Inducible T-cell costimulator (ICOS)

Enhances all basic T-cell answers to a foreign antigen, namely proliferation, secretion of lymphokines, up- regulation of molecules that mediate cell-cell interaction, and effective help for antibody secretion by B-cells. Essential both for effective interaction between T and B-cells and for normal antibody responses to T-cell dependent antigens.

Does not up- regulate the production of interleukin-2, but superinduces the synthesis of interleukin-10. Prevents the apoptosis of pre- activated T-cells.