Dye Charlotte, Temperton Nigel, Siddell Stuart G
Division of Virology, Department of Cellular and Molecular Medicine, School of Medical and Veterinary Sciences, University of Bristol, Bristol BS8 1TD, UK.
MRC/UCL Centre for Medical Molecular Virology, University College London, 46 Cleveland Street, London W1T 4JF, UK.
J Gen Virol. 2007 Jun;88(Pt 6):1753-1760. doi: 10.1099/vir.0.82666-0.
There are two types of feline coronaviruses that can be distinguished by serology and sequence analysis. Type I viruses, which are prevalent in the field but are difficult to isolate and propagate in cell culture, and type II viruses, which are less prevalent but replicate well in cell culture. An important determinant of coronavirus infection, in vivo and in cell culture, is the interaction of the virus surface glycoprotein with a cellular receptor. It is generally accepted that feline aminopeptidase N can act as a receptor for the attachment and entry of type II strains, and it has been proposed that the same molecule acts as a receptor for type I viruses. However, the experimental data are inconclusive. The aim of the studies reported here was to provide evidence for or against the involvement of feline aminopeptidase N as a receptor for type I feline coronaviruses. Our approach was to produce retroviral pseudotypes that bear the type I or type II feline coronavirus surface glycoprotein and to screen a range of feline cell lines for the expression of a functional receptor for attachment and entry. Our results show that type I feline coronavirus surface glycoprotein fails to recognize feline aminopeptidase N as a functional receptor on three continuous feline cell lines. This suggests that feline aminopeptidase N is not a receptor for type I feline coronaviruses. Our results also indicate that it should be possible to use retroviral pseudotypes to identify and characterize the cellular receptor for type I feline coronaviruses.
有两种猫冠状病毒，可通过血清学和序列分析加以区分。I型病毒在野外普遍存在，但难以在细胞培养中分离和繁殖；II型病毒则不太常见，但在细胞培养中复制良好。冠状病毒感染在体内和细胞培养中的一个重要决定因素是病毒表面糖蛋白与细胞受体的相互作用。一般认为，猫氨肽酶N可作为II型毒株附着和进入的受体，并且有人提出同一分子也作为I型病毒的受体。然而，实验数据尚无定论。本文报道的研究目的是为猫氨肽酶N是否作为I型猫冠状病毒的受体提供支持或反对的证据。我们的方法是产生携带I型或II型猫冠状病毒表面糖蛋白的逆转录病毒假型，并筛选一系列猫细胞系以寻找用于附着和进入的功能性受体的表达情况。我们的结果表明，I型猫冠状病毒表面糖蛋白无法将猫氨肽酶N识别为三种连续猫细胞系上的功能性受体。这表明猫氨肽酶N不是I型猫冠状病毒的受体。我们的结果还表明，利用逆转录病毒假型来鉴定和表征I型猫冠状病毒的细胞受体应该是可行的。
