MOLECULAR PATHWAYS INVOLVED IN THE PROGRAMMED DEATH OF LYMPHOCYTES

很明显，体内的死亡程序控制着体内免疫细胞的数量和类型。疾病可由淋巴细胞无效率死亡或不适当或过度死亡引起，例如艾滋病期间由人类免疫缺陷病毒（HIV）引起的死亡。在这个项目中，我们正在采取多方面的方法来研究淋巴细胞中这种死亡程序的分子机制。我们研究的一个主要焦点是一种叫做CD95/Fas/APO-1的细胞表面受体，它在刺激免疫细胞死亡中起重要作用。我们正试图了解这种受体是如何刺激细胞内机制导致细胞死亡的。我们特别关注了一种被称为Flice/Mach1 （caspase 8）的蛋白酶的激活，它可以直接执行死亡程序。这些研究将帮助我们确定细胞如何启动自身死亡，其调控可能在各种疾病中发挥作用，从自身免疫性疾病到艾滋病等传染病。在感染艾滋病毒后，艾滋病发病的一个关键影响被认为是由病毒引起的T淋巴细胞死亡。我们已经发现这种死亡过程不同于细胞凋亡，并且在鉴定参与这一过程的病毒基因产物方面正在取得进展。然后，我们将从生化角度解释病毒产物是如何触发T细胞死亡的。

It has become clear that an internal death program controls the number and types of immune cells in the body. Diseases can result from inefficient lymphocyte death or from inappropriate or excessive death such as is caused by the human immunodeficiency virus (HIV) during AIDS. In this project we are taking a multifaceted approach to studying molecular mechanisms of this death program in lymphocytes. A major focus of our investigations is a cell surface receptor called CD95/Fas/APO-1 that plays an important role in stimulating the death of immune cells. We are trying to understand how this receptor stimulates the intracellular machinery that causes cellular demise. In particular we have focused on the activation of a protease termed Flice/Mach1 (caspase 8) which can directly carry out the death program. These studies will help us to determine how cells can initiate their own death whose regulation may play a role in various diseases ranging from autoimmune conditions to infectious diseases such as AIDS. Following infection with HIV, a critical effect in the onset of AIDS is believed to be death of T lymphocytes caused by the virus. We have found that this death process is distinct from apoptosis and are making progress in indentifying the viral gene product(s)that are involved in this process. We would then like to explain how the virus product triggers the death of T cells in biochemical terms.