title: A mutation affecting expression of a major outer membrane protein of Moraxella catarrhalis alters serum resistance and survival in vivo.
abstract: A major outer membrane protein (CopB) of Moraxella catarrhalis is a target for antibodies that enhance clearance of this organism from the lungs of mice. A mini-Tn10kan transposon was inserted into the cloned copB gene from M. catarrhalis O35E, and an isogenic mutant unable to express the CopB protein was constructed by transforming this mutated gene into the wild-type strain. The mutant grew at the same rate as the wild-type parent strain in broth. Unlike the serum-resistant parent strain, this mutant was sensitive to killing by normal human serum, and its ability to survive and grow in the lungs of animals was impaired. Genetic restoration of CopB protein expression resulted in the simultaneous acquisition of wild-type levels of serum resistance and the ability to resist pulmonary clearance in vivo. Thus, the CopB protein of M. catarrhalis may be important in the interaction between this organism and the defense mechanisms of the respiratory tract.
authors.affiliation: Dept. of Microbiology, University of Texas Southwestern Medical Center, Dallas 75235-9048.
authors.forename: M E
authors.initials: ME
authors.lastname: Helminen
authors.forename: I
authors.initials: I
authors.lastname: Maciver
authors.forename: M
authors.initials: M
authors.lastname: Paris
authors.forename: J L
authors.initials: JL
authors.lastname: Latimer
authors.forename: S L
authors.initials: SL
authors.lastname: Lumbley
authors.forename: L D
authors.initials: LD
authors.lastname: Cope
authors.forename: G H
authors.initials: GH
authors.lastname: McCracken
authors.forename: E J
authors.initials: EJ
authors.lastname: Hansen
mesh_terms: D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000276:immunology; D001770:Blood Bactericidal Activity; D004195:Disease Models, Animal; D006801:Humans; D008171:Lung Diseases / Q000276:immunology*; D051379:Mice; D001936:Moraxella catarrhalis / Q000235:genetics* / Q000276:immunology / Q000472:pathogenicity; D016254:Mutagenesis, Insertional; D009154:Mutation; D016870:Neisseriaceae Infections / Q000276:immunology*; D015183:Restriction Mapping; D014774:Virulence
chemical_list: D001425:Bacterial Outer Membrane Proteins; C093197:CopB protein, Moraxella