雷帕霉素对同种移植耐受模型CD4+CD25+ T细胞活性的影响

目的：研究雷帕霉素（Rapa）对同种移植耐受个体CD4^＋CD25^＋ T细胞体内负免疫调节作用的影响.方法：建立同种皮肤移植模型, 受体鼠术前预输注供体鼠脾细胞, 术后给予环孢素A（CsA）进行耐受诱导.移植后第14天提取耐受诱导模型鼠的T细胞, 经不同浓度Rapa和/或IL-2体外处理后, 混合淋巴细胞反应（MLR）确定T细胞特异增殖水平;流式细胞术（FCM）检测CD4^＋CD25^＋ T细胞比例变化;RT-PCR检测Foxp3 mRNA表达情况;ELISA检测细胞培养不同时间后上清中IL-10的变化.然后将Rapa和/或IL-2处理的T细胞过继转移给同种移植后的BALB/c-SCID鼠, 观察移植物存活状态.结果：CsA加供体脾细胞预先注射可明显延长小鼠移植皮片的存活期（P＜0.05）;移植耐受状态的T细胞经Rapa和/或IL-2体外处理后CD4^＋CD25^＋ T细胞比例升高、增殖水平明显降低、 Foxp3表达量明显增加;过继转输给同种移植SCID鼠后, 其移植皮片存活时间显著延长（P＜0.05）.结论：Rapa可体外扩增耐受诱导模型中CD4^＋CD25^＋ T细胞, 使CD4^＋CD25^＋ T细胞相关的Foxp3和IL-10明显升高, 过继免疫后, 小鼠同种移植物存活时间明显延长, 而低浓度IL-2可以协同Rapa的这一作用.

Effect of Rapamycin on CD4+CD25+ regulatory T cells in allo-transplantation tolerance model

AIM: To study the effect of Rapamycin(Rapa) on CD4 CD25 regulatory T cells in allo-transplantation tolerance model. METHODS: The model of skin allo-transplantation was established. The recipient BALB/c mice were injected with allogeneic donor spleen cells from B6 on the day before grafting and with cyclosporine(CsA) after transplantation. T cells were purified on the day 14 from the tolerant group and cultured with Rapa and/or IL-2 in different concentrations in vitro. Mixed lymphocyte reaction (MLR) was used to analyze the specific recall reaction of T cells. Percentages of CD4 CD25 regulatory T cells were examined by flow cytometry (FCM). The expression of Foxp3 mRNA was measured by RT-PCR, and the level of IL-10 in supernatant of T cells cultured in vitro was determined by ELISA. BALB/c-SCID mice underwent allo-transplantation were given adoptive transfer of T cells treated with Rapa and/or IL-2, then the survival conditions of the grafted skin were observed daily. RESULTS: CsA plus donor splenocyte injection can prolong allograft of BALB/c significantly(P<0.05). The number of CD4 CD25 regulatory T cells and the expression of Foxp3 mRNA for T cell in the tolerant group treated with Rapa and/or IL-2 were obviously increased. Adoptive transfusion of T cells from tolerant mice treated with IL-2/Rapa obviously prolonged the allograft survival time in allografted-SCID mice. CONCLUSION: Rapa can increased the ratio of CD4 CD25 regulatory T cells in vitro and prolonged the graft survival time obviously after adoptive immunity, and these effects are enhanced by low-dose of IL-2.