FIG 3.

The Phe 43 cavity modulates ADCC responses mediated by the A32 antibody and antibodies within HIV⁺ sera. Primary CD4⁺ T cells infected with NL4.3-GFP expressing the primary R5 ADA Env (clade B) or SHIV expressing either CH505 (clade C) or 191859 (clade D) Env were used as target cells and autologous PBMCs were used as effector cells in our FACS-based ADCC assay, as described in Materials and Methods. Shown are the percentages of ADCC activity in the presence of anti-cluster A monoclonal antibody A32 (A to C) or in the presence of HIV⁺ sera from HIV-1 clade B-infected individuals (D to F). These results are representative of those obtained in at least 3 independent experiments. Error bars indicate means ± standard errors of the means. Statistical significance was tested by using paired one-way analysis of variance with a Holm-Sidak posttest (*, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001; ns, nonsignificant).