complexes of rituximab-CD20 from the leukemia cells by
trogocytosis to monocytes, and can enable these malignant cells to
escape the effects of the antibody by antigenic modulation. It was
then found that reducing the dose of therapeutic antibody could
limit the extent of trogocytosis and improve the therapeutic
effects (Herrera et al., 2006). Based on our present findings, a
similar process of antigen shaving (trogocytosis) by anti-CD22 or
anti-CD20 antibodies that extends beyond the respective targeted
antigens can be implicated in the therapy with epratuzumab or
rituximab (or the humanized anti-CD20 mAb, veltuzumab). This could
explain the clinical observations that higher doses of epratuzumab
administered to SLE or lymphoma patients did not show an
improvement in efficacy over the mid-range dose used, because the
concentrations of epratuzumab in serum would be in the .mu.M range
(150 .mu.g/mL or higher) and could mask the low-affinity
Fc.gamma.Rs on effector cells, thus reducing the likely events of
trogocytosis.
Example 8. Administration of Epratuzumab in Systemic Lupus
Erythematosus (SLE)
[0252] An open-label, single-center study of patients with
moderately active SLE (total British Isles Lupus Assessment Group
(BILAG) score 6 to 12) is conducted. Patients receive dosages of
epratuzumab of 100, 200, 400 and 600 mg subcutaneously (SC) every
week for 6 weeks. Evaluations include safety, SLE activity (BILAG),
blood levels of B and T cells, human anti-epratuzumab antibody
(HAHA) titers, and levels of cell surface CD19, CD20, CD21, CD22
and CD79b on B cells. It is determined that a dosage of 400-600 mg
per SC injection results in optimal depletion of B cell CD19, while
producing less than 50% depletion of normal B cells. Subsequently,
a subcutaneous dose of 400 mg epratuzumab is administered to a new
group of patients with moderately active SLE.
[0253] Total BILAG scores decrease by at least 50% in all patients,
with 92% having decreases continuing to at least 18 weeks. Almost
all patients (93%) experience improvement in at least one BILAG B-
or C-level disease activity at 6, 10 and 18 weeks. Additionally, 3
patients with multiple BILAG B involvement at baseline have
completely resolved all B-level disease activities by 18 weeks.
Epratuzumab is well tolerated, with no evidence of immunogenicity
or significant changes in T cells, immunoglobulins or autoantibody
levels. B-cell levels decrease by an average of 35% at 18 weeks and
remain depressed for 6 months post-treatment.
[0254] All patents and other references cited in the specification
are indicative of the level of skill of those skilled in the art to
which the invention pertains, and are incorporated herein by
reference, including any Tables and Figures, to the same extent as
if each reference had been incorporated by reference individually.
One skilled in the art would readily appreciate that the present
invention is well adapted to obtain the ends and advantages
mentioned, as well as those inherent therein. The methods,
variances, and compositions described herein as presently
representative of preferred embodiments are exemplary and are not
intended as limitations on the scope of the invention. Changes
therein and other uses will occur to those skilled in the art,
which are encompassed within the invention.
Sequence CWU 1
1
20116PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 1Lys Ser Ser Gln Ser Val Leu Tyr Ser Ala Asn His
