MECHANISMS AND CONSEQUENCES OF EOSINOPHIL ACTIVATION WITHIN AIRWAYS

气道内嗜酸性粒细胞激活的机制和后果

• 批准号: 6110700
• 负责人: ALAN Richard LEFF
• 金额: $ 28.77万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-01 至 1999-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6110700
• 关键词: antibody receptor; asthma; bronchomotion; cell adhesion; eosinophil; fibronectins; human subject; immunoglobulin E; inflammation; interleukin 4; leukocyte activation /transformation; muscle contraction; respiratory hypersensitivity; smooth muscle; video microscopy

Studies are proposed to determine the mechanisms by which immune activation and adhesion of eosinophils are translated into augmented bronchomotor tone as occurs in human asthma. Through a collaboration established by the Lung Institute of NHLBI and the Research ministry of the Republic of Germany, a method has been developed to assess the effects of activated human eosinophils on microsections of explanted human bronchial airways. These studies utilize using a newly developed technique for videomicrometry and on-line computerized integration of airway lumenal diameter in 250 microl microwell chambers. A central hypothesis of these investigations is that adhesion to endothelium and/or cellular matrix primes eosinophils for release of inflammatory mediators that cause augmented airway smooth muscle contraction. In an initial series of experiments, studies will be performed to assess the mechanism by which prolonged exposure of eosinophils (greater than or equal to 24 h) to myeloma protein IgE and/or interleukin (IL)-4 causes upregulation of the native secretory response to stimulation by antigenic cross linking using a novel anti-IgE antibody (TN142). These studies examine the hypothesis that immune stimulation per se is an initial priming event in the activation of eosinophils during endothelial transmigration. In a second series of studies, the augmenting effect of inflammatory cell binding to endothelium on the bronchoconstriction caused by immune- and pharmacologically activated eosinophils will be examined. Preliminary studies indicate that ligation to human umbilical cord vein endothelial cells (HUVEC) causes upregulated secretion of eosinophils and augmented narrowing of human bronchial explants. Further studies will examine the specific ligands responsible for this augmented narrowing and a mechanism for selective blockade of this response. In a third series of studies, the effect of eosinophil binding to the matrix protein, fibronectin, through the surface ligand VLA-4 also will be examined. Preliminary investigations indicate that this is an extremely slow binding process that confers sustained augmentation of eosinophil secretory activity. Studies are proposed to examine directly the effects of this prolonged binding on the contractile response elicited by immunologically activated eosinophils on human bronchial explants and to determine the mechanism of this augmented contraction through selective blockage with monoclonal antibodies to specific cell surface ligands, e.g., anti-VLA-4 (HP 2/1). In each investigation, the role of the low affinity CD23 receptor, FcepsilonRII, in activating eosinophil secretion and consequent airway contractility will be examined, and the relationship between the upregulation of this receptor caused by exposure to rhIL-4 and IgE will be assessed. Comparable studies will be done using pharmacological activation with exogenous platelet activating factor, and the potential role for direct immune regulation of bronchial contraction through the low affinity eosinophil IgE receptor will be examined. All essential methodologies for proposed studies have been developed in preliminary studies for this proposal. Data derived from these studies should elucidate mechanisms by which an unusual (eosinophilic) mode of inflammation confers hyperresponsiveness upon human bronchial airways as occurs in human asthma.

提出了研究以确定免疫的机制 嗜酸性粒细胞的激活和粘附被翻译成增强 人类哮喘中的支气管运动张力。 通过合作 由NHLBI肺部和研究部成立 德国共和国，已经开发了一种方法来评估影响 激活的人类嗜酸性粒细胞在植物的微切片上 支气管气道。 这些研究使用新开发 视频计量学和在线计算机化的技术的技术集成 250 Microl Microwell腔室中的气道腔直径。 中央 这些调查的假设是对内皮和/或的粘附 细胞基质素嗜酸性粒细胞用于释放炎症介质 这会导致气道平滑肌收缩。 最初 一系列实验，将进行研究以评估机制 通过该嗜酸性粒细胞的长时间暴露（大于或等于24小时） 到骨髓瘤蛋白IgE和/或白介素（IL）-4引起上调 抗原交叉连接对刺激的本地分泌反应 使用新型抗IgE抗体（TN142）。 这些研究检查了 假设免疫刺激本身是初始启动事件 内皮转移过程中嗜酸性粒细胞的激活。 在 第二系列研究，炎症细胞的增强作用 与免疫和免疫造成的支气管收缩结合 将检查药理学活化的嗜酸性粒细胞。 初步的 研究表明与人脐带静脉结扎 细胞（HUVEC）引起嗜酸性粒细胞的分泌上调并增强 人类支气管外植体的变窄。 进一步的研究将研究 特定的配体负责这种增强的狭窄和机制 为了选择性封锁此响应。 在第三个研究中， 嗜酸性粒细胞与基质蛋白（纤连蛋白）结合的作用， 还将检查通过表面配体VLA-4。 初步的 调查表明这是一个极慢的绑定过程 这赋予了嗜酸性分泌活性的持续增强。 提出了研究以直接检查该延长的影响 通过免疫学激活引起的收缩反应结合 嗜酸性粒细胞在人支气管外植体上，并确定 通过单克隆的选择性阻塞这种增强收缩 特定细胞表面配体的抗体，例如抗VLA-4（HP 2/1）。在 每个研究，低亲和力CD23受体的作用， fcepsilonrii，激活嗜酸性粒细胞分泌和随之而来的气道 将检查收缩力，以及 暴露于Rhil-4和IgE引起的该受体的上调将是 评估。 可比较的研究将使用药理学 用外源血小板激活因子激活，电势 直接免疫调节支气管收缩的作用 将检查亲和力嗜酸性粒细胞IgE受体。 都是必不可少的 提出的研究方法已在初步中开发 该提议的研究。 这些研究得出的数据应 阐明机制，通过这种机制，这种机制是一种异常（嗜酸性）模式的机制 炎症赋予人支气管气道的过度反应性 发生在人类哮喘中。