Study for establishing differential diagnostic protocols for Japanese encephalitis virus and West Nile virus infection

本研究建立了黄病毒的鉴别诊断方法，特别是日本脑炎病毒（JEV）和西尼罗河病毒（WNV）的鉴别诊断方法。由于JEV与WNV同属黄病毒血清学群，在日本自然界中流行，且JEV与WNV感染后引起的症状相似，故应将两者区分开来，以确定WNV是否传入日本这个WNV未感染的国家。(1)我们建立了黄病毒反向遗传系统，生产亚病毒颗粒（SvPs），病毒复制子和病毒样颗粒（VLP）。SvP是指病毒包膜蛋白不含病毒相关RNA的颗粒结构。病毒复制子是RNA，其来源于病毒缺陷基因组RNA，并在复制子转染的细胞中自动复制。VLP是由病毒包膜蛋白作为其病毒外壳和外壳内的病毒复制子组成的颗粒。(2)利用JEV和WNV的SvPs建立了鉴别诊断方法，ELISA、IFA和Western blot分析用于鉴别JEV和WNV。(3)我们生成了表达报告蛋白的WNV应答。VLP组成。也产生了JEV或WNV结构蛋白作为表面包膜蛋白，以及壳内的WNV复制子。我们现在正在建立一个改进的中和试验鉴别诊断黄病毒使用的VLP。

In this research program, we established the differential diagnostic protocols for flaviviruses, especially Japanese encephalitis virus (JEV) and West Nile virus (WNV). Because, JEV, which belongs to the same flavivirus serological group, in which WNV belongs, circulates in the nature of Japan, and the symptoms caused by JEV and WNV infections are quite similar, we should differentiate both infections to confirm the impost of WNV into Japan where is a virgin country of WNV infection. (1) We established the flavivirus reverse genetic systems, to produce subviral particles (SvPs), viral replicons and virus-like particles (VLPs). SvPs are the particle structures composed by only viral envelope proteins without viral related RNAs. The viral replicons are the RNAs, which derived from viral defective genomic RNAs and auto-replicate in the replicon-transfected cells. The VLPs are the particles composed of viral envelope proteins as its viral shells, and viral replicons within the shells. (2) We established differential diagnostic protocols, ELISA, IFA and Western blot analysis to differentiate JEV and WNV using SvPs of JEV and WNV. (3) We generated reporter protein-expressing WNV replies. VLPs composed. of JEV or WNV structural proteins as surface envelope proteins, and WNV replicons within the shells, were also generated. We are now establishing a modified-neutralizing test for differential diagnosis of flaviviruses using the VLPs.