title: An immunodominant epitope on 40 kilodalton outer membrane protein is conserved among different strains of Haemophilus (Histophilus) somnus.
abstract: Four murine monoclonal antibodies (mAb) were constructed against Haemophilus (Histophilus) somnus, an important bovine pathogen, and used to analyze immunologically significant antigenic determinants on these organisms. These mAbs specifically recognized immunodominant epitopes present on the 40 kilodalton (kD) fraction of the major outer membrane protein (OMP) of H. somnus. The 9D3 IgG1 kappa mAb recognized an immunodominant epitope on the 40 kD major outer membrane protein that is conserved or shared among all the three strains (septicemic, respiratory and uro-genital) of H. somnus. Two IgM kappa mAbs (4D6 and 10C2) recognized epitope(s) on the 40 kD OMP from septicemic and respiratory strains of H. somnus but none from the whole bacterial cell preparations. Another IgM kappa mAb 9D2 recognized an antigenic determinant on the 40 kD protein from the OMP as well as a whole bacterial cell preparation of a septicemic strain of H. somnus. These data demonstrate that, at least, three immunologically significant antigenic determinants on H. somnus are defined by mAbs against this bovine pathogen. Importantly, these studies suggest that the epitope present on the 40 kD major OMP, recognized by the 9D3 mAb, is immunodominant and conserved among septicemic, respiratory and urogenital strains, and is, therefore, suitable for further investigating its use in the development of an immunodiagnostic assay and also as a recombinant vaccine.
authors.affiliation: Department of Pathology, University of Guelph, Ontario.
authors.forename: S V
authors.initials: SV
authors.lastname: Silva
authors.forename: P B
authors.initials: PB
authors.lastname: Little
authors.forename: A
authors.initials: A
authors.lastname: Kaushik
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D018985:Epitopes, B-Lymphocyte / Q000276:immunology*; D006190:Haemophilus / Q000276:immunology*; D016056:Immunodominant Epitopes / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D018985:Epitopes, B-Lymphocyte; D016056:Immunodominant Epitopes