The effect of blocking antibody to FasL and a caspase inhibitor on CTL-mediated apoptosis of CLL B cells.

(A) CTL assays were performed as described in “Materials and methods” at an E/T ratio of 10:1, with 2 exceptions: (1) CTL effectors were preincubated for 45 minutes with MOPC21 control (black bars) or with NOK-2 anti-FasL mAb (hatched bars), or (2) the CTL assay was performed in the presence of 20 μmol/L z-VAD-fmk (open bars). Results are the mean plus or minus SD from 3 separate experiments. (B) CHO-FasL effector-mediated apoptosis of Jurkat cells in which effectors were either preincubated with MOPC21 control (black bar) or NOK-2 (hatched bar). Jurkat cells were also treated with anti-Fas mAb CH-11 for 4 hours in the absence (black bar) or presence (open bar) of 20 μmol/L z-VAD-fmk.