Fig. 2. Blocking of CD95/Fas has no effect on apoptin-induced cell death. (A) Flow cytometry analysis of apoptosis in Jurkat cells, either grown in control medium or incubated with a human anti-APO-1-IgG1 (a neutralizing antibody that blocks the interaction of CD95/APO-1/Fas and the ligand), treated with TAT-apoptin for the indicated time points. To maintain the blockage, treatment with the blocking antibody was repeated every 8 hours. To exclude solvent- or TAT-peptide-related effects, some control cells were treated with recombinant TAT-GFP (1 µM) instead of TAT-apoptin. (B) Control experiment to assess cell death mediated by CD95. Both control cells and the Fas-neutralized cells were treated with an anti-Fas (IgM) antibody, and cell death was measured after 8 hours.