Antigenic and/or phase variation of PorA protein in non-subtypable Neisseria meningitidis strains isolated in Spain.
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.
Alcalá
Belen
B
Reference Laboratory for Neisseria, National Center of Microbiology, Institute of Health Carlos III, Ctra. Majadahonda-Pozuelo Km2, 28220 Majadahonda, Madrid, Spain.
Salcedo
Celia
C
Reference Laboratory for Neisseria, National Center of Microbiology, Institute of Health Carlos III, Ctra. Majadahonda-Pozuelo Km2, 28220 Majadahonda, Madrid, Spain.
Arreaza
Luisa
L
Reference Laboratory for Neisseria, National Center of Microbiology, Institute of Health Carlos III, Ctra. Majadahonda-Pozuelo Km2, 28220 Majadahonda, Madrid, Spain.
Abad
Raquel
R
Reference Laboratory for Neisseria, National Center of Microbiology, Institute of Health Carlos III, Ctra. Majadahonda-Pozuelo Km2, 28220 Majadahonda, Madrid, Spain.
Enríquez
Rocio
R
Reference Laboratory for Neisseria, National Center of Microbiology, Institute of Health Carlos III, Ctra. Majadahonda-Pozuelo Km2, 28220 Majadahonda, Madrid, Spain.
De La Fuente
Laura
L
Reference Laboratory for Neisseria, National Center of Microbiology, Institute of Health Carlos III, Ctra. Majadahonda-Pozuelo Km2, 28220 Majadahonda, Madrid, Spain.
Uría
Maria Jose
MJ
Reference Laboratory for Neisseria, National Center of Microbiology, Institute of Health Carlos III, Ctra. Majadahonda-Pozuelo Km2, 28220 Majadahonda, Madrid, Spain.
Vázquez
Julio A
JA
Reference Laboratory for Neisseria, National Center of Microbiology, Institute of Health Carlos III, Ctra. Majadahonda-Pozuelo Km2, 28220 Majadahonda, Madrid, Spain.
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
D018272:Porins; C057699:porin protein, Neisseria