Neisseria meningitidis serogroup B Porin A (PorA)

Porin A (PorA) is a major class 1 outer membrane protein found in Neisseria meningitidis, particularly within serogroup B. It functions as a cation-selective porin that forms channels in the bacterial outer membrane, allowing the passive diffusion of small hydrophilic molecules (UniProt: P0A316). In the field of vaccinology, PorA is a highly immunodominant antigen and a primary component of outer membrane vesicle (OMV) vaccines. These vaccines, such as the OMV component of Bexsero, are designed to elicit protective bactericidal antibodies against the bacterium (Pollard et al., 2009). A significant challenge in targeting PorA is its high degree of sequence variability in the extracellular loops (VR1 and VR2), which defines the serosubtype and often limits the breadth of protection to specific bacterial strains (Sacchi et al., 1998). Consequently, modern meningococcal B vaccines often combine OMV-derived PorA with other conserved recombinant proteins to ensure broader coverage across diverse clinical isolates.

Other names

Class 1 outer membrane proteinPorin AMenB OMV PorAnMB_0543Major outer membrane protein P1

Induction of serum bactericidal antibodies (SBA) that recognize specific epitopes on the PorA protein, facilitating complement-mediated lysis and opsonophagocytosis of Neisseria meningitidis (EMA: Bexsero Summary of Product Characteristics).