Albarrak S M, Waters W R, Stabel J R, Hostetter J M
Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, 1600 S 16th St, Ames, IA, 50011, USA.
USDA-ARS, National Animal Disease, 1920 Dayton Ave, Ames, IA, 50010, USA.
Vet Immunol Immunopathol. 2017 Aug;190:57-64. doi: 10.1016/j.vetimm.2017.07.007. Epub 2017 Jul 14.
A role for γδ T cells in protection against mycobacterial infections including Johne's disease (JD) has been suggested. In neonatal calves where the risk to infection with Mycobacterium avium subsp. paratuberculosis (MAP) is high, the majority of circulating CD3 lymphocytes are γδ TCR. Bovine γδ T cells are divided into two major subsets based on the surface expression of workshop cluster 1 (WC1). The WC1 subset, the predominant subset in periphery, is further divided into WC1.1 and WC1.2 subpopulations. The ability of γδ T cells to produce IFN-γ prior to CD4 αβ T cell activation could be crucial to the outcome of MAP infection. In the current study, cattle were naturally infected with MAP and were classified as either in the subclinical or clinical stage of infection. Compared to the control non-infected group, γδ T cell frequency in circulating lymphocytes was significantly lower in the clinical group. The observed decline in frequency was restricted to the WC1.2 subset, and was not associated with preferential migration to infection sites (distal-ileum). γδ T cells proliferated significantly in recall responses to stimulation with purified protein derivative from MAP (PPD-J) only in subclinically infected cattle. These responses were a heterogeneous mixture of WC1.1 and WC1.2 subsets. Proliferation and IFN-γ production by the WC1.1 γδ T cell subset was significantly higher in the subclinical group compared to the control and clinical groups. Our data indicates differences in MAP-specific ex-vivo responses of peripheral WC1 γδ T cells of cattle with the subclinical or clinical form of JD.
已有研究表明，γδ T细胞在抵御包括副结核病（JD）在内的分枝杆菌感染中发挥作用。在新生犊牛中，感染鸟分枝杆菌副结核亚种（MAP）的风险很高，循环中的大多数CD3淋巴细胞是γδ TCR。牛γδ T细胞根据车间簇1（WC1）的表面表达分为两个主要亚群。WC1亚群是外周的主要亚群，进一步分为WC1.1和WC1.2亚群。γδ T细胞在CD4 αβ T细胞激活之前产生IFN-γ的能力可能对MAP感染的结果至关重要。在本研究中，牛自然感染MAP，并被分类为处于感染的亚临床或临床阶段。与未感染的对照组相比，临床组循环淋巴细胞中的γδ T细胞频率显著降低。观察到的频率下降仅限于WC1.2亚群，且与优先迁移到感染部位（回肠远端）无关。仅在亚临床感染的牛中，γδ T细胞在对MAP纯化蛋白衍生物（PPD-J）刺激的回忆反应中显著增殖。这些反应是WC1.1和WC1.2亚群的异质混合物。与对照组和临床组相比，亚临床组中WC1.1 γδ T细胞亚群的增殖和IFN-γ产生显著更高。我们的数据表明，患有亚临床或临床形式JD的牛外周WC1 γδ T细胞的MAP特异性体外反应存在差异。
