Antibody-dependent cell-mediated cytotoxicity (ADCC) of penicillin-treated human red blood cells

Penicillin-treated human red blood cells (RBC) were lysed by the cooperation of autologous nonsensitized peripheral blood mononuclear cells and human anti-penicillin serum. Using a rapid (3 h) assay of antibody-dependent cell-mediated cytotoxicity (ADCC), lysis was proportional to serum (anti-penicillin antibody) concentration, to incubation time and to the concentration of attacking cells, which were obtained from normal human peripheral blood by Ficoll-Hypaque separation. Incubation of these lymphoid effector cells on a nylon column prior to the tests depleted the number of phagocytic (latex positive) cells in the effluent; there was a concomitant drop in cytotoxic activity. Enrichment of mononuclear phagocytes in the attacking cell population by albumin gradient separation led to an increase in cytotoxicity. Granulocytes separated by Ficoll-Hypaque were not active in this system. Using specific antisera the antibody was found to be of the IgG1 sub-class. Anti-penicillin antibody activated the complement system in vitro, but failed to induce lysis of penicillin-treated RBC in the presence of complement without attacking cells. These results suggest that ADCC may participate in the destruction of RBC in penicillin-induced haemolysis in vivo.