title: Gene-expression profiling of calves 6 and 9 months after inoculation with Mycobacterium avium subspecies paratuberculosis.
abstract: Early detection of Johne's disease (JD) caused by Mycobacterium avium subspecies paratuberculosis (MAP) is essential to reduce transmission; consequently, new diagnostic techniques and approaches to detect MAP or markers of early MAP infection are being explored. The objective was to identify biomarkers associated with MAP infection at 6 and 9 months after oral inoculation. Therefore, gene expression analysis was done using whole blood cells obtained from MAP-infected calves. All MAP-inoculated calves had a cell-mediated immune response (IFN-γ) to Johnin PPD specific antigens, and 60% had an antibody response to MAP antigens. Gene expression analysis at 6 months after inoculation revealed downregulation of chemoattractants, namely neutrophil beta-defensin-9 like peptide (BNBD9-Like), S100 calcium binding protein A9 (s100A9) and G protein coupled receptor 77 (GPR77) or C5a anaphylatoxin chemotactic receptor (C5a2). Furthermore, BOLA/MHC-1 intracellular antigen presentation gene was downregulated 9 months after inoculation. In parallel, qPCR experiments to evaluate the robustness of some differentially expressed genes revealed consistent downregulation of BOLA/MHC-I, BNBD9-Like and upregulation of CD46 at 3, 6, 9, 12, and 15 months after inoculation. In conclusion, measuring the expression of these genes has potential for implementation in a diagnostic tool for the early detection of MAP infection.
authors.affiliation: Department of Production Animal Health, University of Calgary, 3330 Hospital Drive, T2N 4N1, Calgary, AB, Canada. davij@ucalgary.ca.
authors.forename: Joel
authors.initials: J
authors.lastname: David
authors.affiliation: Department of Production Animal Health, University of Calgary, 3330 Hospital Drive, T2N 4N1, Calgary, AB, Canada. barkema@ucalgary.ca.
authors.forename: Herman W
authors.initials: HW
authors.lastname: Barkema
authors.affiliation: Department of Agriculture, Food & Nutritional Science, University of Alberta, Agriculture/Forestry Centre, Edmonton, AB, Canada. Leluo.Guan@ales.ualberta.ca.
authors.forename: Le Luo
authors.initials: le L
authors.lastname: Guan
authors.affiliation: Department of Production Animal Health, University of Calgary, 3330 Hospital Drive, T2N 4N1, Calgary, AB, Canada. jdebuck@ucalgary.ca.
authors.forename: Jeroen
authors.initials: J
authors.lastname: De Buck
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology* / Q000382:microbiology; D020869:Gene Expression Profiling / Q000662:veterinary; D007111:Immunity, Cellular; D016927:Mycobacterium avium subsp. paratuberculosis / Q000502:physiology*; D010283:Paratuberculosis / Q000276:immunology* / Q000382:microbiology; D013997:Time Factors; D059467:Transcriptome
chemical_list: D015415:Biomarkers