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).
Isotype: Murine IgG1 Kappa
Immunogen: Human Raji cells, recombinant human CD275-muIg
Specificity: Antibody ANC4E3 binds to recombinant CD275 in EIA. It does not block the interaction between recombinant CD278 and CD275.
References:
1) Beier, K.C., R.A. Kroczek, et al. 2000, Eur J Immunol. 30(12):3707-3717.
2) Riley, J.L., C.H. June, et al. 2001, J. Immunol. 166: 4943-4948.
3) Ling, V., M. Collins, et al. 2000, J. Immunol. 164: 1653-1657.
4) Ling, V., M. Collins, et al. 2001, J. Immunol. 166: 7300-7308.
5) K.C. Beier, et al, (2000) Eur J Immunol 30: 3707-3717.
6) E. Ozkaynak, et al, (2001) Nat Immunol 2: 591-596.
7) J.B. Rottman, et al, (2001) Nat Immunol 2: 605-611.