Lys Tyr Leu Ala 1 5 10 15 27PRTArtificial SequenceDescription of
Artificial Sequence Synthetic peptide 2Trp Ala Ser Thr Arg Glu Ser
1 5 39PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 3His Gln Tyr Leu Ser Ser Trp Thr Phe 1 5
45PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 4Ser Tyr Trp Leu His 1 5 517PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 5Tyr
Ile Asn Pro Arg Asn Asp Tyr Thr Glu Tyr Asn Gln Asn Phe Lys 1 5 10
15 Asp 67PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 6Arg Asp Ile Thr Thr Phe Tyr 1 5
7330PRTArtificial SequenceDescription of Artificial Sequence
Synthetic polypeptide 7Ala Ser Thr Lys Gly Pro Ser Val Phe Pro Leu
Ala Pro Ser Ser Lys 1 5 10 15 Ser Thr Ser Gly Gly Thr Ala Ala Leu
Gly Cys Leu Val Lys Asp Tyr 20 25 30 Phe Pro Glu Pro Val Thr Val
Ser Trp Asn Ser Gly Ala Leu Thr Ser 35 40 45 Gly Val His Thr Phe
Pro Ala Val Leu Gln Ser Ser Gly Leu Tyr Ser 50 55 60 Leu Ser Ser
Val Val Thr Val Pro Ser Ser Ser Leu Gly Thr Gln Thr 65 70 75 80 Tyr
Ile Cys Asn Val Asn His Lys Pro Ser Asn Thr Lys Val Asp Lys 85 90
95 Arg Val Glu Pro Lys Ser Cys Asp Lys Thr His Thr Cys Pro Pro Cys
100 105 110 Pro Ala Pro Glu Leu Leu Gly Gly Pro Ser Val Phe Leu Phe
Pro Pro 115 120 125 Lys Pro Lys Asp Thr Leu Met Ile Ser Arg Thr Pro
Glu Val Thr Cys 130 135 140 Val Val Val Asp Val Ser His Glu Asp Pro
Glu Val Lys Phe Asn Trp 145 150 155 160 Tyr Val Asp Gly Val Glu Val
His Asn Ala Lys Thr Lys Pro Arg Glu 165 170 175 Glu Gln Tyr Asn Ser
Thr Tyr Arg Val Val Ser Val Leu Thr Val Leu 180 185 190 His Gln Asp
Trp Leu Asn Gly Lys Glu Tyr Lys Cys Lys Val Ser Asn 195 200 205 Lys
Ala Leu Pro Ala Pro Ile Glu Lys Thr Ile Ser Lys Ala Lys Gly 210 215
220 Gln Pro Arg Glu Pro Gln Val Tyr Thr Leu Pro Pro Ser Arg Glu Glu
225 230 235 240 Met Thr Lys Asn Gln Val Ser Leu Thr Cys Leu Val Lys
Gly Phe Tyr 245 250 255 Pro Ser Asp Ile Ala Val Glu Trp Glu Ser Asn
Gly Gln Pro Glu Asn 260 265 270 Asn Tyr Lys Thr Thr Pro Pro Val Leu
Asp Ser Asp Gly Ser Phe Phe 275 280 285 Leu Tyr Ser Lys Leu Thr Val
Asp Lys Ser Arg Trp Gln Gln Gly Asn 290 295 300 Val Phe Ser Cys Ser
Val Met His Glu Ala Leu His Asn His Tyr Thr 305 310 315 320 Gln Lys
Ser Leu Ser Leu Ser Pro Gly Lys 325 330 8330PRTArtificial
SequenceDescription of Artificial Sequence Synthetic polypeptide
8Ala Ser Thr Lys Gly Pro Ser Val Phe Pro Leu Ala Pro Ser Ser Lys 1
5 10 15 Ser Thr Ser Gly Gly Thr Ala Ala Leu Gly Cys Leu Val Lys Asp
Tyr 20 25 30 Phe Pro Glu Pro Val Thr Val Ser Trp Asn Ser Gly Ala
Leu Thr Ser 35 40 45 Gly Val His Thr Phe Pro Ala Val Leu Gln Ser
Ser Gly Leu Tyr Ser 50 55 60 Leu Ser Ser Val Val Thr Val Pro Ser
Ser Ser Leu Gly Thr Gln Thr 65 70 75 80 Tyr Ile Cys Asn Val Asn His
Lys Pro Ser Asn Thr Lys Val Asp Lys 85 90 95 Lys Ala Glu Pro Lys
Ser Cys Asp Lys Thr His Thr Cys Pro Pro Cys 100 105 110 Pro Ala Pro
Glu Leu Leu Gly Gly Pro Ser Val Phe Leu Phe Pro Pro 115 120 125 Lys
Pro Lys Asp Thr Leu Met Ile Ser Arg Thr Pro Glu Val Thr Cys 130 135
140 Val Val Val Asp Val Ser His Glu Asp Pro Glu Val Lys Phe Asn Trp
145 150 155 160 Tyr Val Asp Gly Val Glu Val His Asn Ala Lys Thr Lys
Pro Arg Glu 165 170 175 Glu Gln Tyr Asn Ser Thr Tyr Arg Val Val Ser
Val Leu Thr Val Leu 180 185 190 His Gln Asp Trp Leu Asn Gly Lys Glu
Tyr Lys Cys Lys Val Ser Asn 195 200 205 Lys Ala Leu Pro Ala Pro Ile
Glu Lys Thr Ile Ser Lys Ala Lys Gly 210 215 220 Gln Pro Arg Glu Pro
Gln Val Tyr Thr Leu Pro Pro Ser Arg Asp Glu 225 230 235 240 Leu Thr
Lys Asn Gln Val Ser Leu Thr Cys Leu Val Lys Gly Phe Tyr 245 250 255
