title: Expression of factor H binding protein in meningococcal strains can vary at least 15-fold and is genetically determined.
abstract: Factor H binding protein (fHbp) is a lipoprotein of Neisseria meningitidis important for the survival of the bacterium in human blood and a component of two recently licensed vaccines against serogroup B meningococcus (MenB). Based on 866 different amino acid sequences this protein is divided into three variants or two families. Quantification of the protein is done by immunoassays such as ELISA or FACS that are susceptible to the sequence variation and expression level of the protein. Here, selected reaction monitoring mass spectrometry was used for the absolute quantification of fHbp in a large panel of strains representative of the population diversity of MenB. The analysis revealed that the level of fHbp expression can vary at least 15-fold and that variant 1 strains express significantly more protein than variant 2 or variant 3 strains. The susceptibility to complement-mediated killing correlated with the amount of protein expressed by the different meningococcal strains and this could be predicted from the nucleotide sequence of the promoter region. Finally, the absolute quantification allowed the calculation of the number of fHbp molecules per cell and to propose a mechanistic model of the engagement of C1q, the recognition component of the complement cascade.
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Biagini
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Spinsanti
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: De Angelis
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Tomei
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Ferlenghi
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Scarselli
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Rigat
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Messuti
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Biolchi
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Muzzi
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Anderloni
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Brunella
authors.initials: B
authors.lastname: Brunelli
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Cartocci
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Buricchi
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Tani
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Stella
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Moschioni
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Del Tordello
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Colaprico
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Silvana
authors.initials: S
authors.lastname: Savino
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Marzia M
authors.initials: MM
authors.lastname: Giuliani
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Isabel
authors.initials: I
authors.lastname: Delany
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Mariagrazia
authors.initials: M
authors.lastname: Pizza
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Costantino
authors.affiliation: GSK Vaccines, 53100 Siena, Italy.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Norais
authors.affiliation: GSK Vaccines, 53100 Siena, Italy rino.r.rappuoli@gsk.com vega.x.masignani@gsk.com.
authors.forename: Rino
authors.initials: R
authors.lastname: Rappuoli
authors.affiliation: GSK Vaccines, 53100 Siena, Italy rino.r.rappuoli@gsk.com vega.x.masignani@gsk.com.
authors.forename: Vega
authors.initials: V
authors.lastname: Masignani
mesh_terms: D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D014644:Genetic Variation; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods; D008585:Meningitis, Meningococcal / Q000276:immunology / Q000382:microbiology; D022401:Meningococcal Vaccines / Q000276:immunology; D038541:Neisseria meningitidis, Serogroup B / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D013045:Species Specificity
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D022401:Meningococcal Vaccines; C484699:factor H-binding protein, Neisseria meningitidis
keywords: MenB vaccine; SRM-MS; antigen density; fHbp antigen; selected reaction monitoring mass spectrometry