FIG. 2.

VacA inhibits HIV infection of IL-2-dependent TCR-activated and cytokine-stimulated primary T cells. (A) Resting primary human CD4⁺ T cells were TCR/CD28 activated, and cells were then expanded in the presence of IL-2 (yielding “preactivated” cells). After 7 days, cells were removed from IL-2 and treated with VacA, AZT, rapamycin (Rap), CsA, or VacAΔ6-27 for 8 h. Concentrations of these agents were as described in Materials and Methods. Cells were then washed, restimulated with IL-2, and infected with HIV.VSVG (A) or HIV.R5 (B) in the presence of the indicated additives. (C and D) Cytokine-stimulated CD4⁺ T cells (cultured in IL-2-containing medium for 7 days in the absence of TCR stimulation) were pretreated with the indicated additives for 8 h and then washed and infected with either HIV.VSVG (C) or HIV.R5 (D) in the presence of the indicated additives. Infection was assessed by analyzing GFP expression using flow cytometry at 72 h. Results are representative of three experiments performed in triplicate with T cells isolated from different donors. Asterisks indicate P < 0.05 compared to PBS-treated cells at the same time point. Statistical significance between groups was determined by a two-tailed t test.