Class 1 outer membrane protein PorA (P1.4) (PorA P1.4)

Outer membrane protein PorA (P1.4) is a major surface-exposed protein of Neisseria meningitidis, the bacterium responsible for invasive meningococcal disease, including meningitis and sepsis [1, 6]. It functions as a cation-selective porin, forming trimeric channels in the outer membrane that facilitate the transport of small molecules and nutrients [6]. The P1.4 designation refers to a specific serosubtype defined by the sequence of its variable regions (VR1 and VR2), which are the primary targets for host immune responses [8]. Due to its high immunogenicity, PorA P1.4 is a critical component of several meningococcal B vaccines, such as Bexsero and MeNZB, where it is typically presented within outer membrane vesicles (OMVs) [2, 4]. These vaccines work by inducing bactericidal antibodies that trigger complement-mediated killing of the bacteria [4, 7]. However, the effectiveness of PorA-targeted therapies is challenged by the protein's high degree of antigenic variation and phase variation, which allow the bacteria to escape immune detection [1, 8]. Consequently, PorA-based protection is often strain-specific, necessitating the inclusion of multiple antigens in modern vaccine formulations [4, 13].

Other names

Porin AP1.4PorA P1.7-2,4Class 1 OMPOuter membrane protein PorA

Induction of host bactericidal antibodies that recognize the PorA protein on the bacterial surface, triggering the classical complement pathway and resulting in complement-mediated lysis and opsonophagocytosis of Neisseria meningitidis [4, 7].