Bioassay for human prions with the follicular dendritic cells

本研究的目的是利用滤泡树突状细胞(FDC)中异常的Prion蛋白(PrP^&lt；Sc&gt；)的积聚建立一种新的检测人类Prion感染的生物方法。今年，我分析了转基因小鼠和转基因小鼠体内PrP^&lt；SC&gt；在FDC中的积累。两种小鼠模型均表现出较短的潜伏期(~150天)，通过脑内接种来自散发性克雅氏病患者的人普恩病毒。转基因小鼠在FDC中有PrP^&lt；SC&gt；蓄积，而转基因小鼠则没有。这种现象是由于使用我们的转基因启动子使重组PrP在FDC中的表达减弱所致。利用转基因小鼠，在接种后30天内检测到PrP^&lt；SC&gt；积累。在稀释系列中，FDC生物检测系统需要75天，具有足够的灵敏度(在10-7稀释人Pron中有50%阳性)，与以前需要2年孵育的脑内接种生物检测相比。因此，FDC法是一种快速、灵敏的检测普恩病毒感染的生物检测方法。该系统还可用于分析英国变种CJD(VCJD)的人普恩病毒。所有基因敲除小鼠在接种75天后均出现vCJD蛋白阳性FDC染色。

The purpose of this study is to establish a new bioassay for human prion infection using abnormal prion protein (PrP^<Sc>) accumulations in the follicular dendritic cells (FDC). This year, I analyzed PrP^<Sc> accumulations in FDC both in the transgenic mouse and the knock-in mouse. The both mouse models demonstrated a short incubation periond (〜150 days) by the intracerebral inoculation of human prions from a patient with sporadic Creutzfeldt-Jakob disease. The knock-in mouse had PrP^<Sc> accumulations in the FDC, but the transgenic mouse did not. This phenomenon is due to an attenuated expression of the recombinant PrP in the FDC using our transgenic promoter. With the knock-in mouse, PrP^<Sc> accumulations were detected within 30 days post-inoculation. With dilution series, FDC bioassay system, which takes 75 days, showed enough sensitivity (50% positive in 10-7 diluted human prions) to compare the previous intracerebral inoculation bioassay, which takes 2 years incubation. Therefore, FDC assay provides a rapid and sensitive bioassay for human prion infections. This system is also available to assay human prions of variant CJD (vCJD) in United Kingdom. All the knock-in mice showed the positive FDC stainings with vCJD prions inoculations after 75 post -inoculation.