DIFFERENTIAL PERSISTENCE, IMMUNOGENICITY AND PROTECTIVE CAPACITY OF TEMPERATURE-SENSITIVE MUTANTS OF SALMONELLA-ENTERITIDIS AFTER ORAL OR INTRAGASTRIC ADMINISTRATION TO MICE

The persistence of Salmonella enteritidis temperature-sensitive (ts) m utants of different phenotypes in Peyer's patches (PP) and the spleen, and their immunogenicity after intragastric (i.g.) and peroral (p.o.) administration to mice was investigated. After po. administration the ts mutant C/2/2 colonized PP, but was not recovered from the spleen. After i.g. administration the ts mutant E/1/3 colonized both the splee n and PP for at least 2 weeks. Mutant C/2/2 persisted in PP up to 8 da ys but was not found in the spleen. Mutant H/2/26, although it poorly colonized the PP, was recovered from the spleen up to day 15 after i.g . administration. Immunization with E/1/3 by either the i.g. or the p. o. routes protected mice from challenge with 100 LD50 of the virulent wild-type (wt) strain. Immunization with either C/2/2 or H/2/26 did no t confer protection. The three ts mutants induced the production of lo cal IgA after i.g. administration regardless of their protective capac ity.