Transmission Experiment with transgenic model

为了建立灵敏的人蛋白生物检测系统，我们建立了人/鼠嵌合蛋白转基因小鼠。共获得3株密码子为129的蛋氨酸蛋白转基因株和2株密码子为129 Val的转基因株系。与野生型小鼠相比，转基因小鼠的重组PrP蛋白表达水平从0.6倍到18倍不等。1例散发性克雅病(CJD)(野生型：密码子129 Met/Met，密码子219 Glu/Glu)脑内接种后，低表达株(0.6倍或1.2倍)潜伏期最短(约150天)，中等表达株(2倍或4倍)潜伏期最长。高表达株系(9倍或18倍)表现出高表达综合征和较长的潜伏期，不适合进行传播实验。接下来，我们进行了散发性CJD患者(密码子129 Val/Met)和硬脑膜相关性CJD患者(密码子129 Met/Met)的传播实验。在这些传播研究中，我们认识到一种特殊类型的与硬脑膜相关的CJD即使在孵化360天后也显示出不成功的传播。因此，不仅结合临床病理改变，而且结合传递实验，我们发现了一种独特的硬脑膜相关CJD类型，并有许多鲜艳的斑块，如英国新变异型CJD患者所见。

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.