CD95-deficient cells of Jurkat/A4 subline are resistant to drug-induced apoptosis

We developed unique CD95-deficient subline (Jurkat/A4) from the parent Jurk at/WT cell line by continuous culture in medium containing apoptosis-induci ng anti-CD95 MAb, clone IPO-4 (IgM). In contrast to the parental Jarkat/WT line, which displays relatively high expression of CD95 (60-80% antigene-po sitive cells), cell-surface expression of the CD95 was entirely negative in the Jurkat/A4 cell line (only 4% of antigene-positive cells). The Jurkat/A 4 cells are resistant to induction of apoptosis by both anti-CD95 mAb IPO-4 and chemotherapeutic drugs, whereas the wild type clone Jurkat/WT undergoe s time-dependent apoptosis. Thus, these results suggest the possible partic ipation of CD95 pathway in the development of drug-induced apoptosis.