Innate Immune Recognition Enhances Flavivirus Vaccine Efficacy

先天免疫识别增强黄病毒疫苗功效

• 批准号: 7905119
• 负责人: Gregg N. Milligan
• 金额: $ 59.94万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7905119
• 关键词: Address; Animals; Antibodies; Antibody Formation; Antigens; B-Lymphocytes; Bone Marrow; CD8B1 gene; Categories; Cells; Chemicals; Defect; Dendritic Cells; Dengue; Development; Disease; Encephalitis; Flavivirus; Flavivirus Infections; Gene Expression; Genes; Genome; Human; Immune; Immune Cell Activation; Immune response; Immunity; Infection; Interferon Receptor; Interferon Type I; Interferons; Lead; Learning; Link; Methods; Mus; Names; Normal Cell; Pathway interactions; Pattern recognition receptor; Process; Production; RNA; Replicon; Resources; Role; System; T cell response; T memory cell; T-Lymphocyte; Vaccination; Vaccines; Viral; Virion; Virus; Virus Diseases; West Nile virus; adaptive immunity; base; cell type; cytokine; in vivo; insight; lymph nodes; macrophage; member; multidisciplinary; particle; pathogen; protein kinase R; receptor binding; response; tool; type I interferon receptor; uptake; vaccine candidate; vaccine efficacy; viral RNA

DESCRIPTION (provided by applicant): Flaviviruses populate the NIAID's Category A, B, and C lists of viruses. Vaccines are urgently needed for multiple flavivirus diseases, notably dengue and West Nile encephalitis. To develop more effective vaccines a comprehensive understanding of how flaviviruses trigger immune responses is needed. To address this need, we developed single-cycle flaviviruses and packaging cell systems that produce them at high titers. These single-cycle viruses include West Nile virus (WNV) -derived viral replicon particles (VRPs) and a WN encephalitis vaccine candidate named Replivax. Both particles encode self-replicating WNV RNA genomes (replicons) deficient in one or more genes required for genome packaging. VRPs and Replivax mimic many aspects of WNV infection (receptor binding, uptake, RNA release, and genome replication). However, VRPs and Replivax cannot produce progeny virions in normal cells, and hence are not pathogenic. Nevertheless, Replivax encodes a protective immunogen, the sub-viral particle (SVP), and has proven to be a remarkably potent vaccine candidate. VRPs can be modified to express marker genes (to allow tracking in vivo), further enhancing their utility. Our single-cycle particles target the draining lymph nodes of mice, where they infect macrophages and induce high levels of type I interferon (IFN), suggesting that IFN is critical for directing the adaptive immune response to our vaccine. However, mice deficient in type I IFN receptors produced antibody responses to Replivax indistinguishable from WT animals, suggesting that IFN was not linking innate and adaptive immunity. In the process of learning how WNV induces IFN, we examined how ex vivo cultures of murine bone marrow-derived dendritic cells responded to WNV VRP infection. These studies showed that protein kinase R (PKR) appeared to be acting as a pattern-recognition receptor (PRR) that triggered IFN synthesis. Further, VRP-inoculated PKR-deficient mice produced lower levels of IFN and lower levels of WNV-specific antibodies than WT mice, indicating that PRR pathways (PRRPs) control both innate and adaptive responses. Based on these studies we hypothesize that: Recognition of Replivax via PRRs results in the engagement of multiple PRRPs, which may act independently, or in concert, to induce innate and adaptive immunity. This hypothesis will be evaluated in 3 specific aims in which we will elucidate the effect of macrophage depletion and deficiencies in specific PRRPs on the 1) innate, 2) humoral, and 3) cellular immune response in mice inoculated with these unique single-cycle flavivirus particles.

描述(由申请人提供)：黄病毒填充NIAID的A、B和C类病毒列表。对于多种黄病毒疾病，特别是登革热和西尼罗河脑炎，迫切需要疫苗。为了开发更有效的疫苗，需要全面了解黄病毒如何触发免疫反应。为了满足这一需求，我们开发了单周期黄病毒和包装细胞系统，以高滴度生产它们。这些单周期病毒包括西尼罗河病毒(WNV)衍生的病毒复制子颗粒(VRP)和一种名为Replivax的WN脑炎候选疫苗。这两种粒子都编码自我复制的西尼罗河病毒RNA基因组(复制子)，该基因组缺乏基因组包装所需的一个或多个基因。VRPs和Replivax模拟西尼罗河病毒感染的许多方面(受体结合、摄取、RNA释放和基因组复制)。然而，VRPs和Replivax不能在正常细胞中产生后代病毒粒子，因此不是致病的。然而，Replivax编码一种保护性免疫原亚病毒颗粒(SVP)，并已被证明是一种非常有效的候选疫苗。VRP可以被修饰以表达标记基因(以允许在体内进行跟踪)，从而进一步增强它们的实用性。我们的单周期颗粒以小鼠的引流淋巴结为靶点，在那里它们感染巨噬细胞并诱导高水平的I型干扰素(干扰素)，这表明干扰素对于引导对我们疫苗的适应性免疫反应至关重要。然而，缺乏I型干扰素受体的小鼠对Replivax产生了与WT动物难以区分的抗体反应，这表明干扰素没有将先天免疫和获得性免疫联系起来。在了解西尼罗河病毒如何诱导干扰素的过程中，我们检测了体外培养的小鼠骨髓来源的树突状细胞对西尼罗河病毒VRP感染的反应。这些研究表明，蛋白激酶R(PKR)似乎是一种模式识别受体(PRR)，可以触发干扰素的合成。此外，与WT小鼠相比，接种VRP的PKR缺陷小鼠产生的干扰素水平和WNV特异性抗体水平都较低，这表明PRR途径(PRRP)控制着先天和获得性反应。基于这些研究，我们假设：通过PRRs识别Replivax导致了多个PRRP的参与，这些PRRP可能独立地或协同地作用，以诱导先天免疫和获得性免疫。这一假说将在三个具体目标上进行评估，其中我们将阐明巨噬细胞耗尽和特定PRRP缺陷对接种这些独特的单循环黄病毒颗粒的小鼠的1)先天、2)体液和3)细胞免疫反应的影响。