Tresnan D B, Holmes K V
Department of Microbiology, University of Colorado Health Sciences Center, Denver 80262, USA.
Adv Exp Med Biol. 1998;440:69-75. doi: 10.1007/978-1-4615-5331-1_9.
Human coronavirus HCV-229E and porcine transmissible gastroenteritis virus (TGEV), both members of coronavirus group I, use aminopeptidase N (APN) as their cellular receptors. These viruses show marked species specificity in receptor utilization as they can only use APN of their respective species to initiate virus infection. Feline and canine coronaviruses are also group I coronaviruses. To determine whether feline APN could serve as a receptor for feline coronaviruses (FCoVs), we cloned the cDNA encoding feline APN (fAPN) by PCR from feline cells and stably expressed it in FCoV-resistant mouse or hamster cells. These became susceptible to infection with either of several biotypes of FCoVs. The expression of recombinant fAPN also made hamster and mouse cells susceptible to infection with other group I coronaviruses, including several canine coronavirus strains, transmissible gastroenteritis virus (TGEV), and human coronavirus HCV-229E. Thus, fAPN served as a functional receptor for each of these coronaviruses in group I. As expected, fAPN could not serve as a receptor for mouse hepatitis virus (MHV), a group II coronavirus which uses murine biliary glycoproteins as receptors. Thus, fAPN acts as a common receptor for coronaviruses in group I, in marked contrast to human and porcine APN glycoproteins which serve as receptors only for human and porcine coronaviruses, respectively. These observations suggest that cats could serve as a "mixing vessel" in which simultaneous infection with several group I coronaviruses could lead to recombination of viral genomes.
人冠状病毒HCV - 229E和猪传染性胃肠炎病毒（TGEV）均为冠状病毒I群的成员，它们利用氨肽酶N（APN）作为细胞受体。这些病毒在受体利用上表现出明显的物种特异性，因为它们只能利用各自物种的APN来启动病毒感染。猫和犬冠状病毒也属于冠状病毒I群。为了确定猫APN是否可作为猫冠状病毒（FCoV）的受体，我们通过PCR从猫细胞中克隆了编码猫APN（fAPN）的cDNA，并在对FCoV具有抗性的小鼠或仓鼠细胞中稳定表达。这些细胞变得易受几种生物型FCoV中任何一种的感染。重组fAPN的表达也使仓鼠和小鼠细胞易受其他冠状病毒I群病毒的感染，包括几种犬冠状病毒株、传染性胃肠炎病毒（TGEV）和人冠状病毒HCV - 229E。因此，fAPN作为这些冠状病毒I群中每种病毒的功能性受体。正如预期的那样，fAPN不能作为小鼠肝炎病毒（MHV）的受体，MHV是一种冠状病毒II群病毒，它利用鼠胆汁糖蛋白作为受体。因此，fAPN作为冠状病毒I群的共同受体，这与分别仅作为人冠状病毒和猪冠状病毒受体的人APN和猪APN糖蛋白形成鲜明对比。这些观察结果表明，猫可能充当“混合容器”，在其中同时感染几种冠状病毒I群病毒可能导致病毒基因组的重组。
