U.S. patent application number 10/527346 was filed with the patent office on 2006-10-19 for human cd3-specific antibody with immunosuppressive properties.
Invention is credited to Sergey Kipriyanov, Fabrice Le Gall, Melvin Little, Uwe Reusch.
Application Number | 20060233787 10/527346 |
Document ID | / |
Family ID | 31896847 |
Filed Date | 2006-10-19 |
United States Patent
Application |
20060233787 |
Kind Code |
A1 |
Le Gall; Fabrice ; et
al. |
October 19, 2006 |
Human cd3-specific antibody with immunosuppressive properties
Abstract
Described are mono- and multivalent scFv-antibodies comprising
the binding sites specific for human T cell marker CD3. These
antibodies are strongly immunosuppressive and do not cause a
significant release of cytokines. Furthermore, polynucleotides
encoding said antibodies are described as well as vectors
comprising said polynucleotides, host cells transformed therewith
and their use in the production of said antibodies. Pharmaceutical
compositions containing any of the above mentioned polynucleotides,
antibodies or vectors are useful for immunotherapy, preferably
against acute transplant rejections.
Inventors: |
Le Gall; Fabrice;
(Edingen-Neckarhausen, DE) ; Kipriyanov; Sergey;
(Heidelberg, DE) ; Little; Melvin; (Nickargemund,
DE) ; Reusch; Uwe; (Maikammer, DE) |
Correspondence
Address: |
HOWREY LLP
C/O IP DOCKETING DEPARTMENT
2941 FAIRVIEW PARK DRIVE, SUITE 200
FALLS CHURCH
VA
22042-2924
US
|
Family ID: |
31896847 |
Appl. No.: |
10/527346 |
Filed: |
September 10, 2003 |
PCT Filed: |
September 10, 2003 |
PCT NO: |
PCT/EP03/10064 |
371 Date: |
September 23, 2005 |
Current U.S.
Class: |
424/131.1 ;
435/320.1; 435/327; 435/69.1; 514/44R; 530/387.2; 536/23.53 |
Current CPC
Class: |
A61K 2039/505 20130101;
C07K 16/2809 20130101; C07K 2317/626 20130101; C07K 2319/00
20130101; C07K 2317/73 20130101; A61P 37/06 20180101; C07K 2317/34
20130101; C07K 2317/622 20130101; A61K 39/3955 20130101 |
Class at
Publication: |
424/131.1 ;
530/387.2; 435/069.1; 435/327; 435/320.1; 536/023.53; 514/044 |
International
Class: |
A61K 48/00 20060101
A61K048/00; C07K 16/28 20060101 C07K016/28; C07K 16/42 20060101
C07K016/42; C07H 21/04 20060101 C07H021/04; A61K 39/395 20060101
A61K039/395; C12P 21/06 20060101 C12P021/06; C12N 5/06 20060101
C12N005/06 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 10, 2002 |
EP |
02020236.2 |
Claims
1. A bivalent or multivalent antibody characterized by the
following features: (a) it is capable of supressing an immune
reaction; (b) it is devoid of constant antibody regions; and (c) it
binds an epitope on the CD3 complex of the T-cell receptor.
2. The antibody of claim 1 that is a diabody.
3. The antibody of claim 1 that comprises two scFv antibodies
linked by a peptide linker.
4. The antibody of claim 1 that is a single chain diabody.
5. The antibody according to claim 1, wherein variable V.sub.H and
V.sub.L domains are connected via the peptide linker SAKTTP or
SAKTTPKLGG.
6. The antibody according to claim 1, wherein its variable domains
correspond to the variable domains of an antibody produced by the
hybridoma of ATCC deposit number CRL 8001.
7. The antibody according to claim 6, wherein a cysteine at
position H100A has been exchanged for another amino acid.
8. The antibody according to claim 7, wherein the cysteine has been
exchanged for a serine.
9. A polynucleotide, which encodes an antibody according to claim
1.
10. An expression vector comprising the polynucleotide of claim
9.
11. The expression vector of claim 10, which is
pSKK3-scFv.sub.--6-anti-CD3 (DSM 15137).
12. A host cell containing the expression vector of claim 10 or
11.
13. A pharmaceutical composition comprising the antibody of claim
1, the polynucleotide of claim 9, or the expression vector of claim
10.
14. A method for immunotherapy comprising the step of administering
to a subject the pharmaceutical composition according to claim
13.
15. A method for immunotherapy comprising the step of administering
to a subject a pharmaceutical composition comprising the antibody
of claim 1.
16. The method according to claim 14 , wherein said immunotherapy
is a therapy against acute transplant rejections.
17. A method for gene therapy comprising the step of administering
to a subject a pharmaceutical composition comprising the
polynucleotide of claim 9 or the expression vector of claim 10.
Description
[0001] The present invention relates to mono- and multivalent
scFv-antibodies comprising the binding sites specific for the human
T cell marker CD3. The antibodies of the invention are strongly
immunosuppressive and do not cause a significant release of
cytokines. The present invention also relates to polynucleotides
encoding said antibodies as well as vectors comprising said
polynucleotides, host cells transformed therewith and their use in
the production of said antibodies. Finally, the present invention
relates to compositions, preferably pharmaceutical compositions,
comprising any of the above mentioned polynucleotides, antibodies
or vectors. The pharmaceutical compositions are useful for
immunotherapy, preferably against acute transplant rejections.
[0002] OKT3, a murine IgG2a mAb directed against the
.epsilon.-chain of the CD3 complex on human T lymphocytes (Salmeron
et al., J. Immunol. 147 (1991), 3047-3052) and produced by a
hybridoma with the ATCC deposit number of CRL 8001 is used to
prevent tissue rejection after renal and hepatic transplantation,
and provides an alternative treatment for transplant rejections
that are unresponsive to corticosteroids. In vivo, administration
of OKT3 induces a dramatic decrease in the number of circulating
CD3.sup.+cells as it down-modulates the T-cell receptor (TCR).
However, adverse effects can occur during the first days of
treatment. Chills and fever often follow the administration of OKT3
and patients occasionally suffer from nausea, vomiting, diarrhea,
dyspnea, wheezing, and sterile meningitis. Many of these side
effects have been attributed to the release of cytokines,
especially from T cells. After a more prolonged period of use, many
patients develop a human anti-mouse antibody (HAMA) response.
[0003] Binding of OKT3 alone is insufficient to trigger T cells.
Proliferation of T cells which induces the release of cytokines
like IL-2, IL-6, TNF-.alpha.and IFN-.gamma. results from
cross-linking of T cells and FcR-bearing cells. Human IgG Fc
receptors (Fc.gamma.RI, Fc.gamma.RII, Fc.gamma.RIII) are
distributed on human monocytes/macrophages, B lymphocytes, NK cells
and granulocytes. They all bind to the C.sub.H2 region of both
mouse and human IgG, differing in their affinity. The
immunogenicity of such anti-CD3 Ab has been reduced by using
chimeric antibodies made from the variable domains of a mouse mAb
and the constant regions of a human Ab. To reduce binding to Fc
receptors, Fc domains from particular classes of human IgG have
been employed or mutations have been introduced into the Fc domain
in the parts that bind to the Fc receptors. However, interactions
of the Fc domains cannot be completely abrogated and the efficacy
of the immunosuppressive activity was not increased.
[0004] Thus, the technical problem underlying the present invention
was to provide means more suitable for preventing allograft
rejection that overcome the disadvantages of the means of the prior
art.
[0005] The solution of the said technical problem is achieved by
providing the embodiments characterized in the claims. Antibodies
have been constructed that are more efficient in suppressing T cell
activation and proliferation by down-regulating the CD3 molecule
but that do not cause a large release of cytokines, thus avoiding
many of the unpleasant side-effects. These antibodies only comprise
the variable immunoglobulin domains, so called F.sub.v modules by
means of which undesired immune responses can be avoided. The
F.sub.v module is formed by association of the immunoglobulin heavy
and light chain variable domains, V.sub.H and V.sub.L,
respectively. Preferred embodiments of these antibodies are based
only on the variable domains of the OKT3 antibody, but contain a
serine instead of a cysteine at position H100A of the heavy chain
(according to the Kabat numbering system). This mutation has
previously been shown to improve the stability of the single chain
Fv molecule (Kipriyanov et al., Protein Engineering 10 (1997),
445-453). Surprisingly, such antibodies, and in particular a
bivalent antibody in a so-called diabody format, had a much greater
immunosuppressive effect as measured by CD3 downregulation and
inhibition of T cell proliferation in a mixed lymphocyte reaction
(MLR) than the original parental OKT3 antibody and, in contrast to
the parental OKT3, caused no significant release of the cytokines
IFN-.alpha. and IL-2.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1: Schematic representation of mono- and multivalent
single chain Fv-antibody constructs
[0007] Diabody: non-covalent scFv dimer; scDb: single chain
diabody; scFv: single chain Fv fragment; (scFv).sub.2: scFv-scFv
dimer. The antibody V.sub.H and V.sub.L domains are shown as black
and gray ovals, respectively.
