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: 6242694
• 负责人: ALAN Richard LEFF
• 金额: $ 27.07万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-01 至 1998-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6242694
• 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.

提议进行研究以确定免疫的机制 嗜酸性粒细胞的活化和粘附被转化为增强 人类哮喘中出现的支气管运动张力。 通过合作 由 NHLBI 肺脏研究所和研究部共同建立 德国已开发出一种方法来评估其影响 外植人类显微切片上活化的人类嗜酸性粒细胞 支气管气道。 这些研究利用了新开发的 视频显微测量技术和在线计算机化集成 250 微升微孔室中的气道管腔直径。 一个中央 这些研究的假设是与内皮细胞的粘附和/或 细胞基质启动嗜酸性粒细胞释放炎症介质 导致气道平滑肌收缩增强。 在最初的 一系列实验，将进行研究以评估其机制 长时间暴露于嗜酸性粒细胞（大于或等于 24 小时） 骨髓瘤蛋白 IgE 和/或白细胞介素 (IL)-4 导致上调 对抗原交联刺激的天然分泌反应 使用新型抗 IgE 抗体 (TN142)。 这些研究考察了 假设免疫刺激本身是初始启动事件 内皮细胞迁移过程中嗜酸性粒细胞的激活。 在一个 第二系列研究，炎症细胞的增强作用 与免疫和免疫引起的支气管收缩上的内皮细胞结合 将检查药物激活的嗜酸性粒细胞。 初步的 研究表明，结扎人脐带静脉内皮细胞 细胞（HUVEC）导致嗜酸性粒细胞分泌上调并增强 人类支气管外植体变窄。 进一步的研究将检验 负责这种增强狭窄的特定配体和机制 用于选择性封锁这种反应。 在第三个系列的研究中， 嗜酸性粒细胞与基质蛋白、纤连蛋白结合的影响， 通过表面配体VLA-4也将被检查。 初步的 调查表明这是一个极其缓慢的结合过程 这使得嗜酸性粒细胞分泌活性持续增强。 建议进行研究以直接检验这种长期影响的影响 结合免疫激活引起的收缩反应 人支气管外植体上的嗜酸性粒细胞并确定其机制 这种通过单克隆抗体选择性阻断来增强收缩 针对特定细胞表面配体的抗体，例如抗 VLA-4 (HP 2/1)。在 每项研究，低亲和力 CD23 受体的作用， FcepsilonRII，激活嗜酸性粒细胞分泌和随后的气道 将检查收缩性，以及之间的关系 由于暴露于 rhIL-4 和 IgE 而导致该受体的上调 评估。 将使用药理学方法进行类似研究 外源性血小板活化因子的活化，以及潜在的 通过低浓度直接免疫调节支气管收缩的作用 将检查嗜酸性粒细胞 IgE 受体的亲和力。 全部必备 初步制定了拟议研究的方法 对此提案进行研究。 从这些研究中得出的数据应该 阐明异常（嗜酸性）模式的机制 炎症使人类支气管气道产生高反应性 发生在人类哮喘中。