EBV-CTLs express high levels of Fas and are susceptible to Fas-mediated apoptosis. EBV-CTLs (A), freshly isolated CD3⁺ cells (B), and Con-A blasts (C) were stained with anti-CD95-PE (solid line) or isotype control (dashed lines). (D) The mean fluorescence intensity MFI for CD95 in EBV-CTLs, freshly isolated CD3⁺ cells, and Con-A blasts are shown. Data are representative of 4 different donors for MNCs and 7 donors for the CTL lines (^*P < .001; ^**P = .002). (E) Fas-mediated apoptosis is shown in EBV-CTLs, Con-A blasts, and isolated CD3⁺ cells incubated with CH-11 antibody (40 ng/mL; ▦) or in media alone (□). Data represent the mean ± SD of 6 different donors for EBV-CTLs and 4 different donors for isolated CD3⁺ cells and Con-A blasts (^*P < .001).