MECHANISMS OF HUMAN LUNG HYPERSENSITIVITY REACTIONS

该项目的长期目标是更好地了解 人肺过敏性疾病和哮喘的机制和控制。 本项目将重点研究肺高敏感性的中枢细胞， 人肺肥大细胞（HLMC）。 HLMC凭借其解剖结构 局部化，在刺激时产生有效的化学介质， 这些介质对细胞和组织靶点的作用可产生 这些疾病的病理生理表现：气道 收缩水肿和分泌过多。 这些研究涉及将人肺酶分散成单个细胞 悬浮液，通过淘洗将肺细胞（和HLMC）分离成 形态和功能上不同的亚群， 直径，并进一步分离这些馏分的基础上密度， 分级浮选 密度阶跃还导致 HLMC的纯化。 将对一个分离的HLMC亚群进行以下检查： 超微结构、介质含量和释放介质的能力。 将探讨对相关触发刺激的选择性反应。 这些刺激包括缺氧、过敏毒素、细菌碎片（f-met 肽），和一种新描述的介质，肺泡巨噬细胞（AM）- 衍生释放因子 此外，亚群的选择性反应 对上述刺激物释放的药理学抑制将是 考察 待测试的药剂包括B-肾上腺素能激动剂，PGE， 膜胆固醇结合剂和胆固醇合成抑制剂。 膜胆固醇在释放中的关键作用将被探讨 通过定量测量肥大细胞中胆固醇的合成， 激活-分泌 HLMC释放抑制的新机制 将研究膜脂质微环境的操纵。

The long term objective of this project is a better understanding of the mechanisms and control of human lung hypersentivity disorders and asthma. This project will focus on the central cell of lung hypersentivity, the human lung mast cell (HLMC). The HLMC by virtue of its anatomic localization, elaboration of potent chemical mediators upon stimulation and the effects of these mediators on cellular and tissue targets can produce the pathophysiologic manifestations of these disorders: airway constriction, edema and hypersecretion. The studies involve enzymatically dispersing human lung to a single cell suspension, separating lung cells (and HLMC) by elutriation into morphologically and functionally distinct subpopulations based on their diameter, and further separating these fractions on the basis of density by flotation through step-gradients. The density-step also results in purification of HLMC. One isolated, HLMC subpopulations will be examined with respect to ultrastructure, mediator content and capacity to release mediators. Selective responsiveness to relevant triggering stimuli will be explored. These stimuli include hypoxia, anaphylatoxins, bacterial fragments (f-met peptide), and a newly described mediator, an alveolar macrophage (AM) - derived releasing factor. Also, selective responsiveness of subpopulations to pharmacologic inhibition of release to the above stimuli will be examined. The agents to be tested include B-adrenergic agonists, PGE, membrane cholesterol binders and cholesterol synthesis inhibitors. The crucial role of membrane cholesterol in release will be explored through quantitative measurements of cholesterol synthesis during mast cell activation-secretion. Novel mechanisms of HLMC release inhibition through manipulation of the membrane lipid micro-environment will be studied.