RT Journal Article SR Electronic(1) A1 Alcalá, Belen A1 Salcedo, Celia A1 Arreaza, Luisa A1 Abad, Raquel A1 Enríquez, Rocio A1 De La Fuente, Laura A1 Uría, Maria Jose A1 Vázquez, Julio A.YR 2004 T1 Antigenic and/or phase variation of PorA protein in non-subtypable Neisseria meningitidis strains isolated in Spain JF Journal of Medical Microbiology, VO 53 IS 6 SP 515 OP 518 DO https://doi.org/10.1099/jmm.0.05517-0 PB Microbiology Society, SN 1473-5644, AB 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., UL https://www.microbiologyresearch.org/content/journal/jmm/10.1099/jmm.0.05517-0