title: Antigenic and/or phase variation of PorA protein in non-subtypable Neisseria meningitidis strains isolated in Spain.
abstract: The PorA protein is a potential candidate as a vaccine component against meningococcal disease. However, this protein experiences antigenic variation and is subject to phase variations to evade immune selective pressure. In this study, the mechanisms responsible for altered expression of the PorA protein were analysed in 50 non-subtypable strains isolated from patients with meningococcal disease in Spain. The porA gene was amplified from 47 of the 50 strains. The majority of isolates were not recognized by the subtyping panel, as a result of non-synonymous base changes in the variable regions of the porA gene. Two of these strains revealed a premature stop codon before the variable region VR1 of PorA due to a single base-pair substitution at position 109 of the porA coding region. Another two presented a homopolymeric tract of eight adenine residues in the coding region, producing a DNA strand-slippage mechanism and PorA phase variation.
authors.affiliation: Reference Laboratory for Neisseria, National Center of Microbiology, Institute of Health Carlos III, Ctra. Majadahonda-Pozuelo Km2, 28220 Majadahonda, Madrid, Spain.
authors.forename: Belen
authors.initials: B
authors.lastname: Alcalá
authors.affiliation: Reference Laboratory for Neisseria, National Center of Microbiology, Institute of Health Carlos III, Ctra. Majadahonda-Pozuelo Km2, 28220 Majadahonda, Madrid, Spain.
authors.forename: Celia
authors.initials: C
authors.lastname: Salcedo
authors.affiliation: Reference Laboratory for Neisseria, National Center of Microbiology, Institute of Health Carlos III, Ctra. Majadahonda-Pozuelo Km2, 28220 Majadahonda, Madrid, Spain.
authors.forename: Luisa
authors.initials: L
authors.lastname: Arreaza
authors.affiliation: Reference Laboratory for Neisseria, National Center of Microbiology, Institute of Health Carlos III, Ctra. Majadahonda-Pozuelo Km2, 28220 Majadahonda, Madrid, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Abad
authors.affiliation: Reference Laboratory for Neisseria, National Center of Microbiology, Institute of Health Carlos III, Ctra. Majadahonda-Pozuelo Km2, 28220 Majadahonda, Madrid, Spain.
authors.forename: Rocio
authors.initials: R
authors.lastname: Enríquez
authors.affiliation: Reference Laboratory for Neisseria, National Center of Microbiology, Institute of Health Carlos III, Ctra. Majadahonda-Pozuelo Km2, 28220 Majadahonda, Madrid, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: De La Fuente
authors.affiliation: Reference Laboratory for Neisseria, National Center of Microbiology, Institute of Health Carlos III, Ctra. Majadahonda-Pozuelo Km2, 28220 Majadahonda, Madrid, Spain.
authors.forename: Maria Jose
authors.initials: MJ
authors.lastname: Uría
authors.affiliation: Reference Laboratory for Neisseria, National Center of Microbiology, Institute of Health Carlos III, Ctra. Majadahonda-Pozuelo Km2, 28220 Majadahonda, Madrid, Spain.
authors.forename: Julio A
authors.initials: JA
authors.lastname: Vázquez
mesh_terms: D000940:Antigenic Variation; D014644:Genetic Variation; D006801:Humans; D008585:Meningitis, Meningococcal / Q000382:microbiology; D008969:Molecular Sequence Data; D009345:Neisseria meningitidis / Q000145:classification / Q000235:genetics* / Q000276:immunology; D018272:Porins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012703:Serotyping; D013030:Spain
chemical_list: D018272:Porins; C057699:porin protein, Neisseria