Development of a Replicon RNA-based Vaccine against Dengue and Zika

摘要 该项目的长期目标是开发一种登革热-寨卡疫苗，以提供预防 登革热(DENV1-4)和寨卡(ZIKV)病毒的四种血清型具有最大的安全性和有效性。至 迄今为止，黄病毒疫苗的开发主要集中在诱导中和抗体(NAB)，如 它们被认为是预防自然感染的关键机制。然而， DENV和ZIKV的不同寻常之处在于，对疫苗接种或先前感染的弱抗体反应可能 在随后的感染和发病机制中诱导抗体依赖的增强(ADE) 再感染。事实上，有严重后遗症的DENV病已经在儿童中被记录下来，因为 目前只有获得许可的DENV疫苗。因此，此应用程序的主要目标是开发一个 不能介导ADE的DENV和ZIKV的有效疫苗。我们假设这种疫苗 需要同时激发强大的NAB反应和强大的T细胞效应器反应，以平衡 基于我们研究抗体和抗体之间相互作用的工作，任何ADE介导性抗体的存在 T细胞对DENV和ZIKV的应答。特别是，我们已经证明，CD8T细胞介导交叉- 对异型DENV和ZIKV感染的保护作用以及DENV疫苗诱导的CD8 T细胞 可以预防ADE。此外，我们的初步数据显示，一种基于RNA复制子的疫苗表达 ZIKV非结构蛋白3只诱导T细胞而不能诱导NAB反应并提供对ZIKV的保护作用 在老鼠身上挑战。因此，我们假设我们的DENV-ZIKV组合疫苗表达两种抗体-ZIKV。 而DENV1-4和ZIKV的T细胞靶向蛋白将产生体液和细胞免疫反应 提供针对所有五种病毒的强大、长期的保护。我们将通过以下方式验证这一假设： 具体目的如下：1)评价DENV-ZIKV疫苗的免疫原性和效力。2)至 确定DENV-ZIKV疫苗诱导保护的持久性和机制基础 豁免权。

ABSTRACT The long-term goal of this project is to develop a dengue-Zika vaccine that provides protection against the four serotypes of dengue (DENV1-4) and Zika (ZIKV) viruses with maximal safety and efficacy. To date, flavivirus vaccine development has focused on the induction of neutralizing antibodies (nAbs), as they have been assumed to be the key mechanism for protection against natural infection. However, DENV and perhaps ZIKV are unusual in that weak Ab responses to vaccination or prior infection can induce antibody-dependent enhancement (ADE) of infection and pathogenesis during subsequent reinfections. In fact, DENV disease with severe sequalae has been documented in children given the only currently licensed DENV vaccine. Thus, the primary objective of this application is to develop an effective vaccine against DENV and ZIKV that cannot mediate ADE. We hypothesize that this vaccine will need to elicit both strong nAb responses and strong T cell effector responses that will counterbalance the presence of any ADE-mediating Abs, based on our work investigating the interplay between Ab and T cell responses to DENV and ZIKV. In particular, we have shown that CD8 T cells mediate cross- protection against heterotypic DENV and ZIKV infections, and that DENV vaccine-elicited CD8 T cells can prevent ADE. In addition, our preliminary data show that an RNA replicon-based vaccine expressing ZIKV nonstructural protein 3 elicits only T cell but not nAb responses and confers protection against ZIKV challenge in mice. Thus, we hypothesize that our combinatorial DENV-ZIKV vaccine expressing both Ab- and T cell-targeting proteins of DENV1-4 and ZIKV will produce humoral and cellular immune responses that provide robust, long-term protection against all five viruses. We will test this hypothesis by achieving the following Specific Aims: 1) To evaluate immunogenicity and efficacy of a DENV-ZIKV vaccine. 2) To determine the durability and mechanistic underpinnings of DENV-ZIKV vaccine-induced protective immunity.