Temperature-modulated immunogenicity to Yersinia pestis from Yersinia enterocolitica O3

The ability of Yersinia enterocolitica O3, grown at 25 degrees C, to promote cross-immunity to Y. pestis was lost after repeated subcultures at 37 degrees C, which selected for bacterial populations having lower in vivo survival. Subculturing Y. enterocolitica O3 from 37 to 25 degrees C restored the cross-immunogenicity although the in vivo survival remained low.