Identification of the predominant human NK cell effector subset mediating ADCC against HIV-infected targets coated with BNAbs or plasma from PLWH.

The potential of immunotherapy strategies utilizing broadly neutralizing antibodies (BNAbs), such as 3BNC117 and 10-1074, to limit viral replication while also facilitating clearance of HIV infected cells has heightened interest in identifying the predominant NK effector subset(s) capable of mediating antibody dependent cellular cytotoxicity (ADCC). Utilizing advanced polychromatic flow cytometry, we identified that CD57 positive NK cells from ART-suppressed in People Living With HIV (PLWH) expressed significantly higher levels of the CD16 FcγR receptor, 2B4 ADCC coreceptor, and HLA-DR activation marker while NKG2C positive NK cells expressed significantly higher levels of the CD2 ADCC coreceptor (p < 0.001, n = 32). Functionally, CD57 positive NK cells from ART-suppressed PLWH with either high or low NKG2C expansion exhibited significantly enhanced degranulation and IFN-γ production against heterologous gp120-coated ADCC targets coated with HIV reference plasma compared to CD57 negative NK cells (p = 0.0029, n = 11). CD57 positive NK cells from control donors lacking NKG2C expansion also exhibited significantly more degranulation and IFN-γ production at every timepoint tested against both heterologous ADCC targets (p = 0.019, n = 9) and HIV-1 infected autologous CD4+ primary T cells coated with BNAbs. Together, our data support CD57 positive and NKG2C positive NK cells as the predominant ADCC effector subsets capable of targeting HIV-infected CD4+ cells in the presence of 3BNC117 and 10-1074 immunotherapy.