B7-H3, a member of the B7 family of immunomodulatory molecules, is overexpressed in a wide range of solid cancers.B7-H3 binds to activated T cells via an as yet unidentified receptor. In assays using sub-optimal amount so anti-CD3 stimulation, 2Ig?B7?H3 enhances T cell proliferation, T cell interferon-gamma (IFN-gamma) production, and cytotoxic T cells induction.