<I>In vivo</I> Tolerance to Lipopolyssacharides of Vaccine and Virulent <I>Yersinia pestis</I> Strains
The endotoxin tolerance phenomenon has been reproduced in vivo. Different forms of lipopolysaccharide (LPS) of vaccine (EV 76) and virulent (231) Y. pestis strains, grown at 28 and 37 °C, and LPS of S- and R-chemotypes of Escherichia coli were injected to the white mice in different combinations. Determined is the fact that primary and repeated injection of plague microbe LPS preparations in any combinations results in suppression of inflammatory response regardless of the differences in the LPS structure. In case of combined administration of Y. pestis LPS and E. coli LPS, the response depends on the LPS form and can vary from complete or partial tolerance to its total absence.