Mycobacterium avium subsp. paratuberculosis antigens induce cellular immune responses in cattle. Mycobacterium avium subsp. paratuberculosis antigens induce cellular immune responses in cattle

Mycobacterium avium subspecies paratuberculosis (MAP) causes chronic progressive granulomatous enteritis leading to diarrhea, weight loss, and eventual death in ruminants. Commercially available vaccines provide only partial protection against MAP infection and can interfere with the use of current diagnostic tests for bovine tuberculosis in cattle. In the current study, we characterized immune responses in calves to vaccines containing either MAP fusion protein particles (MAP antigens Ag85A202-347-SOD1-72 -Ag85B173-330-74F1-148+669-786 as a fusion), recombinant MAP (rMAP) fusion protein or commercially available Silirum(R) vaccine. Overall design: Thirty-two Holstein-Friesian cattle, 2-3 months old were sourced from a commercial farm with no history of JD. Prior to the trial, the cattle (n = 32) tested negative for reactivity to protein purified derivative from Mycobacterum avium (PPDA) (Prionics, Schlieren-Zurich, Switzerland) in the whole-blood interferon-g (IFN-g) assay were selected from a larger group of animals (n = 45). Thirty-two calves were divided randomly into 4 vaccine groups of 8 animals. The cattle were grazed on pasture in a separate paddock during the trial. RNA was prepared from the antigen-stimulated leukocytes before vaccination (week 0) and after vaccination (weeks 6, 9 and 12 of the study) and analyzed using PlexSet-24 consisting of probes specific to 21 immune response genes and 3 reference genes

副结核分枝杆菌亚种（Mycobacterium avium subspecies paratuberculosis, MAP）可引发反刍动物的慢性进行性肉芽肿性肠炎，进而导致腹泻、体重减轻，最终死亡。当前市售疫苗仅能为MAP感染提供部分保护效力，且会干扰牛结核现有诊断检测在牛群中的应用。本研究中，我们对犊牛接种三类疫苗后的免疫应答进行了表征：分别为含MAP融合蛋白颗粒（融合形式为MAP抗原Ag85A202-347-SOD1-72-Ag85B173-330-74F1-148+669-786）的疫苗、重组MAP（rMAP）融合蛋白疫苗，以及市售Silirum®疫苗。
整体实验设计：选取32头2~3月龄的荷斯坦-弗里生牛（Holstein-Friesian cattle），来自无约翰氏病（JD）病史的商业牧场。试验前，我们从45头候选牛群中筛选出32头：经全血干扰素-γ（IFN-γ）检测，其对鸟分枝杆菌纯化蛋白衍生物（PPDA）的反应性呈阴性，PPDA由瑞士苏黎世施利伦的Prionics公司提供。将32头犊牛随机分为4组，每组8头。试验期间，所有牛只均在单独的牧场围栏内放牧饲养。分别于疫苗接种前（第0周）以及接种后（本研究第6、9、12周）采集抗原刺激的白细胞，从中提取RNA，采用包含21个免疫应答基因特异性探针与3个内参基因探针的PlexSet-24进行分析。