Lysis of alloantibody-sensitized human erythrocytes by peripheral blood mononuclear cells: heterogeneity of effector populations.

Cell-mediated haemolysis of human erythrocytes (HRBC) mediated by sensitizing alloantibodies of two specificities was studied using the 51Cr release assay. Peripheral blood mononuclear cells (PBMC) were found capable fo lysing HRBC of phenotype ARh(D) + ve sensitized with either anti-D or "natural" anti-A antibodies. The characteristics of the effector population, however, were dependent upon the sensitizing antibody. HRBC sensitized with anti-A were lysed by a radioresistant, silica- and carrageenan-sensitive population which could be selectively removed by adherence. Sensitization with rhesus antibody induced cytotoxicity by a population which was radiosensitive and relatively unaffected by removal of adherent cells or by treatment with silica or carrageenan. The results demonstrate that the antigen-antibody interaction, rather than the target cell type, determines which effector cells participate in antibody-dependent cellular cytotoxicity (ADCC) against human red cells.