title: Proteomics-based identification of immunodominant proteins of Brucellae using sera from infected hosts points towards enhanced pathogen survival during the infection.
abstract: Brucella (B.) species lack classical virulence factors, but escape effectively the immune response of the host. The species Brucella abortus and Brucella melitensis infect predominantly cattle and small ruminants such as sheep or goats, respectively, but account also for most human cases. These two species share remarkably similar genomes but different proteomes have been demonstrated. This might be one of the reasons for their host specificity. A comprehensive identification of immunodominant proteins of these two species using antibodies present in the serum of naturally infected ruminants might provide insight on the mechanism of their infection in different hosts. In the present study, whole-cell protein extracts of B. abortus and B. melitensis were separated using SDS-PAGE and western blotting was performed using field sera from cows, buffaloes, sheep and goats. Protein bands that matched with western blot signals were excised, digested with trypsin and subjected to protein identification using MALDI-TOF MS. Identified proteins included heat shock proteins, enzymes, binding proteins and hypothetical proteins. Antibodies against the same set of antigen were found for all species investigated, except for superoxide dismutase of B. melitensis for which antibodies were demonstrated only in sheep serum. Brucellae appear to express these proteins mainly for their survival in the host system during infection.
authors.affiliation: Institute of Animal Hygiene and Environmental Health, Centre for Infectious Medicine, Freie Universität Berlin, Germany; Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Bacterial Infections and Zoonoses, Jena, Germany.
authors.forename: Gamal
authors.initials: G
authors.lastname: Wareth
authors.affiliation: Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Bacterial Infections and Zoonoses, Jena, Germany.
authors.forename: Falk
authors.initials: F
authors.lastname: Melzer
authors.affiliation: Institute for Chemistry and Biochemistry, Freie Universität Berlin, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Weise
authors.affiliation: Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Bacterial Infections and Zoonoses, Jena, Germany.
authors.forename: Heinrich
authors.initials: H
authors.lastname: Neubauer
authors.affiliation: Institute of Animal Hygiene and Environmental Health, Centre for Infectious Medicine, Freie Universität Berlin, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Roesler
authors.affiliation: Institute of Animal Hygiene and Environmental Health, Centre for Infectious Medicine, Freie Universität Berlin, Germany. Electronic address: jayaseelan.murugaiyan@fu-berlin.de.
authors.forename: Jayaseelan
authors.initials: J
authors.lastname: Murugaiyan
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D001426:Bacterial Proteins / Q000276:immunology*; D015153:Blotting, Western; D002003:Brucella abortus / Q000276:immunology*; D017347:Brucella melitensis / Q000276:immunology*; D002020:Buffaloes; D002417:Cattle; D006041:Goats; D006360:Heat-Shock Proteins / Q000276:immunology; D013058:Mass Spectrometry; D018832:Molecular Chaperones / Q000276:immunology; D040901:Proteomics; D012756:Sheep; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013482:Superoxide Dismutase / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D013482:Superoxide Dismutase
keywords: Brucella; Host specificity; MALDI-TOF MS; Proteomics; Western blotting