背景资料：ICOS ligand is a protein that in humans is encoded by the ICOSLG gene. ICOSLG has also been designated as CD275 (cluster of differentiation 275). Acts as a costimulatory signal for T-cell proliferation and cytokine secretion; induces also B-cell proliferation and differentiation into plasma cells. Could play an important role in mediating local tissue responses to inflammatory conditions, as well as in modulating the secondary immune response by co-stimulating memory T-cell function.