Complex arming in antibody-dependent cell-mediated cytotoxicity: ultrastructural studies of the interaction between human effector cells armed with aggregated anti-DNP antibody and DNP-coated erythrocytes.

We have examined, by transmission electron microscopy, mixtures of DNP-coated chicken red blood cells and normal human peripheral blood leucocytes 'armed' with alkali-aggregated anti-dinitrophenyl (DNP) antibody. The combination of these observations with chromium release assays enabled us to identify four types of effector cell interacting with the target erythrocytes, viz. phagocytic and non-phagocytic monocytes, neutrophils and lymphocytes. Comparison of these findings with previous work, using antibody-coated targets, allowed us to conclude that the mechanisms and cell types involved are similar. We also demonstrated the short-lived cytotoxic potential of cells armed in this manner.