EBV Entry and Spread in the Oral Cavity

描述(申请人提供)：爱泼斯坦-巴尔病毒(EBV)是一种经口腔传播的人类疱疹病毒，在全球几乎所有成年人中都会持续感染。病毒储存库在记忆B细胞群体中处于潜伏状态，但目前的模型表明，通过终末分化的浆母细胞的零星重新激活、上皮细胞的扩增和B细胞池的再次感染来补充病毒储存库。EBV的长期携带可能与淋巴系和上皮性恶性肿瘤有关，免疫抑制的人，特别是那些感染了人类免疫缺陷病毒(HIV)的人，患上这种疾病的风险更高。这种增加的风险可能部分反映了对病毒复制的失去控制。EBV在肿瘤发生中的作用是复杂的，但血清流行病学研究表明，正常平衡的破坏和病毒载量的增加先于恶性肿瘤的出现。这项研究的长期目标是了解感染的动态，特别是病毒在B细胞和上皮细胞之间的交通如何在宿主内放大。五种EBV包膜蛋白gp350、Gh、g1、GP42和BMRF2与病毒进入B细胞和上皮细胞有关。该实验室的新工作表明，上皮细胞的癌前病变可能使它们更容易受到感染，因为它们不同地表达对与gHgL和gp350相互作用至关重要的细胞蛋白，并激活那些可以在相邻B细胞中诱导病毒复制的蛋白。此外，新发现的与BMRF2相互作用并可能依赖于BMRF2的包膜蛋白BDLF2可能与病毒传播有关。这个应用程序的直接目标是测试这些假设。目的利用gHgL和v6的可溶性形式、细胞融合实验和表面等离子体共振技术评价gHgL和v6在触发病毒-细胞融合过程中的相互作用。此外，还将探讨其他整合素是否可以介导同样的功能，Gh与整合素结合对病毒细胞内运动的下游影响，以及体内正常和发育不良组织中整合素的表达情况。目的二探讨CR2在提高上皮细胞感染效率中的作用。将评估体内发育不良上皮细胞上CR2的表达，并通过比较全长和截短CR2来确定gp350刺激的与福尔马林相互作用对感染的影响。目的通过构建BDLF2缺失病毒和BMRF2缺失病毒，研究BMRF2/BDLF2复合体的作用。缺乏BMRF2 RGD基序的病毒也将被用来探索Gh和BMRF2与整合素结合的独特效应。EBV是与HIV疾病口腔并发症有关的几种病毒之一，反映了其在口咽部的持续复制和脱落。解开病毒针对新感染细胞的机制对于理解发病机制和制定规避策略具有重要的公共卫生意义：EB病毒(EBV)与几种不同的恶性肿瘤有关，携带人类免疫缺陷病毒的人患上这些疾病的风险增加。这种风险增加的部分原因可能是免疫系统未能控制EBV在上皮细胞中的复制。这项应用试图了解病毒和细胞蛋白之间的相互作用，使病毒能够进入上皮细胞并启动复制，并在这样做的过程中寻求确定风险因素和潜在的新的治疗靶点。

DESCRIPTION (provided by applicant): Epstein-Barr virus (EBV) is an orally-transmitted human herpesvirus that establishes persistent infections in almost all adults worldwide. The reservoir of virus is in a latent state in the memory B cell population but current models suggest that it is replenished by sporadic reactivation in terminally differentiating plasmablasts, amplification in epithelial cells and reinfection of the B cell pool. Long term carriage of EBV can be associated with both lymphoid and epithelial malignancies and individuals who are immunosuppressed, particularly those infected with the human immunodeficiency virus (HIV), are at increased risk of developing them. Part of this increased risk may reflect a loss of control of replication of virus. The role that EBV plays in tumorigenesis is complex, but seroepidemiologic studies suggest that the disturbance of the normal equilibrium and an increase in virus load precedes the appearance of malignancy. The long term goal of this research is to understand the dynamics of infection, particularly how virus traffics between B cells and epithelial cells to amplify within the host. Five EBV envelope proteins have been differentially implicated in virus entry into B cells and epithelial cells, gp350, gH, gL, gp42 and BMRF2. New work from this laboratory suggests that preneoplastic changes in epithelial cells may make them more susceptible to infection as they differentially express cell proteins important for interaction with gHgL and gp350 and activate those that can induce virus replication in adjacent B cells. Further, that a newly identified envelope protein, BDLF2, which interacts with and may be dependent on BMRF2 may be relevant to virus spread. The immediate goals of this application are to test these hypotheses. Aim one will use soluble forms of gHgL and ?v?6, cell-based fusion assays and Surface Plasmon Resonance to evaluate interactions between gHgL and ?v?6 in triggering virus-cell fusion. The possibility that additional integrins can mediate the same function will be explored, the downstream effects of gH binding to integrins on intracellular movement of virus will be examined and the expression of integrins on normal and dysplastic tissues in vivo will be determined. Aim two will explore the role that CR2 plays in increasing efficiency of epithelial cell infection. Expression of CR2 on dysplastic epithelial cells in vivo will be evaluated and the effects on infection of a gp350-stimulated interaction with formins will be determined by comparison of full length and truncated CR2. Aim three will investigate the role of the BMRF2/BDLF2 complex by making a BDLF2-null virus and a BMRF2-null virus. A virus lacking the BMRF2 RGD motif will also be made to explore unique effects of gH and BMRF2 binding to integrins. EBV is one of a several viruses associated with oral complications of HIV disease reflecting its continued replication and shedding in the oropharynx. Unraveling mechanisms by which virus is targeted to cells newly prone to infection is important to understanding pathogenesis and developing evasive strategies PUBLIC HEALTH RELEVANCE: Epstein-Barr virus (EBV) is associated with several different malignancies and individuals with the human immunodeficiency virus are at increased risk of developing them. Part of this increased risk may represent a failure of the immune system to control EBV replication in epithelial cells. This application seeks to understand the interactions between virus and cell proteins that enable virus to enter epithelial cells and initiate replication and in doing so seeks to identify risk factors and potential novel therapeutic targets.