Transmission Experiment with transgenic model

为了建立灵敏的人朊病毒生物检测系统，我们建立了人-鼠嵌合朊蛋白转基因小鼠。我们获得了3个密码子为129 Met的朊蛋白转基因系和2个密码子为129 Val的朊蛋白转基因系，与野生型小鼠相比，转基因系的重组朊蛋白表达量从0.6倍到18倍不等。对散发性克雅氏病（CJD）患者脑组织进行脑内接种后，低表达系（0.6或1.2倍）潜伏期最短（约150天）（野生型：密码子129 Met/Met，密码子219 Glu/Glu），中表达系（2或4倍）潜伏期较长。高表达系（9次或18次）表现出高表达综合征，潜伏期较长，不适合进行传播实验。接下来，我们在散发型CJD（密码子129 Val/Met基因型）和硬脑膜相关性CJD（密码子129 Met/Met基因型）患者中进行了传播实验。在这些传播研究中，我们认识到一种特殊类型的硬脑膜相关CJD即使在孵化360天后也没有成功传播。因此，不仅通过临床病理变化，而且通过传播实验，我们在英国的新型CJD患者中发现了一种独特类型的硬脑膜相关CJD，具有许多华丽斑块。

To make a sensitive bioassay system for human prions, we established the transgenic mice with human/mouse chimeric prion protein. We have 3 transgenic lines with codon 129 Met prion protein, and 2 lines with codon 129 Val. Transgenic lines showed various expression level of recombinant prion protein from 0.6 times to 18 times, comparing with the expression of wild-type mouse. The low expression lines (0.6 or 1.2 times) with ablated background showed the shortest incubation period (approximately 150 days) after the intracerebral inoculation of the brain tissues from a patient with sporadic Creutzfeldt-Jakob disease (CJD) (wild type : codon 129 Met/Met, codon 219 Glu/Glu), and the medium expression lines (2 or 4 times) showed the long incubation period. The high expression lines (9 or 18 times) were seen to be inadequate for the transmission experiment because of showing the high expression syndrome and longer incubation periods. Next, we did the transmission experiment form patients with sporadic CJD (codon 129 Val/Met genotype), dura-associated CJD (codon 129 Met/Met genotype). Among these transmission studies, we recognized that a special type of dura-associated CJD showed unsuccessful transmission even after 360 days' incubation. Therefore, not only with the clinicopathological changes, but also with the transmission experiment, we identified a distinct type of dura-associated CJD with many florid plaques as seen in patients with new variant CJD in United Kingdom.