Ewer Katie, Cockle Paul, Gordon Steve, Mansoor Huma, Govaerts Marc, Walravens Karl, Marché Sylvie, Hewinson Glyn, Vordermeier Martin
TB Research Group, Veterinary Laboratories Agency-Weybridge, New Haw, Addlestone, Surrey KT15 3NB, United Kingdom.
Clin Vaccine Immunol. 2006 Jan;13(1):90-7. doi: 10.1128/CVI.13.1.90-97.2006.
The definition of antigens for the diagnosis of human and bovine tuberculosis is a research priority. If diagnosis is to be used alongside Mycobacterium bovis BCG-based vaccination regimens, it will be necessary to have reagents that allow the discrimination of infected and vaccinated animals. A list of 42 potential M. bovis-specific antigens was prepared by comparative analysis of the genomes of M. bovis, M. avium subsp. avium, M. avium subsp. paratuberculosis, and Streptomyces coelicolor. Potential antigens were tested by applying them in a high-throughput peptide-based screening system to M. bovis-infected and BCG-vaccinated cattle and to cattle without prior exposure to M. bovis. A response hierarchy of antigens was established by comparing responses in infected animals. Three antigens (Mb2555, Mb2890, and Mb3895) were selected for further study, as they were strongly recognized in experimentally infected animals but with low or no frequency in BCG-vaccinated and naïve cows. Interestingly, all three antigens were recognized in animals vaccinated against Johne's disease, suggesting the presences of epitopes cross-reacting with M. avium subsp. paratuberculosis antigens. Eight peptides from the three antigens studied in detail were identified as immunodominant and were characterized in terms of major histocompatibility complex class II restriction element usage and shown to be restricted through both DR and DQ molecules. Reasons for antigenic cross-reactivity with M. avium subsp. paratuberculosis and refinement of the in silico strategy to predict such cross-reactivity from the primary protein sequence will be discussed. Evaluation of the peptides identified from the three dominant antigens by use of larger field studies is now a priority.
用于诊断人和牛结核病的抗原定义是一项研究重点。如果要将诊断与基于牛分枝杆菌卡介苗的疫苗接种方案同时使用，就需要有能够区分感染动物和接种疫苗动物的试剂。通过对牛分枝杆菌、鸟分枝杆菌亚种鸟型、鸟分枝杆菌亚种副结核分枝杆菌和天蓝色链霉菌的基因组进行比较分析，列出了42种潜在的牛分枝杆菌特异性抗原。通过将这些潜在抗原应用于基于肽的高通量筛选系统，对感染牛分枝杆菌和接种卡介苗的牛以及未接触过牛分枝杆菌的牛进行检测。通过比较感染动物的反应，建立了抗原反应等级。选择了三种抗原（Mb2555、Mb2890和Mb3895）进行进一步研究，因为它们在实验感染的动物中得到强烈识别，但在接种卡介苗的牛和未接触过牛分枝杆菌的牛中识别频率较低或无识别。有趣的是，在接种了抗副结核的动物中识别出了所有这三种抗原，这表明存在与鸟分枝杆菌亚种副结核分枝杆菌抗原发生交叉反应的表位。确定了来自详细研究的三种抗原的八个肽段为免疫显性肽段，并对其主要组织相容性复合体II类限制元件的使用情况进行了表征，结果表明它们通过DR和DQ分子受到限制。将讨论与鸟分枝杆菌亚种副结核分枝杆菌发生抗原交叉反应的原因以及从一级蛋白质序列预测这种交叉反应的计算机策略的优化。现在优先事项是通过更大规模的现场研究评估从三种显性抗原中鉴定出的肽段。
