TARGET CELL LYSIS BY CYTOLYTIC EFFECTOR CELLS

细胞毒性T细胞（CTL）是免疫系统的基石之一。 系统 因此，人们很有兴趣了解 他们裂解目标的机制，这是总的目标， 这个提议。 尽管我们在这方面取得了重大进展， 对CTL裂解的理解仍有许多问题有待解决。 吸附 CTL通过受体作用于靶细胞， CTL中的细胞骨架元件。 这导致了 高尔基体（GA）朝向目标结合位点， 分泌通道形成蛋白-穿孔素（PF）-这是 被认为会导致靶细胞溶解。 最近的证据表明， 用体外CTL克隆建立的这一系列事件确实 不能在体内诱导CTL。 证据也在不断积累 通过通道形成的靶溶解可能不是通用的， CTL裂解的机制，并且靶点本身起着活性作用。 在其溶解作用。 我们建议探讨几个方面的 在体内诱导的CTL中CTL裂解的并行模型，因为 它们在体外尚未获得异常性质。 CTL将 高度纯化并测试它们是否显示GA重定向 因为这种反应被认为是 正确的目标识别 下一个CTL将被测试， 将PF通道插入红细胞膜的能力。 到 诱导该反应，我们将使用双功能抗靶抗T 细胞受体抗体缀合物。 如果CTL无法插入通道 我们将测试是否从红细胞中去除细胞核， 靶抑制靶裂解。 在药物抑制研究中， 一方面检查CTL的持续裂解活性， 靶对另一种所需蛋白质的裂解敏感性 在CTL-靶标结合之前进行合成。 初步数据支持 靶点参与CTL诱导的裂解的观点。 探讨 靶如何参与裂解，我们提出了几种方法， 其中之一是基于蛋白质合成抑制剂 干扰CTL裂解。 另一种是基于伴随的 对CTL裂解的抗性和对 糖皮质激素在一个细胞系中。 我们建议研究 糖皮质激素抵抗与 CTL的敏感性。 这将为一个共同的 两种细胞裂解机制的途径。 我们亦建议 选择CTL抗性靶标，以探索它们是否获得 对PF和/或糖皮质激素的抗性。 这些变体将 为研究假设的自杀途径提供了工具。 最后， 我们将探讨体内诱导的CTL是否改变了它们的免疫模式， 体外长时间培养细胞溶解并激活细胞通路 介导的裂解，已经描述了克隆的CTL。

Cytotoxic T cells (CTL) are one of the cornerstones of the immune system. There is therefore much interest in understanding the mechanism by which they lyse targets, which is the overall goal of this proposal. Although significant strides have been made in our understanding of CTL lysis many questions remain open. Adsorption of CTL to targets via receptors triggers polarization of cytoskeletal elements in the CTL. This leads to reorientation of the Golgi apparatus (GA) towards the target binding site and secretion of channel forming proteins -perforins (PF) - which are thought to cause target cell lysis. Recent evidence suggest s that this sequence of events established with in vitro CTL clones does not operate in vivo induced CTL. Evidence is also accumulating that target lysis by channel formation may not be the universal mechanism of CTL lysis and that the target itself plays an active role in its lysis. We propose to explore several aspects of the concurrent models for CTL lysis in in vivo induced CTL, because they have not yet acquired abnormal properties in vitro. CTL will be highly purified and tested whether they show GA reorientation when bound to targets because this reaction is thought to signal proper target recognition. Next CTL will be tested as to their ability to insert PF channels into erythrocyte membranes. To induce this reaction we will use bifunctional anti-target anti-T cell receptor antibody conjugates. If CTL fail to insert channels into erythrocytes we will test whether removal of nuclei from targets inhibits target lysis. In drug inhibition studies we will examine whether continued lytic activity of the CTL on one hand and lytic susceptibility of the target on the other require protein synthesis prior to CTL-target binding. Preliminary data support the view that targets participate in CTL induced lysis. To explore how targets participate in lysis we propose several approaches, one of which is based on the ability of protein synthesis inhibitors to interfere with CTL lysis. Another is based on the concomitant occurrence of resistance to CTL lysis and resistance to glucocorticoids in one cell line. We propose to examine whether there indeed exists a correlation between glucocorticoid resistance and CTL sensitivity. This would provide support for a common pathway for both mechanisms of cell lysis. We also propose to select CTL resistant targets to explore whether they acquire resistance to PF and/or glucocorticoids. These variants will provide the tool to study the postulated suicide pathway. Finally, we will explore whether in vivo induced CTL change their mode of lysis upon prolonged culture in vitro and activate pathways of cell mediated lysis that have been described for cloned CTL.