过表达SOCS1分子的树突状细胞诱导T细胞无能及其对小鼠移植物的免疫保护作用

The immunoprotection of transplant mice allograft by suppressor of cytokine signaling 1 gene - modified dendritic cells induces T cell anergy

目的探讨过表达细胞因子信号抑制因子1（SOCS1）的树突状细胞（DC）对T细胞功能的影响和对小鼠移植物的免疫保护作用及其机制。方法通过腺病毒将SOCS1基因转入小鼠DC，观察SOCS1基因修饰DC表型及功能变化；建立小鼠同种异体胰岛移植模型，各组受体于术前24 h分别输入DC、DC-SOCS1细胞或磷酸盐缓冲液（PBS），术后观察各组移植胰岛存活时间，并于术后第7天检测受体糖耐量、移植胰岛的病理学改变、脾脏及引流淋巴结内T细胞亚群及细胞因子的含量变化。结果DC-SOCS1表诱导T细胞的增殖能力明显弱于DC（19.9%比51.1%，P〈0.05）。DC-SOCS1组移植胰岛平均生存时间为（37.00±2.19） d，较空白组[（20.00±0.55） d，P=0.008]及DC组[（10.00±0.45） d，P=0.001]均显著延长。移植术后第7日，DC-SOCS1组受体较其他组对葡萄糖的耐受良好，组织学结果表明DC-SOCS1组受体胰岛移植物活性更优。DC-SOCS1组小鼠脾脏内辅助性T细胞（Th1）及细胞毒性T细胞（Tc1）的含量[（9.92±1.57）%，P=0.027]、脾脏内CD4＋细胞[（17.77±2.80）%，P=0.007]、CD8＋细胞[（14.92±2.18）%，P=0.004]及引流淋巴结内的CD4＋淋巴细胞[（26.00±2.02）%，P=0.034]明显减少。结论SOCS1基因抑制DC成熟，诱导T细胞无能并保护胰岛移植物。

ObjectiveTo study the regulation of high expression of suppressor of cytokine signaling 1 （SOCS1） molecule in dendritic cells （DC）, and to verify the effect of DC-SOCS1 on T cell function and allografts immune protective effects in vitro and in vivo.MethodsDC were modified with high affinity replication-defective adenoviral vector Ad5F35 over-expressing SOCS1. The phenotype of transduced mature DC and the function were analyzed, and the mechanism of inducing donor-specific CD4＋ T cells hyporesponsiveness was explored. The mouse allogenic islet transplantation model was established, and 24 h prior to transplantation each recipient mouse was given DC cells, DC-SOCS1 cells or equal amount of phosphate buffer （PBS）, named DC group, DC-SOCS1 group and control group respectively. The survival of islet grafts of transplanted recipients was observed, and on the day 7 and the rejection day post transplantation, the islet graft glucose tolerance, pathological changes, the percentage of T cell subsets in the spleen and draining lymph nodes as well as related cytokines were observed. The possible associated mechanisms of SOCS1 gene-modified mature DC mitigating immune rejection and inducing transplant tolerance in vivo were explored.ResultsGenetic modified Ad5F35 dramatically increased the transduction efficiency of DC compared to regular Ad. The experimental data demonstrated there was a tendency that DC overexpressing SOCS1 can induce DC low down the express of MHC and costimulatory molecules, potentiate the ability of DC-SOCS1 to induce donor specific T cell anergy in mixed lymphocytes reaction （MLR） assay. DC-SOCS1 significantly prolonged the survival time of the islet allograft with a median survival time of （37.00±2.19） days, which is significantly longer than control [（20.00±0.55） d, P=0.008] and DC group [（10.00±0.45） d, P=0.001]. Flow cytometric analysis revealed that the DC-SOCS1 dramatically reduced the population of Th1 and Tc1 [（9.92±1.57）%, P=0.027], CD4 [（17.77±2.80）%, P=0.007] and CD8 [（14.92±2.18）%, P=0.004] in spleen lymphocytes compared to control group and DC group on day 7, and a reduction of CD4 [（26.00±2.02）%, P=0.034] was observed in draining lymph nodes compared to DC group.ConclusionSOCS1 genetic modification efficiently confers mDC with low express of MHC and costimulatory molecules, and allows them to induce T cell hyporesponsiveness in vitro. The DC-SOCS1 pretreated recipients exhibit immune tolerance and prolong islet allograft survival in vivo.