Influence of LF 15-0195 on Jurkat T-cell apoptosis triggered by an agonistic anti-CD95 Ab.

(A) Hoechst 33342 staining of the nuclear chromatin of Jurkat T cells exposed to either vehicle (control) or LF 15-0195 (0.1 μM) for 3 days, then treated with CH11 anti-CD95 Ab (25 ng/mL for 3 hours). Original magnifications, × 40. (B) A similar experiment was performed with Jurkat T cells exposed to either indicated concentrations (left panel) or 0.1 μM (right panel) LF 15-0195 for 3 days, then treated with indicated concentration of CH11 Ab for various times. (Right panel: ■ indicates control cells; ▪, LF 15-0195–pretreated cells.) Results are expressed as the means ± SD of 3 independent experiments in triplicate. (C) Top panel: agarose gel electrophoresis of DNA from Jurkat T cells exposed to either vehicle (control) or LF 15-0195 (0.1 μM) for 3 days, then exposed to CH11 mAbs (25 ng/mL) for indicated times. Bottom panel: simultaneous analysis of poly(ADP-ribose)polymerase by Western blotting (loading control: Hsc70). Asterisk indicates the cleavage fragments. (D) Caspase activities were explored by studying the cleavage of indicated peptides at indicated times after the beginning of CH11 Ab treatment (25 ng/mL). ■ indicates control cells; ▪, LF 15-0195–treated cells. One representative of 3 independent experiments is shown (means ± SD).