Figure 4. Reduced binding of HIV-specific antibodies to T_CD32^dim cells and the effect on natural killer (NK) degranulation.

The binding capability of the HIVgp120-specific IgG A32, an antibody (Ab) labeled with allophycocyanin (APC), to gp120-coated T_CD32^dim and T_CD32⁻ cells from healthy donors, before and after incubation with plasma containing non-HIV specific IgGs, was measured by flow cytometry (n=7). Percentage of the Mean Fluorescence Intensity (MFI) signal, normalized to the medium, for A32⁺ cells after plasma addition is shown in (A) Representative histogram of A32⁺ T_CD32^dim cells, (B) T_CD32^dim and (C) T_CD32⁻ cells. (D) Percentage of cell conjugates between ex vivo HIV-infected T_CD32^dim or T_CD32⁻ and NK cells after performing antibody-dependent cell cytotoxicity (ADCC) assays (n=14). (E) Percentage of NK degranulation (CD107a marker) in cell conjugates with sorted T_CD32^dim or T_CD32⁻-coated with gp120 HIV protein and incubated with plasma HIV⁺, after a 4 hr antibody-dependent cell cytotoxicity (ADCC) activation assay (n=3). Values are normalized to the CD32 population (F) Schematic illustration of the impaired ADCC response against T_CD32^dim cells. Graphs show median with range and statistical comparisons were performed using Wilcoxon matched-pairs signed-rank test. *p<0.05.

Figure 4—figure supplement 1. Binding of A32 to T cells and percentage of IFN-γ in cell conjugates.

The binding capability of the A32 HIV-specific antibody (APC-labeled) to gp120-coated T_CD32^dim and T_CD32⁻ before and after incubation with plasma containing non-HIV-specific IgGs, was measured by flow cytometry. (A) Percentage of A32⁺ T_CD32^dim cells. (B) Percentage of A32⁺ T_CD32⁻ cells. (C) Percentage of IFN-γ⁺ NK cells in cell conjugates with sorted T_CD32^dim and T_CD32⁻ cells after ADCC assays. Statistical comparisons were performed using the Wilcoxon matched-pairs signed-rank test.supplementary information.