ATG-induced apoptosis is inhibited by CsA and requires protein synthesis. PBL were incubated for 3 days in the presence of PHA (5 μg/mL). Dead cells were removed and viable cells were incubated for 3 hours with CsA (250 ng/mL) or CHX (0.5 μg/mL) before treatment with ATG no. 95-07 (10 μg/mL) or CH11 (1 μg/mL). Apoptosis was determined by fluorescence microscopy after staining with Hoechst 33342. Results are expressed as mean ± SD of three different experiments.