TRANSMEMBRANE SIGNALING IN THE ACTIVATION OF NK CELLS

自然杀伤(NK)细胞是一种大颗粒淋巴细胞，自发地 溶解某些肿瘤细胞和细胞系。我们之前已经证明了NK 细胞通过刺激靶细胞对靶细胞作出特异性反应 多聚磷脂酰肌醇(PPI)信号通路，导致 肌醇磷酸盐和细胞内钙的上升，我们发现 这些信号与细胞毒性有关。通过研究一只类NK大鼠 白血病细胞系RNK-16，我们已经鉴定出两个以前未知的 可以刺激PPI途径的表面分子。我们建议的研究 将详细研究其中之一的GP42的功能和调节。 GP42通过锚定在RNK-16细胞上表达 糖基磷脂酰肌醇(GPI)：它是唯一已知的GPI锚定的 淋巴细胞上的分子，在没有T细胞的情况下可以发出信号 受体。我们建议的研究的第一个目标是界定 GP42信令的结构要求。我们的第二个方面 研究涉及限制大鼠白细胞上GP42的表达。GP42 它不是由静止的NK细胞表达的，但它是在NK细胞上唯一诱导的 细胞对白介素2(IL-2)的反应。这是唯一的激活 NK细胞所特有的抗原。我们提议的工作的第二个目标是 就是定义限制基因表达的基因调控元件 GP42激活的NK细胞。我们提案的第三个目标是克隆 人GP42基因的克隆及其在制备抗人GP42单抗中的应用 对人类GP42的研究。

Natural killer (NK) cells are large granular lymphocytes that spontaneously lyse certain tumor cells and cell lines. We have previously shown that NK cells respond specifically to target cells by stimulating the polyphosphoinositide (PPI) signaling pathway, leading to the generation of inositol phosphates and a rise in intracellular calcium, and we showed that these signals are associated with cytotoxicity. By studying an NK-like rat leukemia cell line, RNK- 16, we have identified two previously unknown surface molecules that can stimulate the PPI pathway. Our proposed studies will examine in detail the function and regulation of one of these, gp42. gp42 is expressed on RNK-16 cells by anchoring to glycosylphosphatidylinositol (GPI): it is the only known GPI-anchored molecule on lymphocytes that can signal in the absence of the T cell receptor. The first goal of our proposed studies is to define the structural requirements for signaling by gp42. A second aspect of our studies involves the restricted expression of gp42 on rat leukocytes. gp42 is not expressed by resting NK cells, but it is uniquely induced on NK cells in response to interleukin-2 (IL-2). It is the only activation antigen that is specific for NK cells. The second goal of our proposed work is to define the genetic regulatory elements that restrict expression of gp42 to activated NK cells. The third goal of our proposal is to clone the cDNA for human gp42 and to use this in developing monoclonal antibodies for the study of human gp42.