title: Immune response to an 18-kilodalton outer membrane antigen identifies lipoprotein 20 as a Helicobacter pylori vaccine candidate.
abstract: Experiments were performed using the standardized murine model of Helicobacter pylori infection to determine the immunogenicity of H. pylori outer membrane vesicles in immune protection. These vesicles, which are naturally shed from the surface of the bacterium, induce a protective response when administered intragastrically to mice in the presence of cholera holotoxin, despite the absence of the urease enzyme and associated Hsp54 chaperonin. Immunoblotting identified a specific serum immunoglobulin G (IgG) response to an 18-kDa outer membrane protein in a significant number of immunized animals. This commonly expressed, immunodominant protein was subsequently identified as lipoprotein 20 (Lpp20). Hybridoma backpacks secreting an IgG1 subclass monoclonal antibody to Lpp20 were generated in H. pylori-infected mice and were found to significantly reduce bacterial numbers, providing evidence that this surface-exposed antigen is a true vaccine candidate and not merely an antigenic marker for successful, protective immunization.
authors.affiliation: Departments of Surgery, Christchurch School of Medicine, Christchurch, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand. jacqui.keenan@chmeds.ac.nz
authors.forename: J
authors.initials: J
authors.lastname: Keenan
authors.forename: J
authors.initials: J
authors.lastname: Oliaro
authors.forename: N
authors.initials: N
authors.lastname: Domigan
authors.forename: H
authors.initials: H
authors.lastname: Potter
authors.forename: G
authors.initials: G
authors.lastname: Aitken
authors.forename: R
authors.initials: R
authors.lastname: Allardyce
authors.forename: J
authors.initials: J
authors.lastname: Roake
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000627:therapeutic use; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D000942:Antigens, Bacterial / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D001428:Bacterial Vaccines / Q000276:immunology* / Q000627:therapeutic use; D005260:Female; D016481:Helicobacter Infections / Q000276:immunology* / Q000517:prevention & control; D016480:Helicobacter pylori / Q000276:immunology*; D007116:Immunization, Passive; D016056:Immunodominant Epitopes; D008074:Lipoproteins / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D014611:Vaccination
chemical_list: D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001428:Bacterial Vaccines; D016056:Immunodominant Epitopes; D008074:Lipoproteins; C089630:Lpp20 protein, Helicobacter pylori