CD21-dependent infection of an epithelial cell line, 293, by Epstein-Barr virus
CD21-dependent infection of an epithelial cell line, 293, by Epstein-Barr virus
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DOI：
10.1128/jvi.73.3.2115-2125.1999
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发表时间：
1999-03-01
影响因子：
5.4
通讯作者：
Yates, JL
中科院分区：
文献类型：
--
作者：
Fingeroth, JD;Diamond, ME;Yates, JL
EB病毒(Epstein-Barr Virus，EBV)在未分化的鼻咽癌中普遍存在，在其他肿瘤中也有零星存在，在口腔毛状白斑病变的舌上皮分化层中也有复制。然而，目前尚不清楚EBV感染上皮细胞的频率有多高，或通过何种机制正常感染。在这里，我们报告了一个人上皮细胞系293，可以稳定地感染EBV，这种病毒已经被基因标记为可选择的基因。我们发现293细胞表达相对较低水平的CD21，可以检测到荧光素标记的EBV与293细胞的结合，并且针对CD21的抗体可以阻断病毒与细胞的结合和感染。已知与淋巴细胞表面CD21形成复合物的两种蛋白质CD35和CD19在293细胞表面未检测到。293细胞的所有感染克隆都表现出与II型潜伏期相似的基因表达模式，但强制表达裂解反式激活因子R和Z可以有效地诱导感染性病毒的有效复制和释放。检测到低水平的EBV转化膜蛋白LMP-1和LMP-2，但LMP-1蛋白要么无法检测到，要么接近EBV转化B细胞典型水平的5%。在两个EBV感染的293细胞克隆的细胞表面，检测到LMP-1可诱导上皮细胞的表皮生长因子受体表达略有增加。这些结果表明，低水平的表面CD21可以支持EBV感染上皮细胞系。这些结果还提出了一种可能性，即在EBV对上皮细胞的正常感染中，LMP-1蛋白的表达水平没有高到足以致癌，并且EBV相关的上皮性癌症细胞中可能存在差异，从而允许LMP-1的表达增加。
Epstein-Barr virus (EBV) is invariably present in undifferentiated nasopharyngeal carcinomas, is found sporadically in other carcinomas, and replicates in the differentiated layer of the tongue epithelium in lesions of oral hairy leukoplakia. However, it is not clear how frequently or by what mechanism EBV infects epithelial cells normally. Here, we report that a human epithelial cell line, 293, can be stably infected by EBV that has been genetically marked with a selectable gene. We show that 293 cells express a relatively low level of CD21, that binding of fluorescein-labeled EBV to 293 cells can be detected, and that both the binding of virus to cells and infection can be blocked with antibodies specific for CD21. Two proteins known to form complexes with CD21 on the surface of lymphoid cells, CD35 and CD19, could not be detected at the surface of 293 cells. All infected clones of 293 cells exhibited tight latency with a pattern of gene expression similar to that of type II latency, but productive EBV replication and release of infectious virus could be induced inefficiently by forced expression of the lytic transactivators, R and Z. Low levels of mRNA specific for the transforming membrane protein of EBV, LMP-1, as well as for LMP-2, were detected; however, LMP-1 protein was either undetectable or near the limit of detection at less than 5% of the level typical of EBV-transformed B cells. A slight increase in expression of the receptor for epidermal growth factor, which can be induced in epithelial cells by LMP-1, was detected at the cell surface with two EBV-infected 293 cell clones. These results show that low levels of surface CD21 can support infection of an epithelial cell line by EBV. The results also raise the possibility that in a normal infection of epithelial cells by EBV, the LMP-1 protein is not expressed at levels that are high enough to be oncogenic and that there might be differences in the cells of EBV-associated epithelial cancers that have arisen to allow for elevated expression of LMP-1.