FIG. 1.
Differential suppressive activity of CD8+ T cells of HIV-1-seronegative individuals (squares), CTL clones (diamonds), and asymptomatic HIV-1-seropositive individuals (circles). Supernatants of CD3-stimulated CD8+ T cells were collected after 2, 4, 8, and 16 h, diluted 1:2 in R20, and added to H9 cells acutely infected by HIVIIIB; 1 ml of H9 supernatant was removed when 1 ml of 1:2-diluted supernatants was added at days 3 and 6. The supernatant of the inhibition test was collected and tested for p24 production after 9 days in culture. Percentage of inhibition was calculated against an untreated control. The asterisks indicate a statistically significant difference of cells from HIV-1-seronegative individuals (n = 6) against both cells from HIV-1-seropositive individuals (n = 6) and CTL (n = 5) (∗, P < 0.05; ∗∗, P < 0.01: Fisher's exact test). Error bars of at least five independent experiments are shown.