Inhibition of HIV replication in PBLs by flavopiridol. Isolated PBLs from three independent donors (A, B and C) were infected with HIV-1p256 and treated with increasing concentrations of flavopiridol. Supernatants were collected at 4, 8, 12 and 16 days post-infection. The amount of HIV-1 infection was measured by quantifying the amount of HIV-1 reverse transcriptase enzyme (RT) in the supernatants on the indicated days (BOTTOM graph for of each panel). Cytotoxicity studies were performed on uninfected PBLs by treating cells with increasing concentrations of flavopiridol for 4, 8, 12 and 16 days. Cell viability was estimated by performing ATPLite assay. The light readings were normalized to the mock treated cells and plotted (TOP graph for each panel).