ADCC against human erythrocyte target cells: role of the anti-target cell antibodies in determining lymphocyte killer activity.

Studies were undertaken to investigate the role of anti-target cell antibodies in determining whether lymphocytes can mediate antibody-dependent cellular cytotoxicity (ADCC) in vitro. Trinitrophenyl (TNP) modified Chang liver cells and human erythrocytes were employed as target cells and were coated with xenogeneic and allogeneic antibodies against TNP and natural cell surface antigens. Two cytotoxic effector cell populations were used: human peripheral blood mononuclear cells (PBMC) containing both lymphocytes and monocytes, and monocyte-depleted peripheral blood lymphocytes (PBL). With Chang targets, both PBMC and PBL mediated ADCC with xenogeneic anti-Chang and xenogeneic anti-TNP sera. With human erythrocyte targets, PBMC but not PBL mediated ADCC with human anti-blood group B serum, while both PBMC and PBL mediated ADCC with xenogeneic anti-TNP sera and also with a human anti-CD serum. These results demonstrate that the source of anti-target cell antibodies employed in ADCC reactions may determine whether or not lymphocytes are capable of mediating cytotoxicity.