Neisseria meningitidis group B PorA protein (PorA)

The **Neisseria meningitidis group B PorA protein** (PorA) is a major outer membrane porin found in all strains of *N. meningitidis*, including those causing meningococcal group B infections. PorA forms a trimeric β-barrel structure that creates cation-selective pores in the bacterial outer membrane, facilitating the passive diffusion of small hydrophilic molecules. PorA is highly immunogenic, particularly in its surface-exposed loops 1 and 4 (variable regions 1 and 2), which elicit bactericidal antibodies and make it a prominent candidate for vaccine development. However, PorA displays considerable sequence variability and phase variation, which can mediate immune escape and limit vaccine coverage. PorA does not have any direct approved drug ligands but is a key component of some group B meningococcal vaccines, where it functions as an antigen to stimulate protective immune responses. PorA also interacts with host complement inhibitors (such as C4bp), contributing further to immune evasion by the pathogen. No known human homologs or direct toxicity risks have been associated with targeting PorA by vaccines or therapeutic antibodies.

Other names

Class 1 outer membrane proteinPorin APorA protein

Induction of protective, bactericidal immune responses via antibody binding to PorA surface epitopes - Immune evasion via phase variation in PorA expression and loop sequence variability