FIG 3.
Fc glycosylation profile of PGT121 regulates its ADCC capacity against infected cells. CEM.NKR-CCR5-sLTR-Luc cells infected with HIV-1JRCSF (A), SHIVBG505 (B), and SHIVAD8-EO (C) were used as target cells. PBMCs from uninfected donors were used as effector cells in a FACS-based ADCC assay. The graphs shown represent the percentages of ADCC obtained in the presence of the respective antibodies. (D and E) For the luciferase assay, CEM.NKr-CCR5-sLTR-Luc cells infected with SHIVAD8-EO, or SIVmac239 as a negative control. ADCC responses were measured as the dose-dependent loss of luciferase activity in RLU after incubation of infected CEM.NKR-CCR5-sLTR-Luc cells with CD16+ KHYG-1 effector cells in the presence of antibody. Values are the means ± standard deviations (error bars) for triplicate wells, and the dotted line indicates half-maximal lysis of infected cells. (E) Area under the curve (AUC) values were calculated using from curves of increasing MAb concentrations shown in panel D. Error bars indicate means ± the SEM. 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). Black histogram bars represent 293F cell-derived MAbs and green histogram bars represent plant-derived MAbs.