A Phase-Variable Capsule Is Involved in Virulence of Campylobacter Jejuni 81-176

Mol Microbiol. 2001 May;40(3):769-77. doi: 10.1046/j.1365-2958.2001.02431.x.

Abstract

Campylobacter jejuni strain 81-176 (HS36, 23) synthesizes two distinct glycan structures, as visualized by immunoblotting of proteinase K-digested whole-cell preparations. A site-specific insertional mutant in the kpsM gene results in loss of expression of a high-molecular-weight (HMW) glycan (apparent Mr 26 kDa to > 85 kDa) and increased resolution of a second ladder-like glycan (apparent Mr 26-50 kDa). The kpsM mutant of 81-176 is no longer typeable in either HS23 or HS36 antisera, indicating that the HMW glycan structure is the serodeterminant of HS23 and HS36. Both the kpsM-dependent HMW glycan and the kpsM-independent ladder-like structure appear to be capsular in nature, as both are attached to phospholipid rather than lipid A. Additionally, the 81-176 kpsM gene can complement a deletion in Escherichia coli kpsM, allowing the expression of an alpha2,8 polysialic acid capsule in E. coli. Loss of the HMW glycan in 81-176 kpsM also increases the surface hydrophobicity and serum sensitivity of the bacterium. The kpsM mutant is also significantly reduced in invasion of INT407 cells and reduced in virulence in a ferret diarrhoeal disease model. The expression of the kpsM-dependent capsule undergoes phase variation at a high frequency.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • ATP-Binding Cassette Transporters*
  • Bacterial Capsules / metabolism
  • Bacterial Capsules / physiology*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Bacterial Proteins / physiology
  • Campylobacter jejuni / genetics
  • Campylobacter jejuni / metabolism
  • Campylobacter jejuni / pathogenicity*
  • Cloning, Molecular
  • Escherichia coli / genetics
  • Escherichia coli Proteins*
  • Genetic Complementation Test
  • Lipid Metabolism
  • Membrane Transport Proteins*
  • Mutagenesis
  • Polysaccharides / metabolism
  • Sequence Analysis, DNA
  • Virulence

Substances

  • ATP-Binding Cassette Transporters
  • Bacterial Proteins
  • Escherichia coli Proteins
  • Membrane Transport Proteins
  • Polysaccharides
  • kpsM protein, E coli
  • kpsT protein, E coli