Ambient TLR Ligand Exposures and the Genesis of Asthma

描述(由申请人提供)：在婴儿期和早期儿童时期，一部分具有允许基因的儿童会出现空气过敏和哮喘，而其他儿童则不会。流行病学和实验室研究表明，早期接触Toll样受体(TLR)配体可能对哮喘的发生有深远的影响。因此，我们建议确定在成年和2周大的小鼠中，呼吸道暴露于室内灰尘提取物(HDE)中纯化的TLR配体和TLR配体如何影响先天和获得性免疫以及随后对呼吸道变应原攻击的反应：表征生命早期的气道暴露于肽聚糖(PGN；TLR2)、脂多糖(TLR4)和免疫刺激序列OLR9(ISS-ODN；TLR9)如何影响先天和获得性免疫以及气道变应原耐受-TLR2、TLR4和TLR9配体已知普遍存在并诱导不同的免疫反应。因此，我们将比较PGN、LPS和ISS-ODN诱导的肺相关DC的成熟以及它们随后在免疫突触中与幼稚的CD4细胞的功能。体外和体内模型将用于成年和2周大小鼠的比较分析。在其他实验中，小鼠将被免疫接种。单独使用OVA或与PGN、LPS或ISS-ODN免疫，将分析免疫和呼吸道变应原攻击反应。SA-2：研究早期呼吸道暴露于屋尘提取物(HDE)中包含的TLR配体如何影响先天和获得性免疫以及呼吸道变应原耐受性--对纯化的PGN、LPS和ISS-ODN的研究将有助于确定它们在肺部的独特免疫活性。然而，在现实世界中，潜在的哮喘婴儿和蹒跚学步的儿童可能会同时接触各种TLR配体和潜在的其他免疫刺激元素。因此，为了补充纯化的TLR配体的研究，我们将首先检测来自耐受家庭(牲畜、狗和猫等)的t-HDE的内毒素和革兰氏阳性细菌DNA含量和阴性细菌DNA含量。以及允许Th2偏向呼吸道过敏原过敏的家庭(没有接触动物的家庭)。然后，在与SA-1中建议的研究类似的研究中，我们将确定来自耐受家庭和哮喘允许家庭的HDE如何影响成年和2周大小鼠的气道DC成熟、CD4细胞分化和宿主对空气过敏原过敏的敏感性。

DESCRIPTION (provided by applicant): During infancy and early childhood a subset of children with permissive genotypes develop aeroallergen hypersensitivities and asthma, while others do not. Epidemiological and laboratory investigations suggest that early life exposures to toll like receptor (TLR) ligands may have a profound impact on the genesis of asthma. Therefore, we propose to determine how airway exposures to purified TLR ligands and TLR ligands within house dust extracts (HDEs) impact on innate and adaptive immunity and subsequent responses to airway allergen challenge, in adult and 2-week old mice SA-I: Characterize how early life airway exposures to peptidoglycan (PGN; TLR2), LPS (TLR4) and immunostimulatory sequence oIigodeoxynucleotide (ISS-ODN; TLR9) influence innate and adaptive immunity and airway allergen tolerance- TLR2, TLR4, and TLR9 ligands are known to be ubiquitous and to induce divergent immunological responses. Therefore, we will compare PGN, LPS, and ISS-ODN induced maturation of lung associated DCs and their subsequent functionality in the immunological synapse with naive CD4 cells. In vitro and in vivo models will be utilized in comparative analyses of adult and 2-week old mice. In additional experiments, mice will be i.n. immunized with OVA alone or with PGN, LPS, or ISS-ODN, and immune and airway allergen challenge responses will be analyzed. SA-2: Characterize how early life airway exposures to TLR ligands contained in house dust extracts (HDEs) influence innate and adaptive immunity and airway allergen tolerance- Studies with purified PGN, LPS, and ISS-ODN will help define their unique immunological activities in the lungs. However, in the real world, potential asthmatic infants and toddlers are likely to have simultaneous exposures to a variety of TLR ligands and potentially other immunostimulatory elements, as well. Therefore, to complement studies with purified TLR ligands, we will first measure the LPS and Gram positive and negative bacterial DNA content of t-HDEs from homes that are tolerance (homes with livestock, dogs and cats etc.) and homes permissive for Th2 biased airway allergen hypersensitivities (homes without animal exposures). Then in studies analogous to those proposed in SA-1, we will determine how HDEs from tolerogenic and asthma permissive homes influence airway DC maturation, CD4 cell differentiation, and host susceptibility towards aeroallergen hypersensitivities in adult and 2 week old mice.