FIG 3.

Exogenously added dT, but not dC, affects AZT and d4T potencies. TZM-bl cells were treated with PBS, 100 μM dT, or 100 μM dC or 100 µM dA (as controls for noncompeting nucleosides) and infected with HIV-1_NL4-3 at an MOI of 0.02, in the presence of increasing concentrations of inhibitor (AZT or d4T). At 48 h postinfection, cells were lysed and luciferase activity was detected. Luciferase activity at various drug concentrations was plotted using the one-site competition equation in GraphPad Prism 5, and data were normalized to the no-nucleoside control results. Data represent the mean ± SD from at least three independent experiments. Data in the table represent the mean ± SD from at least three independent experiments. Shown also are the fold changes in the EC₅₀ of NRTI in the presence or absence of cognate nucleoside, which indicate change in sensitivity to AZT/d4T, 3TC, or ddI, in the presence of dT, dC, or dA, respectively. ND, not determined.