TB Research Group, Veterinary Laboratories Agency, Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, United Kingdom.
J Clin Microbiol. 2010 Sep;48(9):3176-81. doi: 10.1128/JCM.00420-10. Epub 2010 Jun 30.
The tuberculin skin test has been used for the diagnosis of bovine and human tuberculosis (TB) for over a hundred years. However, the specificity of the test is compromised by vaccination with the Mycobacterium bovis-derived vaccine strain bacille Calmette-Guérin (BCG). Since current promising vaccines against bovine TB are based on heterologous prime-boost combinations that include BCG, there is a need for diagnostic tests for differentiating infected from vaccinated animals (DIVA). The application of antigens such as ESAT-6 and CFP-10 for DIVA has so far been realized largely through their application in the blood-based gamma interferon release assay. In the current study, we have reassessed the potential of such antigens as skin test reagents for DIVA in cattle. A cocktail of the Mycobacterium tuberculosis complex recombinant protein antigens ESAT-6, CFP-10, MPB70, and MPB83 elicited delayed-type hypersensitivity (DTH) skin test responses in 78% of naturally infected tuberculin-positive cattle. Importantly, this cocktail induced no skin responses in BCG-vaccinated cattle despite them being sensitized for strong tuberculin responses. Further optimization of skin test antigen combinations identified that the inclusion of Rv3615c (Mb3645c) enhanced skin test sensitivity in naturally infected cattle without compromising specificity. In addition, we demonstrate for the first time the utility of synthetic peptides as promising skin test antigens for bovine TB for DIVA. Our data provide a promising basis for the future development of skin tests for DIVA with practical relevance for TB diagnosis in both veterinary and clinical settings.
结核菌素皮肤试验已被用于诊断牛和人类结核病（TB）一百多年。然而，由于使用牛分枝杆菌来源的疫苗株卡介苗（BCG）进行了疫苗接种，该测试的特异性受到了影响。由于目前针对牛结核病的有希望的疫苗是基于包括 BCG 在内的异源初免-加强组合，因此需要区分感染动物和接种疫苗动物的诊断测试（DIVA）。ESAT-6 和 CFP-10 等抗原在 DIVA 中的应用主要是通过在基于血液的γ干扰素释放测定中应用来实现的。在本研究中，我们重新评估了这些抗原作为 DIVA 皮肤测试试剂在牛中的潜力。结核分枝杆菌复合体重组蛋白抗原 ESAT-6、CFP-10、MPB70 和 MPB83 的混合物在 78%的自然感染结核菌素阳性牛中引起了迟发型超敏（DTH）皮肤测试反应。重要的是，尽管 BCG 接种的牛对结核菌素反应强烈，但该混合物未引起皮肤反应。进一步优化皮肤测试抗原组合发现，包含 Rv3615c（Mb3645c）可提高自然感染牛的皮肤测试敏感性，而不会影响特异性。此外，我们首次证明了合成肽作为用于 DIVA 的牛结核病有前途的皮肤测试抗原的实用性。我们的数据为未来开发用于 DIVA 的皮肤测试提供了有希望的基础，这对于兽医和临床环境中的 TB 诊断具有实际意义。
