Patent ID: 7432351

Claim:
A purified variant B7-H1 polypeptide which is a variant of a wild-type B7-H1 polypeptide, wherein said wild-type B7-H1 polypeptide binds to PD-1 and has the amino acid sequence set forth in SEQ ID NO:4, wherein said variant B7-H1 polypeptide comprises a substitution of the amino acid at position 67, 126, 37, 115, 124, 31, 49, 62, 98, or 129 of SEQ ID NO:4 and has binding affinity for PD-1 that is detectable by ELISA but is reduced by at least 50 percent as compared to the binding affinity of said wild-type B7H1 polypeptide for PD-1.