Porin A (PorA) and associated outer membrane vesicle proteins of Neisseria meningitidis serogroup B (PorA/OMV)

Porin A (PorA) is a major class 1 outer membrane protein of Neisseria meningitidis serogroup B that functions as a cation-selective channel, facilitating the transport of small nutrients across the bacterial cell wall [1]. In vaccine pharmacology, PorA is typically delivered within Outer Membrane Vesicles (OMVs), which are spherical blebs released from the bacterial surface that contain a complex array of proteins and lipids [2]. These OMV-based antigens are critical for Neisseria meningitidis serogroup B prevention because the bacterium's polysaccharide capsule is poorly immunogenic and mimics human neural cell adhesion molecules, making protein-based targets essential for vaccine efficacy [3]. Vaccines targeting PorA and OMV proteins work by eliciting serum bactericidal antibodies that activate the host complement system to lyse the bacteria [4]. However, the high degree of sequence variability in the PorA surface loops necessitates the use of specific OMV strains or multi-component formulations to achieve broad protection against diverse meningococcal isolates [5]. The inclusion of OMVs in vaccines like Bexsero provides both a delivery system for PorA and an intrinsic adjuvant effect through residual bacterial components, though this can also contribute to increased reactogenicity in clinical settings [2, 5].

Other names

Porin AClass 1 outer membrane proteinOuter membrane vesiclesMenB OMVPorAMeningococcal outer membrane vesicle proteins

Induction of active immunity through the production of serum bactericidal antibodies that facilitate complement-mediated lysis of Neisseria meningitidis [4].