Salmonella enteritidis temperature-sensitive mutants protect mice against challenge with virulent Salmonella strains of different serotypes

The protection conferred by temperature-sensitive mutants of Salmonella ent eritidis against different wild-type Salmonella serotypes was investigated. Oral immunization with the single temperature-sensitive mutant E/1/3 or wi th a temperature-sensitive thymine-requiring double mutant (E/1/3T) conferr ed: (i) significant protection against the homologous wild-type Salmonella strains; (ii) significant cross-protection toward high challenge doses of S . typhimurium. Significant antibody levels against homologous lipopolysacch aride and against homologous and heterologous protein antigens were detecte d in sera from immunized mice. Moreover, a wide range of protein antigens f rom different Salmonella O serotypes were recognized by sera from immunized animals. Besides, primed lymphocytes from E/1/3 immunized mice recognized Salmonella antigens from different serotypes. Taken together, these results indicate that temperature-sensitive mutants of S. enteritidis are good can didates for the construction of live vaccines against Salmonella. (C) 2000 Federation of European Microbiological Societies. Published by Elsevier Sci ence B.V. All rights reserved.