Antibody‐Dependent Monocyte‐Mediated Cytotoxicity

Among mononuclear cells isolated from human blood monocytes exclusively mediated antibody‐dependent cytolysis of human type B erythrocytes. Adherent monocytes detached from plastic surfaces by lowering the temperature to 4°C expressed the same cytotoxicity as monocytes contained in the unseparated mononuclear cell fractions. No difference was observed in the cytotoxicity of non‐adherent monocytes and of monocytes remaining adherent at 4°C and subsequently mechanically removed. Removal of carbonyl‐iron phagocytosing monocytes reduced the number of latex‐phagocytosing monocytes without influencing cytotoxicity of the remaining monocytes. In vitro cultivation for 24h of unseparated mononuclear cells and of purified monocyte suspensions increased the number of latex‐positive cells, leaving the number of esterase‐positive cells and the cytotoxicity unchanged.