title: Immunoproteomic characterization of Brucella abortus 1119-3 preparations used for the serodiagnosis of Brucella infections.
abstract: The diagnosis of brucellosis is mainly based on the detection of anti-LPS antibodies. Due to substantial similarity of the O-polysaccharide of Brucella LPS to that of various other Gram-negative bacteria, serological tests of samples containing high amounts of LPS lack specificity. Hence, the development of assays based on more specific protein antigens is an essential subject in brucellosis research. The aim of this study was proteomic characterization of various antigen preparations of the diagnostic reference strain Brucella abortus 1119-3 and the identification of immunogenic proteins suitable for serological assays. Seventeen out of 383 protein spots of B. abortus 1119-3 were identified to be immunogenic by 2-D immunoblotting. These immunogenic spots were assigned to 6 proteins by MALDI-MS and nLC-ESI-MS/MS: Cu-Zn SOD, BCSP31, L7/L12, GroEL, GroES, and DnaK. All immunogenic proteins were present in three different antigen preparations investigated, i.e. native antigen, standard agglutination and commercially available agglutination antigen. 2-D immunoblotting of bacteria cross-reacting with Brucellae in agglutination tests proved that cross-reactivity of proteins is negligible. Surface enhanced laser desorption/ionization mass spectrometry (SELDI-MS) spectra also differentiated B. abortus clearly from cross-reacting bacteria. The combination of SELDI-MS analysis with the specificity of antibody binding will improve the identification of Brucella specific immunogenic proteins.
authors.affiliation: Department of Bacteriology, Bundeswehr Institute of Microbiology, Neuherbergstrasse 11, D-80937 Munich, Germany. SaschaAlDahouk@bundeswehr.org
authors.forename: Sascha
authors.initials: S
authors.lastname: Al Dahouk
authors.forename: Karsten
authors.initials: K
authors.lastname: Nöckler
authors.forename: Holger C
authors.initials: HC
authors.lastname: Scholz
authors.forename: Herbert
authors.initials: H
authors.lastname: Tomaso
authors.forename: Ralf
authors.initials: R
authors.lastname: Bogumil
authors.forename: Heinrich
authors.initials: H
authors.lastname: Neubauer
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000302:isolation & purification; D002003:Brucella abortus / Q000276:immunology*; D002006:Brucellosis / Q000175:diagnosis* / Q000276:immunology / Q000382:microbiology / Q000662:veterinary; D003429:Cross Reactions; D015180:Electrophoresis, Gel, Two-Dimensional; D006801:Humans; D040901:Proteomics / Q000379:methods*; D012698:Serologic Tests / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000942:Antigens, Bacterial