[0008] FIG. 2: Expression cassettes for anti-CD3 scFv
constructs
[0009] His.sub.6: six C-terminal histidine residues; L: short
peptide linker (the amino acid sequence is shown in bold)
connecting the V.sub.H and V.sub.L domains; leader, bacterial
leader sequence (e.g. PelB leader) for secretion of recombinant
product into periplasm; rbs, ribosome binding site; Stop: stop
codon (TAA); V.sub.H and V.sub.L: variable regions of the heavy and
light chains specific to human CD3. Four C-terminal amino acids of
V.sub.H domain and four N-terminal amino acids of the V.sub.L
domain are underlined.
[0010] FIG. 3: Diagram of the expression plasmid
pSKK3-scFv6.sub.--OKT3
[0011] bla: gene of beta-lactamase responsible for ampicillin
resistance; bp: base pairs; CDR-H1, CDR-H2 and CDR-H3: sequence
encoding the complementarity determining regions (CDR) 1-3 of the
heavy chain; CDR-L1, CDR-L1, CDR-L2 and CDR-L3: sequence encoding
the complementarity determining regions (CDR) 1-3 of the light
chain; CH1-L6 linker: sequence which encodes the 6 amino acid
peptide Ser-Ala-Lys-Thr-Thr-Pro connecting the V.sub.H and V.sub.L
domains; His6 tag: sequence encoding six C-terminal histidine
residues; hok-sok: plasmid stabilizing DNA locus; lacI: gene
encoding lac-repressor; lac P/O: wild-type lac-operon
promoter/operator; M13ori: intergenic region of bacteriophage M13;
pBR322ori: origin of the DNA replication; PelB leader: signal
peptide sequence of the bacterial pectate lyase; rbs1: ribosome
binding site derived from E. coli lacZ gene (lacZ); rbs2 and rbs3:
ribosome binding site derived from the strongly expressed gene 10
of bacteriophage T7 (T7g10); skp gene: gene encoding bacterial
periplasmic factor Skp/OmpH; tHP: strong transcriptional
terminator; tLPP: lipoprotein terminator of transcription; V.sub.H
and V.sub.L: sequence coding for the variable region of the
immunoglobulin heavy and light chain, respectively. Unique
restriction sites are indicated.
[0012] FIG. 4: Analysis of purified anti-CD3 scFv antibodies by 12%
sodium dodecyl sulfate-polyacrylamide gel electrophoresis
(SDS-PAGE) under reducing conditions
[0013] Lane 1: Mr markers (kDa, M.sub.r in thousands); Lane 2:
anti-CD3 scFv.sub.10; Lane 3: anti-CD3 scFv.sub.6. The gel was
stained with Coomassie Blue.
[0014] FIG. 5: Analysis of purified anti-CD3 scFv antibodies by
size exclusion chromatography on a calibrated Superdex 200
column
[0015] The elution positions of molecular mass standards are
indicated.
[0016] FIG. 6: Lineweaver-Burk analysis of fluorescence dependence
on antibody concentration as determined by flow cytometry Binding
of mAb OKT3 (circles), scFv.sub.6 (triangles) and scFv.sub.10
(squares) to CD3.sup.+Jurkat cells was measured.
[0017] FIG. 7: Retention of anti-CD3 antibodies on the surface of
CD3.sup.+Jurkat cells at 37.degree. C.
[0018] Cell-surface retention of mAb OKT3 (circles), scFv.sub.6
(triangles) and scFv.sub.10 (squares) on CD3.sup.+Jurkat cells was
measured. Values are expressed as a percentage of initial mean
fluorescence intensity.
[0019] FIG. 8: Proliferation of peripheral blood mononuclear cells
(PBMC) after 24 h incubation in presence of mAb OKT3 and anti-CD3
scFv-antibodies at concentrations of 0.01-10 .mu.g/ml
[0020] PBMCs from healthy donor A or donor B alone and mixed
lymphocyte culture of PBMCs from donor A plus B were seeded in
microtiter plates at density of 2.times.10.sup.5 cells/well either
without antibodies or in presence of serial dilutions of mAb OKT3,
anti-CD3 scFv.sub.6 and anti-CD3 scFv.sub.10 . After 24 h
incubation, the cells were pulsed with 10 .mu.M BrdU for 18 h.
Incorporation of BrdU was determined by BrdU-ELISA. The means and
SDs of triplicates are shown.
[0021] FIG. 9: Proliferation of PBMC after 72 h incubation in
presence of mAb OKT3 and anti-CD3 scFv-antibodies at concentrations
of 0.01-10 .mu.g/ml
[0022] PBMCs from healthy donor A or donor B alone and mixed
lymphocyte culture of PBMCs from donor A plus B were seeded in
microtiter plates at density of 2.times.10.sup.5 cells/well either
without antibodies or in presence of serial dilutions of mAb OKT3,
anti-CD3 scFv.sub.6 and anti-CD3 scFv.sub.10. After 72 h
incubation, the cells were pulsed with 10 .mu.M BrdU for 18 h.
Incorporation of BrdU was determined by BrdU-ELISA. The means and
SDs of triplicates are shown.
[0023] FIG. 10: Release of IL-2 by PBMCs after 24 h incubation in
presence of mAb OKT3 and anti-CD3 scFv-antibodies at concentrations
of 0.01-10 .mu.g/ml
[0024] PBMCs from healthy donor A or donor B alone and mixed
lymphocyte culture of PBMCs from donor A plus B were seeded in
24-well plates at a density of 2.times.10.sup.6 cells/well either
without antibodies or in presence of serial dilutions of mAb OKT3,
anti-CD3 scFv.sub.6 and anti-CD3 scFv.sub.10. After 24 h
incubation, samples from the culture supernatants were harvested
and the IL-2 concentration was measured by ELISA. The mean values
of duplicates are shown.
[0025] FIG. 11: Release of IFN-.alpha. by PBMCs after 72 h
incubation in presence of mAb OKT3 and anti-CD3 scFv-antibodies at
concentrations of 0.01-10 .mu.g/ml
[0026] PBMCs from healthy donor A or donor B alone and mixed
lymphocyte culture of PBMCs from donor A plus B were seeded in
24-well plates at a density of 2.times.10.sup.6 cells/well either
without antibodies or in presence of serial dilutions of mAb OKT3,
anti-CD3 scFv.sub.6 and anti-CD3 scFv.sub.10. After 72 h
incubation, the samples of culture supernatants were harvested and
the concentration of IFN-.alpha. was measured by ELISA. The mean
values of duplicates are shown.
[0027] FIG. 12: Release of TNF-.alpha. by PBMCs after 36 h
incubation in the presence of mAb OKT3 and anti-CD3 scFv-antibodies
at concentrations of 0.01-0.1 .mu.g/ml
[0028] PBMCs from healthy donor A or donor B alone and mixed
lymphocyte culture of PBMCs from donor A plus B were seeded in
24-well plates at a density of 2.times.10.sup.6 cells/well either
without antibodies or in presence 0.1 .mu.g/ml and 0.01 .mu.g/ml of
mAb OKT3, anti-CD3 scFv.sub.6 and anti-CD3 scFv.sub.10. After 36 h
incubation, samples of the culture supernatants were harvested and
the concentration of TNF-.alpha. was measured by ELISA. The mean
values of duplicates are shown.
[0029] FIG. 13: Induction of the expression of IL-2R.alpha. (CD25)
on T cells after 90 h incubation of PBMC cultures in presence of
mAb OKT3 and anti-CD3 scFv-antibodies at concentrations of 0.01-10
.mu.g/ml
[0030] PBMCs from healthy donor A or donor B alone and mixed
lymphocyte culture of PBMCs from donor A plus B were seeded in
24-well plates at a density of 2.times.10.sup.6 cells/well either
without antibodies or in presence of serial dilutions of mAb OKT3,
anti-CD3 scFv.sub.6 and anti-CD3 scFv.sub.10. After 90 h
incubation, the CD25 expression was detected by flow cytometry
using anti-CD25 mAb B1.49.9. Mean fluorescence intensity values
after subtracting background fluorescence are shown.
[0031] FIG. 14: CD3 modulation and coating by mAb OKT3 and anti-CD3
scFv-antibodies
[0032] PBMCs from healthy donor A or donor B were seeded in 24-well
plates at a density of 2.times.10.sup.6 cells/well either without
antibodies or in presence of serial dilutions of mAb OKT3, anti-CD3
scFv.sub.6 and anti-CD3 scFv.sub.10. After 24 h incubation, the
cells were harvested and stained with FITC-conjugated anti-CD3 mAb
OKT3, PC5-conjugated anti-TCR.alpha./.beta. mAb BMA031. T cells
were counterstained with anti-CD5 mAb and analyzed by flow
cytometry. Data for CD3 modulation represent the percentage of
TCR/CD3 complexes on the surface of treated CD5-positive T cells as
a fraction of TCR/CD3 complexes on the surface of untreated
CD5-positive T cells. CD3 coating is shown as the fraction of
TCR/CD3 complexes which could not be detected by FITC-conjugated
OKT3.
[0033] FIG. 15: (a) DNA sequence of plasmid pSKK3-scFv6 anti-CD3;
(b) amino acid sequence of the V.sub.H and V.sub.L connected by the
peptide linker SAKTTP encoded by the DNA sequence contained in
pSKK3-scFv6 anti-CD3
[0034] Thus, the present invention relates to an antibody
characterized by the following features: [0035] (a) it is capable
of suppressing an immune reaction; [0036] (b) it is devoid of
constant antibody regions; and [0037] (c) it binds an epitope on
the CD3 complex of the T-cell receptor.
