重症甲型H1N1流感γδT细胞活化促IL-17高表达的调控机制研究

The mechanisms that influenza A/H1N1 virus induces lung injury are complex. Our previous studies have demonstrated that IL-17 response mediates acute lung injury induced by influenza A/H1N1 virus [Cell Research (2011) :1-11]. But the source and regulatory mechanism of over-production of IL-17 have not been demonstrated yet. Recently, we observed elevated IL-17 concentration and increased number of γδT lymphocytes in bronchoalveolar lavage fluid of severe influenza A/H1N1 virus infected mice model. In addition, γδT lymphocytes are the main producers of IL-17 after Escherichia coli (E. coli) infection. Recent studies have shown that some human as well as mouse γδT cells express functional TLRs such as TLR2, supporting a role in early responses to bacterial and microbial infections. The presence of IL-23 strongly enhances the effect of TLR2 on γδT cells. So we hypothesize that in severe mice model with influenza A/H1N1 virus infection, IL-17 may be over-produced by γδT lymphocytes via TLR2，and the production is regulated by IL-23 signaling pathway. In order to confirm this hypothesis, we are going to (1) detect the relationship between IL-17 production and and dynamic changes of IL-17+ γδT in the lungs of mice infected with influenza A/H1N1 virus, (2) study the regulatory role of IL-23 signal pathway in the over-production of IL-17 by γδT lymphocytes, and（3）investigate the mechanism that IL-17+γδ T cell mediates acute lung injury with influenza A/H1N1.This study can help us understand more about the mechanisms of IL-17 over-production and regulation in the acute lung injury by influenza A H1N1 virus, and the development of new therapeutic approaches against IL-17 production pathway could be possible.

甲型H1N1流感（简称甲流）病毒引发肺损伤的免疫机制复杂，我们前期工作发现IL-17在甲流肺组织损伤中起重要作用，但IL-17高表达的调控机制未明。最新研究表明：依赖IL-23信号通路激活的γδ T细胞可能是细菌感染IL-17的主要来源。我们也发现甲流小鼠肺泡灌洗液中IL-17升高、γδ T细胞增多。由此提出假设：甲型H1N1流感病毒可通过TLR2激活γδ T细胞，并在IL-23信号通路的介导下引发IL-17的高表达，从而推动肺组织损伤。本项目拟通过研究甲流小鼠肺组织中IL-17+γδT细胞的动态变化、甲型H1N1病毒诱导肺组织γδ T细胞产生IL-17、 IL-23介导的信号通路对肺组织γδ T细胞产生IL-17的调控和IL-17+γδ 细胞在甲流肺损伤发生过程中的作用,来探讨重症甲流肺组织γδT细胞活化促IL-17高表达的调控机制。这一研究将为重症甲流的发病机制和免疫调节剂的研发提供新

起源于墨西哥和美国西部的2009年新型流感在全球范围内大流行引起高发病率和死亡率并持续影响人类的健康。在临床，抗病毒治疗药物种类很少，且病毒突变和不可预测性使得抗病毒治疗更加局限，我们急切的需要寻找新的病毒感染治疗药物。.本研究目的是调查H1N1流感病毒感染后γδT细胞及两个细胞亚群Vγ1和Vγ4细胞的分布动力学变化和功能。在早期H1N1流感病毒感染后γδT细胞及两个细胞亚群Vγ1细胞和Vγ4细胞的免疫作用。并进一步阐明γδT细胞分泌IL-17可能的机制及信号通路。我们通过滴鼻感染方式建立重症甲流感染小鼠模型，通过流式检测感染后1,3,7天肺脏γδT细胞和两个细胞亚群Vγ1细胞和Vγ4细胞表面IL-17A 的表达情况，经anti-TCR-γ/δ mAbs, anti-TCR-Vγ1 mAbs and anti-TCR-Vγ4 mAbs抗体干预后流感病毒感染小鼠生存率变化和炎症反应情况。IL-23和IL-1β与γδT细胞共培养经ELISA检测上清液中IL-17的浓度。该研究发现在H1N1流感病毒感染后肺组织γδT细胞比例显著上升，在感染早期γδT17细胞能迅速扩增并比Th17和Tc17细胞更早分泌IL-17，Vγ4细胞比例在感染后小鼠肺组织中显著升高并且是γδT17细胞的主要亚群。感染早期anti-TCR-γ/δ mAbsγδT和anti-TCR-Vγ4 mAbs抗体干预后通过减少分泌IL-17提高生存率并减少免疫病理损伤。IL-23和IL-1β能够刺激肺组织γδT细胞可能通过活化JAK-STAT 通路高分泌IL-17。该研究发现γδT细胞和两个亚群在流感感染时的主要作用，可能为免疫治疗提供新思路。.