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- Title
The Vi-capsule prevents Toll-like receptor 4 recognition of Salmonella.
- Authors
Wilson, R. Paul; Raffatellu, Manuela; Chessa, Daniela; Winter, Sebastian E.; Tükel, Çagla; Bäumler, Andreas J.
- Abstract
The viaB locus enables Salmonella enterica serotype Typhi to reduce Toll-like receptor (TLR) dependent cytokine production in tissue culture models. This DNA region contains genes involved in the regulation ( tviA), biosynthesis ( tviBCDE) and export ( vexABCDE) of the Vi capsule. Expression of the Vi capsule in S. Typhimurium, but not expression of the TviA regulatory protein, reduced tumour necrosis factor-alpha (TNF-α) and IL-6 production by murine bone-marrow derived macrophages. Production of TNF-α and IL-6 was dependent on expression of TLR4 as stimulation of macrophages from TLR4−/− mice with S. Typhimurium did not result in expression of these cytokines. Intraperitoneal infection of mice with S. Typhimurium induced expression of TNF-α and inducible nitric oxide synthase (iNOS) in the liver. Introduction of the cloned viaB region into S. Typhimurium reduced TNF-α and iNOS expression to levels observed after infection with a S. Typhimurium msbB mutant. In contrast, no differences in TNF-α expression between the S. Typhimurium wild type and strains expressing the Vi-capsule or carrying a mutation in msbB were observed after infection of TLR4−/− mice. We conclude that the Vi capsule prevents both in vitro and in vivo recognition of S. Typhimurium lipopolysaccharide by TLR4.
- Subjects
SALMONELLA; ENTEROBACTERIACEAE; FOOD pathogens; CYTOKINES; CELLULAR immunity; IMMUNOREGULATION; TUMORS; NITRIC oxide; NUCLEIC acids
- Publication
Cellular Microbiology, 2008, Vol 10, Issue 4, p876
- ISSN
1462-5814
- Publication type
Article
- DOI
10.1111/j.1462-5822.2007.01090.x