Molecular Biological Studies on Demyelination Induced by Theiler's Virus Tohoku University School of Medicine

泰勒病毒（Theller's virus，TV）分为两个亚群。GDVII亚群菌株引起小鼠脊髓中的急性脊髓灰质炎，而DA亚群菌株引起持续性脱髓鞘疾病，尽管血清和CSF中存在针对TV的高抗体滴度。作为一个可能的机制，区分两个亚组的脱髓鞘活性，不同的嗜细胞性少突胶质细胞（OL）已被提出。本项目的主要目的是通过使用来自那些亚群毒株的重组病毒和通过使用OL.AL的原代培养物来阐明这一点。首先，我们从已经报道的三个重叠克隆中产生了DA毒株的全长cDNA（Virology 164：245-255，1988）。来自转录本转染的病毒产生与野生型病毒无区别的脱髓鞘疾病。感染性克隆为株间重组病毒的生产提供了关键试剂，以帮助鉴定与OL和脱髓鞘的亲细胞性相关的遗传位点。e.将DA和GDVII接种于C_3H小鼠来源的OL原代培养物中，研究其感染和增殖。使用抗半乳糖苷和抗TV抗体的双重染色显示两种菌株感染OL。此外，无细胞和细胞相关感染性的动力学在两种菌株之间没有显著差异。这些体外观察结果表明，复制或细胞相关感染性都不是区分这两个亚群菌株的唯一因素。

Theller's virus (TV) is divided into two subgroups. GDVII subgroups strains cause acute polloencephalomyelitis in the spinal cords of mice, whereas DA subgroup strains cause a persistent demyelinating disease in spite of the presence of high antibody titers against TV in the sera and CSF. As a possible mechanism to discriminate two subgroups with regard to the demyelinating activity, different cytotropism to oligodendrocytes (OL) has been proposed. The major goal of this project is to clarify this point by using recombinant virus from those subgroup strains and by using primary culture of OL.AL first, we generated a full-length cDNA of DA strain from three overlapping clones which had been already reported (Virology 164 : 245-255, 1988). Virus derived from transfection of transcripts produced a demyelinating disease indistinguishable from that of wild-type virus. The infectious clone provides a critical reagent for the production of interstrain recombinant viruses to help indentify genetic loci responsible for the cytotropism in OL and demyelination as well.On the other hand, two strains, i. e. DA and GDVII, were inoculated into the primary culture of OL derived from C3H mice and the infection and the propagation were studied. Double staining using anti-galactocerebroside and anti-TV antibodies revealed both strains infected OL. In addition, the kinetics of cell-free and cell-associated infectivity were not significantly different between two strains. These in vitro observation suggests that neither replication nor cell-associated infectivity is a sole factor in discriminating those two subgroup strains.