title: Serum antibodies to outer membrane proteins (OMPs) of Moraxella (Branhamella) catarrhalis in patients with bronchiectasis: identification of OMP B1 as an important antigen.
abstract: Moraxella (Branhamella) catarrhalis is a common cause of lower respiratory tract infections in adults and of otitis media in children. Little is known about the human immune response to this bacterium. In this study, immunoblot assays were performed to detect serum immunoglobulin G antibodies directed at purified outer membrane of M. catarrhalis. Twelve serum samples, two each from six patients with bronchiectasis who were persistently colonized with this organism, were tested with their homologous M. catarrhalis sputum isolates. In all the sera, the most prominent and consistent antibody response was to a minor 84-kDa outer membrane protein, OMP B1. Immunoblot adsorption assays show that these antibodies recognize surface exposed epitopes on OMP B1. Further analysis of human serum antibodies eluted from the surface of intact bacterial cells shows that these surface-exposed epitopes on OMP B1 are heterogeneous among strains of M. catarrhalis. OMP B1 is therefore an important OMP antigen on the surface of M. catarrhalis for the human immune response to infection by this bacterium.
authors.affiliation: Division of Pulmonary Medicine, State University of New York at Buffalo.
authors.forename: S
authors.initials: S
authors.lastname: Sethi
authors.forename: S L
authors.initials: SL
authors.lastname: Hill
authors.forename: T F
authors.initials: TF
authors.lastname: Murphy
mesh_terms: D000328:Adult; D000368:Aged; D000907:Antibodies, Bacterial / Q000276:immunology*; D000918:Antibody Specificity; D000942:Antigens, Bacterial / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000276:immunology*; D001987:Bronchiectasis / Q000276:immunology*; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D001936:Moraxella catarrhalis / Q000276:immunology*; D012150:Polymorphism, Restriction Fragment Length; D013045:Species Specificity
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D004269:DNA, Bacterial; D007074:Immunoglobulin G