FIG. 2.

CC/CXC chemokine inhibitions. (A) Bulk inhibition of the X (R5) panel of viruses with a high concentration of RANTES (200 nM) and of the X.10 (R5X4) panel of viruses with a high concentration of RANTES (200 nM) or SDF-1α (2 μg/ml). The experiments were performed with CD4⁺-enriched lymphocytes isolated from a CCR5^+/+ individual. The white bars represent percent inhibition by RANTES, and the black bars represent percent inhibition by SDF-1α. (B) Inhibition of the X and X.10 panels of viruses carrying the different V3 charges (symbols: diamonds, +3 V3 charge; squares, +4 V3 charge; triangles, +5 V3 charge; circles, +6 V3 charge) by RANTES and SDF-1α, respectively. (C) Inhibition of the +5 V3 viruses carrying the different glycosylation pattern (symbols: diamonds, X.10; squares, X.10ΔgV1; triangles, X.10ΔgV3). CD4⁺-enriched lymphocytes isolated from a CCR5^+/+ individual were used in the RANTES inhibition assays, while CD4⁺-enriched lymphocytes isolate from a CCR5^−/− individual were used in the SDF-1α inhibition experiments. The respective CD4⁺ lymphocytes (2.0 × 10⁵) were preincubated with serial dilutions of the chemokine for 1 h, and then the viruses were added. The day chosen for calculating inhibiting response was based on the day the p24 value of the positive control well peaked (not longer than 14 days), and percent inhibition was calculated by determining the reduction in p24 production in the presence of the agent compared to that for the cultures with virus only. For each inhibition experiment, a positive control, virus incubated with cells in the absence of the agent, and a negative control, virus in the absence of cells, was included. The negative control p24 concentration was subtracted from all of the test results. Each experiment was repeated at least twice with CD4⁺-enriched lymphocytes from different donors. Data are expressed as mean p24 values of triplicate wells, and the intersample SD did not exceed 10%.