PDF(Pubmed)
Abstract：
Several cellular factors have been reported to be required for replication of classical swine fever virus (CSFV), a member of the genus Pestivirus within the family Flaviviridae. However, many steps of its replication cycle are still poorly understood. The low-density lipoprotein receptor (LDLR) is involved in cell entry and post-entry processes of different viruses including other members of the Flaviviridae. In this study, the relevance of LDLR in replication of CSFV and another porcine pestivirus, Bungowannah pestivirus (BuPV), was investigated by antibody-mediated blocking of LDLR and genetically engineered porcine cell lines providing altered LDLR expression levels. An LDLR-specific antibody largely blocked infection with CSFV, but had only a minor impact on BuPV. Infections of the genetically modified cells confirmed an LDLR-dependent replication of CSFV. Compared to wild type cells, lower and higher expression of LDLR resulted in a 3.5-fold decrease or increase in viral titers already 20 h post infection. Viral titers were 25-fold increased in LDLR-overexpressing cells compared to cells with reduced LDLR expression at 72 h post infection. The varying LDLR expression levels had no clear effect on permissivity to BuPV. A decoy receptor assay using recombinant soluble LDLR provided no evidence that LDLR may function as a receptor for CSFV or BuPV. Differences in their dependency on LDLR suggest that CSFV and BuPV likely use different mechanisms to interact with their host cells. Moreover, this study reveals similarities in the replication cycles of CSFV and other members of the family Flaviviridae that are dependent on LDLR.
摘要：
据报道，经典猪瘟病毒（CSFV）的复制需要几种细胞因子，黄病毒科瘟病毒属的成员。然而,其复制周期的许多步骤仍然知之甚少。低密度脂蛋白受体（LDLR）参与包括黄病毒科其他成员在内的不同病毒的细胞进入和进入后过程。在这项研究中,LDLR在CSFV和另一种猪瘟病毒复制中的相关性，Bungowannah瘟病毒（BuPV），通过抗体介导的LDLR阻断和提供改变的LDLR表达水平的基因工程猪细胞系进行研究。LDLR特异性抗体在很大程度上阻断了CSFV的感染，但对BuPV的影响很小。遗传修饰的细胞的感染证实了CSFV的LDLR依赖性复制。与野生型细胞相比，LDLR的较低和较高表达导致感染后20小时病毒滴度降低或增加3.5倍。与感染后72小时LDLR表达降低的细胞相比，LDLR过表达细胞中的病毒滴度增加了25倍。不同的LDLR表达水平对BuPV的通透性没有明显影响。使用重组可溶性LDLR的诱饵受体测定没有证据表明LDLR可以作为CSFV或BuPV的受体起作用。它们对LDLR依赖性的差异表明CSFV和BuPV可能使用不同的机制与其宿主细胞相互作用。此外，这项研究揭示了CSFV和依赖LDLR的黄病毒科其他成员的复制周期的相似性。
