Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA.
Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
J Virol. 2019 Jan 4;93(2). doi: 10.1128/JVI.01849-18. Print 2019 Jan 15.
The alphaherpesvirus pseudorabies virus (PRV) is the causative agent of pseudorabies, a disease of great economic and welfare importance in swine. Other alphaherpesviruses, including herpes simplex virus (HSV), utilize low-pH-mediated endocytosis to enter a subset of cell types. We investigated whether PRV used this entry pathway in multiple laboratory model cell lines. Inhibition of receptor-mediated endocytosis by treatment with hypertonic medium prevented PRV entry. PRV entry into several cell lines, including porcine kidney (PK15) cells and African green monkey kidney (Vero) cells, was inhibited by noncytotoxic concentrations of the lysosomotropic agents ammonium chloride and monensin, which block the acidification of endosomes. Inactivation of virions by acid pretreatment is a hallmark of viruses that utilize a low-pH-mediated entry pathway. Exposure of PRV virions to pH 5.0 in the absence of host cell membranes reduced entry into PK15 and Vero cells by >80%. Together, these findings suggest that endocytosis followed by fusion with host membranes triggered by low endosomal pH is an important route of entry for PRV. PRV is a pathogen of great economic and animal welfare importance in many parts of the world. PRV causes neurological, respiratory, and reproductive disorders, often resulting in mortality of young and immunocompromised animals. Mortality, decreased production, and trade restrictions result in significant financial losses for the agricultural industry. Understanding the molecular mechanisms utilized by PRV to enter host cells is an important step in identifying novel strategies to prevent infection and spread. A thorough understanding of these mechanisms will contribute to a broader understanding of alphaherpesvirus entry. Here, we demonstrate PRV entry into multiple model cell lines via a low-pH endocytosis pathway. Together, these results provide a framework for elucidating the early events of the PRV replicative cycle.
α疱疹病毒伪狂犬病病毒（PRV）是伪狂犬病的病原体，伪狂犬病是一种对猪具有重要经济和福利意义的疾病。其他α疱疹病毒，包括单纯疱疹病毒（HSV），利用低 pH 值介导的内吞作用进入一组细胞类型。我们研究了 PRV 是否在多种实验室模型细胞系中使用这种进入途径。用高渗培养基处理抑制受体介导的内吞作用可防止 PRV 进入。PRV 进入包括猪肾（PK15）细胞和非洲绿猴肾（Vero）细胞在内的几种细胞系的进入被非细胞毒性浓度的溶酶体趋化剂氯化铵和莫能菌素抑制，这两种药物阻断内体的酸化。病毒粒子通过酸预处理失活是利用低 pH 值介导的进入途径的病毒的标志。在没有宿主细胞膜的情况下，将 PRV 病毒暴露于 pH 5.0 下可使 PK15 和 Vero 细胞中的进入减少 >80%。这些发现表明，内吞作用后，低内体 pH 触发的与宿主膜融合是 PRV 进入的重要途径。PRV 是世界许多地区具有重要经济和动物福利意义的病原体。PRV 引起神经、呼吸和生殖障碍，常导致幼龄和免疫功能低下动物死亡。死亡率、产量下降和贸易限制给农业产业带来重大经济损失。了解 PRV 进入宿主细胞所利用的分子机制是确定预防感染和传播的新策略的重要步骤。对这些机制的全面了解将有助于更广泛地了解α疱疹病毒的进入。在这里，我们证明 PRV 通过低 pH 值内吞作用途径进入多种模型细胞系。这些结果为阐明 PRV 复制周期的早期事件提供了框架。
