A bacterial surface lipoprotein that binds host (human) complement factor H (fH, gene CFH), binding contributes to the avoidance of complement-mediated lysis by N.meningitidis. Binding of fH to the bacteria surface is independent of bacterial sialic acid moieties (PubMed:16751403). fH binding affinity is high enough that it may sequester plasma fH, depleting its circulating levels and de-regulating complement in the host (Probable). This protein induces high levels of bactericidal antibodies in mice (PubMed:12642606, PubMed:15039331, PubMed:15664958, PubMed:21753121, PubMed:23133374). Binds to host factor H (fH from human) (PubMed:16751403, PubMed:16785547, PubMed:19225461, PubMed:23133374). Both fHbp beta-barrels contact Sushi domains 6 and 7 in fH (also called complement control protein domains, CCP). This interaction probably mimics the normal (carbohydrate-dependent) mode of fH recruitement, regulating fH activity. Sucrose octasulphate inhibits the fHbp-fH interaction (PubMed:16785547, PubMed:19225461, PubMed:23133374). Surface exposed on encapsulated and non-encapsulated strains. In freshly innoculated cells no secreted protein is seen, as cultures grow the amount of protein in the cell supernatant increases. The amount of protein increases as cells approach stationary phase (at protein level). Divided into 3 domains by antibody recognition; domain A (27-119), domain B (120-183) and domain C (184-274). Domain A contains linear epitopes that are common to the three GNA 1870 (fHbp) variants, antibodies against it recognize N.meningitidis cells. Domain B contains linear epitopes common to variant 1 proteins but antibodies against it do not give a robust signal against N.meningitidis cells. Domain C does not have linear epitopes but antibodies against it recognize N.meningitidis cells. Bactericidal antibodies are directed against conformational epitopes located in the BC domain (PubMed:15664958). Structures show there are 2 beta barrel domains, 51-156 and 167-274 each form an 8-stranded antiparallel beta-barrel joined by linker between 157-166 (PubMed:16407174, PubMed:19225461, PubMed:21753121). Protein is lipidated in N.meningitidis upon growth in radioactive palmitic acid, probably on Cys-20. Bacteria are more sensitive to complement-mediated killing. Part of an outer membrane vesicle vaccine; antisera against this protein induce efficient complement-mediated killing of the homologous strain. Three antigenic variant groups were detected upon sequencing of group B strains; antibodies against a single variant group provide reduced protection against the other 2 groups. Thus inclusion of an example of each in a vaccine may provide adequate protection against all strains. Recombinant protein lipidation increases its immunogenicity (PubMed:12642606, PubMed:15039331). This is the variant used in the 5CVMB vaccine (PubMed:16825336). Engineering fHbp to include the antigenic epitopes of the 3 main group variants to produce a single protein for vaccine production has lead to a molecule with increased antigenic efficacy. This G1 variant has 23 changes compared to the MC58 standard; its X-ray structure is reported (PubMed:21753121). One of the major antigens of group B N.meningitidis and a powerful protective antigen. It is highly variable, over 300 protein variants have been seen (see Factor H binding protein sequence typing website). The protein in strain MC58 is called V1. Belongs to the factor H binding-protein family. Extended N-terminus.