Parainfluenza virus 3 interactions with dendritic cells

描述(由申请人提供)： 尽管经过了几十年的研究，但RSV和副流感等副粘病毒的免疫生物学仍然知之甚少，也是一个激烈争议的主题。这一知识差距阻碍了安全有效的疫苗和抗病毒战略的发展。树突状细胞(DC)是诱导CTL应答病毒的最有效的抗原提呈细胞。对DC功能的干扰，是由病毒进化而来的一种机制，目的是破坏宿主的防御并在免疫反应中存活下来。这项应用的总体目标是确定人类副流感病毒与树突状细胞(DC)的体外相互作用。HPF3感染可促进DC成熟，同时反常干扰其正常的抗原提呈功能。最近的数据表明，病毒表面糖蛋白血凝素神经氨酸酶(HN)和融合蛋白(F)可能介导了这些作用。我们的总体假设是，呼吸道粘膜感染后不久与DC的相互作用是HPF3免疫和发病的关键决定因素。HN和F介导的DC功能紊乱和细胞反应受损可能是未能建立持久保护性免疫的原因之一。我们的第一个目标是确定病毒糖蛋白对体外培养的人树突状细胞分化成熟的影响。我们将剖析HN和F的具体贡献，并确定HN的特定功能是否会对这一过程产生不同的影响。我们将在通过内皮细胞迁移的组织培养模型中分析HPF3感染-以及接触病毒糖蛋白-如何影响单核细胞向DC的迁移和分化。这个模型使我们能够研究病毒病原体如何在组织环境中调节DC，更接近于在人类呼吸道粘膜中发现的自然条件。我们的第二个目标是在体外分析HN和F在DC与T细胞相互作用中的免疫调节作用。我们将确定在体外，HN和/或F是否可以通过直接细胞接触依赖机制来解释感染HPF3的DC刺激特性的损害。此外，我们将确定感染是否诱导DC将T淋巴细胞极化为Th2或Th1型细胞因子的表达，以及HN和F是否是这种极化的关键决定因素。 病毒糖蛋白的定义(S)及其与树突状细胞调控相关的功能将有助于通过产生更安全和更有效的重组形式的HPF3来进行疫苗开发。对HPF3介导的免疫调节重要的病毒结构域的识别将为新的抗病毒药物策略提供靶点。

DESCRIPTION (provided by applicant): Despite decades of study, the immunobiology of paramyxoviruses such as RSV and parainfluenza remains poorly understood and a subject of intense controversy. This gap in knowledge has hampered the development of safe and effective vaccines and antiviral strategies. DCs are the most efficient antigen presenting cells (APCs) in inducing CTL responses to viruses. Interference with DC function, is a mechanism evolved by viruses to disrupt host defenses and survive immunological responses. The overall aim of this application is to define the in vitro interactions of human parainfluenza virus with dendritic cells (DCs). HPF3 infection can promote DC maturation while paradoxically interfering with their proper antigen presenting functions. Recent data suggest that the viral surface glycoproteins, the Hemagglutinin-Neuraminidase (HN) and the fusion protein (F), may mediate these effects. Our overall hypothesis is that interactions with DCs encountered shortly after infection of the respiratory mucosa are key determinants of HPF3 immunity and pathogenesis. Disruption of DC functions and impairment of cellular responses mediated by HN and F may contribute to the failure to establish long lasting protective immunity. Our first goal is to define the effects of the viral glycoproteins on differentiation and maturation of human DCs in vitro. We will dissect the specific contributions of HN and F and will determine whether particular functions of HN differentially affect this process. We will analyze how HPF3 infection -and exposure to the viral glycoproteins- influences migration and differentiation of monocytes into DCs in a tissue culture model of cell transmigration through endothelium. This model allows us to study how viral pathogens regulate DCs in a tissue setting, resembling more closely the natural conditions found in the mucosa of the human respiratory tract. Our second goal is to analyze HN and F immunoregulatory roles on the interaction of DCs with T cells in vitro. We will establish whether in vitro, HN and/or F account for the impairment of the stimulatory properties observed in HPF3 infected DCs by a direct cell contact-dependent mechanism. In addition, we will determine whether infection induces DCs to polarize T lymphocytes towards the expression of Th2 or Th1 type cytokines and whether HN and F are key determinants of this polarization. The definition of the viral glycoprotein(s) and their functions associated to the modulation of DCs will contribute to the ongoing effort for vaccine development through the generation of safer and more effective recombinant forms of HPF3. The identification of the viral domains important for HPF3-mediated immunoregulation will provide the target for novel antiviral pharmacologic strategies.