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 WC1neg 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 WC1neg 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 WC1neg 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.

中文翻译：

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健康和鸟分枝杆菌感染结核的小牛肠道粘膜中的WC1 +和WC1negγδT淋巴细胞。

诸如胃肠道和皮肤的粘膜表面是宿主防御和抵抗许多病原体的免疫力的第一线。伽玛三角洲（γδ）T淋巴细胞优先定位于包括牛在内的多个物种的粘膜表面，并被认为在免疫监视和宿主防御（尤其是针对分枝杆菌的防御）中起着至关重要的作用。幼小犊牛中存在许多γδT细胞，这一时期被认为是小牛最初接触鸟分枝杆菌亚种副结核病（地图）。牛粘膜γδT细胞的作用，特别是在传染病临床前早期阶段的宿主-病原体相互作用期间，尚不清楚。这项研究的目的是调查和表征幼小肠胃肠道（GI）各个部分中的WC1 +和WC1negγδT细胞亚群，然后在实验性肠胃图检查后检查小腿远端小肠中的γδT细胞亚群。直接通过派伊尔氏菌斑接种来感染。我们表明，在健康的犊牛中，尽管回肠具有明显更多的γδT细胞，但在整个GI粘膜中γδT细胞的相对比例是恒定的。在远端肠中，γδT细胞主要为WC1neg，主要位于空肠和回肠的固有层内。与对照犊牛相比，在Map感染的肠道中，固有层中的γδT细胞数量更高，而上皮层中的WC1 +细胞比例更高。虽然WC1negγδT细胞优先定位于健康小牛的远端小肠，但在Map感染期间，肠道粘膜中WC1 +γδT细胞增加，这提示效应细胞功能。此外，光谱显微镜和流式细胞仪相结合将导致人们更好地了解这些细胞在健康和疾病期间的功能。