Electron microscopic studies on the peritoneal exudate of the mouse to determine the effect of colloidal carbon on the primary immune response to heterologous erythrocytes]

Antibody production to sheep erythrocytes was markedly depressed in mice injected intraperitoneally with colloidal carbon. Peritoneal exudate cells were investigated electron microscopically with regard to mechanisms responsible for lower antibody production. Peritoneal macrophages were not disturbed in antigen phagocytosis and antigen digestion. Only in connection with immunosuppression was there an increase in antigen containing macrophages in the peritoneal cavity. The changing relation of antigen-stimulated macrophages and lymphocytes in favour of the macrophages and its consequence to decreased immune response is discussed.