[Phenotypic variability of the causative agent of pseudotuberculosis and its reflection in the immune response]

The avirulent rough form of Y. pseudotuberculosis has been shown to be a weak antigen, not stimulating antibody formation, quickly destroyed in phagocytes and possessing no immunogenic properties. The virulent bacteria in the smooth form multiply in macrophages and polymorphonuclear leukocytes, sharply suppress phagocytosis, stimulate the synthesis of IgM and IgG and possess low immunogenicity. The pseudorough form of Y. pseudotuberculosis quickly spreads in the organs and tissues, is destroyed by phagocytes, stimulates only the synthesis of IgM and produces a good protective effect.