Ludwig Latasha, Egan Rebecca, Baquero Monica, Mansz Amanda, Plattner Brandon L
Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
Vet Immunol Immunopathol. 2019 Oct;216:109919. doi: 10.1016/j.vetimm.2019.109919. Epub 2019 Aug 6.
Mucosal surfaces such as the gastrointestinal tract, and skin are the front line of host defence and immunity against many pathogens. Gamma delta (γδ) T lymphocytes preferentially localize to the mucosal surfaces in several species including cattle, and are thought to play crucial roles in immunosurveillance and host defence, particularly against mycobacteria. Many γδ T cells are present in young calves, which is the period when calves are thought to be initially exposed to Mycobacterium avium subspecies paratuberculosis (Map). The role of mucosal γδ T cells in cattle, especially during host-pathogen interactions during early pre-clinical phases of infectious disease remains unclear. The purposes of this study were to investigate and characterize WC1 and WC1 γδ T cell subsets in various segments of the gastrointestinal (GI) tract of young calves, and then to examine γδ T cell subsets in the distal small intestine of calves after experimental intestinal Map infection by direct Peyer's patch inoculation. We show that in healthy calves, the relative proportion of γδ T cells is constant throughout the GI mucosa, though the ileum has significantly more γδ T cells. In the distal intestine, γδ T cells are mainly WC1 and primarily located within the lamina propria of the jejunum and ileum. In Map-infected intestine, there are higher numbers of γδ T cells in the lamina propria and a greater proportion of WC1 cells within the epithelial layer compared to control calves. While WC1 γδ T cells preferentially localize to the distal small intestine of healthy calves, WC1 γδ T cells are increased in the intestinal mucosa during Map infection, which is suggestive of effector cell function. Further, spectral microscopy and flow cytometry in tandem will lead to improved understanding of the functions of these cells during health and disease.
胃肠道和皮肤等黏膜表面是宿主抵御多种病原体的第一道防线和免疫防线。γδ T淋巴细胞在包括牛在内的多个物种中优先定位于黏膜表面，被认为在免疫监视和宿主防御中发挥关键作用，尤其是针对分枝杆菌。许多γδ T细胞存在于幼牛中，这一时期被认为是小牛最初接触副结核分枝杆菌（Map）的时期。黏膜γδ T细胞在牛中的作用，尤其是在传染病临床前期早期宿主与病原体相互作用期间，仍不清楚。本研究的目的是调查和表征幼牛胃肠道（GI）各段中的WC1和WC1 γδ T细胞亚群，然后通过直接接种派尔集合淋巴结来检查实验性肠道Map感染后小牛远端小肠中的γδ T细胞亚群。我们发现，在健康小牛中，γδ T细胞的相对比例在整个胃肠道黏膜中是恒定的，尽管回肠中的γδ T细胞明显更多。在远端肠道中，γδ T细胞主要是WC1细胞，主要位于空肠和回肠的固有层内。与对照小牛相比，在感染Map的肠道中，固有层中的γδ T细胞数量更多，上皮层中的WC1细胞比例更大。虽然WC1 γδ T细胞优先定位于健康小牛的远端小肠，但在Map感染期间，肠道黏膜中的WC1 γδ T细胞会增加，这表明其具有效应细胞功能。此外，光谱显微镜和流式细胞术联用将有助于更好地了解这些细胞在健康和疾病状态下的功能。
