title: Immunization with recombinant class 1 outer-membrane protein from Neisseria meningitidis: influence of liposomes and adjuvants on antibody avidity, recognition of native protein and the induction of a bactericidal immune response against meningococci.
abstract: The porA gene from Neisseria meningitidis was cloned into the pRSETA vector and recombinant class 1 outer-membrane protein expressed at high levels in Escherichia coli. The protein was readily purified by affinity chromatography on a Ni2+ matrix and used for immunization of mice with conventional AI(OH)3 adjuvant, with experimental adjuvants which have the potential for human use, and with liposomes. The resulting sera were analysed for the magnitude, subclass distribution and antigenic specificity of the immune response. In addition, surface plasmon resonance (SPR) was used to quantify antibody avidity by analysis of the kinetics of binding to native class 1 protein. Immunization with conventional and experimental adjuvants induced antibodies of low avidity that did not recognize native class 1 protein. In contrast, immunization with recombinant protein in liposomes induced antibodies of high avidity which recognized native class 1 protein, as measured by their ability to label meningococcal cells in immunofluorescence assays and to inhibit the binding of a protective mAb. These properties were associated with the presence in sera of high levels of antibodies with the ability to induce complement-mediated killing of meningococci. These data show that liposomes containing recombinant class 1 protein represent a potential basis of future vaccines, of defined composition, designed for the prevention of group B meningococcal infections.
authors.affiliation: Molecular Microbiology Group, University of Southampton Medical School, Southampton General Hospital, Southampton SO16 6YD, UK.
authors.forename: Myron
authors.initials: M
authors.lastname: Christodoulides
authors.affiliation: Molecular Microbiology Group, University of Southampton Medical School, Southampton General Hospital, Southampton SO16 6YD, UK.
authors.forename: Joy L
authors.initials: JL
authors.lastname: Brooks
authors.affiliation: Molecular Microbiology Group, University of Southampton Medical School, Southampton General Hospital, Southampton SO16 6YD, UK.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Rattue
authors.affiliation: Molecular Microbiology Group, University of Southampton Medical School, Southampton General Hospital, Southampton SO16 6YD, UK.
authors.forename: John E
authors.initials: JE
authors.lastname: Heckels
mesh_terms: D000276:Adjuvants, Immunologic; D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis / Q000097:blood / Q000276:immunology*; D000915:Antibody Affinity; D001428:Bacterial Vaccines / Q000276:immunology*; D001770:Blood Bactericidal Activity; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D006801:Humans; D007114:Immunization; D008081:Liposomes; D051379:Mice; D008807:Mice, Inbred BALB C; D009345:Neisseria meningitidis / Q000235:genetics / Q000276:immunology*; D018272:Porins / Q000235:genetics / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology / Q000302:isolation & purification; D014614:Vaccines, Synthetic / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D008081:Liposomes; D018272:Porins; D011994:Recombinant Proteins; D014614:Vaccines, Synthetic; C057699:porin protein, Neisseria