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

项目概要/摘要 EB病毒（EBV）是一种几乎无处不在的经口传播的病原体，目前尚无疫苗。 初次感染后，大多数人无症状地携带病毒;然而， 免疫功能低下的个体，如HIV-1/AIDS感染者，可能导致 淋巴瘤这些包括非霍奇金淋巴瘤，如浆母细胞淋巴瘤、原发性中央淋巴瘤、淋巴瘤和淋巴瘤。 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，以及经典的 霍奇金淋巴瘤。总的来说，艾滋病毒感染者患非传染性疾病的相对风险要高出60-200倍。 霍奇金淋巴瘤和8-10倍高的相对风险发展霍奇金淋巴瘤相比， 未受感染的人。因此，预防EBV感染和/或消除EBV-1的安全和有效的疫苗， 风险的相关成分可能具有显著的临床益处，特别是在资源贫乏的地区， HIV-1是地方病。成功的疫苗通常是保护性的，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可以阻断EBV传播。以来 B细胞和上皮细胞都存在于鼻咽部，预防性EBV疫苗可能需要 引发可以阻断两种细胞感染的抗体。到目前为止，亚单位疫苗的努力集中在gp 350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 不介导膜融合的B细胞。gp 350疫苗的II期试验降低了 传染性单核细胞增多症，但未能防止感染。抗gp 350抗体可抑制EBV 感染B细胞，但大多数上皮细胞不表达补体受体。因此，gp 350不能 预防EBV感染的疫苗可能是由于它们不能引发中和EBV的抗体 上皮细胞感染。我们最近分离出一种单克隆抗体，AMMO 1，它与EBV gH/gL结合， 糖蛋白复合物，其是宿主细胞和病毒膜之间融合的重要调节剂。 AMMO 1以破坏膜融合并中和B和B区的EBV感染的方式结合gH/gL。 上皮细胞，原则上证明疫苗诱导的gH/gL抗体可能比 这些是针对GP 350的。该提案的目的是确定AMMO 1和其他抗EBV抗体的保护能力。 补充动物模型中抗EBV感染的单克隆抗体：携带EBV的人源化小鼠 人B细胞和幼年恒河猴中，其可以用EBV的恒河猴直系同源物口服感染。我们 我还将评估几种基于gH/gL的疫苗引发中和抗体的能力，并比较这些疫苗 在相关动物攻击模型中的基于gp 350的疫苗。这些研究将阐明抗体在 在预防EBV感染和疫苗开发方面发挥作用。此外，拟议的挑战研究， 幼年猕猴与非洲撒哈拉以南地区的目标人群高度相关， 发生在生命的前三年。

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.