[The significance of pesticin 1 for the virulence and immunogenicity of Yersinia pestis].

The work deals with the study of the virulent and immunogenic properties of Y. pestis strains which lost their capacity for producing pesticine 1 as the result of the insertion of a Tn-like element into the 6-MD plasmid responsible for this property. The "switching-off" of gene pst induced a decrease in the virulence of Y. pestis injected subcutaneously into white mice and guinea pigs and had no influence on its level of immunogenicity for white mice. A suggestion was made that pesticine 1 played no essential role in the expression of the virulence and immunogenicity of Y. pestis penetrating into the body by subcutaneous route.