Factor H binding protein subfamily A (fHbp subfamily A)

Factor H binding protein (fHbp) is a surface-exposed lipoprotein essential for the survival of Neisseria meningitidis within the human host (UniProt Q9K0U4). It is a key virulence factor that specifically binds human factor H, a down-regulator of the alternative complement pathway, allowing the bacteria to evade complement-mediated killing (PubMed: 19234461). The fHbp proteins are classified into two immunologically distinct subfamilies, A and B; subfamily A includes variants 2 and 3, which are genetically diverse from subfamily B (variant 1) (PubMed: 20685931). This target is a primary component of the Trumenba vaccine, which contains one lipidated fHbp variant from each subfamily to ensure broad coverage against various meningococcal serogroup B strains (FDA: Trumenba Label). Upon administration, the vaccine elicits antibodies that are bactericidal and can also inhibit the binding of factor H to the bacterial surface. This dual action enhances the host's ability to eliminate the pathogen through the complement system. Monitoring efficacy typically involves measuring serum bactericidal activity (hSBA) using human complement.

Other names

fHbpGNA1870LP2086Variant 2Variant 3Meningococcal surface protein

Induction of complement-mediated bactericidal antibodies that recognize the fHbp antigen and inhibit its ability to bind human factor H, thereby facilitating bacterial lysis.