Il-2 Receptors--structure And Function

人IL-2受体和相关的细胞因子受体系统正在研究中，以澄清正常，肿瘤和免疫缺陷状态下的T细胞免疫应答。在T细胞被抗原激活后，T细胞免疫应答的幅度和持续时间由产生的IL-2的量、表达的受体水平和每个事件的时间过程决定。IL-2受体含有三条链，IL-2 Ra、IL-2 Rb和gc。伦纳德博士于1984年克隆了IL-2 Ra，他的小组于1986年发现了IL-2 Rb，并于1993年报道了GC链突变导致X连锁严重联合免疫缺陷在1995年，GC相关激酶Jak 3的突变导致与XSCID无法区分的常染色体隐性形式的SCID;在1998年，T-B+NK+ SCID是由IL 7 R基因突变引起的。基于本实验室和其他实验室的工作，已证明IL-2、IL-4、IL-7、IL-9、IL-15和IL-21的受体共享gc。鉴定IL-2和相关细胞因子诱导或抑制的基因的工作仍在继续，其中一些正在进行表征。一项关于IL-2介导的IL-7受体α链表达抑制的研究被接受，这一发现对理解IL-2如何促进细胞死亡以及抑制具有潜在的重要意义。IL-7介导的抑制机制依赖于PI 3-激酶和Akt。正在研究IL-2信号传导的其他方面，特别是IL-2诱导的丝氨酸磷酸化，并且鉴定了Stat 5a的主要丝氨酸磷酸化位点，并接受了手稿以供出版。有趣的是，这种磷酸化并没有像其他STAT蛋白那样产生积极的影响;相反，如果有的话，这种影响可能是负面的。在前一年报道了一种新的I型细胞因子受体蛋白的cDNA克隆，该蛋白被证明是胸腺基质淋巴细胞生成素（TSLP）的受体，该小组已经致力于创建TSLPR KO小鼠。另一种新的细胞因子受体的克隆，现在被称为IL-21受体，以前发表过，创造了一个新的领域。先前显示IL-21受体限于淋巴样细胞，在T细胞、NK细胞和B细胞上表达，并且该受体利用Jak-STAT途径。在过去的一年中，在研究这种蛋白在体内的作用方面取得了重大进展，证明它在免疫球蛋白的生物合成中起着关键作用。其在体内的功能正在进一步研究中。总的来说，这些研究有助于IL-2和相关细胞因子的信号转导方面。这些发现与免疫缺陷和T细胞生长的控制有关。

The human IL-2 receptor and related cytokine receptor systems are being studied to clarify the T cell immune response in normal, neoplastic, and immunodeficient states. Following T-cell activation by antigen, the magnitude and duration of the T-cell immune response is determined by the amount of IL-2 produced, levels of receptors expressed, and time course of each event. The IL-2 receptor contains three chains, IL-2Ra, IL-2Rb, and gc. Dr. Leonard cloned IL-2Ra in 1984, his group discovered IL-2Rb in 1986, and reported in 1993 that mutation of the gc chain results in X-linked severe combined immunodeficiency (XSCID, which has a T-B+NK- phenotype) in humans; in 1995 that mutations of the gc-associated kinase, Jak3, result in an autosomal recessive form of SCID indistinguishable from XSCID; and in 1998 that T-B+NK+ SCID results from mutations in the IL7R gene. Based on work in this lab and others, gc was shown to be shared by the receptors for IL-2, IL-4, IL-7, IL-9, IL-15, and IL-21. Work on the identification of genes induced or repressed by IL-2 and related cytokines has continued and some of these are being characterized. A study on IL-2-mediated repression of IL-7 receptor alpha chain expression was accepted, a finding with potential major implications in understanding how IL-2 can promote cell death as well as repression. The mechanism of IL-7-mediated repression depends on PI 3-kinase and Akt. Other aspects of IL-2 signaling, particularly IL-2-induced serine phosphorylation are being studied, and a major serine phosphorylation site of Stat5a was identified and a manuscript was accepted for publication. Interesting, this phosphorylation did not exert a positive effect as has been found for other STAT proteins; instead, if anything, the effect could be negative. Having reported the previous year the cDNA cloning of a novel type I cytokine receptor protein which was demonstrated to be the receptor for thymic stromal lymphopoietin (TSLP), the group has worked to create a TSLPR KO mouse. The cloning of another novel cytokine receptor, now denoted as the IL-21 receptor, was previously published, creating a new field. It was previously shown that the IL-21 receptor was restricted to lymphoid cells, with expression on T-cells, NK-cells, and B-cells and that the receptor utilized the Jak-STAT pathway. In the past year, major advances were made in studying the effect of this protein in vivo, demonstrating that it plays a criical role in immunoglobulin biosynthesis. Its function in vivo is being further studied. Overall, these studies help to aspects of signaling by IL-2 and related cytokines. These findings have relevance to immunodeficiency and the control of T-cell growth.