Immunological analysis of the plasmid-encoded proteins from the highly pathogenic Yersinia enterocolitica serogroup O8 and the less pathogenic serogroup O3.

The plasmid-encoded proteins of the pathogenic Yersinia enterocolitica serogroups O3 and O8 were analysed with respect to their immunological relationship. Common epitopes on yersinia outer-membrane proteins (YOPs) and released proteins (RPs) were recognised by orally-induced antisera against living bacteria and by monospecific antisera induced against single RPs of Y. enterocolitica serogroup O8. A major difference between the pathogenic serogroups O3 and O8 was YOP42, which was detected only in the outer membrane of the highly pathogenic O8+ bacteria. The YOP42 may be responsible for the greater virulence of serogroup O8 bacteria.