HUMAN B CELL TRANSFORMATION BY EPSTEIN BARR VIRUS

爱泼斯坦-巴尔病毒(EBV)是一种具有因果关系的人类病原体 良性和恶性B细胞淋巴组织增殖和 鼻咽癌。免疫功能受损的个人，如艾滋病 患者和移植受者感染EBV的风险很高- 相关的B细胞淋巴瘤。病毒诱导的生长变化 受感染B细胞的特性可能是EBV贡献的基础 这些淋巴增生性疾病。原发人类B-型感染 细胞在体外EBV导致激活静息B细胞从 从静止状态转变为增殖状态。这些被感染的细胞进入 细胞周期，并能够无限增殖，因此 永垂不朽。EBV的独特之处在于它能使初级休眠永垂不朽 B细胞体外培养。EB病毒感染的B细胞进入细胞周期和 维持细胞的增殖状态是绝对依赖的 病毒基因的表达。这项建议的总体目标是 分析EBV的一个特定基因产物(LMP-1)对 永垂不朽。LMP-1的研究对人类免疫缺陷的研究具有特别重要的意义。 原因如下：1)LMP-1是4种潜伏基因产物之一，也是唯一的 膜蛋白，被证明是EBV永生所必需的；ii) LMP-1对培养细胞的生长有深远的影响 在啮齿动物细胞中起癌基因的作用)；iii)LMP-1位于 与之相关的质膜，通过其细胞质氨基- 终点处，带有细胞骨架。LMP-1必须与细胞信号相互作用 调节正常B细胞增殖的信号转导通路 确定涉及到的信号通路的理想起点 通过EB病毒永垂不朽。这项工作的具体目标是使用 LMP-1的生化和遗传分析：I)确定 LMP-1的跨膜拓扑结构；II)研究LMP-1的四级结构 LMP-1及其与功能的相关性；以及iii)确定关系 在LMP-1‘S氨基和羧基末端的结构与功能之间， 细胞骨架的联合、周转和修补。这些实验是 预计将提供信息，帮助识别 脂蛋白-1‘S导致细胞表型改变的生化活性 并允许生成LMP-1如何可能的合理模型 在EVB介导的永生化中的作用。理解信号 EB病毒导致B细胞永生化的转导机制 提供对控制正常和 人B细胞恶性增殖状态，并可能为其研究提供依据 用于临床相关研究，旨在开发治疗 EBV依赖性淋巴瘤及其他疾病的预防和治疗 病毒和非病毒引起的恶性肿瘤。

Epstein-Barr Virus (EBV) is a human pathogen that is causally associated with both benign and malignant B-cell lymphoproliferations and nasopharyngeal carcinoma. Immunocompromised individuals such as AIDS patients and transplant recipients are at high risk for developing EBV- associated B-cell lymphomas. Virally-induced alterations of the growth properties of infected B-cells are likely to underlie EBV's contribution to these lymphoproliferative disorders. Infection of primary human B- cells in vitro EBV results in activation of the resting B-cell from a quiescent state to one of proliferation. These infected cells enter the cell cycle and are able to proliferate indefinitely and thus are immortalized. EBV is unique in its ability to immortalize primary resting B-cells in vitro. Entry of EBV-infected B-cells into the cell cycle and maintenance of the proliferative state of the cell is absolutely dependent upon viral gene expression. The overall aim of this proposal is to analyze the contribution of one particular gene product (LMP-1) of EBV to immortalization. The study of LMP-1 is of particular significance for the following reasons: 1) LMP-1 is one of 4 latent gene products, and the only membrane protein, shown to be essential for immortalization by EBV; ii) LMP-1 has profound effects on the growth of cells in culture (i.e., LMP-1 functions as an oncogene in rodent cells); iii) LMP-1 is located in the plasma membrane where it is associated, via its cytoplasmic amino- terminus, with the cytoskeleton. LMP-1 must interact with cell signal transduction pathways regulating normal B-cell proliferation and thus is the ideal starting point for identifying signaling pathways involved in immortalization by EBV. The specific objectives of this work are to use biochemical and genetic analyses of LMP-1 to: i) determine the transmembrane topology of LMP-1; ii) study the quaternary structure of LMP-1 and its relevance to function; and iii) determine the relationship between the structure of LMP-1's amino- and carboxy-termini and function, cytoskeletal association, turnover and patching. These experiments are expected to provide information that will aid in the identification of LMP-1's biochemical activity that results in altered cellular phenotypes and should allow the generation of rational models of how LMP-1 may function in EVB-mediated immortalization. Understanding the signal transduction mechanisms resulting B-cell immortalization by EBV will provide insights into the cellular mechanisms controlling the normal and malignant proliferative status of human B-cells, and may provide the basis for clinically relevant research aimed at the development of therapies for the prevention and treatment of EBV-dependent lymphomas as well as other virally and nonvirally induced malignancies.