Bispecific anti-human red blood Rhesus-D antigen × anti FcγRI targeted antibody-dependent cell-mediated cytotoxicity and phagocytosis by mononuclear leucocytes

Abstract

SUMMARY The Fc receptor mediated antibody-dependent cell-mediated cytotoxicity (ADCC) and phagocytosis induced by bispecific antibody (BsAb) to the high-affinity Fc receptor for IgG (FcγRI) and to human red blood group antigen RhD were studied in vitro, using human mononuclear leucocytes as effector cells. The results were compared with those obtained by using a human monoclonal IgGI anti-RhD used alone and a reference human polyclonal anti-RhD antibody. The effect of non-specific human IgG on FcR-mediated functions by mononuclear leucocytes was checked. The results demonstrate that BsAb presents a high resistance of Fc-mediated function to blockade by non-specific human IgG compared with that of both polyclonal and monoclonal anti-RhD antibodies. These results further encourage possible clinical application of bispecfic antibody in passive immunotherapy.