摘要目的 研究B7H4在人骨髓源间充质干细胞(HBMSC)介导的免疫抑制中的作用.方法 应用RT-PCR和流式细胞术分别检测B7H4在HBMSC上的表达;应用抗体阻断实验分析B7H4在HBMSC对PHA活化下T细胞活化、增殖及周期影响中的作用;Transwell细胞培养系统分析HBMSC对T细胞增殖抑制的作用方式.结果 HBMSC上高表达免疫负性调控分子B7H4.应用B7H4单克隆抗体(单抗)阻断HBMSC上B7H4的表达,T细胞增殖刺激指数(SI)在抗体阻断组为27±17,与未阻断组(15±8)相比差异有统计学意义(P＜0.01);T细胞周期中G0/G1期和S期细胞数量分别为(85.6±9.9)%和(5.8 4±3.2)%,与未阻断组[(95.8±9.9)%,(2.3±2.2)%]相比差异有统计学意义(P值均＜0.05),B7H4单抗明显减弱HBMSC对T细胞增殖的影响.将HBMSC与T细胞进行物理分隔后,T细胞增殖SI为53±5,与直接接触组(15±3)相比差异有统计学意义(P＜0.01).结论 HBMSC高表达B7H4分子,并在HBMSC介导的T细胞增殖抑制中发挥重要作用.

abstractsObjective To investigate the effects of B7H4 on human bone marrow mesenchymal stem cells(HBMSC)mediating immune suppression.Methods The expression of the negative immunoregulatory factor B7H4 on HBMSC were analyzed by RT-PCR and flow cytometry(FCM),respectively.The blocking experiment was used to detect the effects of B7H4 on HBMSC mediating suppression on PHA induced T cell activation.proliferation and cell cycle.HBMSC inhibiting T cell proliferation was examined by transwell cell culture system.Results B7H4 was highly expressed on HBMSC.Blocking the B7H4 expression by B7H4 mAb significantly attenuated the inhibitory effects of HBMSC on T cell proliferation.Compared with that of the unblocking group,T cell stimulator index(SI)of the B7H4 blocked group was significantly increased (53±5 vs 15±8,P＜0.01)and the inhibitory effects of HBMSC on T cell cycle were weakened significantly through down-regulating the cell number in G0/G1 phase[(85.6± 9.9)%vs(95.8±9.9)%]and up-regulating those in S phase[(5.8±3.2)%vs(2.3±2.2)%,P＜0.05].The suppressive effects of HBMSC on T cell proliferation were significantly weakened after separating HBMSC from T cells by transwell cell culture system.Compared with the cell to cell contact group,T cell SI was significantly increased(27 ±17vs15±3,P＜0.01).Conclusion HBMSC highly express B7H4,which plays an important role in the suppressive effects of HBMSC on T cell proliferation.