Purity: > 90% by SDS - PAGE Format: Liquid. 20mM MES buffer (pH 5.5) containing 40% glycerol, 2mM DTT, 1mM EDTA 0.1M NaCl. ICOS, also known as inducible T-cell costimulator, is a member of the CD28 family of immune-assisted stimulatory receptors. The interaction of B7-H2 / ICOS plays a crucial role in Th cell differentiation, T-B cell interaction and humoral immune response essential for the formation of reproductive centers and the production of cytokine IL-4. In addition, this protein is more potent in inducing IL-10 production, a cytokine important for the inhibitory function of T regulatory cells. The B7-1 / B7-2-CD28 / CTLA-4 and ICOS-B7RP-1 pathways provide an important second signal that can regulate the activation, inhibition and fine regulation of T-lymphocyte responses. It stimulates production of Th1 and Th2 cytokines, but may play a role in the generation of Th2 cells. Recombinant human ICOS, fused to hIgG-His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.