The immunization of mice and calves with gal E mutants of Salmonella typhimurium.

A galactose epimeraseless (gal E) mutant of Salmonella typhimurium was investigated in mice and calves for its suitability as a live vaccine. In mice, a very highly significant difference in the mortality rates was observed when vaccinated and non-vaccinated animals were challenged with virulent strains of S. typhimurium and S. dublin. In calves, doses of 10(6) and above of gal E mutant injected subcutaneously provided highly significant protection both in terms of mortality and prevalence of symptoms when calves were challenged orally with S. typhimurium. However, there appeared to be a relation between the vaccine and the presence of renal lesions and before gal E mutants can be recommended, further work is necessary to determine the pathogenesis of these lesions.