A comparison of the cytotoxic activity of eosinophils and other cells by 51 chromium release and time lapse microcinematography.

Antibody dependent cytotoxicity of chicken erythrocytes by purified rat eosinophils, neutrophils, macrophages and K cells has been compared by 51Cr release and time lapse microcinematography. Techniques have been developed for purifying these effector cell types. Both eosinophils and neutrophils cause rapid release of 51Cr from erythrocytes. Time lapse observations indicated that this was the result of phagocytosis. Eosinophils show rapid membrane movement and repeatedly engulf and regurgitate the erythrocytes. On the other hand, neutrophils become quiescent after phagocytosing erythrocytes, and remain quiescent until the remains of the cell are expelled. Neutrophils presumably have a mechanism for the release of soluble material, as 51Cr is released rapidly. Macrophages show a similar quiescence after phagocytosis, but in these cells there is apparently no rapid mechanism to expel material, as there is no significant 51Cr release over 20 h. K cells appear to damage chicken erythrocytes more slowly than they destroy tumour cells. Mast cells cause antibody-independent cytotoxicity which can be attributed to the release of toxic materials. None of these effector cells produced the type of lysis seen with antibody and complement.