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: 6202512
• 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: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2000-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6202512
• 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.

建议进行研究以确定免疫的机制 嗜酸性粒细胞的激活和粘附被转化为增强 支气管紧张，如人类哮喘中发生的。 通过协同 由NHLBI的肺部研究所和研究部建立， 在德国共和国，已经制定了一种方法来评估影响， 活化的人嗜酸性粒细胞的显微切片 支气管 这些研究利用新开发的 视频显微测量和在线计算机集成技术 250微升微孔室中的气道管腔直径。 中央 这些研究的假设是粘附于内皮和/或 细胞基质引发嗜酸性粒细胞释放炎症介质 导致气道平滑肌收缩增强。 在初始 一系列的实验，研究将进行评估的机制 嗜酸性粒细胞的长期暴露（大于或等于24小时） 与骨髓瘤蛋白IgE和/或白细胞介素（IL）-4的结合导致 通过抗原交联对刺激的天然分泌反应 使用新的抗IgE抗体（TN142）。 这些研究考察了 假设免疫刺激本身是一个初始启动事件， 内皮细胞迁移过程中嗜酸性粒细胞的活化。 中 第二个系列的研究，炎症细胞的增强作用， 与内皮细胞结合引起支气管收缩， 将检查活化的嗜酸性粒细胞。 初步 研究表明，结扎人脐带静脉内皮 细胞（HUVEC）引起嗜酸性粒细胞分泌上调， 人支气管移植物变窄。 进一步的研究将审查 负责这种增强的狭窄和机制的特定配体 选择性地阻断这种反应。 在第三个系列的研究中， 嗜酸性粒细胞与基质蛋白，纤连蛋白， 通过表面配体VLA-4也将被检查。 初步 研究表明，这是一个非常缓慢的结合过程， 这赋予嗜酸性粒细胞分泌活性的持续增强。 研究建议直接检查这种长期的影响， 结合由免疫激活引起的收缩反应 嗜酸性粒细胞的人支气管外植体，并确定机制， 通过选择性阻断单克隆抗体， 特异性细胞表面配体的抗体，例如，抗-VLA-4（HP 2/1）。在 每次研究，低亲和力CD23受体的作用， FcepsilonRII，在激活嗜酸性粒细胞分泌和随后的气道 收缩性将被检查，和之间的关系 由暴露于rhIL-4和IgE引起的该受体的上调将是 评估。 将使用药理学方法进行可比性研究 用外源性血小板活化因子活化， 支气管收缩的直接免疫调节作用 将检查嗜酸性粒细胞IgE受体的亲和力。 所有基本 已初步制定了拟议研究的方法， 研究这个建议。 从这些研究中获得的数据应 阐明一种不寻常的（嗜酸性）模式的机制， 炎症赋予人支气管气道高反应性， 发生在人类哮喘中。