Porin A outer-membrane protein (PorA)

Porin A (PorA) is a major outer membrane protein of Neisseria meningitidis, functioning as a cation-selective pore that facilitates the passive diffusion of small hydrophilic molecules across the bacterial outer membrane [1]. Structurally, it is a 16-stranded beta-barrel protein characterized by eight extracellular loops, with loops 1 and 4 being highly variable and serving as the primary targets for neutralizing antibodies [2]. In Neisseria meningitidis serogroup B, PorA is a significant therapeutic target because it induces a robust serum bactericidal antibody response, which is the established correlate of protection against invasive meningococcal disease [3]. Despite its immunogenicity, the high sequence diversity of the PorA loops poses a significant challenge for vaccine development, as immunity is often restricted to specific strains [4]. PorA is a central component of outer membrane vesicle (OMV) vaccines and is included in the multicomponent vaccine Bexsero to provide protection against specific serogroup B strains [5]. Its role in bacterial fitness and its accessibility on the cell surface make it a focal point for both diagnostic subtyping and preventative immunotherapy [1, 3]. Citations: [1] UniProt (P05022); [2] Massari et al. (2003), The Role of Porins in Neisseria meningitidis Pathogenicity; [3] Holst et al. (2009), Properties and clinical performance of vaccines containing outer membrane vesicles from Neisseria meningitidis; [4] Sacchi et al. (1998), Sequence diversity of PorA from Neisseria meningitidis; [5] Gossger et al. (2012), Immunogenicity and safety of a multicomponent meningococcal serogroup B vaccine.

Other names

PorAClass 1 outer membrane proteinPorin AMajor outer membrane protein P1

Induction of host serum bactericidal antibodies that facilitate complement-mediated killing of the pathogen [3].