Isocyanate Antigens and T-cells that Cause Asthma

二异氰酸酯是一组高活性、广泛使用的低分子化学品，是发达国家职业性哮喘最常见的报告原因。然而，二异氰酸酯导致哮喘和处于危险之中的人的机制。理论上认为，反应性二异氰酸酯是一种低分子量半抗原，可以触发人类T细胞反应。然而，对于体内二异氰酸酯的天然“载体”蛋白，以及暴露后引发哮喘相关呼吸道炎症的假定T细胞，仍存在相当大的不确定性。我们假设二异氰酸酯与人类呼吸道中的特定蛋白质结合，包括白蛋白和角蛋白-18，并且这些二异氰酸酯哮喘患者和接触非哮喘工人对二异氰酸酯偶联蛋白抗原表现出不同的T细胞反应，这将有助于理解二异氰酸酯哮喘的发病机制和识别这些受试者。为了验证这些假设，我们将：(目标1)进一步表征暴露于正常人体呼吸道组织和蛋白质后产生的生物相关二异氰酸酯-蛋白质复合体，(目标2)。根据二异氰酸酯-蛋白质结合物的体外反应评估T细胞的二异氰酸酯抗原性，并通过对二异氰酸酯哮喘患者和暴露对照组的呼吸道活检和外周血中T细胞的体外研究，确定不同T细胞亚群(即CD4+、CD8+、α/β、伽马/β)在二异氰酸酯结合蛋白致病免疫反应中的作用。这些研究建立在我们之前的工作基础上，该工作确定了体内存在的新型二异氰酸酯-蛋白质结合物，并从人类呼吸道内支气管镜活检样本中产生了抗原特异性T细胞系。这些实验将利用耶鲁医学院正在进行的研究中定义明确的二异氰酸酯哮喘患者和对照受试者的外周血液、支气管灌洗和呼吸道活检样本。总而言之，这些结果应该为二异氰酸酯哮喘的发病机制提供重要的见解。

Diisocyanates are a group of highly reactive, widely used low molecular weight chemicals, and are the most commonly reported cause of occupational asthma in developed countries. Yet, the mechanisms by which diisocyanate-induced asthma and those at risk. It has been theorized that reactive diisocyanates act as low-molecular weight haptens that trigger human T-cell responses. However, considerable uncertainty exists regarding the natural "carrier" proteins for diisocyanate in vivo and the putative T-cells central to eliciting asthma- related airway inflammation following exposure. We hypothesize that diisocyanates bind to specific proteins in human airways including, albumin and keratin-18, and that these diisocyanate asthmatics and exposed non-asthmatic workers manifest distinct T-cell responses to diisocyanate-conjugated protein antigens that will aid in understanding the pathogenesis of diisocyanate asthma and identifying these subjects. To test these hypotheses we will: (AIM 1) Further characterize biologically relevant diisocyanate-protein complexes that result following the exposure of normal human airway tissues and proteins, (AIM 2). Evaluate diisocyanate antigenicity at the T-cell based on in vitro responses t specific diisocyanate-protein conjugates, and (AIM 3) Determine the roles of different T cell subsets (i.e. CD4+, CD8+, alpha/beta, gamma/beta) in the pathogenetic immune response to diisocyanate-conjugated proteins, through in vitro studies with T cells derived from airway biopsies and peripheral blood of diisocyanate asthmatic and exposed control subjects. These studies build upon our previous work that has identified novel diisocyanate-protein conjugates that occur in vivo and has generated antigen-specific T-cell lines from human airway endobronchial biopsy samples. The experiments will utilize peripheral blood; bronchial lavage and airway biopsy samples from a well-defined population of diisocyanate asthmatic and control subjects enrolled in ongoing studies at the Yale School of Medicine. Together the results should provide significant insights into the pathogenesis of diisocyanate asthma.