Neisseria meningitidis serogroup B factor H binding protein (fHBP)

**Neisseria meningitidis serogroup B factor H binding protein (fHBP)** is a 27 kDa outer membrane surface-exposed lipoprotein unique to Neisseria meningitidis and a few related neisserial species[1][2][4][5]. fHBP binds human factor H, a key inhibitor of the complement alternative pathway, allowing the bacterium to evade innate immune defense mechanisms[1][3][4][5]. This immune evasion is essential for bacterial survival in human blood and contributes to meningococcal pathogenicity. fHBP is a critical virulence factor and the primary antigen in two licensed serogroup B meningococcal vaccines (Bexsero and Trumenba), inducing bactericidal antibodies that confer protection by promoting complement-mediated killing of the pathogen. fHBP displays substantial sequence diversity and variable expression among circulating strains, with levels of expression correlating to invasive disease potential and vaccine susceptibility[4][5]. Its structure consists of two domains (an N-terminal β-sheet and a C-terminal β-barrel), and its main epitope surface is accessible to functional antibodies[1][2]. **Relevant literature highlights:** - fHBP is the principal ligand for human factor H and acts as a molecular mimic to downregulate complement activation on the bacterial surface, thereby promoting immune evasion[1]. - Most clinical and carriage isolates of N. meningitidis express fHBP, but expression may be absent in some variants due to genetic variation[5]. - Sequence and promoter region diversity of fHBP are closely studied for predicting strain coverage and epidemiological monitoring[4][5]. This target is a validated and widely used component for vaccine development against invasive meningococcal disease caused by serogroup B.

Other names

Factor H-binding proteinfHbpNeisserial fHbpmeningococcal vaccine antigen fHbp

Vaccine-induced antibodies against fHBP bind to the bacterial surface, facilitating complement-mediated killing of Neisseria meningitidis[1][5].