Figure 4

Relative efficiencies of CD4 and CCR5 usage by MVC-Sens and MVC-Res Envs as assessed by the 293-Affinofile receptor affinity profiling system. 293-Affinofile cells were induced by minocycline and/or ponasterone A to express 25 different combinations of CD4 and CCR5 expression levels and then infected by equal amounts (10 ng of Gag p24) of MVC-Sens or MVC-Res in the presence or in the absence of 10 μM MVC. Thirty hours post-infection, luciferase activity was measured in the cell lysates and the three metrics θ (a), M (b) and Δ (c) describing viral infectivity were then determined using the VERSA website (http://versa.biomath.ucla.edu). The maximally induced levels of CD4 and CCR5 were 287,000 and 83,000 receptor/cell. Results represent the mean ± SE of at least four independent determinations. *P < 0.05 in unpaired two-tailed Student t test.