FIG 5.

Primary viruses harboring a T375 residue are highly susceptible to ADCC responses mediated by HIV⁺ sera in the presence of CD4mc. Primary CD4⁺ T cells were infected with clade B primary HIV-1 and their variants (A to D) or with a panel of TF and chronic viruses from clades B and C (E to H). At 48 h postinfection, cell surface staining was performed with 10 different HIV⁺ sera. The graphs shown represent (A and E) the compiled mean fluorescence intensities (MFI) obtained with 10 HIV⁺ sera and (B and F) the fold increase in MFI in the presence of CD4mc calculated on the infected (p24⁺) population. Infected primary CD4⁺ T cells were also used as target cells, and autologous PBMCs were used as effector cells in a FACS-based ADCC assay. The graphs shown represent (C and G) the ADCC values and (D and H) the increases (in percentage points) in the levels of ADCC obtained in the presence of CD4mc with 10 HIV⁺ sera. These results were obtained in at least 2 independent experiments. Error bars indicate means ± SEM. Statistical significance was tested using a paired t test or a Wilcoxon signed-rank test (A to E and G) or an unpaired t test or Mann-Whitney U test (F and H), based on statistical normality (*, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001; ns, nonsignificant).