FIG. 1.

Dose-response curves for inhibition of HIV-1_JR-FL envelope-mediated membrane fusion by combinations of CCR5 inhibitors. Dilutions were analyzed in triplicate wells, and the data points depict the means and standard deviations of replicates. (A) PRO 140 and maraviroc (UK-427,857) were tested individually and in a 1:1 fixed molar ratio over the indicated range of concentrations. In the experiment whose results are depicted, IC₅₀ and IC₉₀ values were 2.9 nM and 11 nM for PRO 140, 5.0 nM and 21 nM for maraviroc, and 2.1 nM and 4.6 nM for the combination, respectively. CI₅₀ and CI₉₀ values were 0.58 and 0.32, respectively. (B) Vicriviroc (SCH-D) and maraviroc were tested individually and in a 1:1 fixed molar ratio over the indicated range of concentrations. In the experiment whose results are depicted, IC₅₀ and IC₉₀ values were 5.5 nM and 34 nM for vicriviroc, 9.7 nM and 59 nM for maraviroc, and 6.1 nM and 31 nM for the combination, respectively. CI₅₀ and CI₉₀ values were 0.87 and 0.73, respectively.