The capsule encoding the viaB locus reduces interleukin-17 expression and mucosal innate responses in the bovine intestinal mucosa during infection with Salmonella enterica serotype Typhi

Infect Immun. 2007 Sep;75(9):4342-50. doi: 10.1128/IAI.01571-06. Epub 2007 Jun 25.

Abstract

The viaB locus contains genes for the biosynthesis and export of the Vi capsular antigen of Salmonella enterica serotype Typhi. Wild-type serotype Typhi induces less CXC chemokine production in tissue culture models than does an isogenic viaB mutant. Here we investigated the in vivo relevance of these observations by determining whether the presence of the viaB region prevents inflammation in two animal models of gastroenteritis. Unlike S. enterica serotype Typhimurium, serotype Typhi or a serotype Typhi viaB mutant did not elicit marked inflammatory changes in the streptomycin-pretreated mouse model. In contrast, infection of bovine ligated ileal loops with a serotype Typhi viaB mutant resulted in more fluid accumulation and higher expression of the chemokine growth-related oncogene alpha (GROalpha) and interleukin-17 (IL-17) than did infection with the serotype Typhi wild type. There was a marked upregulation of IL-17 expression in both the bovine ligated ileal loop model and the streptomycin-pretreated mouse model, suggesting that this cytokine is an important component of the inflammatory response to infection with Salmonella serotypes. Introduction of the cloned viaB region into serotype Typhimurium resulted in a significant reduction of GROalpha and IL-17 expression and in reduced fluid secretion. Our data support the idea that the viaB region plays a role in reducing intestinal inflammation in vivo.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Antigens, Bacterial / genetics
  • Antigens, Bacterial / physiology*
  • Bacterial Capsules / biosynthesis
  • Bacterial Capsules / genetics
  • Bacterial Capsules / immunology*
  • Cattle
  • Cell Movement / genetics
  • Cell Movement / immunology
  • Disease Models, Animal
  • Down-Regulation / genetics
  • Down-Regulation / immunology
  • Genetic Markers
  • Immunity, Mucosal* / genetics
  • Inflammation Mediators / metabolism
  • Inflammation Mediators / physiology
  • Interleukin-17 / antagonists & inhibitors*
  • Interleukin-17 / biosynthesis
  • Interleukin-17 / genetics
  • Intestinal Mucosa / immunology*
  • Intestinal Mucosa / microbiology*
  • Intestinal Mucosa / pathology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Neutrophils / immunology
  • Neutrophils / microbiology
  • Neutrophils / pathology
  • Operon / genetics
  • Polysaccharides, Bacterial / genetics
  • Polysaccharides, Bacterial / physiology*
  • Salmonella Infections, Animal / immunology*
  • Salmonella Infections, Animal / pathology
  • Salmonella Infections, Animal / prevention & control
  • Salmonella typhi / genetics*
  • Salmonella typhi / immunology

Substances

  • Antigens, Bacterial
  • Genetic Markers
  • Inflammation Mediators
  • Interleukin-17
  • Polysaccharides, Bacterial