Dengue virus mRNA lipid nanoparticle vaccine

每年有近4亿人通过受感染蚊子的叮咬感染登革热病毒（DENV） 集中在世界的热带和亚热带地区。症状可以从发热性疾病， 严重的登革热，表现为血浆泄漏、血压突然下降、器官衰竭和休克， 最终会导致死亡严重的登革热并发症通常与继发性异型增生有关。 感染四种循环血清型之一。在这种情况下，针对交叉免疫的体液免疫反应， 反应性的、中和性差的表位通过抗体依赖性的免疫调节导致易感细胞的感染性增加。 增强（ADE）。此外，DENV免疫力与寨卡病毒易感性增加有关 通过ADE。目前还没有可用的治疗方法来对抗DENV疾病。Dengvaxia，唯一的 已获得许可的DENV疫苗，被发现会增加初治人群的住院率，因此不适合 推荐给大部分高危人群。迫切需要一种安全有效的疫苗 其产生对所有四种DENV血清型的稳健、平衡、中和应答。我们打算写一部小说 利用紧急平台的DENV疫苗：脂质中包埋的病毒蛋白的mRNA编码 纳米颗粒（LNP）。mRNA-LNP疫苗以安全， 非传染性平台此外，我们可以通过以下方式将宿主免疫应答导向中和表位： 突变编码病毒蛋白的mRNA。我们假设一个序列工程四价 mRNA-LNP疫苗将诱导针对所有四种血清型的平衡的保护性免疫应答。 登革热，而不可能导致免疫增强和ADE。在本研究的目标1中，我们将 产生并优化编码所有病毒的前膜和包膜病毒糖蛋白的mRNA构建体， DENV的四种血清型。我们会突变那些中和性差，交叉反应的表位，这些表位会导致ADE。在Aim中 我们将在小鼠模型中描述对疫苗的免疫应答。除了定量体液 和细胞免疫反应，我们还将衡量所有疫苗的免疫增强能力。在Aim中 3，我们将通过挑战接种疫苗的小鼠，在易感小鼠模型中评估疫苗的有效性和安全性 用不同的DENV血清型来监测保护和ADE。我们还将确定保护机制 通过过继转移实验。通过这项研究，我们将确定DENV疫苗， 保护和缺乏免疫增强，用于作为候选人疫苗的进一步评价。

Nearly 400 million people are infected with dengue virus (DENV) each year through the bite of infected mosquitos concentrated in the tropical and subtropical regions of the world. Symptoms can range from febrile illness to severe dengue that manifests as plasma leakage, sudden loss of blood pressure, organ failure, and shock that can ultimately lead to death. Severe dengue complications are often associated with a secondary heterotypic infection of one of the four circulating serotypes. In this scenario, humoral immune responses targeting cross- reactive, poorly-neutralizing epitopes lead to increased infectivity of susceptible cells via antibody-dependent enhancement (ADE). Additionally, DENV immunity has been implicated in increased susceptibility to Zika virus through ADE. Currently there are no available therapeutics to combat DENV disease. Dengvaxia, the only licensed DENV vaccine, was found to increase hospitalization rates in naïve populations, and thus is not recommended for a large portion of at-risk individuals. There is an urgent need for a safe and efficacious vaccine that elicits a robust, balanced, neutralizing response to all four DENV serotypes. We propose to develop a novel DENV vaccine utilizing an emergent platform: mRNA encoding for viral proteins encapsidated in a lipid nanoparticle (LNP). mRNA-LNP vaccines elicit robust humoral and cell-mediated immune responses in a safe, non-infectious platform. Additionally, we can direct the host immune response towards neutralizing epitopes by mutating the mRNA encoding for the viral protein. We hypothesize that a sequence-engineered tetravalent mRNA-LNP vaccine will induce a balanced, protective immune response against all four serotypes of dengue without the potential of causing immune enhancement and ADE. In Aim 1 of this study we will generate and optimize mRNA constructs encoding for the pre-membrane and envelope viral glycoproteins for all four serotypes of DENV. We will mutate the poorly-neutralizing, cross-reactive epitopes that drive ADE. In Aim 2 we will characterize the immune response to the vaccines in a mouse model. In addition to quantifying humoral and cellular immune responses, we will also measure the immune enhancement capacity of all vaccines. In Aim 3, we will evaluate vaccine efficacy and safety in susceptible mouse models, by challenging vaccinated mice with different DENV serotypes to monitor protection and ADE. We will also determine mechanism of protection via adoptive transfer experiments. Through this study, we will identify DENV vaccines that demonstrate broad protection and lack of immune enhancement for further evaluation as candidate human vaccines.