iPS细胞由来调节性DC的分化诱导及其免疫调节作用机制的解析

调节性树突状细胞(Regulatory Dendritic Cell,rDC)因其在维持免疫耐受方面的重要作用，被认为可以用来治疗自身免疫性疾病及移植免疫排斥。体外成功诱导rDC的研究已有报道,但是用骨髓或血液单核细胞诱导rDC的不足在于：获得的rDC数量少且性质不稳定，限制了rDC用于临床治疗的研究。为突破这个瓶颈，并根据不同组织来源、不同条件下诱导的rDC是通过不同的机制来调节免疫应答，抑制器官炎性损害的理论，我们设想是否可以利用诱导性多能干细胞（Induced Pluripotent Stem，iPS）作为源细胞，诱导得到大量、稳定、高效的rDC？我们前期研究已知iPS由来的经典DC其纯化程度远高于骨髓细胞由来的经典DC。因此，我们计划采用iPS细胞+不同基质细胞+不同诱导刺激引物的组合来探索iPS细胞向rDC的分化诱导，并通过一系列体内、外实验来检验其免疫调节功能，解明其作用机制。

Dendritic cells (DCs) have several functions in innate and adaptive immunity as the most potent antigen-presenting cells. In addition, there is increasing evidence that DCs in situ induce antigen specific unresponsiveness or tolerance in immune system,central lymphoid organs and in the periphery, which were designated as regulatory DCs (rDCs). The mechanisms of rDCs to negative regulate the immune response were proved to inducing regulatory T cells or inducing T cells anergy or secreting immuregulation cytokines. Thus, the usage of rDCs was considered as a promising cell therapeutic strategy for autoimmune diseases and transplantation. . Now, DCs for transfer therapy are generated by in vitro differentiation of peripheral blood monocytes of the patients. However, there is a limitation in the number of available monocytes, and the potential of DC-differentiation in monocytes varies depending on the blood donor. Induced pluripotent stem (iPS) cells possess both pluripotency and infinite propagation capacity. Thus we consider iPS cells to be an ideal source for rDCs to be used in immunotherapy. . Generation and characterization of conventional DCs (cDCs) derived from mouse and human iPS cells were reported by Senju etc. The iPS cell derived cDCs (iPS-cDCs) possessed the characteristics of cDCs including the capacity of T cell-stimulation, antigen-processing and presentation, and cytokine production. Whereas, there are no any reports of the generation rDCs from iPS cells, which we consider is potential useful for the treatment of autoimmune diseases. . Therefore, in the present study, we plan to generate rDCs from mouse iPS cells, using the protocol that iPS cells cultured on the bone marrow stromal cells (OP9 cells) or spleen stromal cells layer, content with granulocyte/macrophage colony stimulating factor (GM-CSF),interleukin (IL)-10 and transforming growth factor(TGF)-beta. And then, we plan to analyze how the generated iPS-rDCs play the immune regulatory functions and it's mechanisms in vitro and in vivo experiments.