title: Involvement of lipooligosaccharides of Haemophilus influenzae and Neisseria meningitidis in defensin-enhanced bacterial adherence to epithelial cells.
abstract: Stimulated neutrophils release a variety of antimicrobial peptides, including neutrophil defensins (HNP1-4). We have previously reported that neutrophil defensins enhanced the adherence of Haemophilus influenzae and Neisseria meningitidis to cultured respiratory epithelial cells. In this study, the effect of defensins on the adherence of H. influenzae and N. meningitidis lipooligosaccharide (LOS) mutants to epithelial cells was tested. Neutrophil defensins enhanced the adherence of the oligosaccharide mutants of H. influenzae and N. meningitidis, whilst the adherence of the lipid A mutants B29 of H. influenzae and lpxL1 and lpxL2 of N. meningitidis was not or only moderately stimulated by neutrophil defensins. The adherence of the N. meningitidis LOS negative mutant lpxA was not enhanced by defensins. These findings suggested that the secondary fatty acids of lipid A were involved in the defensin-enhanced adherence. LOS from strain H44/76 or HNP-LOS complexes did not affect or stimulate the adherence of N. meningitidis, although the defensin-enhanced adherence is specific for certain bacterial species having LOS in their outer membrane. These results indicated that LOS is involved in the defensin-enhanced adherence. However, the mechanism by which defensins and LOS interact with epithelial cells to promote bacterial adherence remains to be resolved.
authors.affiliation: Department of Medical Microbiology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Annelies D
authors.initials: AD
authors.lastname: Gorter
authors.forename: Jaap
authors.initials: J
authors.lastname: Oostrik
authors.forename: Peter
authors.initials: P
authors.lastname: van der Ley
authors.forename: Pieter S
authors.initials: PS
authors.lastname: Hiemstra
authors.forename: Jacob
authors.initials: J
authors.lastname: Dankert
authors.forename: Loek
authors.initials: L
authors.lastname: van Alphen
mesh_terms: D001422:Bacterial Adhesion / Q000187:drug effects*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002240:Carbohydrate Sequence; D002460:Cell Line; D023082:Defensins / Q000378:metabolism / Q000494:pharmacology*; D004847:Epithelial Cells / Q000382:microbiology*; D006193:Haemophilus influenzae / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D007830:Larynx / Q000382:microbiology; D008070:Lipopolysaccharides / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D009345:Neisseria meningitidis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D023082:Defensins; D008070:Lipopolysaccharides; C023023:lipid-linked oligosaccharides