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: 6355588
• 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: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2001-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6355588
• 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.

有人建议进行研究，以确定免疫的机制 嗜酸性粒细胞的激活和黏附转化为增强 哮喘时出现的支气管运动音调。通过协作 由NHLBI肺病研究所和中国科学院研究部共同建立 德意志联邦共和国，已经开发了一种方法来评估影响 活化人嗜酸性粒细胞在移植人的显微切片上的表达 支气管路。这些研究利用了一种新开发的 视频显微测量技术与计算机在线集成 250微孔室中的气道腔直径。一个中环 这些研究的假设是与内皮和/或 细胞基质激发嗜酸性粒细胞释放炎症介质 会导致呼吸道平滑肌收缩加剧。在首字母中 将进行一系列实验，研究以评估其机理。 使嗜酸性粒细胞长时间暴露(大于或等于24小时) 对骨髓瘤蛋白IgE和/或白介素4的诱导上调 抗原交联物对刺激的天然分泌反应 使用一种新的抗IgE抗体(TN142)。这些研究考察了 假设免疫刺激本身是一种初始启动事件 内皮移行过程中嗜酸性粒细胞的激活。在一个 第二系列研究，炎性细胞的增强作用 免疫-AND引起的支气管收缩与内皮结合 将对药物激活的嗜酸性粒细胞进行检查。初步 研究表明，结扎人脐带静脉内皮细胞 细胞(HUVEC)引起嗜酸性粒细胞分泌上调并增强 人的支气管外植体变窄。进一步的研究将审查 导致这种扩大狭窄的特定配体和一种机制 有选择地封锁这一反应。在第三系列研究中， 嗜酸性粒细胞与基质蛋白、纤维连接蛋白、 通过表面配体VLA-4也将被检测。初步 调查表明，这是一个极其缓慢的绑定过程 这使得嗜酸性粒细胞的分泌活动持续增强。 建议进行研究，以直接检查这种长期的影响。 与免疫激活引起的收缩反应的结合 嗜酸性粒细胞在人支气管外植体上的表达及机制探讨 这是通过用单抗选择性阻断来增强收缩的 针对特定细胞表面配体的抗体，例如抗VLA-4(HP 2/1)。在……里面 每项研究，低亲和力CD23受体的作用， Fcepsilon RII，激活嗜酸性粒细胞分泌和随后的呼吸道 将检查收缩能力，以及 暴露于重组人白介素4和免疫球蛋白E可引起该受体上调 评估过了。类似的研究将使用药理学方法进行 外源性血小板活化因子的激活及其潜能 低氧对支气管收缩的直接免疫调节作用 将检测亲和力嗜酸性粒细胞IgE受体。所有必需品 已初步制定了拟议研究的方法学 对这项提议的研究。从这些研究中得出的数据应该 阐明一种不寻常的(嗜酸性)模式的发病机制 炎症使人的呼吸道出现高反应性，因为 发生在人类哮喘中。