对早期凋亡细胞的吞噬抑制T淋巴细胞活化的实验研究

目的:研究早期凋亡细胞及吞噬早期凋亡细胞的巨噬细胞对T淋巴细胞活化的影响。方法:体外以紫外线照射,诱导出早期凋亡的Jurkat细胞;建立早期凋亡细胞的吞噬模型;ELISA法分析早期凋亡细胞对LPS刺激下巨噬细胞分泌细胞因子的影响及在早期凋亡细胞和吞噬了早期凋亡细胞的巨噬细胞干预下,ConA刺激T淋巴细胞活化后CD69、CD25、CD71表达的变化。结果:巨噬细胞吞噬了早期凋亡细胞后,抑制性细胞因子(TGF_β1)的分泌明显上调,并且在一定程度上抑制了ConA刺激下的T淋巴细胞活化;具体表现为CD69、CD25、CD71等T淋巴细胞活化标志的表达受到明显抑制。当加入TGF_β1中和抗体后,这种抑制作用消失。结论:巨噬细胞吞噬了早期凋亡细胞后抑制ConA刺激下的T淋巴细胞CD69、CD25、CD71的表达,这种抑制作用依赖于的TGF_β1分泌增强。

Phagocytosis of viable apoptotic cells inhibits the activation of T lymphocytes

AIM: To investigate whether viable apoptotic cells and phagocytosis of them affect the activation of T lymphocytes. METHODS: Ultraviolet irradiation was used to induce apoptotic cells in vitro and the model of phagocytosis of these cells was established. Cytokine TGF_β1 was detected by ELISA. The rate of apoptotic cells and phagocytosis of them were assessed by flow cytometry. Furthermore, flow cytometry was also employed to examine the expression of activation signs, such as CD69, CD25, CD71, of T lymphocytes under the intervention of apoptotic cells and macrophage which ingested apoptotic cells, to reflect whether the apoptotic cells and the phagocytosis of these cells could influence the activation of lymphocytes stimulated by Con A. RESULTS: Ingestion of apoptotic cells increased TGF_β1 secretion. Only the macrophages that had ingested apoptotic cells could suppress the activation of lymphocytes. The expression of the markers of lymphocytes activation such as CD69, CD25, CD71 had been restrained. These inhibition effects were abolished by monoclonal anti-TGF_β1 antibody. CONCLUSION: The macrophages that have ingested apoptotic cells inhibit expression of CD69, CD25 and CD71 of T lymphocytes stimulated by ConA. This effect is dependent on the increase in TGF_β1 secretion in local site.