MECHANISMS OF HUMAN BASOPHIL & MAST CELL DESENSITIZATION

嗜碱性粒细胞和肥大细胞介质释放是两者的中心特征 急性和慢性过敏反应。 然而，人们所知甚少。 这是人类细胞中信号转导的生物化学性质。 类型. 这项建议的重点是进行研究，以阐明 IgE介导的和单价激素的重要生化事件 诱导分泌。 这些研究的主要目的是阐明 脱敏的机制，虽然重大的努力，也将 应用于理解激活事件。 特别是 胞浆钙升高和蛋白激酶C在活化中的作用 和脱敏将进一步研究。 我们已经证明 IgE介导的人嗜碱性粒细胞和肺肥大细胞组胺释放 细胞伴随着膜相关活性的增加 蛋白激酶C和胞质钙升高。 详细研究 这表明脱敏过程是特定的调解人 和调节脱粒程度的方法 （组胺释放），嗜碱性粒细胞和肥大细胞调节激活 蛋白激酶C而不是胞浆钙离子的升高。 因此，本提案的一部分旨在更详细地了解 PKC激活与组胺释放的关系， PKC可能在调节介质释放中发挥多种作用， PKC活性的瞬时激活是由特异性 调节甘油二酯水平。 一系列的探索性实验 来确定酪氨酸激酶活性是否在 在脱敏方面。 初步证据还表明， 与组胺释放不同， 钙的反应。 拟议的研究将首先审查 钙反应的下调与 调节白三烯的释放。 第二个主要研究领域将 钙振荡之间的关系，观察到在单一的 细胞和随后的介质释放。 提出了几种方法， 测量单细胞脱粒，以试图将这一目的与 点与细胞质钙的早期振荡变化。 在 此外，钙振荡和白三烯之间的关系 释放将被审查。 本建议的第三个目的是研究 影响早期免疫系统的脱敏事件 介质（组胺和白三烯）和细胞因子分泌， 发生在分泌反应的后期。 由于细胞因子释放 似乎依赖于mRNA的积累，初步研究将集中在 mRNA积累的机制。

Basophil and mast cell mediator release is a central feature of both acute and chronic allergic reactions. However, little is known of the biochemical nature of signal transduction in the human cells of this type. This proposal focuses on studies which will elucidate some of the important biochemical events in both IgE mediated and univalent hormone induced secretion. The primary goals of these studies is to elucidate the mechanisms of desensitization although significant effort will also be applied towards understanding activation events. In particular, the role of cytosolic calcium elevations and protein kinase C in activation and desensitization will be further examined. We have demonstrated that IgE-mediated histamine release in both human basophils and lung mast cells is accompanied by the increased activity of membrane associated protein kinase C and elevations in cytosolic calcium. Detailed studies suggest that desensitization processes are specific for the mediator being examined and that for regulating the extent of degranulation (histamine release), the basophil and mast cell regulate the activation of protein kinase C rather than elevations in cytosolic calcium. Therefore, part of this proposal seeks to understand in greater detail the relationship between PKC activation and histamine release, the multiple roles PKC may play in regulating mediator release and whether the transient activation in PKC activity results from the specific regulation of diacylglycerol levels. A series of exploratory experiments are proposed to determine whether tyrosine kinase activity plays a role in desensitization. Preliminary evidence also suggests that leukotriene release, unlike histamine release, is controlled by the down-regulation of the calcium response. The proposed studies will initially examine the relationship between down-regulation of the calcium response and down- regulation of leukotriene release. A second primary area of study will be on the relationship between calcium oscillations observed in single cells and subsequent mediator release. Several methods are proposed to measure single cell degranulation in an effort to correlate this end point with the early oscillatory changes in cytosolic calcium. In addition, the relationship between calcium oscillations and leukotriene release will be examined. A third aim of this proposal is to study the relationship between desensitization events that affect the early mediators (histamine and leukotrienes) and cytokine secretion which occurs much later in the secretory response. Since cytokine release appears dependent on mRNA accumulation, initial studies will focus on the mechanisms of mRNA accumulation.