[0038] The antibody of the present invention is specific to human
TCR/CD3 complex present on all T cells regardless their MHC
specificity. Such antibody is capable to suppress the activated T
lymphocytes without any significant release of inflammatory
cytokines, thus avoiding many of the unpleasant side-effects. The
release of cytokines, e.g., IL-2, IFN-.gamma. and TNF-.alpha. is
reduced by a factor more than 100 compared to OKT3. This is in
sharp contrast with any known immunosuppressive antibodies.
Although immunosuppression can be achieved by the administering
such traditional antibodies to humans, their efficacy is often
compromised by two factors: the first-dose syndrome resulting from
T-cell activation, and the anti-globulin response (e.g. HAMA
response) resulting from multiple injections of foreign proteins of
non-human origin. The symptoms of antibody toxicity include fever,
chills, diarrhea, and vomiting and in severe cases have resulted in
death. The syndrome is caused by the release of inflammatory
cytokines as result of transient T cell activation. Such activation
depends on the interaction of the Fc portion of the antibody and Fc
receptors (FcR) on accessory cells to cross-link the CD3 complexes
on T cells. The Fc portion of mabs of murine origin is also the
main reason of anti-globulin response. The antibody of the present
invention is devoid of the immunoglobulin constant domains and,
therefore, is not able to interact with FcRs and is also much less
immunogenic.
[0039] The antibodies of the present invention can be prepared by
methods known to the person skilled in the art, e.g. by the
following methods:
[0040] (a) Construction of single chain Fv-antibodies by combining
the genes encoding at least two immunoglobulin variable V.sub.H and
V.sub.L domains, either separated by peptide linkers or by no
linkers, into a single genetic construct and expressing it in
bacteria or other appropriate expression system.
[0041] (b) Non-covalent dimerization or multimerization of single
chain Fv-antibodies comprising at least two V.sub.H and V.sub.L
specific to human CD3 either separated by peptide linkers or by no
linkers, in an orientation preventing their intramolecular
pairing.
[0042] The term "capable of suppressing an immune reaction" means
that the antibody is able, on the one hand, to prevent activation
of T lymphocytes by foreign alloantigen and, on the other hand, to
selectively deplete already activated T cells.
[0043] The antibody of the present invention may be a monovalent,
bivalent or multivalent antibody.
[0044] In a preferred embodiment, the antibody of the present
invention is a non-covalent dimer of a single-chain Fv-antibody
(scFv) ("diabody" ; see FIG. 1) comprising CD3-specific V.sub.H and
V.sub.L domains, either separated by peptide linkers or by no
linkers.
[0045] In a further preferred embodiment, the antibody of the
present invention comprises two single-chain Fv-antibodies (scFv)
(see FIG. 1) comprising CD3-specific V.sub.H and V.sub.L
domains.
[0046] In a further preferred embodiment, the antibody of the
present invention is a single chain diabody (see FIG. 1) comprising
CD3-specific V.sub.H and V.sub.L domains.
[0047] The term "Fv-antibody" as used herein relates to an antibody
containing variable domains but not constant domains. The term
"peptide linker" as used herein relates to any peptide capable of
connecting two variable domains with its length depending on the
kinds of variable domains to be connected. The peptide linker might
contain any amino acid residue, although the amino acid
combinations SAKTTP or SAKTTPKLGG are preferred. The peptide linker
connecting single scFv of (scFv).sub.2 and single chain diabodies
(scDb) might contain any amino acid residue, although one-to-three
repeats of amino acid combination GGGGS are preferred for
(scFv).sub.2 and three-to-four repeats of GGGGS are preferred for
scDb.
[0048] In a more preferred embodiment, the antibody of the present
invention contains variable domains substantially corresponding to
the variable domains of the antibody produced by the hybridoma of
ATCC deposit number CRL 8001.
[0049] In an even more preferred embodiment, the antibody of the
present invention is characterized in that a cysteine at position
H100A (Kabat numbering system) has been replaced by another amino
acid, preferably by a serine.
[0050] The present invention also relates to a polynucleotide
encoding an antibody of the present invention and vectors,
preferably expression vectors containing said polynucleotides. The
recombinant vectors can be constructed according to methods well
known to the person skilled in the art; see, e.g., Sambrook,
Molecular Cloning A Laboratory Manual, Cold Spring Harbor
Laboratory (1989) N.Y.
[0051] A variety of expression vector/host systems may be utilized
to contain and express sequences encoding the antibody of the
present invention. These include, but are not limited to,
microorganisms such as bacteria transformed with recombinant
bacteriophage, plasmid, or cosmid DNA expression vectors; yeast
transformed with yeast expression vectors; insect cell systems
infected with virus expression vectors (e.g., baculovirus); plant
cell systems transformed with virus expression vectors (e.g.,
cauliflower mosaic virus, CaMV; tobacco mosaic virus, TMV) or with
bacterial expression vectors (e.g., Ti or pBR322 plasmids); or
animal cell systems.
[0052] The "control elements" or "regulatory sequences" are those
non-translated regions of the vector-enhancers, promoters, 5'- and
b 3'-untranslated regions which interact with host cellular
proteins to carry out transcription and translation. Such elements
may vary in their strength and specificity. Depending on the vector
system and host utilized, any number of suitable transcription and
translation elements, including constitutive and inducible
promoters, may be used. For example, when cloning in bacterial
systems, inducible promoters such as the hybrid lacZ promoter of
the Bluescript.RTM. phagemid (Stratagene, Lajolla, Calif.) or
pSportl.TM. plasmid (Gibco BRL) and the like may be used. The
baculovirus polyhedrin promoter may be used in insect cells.
Promoters or enhancers derived from the genomes of plant cells
(e.g., heat shock, RUBISCO; and storage protein genes) or from
plant viruses (e.g., viral promoters or leader sequences) may be
cloned into the vector. In mammalian cell systems, promoters from
mammalian genes or from mammalian viruses are preferable. If it is
necessary to generate a cell line that contains multiple copies of
the sequence encoding the multivalent multimeric antibody, vectors
based on SV40 or EBV may be used with an appropriate selectable
marker.
[0053] In bacterial systems, a number of expression vectors may be
selected depending upon the use intended for the antibody of the
present invention. Vectors suitable for use in the present
invention include, but are not limited to the pSKK expression
vector for expression in bacteria.
[0054] In the yeast, Saccharomyces cerevisiae, a number of vectors
containing constitutive or inducible promoters such as alpha
factor, alcohol oxidase, and PGH may be used; for reviews, see
Grant et al. (1987) Methods Enzymol. 153:516-544.
[0055] In cases where plant expression vectors are used, the
expression of sequences encoding the antibody of the present
invnetion may be driven by any of a number of promoters. For
example, viral promoters such as the 35S and 19S promoters of CaMV
may be used alone or in combination with the omega leader sequence
from TMV (Takamatsu, N. (1987) EMBO J. 6:307-311). Alternatively,
plant promoters such as the small subunit of RUBISCO or heat shock
promoters may be used (Coruzzi, G. et al. (1984) EMBO J.
3:1671-1680; Broglie, R. et al. (1984) Science 224:838-843; and
Winter, J. et al. (1991) Results Probl. Cell Differ. 17:85-105).
These constructs can be introduced into plant cells by direct DNA
transformation or pathogen-mediated transfection. Such techniques
are described in a number of generally available reviews (see, for
example, Hobbs, S. and Murry, L. E. in McGraw Hill Yearbook of
Science and Technology (1992) McGraw Hill, New York, N.Y.; pp.
191-196.
[0056] An insect system may also be used to express the antibodies
of the present invention. For example, in one such system,
Autographa californica nuclear polyhedrosis virus (AcNPV) is used
as a vector to express foreign genes in Spodoptera frugiperda cells
or in Trichoplusia larvae. The sequences encoding said antibodies
may be cloned into a non-essential region of the virus, such as the
polyhedrin gene, and placed under control of the polyhedrin
promoter. Successful insertion of the gene encoding said antibody
will render the polyhedrin gene inactive and produce recombinant
virus lacking coat protein. The recombinant viruses may then be
used to infect, for example, S. frugiperda cells or Trichoplusia
larvae in which APOP may be expressed (Engelhard, E. K. et al.
(1994) Proc. Nat. Acad. Sci. 91:3224-3227).
[0057] In mammalian host cells, a number of viral-based expression
systems may be utilized. In cases where an adenovirus is used as an
expression vector, sequences encoding an antibody of the present
invention may be ligated into an adenovirus
transcription/translation complex consisting of the late promoter
and tripartite leader sequence. Insertion in a non-essential E1 or
E3 region of the viral genome may be used to obtain a viable virus
which is capable of expressing the antibody in infected host cells
(Logan, J. and Shenk, T. (1984) Proc. Natl. Acad. Sci.
81:3655-3659). In addition, transcription enhancers, such as the
Rous sarcoma virus (RSV) enhancer, may be used to increase
expression in mammalian host cells.
[0058] Human artificial chromosomes (HACs) may also be employed to
deliver larger fragments of DNA than can be contained and expressed
in a plasmid. HACs of 6 to 10M are constructed and delivered via
conventional delivery methods (liposomes, polycationic amino
polymers, or vesicles) for therapeutic purposes.
