[The pathogenic properties of the causative agent and the immunological indices in an experimental Yersinia infection].

In experiments on guinea pigs infected enterally with Y. enterocolitica isogenic strains of serovar O3 (pYV+ and pYV-) with known properties some characteristics of their cell-mediated and humoral immunity and nonspecific resistance were studied. The development of the localized infectious process and the corresponding immune shifts were noted only in infection with plasmid-containing Yersinia; in these cases a rise in the amount of T- and B-lymphocytes in the immunocompetent organs (the thymus, the spleen, lymph nodes), an increase in the functional activity of T-lymphocytes, a decrease in the ingestive activity of neutrophils and in the levels of nonenzymatic cation proteins and leukocytes, as well as the active production of specific agglutinins, were registered.