MacCormac L P, Grundy J E
Department of Clinical Immunology, Royal Free Hospital School of Medicine, London, England.
J Med Virol. 1999 Mar;57(3):298-307. doi: 10.1002/(sici)1096-9071(199903)57:3<298::aid-jmv14>3.0.co;2-p.
The highly fibroblast-passaged AD169, Towne, and Davis strains of cytomegalovirus (CMV) were found to have a restricted capacity to infect endothelial cells in vitro. Although such replication could be increased by a combination of low speed centrifugation and sodium butyrate treatment, the extracellular virus produced was infectious for fibroblasts but not for endothelial cells. In contrast, the low passage Toledo strain, and a low passage fibroblast-grown clinical isolate of CMV, C1F, could be continually passaged in endothelial cells, giving the strains C1FE and Toledo.E. Whilst, using the conditions described above, initial infection of endothelial cells with AD169 or C1F resulted in similar titres of extracellular virus as assayed on fibroblasts, only the virus from the C1F strain was infectious for endothelial cells. Passage of C1F in fibroblasts decreased its ability to infect endothelial cells, whilst retaining equal ability to infect fibroblasts. Although endothelial-cell-passaged cell-free C1FE virus was endothelial cell-tropic, it was still much more infectious for fibroblasts than for endothelial cells. It is concluded that the C1F and Toledo strains, but not the AD169, Towne, or Davis strains, contained endothelial cell tropic variants, which could be lost on passage through fibroblasts, but retained on passage through endothelial cells. Furthermore, virus in an ex vivo source of CMV, a blood specimen, was found to be more tropic for fibroblasts than for endothelial cells, suggesting that in vivo CMV exists as quasi strains with different cell tropism, some of which might be lost in vitro by passage in an inappropriate cell type.
巨细胞病毒（CMV）的高传代成纤维细胞株AD169、Towne和Davis株在体外感染内皮细胞的能力有限。虽然低速离心和丁酸钠处理相结合可增加这种复制，但产生的细胞外病毒对成纤维细胞有感染性，而对内皮细胞无感染性。相比之下，低传代的托莱多株以及低传代的成纤维细胞生长的CMV临床分离株C1F能够在内皮细胞中连续传代，分别得到C1FE株和托莱多E株。虽然使用上述条件，用AD169或C1F初始感染内皮细胞后，在成纤维细胞上检测到的细胞外病毒滴度相似，但只有C1F株产生的病毒对内皮细胞有感染性。C1F在成纤维细胞中传代会降低其感染内皮细胞的能力，而感染成纤维细胞的能力保持不变。虽然内皮细胞传代的无细胞C1FE病毒具有内皮细胞嗜性，但它对成纤维细胞的感染性仍远高于对内皮细胞的感染性。结论是，C1F和托莱多株而非AD169、Towne或Davis株含有内皮细胞嗜性变体，这些变体在通过成纤维细胞传代时可能丢失，但在通过内皮细胞传代时得以保留。此外，在CMV的一种体外来源即血液标本中发现，病毒对成纤维细胞的嗜性高于对内皮细胞的嗜性，这表明体内CMV以具有不同细胞嗜性的准种形式存在，其中一些在体外通过在不适当的细胞类型中传代可能会丢失。