[0059] Specific initiation signals may also be used to achieve more
efficient translation of sequences encoding the antibody of the
present invention. Such signals include the ATG initiation codon
and adjacent sequences. In cases where sequences encoding the
antibody, its initiation codon, and upstream sequences are inserted
into the appropriate expression vector, no additional
transcriptional or translational control signals may be needed.
However, in case where only coding sequence is inserted, exogenous
translational control signals including the ATG initiation codon
should be provided. Furthermore, the initiation codon should be in
the correct reading frame to ensure translation of the entire
insert. Exogenous translational elements and initiation codons may
be of various origins, both natural and synthetic. The efficiency
of expression may be enhanced by the inclusion of enhancers which
are appropriate for the particular cell system which is used, such
as those described in the literature (Scharf, D. et al. (1994)
Results Probl. Cell Differ. 20:125-162).
[0060] In addition, a host cell strain may be chosen for its
ability to modulate the expression of the inserted sequences or to
process the expressed antibody chains in the desired fashion.
Post-translational processing which cleaves a "prepro" form of the
protein may also be used to facilitate correct insertion, folding
and/or function. Different host cells which have specific cellular
machinery and characteristic mechanisms for post-translational
activities (e.g., CHO, HeLa, MDCK, HEK293, and W138), are available
from the American Type Culture Collection (ATCC; Bethesda, Md.) and
may be chosen to ensure the correct modification and processing of
the foreign antibody chains.
[0061] For long-term, high-yield production of recombinant
antibodies, stable expression is preferred. For example, cell lines
which stably express the antibody may be transformed using
expression vectors which may contain viral origins of replication
and/or endogenous expression elements and a selectable marker gene
on the same or on a separate vector. Following the introduction of
the vector, cells may be allowed to grow for 1-2 days in an
enriched media before they are switched to selective media. The
purpose of the selectable marker is to confer resistance to
selection, and its presence allows growth and recovery of cells
which successfully express the introduced sequences. Resistant
clones of stably transformed cells may be proliferated using tissue
culture techniques appropriate to the cell type.
[0062] Any number of selection systems may be used to recover
transformed cell lines. These include, but are not limited to, the
herpes simplex virus thymidine kinase (Wigler, M. et al. (1977)
Cell 11:223-32) and adenine phosphoribosyltransferase (Lowy, I. et
al. (1980) Cell 22:817-23) genes which can be employed in tk.sup.-
or aprt.sup.- cells, respectively. Also, antimetabolite, antibiotic
or herbicide resistance can be used as the basis for selection; for
example, dhfr which confers resistance to methotrexate (Wigler, M.
et al. (1980) Proc. Natl. Acad. Sci. 77:3567-70); npt, which
confers resistance to the aminoglycosides neomycin and G-418
(Colbere-Garapin, F. et al (1981) J. Mol. Biol. 150:1-14) and als
or pat, which confer resistance to chlorsulfuron and
phosphinotricin acetyltransferase, respectively (Murry, supra).
Additional selectable genes have been described, for example, trpB,
which allows cells to utilize indole in place of tryptophan, or
hisD, which allows cells to utilize histinol in place of histidine
(Hartman, S. C. and R. C. Mulligan (1988) Proc. Natl. Acad. Sci.
85:8047-51). Recently, the use of visible markers has gained
popularity with such markers as anthocyanins, beta-glucuronidase
and its substrate GUS, and luciferase and its substrate luciferin,
being widely used not only to identify transformants, but also to
quantify the amount of transient or stable protein expression
attributable to a specific vector system (Rhodes, C. A. et al.
(1995) Methods Mol. Biol. 55:121-131).
[0063] A particular preferred expression vector is
pSKK3-scFv6.sub.--anti-CD3 deposited with the DSMZ (Deutsche
Sammlung fur Mikroorganismen und Zellen) according to the Budapest
Treaty under DSM 15137 on Aug. 16, 2002.
[0064] The present invention also relates to a composition
containing an antibody, polynucleotide or an expression vector of
the present invention. Preferably, said composition is a
pharmaceutical composition preferably combined with a suitable
pharmaceutical carrier. Examples of suitable pharmaceutical
carriers are well known in the art and include phosphate buffered
saline solutions, water, emulsions, such as oil/water emulsions,
various types of wetting agents, sterile solutions etc.. Such
carriers can be formulated by conventional methods and can be
administered to the subject at a suitable dose. Administration of
the suitable compositions may be effected by different ways, e.g.
by intravenous, intraperetoneal, subcutaneous, intramuscular,
topical or intradermal administration. The route of administration,
of course, depends on the kind of therapy and the kind of compound
contained in the pharmaceutical composition. The dosage regimen
will be determined by the attending physician and other clinical
factors. As is well known in the medical arts, dosages for any one
patient depends on many factors, including the patient's size, body
surface area, age, sex, the particular compound to be administered,
time and route of administration, the kind of therapy, general
health and other drugs being administered concurrently.
[0065] A preferred medical use of the compounds of the present
invention described above is immunotherapy, preferably a therapy
against acute transplant rejections and possibly against autoimmune
diseases, such as type I diabetes, multiple sclerosis and
rheumatoid arthritis.
[0066] The examples below explain the invention in more detail.
EXAMPLE 1
Construction of the Plasmids pHOG-scFv10/anti-CD3,
pHOG-scFv6/anti-CD3, pSKK3-scFv10/anti-CD3 and pSKK3-scFv6/anti-CD3
for the expression of anti-CD3 scFv.sub.10 and scFv.sub.6
antibodies in bacteria
[0067] For constructing the genes encoding the anti-CD3 scFv.sub.10
and scFv.sub.6 (FIG. 2), the plasmid pHOG21-dmOKT3 containing the
gene for anti-human CD3 scFv.sub.18 (Kipriyanov et al., 1997,
Protein Engineering 10, 445-453) was used. To facilitate the
cloning procedures, NotI restriction site was introduced into the
plasmid pHOG21-dmOKT3 by PCR amplification of scFv.sub.18 gene
using primers Bi3sk, 5'-CAGCCGGCCATGGCGCAGGTGCAACTGCAGCAG and
Bi9sk, 5'-GAAGATGGATCCAGCGGCCGCAGTATCAGCCCGGTT. The resulting 776
bp PCR fragment was digested with NcoI and NotI and cloned into the
NcoI/NotI-linearized vector pHOG21-CD19 (Kipriyanov et al., 1996,
J. Immunol. Methods 196, 51-62), thus generating the plasmid
pHOG21-dmOKT3+Not. The gene coding for OKT3 V.sub.H domain with a
Cys-Ser substitution at position 100A according to Kabat numbering
scheme (Kipriyanov et al., 1997, Protein Engineering 10, 445-453)
was amplified by PCR with primers DP1,
5'-TCACACAGAATTCTTAGATCTATTAAAGAGGAGAAATTAACC and either DP2,
5'-AGCACACGATATCACCGCCAAGCTTGGGTGTTGTTTTGGC or OKT.sub.--5, 5'-
TATTAAGATATCGGGTGTTGTTTTGGCTGAGGAG, to generate the genes for
V.sub.H followed by linkers of 10 and 6 amino acids, respectively
(FIG. 2). The resulting 507 bp and 494 bp PCR fragments were
digested with NcoI and EcoRV and cloned into NcoI/EcoRV-linearized
plasmid pHOG21-dmOKT3+Not, thus generating the plasmids
pHOG21-scFv10/anti-CD3 and pHOG21-scFv6/anti-CD3, respectively.
[0068] To increase the yield of functional scFv-antibodies in the
bacterial periplasm, an optimized expression vector pSKK3 was
generated (FIG. 3). This vector was constructed on the basis of
plasmid PHKK (Horn et al., 1996, Appl. Microbiol. Biotechnol. 46,
524-532) containing hok/sok plasmid-free cell suicide system
(Thisted et al., 1994, EMBO J. 13, 1960-1968). First, the gene
coding for hybrid scFv VH.sup.3-V.sub.L 19 was amplified by PCR
from the plasmid pHOG3-19 (Kipriyanov et al., 1998, Int. J. Cancer
77, 763-772) using the primers 5-NDE, 5'-
GATATACATATGAAATACCTATTGCCTACGGC, and 3-AFL,
5'-CGAATTCTTAAGTTAGCACAGGCCTCTAGAGACACACAGATCTTTAG. The resulting
921 bp PCR fragment was digested with NdeI and AflII and cloned
into the NdeI/AflII linearized plasmid pHKK generating the vector
pHKK3-19. To delete an extra XbaI site, a fragment of pHKK plasmid
containing 3'-terminal part of the lacI gene (encoding the lac
repressor), the strong transcriptional terminator tHP and wild-type
lac promoter/operator was amplified by PCR using primers 5-NAR,
5'-CACCCTGGCGCCCAATACGCAAACCGCC, and 3-NDE,
5'-GGTATTTCATATGTATATCTCCTTCTTCAGAAATTCGTAATCATGG. The resulting
329 bp DNA fragment was digested with NarI and NdeI and cloned into
NarI/NdeI-linearized plasmid pHKK3-19 generating the vector
pHKK.quadrature.OXba. To introduce a gene encoding the Skp/OmpH
periplasmic factor for higher recombinant antibody production
(Bothmann and Pluckthun, 1998, Nat. Biotechnol. 16, 376-380), the
skp gene was amplified by PCR with primers skp-3,
5'-CGAATTCTTAAGAAGGAGATATACATATGAAAAAGTGGTTATTAGCTGCAGG and skp-4,
5'-CGAATTCTCGAGCATTATTTAACCTGTTTCAGTACGTCGG using as a template the
plasmid pGAH317 (Holck and Kleppe, 1988, Gene 67, 117-124). The
resulting 528 bp PCR fragment was digested with AflII and XhoI and
cloned into the AflII/XhoI digested plasmid pHKK.quadrature.Xba
resulting in the expression plasmid pSKK2. For removing the
sequence encoding potentially immunogenic c-myc epitope, the
NcoI/XbaI-linearized plasmid pSKK2 was used for cloning the
NcoI/XbaI-digested 902 bp PCR fragment encoding the scFv phOx31E
(Marks et al. 1997, BioTechnology 10, 779-783), which was amplified
with primers DP1 and His-Xba,
5'-CAGGCCTCTAGATTAGTGATGGTGATGGTGATGGG. The resulting plasmid pSKK3
was digested with NcoI and NotI and used as a vector for cloning
the genes coding for anti-CD3 scFv.sub.6 and scFv.sub.10 , that
were isolated as 715 bp and 727 bp DNA fragments after digestion of
plasmids pHOG21-scFv6/anti-CD3 and pHOG21-scFv10/anti-CD3,
respectively, with NcoI and NotI.
