婴儿期PCV7呼吸道免疫抑制实验性哮喘的作用及机制研究

Studies suggest inducing Foxp3+Treg development play important role in asthma. Our previous study indicated infant PCV7 respiratory immunization promote Foxp3+Treg development and inhibit experimental asthma. Recent studies demonstrated CD103+DC can induce Foxp3+Treg development through indoleamine 2,3-Dioxygenase(IDO).IDO production elevated when TLR2/4/9 is actived. It is unclear whether infant PCV7 respiratory immunization can promote CD103+DC-IDO and CD103+DC production through TLR2/4/9 to induce Foxp3+Treg development. We aim to study the role of TLR2/TLR4/TLR9 in infant PCV7 respiratory immunization on the the production of CD103+DC-IDO and CD103+DC during experimental asthma , to investigate the effect of CD103+DC on airway inflammation, airway hyperresponsiveness and Foxp3+Treg development in infant PCV7 immunization mice, to determine PCV7 impact on CD103+DC inducing Foxp3+Treg development and their association with CD103+DC-IDO productions. Through the research we can determine the immune mechanisms of infant PCV7 respiratory immunization inducing Foxp3+Treg development and provide new theoretical foundation for primary prevention and clinical treatment of asthma.

促进Foxp3+Treg发育在哮喘防治中有重要作用。我们发现婴儿期PCV7呼吸道免疫促进肺部Foxp3+Treg发育抑制哮喘发生，CD103+DC通过IDO诱导Foxp3+Treg发育，TLR2/4/9激活能促进DC产生IDO，PCV7免疫是否通过TLR2/4/9促进CD103+DC-IDO表达诱导Foxp3+Treg发育抑制哮喘发生未见报道。本课题拟研究TLR2/4/9在PCV7呼吸道免疫对哮喘小鼠CD103+DC-IDO表达水平的影响；研究CD103+DC在婴儿期PCV7呼吸道免疫对哮喘气道炎症、气道高反应性及Foxp3+Treg分化发育的影响；探讨PCV7对CD103+DC诱导Foxp3+Treg发育的影响；探讨IDO对PCV7促进CD103+DC诱导Foxp3+Treg分化发育的影响，阐明PCV7呼吸道免疫诱导Foxp3+Treg发育抑制哮喘发生的机制，为哮喘一级预防提供新思路。

项目背景及意义：支气管哮喘(哮喘，asthma)是常见慢性气道炎症性疾病，其发病率呈持续上升趋势。哮喘在儿童时期最常见，其中50%在3岁前发病，80%在5岁前发病，我国儿童哮喘现患率、累计患病率10年间分别增加了50.6％、52.8％，因此，寻找早期防治哮喘的有效方法具有重要意义。.研究内容、成果及重要数据：.1.已完成实验性哮喘模型，分析了对照组（Control 组）、PCV7免疫实验性哮喘组（PCV7+OVA组）、实验性哮喘组（OVA组）气道炎症和气道高反应性。.2.课题组研究发现婴儿期BALB/c 小鼠鼻腔滴注PCV7 后，PCV7+OVA 组肺组织CD103+DC 显著高于OVA 组。.3.课题组已完成PCV7 对 DCs 细胞表型影响的研究体外培养，发现与OVA 比较，PCV7 显著降低CD40，CD86 及MHC-Ⅱ分子表达水平。.4.课题组已完成PCV7 对 DCs 培养上清细胞因子影响的研究。 .5.PCV7-CD103+DC、CD103+DC、OVA-CD103+DC 与初始CD4+T 共培养后，发现了PCV7-CD103+DC 诱导Foxp3+Treg 分化能力显著增强。.6.研究了PCV7-CD103+DC、CD103+DC、OVA-CD103+DC 与初始CD4+T 细胞共培养上清液TGF-β、IL-12、IL-4、IL-6 水平，明确PCV7-CD103+DC 对初始CD4+T 细胞分化方向前细胞因子的影响。.7. 研究证实了皮下植入1-MT缓释片能阻断肺部IDO表达。.8.课题组提取骨髓单个核细胞体外培养，加入FLT3L刺激CD103+DC细胞分化，磁珠分选CD103+DC细胞及初始CD4+T细胞共培养，期间实验性哮喘组加入OVA（1ug/ml），CD103+DC细胞与初始CD4+T细胞共培养发现，实验性哮喘组（OVA）组Foxp3+Treg显著低于对照组（Control）。.9.课题组通过磁珠分选CD103+DC细胞，完成了CD103+DC细胞尾静脉回输，建立了实验性哮喘回输CD103+DC组（OVA+CD103+DC）。.10.分析control组、OVA组及OVA+DC103+DC组气道炎症及气道高反应，发现回输CD103+DC细胞后，OVA+CD103+DC组气道炎症、气道高反应较OVA组显著减轻。