Recombinant FAS antigen/ CD95 purified from E. coli is a single non-glycosilated polypeptide chain containing amino acids 157-320 of Fas antigen (base pairs 713-1190 of cDNA sequence). The recombinant CD95 is fused to C-terminal 6-histidine amino acids.The FAS antigen is purified by proprietary chromatographic techniques.
FAS / CD95 is a 36kDa transmembrane type I receptor, which belongs to the NF/NGF receptor super-family. It is a potent inducer of apoptosis in cells of the immune system upon interaction with its natural ligand, CD95L. Althoµgh the CD95/CD95L system could play a role in tumor regression, tumor cells seem to down-regulate CD95 expression as a mechanism of resistance to CD95L-induced killing by T lymphocytes and NK cells. The Fas antigen is expressed on the surface of various cell types, including activated T and B lymphocytes and T lymphoblastoid cell line. CD95 is also expressed in a broad panel of non-transformed cells outside the immune system.