title: A monoclonal antibody directed against a serotype-specific, outer-membrane protein of Haemophilus influenzae type b.
abstract: Monoclonal antibodies (Mabs) were produced against outer-membrane proteins (OMPs) of Haemophilus influenzae type b. The clones were screened by ELISA with outer-membrane preparations of H. influenzae type b and untypable strains as coating antigens. Antibodies directed against the proteins of mol. wt (10(3)) 43, 37 and 13 were identified by immunoblotting of SDS-PAGE patterns of OMPs. Proteolytic enzyme treatments of the OMPs resulted in reduction of Mab reactivity as measured by ELISA. Furthermore, the absence of reactivity of Mab Hb-2 with a preparation of lipopolysaccharide confirmed the protein nature of its corresponding epitope. Binding assays with live bacteria showed that Hb-2 reacted with a cell surface-exposed antigenic determinant. Mab Hb-2 was bactericidal in vitro in the presence of complement. The characterisation of Hb-2 (IgG2a) by Western immunoblotting analysis revealed that it was directed against the 37 X 10(3)-mol. wt OMP. In a dot-enzyme immunoassay, Hb-2 reacted specifically with 326 strains of H. influenzae type b. It did not cross-react with the other serotypes or untypable strains of H. influenzae or with other bacterial species. This is the first report of a monoclonal antibody identifying a serotype-specific surface-exposed OMP of H. influenzae type b.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D000954:Antigens, Surface / Q000276:immunology; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D000939:Epitopes; D006193:Haemophilus influenzae / Q000276:immunology*; D008070:Lipopolysaccharides / Q000276:immunology; D010447:Peptide Hydrolases; D012703:Serotyping / Q000379:methods
chemical_list: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D001425:Bacterial Outer Membrane Proteins; D000939:Epitopes; D008070:Lipopolysaccharides; D010447:Peptide Hydrolases