小鼠派氏集合淋巴结T细胞活化和调节性T细胞的分析

目的： 通过对小鼠派氏集合淋巴结（PPs）、肠系膜淋巴结（MLNs）和腹股沟淋巴结（ILNs）的比较性研究，以分析PPs T细胞活化和调节性T细胞的功能特点。 方法： 无菌分离小鼠PPs、MLNs和ILNs，分别制备单个淋巴细胞悬液，运用流式细胞术结合荧光抗体染色技术来检测CD3+T细胞、CD3+CD4+辅助性T细胞和CD4+CD25＋调节性T细胞的比例；用多克隆刺激剂刀豆蛋白A（Con A）、佛波醇酯（PDB）和离子霉素（Ion） 刺激活化淋巴细胞，随后运用流式细胞术结合双色荧光抗体染色技术来检测T细胞早期活化标志CD69的表达水平。 结果： PPs内CD3+T细胞所占比例明显低于MLNs和ILNs，然而CD4+CD25＋调节性T细胞的比例明显高于MLNs和ILNs；在没有加入刺激剂的培养条件下，PPs来源的T细胞CD69的表达水平明显高于MLNs和ILNs来源的T细胞，MLNs来源的T细胞CD69的表达水平明显高于ILNs来源的T细胞；而在加入Con A或者单纯PDB的培养条件下，PPs来源的T细胞却表现出低反应性；在加入PDB＋Ion的培养条件下，3者来源的T细胞CD69的表达水平没有明显差别。 结论： PPs内CD3+T细胞所占比例较低，CD4+CD25＋调节性T细胞的比例较高，这可能是PPs整体T细胞低反应性的原因之一；PPs来源T细胞的高基础活化率可能与其不断接触小肠来源的食物和共生菌抗原有关；PPs来源T细胞选择性地对某些刺激剂表现出低反应性，提示这群细胞处于某种程度的无能状态。上述特征的生物学意义在于避免因为不断接受小肠来源的食物和共生菌抗原的刺激而发生病理性炎症的同时还保留对病原微生物抗原的应答。

Analysis of T cell activation and regulatory T cell derived from murine Peyer's patches

AIM: To explore the characteristics of T cell activation and regulatory T cells derived from murine Peyer's patches through comparative studies on Peyer's patches, mesenteric lymph nodes and inguinal lymph nodes. METHODS: Signal cell suspendsions were prepared from murine mesenteric lymph nodes (MLNs), the Peyer's patches (PPs) and inguinal lymph nodes (ILNs), respectively. The percentage of cell subpopulations such as CD3 T cells, CD3 CD4 helper T cells and regulatory T cells (Treg, CD4 CD25 ) were analyzed. Lymphocytes were activated by polyclonal stimulators such as concanavalin (Con A), phorbol 12, 13-dibutyrate (PDB) only, and PDB plus ionomycin (Ion). The expression of CD69 (the early marker of CD3 T cell activation) was measured by FACS. RESULTS: A lower ratio of CD3 T cells was seen in PPs than those in MLNs and ILNs. The ratios of CD3 CD4 T cells to CD3 T cells in PPs, MLNs and ILNs were almost the same. A higher rate of Treg was seen in CD4 T cells from the PPs as compared with those from MLNs and ILNs. A higher percentage of activated CD3 T cells derived from the PPs cultured without polyclonal stimulators were detected as compared to MLNs and ILNs, while lower responsiveness of CD3 T cells from the PPs stimulated by Con A was seen as compared with those from MLNs and ILNs. CONCLUSIONS: The lower rate of CD3 T cells as well as higher rate of Treg in PPs was due to its desensitization. The higher rate of basic activated state in CD3 T cells from the PPs indicated that the T cells were activated by enteric antigens in physiological conditions. The lower responsiveness of activation to some polyclonal stimulators probably reveals that the T cells are in a state of anergy. All the characteristics mentioned above contribute to prevent pathological inflammations and maintain tolerance to enteric antigens such as food proteins and commensal bacteria but simultaneously retain proper immune responses to pathogenic microbes.