Study on cytomegalovirus: cell tropism, pathogenesis, and induction of protective antibodies.

与小鼠和大鼠巨细胞病毒不同，豚鼠巨细胞病毒(GPCMV)可通过胎盘引起宫内感染，这使得GPCMV动物模型可用于研究CMV经胎盘传播的机制。此前，我们报道了从ATCC购买的GPCMV包含两种类型的毒株，一种含有编码人CMV UL128和UL130同源物的1.6kb基因座，即GP129和GP131，而1.6kb基因座是病毒在动物中有效生长所必需的，但在细胞培养中不是必需的。HCMV UL128/130/131a与Gh/g1形成五聚体复合体，在内皮/上皮细胞趋化中发挥作用。在本研究中，我们构建了含有GPCMV基因组的BAC，该病毒在豚鼠成纤维细胞GPL中正常生长。使用针对BAC的REDET重组系统，将突变分别引入到GP129、GP131和GP133 ORF中。虽然所有突变体在GPL和GPC-16上的生长水平与来自具有野生型序列的BAC的病毒相似，但它们不能感染单核/巨噬细胞。通过共培养，GPCMV可从感染的巨噬细胞传给成纤维细胞。由于巨噬细胞在病毒向器官传播中起着重要作用，巨噬细胞的趋向性可能与病毒在体内的高效生长有关。

In contrast to murine and rat CMVs, guinea pig CMV (GPCMV) crosses the placenta and causes infection in utero, which makes GPCMV animal models useful for studies on the mechanisms of transplacental transmission of CMV. Previously, we reported that the GPCMV stock purchased from the ATCC contained two types of strains, one containing and the other lacking a 1.6 kb locus that encodes human CMV UL128 and UL130 homologs, GP129 and GP131, and that the 1.6 kb locus was required for efficient viral growth in animals but not in cell culture. HCMV UL128/130/131A form a pentamer complex with gH/gL and play a role in the endothelial/epithelial-tropism. In this study, we constructed a BAC containing a GPCMV genome, the virus from which grew normally in guinea pig fibroblast cells GPL. Using the RedET recombination system for BAC, mutations were introduced into each of GP129, GP131, and GP133 ORFs. Although all mutants grew in GPL and epithelial cell line GPC-16 at the level similar to a virus derived from the BAC with the wild-type sequence, they could not infect monocytes/ macrophages. GPCMV was transmittable to fibroblast from infected macrophages by co-culturing. Since macrophages play an important role in dissemination of virus to the organs, the macrophage tropism may associate with efficient viral growth in vivo.