Figure 2.

EL4 and EL4ρ° cells were equally sensitive to CTLs. (A) CD8⁺ T cells were purified by MACS from the spleens of C57BL/6 granzyme A^−/− mice after 8 d of infection with LCMV, labeled with cell tracker green (CTG) and tested against EL4 or EL4-ρ° cells for 2 h at an effector:target (E:T) ratio of 10:1 in the presence (+gp+CTL) or absence (−gp+CTL) of the LCMV peptide gp33. Then, target cells were gated as the CTG-negative population and, at time 0 (Ctr) or after the 2 h incubation with the CTL, plasma membrane intregrity was tested by nuclear 7-AAD incorporation and PS exposure by labeling with annexin-V-PE and flow cytometry. Numbers in the dot-plots show the percentage of cells in each quadrant. (B) Summary of all experiments performed. Antiviral CTL from gzmA^−/− mice were incubated with EL4 or EL4-ρ° cells, as indicated in A. The cytolytic activity was evaluated by the percentages of annexin-V⁺ cells. Data showed the mean ± SD of at least three different experiments.