FIG 5.

Susceptibility of ex vivo-expanded endogenously infected primary CD4⁺ T cells from HIV-1-infected individuals to PGT121-mediated ADCC. Primary CD4⁺ T cells from four different HIV-1-infected individuals were isolated and reactivated with PHA-L for 48 h, followed by incubation with IL-2 to expand the endogenous virus. Cell surface staining of infected primary CD4⁺ T cells was performed upon reactivation. Antibody binding was detected either by using Alexa Fluor 647-conjugated anti-human secondary Abs (A) or biotin-tagged dimeric rsFcγRIIIa (0.2 μg/ml) followed by the addition of Alexa Fluor 647-conjugated streptavidin (B). (A and B) Graphs represent the MFI values in the infected population (p24+ or p27+) determined from at four different donors, with the error bars indicating means ± the SEM. (C) Ex vivo-expanded infected primary CD4⁺ T cells from three HIV-1-infected individuals were used as target cells. Autologous PBMCs were used as effector cells in a FACS-based ADCC assay. The graphs represent the percentages of ADCC obtained in the presence of the respective antibodies. ADCC susceptibility was only measured when the percentage of infection (p24+ cells) was higher than 10%. Statistical significance was tested using a paired t test or Wilcoxon matched-pairs signed-rank test based on statistical normality (*, P < 0.05; **, P < 0.01; ***, P < 0.001; ns, nonsignificant). Black histogram bars represent 293F cell-derived MAbs, and green histogram bars represent plant-derived MAbs.