Detection of Antibody-Dependent Cell-Mediated Cytotoxicity—Supporting Antibodies by NK-92-CD16A Cell Externalization of CD107a: Recognition of Antibody Afucosylation and Assay Optimization

Antibody-dependent cell-mediated cytotoxicity (ADCC) by natural killer (NK) lymphocytes eliminates cells infected with viruses. Anti-viral ADCC requires three components: (1) antibody; (2) effector the Fc-IgG receptor CD16A; and (3) viral proteins in cell membranes. Fc-afucosylated antibodies bind greater affinity to CD16A than fucosylated antibodies; individuals’ variation afucosylation contributes differences ADCC. Current assays for afucosylated involve expensive methods. We report an improved bioassay that supports ADCC, which encompasses afucosylation. This assay utilizes externalization of CD107a NK-92-CD16A after antibody recognition. used anti-CD20 monoclonal antibodies, GA101 WT or glycoengineered (GE), 10% ~50% afucosylated, CD20-positive Raji target cells. increased detection 7-fold compared flow cytometry detect Raji-bound antibodies. GE effective concentrations (EC50s) differed 20-fold, GA101-GE more detectable. The EC50s vs. 51Cr death were similar blood NK Notably, % CD107a-positive negatively correlated dead nearly undetectable at high NK:Raji ratios required cytotoxicity. is very sensitive adaptable assess anti-viral but unsuitable as a surrogate monitor