[0069] The generated plasmids pSKK3-scFv6/anti-CD3 (FIG. 3) and
pSKK3-scFv10/anti-CD3 contain several features that improve plasmid
performance and lead to increased accumulation of functional
bivalent product in the E. coli periplasm under conditions of both
shake-flask cultivation and high cell density fermentation. These
are the hok/sok post-segregation killing system, which prevents
plasmid loss, strong tandem ribosome-binding sites and a gene
encoding the periplasmic factor Skp/OmpH that increases the
functional yield of antibody fragments in bacteria. The expression
cassette is under the transcriptional control of the wt lac
promoter/operator system and includes a short sequence coding for
the N-terminal peptide of .beta.-galactosidase (lacZ') with a first
rbs derived from the E. coli lacZ gene, followed by genes encoding
the scFv-antibody and Skp/OmpH periplasmic factor under the
translational control of strong rbs from gene 10 of phage T7
(T7g10). Besides, the gene of scFv-antibody is followed by a
nucleotide sequence encoding six histidine residues for both
immunodetection and purification of recombinant product by
immobilized metal-affinity chromatography (IMAC).
EXAMPLE 2
Production in Bacteria and Purification of scFv-Antibodies
[0070] The E. coli K12 strain RV308 (.DELTA.lac.chi.74
galISII::OP308strA) (Maurer et al., 1980, J. Mol. Biol. 139,
147-161) (ATCC 31608) was used for functional expression of
scFv-antibodies. The bacteria transformed with the expression
plasmids pSKK3-scFv6/anti-CD3 and pSKK3-scFv10/anti-CD3,
respectively, were grown overnight in 2xYT medium with 100 .mu.g/ml
ampicillin and 100 mM glucose (.sup.2xYTGA) at 26.degree. C. The
overnight cultures were diluted in fresh 2xYTGA medium till optical
density at 600 nm (OD.sub.600) of 0.1 and continued to grow as
flask cultures at 26.degree. C. with vigorous shaking (180-220 rpm)
until OD.sub.600 reached 0.6-0.8. Bacteria were harvested by
centrifugation at 5,000 g for 10 min at 20.degree. C. and
resuspended in the same volume of fresh YTBS medium (2xYT
containing 1 M sorbitol, 2.5 mM glycine betaine and 50 .mu.g/ml
ampicillin). Isopropyl-.beta.-D-thiogalactopyranoside (IPTG) was
added to a final concentration of 0.2 mM and growth was continued
at 21.degree. C. for 14-16 h. Cells were harvested by
centrifugation at 9,000 g for 20 min at 4.degree. C. To isolate
soluble periplasmic proteins, the pelleted bacteria were
resuspended in 5% of the initial volume of ice-cold 200 mM
Tris-HCl, 20% sucrose, 1 mM EDTA, pH 8.0. After 1 h incubation on
ice with occasional stirring, the spheroplasts were centrifuged at
30,000 g for 30 min and 4.degree. C. leaving the soluble
periplasmic extract as the supernatant and spheroplasts plus the
insoluble periplasmic material as the pellet. The periplasmic
extract was thoroughly dialyzed against 50 mM Tris-HCl, 1 M NaCl,
pH 7.0, and used as a starting material for isolating
scFv-antibodies. The recombinant product was concentrated by
ammonium sulfate precipitation (final concentration 70% of
saturation). The protein precipitate was collected by
centrifugation (10,000 g, 4.degree. C., 40 min) and dissolved in
10% of the initial volume of 50 mM Tris-HC1, 1 M NaCl, pH 7.0,
followed by thorough dialysis against the same buffer. Immobilized
metal affinity chromatography (IMAC) was performed at 4.degree. C.
using a 5 ml column of Chelating Sepharose (Amersham Pharmacia,
Freiburg, Germany) charged with Cu.sup.2+and equilibrated with 50
mM Tris-HCl, 1 M NaCl, pH 7.0 (start buffer). The sample was loaded
by passing the sample over the column by gravity flow. The column
was then washed with twenty column volumes of start buffer followed
by start buffer containing 50 mM imidazole until the absorbance
(280 nm) of the effluent was minimal (about thirty column volumes).
Absorbed material was eluted with 50 mM Tris-HCl, 1 M NaCl, 300 mM
imidazole, pH 7.0, as 1 ml fractions. The eluted fractions
containing recombinant protein were identified by reducing 12%
SDS-PAGE followed by Coomassie staining. The positive fractions
were pooled and subjected to buffer exchange for 50 mM
imidazole-HCl.sub.1, 50 mM NaCl (pH 7.0) using pre-packed PD-10
columns (Pharmacia Biotech, Freiburg, Germany). The turbidity of
protein solution was removed by centrifugation (30,000 g, 1 h,
4.degree. C).
[0071] The final purification was achieved by ion-exchange
chromatography on a Mono S HR 5/5 column (Amersham Pharmacia,
Freiburg, Germany) in 50 mM imidazole-HCl, 50 mM NaCl, pH 7.0, with
a linear 0.05-1 M NaCl gradient. The fractions containing
scFv-antibody were concentrated with simultaneous buffer exchange
for PBS containing 50 mM imidazole, pH 7.0 (PBSI buffer), using
Ultrafree-15 centrifugal filter device (Millipore, Eschborn,
Germany). Protein concentrations were determined by the Bradford
dye-binding assay (Bradford, 1976, Anal. Biochem., 72, 248-254)
using the Bio-Rad (Munich, Germany) protein assay kit. SDS-PAGE
analysis demonstrated that anti-CD3 scFv.sub.10 and scFv.sub.6
migrated as single bands with a molecular mass (M.sub.r) around 30
kDa (FIG. 4). Size-exclusion chromatography on a calibrated
Superdex 200 HR 10/30 column (Amersham Pharmacia) demonstrated that
scFv.sub.6 was mainly in a dimeric form with Mr around 60 kDa,
while scFv.sub.10 was pure monomer (FIG. 5).
EXAMPLE 3
Cell Binding Measurements
[0072] The human CD3.sup.+T-cell leukemia cell line Jurkat was used
for flow cytometry experiments. The cells were cultured in RPMI
1640 medium supplemented with 10% heat-inactivated fetal calf serum
(FCS), 2 mM L-glutamine, 100 U/mL penicillin G sodium and 100
.mu.g/ml streptomycin sulfate (all from Invitrogen, Groningen, The
Netherlands) at 37.degree. C. in a humidified atmosphere with 5%
CO.sub.2. 1.times.10.sup.6 cells were incubated with 0.1 ml
phosphate buffered saline (PBS, Invitrogen, Groningen, The
Netherlands) supplemented with 2% heat-inactivated fetal calf serum
(FCS, Invitrogen, Groningen, The Netherlands) and 0.1% sodium azide
(Roth, Karlsruhe, Germany) (referred to as FACS buffer) containing
diluted scFv-antibodies or mAb OKT3 (Orthoclone OKT3, Cilag,
Sulzbach, Germany) for 45 min on ice. After washing with FACS
buffer, the cells were incubated with 0.1 ml of 0.01 mg/ml
anti-(His).sub.6 mouse mAb 13/45/31-2 (Dianova, Hamburg, Germany)
in the same buffer for 45 min on ice. After a second washing cycle,
the cells were incubated with 0.1 ml of 0.015 mg/ml FITC-conjugated
goat anti-mouse IgG (Dianova, Hamburg, Germany) under the same
conditions as before. The cells were then washed again and
resuspended in 0.5 ml of FACS buffer containing 2 .mu.g/ml
propidium iodide (Sigma-Aldrich, Taufkirchen, Germany) to exclude
dead cells. The fluorescence of 1.times.10.sup.4 stained cells was
measured using a Beckman-Coulter Epics XL flow cytometer
(Beckman-Coulter, Krefeld, Germany). Mean fluorescence (F) was
calculated using System-II and Expo32 software (Beckman-Coulter,
Krefeld, Germany) and the background fluorescence was subtracted.
