通过降低甚至避免移植排斥反应延长异体皮肤存活时间对自体皮源不足的大面积烧伤救治尤为重要。BMSCs具有低免疫原性及免疫调节特性，但其免疫调节作用尚不足以完全抑制移植排斥反应。IDO被证实对效应T细胞具有促凋亡、抑增殖的作用，同时可诱导调节性T细胞产生。但BMSCs表达IDO受胞外微环境的影响，往往导致其对T细胞的调节能力降低甚至丧失。通过基因转染使BMSCs稳定高表达IDO能否增强其免疫调节能力值得深入研究。据此，本课题拟通过基因转染技术构建高表达IDO的BMSCs（IDO-BMSCs），在体外研究其对初始T细胞向Th17/Treg细胞分化的影响及机制，进一步将IDO-BMSCs输注小鼠体内，同时进行异体皮肤移植，观察IDO-BMSCs对移植排斥/耐受形成的影响。本研究有望为抑制甚至避免移植排斥反应寻求新的分子靶点及治疗方法，同时探索BMSCs作为细胞载体在移植排斥研究领域的应用。

Prolongation of skin allografts survival time by suppressing or avoiding the immune rejection is very important for the patients with extensive burns. Bone marrow-derived mesenchymal stem cells(BMSCs) have the low immunogenicity and immunoregulatory capacity. However, the immunoregulatory capacity of BMSCs couldn't inhibit graft rejection totally. It has been verified that indoleamine 2, 3-dioxygenase(IDO) could promote apoptosis and inhibit proliferation on effector T cell. The expression of IDO by BMSCs is affected by a variety of extracellular factors, which often decrease or abolish the immunoregulatory capacity of BMSCs on T cell. It has great significance for further research the effect of stable high expression of IDO by gene transfection in BMSCs on its immunomodulatory ability. Therefore, IDO gene transfected BMSCs(IDO-BMSCs) will be built in this research. The effect and mechanism of IDO-BMSCs on naive T cells differentiation to Th17/Treg cells will been researched in vitro. Furthermore, the recipient mouse will accepted both IDO-BMSCs an allo-skin transplantation, in order to verifying the effect of IDO-BMSCs on immune rejection. This research will provide new molecule targets and therapies. Meanwhile, explore application of BMSCs as trager in the field of transplant rejection.