title: Characterization of an immunoreactive 17.5-kilodalton outer membrane protein of Haemophilus somnus by using a monoclonal antibody.
abstract: A single outer membrane protein (OMP) of Haemophilus somnus, with an apparent molecular mass of 17.5 kDa, was identified in the sodium dodecyl sulfate (SDS)-insoluble fraction after extraction with 1% SDS-0.5 M NaCl-0.1% beta-mercaptoethanol. A hybridoma derived from mice immunized with H. somnus OMP fractions produced a monoclonal antibody (MAb), designated 20-3-5, that bound to the 17.5-kDa OMP of H. somnus. The MAb 20-3-5 epitope was present on 45 of 45 strains of H. somnus tested. MAb 20-3-5 cross-reacted with Haemophilus agni, Histophilus ovis, and Haemophilus haemoglobinophilus but not with 13 other species and subspecies of gram-negative bacteria. Immunoelectron-microscopic and antibody absorption studies revealed that the MAb 20-3-5 epitope is exposed on the surface of bacteria. In an immunoblot analysis, convalescent-phase sera obtained from calves with experimental H. somnus pneumonia contained antibodies to the 17.5-kDa OMP of H. somnus. Future studies will be directed toward examining the role of the 17.5-kDa OMP in immunity to H. somnus infections.
authors.affiliation: National Institute of Animal Health, Ibaraki, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Tagawa
authors.forename: M
authors.initials: M
authors.lastname: Haritani
authors.forename: N
authors.initials: N
authors.lastname: Yuasa
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D015153:Blotting, Western; D002417:Cattle; D000939:Epitopes; D006190:Haemophilus / Q000276:immunology*; D008970:Molecular Weight; D011014:Pneumonia / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D000954:Antigens, Surface; D001425:Bacterial Outer Membrane Proteins; D000939:Epitopes