Modulation of complement activity in vitro and in vivo by Yersinia wild and mutant strains.

The ability of released proteins (Yops) and surface lipopolysaccharides (LPS) from the wild-type strainYersinia enterocolitica 8081-L2, serotype O:8 to influence the complement activity was determined. Yops and LPS from wild-type and mutant strains showed different ability to affect the classical pathway (CP) functional complement activityin vitro. The serum CP activity was inhibited during the infection induced with sixY. enterocolitica and threeY. pseudotuberculosis strains in rabbits. The changed complement activity might be of importance for the course ofYersinia infections.