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初步探讨胃癌中异常增高的调节性T细胞(Treg)发挥免疫抑制的作用机制。利用多参数流式细胞术检测胃癌肿瘤局部CD4+CD25+Foxp3+Treg的Foxp3和环氧合酶2(COX-2)表达强度。CFSE增殖实验检测不同Foxp3表达强度的Treg对效应性T细胞的增殖抑制作用。在Treg与效应性T细胞共培养体系中加入COX-2抑制剂和前列腺素E2(PGE2)拮抗剂,观察PGE2的分泌水平以及Treg其对效应性T细胞的增殖抑制。结果发现,癌旁淋巴结和肿瘤浸润淋巴细胞(TIL)中Treg的Foxp3表达强度显著高于外周血(P<0.05);高表达Foxp3的Treg具有更强的抑制活性(P<0.05)。胃癌微环境中TregCOX-2表达强度与Foxp3表达强度显著相关(r=0.675,P<0.05)。应用COX抑制剂处理发现能阻断Treg分泌PGE2,COX抑制剂和PGE2拮抗剂均能降低Treg对效应T细胞增殖的抑制作用(P<0.05)。这表明胃癌局部高表达Foxp3的Treg具有较强的免疫抑制活性,COX-2-PGE2-EP2/EP4通路可能为胃癌微环境中Treg抑制效应T细胞增殖的机制之一。
Preliminary study of gastric cancer abnormally increased regulatory T cells (Treg) play an immunosuppressive mechanism. The expression of Foxp3 and cyclooxygenase 2 (COX-2) in CD4 + CD25 + Foxp3 + Tregs of gastric cancer were detected by multi-parameter flow cytometry. CFSE proliferation assay was used to detect the proliferation of effector T cells induced by Tregs with different expression of Foxp3. COX-2 inhibitor and prostaglandin E2 (PGE2) antagonist were added into the Treg-effector T cell co-culture system to observe the secretion of PGE2 and the inhibitory effect of Treg on the proliferation of effector T cells. The results showed that Foxp3 expression of Treg in adjacent non-cancerous lymph nodes and tumor-infiltrating lymphocytes (TIL) was significantly higher than that in peripheral blood (P <0.05). Tregs highly expressing Foxp3 had stronger inhibitory activity (P <0.05). The expression of TregCOX-2 in gastric cancer microenvironment was significantly correlated with the expression of Foxp3 (r = 0.675, P <0.05). Application of COX inhibitor treatment can block the Treg secretion of PGE2, COX inhibitor and PGE2 antagonist can reduce Treg on effector T cell proliferation (P <0.05). This suggests that Tregs with high expression of Foxp3 in gastric cancer have strong immunosuppressive activity, and that COX-2-PGE2-EP2 / EP4 pathway may be one of the mechanisms of Tregs inhibiting effector T cell proliferation in gastric cancer microenvironment.