Figure 2.
R5 HIV replication is suppressed in total CD4 but not in purified M1 memory cells upon sufficient CD3/CD28 costimulation, and suppression does not correlate with CCR5 ligand secretion. CD4 T cell subsets were sorted as described in Fig. 1, infected with HIV-1BaL and stimulated with anti-CD3/B7 (50 ng/ml anti-CD3 plus either 0.2 or 2 fixed P815/B7 cells/T cell) or with anti-CD3/CD28 beads (0.3 or 3 beads/T cell). Supernatants and cells were harvested every 3 days for analysis of viral replication by RT activity (Top) and cell proliferation by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay (Middle); data are the average ± SD of triplicate cultures and are representative of 3–10 experiments. For some experiments, MIP-1α, MIP-1β, and RANTES levels were measured 6 days after stimulation and infection (Bottom).