Department of Pathogenic Microbiology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an 710061.
Institute of Infection and Immunity, Translational Medicine Institute, Xi'an Jiaotong University Health Science Center, Xi'an 710061.
Zhong Nan Da Xue Xue Bao Yi Xue Ban. 2023;48(9):1296-1303. doi: 10.11817/j.issn.1672-7347.2023.220633.
OBJECTIVES: The differentiation of CD4 T cells is regulated by a complex and fine signaling pathway composed of many molecules during immune response, and the molecular mechanism for regulating T-bet expression is unclear. Mediator complex subunit 1 (Med1) can combine with a variety of co-factors to regulate gene transcription, promote cell proliferation and survival, and affect invariant natural killer T cell (iNKT) development. This study aims to investigate the effect of Med1 on T cell development and CD4 T cell differentiation in immune response. METHODS: Mice with T cell-specific knockout of gene (Med1CD4cre, KO) were constructed and verified. The percentage and number of CD4 and CD8 T cells in thymus, spleen, and lymph nodes of KO mice and control (Con) mice (Med1CD4cre) were detected by flow cytometry. After 8 days of infection with lymphocytic choriomeningitis virus (LCMV), the percentage and number of CD4 T cells or antigen-specific (GP66) CD4 T cells, the percentage and number of Th1 cells (Ly6cPSGL1) in CD4 T cells or antigen-specific CD4 T cells were examined in the spleen of mice. Moreover, the fluorescence intensity of T-bet in CD4 T cells or antigen-specific CD4 T cells was analyzed. RESULTS: Compared with the Con group, the percentage and number of CD4 T cells and CD8 T cells in the thymus, CD4 T cells in the spleen and lymph nodes of the KO group showed no significant differences (all >0.05), but the percentage and number of CD8 T cells in the spleen and lymph nodes of the KO group were diminished significantly (all <0.05). After 8 days of infection with LCMV, there was no significant difference in the percentage and number of CD4 T cells or antigen-specific CD4 T cells in the spleen between the KO group and the Con group (all >0.05), while in comparison with the Con group, the percentage and number of Th1 cells in CD4 T cells or antigen-specific CD4 T cells, and the expression of T-bet in CD4 T cells or antigen-specific CD4 T cells were significantly reduced in the spleen of the KO group (all <0.05). CONCLUSIONS: Specific knockout of in T cells does not affect the development of CD4 and CD8 T cells in the thymus, but does affect the maintenance of peripheral CD8 T cells. In the immune response, gene deletion affects the expression of transcription factor T-bet, which in turn to reduce Th1 cell differentiation.
目的：CD4 T 细胞的分化受免疫反应中许多分子组成的复杂精细信号通路调控，而调节 T-bet 表达的分子机制尚不清楚。中介体复合物亚基 1（Med1）可以与多种共因子结合，调节基因转录，促进细胞增殖和存活，并影响固有自然杀伤 T 细胞（iNKT）的发育。本研究旨在探讨 Med1 对 T 细胞发育和 CD4 T 细胞分化的影响。
方法：构建并验证了 T 细胞特异性敲除基因（Med1CD4cre，KO）的小鼠。通过流式细胞术检测 KO 小鼠和对照（Con）小鼠（Med1CD4cre）胸腺、脾和淋巴结中 CD4 和 CD8 T 细胞的百分比和数量。在用淋巴细胞性脉络丛脑膜炎病毒（LCMV）感染 8 天后，检测小鼠脾中 CD4 T 细胞或抗原特异性（GP66）CD4 T 细胞的百分比和数量、CD4 T 细胞或抗原特异性 CD4 T 细胞中 Th1 细胞（Ly6cPSGL1）的百分比和数量，以及 CD4 T 细胞或抗原特异性 CD4 T 细胞中 T-bet 的荧光强度。
结果：与 Con 组相比，KO 组胸腺中 CD4 T 细胞和 CD8 T 细胞的百分比和数量、脾和淋巴结中 CD4 T 细胞的百分比和数量无显著差异（均>0.05），但 KO 组脾和淋巴结中 CD8 T 细胞的百分比和数量明显减少（均<0.05）。感染 LCMV 8 天后，KO 组与 Con 组脾中 CD4 T 细胞或抗原特异性 CD4 T 细胞的百分比和数量无显著差异（均>0.05），但与 Con 组相比，KO 组脾中 CD4 T 细胞或抗原特异性 CD4 T 细胞中 Th1 细胞的百分比和数量，以及 CD4 T 细胞或抗原特异性 CD4 T 细胞中 T-bet 的表达明显减少（均<0.05）。
结论：T 细胞中特异性敲除 基因不会影响胸腺中 CD4 和 CD8 T 细胞的发育，但会影响外周 CD8 T 细胞的维持。在免疫反应中，基因缺失影响转录因子 T-bet 的表达，进而减少 Th1 细胞分化。
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