Rossen J W, Strous G J, Horzinek M C, Rottier P J
Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.
J Gen Virol. 1997 Jan;78 ( Pt 1):61-9. doi: 10.1099/0022-1317-78-1-61.
Coronaviruses infect humans and animals through epithelial cells of the gastrointestinal and respiratory tracts that serve as their primary target. When studying infections in cultured polarized epithelial cells, we found previously that coronaviruses are released from specific plasma-membrane domains; thus, mouse hepatitis virus (strain A59; MHV-A59) leaves murine epithelial kidney cells from the basolateral surface, whereas release of transmissible gastroenteritis virus from porcine epithelial kidney cells is confined to the apical membrane. This observation begged the question whether a particular coronavirus is consistently shed through the same membrane, irrespective of the nature of the epithelial cell. We therefore extended our studies with MHV-A59 to Madin-Darby canine kidney (MDCK) strain I and human colon carcinoma (Caco-2) cells, both of which are naturally refractory to MHV-A59 but were made susceptible to infection by transfection with recombinant MHV receptor cDNA. The release of MHV-A59 from Caco(MHVR) cells occurred preferentially from the basolateral side, consistent with our previous observations. In contrast, release from MDCK(MHVR) cells occurred almost exclusively from the apical surface. Because of this difference, we studied MHV-A59 infection of MDCK(MHVR) cells in more detail. The virus entered the cells preferentially from the apical side, a situation similar to that in murine epithelial cells, where the highest density of MHV receptor glycoprotein was found. The results from this and previous studies show that targeting of vesicles containing MHV-A59 to a specific side of epithelial cells may vary in different epithelial cell types.
冠状病毒通过作为其主要靶标的胃肠道和呼吸道上皮细胞感染人类和动物。在研究培养的极化上皮细胞中的感染时，我们之前发现冠状病毒从特定的质膜结构域释放；因此，小鼠肝炎病毒（A59株；MHV - A59）从鼠肾上皮细胞的基底外侧表面离开，而传染性胃肠炎病毒从猪肾上皮细胞的释放局限于顶端膜。这一观察结果引发了一个问题，即特定的冠状病毒是否无论上皮细胞的性质如何，都始终通过同一膜释放。因此，我们将对MHV - A59的研究扩展到了麦迪逊 - 达比犬肾（MDCK）I株和人结肠癌细胞（Caco - 2），这两种细胞对MHV - A59天然具有抗性，但通过转染重组MHV受体cDNA使其易受感染。MHV - A59从Caco（MHVR）细胞的释放优先发生在基底外侧，这与我们之前的观察结果一致。相比之下，从MDCK（MHVR）细胞的释放几乎完全发生在顶端表面。由于这种差异，我们更详细地研究了MHV - A59对MDCK（MHVR）细胞的感染。病毒优先从顶端进入细胞，这种情况类似于在鼠上皮细胞中发现的情况，在鼠上皮细胞中发现了最高密度的MHV受体糖蛋白。这项研究和之前研究的结果表明，含有MHV - A59的囊泡靶向到上皮细胞特定一侧的情况在不同的上皮细胞类型中可能有所不同。
