目的:研究肿瘤浸润树突状细胞（tumorinfiltrating dendritic cell，TIDC）及脾脏树突状细胞（splenic dendritic cell，SDC）表面B7H1、B71、B72分子的表达情况；探讨封闭TIDC及SDC表面B7H1分子对其介导T细胞免疫功能的影响。方法： CD11c磁珠阳性分选法提取荷瘤小鼠的TIDC及SDC，流式细胞术检测其表面B7H1、B71、B72分子的表达情况。TIDC及SDC作为刺激细胞，脾脏T细胞作为反应细胞行混合淋巴细胞反应，同时加入B7H1抗体或其对照抗体，XTT比色法检测T细胞增殖指数，ELISA法检测T细胞分泌IL10的量。〖HT5W〗结果：〖HT5"SS〗B71及B72分子在TIDC表面的表达水平显著低于SDC（P<001）；B7H1分子在TIDC及SDC表面皆中度表达，表达水平无明显差异（P>0.05）。TIDC刺激T细胞增殖能力显著低于SDC，且诱导T细胞分泌更多的IL10。封闭DC表面B7H1分子后，TIDC刺激T细胞增殖能力显著提高（P<0.01），且诱导T细胞分泌IL10的量明显减少（P<0.01）；SDC刺激T细胞增殖能力及诱导T细胞分泌IL10的量无明显变化（P>0.05）。结论：封闭DC表面的B7H1分子能显著提高TIDC活化T细胞的能力，可能解除TIDC介导的肿瘤免疫抑制

Objective: To explore the expression of B71, B72 and B7H1 on tumorinfiltrating dendritic cells (TIDC) and on splenic dendritic cells (SDC) , and to investigate TIDCmediated and SDCmediated Tcell function after blocking B7H1 expression in these dendritic cells. Methods: The TIDCs and SDCs were isolated from tumorbearing mice using antimouse CD11c magnetic beads. The expression of B71, B72 and B7H1 on TIDC and SDC was analyzed using flow cytometer. T cells were cocultured with TIDCs or SDCs for the mixed lymphocyte reaction (MLR), and monoclonal antibodies to B7H1 or the isotype control antibodies were added to the MLR cultures. Tcell proliferation was assessed using XTT method and the secretion of IL10 was detected using ELISA. Results: B71 and B72 positive TIDCs were significantly less than SDCs (P<0.01). B7H1 was moderately expressed on both TIDCs and SDCs (P>0.05). Tcell proliferation stimulated by TIDCs was weaker than that stimulated by SDCs; T cells produced more IL10 after TIDCs stimulation than after SDCs stimulation（P<0.01）. After blocking B7H1 on DCs, TIDCs showed a stronger stimulating ability on T cell proliferation compared with control antibodies, while SDCs did not have significant effect on T cell proliferation and production of IL10. Conclusion: Blocking B7H1 on TIDCs can significantly enhance their ability to activate T cells, and may elimilate TIDCmediated tumor immunosuppression.

复旦大学附属华山医院科研基金\[No.145\]