Cross-protection aginst Salmonella enteritidis infection in mice. I. Immunization trials.

Mice were immunized subcutaneously with live and killed vaccines, with and without complete adjuvant incorporating Salmonella typhi-murium M206, Salmonella gallinarum 9R, Salmonella pullorum Sp223 as well as homologous Salmonella enteritidis Se795. The animals were challenged 21 days post-vaccination with 100 LD50 of virulent S. enteritidis 5694 SMR subcutaneously along with unvaccinated control mice. To assess the immunity against acute and chronic infections, the percentage of absolute survivors i.e. survivors without lesions and without the challenge organism, was taken as the criterion. Live vaccines proved better than killed vaccines. Live vaccines with complete adjuvant induced a good protection. Cross-protection could be induced with the live vaccine with complete adjuvant against S. enteritidis infection in mice.