title: Intestinal innate immunity to Campylobacter jejuni results in induction of bactericidal human beta-defensins 2 and 3.
abstract: Campylobacter jejuni is the most prevalent cause of bacterial diarrhea worldwide. Despite the serious health problems caused by this bacterium, human innate immune responses to C. jejuni infection remain poorly defined. Human beta-defensins, a family of epithelial antimicrobial peptides, are a major component of host innate defense at the gastrointestinal mucosal surface. In this study, the effect of two different C. jejuni wild-type strains on human intestinal epithelial innate responses was investigated. Up-regulation of beta-defensin gene and peptide expression during infection was observed and recombinant beta-defensins were shown to have a direct bactericidal effect against C. jejuni through disruption of cell wall integrity. Further studies using an isogenic capsule-deficient mutant showed that, surprisingly, the absence of the bacterial polysaccharide capsule did not change the innate immune responses induced by C. jejuni or the ability of C. jejuni to survive exposure to recombinant beta-defensins. This study suggests a major role for this family of antimicrobial peptides in the innate immune defense against this human pathogen.
authors.affiliation: Department of Infectious Diseases and Microbiology, Institute of Child Health, London WC1N 1EH, United Kingdom.
authors.forename: Matthias
authors.initials: M
authors.lastname: Zilbauer
authors.forename: Nick
authors.initials: N
authors.lastname: Dorrell
authors.forename: Parjeet K
authors.initials: PK
authors.lastname: Boughan
authors.forename: Andrew
authors.initials: A
authors.lastname: Harris
authors.forename: Brendan W
authors.initials: BW
authors.lastname: Wren
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Klein
authors.forename: Mona
authors.initials: M
authors.lastname: Bajaj-Elliott
mesh_terms: D016667:Bacterial Capsules / Q000737:chemistry / Q000502:physiology; D018938:Caco-2 Cells; D016123:Campylobacter jejuni / Q000276:immunology*; D002462:Cell Membrane / Q000502:physiology; D004847:Epithelial Cells / Q000276:immunology / Q000382:microbiology; D005786:Gene Expression Regulation; D019073:HT29 Cells; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology*; D007413:Intestinal Mucosa / Q000166:cytology / Q000276:immunology; D007422:Intestines / Q000166:cytology / Q000276:immunology* / Q000382:microbiology*; D011134:Polysaccharides / Q000737:chemistry / Q000502:physiology; D023083:beta-Defensins / Q000276:immunology*
chemical_list: C422950:DEFB103A protein, human; C106641:DEFB4A protein, human; D011134:Polysaccharides; D023083:beta-Defensins