[The effect of a plague pathogen plasmid on lethality and immunogenicity].

On the model of Yersinia transconjugants (Yersinia pestis, Yersinia pseudotuberculosis, Yersinia enterocolitica) carrying the conjugative cointegrates containing the 47 and 65 Md plasmids from Yersinia pestis the data were obtained on the different affects of the latter plasmids on the lethality and immunogenicity conferred by the host bacterial cells. The plasmid effects were drastically different during bacterial infection in mice or guinea pigs. The possibility of appearance of the recombinant Yersinia in natural epizootic foci of plague and suggestions on their regulating role are discussed.