The Influence of Erythrophagocytosis on the Interaction of Macrophages and Salmonella in Vitro

Phagocytosis and killing of Salmonella typhimurium by mouse peritoneal macrophages was inhibited when the bacteria and antibody-coated homologous erythrocytes or heterologous erythrocytes were simultaneously exposed to macrophages in vitro. No inhibition of phagocytosis or killing was observed in experiments employing uncoated or disrupted antibody-coated homologous erythrocytes. Degradation of S. typhimurium as measured by the loss of fluorescence from intracellular salmonella coated with fluorescein-labeled antibody was inhibited in macrophages which had previously ingested antibody-coated homologous erythrocytes. Anti-mouse-erythrocyte serum was found to have a cytotoxic action on mouse macrophages. However, the viability of macrophages was not altered by phagocytosis of antibody-coated homologous erythrocytes or uncoated heterologous erythrocytes.