中国流行性乙型脑炎病毒表型和基因型的研究进展

Progress in the Research of Phenotype and Genotype of Japanese Encephalitis Virus in China

流行性乙型脑炎(乙脑)病毒是引起病毒性脑炎最主要的病毒之一,本文对我国分离株的表型和基因型特性进行了综合分析。生物学特征研究显示,不同毒株间存在空斑形态、小鼠神经侵入致病性、保护性抗原和血凝性的明显差异。中国在1977年前,自然界中仅存在基因Ⅲ型乙脑病毒,但自1977年以后基因Ⅰ型和Ⅲ型病毒均从自然界分离到,而基因Ⅰ型病毒已成为优势病毒,其中多数分离自蚊虫。基因序列分析显示,两种基因型的氨基酸序列差异率很小(≤3%),与当前广泛应用的减毒活疫苗株比较,仅≤3%的氨基酸序列差异率,这些差别主要存在于与SA14-14-2减毒相关的位点,提示SA14-14-2疫苗能够有效地保护这两种基因型毒株的感染。

Japanese encephalitis virus（JEV）is one of the leading cause of viral encephalitis in Asia. The phenotypic and genotypic characteristics of isolated virus strains are reviewed in this paper. Studies on the biological characteristics of the isolates showed that different isolates existed apparent differences in virus plaque morphology, neuroinvasive pathogenicity in mice, protective antigenicity and hemagglutination property. In China, only genotype III JEV strains were isolated before 1977. But since 1977, both genotype I and III JEV strains were isolated and the genotype I virus, which was isolated from mosquitoes mostly, has become the dominant strain. Study on the genomic sequence indicated that there was only a few amino acid difference （≤3%） between the two genotype isolates. Comparison between both genotype isolates and widely used live vaccine strain SA14-14-2 revealed that there were only ≤3% amino acid differences, most of whic SA14-14-2 live vaccine is h were the SA14-14-2 unique attenuating sites. These results indicate that the able to protect people against infection of the both genotype I and III JEV strains.