Anti-CD28 humanized antibodies
The invention relates to humanized antibodies directed against the human lymphocyte receptor CD28. When used in a monovalent form these antibodies are antagonists, i.e. capable of blocking of the CD28/B7 interaction, without activating CD28. These antibodies can be used in particular as therapeutic agents for blocking T cell activation through the CD28 receptor.
1. An anti-CD28 antibody selected from the group consisting of:
(a) an antibody having a CD28-binding site consisting of:
a heavy chain variable domain of SEQ ID NO: 1; and
a light chain variable domain of SEQ ID NO: 2, and
(b) an antibody having a CD28-binding site consisting of:
a heavy chain variable domain having all three complementarity determining regions (CDRs) of the variable domain of SEQ ID NO: 1; and
a light chain variable domain having all three CDRs of the variable domain of SEQ ID NO: 2.
2. The antibody of claim 1 , which is a monovalent antibody.
3. The monovalent antibody of claim 2 , which is a heterodimer of:
a first protein chain having the sequence of amino-acids 21-251 of SEQ ID NO: 4; and
a second protein chain having the sequence of amino-acids 21-234 of SEQ ID NO: 6.
4. The monovalent antibody of claim 2 , which is a heterodimer of:
(I) a first protein chain consisting essentially of, from its N-terminus to its C-terminus:
i: a region A which is a heavy chain variable domain of SEQ ID NO: 1; and
ii: a region B consisting of a peptide linker followed by the CH2 and CH3 domains of an IgG immunoglobulin, and
(II) a second protein chain consisting essentially of, from its N-terminus to its C-terminus:
i: a region A′ which is a light chain variable domain of SEQ ID NO: 2; and
ii: a region B identical to the region B of the first protein chain.
5. The monovalent antibody of claim 4 , wherein the peptide linker is selected from the group consisting of:
a peptide of SEQ ID NO: 7; and
a peptide of SEQ ID NO: 8.
6. The monovalent antibody of claim 4 , wherein the CH2 and CH3 domains are those of an immunoglobulin of the IgG4 subclass.
7. The monovalent antibody according to claim 6 , which is selected from the group consisting of:
a monovalent antibody wherein the polypeptide sequence of the first protein chain is the sequence of amino-acids 21-368 of SEQ ID NO: 10, and the polypeptide sequence of the second protein chain is the sequence of amino-acids 21-355 of SEQ ID NO: 12; and
a monovalent antibody wherein the polypeptide sequence of the first protein chain is the sequence of amino-acids 21-373 of SEQ ID NO: 14, and the polypeptide sequence of the second protein chain is the sequence of amino-acids 21-360 of SEQ ID NO: 16.
8. The monovalent antibody of claim 3 wherein the second protein chain comprises a variable domain of SEQ ID NO: 2.
9. A polynucleotide selected from the group consisting of:
(a) a polynucleotide encoding a polypeptide having all the CDRs of SEQ ID NO: 1;
(b) a polynucleotide encoding a polypeptide having all the CDRs of SEQ ID NO: 2; and
(c) a polynucleotide encoding an antibody of claim 1 .
10. A composition comprising the antibody of claim 2 and a pharmaceutically acceptable excipient.
11. A method of treating a pathological condition selected from the group consisting of transplant rejection, chronic allograft vasculopathy, and graft-versus-host disease in a subject in need thereof comprising administering the anti-CD28 monvalent antibody of claim 2 to the subject.
12. The monovalent antibody of claim 3 wherein the second protein chain comprises a variable domain of SEQ ID NO: 2 where X represents an alanine or an asparagine residue.
13. The monovalent antibody of claim 12 which is pegylated.
14. The antibody of claim 1 , wherein the heavy chain variable domain further comprises a Q residue at the N-terminal end.