FIG. 2.

IC₅₀ values for five NRTIs in P4 cells and in MDMs infected with WT NL4-3. HeLa P4 cells (10⁴ cells in 96-well microtiter plates) were pretreated with different drugs for 4 h and then infected with 8 ng of WT NL4-3ΔenvΔNef-Luc⁺/VSV-G virus p24/ml. MDMs (10⁵ cells in 96-well microtiter plates) were pretreated with the same NRTIs at the time of infection (0 h) or for 4 or 16 h prior to infection with 80 ng/ml p24 of WT NL4-3ΔenvΔNef-Luc⁺/VSV-G-pseudotyped virus. Infection was monitored by quantifying the luciferase activity 40 h postinfection in P4 cells and 72 h postinfection in MDMs. The experiments presented here were performed with MDMs from at least three different independent donors tested in independent experiments and represent the means of quadruplicate cultures for each donor. Each point represents the mean of quadruplicate cultures of cells from a single donor. Graphs report the IC₅₀ values measured for AZT (A), d4T (B), ddI (C), 3TC (D), and TDF (E). The differences in mean IC₅₀ measured for each drug in HeLa P4 tumor cells and in MDMs pretreated with the NRTIs for different times were compared by using a one-way ANOVA test, followed by a Bonferroni's multiple-comparison post-test comparing the p4 IC₅₀ to each of the IC₅₀s measured in MDMs for each pretreatment length when differences between groups were significant. When significant, the P values are reported on the graph.