Ⅰ型NKT细胞通过调节树突状细胞功能参与哮喘小鼠Th2反应

TypeⅠnatural killer T (NKT) cells induce dendritic cell (DCs) maturation and subsequently enhance adaptive immune response. In our previous study, it was found that lung typeⅠNKT cells were activated and lung DCs showed a mature phenotype with high expression levels of maturation markers of DCs, such as CD80, CD86, MHCⅡ and cell adhesion molecule CD40, while the function of typeⅠNKT cells were inhibited, lung DCs showed an immature phenotype with low expression levels of maturation markers and cell adhesion molecule. TypeⅠNKT cells can enhance Th2 immune response induced by peptide antigen in a mouse model of asthma. Thus, it is hypothesized that typeⅠNKT cells may induce Th2 immune response through modulating function of dendritic cells in a mouse model of asthma. For this purpose, we use wildtype BALB/c mice, Jα18-/- mice and CD40-/-BALB/c mice to establish a mouse model : (1) To investigate the effect of activated typeⅠNKT cells on Th2 immune response, phenotype and function of dendritic cells in a mouse model of asthma. (2) To investigate the effect of DCs modulated by typeⅠNKT cells on Th2 immune response in a mouse model of asthma. (3) In OVA sensitized and challenged mice with or without dendritic cell depletion, to investigate the effect of activated type I NKT cells on Th2 immune response in a mouse model without dendritic cells. (4) To investigate the mechanism that activated typeⅠNKT cells regulate DCs, which may perform through CD40-CD40L interaction following the activation of transcription factors NF-κB and p38MAPK pathway in DCs. The aim of this study is to investigate that activated typeⅠNKT cells induce phenotype and function maturation of dendritic cells and subsequently augment Th2 immune response and involve in allergic airway inflammation in a mouse model of asthma.

Ⅰ型NKT细胞促进树突状细胞（DCs）成熟增强获得性免疫反应，且我们的初步观察发现哮喘小鼠Ⅰ型NKT细胞活化时DCs为成熟表型，功能抑制时DCs为不成熟表型；由于Ⅰ型NKT细胞增强肽类抗原诱导的哮喘小鼠Th2反应，因此假设Ⅰ型NKT细胞通过调节DCs的功能参与哮喘小鼠Th2反应。为此，以野生型、Jα18-/-和CD40-/-BALB/c小鼠建立动物模型：（1）观察活化的Ⅰ型NKT 细胞对哮喘小鼠Th2反应、DCs表型和功能的影响；（2）观察经活化的Ⅰ型NKT细胞调节的DCs对哮喘小鼠Th2反应的影响；（3）以卵清蛋白致敏和激发去除和未去除DCs的小鼠，观察活化的I型NKT细胞对缺乏DCs的小鼠Th2反应的影响；（4）初步观察Ⅰ型NKT细胞调节DCs功能的机制。探讨Ⅰ型NKT细胞通过促进DCs的表型和功能成熟诱导哮喘小鼠Th2反应，进而参与气道炎症的形成。

本项目探讨Ⅰ型NKT细胞（iNKT细胞）是否通过促进树突状细胞（DCs）的表型和功能成熟参与哮喘小鼠Th2反应。为此：以野生型和CD1d-/--BALB/c小鼠建立动物模型：（1）观察Ⅰ型NKT 细胞对哮喘小鼠Th2反应的影响；（2）观察Ⅰ型NKT 细胞对哮喘小鼠树突状细胞表型和功能的影响；（3）初步观察Ⅰ型NKT细胞通过CD40L调节树突状细胞的功能。结果发现：（1）α-半乳糖神经酰胺可以活化野生型BALB/c小鼠肺iNKT细胞，但小鼠没有产生气道炎症；卵清白蛋白（OVA）诱导哮喘小鼠产生气道炎症时，肺iNKT细胞活化；α-半乳糖神经酰胺活化肺iNKT细胞或过继转移iNKT细胞可以增强卵清白蛋白诱导的哮喘小鼠Th2炎症反应；以卵清白蛋白致敏和激发缺乏iNKT细胞的CD1d-/--BALB/c小鼠，发现缺乏iNKT细胞时小鼠Th2炎症反应减轻；（2）α-半乳糖神经酰胺活化肺iNKT细胞或过继转移iNKT细胞可以增强肺树突状细胞（LDCs）表面成熟标志和促炎细胞因子分泌水平，表现为MHCII、CD80、CD86和CD40表达水平明显增高，LDCs体外培养上清液促炎细胞因子明显增高，而缺乏iNKT细胞时LDCs表面成熟标志和促炎细胞因子分泌水平明显降低；存在OVA时，iNKT细胞诱导DCs免疫原性成熟，而缺乏OVA时，iNKT细胞诱导DCs耐受原性成熟；α-半乳糖神经酰胺活化iNKT细胞诱导LDCs表面分子CD206 和RELM-α表达水平明显增高；（3）α-半乳糖神经酰胺可以诱导iNKT细胞表面分子CD40L表达水平明显增高；LDCs与iNKT细胞共培养时，抗CD40L单克隆抗体可以明显降低LDCs表面成熟标志和促炎细胞因子分泌水平。结果提示：（1）iNKT 细胞可以增强OVA诱导的哮喘小鼠Th2反应，但并非必需；（2）iNKT 细胞通过增强OVA诱导的哮喘小鼠LDCs免疫原性成熟参与Th2反应；（3）iNKT 细胞增强哮喘小鼠LDCs免疫原性成熟可能与CD40L分子有关。. 实验按照项目资助计划书进行实施，目前已发表论文6篇，其中SCI源1篇，国内核心5篇，国内核心接收1篇，SCI源接收1篇、修稿1篇；国内学术会议交流3次；毕业硕士研究生3名，在读2名。