title: Identification of a gene (lpt-3) required for the addition of phosphoethanolamine to the lipopolysaccharide inner core of Neisseria meningitidis and its role in mediating susceptibility to bactericidal killing and opsonophagocytosis.
abstract: We have identified a gene, lpt-3, that is required for the addition of phosphoethanolamine to the 3-position (PEtn-3) on the beta-chain heptose (HepII) of the inner core lipopolysaccharide (LPS) of Neisseria meningitidis (Nm). The presence of this PEtn-3 substituent is characteristic of the LPS of a majority ( approximately 70%) of hypervirulent Nm strains, irrespective of capsular serogroup, and is required for the binding of a previously described monoclonal antibody (mAb B5) to a surface-accessible epitope. All strains of Nm that have PEtn-3 possess the lpt-3 gene. In some lpt-3-containing strains, the 3-position on HepII is preferentially substituted by glucose instead of PEtn, the result of lgtG phase variation mediated by slippage of a homopolymeric tract of cytidines. Inactivation of lpt-3 resulted in loss of PEtn-3, lack of reactivity with mAb B5 and conferred relative resistance to bactericidal killing and opsonophagocytosis by mAb B5 in vitro. Thus, the identification of lpt-3 has facilitated rigorous genetic, structural and immunobiological definition of an immunodominant epitope that is a candidate immunogen for inclusion in an LPS-based vaccine to protect against invasive meningococcal disease.
authors.affiliation: Molecular Infectious Diseases Group, University of Oxford Department of Paediatrics, John Radcliffe Hospital, Oxford OX3 9DS, UK.
authors.forename: Fiona G
authors.initials: FG
authors.lastname: Mackinnon
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Cox
authors.forename: Joyce S
authors.initials: JS
authors.lastname: Plested
authors.forename: Christoph M
authors.initials: CM
authors.lastname: Tang
authors.forename: Katherine
authors.initials: K
authors.lastname: Makepeace
authors.forename: Philip A
authors.initials: PA
authors.lastname: Coull
authors.forename: J Claire
authors.initials: JC
authors.lastname: Wright
authors.forename: Ronald
authors.initials: R
authors.lastname: Chalmers
authors.forename: Derek W
authors.initials: DW
authors.lastname: Hood
authors.forename: James C
authors.initials: JC
authors.lastname: Richards
authors.forename: E Richard
authors.initials: ER
authors.lastname: Moxon
mesh_terms: D000911:Antibodies, Monoclonal / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004983:Ethanolamines / Q000378:metabolism*; D005798:Genes, Bacterial / Q000502:physiology*; D008070:Lipopolysaccharides / Q000378:metabolism*; D016254:Mutagenesis, Insertional; D009345:Neisseria meningitidis / Q000235:genetics / Q000378:metabolism*; D010587:Phagocytosis; D010641:Phenotype; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins; D004983:Ethanolamines; D008070:Lipopolysaccharides; C005448:phosphorylethanolamine; D017853:Phosphotransferases (Alcohol Group Acceptor)