Patent ID: 7521532

Claim:
An isolated polypeptide selected from the group consisting of: a) an isolated fragment of a polypeptide comprising the amino acid sequence of SEQ ID NO: 6, wherein the fragment is a biologically active fragment that has the ability to costimulate T cell proliferation, bind to murine ICOS or human ICOS on a T cell, or bind an antibody which recognizes a polypeptide comprising the amino acid sequence of SEQ ID NO: 6; b) a polypeptide comprising the amino acid sequence of SEQ ID NO: 6, wherein the polypeptide is encoded by a nucleic acid molecule which hybridizes to the complement of a nucleic acid molecule consisting of SEQ ID NO: 5 in 6×sodium chloride/sodium citrate (SSC) at about 45° C., followed by one or more washes in 0.2×SSC, 0.1% SDS at 50-65° C., and further wherein the polypeptide has the ability to costimulate T cell proliferation, bind to murine ICOS or human ICOS on a T cell, or bind an antibody which recognizes a polypeptide comprising the amino acid sequence of SEQ ID NO: 6; c) a polypeptide which is encoded by a nucleic acid molecule which is at least 90% identical across its entire length to the coding region of the nucleotide sequence of SEQ ID NO: 5, wherein the polypeptide has the ability to costimulate T cell proliferation, bind to murine ICOS or human ICOS on a T cell, or bind an antibody which recognizes a polypeptide comprising the amino acid sequence of SEQ ID NO: 6; and d) a polypeptide comprising an amino acid sequence which is at least 90% identical across the entire length to the amino acid sequence of SEQ ID NO: 6, wherein the polypeptide has the ability to costimulate T cell proliferation, bind to murine ICOS or human ICOS on a T cell, or bind an antibody which recognizes a polypeptide comprising the amino acid sequence of SEQ ID NO: 6.