Cross-protection against fecal excretion of Yersinia enterocolitica and Yersinia pseudotuberculosis in mice by oral vaccination of viable cells.

Mice given orally either the O3, O9, or O5B serovar of Yersinia enterocolitica showed protection upon subsequent oral challenge with another of these strains. Excretion of serovar O3 in the feces was inhibited in mice surviving oral challenge with Yersinia pseudotuberculosis IVA. Cross-reaction of O antigen among these four strains was 32 or more times lower than the homologous titers.