Reproducibility of Nef effects on the antiviral activities of HIV-1–specific CTL clones on repeat testing. Five CTL clones were tested as described in Figure 1. The means (± SEM) are plotted for multiple independent experiments with each clone. Comparisons revealed that 68A62, S1-SL9-3.23T, 18030D23, and 42758-RL10-3.22 were statistically indistinguishable from each other (2-tailed t test P ≥ .26 for all comparisons between these clones), but clone S16-RY11-10.41 was statistically distinct from the others (P ≤ .01 for all comparisons to the other clones).