Studies on Molecular Mechanisms of Host-Pathogen Interactions of Nidoviruses of Veterinary Importance

猪繁殖与呼吸综合征病毒（PRRSV）和猪流行性腹泻病毒（PEDV）造成了严重的农业经济损失，被认为是加拿大和世界范围内主要的新出现的牲畜病原体。两种病毒都是单链正义RNA包膜猪乳头状病毒，具有相似的颗粒结构、保守的基因组组织和复制策略等共同特征。传统的疫苗开发方法并没有产生可靠有效的疫苗，这些病毒仍然是全球养猪业的主要威胁。***我们认为，对尼多病毒与宿主相互作用的认识不足阻碍了针对尼多病毒的有效疫苗的开发。因此，我们建议研究动物尼多病毒与宿主相互作用的分子机制，以发现新的抗病毒靶点并制定有效的预防策略。该计划的长期目标是更好地了解动物尼多病毒与其宿主相互作用的分子机制，以便制定有效控制病毒感染的新策略。未来5年的短期目标是通过重点研究尼多病毒感染早期事件的表征和比较，阐明PRRSV和PEDV与宿主细胞的相互作用。为了实现这一目标，我们将：1)研究猪尼多病毒进入宿主细胞的细胞和分子机制；2)分析宿主细胞对病毒感染反应的蛋白质组学特征，表征尼多病毒的组成，并鉴定与病毒颗粒相关的宿主蛋白质。这些特定目标的实现将有助于了解尼多病毒感染早期病毒-宿主相互作用的本质。我们将鉴定与病毒基因组和蛋白质相互作用的细胞因子，以及与病毒颗粒结合并参与病毒感染调节的宿主蛋白。我们将绘制病毒蛋白高度保守和强效的抗原表位，这些抗原表位在病毒进入过程中短暂暴露，是疫苗设计的重要靶点。这些结果将为我们继续研究宿主细胞内病毒基因组和蛋白质的细胞内运输，病毒组装和释放的机制，以及尼多病毒利用和重新排列的细胞途径以促进感染和逃避宿主监视提供工具和方向。更重要的是，我们的发现将为抗病毒疫苗的开发提供新的特异性靶点。我们的发现也将与许多其他包膜动物病毒相关。* * * * * *

The porcine reproductive and*respiratory syndrome virus (PRRSV) and the porcine epidemic diarrhea virus*(PEDV) are responsible for severe agricultural economic losses and are*considered to be the primary emerging livestock pathogens in Canada and worldwide.*Both viruses are single-stranded, positive-sense RNA, enveloped porcine*nidoviruses and share common characteristics including similar particle*structure, conserved genomic organization and replication strategy. The*traditional approach to develop vaccines has not resulted in reliable and*effective vaccines, and these viruses remain a major threat to the swine*industry worldwide.***We believe that insufficient*understanding of nidovirus-host interactions hinders the development of*effective vaccines against nidoviruses. Therefore, we propose to investigate the molecular mechanisms of animal*nidovirus-host interactions in order to identify novel antiviral targets and*develop effective prevention strategies.***The*long-term goal of this program is to gain a better understanding of the molecular*mechanisms of interactions between animal nidoviruses and their hosts in order*to develop new strategies for effective control of viral infections. The short-term*goal for the next five years is to elucidate PRRSV and PEDV interactions with*host cells by focusing on the characterization and comparison of early events*in nidovirus infection. To address this objective, we will: 1) investigate the*cellular and molecular mechanisms underlying porcine nidovirus entry into host*cells, and 2) analyze proteomic profiles of host cell responses to viral*infection, characterize the composition of nidoviruses, and identify the host*proteins associated with the viral particle. The accomplishment of these*specific objectives will lead to an understanding of the nature of the*virus-host interaction during the earliest stage of nidovirus infection. We*will identify cellular factors interacting with the viral genome and proteins,*as well as host proteins that are incorporated into viral particles and*involved in modulation of viral infection. We will map the highly conserved and*potent antigenic epitopes of viral proteins, which are transiently exposed*during the process of virus entry and represent important targets for vaccine*design. These results will provide tools and directions for the continuation of*our research program in the investigation of intracellular trafficking of the viral*genome and proteins within the host cell, the mechanisms of viral assembly and*release, and the cellular pathways exploited and rearranged by nidoviruses to*facilitate infection and evade host surveillance. More importantly, our*findings will provide new specific targets for antiviral vaccine development. Our*findings will also be relevant to many other enveloped animal viruses. *** ***