FIG. 2.
PM1-M87 selection results in M87-resistant isolates with increased IC50 values for both the T-20 and T-649 fusion inhibitors. (A) Growth of wild-type HIV-1NL4-3 and HIV-1BaL in comparison to the PM1-M87-selected isolates NL/sel and BaL/sel in PM1 cells (left) and PM1-M87 cells (right). Target cells were infected at a multiplicity of infection of 0.01 and monitored over time for p24 antigen release into the supernatant. (B) TZM-bl cells were infected with 1,000 IU/well of the parental viruses (HIV-1NL4-3 and HIV-1BaL) and selected isolates (NL/sel and BaL/sel) in the presence of increasing concentrations of T-20 or T-649 (0.02 to 10 μg/ml). Firefly luciferase activity was measured 48 h postinfection and is plotted on the y axis as percent infection relative to the control infection without fusion inhibitor. Shown are the means of triplicate infections for each inhibitor concentration. These data were used to calculate IC50 values and the fold change of IC50 (see Table 1).