ICOS Ligand, Mouse IgG2a Fc Fusion Protein (Inducible T-cell Co-stimulator Ligand, ICOSL, ICOS-L, IC

The inducible costimulator CD278 (ICOS) is similar to human CD28 (24% homology), and plays an analogous role in the T cell activation process. Unlike CD28, CD278 is only expressed on activated T cells. Secondary signaling through CD28 or CD278 results in discrete cytokine secretion profiles by the activated T cells (1). Engagement of CD152 (CTLA-4) anergizes cells costimulated with either CD28 and CD278 (2). Signaling through CD278 is particularly important in progression of TH2 immune response (5). The receptor for human CD278 (ICOS) is CD275 (GL50, ICOS L), a member of the B7 family sharing ~20% homology with CD80 (B7-1) and CD86 (B7-2) (3). Two RNA splice variants exist for this molecule, differing only in the cytoplasmic domain (4). Blockade of the CD278-CD275 interaction in mice improves allograft survival (6) and reduces EAE (7). Molecular Structure:  A soluble dimeric fusion protein consisting of the extracellular (240aa) domain of  human CD275 (GL50, ICOSL, B7-H2, B7RP-1) fused to murine IgG2a Fc (232 aa), with a predicted monomeric molecular weight of 53.3kD. , Reactivity:, Binds to recombinant and native CD278 (ICOS) in ELISA and Flow Cytometry. Its binding is blocked by pre-incubation with soluble recombinant CD278-muIg. Applications: Suitable for use in ELISA and Flow Cytometry. Other applications not tested. Recommended Dilution: Optimal dilutions to be determined by the researcher. Storage and Stability: May be stored at 4°C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Aliquots are stable for 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.