Defining the protective efficacy of antibodies against the EBV gH/gL glycoprotein complex

项目摘要/摘要 爱泼斯坦-巴尔病毒(EBV)是一种几乎无处不在的口腔传播病原体，目前还没有疫苗。 在初次感染之后，大多数人都没有症状地携带病毒；然而，在没有得到控制的情况下， 免疫功能受损的人，如艾滋病毒携带者/艾滋病患者，可能会导致 淋巴瘤。这些包括非霍奇金淋巴瘤，如浆母细胞淋巴瘤，原发中心性淋巴瘤 神经系统淋巴瘤、原发性渗出性淋巴瘤和弥漫性大B细胞淋巴瘤 霍奇金淋巴瘤。总体而言，艾滋病毒感染者患非艾滋病的相对风险高出60-200倍。 霍奇金淋巴瘤和发生霍奇金淋巴瘤的相对风险是 未受感染的个体。因此，一种安全有效的疫苗可以预防EBV感染和/或消除EBV- 相关的风险成分可能会有显著的临床益处，特别是在资源贫乏的地区 HIV-1是地方病。成功的疫苗通常具有保护性，因为它们会引发中和抗体。在… 目前尚不清楚预先存在的中和抗体是否能阻断EBV的传播。自.以来 鼻咽中同时存在B细胞和上皮细胞，预防性EBV疫苗可能需要 产生抗体，可以阻断这两种细胞类型的感染。到目前为止，亚单位疫苗的努力集中在gp350上。 与补体受体1和2结合并促进病毒粒子附着和内化的糖蛋白 由B细胞无介导膜融合。Gp350疫苗的二期试验降低了 传染性单核细胞增多症，但未能预防感染。抗gp350抗体可抑制EB病毒 感染B细胞，但大多数上皮细胞不表达补体受体。因此，gp350不能 预防EBV感染的疫苗可能是因为它们无法诱导出中和EBV的抗体 上皮细胞感染。我们最近分离到了一种与EBV Gh/Gl结合的单抗AMMO1 糖蛋白复合体，它是宿主细胞和病毒膜之间融合的重要调节因子。 AMMO1以破坏膜融合的方式与Gh/g1结合，并中和B和 从原理上讲，上皮细胞证明疫苗可以激发Gh/gl抗体，其效果可能比 那些反对gp350的人。这项提案的目标是定义AMMO1和其他抗EBV的保护能力 互补动物模型中抗EBV感染的单抗：人源化小鼠 人B细胞和婴儿恒河猴体内，可被口服感染EBV的恒河猴直系同源病毒。我们 还将评估几种基于Gh/gl的疫苗诱导中和抗体的能力，并比较这些 相关动物挑战模型中基于gp350的疫苗。这些研究将描绘出抗体的作用 在预防EBV感染方面发挥作用，并为疫苗开发提供信息。此外，拟议的挑战研究在 婴儿猕猴与撒哈拉以南非洲的目标人群高度相关，那里的EBV感染通常是 发生在生命的前3年。

PROJECT SUMMARY/ABSTRACT Epstein-Barr virus (EBV) is a nearly ubiquitous orally-transmitted pathogen for which there is no vaccine. Following primary infection, most individuals carry the virus asymptomatically; however, unchecked infection in immunocompromised individuals, such as those living with HIV-1/AIDS, can lead to the development of lymphomas. These include Non-Hodgkin's Lymphomas such as plasmablastic lymphoma, primary central nervous system lymphoma, primary effusion lymphoma and diffuse large B-cell lymphoma, as well as classic Hodgkin's lymphoma. Overall, HIV-infected individuals have a 60–200-fold higher relative risk to develop Non- Hodgkin's Lymphomas and an 8–10-fold higher relative risk to develop Hodgkin's Lymphoma compared to uninfected individuals. Thus, a safe and effective vaccine that prevents EBV infection and/or eliminates the EBV- associated component of risk could have a significant clinical benefit, particularly in resource-poor areas where HIV-1 is endemic. Successful vaccines are usually protective because they elicit neutralizing antibodies. At present it is not currently known whether pre-existing neutralizing antibodies can block EBV transmission. Since both B cells and epithelial cells are present in the nasopharynx, a preventative EBV vaccine would likely need to elicit antibodies that can block infection of both cell types. To date, subunit vaccine efforts focused on the gp350 glycoprotein which binds to complement receptors 1 and 2 and promotes attachment and internalization of virions by B cells without mediating membrane fusion. A phase II trial of a gp350 vaccine reduced the incidence of infectious mononucleosis but failed to protect against infection. Antibodies against gp350 can inhibit EBV infection of B cells, but most epithelial cells do not express complement receptors. Thus, the inability of gp350 vaccines to protect against EBV infection may be due to their inability to elicit antibodies that neutralize EBV infection of epithelial cells. We recently isolated a monoclonal antibody, AMMO1 that binds to the EBV gH/gL glycoprotein complex, which is an important regulator of fusion between the host cell and viral membranes. AMMO1 binds to gH/gL in a manner that disrupts membrane fusion and neutralizes EBV infection of both B and epithelial cells demonstrating, in principle, that vaccine elicited gH/gL antibodies could be more efficacious than those against gp350. The goal of this proposal is to define the protective capacity of AMMO1 and other anti-EBV monoclonal antibodies against EBV infection in complementary animal models: humanized mice that harbor human B cells and in infant rhesus macaques, which can be orally infected with the rhesus ortholog of EBV. We will also evaluate the ability of several gH/gL-based vaccines to elicit neutralizing antibodies and compare these gp350-based vaccines in relevant animal challenge models. These studies will delineate the role that antibodies play in preventing EBV infection and inform vaccine development. Moreover, the proposed challenge studies in infant macaques are highly relevant to the target-population in Sub-Sharan Africa where EBV infection normally occurs in the first 3 years of life.