title: A phase-variable capsule is involved in virulence of Campylobacter jejuni 81-176.
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.
authors.affiliation: Enteric Diseases Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Bacon
authors.forename: C M
authors.initials: CM
authors.lastname: Szymanski
authors.forename: D H
authors.initials: DH
authors.lastname: Burr
authors.forename: R P
authors.initials: RP
authors.lastname: Silver
authors.forename: R A
authors.initials: RA
authors.lastname: Alm
authors.forename: P
authors.initials: P
authors.lastname: Guerry
mesh_terms: D018528:ATP-Binding Cassette Transporters; D016667:Bacterial Capsules / Q000378:metabolism / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D016123:Campylobacter jejuni / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D005816:Genetic Complementation Test; D050356:Lipid Metabolism; D026901:Membrane Transport Proteins; D016296:Mutagenesis; D011134:Polysaccharides / Q000378:metabolism; D017422:Sequence Analysis, DNA; D014774:Virulence
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D011134:Polysaccharides; C068104:kpsM protein, E coli; C068103:kpsT protein, E coli