Pro Ser Asp Ile Ala Val Glu Trp Glu Ser Asn Gly Gln Pro Glu Asn 260
265 270 Asn Tyr Lys Thr Thr Pro Pro Val Leu Asp Ser Asp Gly Ser Phe
Phe 275 280 285 Leu Tyr Ser Lys Leu Thr Val Asp Lys Ser Arg Trp Gln
Gln Gly Asn 290 295 300 Val Phe Ser Cys Ser Val Met His Glu Ala Leu
His Asn His Tyr Thr 305 310 315 320 Gln Lys Ser Leu Ser Leu Ser Pro
Gly Lys 325 330 944PRTArtificial SequenceDescription of Artificial
Sequence Synthetic polypeptide 9Ser His Ile Gln Ile Pro Pro Gly Leu
Thr Glu Leu Leu Gln Gly Tyr 1 5 10 15 Thr Val Glu Val Leu Arg Gln
Gln Pro Pro Asp Leu Val Glu Phe Ala 20 25 30 Val Glu Tyr Phe Thr
Arg Leu Arg Glu Ala Arg Ala 35 40 1045PRTArtificial
SequenceDescription of Artificial Sequence Synthetic polypeptide
10Cys Gly His Ile Gln Ile Pro Pro Gly Leu Thr Glu Leu Leu Gln Gly 1
5 10 15 Tyr Thr Val Glu Val Leu Arg Gln Gln Pro Pro Asp Leu Val Glu
Phe 20 25 30 Ala Val Glu Tyr Phe Thr Arg Leu Arg Glu Ala Arg Ala 35
40 45 1117PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 11Gln Ile Glu Tyr Leu Ala Lys Gln Ile Val Asp Asn
Ala Ile Gln Gln 1 5 10 15 Ala 1221PRTArtificial SequenceDescription
of Artificial Sequence Synthetic peptide 12Cys Gly Gln Ile Glu Tyr
Leu Ala Lys Gln Ile Val Asp Asn Ala Ile 1 5 10 15 Gln Gln Ala Gly
Cys 20 1350PRTArtificial SequenceDescription of Artificial Sequence
Synthetic polypeptide 13Ser Leu Arg Glu Cys Glu Leu Tyr Val Gln Lys
His Asn Ile Gln Ala 1 5 10 15 Leu Leu Lys Asp Ser Ile Val Gln Leu
Cys Thr Ala Arg Pro Glu Arg 20 25 30 Pro Met Ala Phe Leu Arg Glu
Tyr Phe Glu Arg Leu Glu Lys Glu Glu 35 40 45 Ala Lys 50
1455PRTArtificial SequenceDescription of Artificial Sequence
Synthetic polypeptide 14Met Ser Cys Gly Gly Ser Leu Arg Glu Cys Glu
Leu Tyr Val Gln Lys 1 5 10 15 His Asn Ile Gln Ala Leu Leu Lys Asp
Ser Ile Val Gln Leu Cys Thr 20 25 30 Ala Arg Pro Glu Arg Pro Met
Ala Phe Leu Arg Glu Tyr Phe Glu Arg 35 40 45 Leu Glu Lys Glu Glu
Ala Lys 50 55 1523PRTArtificial SequenceDescription of Artificial
Sequence Synthetic peptide 15Cys Gly Phe Glu Glu Leu Ala Trp Lys
Ile Ala Lys Met Ile Trp Ser 1 5 10 15 Asp Val Phe Gln Gln Gly Cys
20 1651PRTArtificial SequenceDescription of Artificial Sequence
Synthetic polypeptide 16Ser Leu Arg Glu Cys Glu Leu Tyr Val Gln Lys
His Asn Ile Gln Ala 1 5 10 15 Leu Leu Lys Asp Val Ser Ile Val Gln
Leu Cys Thr Ala Arg Pro Glu 20 25 30 Arg Pro Met Ala Phe Leu Arg
Glu Tyr Phe Glu Lys Leu Glu Lys Glu 35 40 45 Glu Ala Lys 50
1754PRTArtificial SequenceDescription of Artificial Sequence
Synthetic polypeptide 17Ser Leu Lys Gly Cys Glu Leu Tyr Val Gln Leu
His Gly Ile Gln Gln 1 5 10 15 Val Leu Lys Asp Cys Ile Val His Leu
Cys Ile Ser Lys Pro Glu Arg 20 25 30 Pro Met Lys Phe Leu Arg Glu
His Phe Glu Lys Leu Glu Lys Glu Glu 35 40 45 Asn Arg Gln Ile Leu
Ala 50 1844PRTArtificial SequenceDescription of Artificial Sequence
Synthetic polypeptide 18Ser His Ile Gln Ile Pro Pro Gly Leu Thr Glu
Leu Leu Gln Gly Tyr 1 5 10 15 Thr Val Glu Val Gly Gln Gln Pro Pro
Asp Leu Val Asp Phe Ala Val 20 25 30 Glu Tyr Phe Thr Arg Leu Arg
Glu Ala Arg Arg Gln 35 40 1944PRTArtificial SequenceDescription of
Artificial Sequence Synthetic polypeptide 19Ser Ile Glu Ile Pro Ala
Gly Leu Thr Glu Leu Leu Gln Gly Phe Thr 1 5 10 15 Val Glu Val Leu
Arg His Gln Pro Ala Asp Leu Leu Glu Phe Ala Leu 20 25 30 Gln His
Phe Thr Arg Leu Gln Gln Glu Asn Glu Arg 35 40 204PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptideN-term
DOTAMOD_RES(2)..(2)Lys(HSG)MOD_RES(4)..(4)Lys(HSG)C-term NH2 20Phe
Lys Tyr Lys 1
* * * * *