[Interaction of the causative agent of pseudotuberculosis with the peritoneal macrophages from an immune and a nonimmune organism].

The role of phagocytosis in experimental pseudotuberculosis was demonstrated in vivo and in vitro. Virulent Y. pseudotuberculosis strain caused the death of the majority of the cells, whereas the weakly-virulent ones--degenerative changes and the death of but of few of them. The capacity of the causative agents of pseudotuberculosis to survive and to reproduce within the cells could be regarded as one of the significant factors of virulence of these microbes. The maximal immunizing effect was observed in infection of the animals with sublethal dose of the living Y. pseudotuberculosis culture. A somewhat lesser, but a sufficiently high, immunizing effect was produced by lipopolysaccharide. A method of macrophage culture can be used for the assessment of the immunogenicity of various antigenic complexes of the microbes.