Clayson E T, Compans R W
Department of Microbiology, University of Alabama, Birmingham 35294.
Mol Cell Biol. 1988 Aug;8(8):3391-6. doi: 10.1128/mcb.8.8.3391-3396.1988.
The uptake of simian virus 40 (SV40) by polarized epithelial cells was investigated by growth of cells on permeable supports and inoculation on either the apical or the basolateral surface. Binding of radiolabeled SV40 occurred on the apical but not the basolateral surfaces of permissive polarized Vero C1008 cells and nonpermissive polarized MDCK cells. When similar experiments were performed on nonpolarized Vero or CV-1 cells, virus binding occurred regardless of the direction of virus input. Electron micrographs of Vero C1008 cells infected at high multiplicities revealed virions lining the surfaces of apically infected cells, while the surfaces of basolaterally infected cells were devoid of virus particles. Analysis of the binding data revealed a single class of virus receptors (9 x 10(4) per cell) with a high affinity for SV40 (Kd = 3.76 pM) on the apical surfaces of Vero C 1008 cells. Indirect immunofluorescence studies revealed that synthesis of viral capsid proteins in Vero C1008 cells occurred only when input virions had access to the apical surface. Virus yields from apically infected Vero C1008 cells were 10(5) PFU per cell, while yields obtained from basolaterally infected cells were less than one PFU per cell. These results indicate that a specific receptor for SV40 is expressed exclusively on the apical surfaces of polarized Vero C1008 cells.
通过将细胞接种在可渗透支持物上并在顶侧或基底外侧表面接种，研究了极化上皮细胞对猿猴病毒40（SV40）的摄取。放射性标记的SV40在允许性极化的Vero C1008细胞和非允许性极化的MDCK细胞的顶侧表面而非基底外侧表面发生结合。当在非极化的Vero或CV-1细胞上进行类似实验时，无论病毒输入方向如何，都会发生病毒结合。高倍感染的Vero C1008细胞的电子显微镜照片显示，顶侧感染细胞的表面排列着病毒粒子，而基底外侧感染细胞的表面没有病毒颗粒。结合数据分析显示，Vero C1008细胞顶侧表面存在一类对SV40具有高亲和力（Kd = 3.76 pM）的病毒受体（每个细胞9×10⁴个）。间接免疫荧光研究表明，只有当输入的病毒粒子能够接触到顶侧表面时，Vero C1008细胞中才会发生病毒衣壳蛋白的合成。顶侧感染的Vero C1008细胞的病毒产量为每个细胞10⁵ PFU，而基底外侧感染细胞的产量则低于每个细胞1 PFU。这些结果表明，SV40的特异性受体仅在极化的Vero C1008细胞的顶侧表面表达。
