Comparison of the abilities of Salmonella typhimurium rpoS, aroA and rpoS aroA strains to elicit humoral immune responses in BALB/c mice and to cause lethal infection in athymic BALB/c mice

• Published in: Microbial pathogenesis Vol. 26; no. 6; pp. 299 - 305
• Main Authors: COYNAULT, C, NOREL, F
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier 01.06.1999
• Subjects: 3-Phosphoshikimate 1-Carboxyvinyltransferase; Alkyl and Aryl Transferases - immunology; Animals; Antibody Formation; aroA gene; Bacterial Proteins - immunology; Bacterial Vaccines - immunology; Bacteriology; Biological and medical sciences; Female; Fundamental and applied biological sciences. Psychology; Lipopolysaccharides - immunology; Mice; Mice, Inbred BALB C; Mice, Nude; Microbiology; rpoS gene; Salmonella typhimurium; Salmonella typhimurium - immunology; Serotyping; Sigma Factor - immunology; Vaccination; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies; Vaccines, Synthetic - immunology; Immunoprotection; Rodentia; Vaccine; Salmonella typhimurium; Pathogenicity; Vertebrata; Mammalia; Immunogenicity; Mouse; Initiation factor σ; Bacteria; Mutation; Attenuated strain; Humoral immunity; Enterobacteriaceae
• ISSN: 0882-4010; 1096-1208
• DOI: 10.1006/mpat.1999.0273

Salmonella typhimurium rpoS and rpoS aroA mutants are effective live vaccines in the murine model of salmonellosis (Coynault et al., Mol. Microbiol. 1996; 22: 149-60). Here, we further investigate the characteristics of these vaccines. The systemic humoral response induced by S. typhimurium rpoS, aroA and rpoS aroA vaccine candidates against S. typhimurium LPS was studied by ELISA. In BALB/c mice, the rpoS aroA strain induced a systemic anti-LPS humoral response similar to that induced by the rpoS and aroA strains. The virulence of aroA and rpoS aroA vaccines in nude (nu/nu) BALB/c mice was also compared. Salmonella typhimurium aroA and rpoS aroA vaccines both produced slowly progressing lethal infections in athymic mice inoculated i.p. but the rpoS aroA strain was more attenuated than the aroA strain, as determined by time to death and bacterial counts in spleens. Finally, a rpoS mutant of Salmonella dublin conferred protection in mice against an oral challenge with a wild-type strain of S. dublin whereas a rpoS mutant of S. typhimurium did not. This suggests that the protection provided by the S. typhimurium rpoS vaccine is serotype-dependent.