FIG. 2.

X4 but not R5 HIV-1 induces pronounced apoptosis and depletion among CD4 T cells. Human lymphoid cultures ex vivo were infected with the R5 strain 1/85 or 49-5, the R5X4 strain 7/86, or the X4 strain NL4-3 or kept uninfected. (A) At day 12, apoptosis among CD4 and CD8 T cells was determined by using annexin V staining. (B) CD4 T-cell depletion displayed as CD4/CD8 ratio. (C) Viral replication was monitored in the same infections by assessing the p24 concentration in the culture medium at days 1, 4, 7, 10, and 13 after infection, using an anti-p24 ELISA. Shown are the mean values (n = 3) with standard errors of the means from a representative experiment from among six experiments with different donor tissue.