我国新分离乙型脑炎病毒株毒力特征研究

将分离自不同年代的17株乙脑毒株在小鼠脑内传代,然后将病毒在BHK21细胞单层上观察不同毒株的空斑形成大小形态,小鼠脑内和皮下途径接种观察病毒的毒力,结果显示不同毒株在BHK21细胞上形成的噬斑大小不尽相同,减毒株形成的噬斑最小。所有毒株对小鼠的脑内毒力都很强,病毒滴度高达lg8.0/mL以上,毒株间无明显差异。毒株对9～11g小日龄小鼠的皮下毒力有一定差异但不明显,但对14～16g较大日龄小鼠则差别明显。PFU/LD50的对数值差异除一株(M47株)为8.44外,其余各株差别在3.94～0.45间。本研究结果证明自然界乙脑毒株存在明显的神经外毒力差异,毒力差异与分离年代和病毒基因型无关,但从人体分离到的毒株毒力表现较强。

Study on the Phenotypic Characteristics of Japanese Encephalitis Virus Strains Isolated from Different Years

In order to reveal the phenotypic characteristics of 17 JE virus strains isolated from different years,plaque sizes,mice neurovirulence and mice neuroinvasiveness of the isolates were studied and compared.BHK21 cell monolayers were used for testing the plaque sizes.The virus neurovirulence was tested in 9-11g mice inoculated intracerebrally and the virus neuroinvasiveness was tested in 9-11g and 14-16g by subcutaneous inoculation.Results showed that all the viruses produced clear plaques on the BHK21 cell monolayers with different sizes and all the virus strains appeared high neurovirulence in the mice with higher than lg8.0/0.03mL virus titers,while no apparent difference among them.The neuroinvasiveness(subcutaneous virulence) tested in the 9-11g mice had shown a little difference,but when tested in the 12-14 g mice,the difference was apparent.The results demonstrated that JEV in nature were highly neurovirulent with no apparent difference.However the neuroinvasiveness of the JEV in nature was greatly different,which didn't relate to the years of isolation and genotypes,but most of the viruses isolated from patients showed higher neuroinvasiveness.