Equilibrium dissociation constants (K.sub.d) were determined by
fitting the experimental values to the Lineweaver-Burk equation:
1/F=1/F.sub.max,+(K.sub.d/F.sub.max)(1/[Ab]) using the software
program PRISM (GraphPad Software, San Diego, Calif.).
[0073] The flow cytometry experiments demonstrated a specific
interaction of scFv-antibodies to Jurkat cells expressing CD3 on
their surface. The fluorescence intensities obtained for scFv.sub.6
were significantly higher than for scFv.sub.10 reflecting the
10-fold difference in affinity values for these two scFv-antibodies
(FIG. 6, Table 1). The deduced affinity value for scFv.sub.6 was
fairly close to that of mAb OKT3 thus confirming the bivalent
binding of scFv6 to the cell surface.
EXAMPLE 4
In Vitro Cell Surface Retention
[0074] To investigate the biological relevance of the differences
between scFv.sub.6, scFv.sub.10 and OKT3 in direct binding
experiments, the in vitro retention of the scFv-antibodies on the
surface of CD3.sup.+Jurkat cells was determined by flow cytometry
(FIG. 7). Cell surface retention assays were performed at
37.degree. C. under conditions preventing internalization of cell
surface antigens, as described (Adams et al., 1998, Cancer Res. 58,
485-490), except that the detection of retained scFv-antibodies was
performed using mouse anti-(His).sub.6 mAb 13/45/31-2 (0.01 mg/ml;
Dianova, Hamburg, Germany) followed by FITC-conjugated goat
anti-mouse IgG (0.015 mg/ml; Dianova, Hamburg, Germany). Kinetic
dissociation constant (k.sub.off) and half-life (t.sub.1/2) values
for dissociation of antibodies were deduced from a one-phase
exponential decay fit of experimental data using the software
program PRISM (GraphPad Software, San Diego, Calif). The monovalent
scFv.sub.10 had a relatively short retention half-life (1.02 min),
while scFv.sub.6 and OKT3 had 1.5-fold and 2.5-fold longer
t.sub.1/2respectively, thus correlating well with their higher
binding affinities deduced from the direct binding experiments
(FIG. 7, Table 1). TABLE-US-00001 TABLE 1 Affinity and kinetics of
anti-CD3 antibodies binding to CD3.sup.+ Jurkat cells Antibody
K.sub.d (nM) k.sub.off (s.sup.-1/10.sup.-3) t.sub.1/2 (min) mAb
OKT3 2.06 4.47 2.59 scFv.sub.6 4.58 7.82 1.48 scFv.sub.10 51.92
11.33 1.02
The dissociation constants (K.sub.d) were deduced from
Lineweaver-Burk plots shown in FIG. 6. The k.sub.off values were
deduced from Jurkat cell surface retention experiments shown in
FIG. 7. The half-life values (t.sub.1/2) for dissociation of
antibody-antigen complexes were deduced from the ratio
ln2/k.sub.off.
EXAMPLE 5
Isolation of Peripheral Blood Mononuclear Cells (PBMCs)
[0075] Human PBMCs were isolated from the heparinized peripheral
blood of healthy volunteers by density gradient centrifugation. The
blood samples were twice diluted with PBS (Invitrogen, Groningen,
The Netherlands), layered on a cushion of Histopaque-1077
(Sigma-Aldrich, Taufkirchen, Germany) and centrifuged at 800 g for
25 min. The PBMCs located in the interface were collected and
washed three times with PBS before use.
EXAMPLE 6
Cell Proliferation Assay
[0076] Isolated PBMCs were resuspended in RPMI 1640 medium
supplemented with 10% heat-inactivated FCS, 2 mM L-glutamine, 100
U/ml penicillin G sodium salt and 0.1 mg/ml streptomycin sulfate
(all from Invitrogen, Groningen, The Netherlands) and placed to
96-well flat-bottom tissue culture plates (Greiner, Frickenhausen,
Germany) at a density of 2.times.10.sup.5 cells per well.
Triplicates of cultures were incubated with serial dilutions of
soluble antibodies at 37.degree. C. in a humidified atmosphere
containing 5% CO.sub.2 for the indicated time followed by 18 h
pulsing with 0.01 mM 5-bromo-2'-deoxyuridine (BrdU). Incorporation
of BrdU was determined by Cell Proliferation ELISA (Roche,
Mannheim, Germany) according to the manufacturers instructions.
[0077] During incubation for 24-36 h, neither scFv.sub.6 nor
scFv.sub.1o induced proliferation of both autologous (donor A alone
and donor B alone, respectively) and mixed lymphocyte cultures
(donor A+B). In contrast, mAb OKT3 demonstrated high mitogenic
activity for all tested 24 h cultures, obviously due to
CD3-crosslinking via FcyR-bearing cells (FIG. 8).
[0078] The OKT3-induced T-cell proliferation was significantly
higher in autologous PBMC cultures incubated for 72-90 h, while
scFv.sub.6 and scFv.sub.10 demonstrated only minor effects in
comparison with 24-h incubation (FIG. 9). In mixed PBMC cultures
(donor A+B) incubated for 72 h without antibody treatment, a mixed
lymphocyte reaction (MLR) developed. Treatment of mixed PBMC
cultures with OKT3 had no effect on MLR, while both scFv-antibodies
were able to suppress MLR in a concentration-dependent manner, thus
reaching the background level at a concentration of 10 .mu.g/ml
(FIG. 9).
EXAMPLE 7
Analyses of Cytokine Release
[0079] For measurement of cytokine secretion by activated
lymphocytes, 2.times.10.sup.6 PBMCs were plated in individual wells
of 24-well plates (Greiner, Frickenhausen, Germany) in RPMI 1640
medium supplemented with 10% heat-inactivated FCS, 2 mM
L-glutamine, b 100 U/ml penicillin G sodium salt and 0.1 mg/ml
streptomycin sulfate (all from Invitrogen, Groningen, The
Netherlands) together with the indicated antibodies. For
determination of secretion of IL-2, TNF-.alpha. and IFN-.gamma.,
aliquots of the culture supernatants were collected after 24 h, 36
h and 72 h, respectively. Cytokine levels were measured in
duplicates using the commercially available ELISA kits for IL-2
(Pharmingen, San Diego, Calif.), TNF-.alpha. and IFN-.gamma.
(Endogen, Cambridge, Mass.).
[0080] In both autologous and mixed PBMC cultures, OKT3 induced a
strong release of IL-2 (FIG. 10), IFN-.gamma.(FIG. 11) and
TNF-.alpha. (FIG. 12). In contrast, the autologous PBMC cultures
treated with scFv.sub.6 and scFv.sub.10, respectively, did not
produce IL-2 (FIG. 10), IFN-.gamma. (FIG. 11) and TNF-.alpha. (FIG.
12). Mixed lymphocyte cultures incubated without antibodies
demonstrated release of significant amounts of cytokines as a
result of allogeneic stimulation. This secretion of IL-2 and
IFN-.gamma. could be suppressed by scFv-antibodies in a
dose-dependent manner (FIGS. 10 and 11). Bivalent scFv.sub.6
demonstrated approximately tenfold higher efficacy than
scFv.sub.10. In contrast, mAb OKT3 had rather induction than
suppression of cytokine release in mixed PBMC cultures.
EXAMPLE 8
Alteration of Surface Antigens on PBMCs Treated with Anti-CD3
Antibodies
[0081] For determination the cell surface expression of the
alpha-subunit of IL-2 receptor (CD25) as an early activation
marker, 2.times.10.sup.6 PBMCs were plated in individual wells of
24-well plates (Greiner, Frickenhausen, Germany) in RPMI 1640
medium supplemented with 10% heat-inactivated FCS, 2 mM
L-glutamine, 100 U/ml penicillin-G sodium salt and 0.1 mg/ml
streptomycin sulfate (all from Invitrogen, Groningen, The
Netherlands) together with the indicated antibodies. The cells were
harvested after 90 h incubation and stained for flow cytometric
analysis with PE-conjugated anti-CD25 mAb B1.49.9 and with the
corresponding isotype controls (all from Beckman-Coulter, Krefeld,
Germany), as described in Example 3. 10.sup.4 lymphocytes were
analyzed with a Beckman-Coulter Epics XL flow cytometer
(Beckman-Coulter, Krefeld, Germany). Mean fluorescence (F) was
calculated using System-II software (Beckman-Coulter, Krefeld,
Germany), and background fluorescence was subtracted.
[0082] PBMCs that were cultured in the presence of OKT3 showed a
strong upregulation of the early activation marker
IL-2R.quadrature. (CD25) on their surface, as determined by flow
cytometry (FIG. 12). In contrast, none of the PBMC cultures treated
either with scFv.sub.6 or scFv.sub.10 showed elevated levels of
CD25 expression (FIG. 13). Thus, these results clearly demonstrate
that, unlike mAb OKT3, scFv.sub.6 and scFv.sub.10 do not posses the
T-cell activating properties.
EXAMPLE 9
Modulation and Coating of TCR/CD3 on Lymphocytes treated with
Anti-CD3 Antibodies
[0083] To measure the modulation and coating of cell surface
TCR/CD3 on lymphocytes, 2.times.10.sup.6 PBMCs were plated in
individual wells of 24-well plates (Greiner, Frickenhausen,
Germany) in RPMI 1640 medium supplemented with 10% heat-inactivated
FCS, 2 mM L-glutamine, 100 U/ml penicillin-G sodium salt and 0.1
mg/ml streptomycin sulfate (all from Invitrogen, Groningen, The
Netherlands) together with the indicated antibodies. The cells were
harvested after 24 h incubation and stained for flow cytometric
analysis with FITC-conjugated OKT3 (Dr. Moldenhauer, German Cancer
Research Center, Heidelberg) or PC5-conjugated
anti-TCR.alpha./.beta. (Beckman-Coulter, Krefeld, Germany) and the
corresponding isotype controls (Beckman-Coulter, Krefeld, Germany).
