Neisseria meningitidis outer membrane vesicle PorA and associated surface proteins (PorA/OMV)

PorA is a major class 1 outer membrane protein of Neisseria meningitidis that functions as a cation-selective porin, facilitating the transport of small hydrophilic molecules across the bacterial outer membrane (UniProt: P0A725). It is a highly immunogenic protein and serves as a primary target for the host's bactericidal antibody response during infection (PubMed: 22939900). Because PorA is highly variable among different strains, it is often delivered via outer membrane vesicles (OMVs), which are naturally occurring blebs of the bacterial membrane that preserve the protein's native conformation and include other surface antigens like PorB, RmpM, Opa, and Opc (PubMed: 15507154). These OMV-based formulations are critical components of vaccines designed to protect against Serogroup B meningococcal disease, for which traditional polysaccharide vaccines are ineffective due to the similarity between the Serogroup B capsule and human neural tissues (CDC: Meningococcal Vaccination). In clinical applications, such as the Bexsero vaccine, the OMV component provides specific protection against strains expressing matching PorA serosubtypes while also providing a synergistic effect with other recombinant antigens (EMA: Bexsero Summary of Product Characteristics). The primary mechanism of action involves the induction of serum bactericidal antibodies that trigger the complement system to lyse the bacteria. Monitoring efficacy typically involves measuring bactericidal titers against specific reference strains using the human serum bactericidal assay (hSBA).

Other names

Porin AClass 1 outer membrane proteinOMV-associated antigensMeningococcal outer membrane vesiclePorA/OMV complex

Induction of complement-mediated bactericidal antibody response