小鼠γδ T细胞亚群在不同组织器官的分布特性及在感染后的变化

Distinct distributions of mouse γδ T cells in various tissues and changes after infection

目的:关注不同γδT细胞亚群在各组织器官的分布特点及在鼠伤寒沙门氏菌肠道感染中的变化,为探讨γδT细胞组织学分布的生理学意义和在感染性疾病中的作用提供依据和新的思路。方法:采用流式细胞术与PCR技术检测胸腺、脾脏、淋巴结、肝脏、皮肤以及小肠上皮内淋巴细胞中γδT细胞及其不同亚群的比例;通过PMA与离子霉素体外刺激,流式细胞术检测不同组织γδT细胞分泌细胞因子IFN-γ与IL-17a的差异;通过灌胃建立鼠伤寒沙门氏菌肠道感染模型,流式细胞术检测肝脏与小肠上皮内淋巴细胞中不同γδT细胞亚群比例的变化。结果:γδT细胞富含于小肠上皮内、皮肤与肝脏中,而在胸腺、脾脏与淋巴结中比例较低。不同亚群在各组织器官中的分布存在较大差异,皮肤主要存在Vγ5+γδT细胞亚群,小肠中主要存在Vγ1+、Vγ4+与Vγ7+γδT细胞亚群。肝脏γδT细胞主要分泌IL-17a,而小肠上皮内γδT细胞主要分泌IFN-γ。在鼠伤寒沙门氏菌肠道感染时,小肠上皮内γδT细胞的比例明显升高,其中Vγ1+γδT细胞比例升高更为显著;肝脏总γδT细胞比例无显著变化,但Vγ1+γδT细胞比例降低,Vγ4+γδT细胞比例明显升高。结论:γδT细胞富含于小肠、皮肤与肝脏中,且其不同亚群具有组织分布特异性。不同组织的γδT细胞产生细胞因子的能力存在较大差异。鼠伤寒沙门氏菌感染时,小肠与肝脏γδT细胞亚群的分布变化也存在较大差异。

Objective： The study focuses on the distinct distributions of γδ T cells in various tissues and the changes after Salmonella typhimurium infection,and attempts to explore the physiological significance of γδ T cell distribution and the role of γδ T cells in infectious diseases. Methods： Flow cytometry and PCR technique were used to detect the proportion of different γδ T cell subsets among thymus,spleen,lymph nodes,liver,skin,and intestinal intraepithelial lymphocytes. Flow cytometry was applied to detect the secretion of IFN-γ and IL-17 a. The changes of various γδ T cell subsets in liver and intestinal intraepithelial lymphocytes were analyze after Salmonella typhimurium infection. Results： γδ T cells were rich in the intestinal epithelium,skin and liver,but poor in the thymus,spleen and lymph nodes. The distribution of different subsets was quite dissimilar. Vγ5^＋γδ T cells chiefly existed in skin,and Vγ1^＋,Vγ4^＋,Vγ7^＋γδ T cells largely existed in small intestine. γδ T cells in liver mainly secreted IL-17a; however,γδ T cells in intestinal intraepithelial secreted IFN-γ. After infection by Salmonella typhimurium,the proportion of γδ T cells in intestinal intraepithelial increased significantly,particularly Vγ1^＋γδ T cells. In Liver,there was no significant change of total γδ T cell ratio,but the ratio of Vγ1^＋γδ T cells reduced,Vγ4^＋γδ T cells raised. Conclusion： γδ T cells are rich in the intestinal epithelium,skin and liver. The distribution of different subgroups has specificity. There are large differences in the ability of cytokine secretion among various subgroups ofγδ T cells. The distribution of γδ T cell subgroups in small intestine and liver changes during Salmonella typhimurium infection.