Design of a human monoclonal antibody-informed dengue vaccine

描述(申请人提供)：尽管登革热是最重要的蚊子传播的病毒疾病，但目前还没有登革热疫苗。登革病毒(DENV)有四种不同的血清型，针对一种血清型的交叉反应抗体可以增强其他血清型对携带Fc受体的细胞的感染，如与人类严重疾病相关的巨噬细胞。安全有效的疫苗应诱导针对所有四种DENV血清型的强大交叉保护性中和抗体，同时将只会增加感染和疾病严重程度的非中和交叉反应抗体降至最低。因此，一种理想的疫苗应该只包括那些会产生强烈中和抗体的抗原区，而不应该包括产生非中和抗体的抗原区。该项目的中心目标是调查一种假设，即只包含那些将诱导强烈的、广泛中和的DENV抗体反应的表位的疫苗将是安全和有效的。为了实现这一中心目标，该项目建议改变目前的DENV疫苗研究范式，方法是使用从针对表面E蛋白的独特的人类抗DENV单抗的研究中获得的见解来设计、表征和在小鼠模型中测试嵌合疫苗。第一个具体目标是设计含有DENV表位的黄病毒E蛋白嵌合体，并鉴定它们的折叠、组装和功能。由于我们与人的单抗的结果表明，重要的中和DENV表位是构象敏感的，一种相关的黄病毒，黄热病将被用作构建嵌合体的支架。我们将把特定的DENV表位引入到黄热病17D疫苗株E蛋白中，产生嵌合的E蛋白、病毒样颗粒和传染性病毒，并确定这些E蛋白嵌合体是否仍能被我们的人抗DENV单抗识别。第二个特异性目的是在小鼠模型中评价含有DENV表位的黄病毒E蛋白嵌合体的抗原性，并在体外检测血清中是否存在结合、中和和增强的抗DENV抗体。第三个具体目的是确定含有DENV表位的黄病毒E蛋白嵌合体是否会在小鼠DENV攻击模型中产生保护性免疫反应。利用广泛接受的DENV感染小鼠模型，提出了用DENV感染的感染性挑战。这些目标的成功完成将创造出一种DENV疫苗，它将诱导广泛的中和抗体反应，同时最大限度地减少非中和、增强抗体反应的诱导，将疫苗接受者患更严重疾病的风险降至最低。

DESCRIPTION (provided by applicant): Despite being the most important mosquito-transmitted viral disease, there is currently no vaccine for dengue. There are four distinct serotypes of dengue virus (DENV) and cross reactive antibodies to one serotype can enhance infection of other serotypes into Fc receptor-bearing cells such as macrophages correlating with severe disease in humans. A safe and effective vaccine should induce strong, cross protective neutralizing antibodies against all four DENV serotypes, while minimizing non-neutralizing cross reactive antibodies that will only serve to enhance infection and disease severity. Therefore, an optimal vaccine should include only those antigenic regions that will induce strongly neutralizing antibodies and none of the antigenic regions that induce non-neutralizing antibodies. The central aim of this project is to investigate the hypothesis that a vaccine containing only those epitopes that will induce a strong, broadly neutralizing DENV antibody response will be safe and effective. To accomplish this central aim, this project proposes to shift the current paradigm of DENV vaccine research by using insights derived from the study of unique human monoclonal anti-DENV antibodies against the surface E protein to design, characterize, and test a chimeric vaccine in a mouse model. The first specific aim is to design flavivirus E protein chimeras containing DENV epitopes, and characterize their folding, assembly, and functionality. As our results with human MAbs indicate that the important neutralizing DENV epitopes are conformationally sensitive, a related flavivirus, yellow fever will be used as a scaffold for constructing the chimeras. We will introduce specific DENV epitopes into the yellow fever 17D vaccine strain E protein, generate chimeric E protein, virus- like particles, and infectious virus and determine whether these E protein chimeras are still recognized by our human anti-DENV monoclonal antibodies. The second specific aim is to evaluate the antigenicity of flavivirus E protein chimeras containing DENV epitopes in a mouse model and assay serum for the presence of binding, neutralizing, and enhancing anti-DENV antibodies in vitro. The third specific aim is to determine if flavivirus E protein chimeras containing DENV epitopes will produce a protective immunological response in a mouse DENV challenge model. Infectious challenge with DENV is proposed using a widely accepted murine model of DENV infection. Successful completion of the aims will create a DENV vaccine that will induce a broadly neutralizing antibody response, while minimizing the induction of a non-neutralizing, enhancing antibody response, minimizing the risk of more severe disease in vaccine recipients.