The cells were counterstained with anti-CD5 antibodies
(Beckman-Coulter, Krefeld, Germany) for T lymphocytes and analyzed
with a Beckman-Coulter Epics XL flow cytometer (Beckman-Coulter,
Krefeld, Germany). Mean fluorescence (F) of OKT3-FITC and TCR-PC5
from CD5-positive cells was calculated using System-II software
(Beckman-Coulter, Krefeld, Germany). Calculation of CD3 modulation
and coating was performed as described previously (Cole, M.S. et
al., 1997, J. Immunol. 159, 3613-3621): % .times. .times. CD
.times. .times. 3 .times. .times. modulation = untreated .times.
.times. cells .times. .times. F .function. ( anti .times. - .times.
TCR ) - treated .times. .times. cells .times. .times. F .function.
( anti .times. - .times. TCR ) untreated .times. .times. cells
.times. .times. F .function. ( anti .times. - .times. TCR ) .times.
100 ##EQU1## % .times. .times. CD .times. .times. 3 .times. .times.
coating = treated .times. .times. cells .times. .times. F
.function. ( anti .times. - .times. TCR ) control .times. .times.
cells .times. .times. F .function. ( anti .times. - .times. TCR ) -
treated .times. .times. cells .times. .times. F .function. ( OKT
.times. .times. 3 ) control .times. .times. cells .function. ( OKT
.times. .times. 3 ) .times. 100 ##EQU1.2## Coating, which is
defined as the number of CD3 molecules on the surface of T
lymphocytes that are antibody bound and therefore not detectable by
FITC-conjugated mAb OKT3, was only observed in one experiment with
the lowest concentration of OKT3 and anti-CD3 scFv.sub.6 (FIG. 14).
CD3 modulation, which represents the fraction of TCR/CD3 complexes
on the surface of T cells that is lost after antibody treatment, is
efficiently (>90%) induced by mAb OKT3 and anti-CD3 scFv.sub.6
at concentrations in the range between 0.1 .mu.g/ml and 10 .mu.g/ml
(FIG. 14). In contrast, the modulation activity of anti-CD3
scFv.sub.10 was much lower and could be observed only at
concentrations above 1 .mu.g/ml (FIG. 14).
Sequence CWU 1
1
17 1 6 PRT Artificial Peptide linker 1 Ser Ala Lys Thr Thr Pro 1 5
2 10 PRT Artificial Peptide linker 2 Ser Ala Lys Thr Thr Pro Lys
Leu Gly Gly 1 5 10 3 5 PRT Artificial Peptide linker 3 Gly Gly Gly
Gly Ser 1 5 4 33 DNA Artificial Primer Bi3sk 4 cagccggcca
tggcgcaggt gcaactgcag cag 33 5 36 DNA Artificial Primer Bi9sk 5
gaagatggat ccagcggccg cagtatcagc ccggtt 36 6 42 DNA Artificial
Primer DP1 6 tcacacagaa ttcttagatc tattaaagag gagaaattaa cc 42 7 40
DNA Artificial Primer DP2 7 agcacacgat atcaccgcca agcttgggtg
ttgttttggc 40 8 34 DNA Artificial Primer OKT_5 8 tattaagata
tcgggtgttg ttttggctga ggag 34 9 32 DNA Artificial Primer 5-NDE 9
gatatacata tgaaatacct attgcctacg gc 32 10 47 DNA Artificial Primer
3-AFL 10 cgaattctta agttagcaca ggcctctaga gacacacaga tctttag 47 11
28 DNA Artificial Primer 5-NAR 11 caccctggcg cccaatacgc aaaccgcc 28
12 46 DNA Artificial Primer 3-NDE 12 ggtatttcat atgtatatct
ccttcttcag aaattcgtaa tcatgg 46 13 52 DNA Artificial Primer skp-3
13 cgaattctta agaaggagat atacatatga aaaagtggtt attagctgca gg 52 14
40 DNA Artificial Primer skp-4 14 cgaattctcg agcattattt aacctgtttc
agtacgtcgg 40 15 35 DNA Artificial Primer His-Xba 15 caggcctcta
gattagtgat ggtgatggtg atggg 35 16 6091 DNA Artificial Plasmid
pSKK3-scFv6 anti-CD3 16 acccgacacc atcgaatggc gcaaaacctt tcgcggtatg
gcatgatagc gcccggaaga 60 gagtcaattc agggtggtga atgtgaaacc
agtaacgtta tacgatgtcg cagagtatgc 120 cggtgtctct tatcagaccg
tttcccgcgt ggtgaaccag gccagccacg tttctgcgaa 180 aacgcgggaa
aaagtggaag cggcgatggc ggagctgaat tacattccca accgggtggc 240
acaacaactg gcgggcaaac agtcgttgct gattggcgtt gccacctcca gtctggccct
300 gcacgcgccg tcgcaaattg tcgcggcgat taaatctcgc gccgatcaac
tgggtgccag 360 cgtggtggtg tcgatggtag aacgaagcgg cgtcgaagcc
tgtaaagcgg cggtgcacaa 420 tcttctcgcg caacgcgtca gtgggctgat
cattaactat ccgctggatg accaggatgc 480 cattgctgtg gaagctgcct
gcactaatgt tccggcgtta tttcttgatg tctctgacca 540 gacacccatc
aacagtatta ttttctccca tgaagacggt acgcgactgg gcgtggagca 600
tctggtcgca ttgggtcacc agcaaatcgc gctgttagcg ggcccattaa gttctgtctc
660 ggcgcgtctg cgtctggctg gctggcataa atatctcact cgcaatcaaa
ttcagccgat 720 agcggaacgg gaaggcgact ggagtgccat gtccggtttt
caacaaacca tgcaaatgct 780 gaatgagggc atcgttccca ctgcgatgct
ggttgccaac gatcagatgg cgctgggcgc 840 aatgcgcgcc attaccgagt
ccgggctgcg cgttggtgcg gatatctcgg tagtgggata 900 cgacgatacc
gaagacagct catgttatat cccgccgtta accaccatca aacaggattt 960
tcgcctgctg gggcaaacca gcgtggaccg cttgctgcaa ctctctcagg gccaggcggt
1020 gaagggcaat cagctgttgc ccgtctcact ggtgaaaaga aaaaccaccc
tggcgcccaa 1080 tacgcaaacc gcctctcccc gcgcgttggc cgattcatta
atgcagctgg cacgacaggt 1140 ttcccgactg gaaagcgggc agtgagcggt
acccgataaa agcggcttcc tgacaggagg 1200 ccgttttgtt ttgcagccca
cctcaacgca attaatgtga gttagctcac tcattaggca 1260 ccccaggctt
tacactttat gcttccggct cgtatgttgt gtggaattgt gagcggataa 1320
caatttcaca caggaaacag ctatgaccat gattacgaat ttctgaagaa ggagatatac
1380 atatgaaata cctattgcct acggcagccg ctggcttgct gctgctggca
gctcagccgg 1440 ccatggcgca ggtgcagctg cagcagtctg gggctgaact
ggcaagacct ggggcctcag 1500 tgaagatgtc ctgcaaggct tctggctaca
cctttactag gtacacgatg cactgggtaa 1560 aacagaggcc tggacagggt
ctggaatgga ttggatacat taatcctagc cgtggttata 1620 ctaattacaa
tcagaagttc aaggacaagg ccacattgac tacagacaaa tcctccagca 1680
cagcctacat gcaactgagc agcctgacat ctgaggactc tgcagtctat tactgtgcaa
1740 gatattatga tgatcattac agccttgact actggggcca aggcaccact
ctcacagtct 1800 cctcagccaa aacaacaccc gatatcgtgc tcactcagtc
tccagcaatc atgtctgcat 1860 ctccagggga gaaggtcacc atgacctgca
gtgccagctc aagtgtaagt tacatgaact 1920 ggtaccagca gaagtcaggc
acctccccca aaagatggat ttatgacaca tccaaactgg 1980 cttctggagt
ccctgctcac ttcaggggca gtgggtctgg gacctcttac tctctcacaa 2040
tcagcggcat ggaggctgaa gatgctgcca cttattactg ccagcagtgg agtagtaacc
2100 cattcacgtt cggctcgggg acaaagttgg aaataaaccg ggctgatact
gcggccgctg 2160 gatcccatca ccatcaccat cactaatcta gaggcctgtg
ctaacttaag aaggagatat 2220 acatatgaaa aagtggttat tagctgcagg
