title: The Salmonella typhimurium AhpC polypeptide is not essential for virulence in BALB/c mice but is recognized as an antigen during infection.
abstract: The OxyR regulon is known to mediate protection against oxidizing agents in Salmonella typhimurium. We reported previously that ahp, one of the OxyR-regulated loci, is induced during macrophage interaction (K. P. Francis, P. D. Taylor, C. J. Inchley, and M. P. Gallagher, J. Bacteriol. 179:4046-4048, 1997). We now report on the effects of disrupting ahp or oxyR on virulence in a BALB/c mouse model. Surprisingly, insertion of a Mudlux derivative within ahpC was found to result in attenuation, while irreversible inactivation of the locus through insertion of a cml cassette did not. An SL1344 derivative carrying an oxyR::kan disruption was also found to be as virulent as the parental strain. Moreover, both cell-mediated and humoral responses to AhpC were found to develop during the course of infection, probably through T-helper-cell (type I) activation. These results indicate that, although not essential for virulence, AhpC is expressed by S. typhimurium during infection of BALB/c mice and constitutes a target for the immune system.
authors.affiliation: Division of Biology, University of Edinburgh, Edinburgh EH9 3JR, Scotland, United Kingdom.
authors.forename: P D
authors.initials: PD
authors.lastname: Taylor
authors.forename: C J
authors.initials: CJ
authors.lastname: Inchley
authors.forename: M P
authors.initials: MP
authors.lastname: Gallagher
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000502:physiology*; D004268:DNA-Binding Proteins; D005260:Female; D007156:Immunologic Memory; D051379:Mice; D008807:Mice, Inbred BALB C; D010088:Oxidoreductases / Q000502:physiology*; D010544:Peroxidases; D054464:Peroxiredoxins; D012097:Repressor Proteins / Q000502:physiology; D012481:Salmonella Infections, Animal / Q000276:immunology*; D012486:Salmonella typhimurium / Q000276:immunology* / Q000472:pathogenicity; D013601:T-Lymphocytes / Q000276:immunology; D014157:Transcription Factors / Q000502:physiology; D014774:Virulence
chemical_list: D000942:Antigens, Bacterial; D004268:DNA-Binding Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D010088:Oxidoreductases; D010544:Peroxidases; D054464:Peroxiredoxins