Synthetic nanoparticle vaccines for RSV

描述(申请人提供)：呼吸道合胞病毒(RSV)是导致婴儿和老年人严重下呼吸道疾病的最重要原因。尽管经过几十年的努力，目前还没有批准的疫苗。早期试图开发福尔马林灭活疫苗(FI-RSV)的结果是在环境中暴露于RSV后疾病得到加强。由于免疫原性差和反应时间短，开发重组亚单位疫苗的努力取得的成功有限。在过去的几年里，一些研究途径表明，与RSV感染相关的不良炎症反应，以及FI-RSV疫苗的失败，与RSV-G蛋白有关，RSV-G蛋白在病毒与靶细胞的附着中发挥关键作用。RSV-G包含一个CX3C趋化因子基序，该基序与CX3CR1趋化因子受体相互作用，似乎诱导了一种以Th2为导向的炎性免疫反应，从而促进了疾病的发病。我们已经证明，对CX3C基序的抗体反应可以降低病毒的感染性，抑制RSV-G趋化因子的调节活性，并减少感染后的肺部炎症。诱导干扰素应答的疫苗设计也可能有助于减少与呼吸道合胞病毒感染相关的Th2偏向应答和肺部炎症。在这个第一阶段的项目中，我们将使用一种创新的方法来生产合成纳米颗粒疫苗，该疫苗携带RSV-G肽与RSV T细胞靶抗原结合，有利于干扰素应答。纳米粒子将通过逐层(LBL)沉积相反电荷的多肽(包括携带抗原有效载荷的设计肽(DP))来制备，以在固体纳米核心上构建超薄膜。我们已经证明，用这种策略制造的疫苗可以提高T细胞和抗体靶位的免疫原性，而不会引发不良炎症反应。目前的建议将(1)确定用于增加纳米粒载量和稳定性的最佳DP设计，(2)基于抗体和诱导的T细胞反应的效力和表型选择LBL纳米粒疫苗设计(特别强调已被证明可提高对RSV疾病的保护作用的干扰素反应)，以及(3)在检测病毒和趋化因子的中和、抑制趋化作用和保护小鼠免受RSV攻击后的病毒负荷和肺部炎症的检测中，测试抗体反应的生物活性。RSV-G DP将包括一个与趋化因子基序重叠的CD4T细胞表位，并将补充来自RSV-M2或RSV-F的T细胞靶标表位，以提供额外的干扰素对Th1/Th2平衡的调节。因此，这项研究中生产的新型纳米疫苗将能够诱导多种机制来预防RSV感染和异常的肺部炎症。该项目的成果是一个或多个在动物模型中证明了安全性和有效性的LBLRSV-G候选疫苗；这些候选疫苗将在随后的第二阶段项目中进一步开发，该项目将完成研究新药申请提交和最终临床测试所需的步骤。将这一创新方法应用于RSV疫苗开发也将影响其他传染病的疫苗开发。 与公共卫生相关：该项目将使用一种创新的纳米颗粒技术来生产呼吸道合胞病毒的新型候选疫苗。由于疫苗含有同时导致感染和宿主炎症的部分病毒，疫苗诱导的免疫反应不仅将降低RSV的传染性，还将缓解与RSV疾病相关的肺部炎症。从这一努力中产生的一种疫苗将解决婴儿、儿童、老年人和免疫受损患者的大量未得到满足的需求。

DESCRIPTION (provided by applicant): Respiratory syncytial virus (RSV) is the most important cause of severe lower respiratory tract illness in infants and the elderly. There is no approved vaccine despite decades of effort. Early attempts to develop a formalin- inactivated vaccine (FI-RSV) resulted in disease enhancement following environmental exposure to RSV. Efforts to develop recombinant subunit vaccines have met with limited success due to poor immunogenicity and short-lived responses. Over the last few years, several avenues of study have suggested that the adverse inflammatory responses associated with RSV infection, and perhaps the failure of the FI-RSV vaccine, are linked to the RSV-G protein which plays a critical role in virus attachment to target cells. RSV-G contains a CX3C chemokine motif that interacts with the CX3CR1 chemokine receptor and appears to elicit an inflammatory Th2-biased immune response that contributes to disease pathogenesis. We have shown that antibody responses to the CX3C motif can reduce virus infectivity, inhibit RSV-G chemokine-modulating activity and reduce lung inflammation following infection. Vaccine designs that elicit an IFN response may also help to reduce the Th2-biased response and lung inflammation associated with RSV infection. In this Phase I project, we will use an innovative approach to produce synthetic nanoparticle vaccines carrying the RSV-G peptide coupled with RSV T-cell target antigens that favor IFN responses. Nanoparticles will be fabricated using layer-by-layer (LbL) deposition of oppositely charged polypeptides, including designed peptides (DP) carrying the antigen payload, to build ultrathin films on solid nano-sized cores. We have shown that vaccines made by this strategy improve the immunogenicity of both T-cell and antibody target epitopes without triggering adverse inflammatory reactions. The current proposal will (1) identify the optimal DP designs for increasing loading and stability of nanoparticles, (2) select LbL nanoparticle vaccine designs based on potency and phenotype of antibody and T-cell responses induced (with particular emphasis on IFN responses that have been shown to improve protection from RSV disease), and (3) test the biological activity of antibody responses in assays measuring virus and chemokine neutralization, inhibition of chemotaxis, and protection of mice from viral burden and lung inflammation following challenge with RSV. The RSV-G DP will include a CD4 T-cell epitope that overlaps the chemokine motif, and will be complemented by addition of T-cell target epitopes from RSV-M2 or RSV-F to provide additional IFN modulation of the Th1/Th2 balance. Thus, the novel nanoparticle vaccines produced in this study will have the capacity to elicit multiple mechanisms of protection against RSV infection and aberrant lung inflammation. The deliverable of this project is one or more LbL RSV-G vaccine candidates with demonstrated safety and efficacy in animal models; these candidates will be further developed in a subsequent Phase II project that will complete the steps necessary for Investigational New Drug application filing and eventual clinical testing. The application of this innovative approach to RSV vaccine development will also impact vaccine development for other infectious diseases. PUBLIC HEALTH RELEVANCE: This project will use an innovative nanoparticle technology to produce novel vaccine candidates for respiratory syncytial virus. Since the vaccines contain a portion of the virus responsible for both infection and host inflammation, vaccine-induced immune responses will not only reduce the rate of RSV infectivity but will also alleviate the lung inflammation associated with RSV disease. A vaccine emerging from this effort will address a large unmet need in infants, children, elderly and immunocompromised patients.