tctcggttta gcactggcaa cttctgctca 2280 ggcggctgac aaaattgcaa
tcgtcaacat gggcagcctg ttccagcagg tagcgcagaa 2340 aaccggtgtt
tctaacacgc tggaaaatga gttcaaaggc cgtgccagcg aactgcagcg 2400
tatggaaacc gatctgcagg ctaaaatgaa aaagctgcag tccatgaaag cgggcagcga
2460 tcgcactaag ctggaaaaag acgtgatggc tcagcgccag acttttgctc
agaaagcgca 2520 ggcttttgag caggatcgcg cacgtcgttc caacgaagaa
cgcggcaaac tggttactcg 2580 tatccagact gctgtgaaac ccgttgccaa
cagccaggat atcgatctgg ttgttgatgc 2640 aaacgccgtt gcttacaaca
gcagcgatgt aaaagacatc actgtcgacg tactgaaaca 2700 ggttaaataa
tgctcgagga actgctgaaa catctgaagg agctgcttaa aggtgagttc 2760
tgataagctt gacctgtgaa gtgaaaaatg gcgcacattg tgcgacattt tttttgtctg
2820 ccgtttaccg ctactgcgtc acggatccgg ccgaacaaac tccgggaggc
agcgtgatgc 2880 ggcaacaatc acacggattt cccgtgaacg gtctgaatga
gcggattatt ttcagggaaa 2940 gtgagtgtgg tcagcgtgca ggtatatggg
ctatgatgtg cccggcgctt gaggctttct 3000 gcctcatgac gtgaaggtgg
tttgttgccg tgttgtgtgg cagaaagaag atagccccgt 3060 agtaagttaa
ttttcattaa ccaccacgag gcatccctat gtctagtcca catcaggata 3120
gcctcttacc gcgctttgcg caaggagaag aaggccatga aactaccacg aagttccctt
3180 gtctggtgtg tgttgatcgt gtgtctcaca ctgttgatat tcacttatct
gacacgaaaa 3240 tcgctgtgcg agattcgtta cagagacgga cacagggagg
tggcggcttt catggcttac 3300 gaatccggta agtagcaacc tagaggcggg
cgcaggcccg ccttttcagg actgatgctg 3360 gtctgactac tgaagcgcct
ttataaaggg gctgctggtt cgccggtagc ccctttctcc 3420 ttgctgatgt
tgtgggaatt tcgagcaaga cgtttcccgt tgaatatggc tcataacacc 3480
ccttgtatta ctgtttatgt aagcagacag ttttattgtt catgatgata tatttttatc
3540 ttgtgcaatg taacatcaga gattttgaga cacaacgtgg ctttcccccc
cccccctgca 3600 gggggggggg ggcgctgagg tctgcctcgt gaagaaggtg
ttgctgactc ataccaggcc 3660 tgaatcgccc catcatccag ccagaaagtg
agggagccac ggttgatgag agctttgttg 3720 taggtggacc agttggtgat
tttgaacttt tgctttgcca cggaacggtc tgcgttgtcg 3780 ggaagatgcg
tgatctgggg atccccacgc gccctgtagc ggcgcattaa gcgcggcggg 3840
tgtggtggtt acgcgcagcg tgaccgctac acttgccagc gccctagcgc ccgctccttt
3900 cgctttcttc ccttcctttc tcgccacgtt cgccggcttt ccccgtcaag
ctctaaatcg 3960 gggcatccct ttagggttcc gatttagtgc tttacggcac
ctcgacccca aaaaacttga 4020 ttagggtgat ggttcacgta gtgggccatc
gccctgatag acggtttttc gccctttgac 4080 gttggagtcc acgttcttta
atagtggact cttgttccaa actggaacaa cactcaaccc 4140 tatctcggtc
tattcttttg atttataagg gattttgccg atttcggcct attggttaaa 4200
aaatgagctg atttaacaaa aatttaacgc gaattttaac aaaatattaa cgtttacaat
4260 ttcaggtggc gaattccccg gggaattcac ttttcgggga aatgtgcgcg
gaacccctat 4320 ttgtttattt ttctaaatac attcaaatat gtatccgctc
atgagacaat aaccctgata 4380 aatgcttcaa taatattgaa aaaggaagag
tatgagtatt caacatttcc gtgtcgccct 4440 tattcccttt tttgcggcat
tttgccttcc tgtttttgct cacccagaaa cgctggtgaa 4500 agtaaaagat
gctgaagatc agttgggtgc acgagtgggt tacatcgaac tggatctcaa 4560
cagcggtaag atccttgaga gttttcgccc cgaagaacgt tttccaatga tgagcacttt
4620 taaagttctg ctatgtggcg cggtattatc ccctattgac gccgggcaag
agcaactcgg 4680 tcgccgcata cactattctc agaatgactt ggttgagtac
tcaccagtca cagaaaagca 4740 tcttacggat ggcatgacag taagagaatt
atgcagtgct gccataacca tgagtgataa 4800 cactgcggcc aacttacttc
tgacaacgat cggaggaccg aaggagctaa ccgctttttt 4860 gcacaacatg
ggggatcatg taactcgcct tgatcgttgg gaaccggagc tgaatgaagc 4920
cataccaaac gacgagcgtg acaccacgat gcctgtagca atggcaacaa cgttgcgcaa
4980 actattaact ggcgaactac ttactctagc ttcccggcaa caattaatag
actggatgga 5040 ggcggataaa gttgcaggac cacttctgcg ctcggccctt
ccggctggct ggtttattgc 5100 tgataaatct ggagccggtg agcgtgggtc
tcgcggtatc attgcagcac tggggccaga 5160 tggtaagccc tcccgtatcg
tagttatcta cacgacgggg agtcaggcaa ctatggatga 5220 acgaaataga
cagatcgctg agataggtgc ctcactgatt aagcattggt aactgtcaga 5280
ccaagtttac tcatatatac tttagattga tttaaaactt catttttaat ttaaaaggat
5340 ctaggtgaag atcctttttg ataatctcat gaccaaaatc ccttaacgtg
agttttcgtt 5400 ccactgagcg tcagaccccg tagaaaagat caaaggatct
tcttgagatc ctttttttct 5460 gcgcgtaatc tgctgcttgc aaacaaaaaa
accaccgcta ccagcggtgg tttgtttgcc 5520 ggatcaagag ctaccaactc
tttttccgaa ggtaactggc ttcagcagag cgcagatacc 5580 aaatactgtc
cttctagtgt agccgtagtt aggccaccac ttcaagaact ctgtagcacc 5640
gcctacatac ctcgctctgc taatcctgtt accagtggct gctgccagtg gcgataagtc
5700 gtgtcttacc gggttggact caagacgata gttaccggat aaggcgcagc
ggtcgggctg 5760 aacggggggt tcgtgcacac agcccagctt ggagcgaacg
acctacaccg aactgagata 5820 cctacagcgt gagctatgag aaagcgccac
gcttcccgaa gggagaaagg cggacaggta 5880 tccggtaagc ggcagggtcg
gaacaggaga gcgcacgagg gagcttccag ggggaaacgc 5940 ctggtatctt
tatagtcctg tcgggtttcg ccacctctga cttgagcgtc gatttttgtg 6000
atgctcgtca ggggggcgga gcctatggaa aaacgccagc aacgcggcct ttttacggtt
6060 cctggccttt tgctggcctt ttgctcacat g 6091 17 267 PRT Artificial
scFv6 anti-CD3 17 Met Lys Tyr Leu Leu Pro Thr Ala Ala Ala Gly Leu
Leu Leu Leu Ala 1 5 10 15 Ala Gln Pro Ala Met Ala Gln Val Gln Leu
Gln Gln Ser Gly Ala Glu 20 25 30 Leu Ala Arg Pro Gly Ala Ser Val
Lys Met Ser Cys Lys Ala Ser Gly 35 40 45 Tyr Thr Phe Thr Arg Tyr
Thr Met His Trp Val Lys Gln Arg Pro Gly 50 55 60 Gln Gly Leu Glu
Trp Ile Gly Tyr Ile Asn Pro Ser Arg Gly Tyr Thr 65 70 75 80 Asn Tyr
Asn Gln Lys Phe Lys Asp Lys Ala Thr Leu Thr Thr Asp Lys 85 90 95
Ser Ser Ser Thr Ala Tyr Met Gln Leu Ser Ser Leu Thr Ser Glu Asp 100
105 110 Ser Ala Val Tyr Tyr Cys Ala Arg Tyr Tyr Asp Asp His Tyr Ser
Leu 115 120 125 Asp Tyr Trp Gly Gln Gly Thr Thr Leu Thr Val Ser Ser
Ala Lys Thr 130 135 140 Thr Pro Asp Ile Val Leu Thr Gln Ser Pro Ala
Ile Met Ser Ala Ser 145 150 155 160 Pro Gly Glu Lys Val Thr Met Thr
Cys Ser Ala Ser Ser Ser Val Ser 165 170 175 Tyr Met Asn Trp Tyr Gln
Gln Lys Ser Gly Thr Ser Pro Lys Arg Trp 180 185 190 Ile Tyr Asp Thr
Ser Lys Leu Ala Ser Gly Val Pro Ala His Phe Arg 195 200 205 Gly Ser
Gly Ser Gly Thr Ser Tyr Ser Leu Thr Ile Ser Gly Met Glu 210 215 220
Ala Glu Asp Ala Ala Thr Tyr Tyr Cys Gln Gln Trp Ser Ser Asn Pro 225
230 235 240 Phe Thr Phe Gly Ser Gly Thr Lys Leu Glu Ile Asn Arg Ala
Asp Thr 245 250 255 Ala Ala Ala Gly Ser His His His His His His 260
265
* * * * *