Neutralizing Antibodies in Acute and Persistent Epstein-Barr Virus Infection

 描述（由申请人提供）：我们的目标是更好地了解EB病毒如何感染人类，以开发更有效的治疗方法来预防或治疗EBV诱导的疾病。具体而言，该项目的重点是如何中和抗体，无论是阻断B或上皮细胞EBV感染影响急性和持续感染的主机后，经口传播。EBV通过不同的病毒蛋白和受体感染B细胞和上皮细胞，但哪些细胞类型对口腔感染和病毒扩增的初始阶段至关重要尚不清楚。更重要的是，中和B细胞感染正在被作为EBV疫苗的基础，几乎没有临床前或临床数据来支持针对B细胞的EBV感染的中和抗体将对口服病毒攻击具有任何影响的概念。 我们在最准确的EBV感染动物模型中使用中和抗体作为探针，以询问单独的免疫应答是否足以破坏口服病毒攻击后的急性和持续感染。72 A1是仅有的几种已知的EBV中和性单克隆抗体（mAb）中研究最多的，并且其结合EBV主要膜糖蛋白gp 350以抑制EBV附着于B细胞。为了在用于EBV感染的恒河猴动物模型中使用72 A1，我们用EBV gp 350替换恒河猴淋巴隐病毒（rhLCV）中的天然gp 350基因。这种嵌合病毒可以被72 A1中和并感染恒河猴，为直接在体内研究EBV gp 350特异性试剂提供了一种新的动物模型。上皮细胞感染是由EB病毒糖蛋白的结合介导的 H和L与整合素复合。gH和gL在rhLCV中更为保守，并且一种有效的中和mAb E1 D1（可防止上皮细胞感染）与rhLCV gH/gL上的整联蛋白结合位点发生交叉反应。这些中和单克隆抗体将用于实验性检测B和上皮细胞感染在恒河猴口服嵌合病毒后急性和持续感染中的作用。 这项提议的一个重要优势是它促进了我们对EBV生物学的基本理解，以及它的直接翻译影响。更好地理解EBV感染后的早期事件和实验测试的作用，无论是针对B或上皮细胞感染的中和抗体的口服传播和EBV疫苗的开发提供了一个基础上的机制，而不是试错。此外，这些研究可以提供重要的临床前数据，以促进中和单克隆抗体作为预防免疫抑制的EBV初治宿主中EBV诱导的疾病的治疗剂的使用。

 DESCRIPTION (provided by applicant): Our goal is to better understand how Epstein-Barr virus infects humans in order to develop more effective therapeutics that prevent or treat EBV-induced diseases. Specifically, this project focuses on how neutralizing antibodies that block either EBV infection of B or epithelial cells impact acute and persistent infection of the host aftr oral transmission. EBV infects B cells and epithelial cells through different viral proteins and receptors, but which cell types are critical for the initial phases of oral infection and viral amplification are unknown. More importantly, neutralizing B cell infection is being pursued as the basis for an EBV vaccine with little pre-clinical or clinical data to support the concept that neutralizing antibodies against EBV infection of B cells will have any impact on oral virus challenge. We use neutralizing antibodies as a probe in the most accurate animal model for EBV infection to ask whether this arm of the immune response alone is sufficient to disrupt acute and persistent infection upon oral virus challenge. 72A1 is the most studied of only a few known EBV neutralizing monoclonal antibodies (mab), and it binds the EBV major membrane glycoprotein, gp350, to inhibit EBV attachment to B cells. In order to use 72A1 in the rhesus macaque animal model for EBV infection, we replaced the native gp350 gene in the rhesus lymphocryptovirus (rhLCV) with EBV gp350. This chimeric virus can be neutralized by 72A1 and infects rhesus macaques, providing a novel animal model for studying EBV gp350-specific reagents directly in vivo. Epithelial cell infection is mediated by binding of the EBV glycoprotein H and L complex to integrins. gH and gL are much more well conserved in rhLCV and a potent neutralizing mab, E1D1, that prevents epithelial cell infection cross-reacts with the integrin binding site on rhLCV gH/gL. These neutralizing mabs will be used to experimentally test the role of B and epithelial cell infection in acute and persistent infection after oral challenge withthe chimeric virus in rhesus macaques. An important strength of this proposal is its advancement of our basic understanding of EBV biology, as well as its immediate translational impact. Better understandings of the early events in EBV infection after oral transmission and experimental testing for the role of neutralizing antibodies targeting either B or epithelial cell infection proide a foundation for EBV vaccine development based on mechanism, rather than trial and error. In addition, these studies can provide important pre-clinical data to advance the use of neutralizing mabs as a therapeutic to prevent EBV-induced disease in immunosuppressed, EBV-naive hosts.