EBV Entry and Spread in the Oral Cavity

描述（由申请方提供）：EB病毒（EBV）是一种经口传播的人类疱疹病毒，在全球几乎所有成年人中建立持续感染。病毒库在记忆B细胞群中处于潜伏状态，但目前的模型表明，它是通过终末分化浆母细胞中的零星再活化、上皮细胞中的扩增和B细胞库的再感染来补充的。EB病毒的长期携带可能与淋巴和上皮恶性肿瘤有关，免疫抑制的个体，特别是感染人类免疫缺陷病毒（HIV）的个体，发生这些恶性肿瘤的风险增加。这种风险增加的部分原因可能是病毒复制失控。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，正常平衡的紊乱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力学，特别是病毒如何在B细胞和上皮细胞之间传播以在宿主内扩增。五种EBV包膜蛋白gp 350、gH、gL、gp 42和BMRF 2与病毒进入B细胞和上皮细胞有差异。该实验室的新工作表明，上皮细胞的癌前变化可能使它们更容易受到感染，因为它们差异表达与gHgL和gp 350相互作用的重要细胞蛋白，并激活那些可以诱导相邻B细胞中病毒复制的细胞蛋白。此外，新鉴定的包膜蛋白BDLF 2与BMRF 2相互作用并可能依赖于BMRF 2，这可能与病毒传播有关。本应用程序的直接目标是测试这些假设。目的之一将使用可溶性形式的gHgL和？v？6，基于细胞的融合试验和表面等离子体共振，以评估之间的相互作用gHgL和？v？6在触发病毒-细胞融合中的作用。将探索额外的整合素可以介导相同功能的可能性，将检查gH与整合素结合对病毒细胞内运动的下游影响，并将测定整合素在体内正常和发育异常组织上的表达。目的二探讨CR2在提高上皮细胞感染效率中的作用。将评价CR2在体内发育异常上皮细胞上的表达，并通过比较全长和截短的CR2来确定gp 350刺激的与formins的相互作用对感染的影响。目的三将通过制备BDLF 2-null病毒和BMRF 2-null病毒来研究BMRF 2/BDLF 2复合物的作用。还将制备缺乏BMRF 2 RGD基序的病毒以探索gH和BMRF 2与整联蛋白结合的独特作用。EBV是与HIV疾病的口腔并发症相关的几种病毒之一，反映了其在口咽中的持续复制和脱落。揭示病毒靶向新感染细胞的机制对于理解发病机制和制定规避策略非常重要。公共卫生相关性：EB病毒（EBV）与几种不同的恶性肿瘤有关，人类免疫缺陷病毒感染者患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无法控制EBV在上皮细胞中的复制。该申请旨在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，并在此过程中寻求识别风险因素和潜在的新治疗靶点。

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.