κaAPCs eliminate CTLs in an antigen-specific fashion. PKH26-labeled activated Fas⁺ effector-memory CTLs (■) and PKH67-labeled CMVpp65-specific CTLs (▒) from the same donor were mixed to a 1:1 ratio and cocultured with ^CMVpp65κaAPCs for 48 hours. Control cultures were treated with ^unloadedκaAPCs or 1 μg/mL of soluble α-Fas IgM (clone CH11). Minimal loss of viable cells was determined in untreated mixed CTL cultures (T_mix). Numbers of viable CTLs, (% viable cells = (% treated cells × 100%)/% untreated cells) for each CTL population of the T_mix are depicted. The illustrating graph is derived from 1 representative experiment out of 3 independent experiments.