David Joel, Barkema Herman W, Guan Le Luo, De Buck Jeroen
Department of Production Animal Health, University of Calgary, 3330 Hospital Drive, T2N 4N1, Calgary, AB, Canada.
Department of Agriculture, Food & Nutritional Science, University of Alberta, Agriculture/Forestry Centre, Edmonton, AB, Canada.
Vet Res. 2014 Oct 2;45(1):96. doi: 10.1186/s13567-014-0096-5.
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.
早期检测由副结核分枝杆菌（MAP）引起的副结核病（JD）对于减少传播至关重要；因此，正在探索检测MAP或早期MAP感染标志物的新诊断技术和方法。目的是确定口服接种后6个月和9个月时与MAP感染相关的生物标志物。因此，使用从感染MAP的犊牛获得的全血细胞进行基因表达分析。所有接种MAP的犊牛对副结核菌素PPD特异性抗原有细胞介导的免疫反应（IFN-γ），60%的犊牛对MAP抗原有抗体反应。接种后6个月的基因表达分析显示趋化因子下调，即中性粒细胞β-防御素9样肽（BNBD9-Like）、S100钙结合蛋白A9（s100A9）和G蛋白偶联受体77（GPR77）或C5a过敏毒素趋化受体（C5a2）。此外，接种后9个月BOLA/MHC-1细胞内抗原呈递基因下调。同时，评估一些差异表达基因稳健性的qPCR实验显示，接种后3、6、9、12和15个月BOLA/MHC-I、BNBD9-Like持续下调，CD46上调。总之，测量这些基因的表达有可能用于MAP感染早期检测的诊断工具。
