The major functions of γδ T cells in mammals overlap with those of αβ T cells but differ in that γδ T cells are rapid responders and see different types of antigens. While γδ T cells have been shown to be a major population of circulating lymphocytes in artiodactyl species such as cattle, sheep, and pigs, less is known about these cells in goats, an important agricultural species. We have recently shown that WC1, a γδ T cell-specific family of hybrid pattern recognition receptors/co-receptors, is a multigenic family in goats expanded beyond what occurs in cattle. This study was conducted to address some of the limitations of previous studies in determining the proportions of γδ T cells, WC1⁺ γδ T cells as well as the WC1.1⁺ and WC1.2⁺ subpopulations in blood and to evaluate their responses to various pathogens. Previously, the proportion of caprine γδ T cells was determined using a monoclonal antibody (mAb) 86D that we show here does not react with all γδ T cells thereby underestimating their contribution to the lymphocyte population. Using a mAb reactive with the TCRδ constant region we found the proportion of γδ T cells in blood was not significantly less than that of either CD4 or CD8 T cells and did not decrease with age after 6 months. γδ T cells that expressed WC1 ranged from ~20 to 85% of the total γδ T cells. Less than half of those were classified as WC1.1⁺ or WC1.2⁺ by mAb staining thus indicating a third major WC1⁺ population. We found that naïve γδ T cells proliferated in cultures of PBMC stimulated with antigens of Leptospira or Mycobacterium avium paratuberculosis (MAP) more than they did in control medium cultures or in those stimulated with M. bovis BCG antigens and that the responding γδ T cells included both WC1⁺ and WC1^- cells. In ex vivo PMA/ionomycin-stimulated cultures of WC1^- γδ T cells but not WC1⁺ cells produced both IL-17 and IFNγ. In longterm cultures with Leptospira or MAP both WC1^- and WC1⁺ cells proliferated but only WC1^- γδ T cells produced IL-17. In conclusion, goats have a substantial number of WC1^- and WC1⁺ γδ T cells in PBMC that do not decrease with animal age after 6 months; both populations respond to bacterial antigens as naïve cells but in these cultures only the WC1^- γδ cells produc IL-17 and IFNγ .

哺乳动物中γδ T 细胞的主要功能与αβ T 细胞的主要功能重叠，但不同之处在于γδ T 细胞是快速反应者并且看到不同类型的抗原。虽然 γδ T 细胞已被证明是牛、绵羊和猪等偶蹄动物中循环淋巴细胞的主要群体，但对山羊这一重要的农业物种中的这些细胞知之甚少。我们最近表明，WC1 是一种 γδ T 细胞特异性混合模式识别受体/共受体家族，是山羊中的一个多基因家族，其范围超出了牛的范围。本研究旨在解决先前研究在确定 γδ T 细胞、WC1 ⁺ γδ T 细胞以及 WC1.1 ⁺和 WC1.2 ^{+的比例方面的一些局限性}血液中的亚群并评估它们对各种病原体的反应。以前，山羊 γδ T 细胞的比例是使用单克隆抗体 (mAb) 86D 确定的，我们在此展示的不会与所有 γδ T 细胞发生反应，从而低估了它们对淋巴细胞群的贡献。使用与 TCRδ 恒定区反应的 mAb，我们发现血液中 γδ T 细胞的比例不显着低于 CD4 或 CD8 T 细胞的比例，并且在 6 个月后不会随着年龄的增长而减少。表达 WC1 的 γδ T 细胞占总 γδ T 细胞的约 20% 至 85%。通过 mAb 染色，其中不到一半被分类为 WC1.1 ⁺或 WC1.2 ^{+ ，因此表明存在第三个主要 WC1 +}人口。我们发现，幼稚 γδ T 细胞在用钩端螺旋体或副结核分枝杆菌(MAP) 抗原刺激的 PBMC 培养物中增殖比在对照培养基培养物中或在用牛分枝杆菌BCG 抗原刺激的培养物中增殖更多，并且响应的 γδ T 细胞包括WC1 ⁺和 WC1 ^-电池。在 WC1 ^- γδ T 细胞而非 WC1 ⁺细胞的体外 PMA/离子霉素刺激的培养物中产生 IL-17 和 IFNγ。在钩端螺旋体或 MAP 的长期培养中，WC1 ^-和 WC1 ⁺细胞均增殖但只有 WC1 ^-γδ T 细胞产生 IL-17。总之，山羊在 PBMC 中有大量的 WC1 ^-和 WC1 ⁺ γδ T 细胞，在 6 个月后不会随着动物年龄的增长而减少；这两个群体都以幼稚细胞对细菌抗原作出反应，但在这些培养物中，只有 WC1 ^- γδ 细胞产生 IL-17 和 IFNγ。