Patent ID: 7235631

Claim:
A purified polypeptide consisting of: (a) a variant of a wild-type ICOS amino acid sequence consisting of an extracellular domain of wild-type ICOS, the wild-type ICOS extracellular domain being SEQ ID NO:10 or SEQ ID NO:9, the variant: consisting of an amino acid sequence that differs by one or more amino acid substitutions from, but is at least 85% homologous to, its corresponding wild-type ICOS amino acid sequence; and having altered affinity for human B7-H2 (SEQ ID NO:43) compared to its corresponding wild-type ICOS amino acid sequence, wherein said affinity for human B7-H2 is increased by at least 10% relative to the affinity of the corresponding wild-type ICOS amino acid sequence for human B7-H2; or (b) the variant of (a) and: (I) a peptide sequence unrelated to ICOS attached to the N-terminus of the variant of (a); (II) a peptide sequence unrelated to ICOS attached to the C-terminus of the variant of (a); or (III) a peptide sequence unrelated to ICOS attached to the N-terminus of the variant of (a) and a second peptide sequence unrelated to ICOS attached to the C-terminus of the variant of (a).