CD300f高表达的受者源性树突状细胞诱导同种移植免疫耐受

The tolerogenic dendritic cell (tol-DC) is considered to be the best choice to induce specific immune tolerance in organ transplantation. It has been proved that a variety of tol-DCs can regulate immune response,and inhibit the rejection in animal models, but it is still difficult to achieve the ideal tolerogenic condition.How to improve the property of tol-DC is the key of the research in transplant immunity.According to the latest research and our preliminary exploration, we found that CD300f is the key molecule expressed on the surface of DCs to inhibit immune response,and blocking CD300f activation will enhance DC immune activity. In addition, the overexpression of CD300f in DC can inhibite TLR4-NF-kappa B signal pathy to acquire the immature DC.Therefore,we think the up-regulation CD300f expression in DC is likely to significantly improve the immune tolerance ability of tol-DC.This project intends to adopt recipient-derived DCs,which are loaded with donor derived apoptosis spleen cell, and raised up CD300f expression at the same time, in order to acquire donor-specific immune tolerance.In vitro,its characteristic and mechanism of induction of immune tolerance are tested.In vivo, the recipient mice are treated i.v. with CD300f-tol-DCs or non tol-DCs prior to kidney transplantation.Then,it is observed of the feasibility and the specific mechanism of the induction of immune tolerance. The project will provide the theory basis for its application into clinical immune tolerance.

致耐受性树突状细胞（tol-DC）被认为是器官移植中诱导特异性免疫耐受的最佳选择。迄今已证明，多种不同tol-DC在动物实验中显示发挥免疫调节，降低排斥反应的作用，但仍难以达到完全耐受。如何提高tol-DC致耐受能力是研究的重点。根据最新研究及我们前期探索，发现CD300f是DC表面表达的调控DC抑制性免疫应答的关键分子，阻断CD300f作用会增强DC免疫激活活性，而活化DC中CD300f表达可通过抑制TLR4-NF-κB诱导DC不成熟。因此大幅上调CD300f表达极有可能显著提高tol-DC的免疫抑制能力。本项目拟采用受体来源DC，负载供体凋亡脾细胞抗原同时上调CD300f的表达，以获得抗原特异性免疫耐受性DC。检测其诱导免疫耐受的特性和机制。并于大鼠肾移植前输注于受体内，观察其诱导免疫耐受的可行性及检测具体机制。项目如成功实施，将为临床诱导免疫耐受提供理论依据。

致耐受性树突状细胞（tol-DC）被认为是器官移植中诱导特异性免疫耐受的最佳选择。迄今已证明，多种不同tol-DC在动物实验中显示发挥免疫调节，降低排斥反应的作用，但仍难以达到完全耐受。如何提高tol-DC致耐受能力是研究的重点。国外研究提示CD300f是DC表面表达的调控DC抑制性免疫应答的关键分子。本项目先构建CD300f腺病毒载体，制备合成腺病毒颗粒，转染DC，能显著上调CD300f表达。检测上调CD300f的DC特征，发现其细胞凋亡无明显改变，而细胞表面分子CD80，CD86，CD83，MHCⅡ表达均下降，Th1型细胞因子表达下降，Th2型细胞因子表达上调，初步说明具有抑制免疫应答能力。再将高表达CD300f-DC同淋巴细胞混合反应，发现可以抑制淋巴细胞增殖，促进淋巴细胞凋亡，抑制Th1型细胞因子的表达，上调Th2型细胞因子的表达，以及促进T细胞分化为调节性T细胞。动物实验中，利用大鼠肾移植模型，移植前输注受体来源的负载供体脾抗原的CD300f-DC，发现可以抑制排斥反应，减轻免疫细胞浸润，减少细胞凋亡，下调间质纤维化。因此，上调DC中CD300f表达能在一定程度上获得tol-DC，从而为制备临床切实可行的耐受性树突状细胞提供基础。