FIG 6.

Sensitivity or binding of Env-A539V to NAbs recognizing different Env conformations, anti-CD4 Ab, and coreceptor antagonist. TZM-bl cells were exposed to 100 TCID₅₀ of WT NL4-3 or Env-A539V viruses in the presence of various concentrations of NAbs (A to J), anti-CD4 Ab (K), and CXCR4 antagonist (L); luciferase activity was measured at 48 h postinfection. Data from three independent experiments are shown as means ± SEs. 293T cells transfected with the green fluorescent protein (GFP)-encoding reporter clone pBR43IeG expressing WT NL4-3 Env or the Env-A539V mutant were preincubated with 17b (M), 10E8 (N), PG16 (O), or PGT145 (P) at 4°C for 1 h. KFS is an Env-defective mutant. The cells were washed, and APC-conjugated anti-human IgG was used to detect bound Ab. APC signals were normalized by GFP signal to calculate the Ab binding efficiency. Data are shown as means ± SEs from three independent experiments. ***, P < 0.001; **, P < 0.01; *, P < 0.05 by unpaired t test or one-way ANOVA and Tukey’s multiple-comparison test.