Variant B7 co-stimulatory molecules
The invention provides polynucleotides and polypeptides encoded therefrom having advantageous properties, including an ability of the polypeptides to preferentially bind a CD28 or CTLA-4 receptor at a level greater or less than the ability of human B7-1 to bind CD28 or CTLA-4, or to induce or inhibit altered level of T cell proliferation response greater compared to that generated by human B7-1. The polypeptides and polynucleotides of the invention are useful in therapeutic and prophylactic treatment methods, gene therapy applications, and vaccines.
1. An isolated or recombinant polypeptide variant of an extracellular domain of a wild-type primate B7-1 comprising a polypeptide sequence that has at least 95% identity to the polypeptide sequence of the extracellular domain of the wild-type primate B7-1 and differs from the polypeptide sequence of the extracellular domain of the wild-type primate B7-1 by the substitution of an amino acid other than alanine at an amino acid residue position corresponding to position 65 of the polypeptide sequence of wild-type human B7-1 (SEQ ID NO:278), wherein said polypeptide variant has a CTLA-4/CD28 binding affinity ratio greater than the CTLA-4/CD28 binding affinity ratio of the extracellular domain of the wild-type primate B7-1.
2. The polypeptide variant of claim 1 , wherein the substituted amino acid is selected from the group consisting of histidine, arginine, lysine, proline, phenylalanine, and tryptophan.
3. The polypeptide variant of claim 1 , wherein the primate B7-1 is human B7-1.
4. The polypeptide variant of claim 2 , wherein the substituted amino acid is histidine.
5. The polypeptide variant of claim 2 , wherein the substituted amino acid is histidine.
6. The polypeptide variant of claim 3 , wherein the variant has a CTLA-4/CD28 binding affinity ratio greater than the CTLA-4/CD28 binding affinity ratio of the extracellular domain of wild-type human B7-1.
7. The polypeptide variant of claim 1 , wherein the variant induces less T cell proliferation compared to T cell proliferation induced by the extracellular domain of wild-type primate B7- 1.
8. The polypeptide variant of claim 5 , wherein the variant has a CTLA-4/CD28 binding affinity ratio greater than the CTLA-4/CD28 binding affinity ratio of the extracellular domain of wild-type human B7-1 and/or induces less T cell proliferation compared to T cell proliferation induced by the extracellular domain of wild-type human B7-1.
9. The polypeptide variant of claim 1 , wherein the polypeptide comprises a fusion protein comprising at least one additional amino acid sequence.
10. The polypeptide variant of claim 9 , wherein the at least one additional amino acid sequence comprises at least one Ig polypeptide.
11. The polypeptide variant of claim 10 , wherein the at least one Ig polypeptide comprises at least one human IgG polypeptide comprising an Fc hinge, a CH2 domain, and a CH3 domain.
12. The polypeptide variant of claim 8 , which further comprises at least one Ig polypeptide.
13. A multimer comprising at least two polypeptide variants of claim 1 .
14. A multimer comprising at least two polypeptide variants of claim 5 .
15. An isolated or recombinant polypeptide variant of a mature domain of a wild-type primate B7-1 comprising a polypeptide sequence that has at least 95% identity to the polypeptide sequence of the mature domain of the wild-type primate B7-1 and differs from the polypeptide sequence of the mature domain of the wild-type primate B7-1 by the substitution of an amino acid other than alanine at an amino acid residue position corresponding to position 65 of the polypeptide sequence of wild-type human B7-1 (SEQ ID NO:278), wherein said polypeptide variant has a CTLA-4/CD28 binding affinity ratio greater than the CTLA-4/CD28 binding affinity ratio of the mature domain of the wild-type primate B7-1.
16. The polypeptide variant of claim 15 , wherein the substituted amino acid is selected from the group consisting of histidine, arginine, lysine, proline, phenylalanine, and tryptophan.
17. The polypeptide variant of claim 15 , wherein the primate B7-1 is human B7-1.
18. The polypeptide variant of claim 17 , wherein the substituted amino acid is histidine.
19. The polypeptide variant of claim 17 , wherein the variant has a CTLA-4/CD28 binding affinity ratio greater than the CTLA-4/CD28 binding affinity ratio of the mature domain of wild-type human B7-1.
20. The polypeptide variant of claim 15 , wherein the variant induces less T cell proliferation compared to T cell proliferation induced by the mature domain of wild-type primate B7-1.
21. The polypeptide variant of claim 18 , wherein the variant has a CTLA-4/CD28 binding affinity ratio greater than the CTLA-4/CD28binding affinity ratio of the mature domain of wild-type human B7-1 and/or induces less T cell proliferation compared to T cell proliferation induced by the mature domain of wild-type human B7-1.
22. An isolated or recombinant polypeptide variant of a wild-type primate B7-1 comprising a polypeptide sequence that has at least 95% identity to the full-length polypeptide sequence of the wild-type primate B7-1 and differs from the polypeptide sequence of the wild-type primate B7-1 by the substitution of an amino acid other than alanine at an amino acid residue position corresponding to position 65 of the sequence of human B7-1 (SEQ ID NO:278), wherein said polypeptide variant has a CTLA-4/CD28 binding affinity ratio greater than the CTLA-4/CD28 binding affinity ratio of the wild-type primate B7-1.
23. The polypeptide variant of claim 22 , wherein the substituted amino acid is selected from the group consisting of histidine, arginine, lysine, proline, phenylalanine, and tryprophan.
24. The polypeptide variant of claim 23 , wherein the primate B7-1 is human B7-1.
25. The polypeptide variant of claim 24 , wherein the substituted amino acid is histidine.
26. The polypeptide variant of claim 25 , wherein the variant has a CTLA-4/CD28 binding affinity ratio greater than the CTLA-4/CD28 binding affinity ratio of wild-type human B7-1.
27. The polypeptide variant of claim 25 , wherein the variant induces less T cell proliferation compared to T cell proliferation induced by the wild-type primate B7-1.
28. A composition comprising the polypeptide variant of claim 1 and a pharmaceutically acceptable excipient or carrier.
29. A composition comprising the polypeptide variant of claim 8 and a pharmaceutically acceptable excipient or carrier.
30. A composition comprising the polypeptide variant of claim 15 and a pharmaceutically acceptable excipient or carrier.