Porin A (PorA) of Neisseria meningitidis (PorA)

Porin A (PorA) is a major class 1 outer membrane protein of Neisseria meningitidis, functioning as a cation-selective porin that facilitates the diffusion of small hydrophilic molecules across the bacterial outer membrane (UniProt P0A3S1; Massari et al., 2003, PubMed: 12644316). It is a key surface-exposed antigen and a primary target for the human immune response during infection and vaccination (Pollard et al., 2009, PubMed: 19740354). PorA is characterized by a 16-stranded beta-barrel structure with eight extracellular loops, where loops 1 and 4 (Variable Regions 1 and 2) are highly variable and contain the principal epitopes for neutralizing antibodies (Sacchi et al., 1998, PubMed: 9733631). Due to its high immunogenicity, PorA has been a central component in the development of outer membrane vesicle (OMV) vaccines, such as MeNZB and VA-MENGOC-BC, designed to control specific regional outbreaks of serogroup B meningococcal disease (O'Hallahan et al., 2004, PubMed: 15501601). However, the significant sequence diversity of PorA across different strains poses a major challenge for the development of a universal vaccine, as protection is typically strain-specific and requires matching the vaccine PorA subtype to the circulating strain (Tan et al., 2010, PubMed: 20637055).

Other names

Class 1 outer membrane proteinPorA proteinMajor outer membrane porin PorAMeningococcal PorA

Induction of host bactericidal antibodies that specifically target the surface-exposed variable loops (VR1 and VR2) of the PorA protein, facilitating complement-mediated lysis and opsonophagocytosis of Neisseria meningitidis (Pollard et al., 2009, PubMed: 19740354).