Experimental Salmonellosis

Abstract

When mononuclear phagocytes (macrophages), were infected with Salmonella enteritidis and confined in a diffusion chamber to incubate with normal macrophages, they confer on the normal macrophages cellular immunity, as detected by inhibition to intracellular multiplication of a virulent strain 116-54 and resistance to cellular degeneration caused by phagocytosis of bacteria. An immune ribonucleic acid (RNA) was extracted from the peritoneal macrophages maintained in tissue culture bottles in a homogeneous cell population which had been infected with strains of 5. enteritidis. When peritoneal macrophages, cultured in a homogeneous cell population, were treated in vitro with this agent, they developed cellular immunity and cellular antibody. The RNA preparation was not inactived by treatment with deoxyribonuclease, with pronase or with antibodies to a virulent strain 116-54 of S. enteritidis. These facts suggest that the macrophages constitute a cell line responsible for active antibody formation.