(A) ADCC assays similar to those described in Fig 1. CEM.NKR-CCR5-LTR-Luc target cells were infected for 3 days with YU2. Effector cells were added at a 10:1 ratio in the presence of 3-fold serial dilutions beginning at 1:32 dilution of human sera from uninfected or HIV-1 positive patients alone (red) or in the presence of 1 μg/mL eCD4-IgG2 (blue), VRC01-IgG2 (green), or 10-1074-IgG2 (purple). ADCC activity was determined by luciferase activity after an 8 hour incubation. (B) ADCC activity of eCD4-IgG1, eCD4-IgG2, VRC01-IgG2, and 10-1074-IgG2 was measured in a similar manner as in (A). Results are represented as means +/- S.E.M. (n = 3). Data are representative of at least two independent experiments. (C) 50% ADCC titers were calculated from curves in (A) as the dilution at which lines crossed the 50% maximal luciferase value. Paired t-test, ***p<0.001. (D) ADCC assay similar to those described in A. In this case, ADCC activity of serum 9121658 was tested alone (red) and in combination with 1 μg/mL eCD4-IgG1 (light blue), eCD4-IgG2 (dark blue), or CD4-IgG2 (burgundy).