Impact of envelope proteins on poxviral pathogenesis

 描述(申请人提供)：痘病毒是双链DNA病毒，其蛋白质核心被脂膜包裹。脂质包膜中嵌入了四种保守的病毒蛋白，它们被认为是介导病毒结合的媒介。虽然这些蛋白的功能已经在体外进行了研究，但它们在体内对痘病毒趋向性和致病机制的影响仍不清楚。我们现在提供的数据表明，从麻痘病毒粘液瘤中移除其中一种包膜蛋白，假定的软骨素结合蛋白M083L，通过限制病毒的全身传播，显著地减轻了进化上相关宿主物种的病毒致病。关键的是，M083的缺失严重限制了粘液瘤病毒对激活的T细胞的趋向性，为该蛋白影响病毒传播提供了直接机制。然而，其余三种痘病毒包膜蛋白的作用尚不清楚。因此，我们提出了目前的建议，旨在通过以下方式确定每个保守的痘病毒包膜蛋白如何影响病毒嗜性和疾病发病机制：从MYXV基因组中移除每个病毒包膜蛋白(特定目标1)，表征这些包膜蛋白的移除如何影响病毒在体外的复制(特定目标2)，以及确定每个病毒包膜蛋白的移除如何影响病毒的嗜性和体内的致病作用(特定目标3)。我们预计，拟议的研究将揭示每个单独的痘病毒包膜蛋白如何影响病毒在体内的致病机制和趋向性。这些研究不仅将促进我们对痘病毒生物学的基本了解，而且还将通过允许痘病毒疫苗接种策略的基本设计和通过增加我们对如何改变体内病毒的趋向性以增加病毒传播和向残留疾病部位的传递来改进基于痘病毒的溶瘤作用来显著影响公众健康。

 DESCRIPTION (provided by applicant): Poxviruses are double-stranded DNA viruses whose protein core is surrounded by a lipid envelope. Embedded into the lipid envelope are four conserved viral proteins which are thought to mediate viral binding. While the function of these proteins has been studied in vitro, their impact on poxviral tropism and pathogenesis in vivo remains unknown. We now present data demonstrating that removal of one of these envelope proteins, the putative chondroitin binding protein M083L, from the leporipoxvirus myxoma significantly attenuates viral pathogenesis in an evolutionarily relevant host species by limiting systemic viral dissemination. Critically, loss of M083 severely restricts myxoma virus tropism for activated T cells providing a direct mechanism through which this protein impacts viral dissemination. The roles of the remaining three poxviral envelope proteins, however, remains unknown. We therefore put forth the current proposal designed to identify how each of the conserved poxviral envelope proteins impacts viral tropism and disease pathogenesis by: removing each viral envelope protein from the genome of MYXV (Specific Aim 1), characterizing how removal of these envelope proteins impacts viral replication in vitro (Specific Aim 2), and identifying how removal of each viral envelope protein impacts viral tropism and pathogenesis in vivo (Specific Aim 3). We anticipate that the proposed studies will uncover how each individual poxviral envelope protein impacts viral pathogenesis and tropism in vivo. These studies will not only advance our understanding of basic poxviral biology but will also significantly impact public health both by allowing for rationale design of poxviral vaccination strategies and improving poxvirus-based oncolytics by increasing our understanding of how to alter viral tropism in vivo to increase viral dissemination and delivery to sites of residual disease.