Fig. 5.

1E5-IgG3 induces higher ADCC than 1E5-IgG1 in the presence of anti-CoRBS antibody and CD4mc. The ability of IgG1 and IgG3 forms of 1E5 to mediate signaling through FcγRIIIa when bound to cells expressing Env is shown. HEK 293T cells transfected with HIV-1 Env (nine binding assay positive Env proteins from a CRF02_AG panel) were incubated with the indicated antibodies and the ADCC indicator cell line expressing FcγRIIIa. Simultaneous binding of antigen and FcγRIIIa results in activation of the NFAT transcription factor, which induces luciferase in indicator cells. IE5 was used (10 µg/ml) alone or in combination with 4E9C (5 µg/ml) and CD4mc YIR-821 (20 µM). The fold change was calculated by dividing the luminescence units in the presence of Ab with those in the absence of Ab. NHG was used as a control. a ADCC activity against each target cell is shown. Experiments were performed in triplicate, and the means ± standard errors of the means are shown. b ADCC activity against target cells expressing Env from nine CRF02_AG strains was plotted, and statistically analyzed. The means ± standard errors of the means are shown. Statistical significance was tested using a paired t test (*, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001; ns, non-significant)