西尼罗病毒与乙型脑炎病毒生物学性状的比较与鉴别

Comparison and discrimination of the biological characteristics between West Nile virus and Japanese encephalitis virus

目的对西尼罗病毒(WNV)和乙脑病毒(JEV)的致细胞病变效应(CPE)、致病性、形态学、免疫学和分子生物学性状进行比较,为WNV感染的鉴别诊断提供依据。方法通过给C6/36细胞和乳鼠接种WNV或JEV,观察两种病毒的CPE和致病性;制作组织切片的透射电镜标本进行病毒形态学观察;分别用间接免疫荧光试验(IFA)和RTPCR方法对两种病毒抗体阳性血清及病毒核酸进行检测。结果WNV和JEV所致C6/36细胞CPE分别以细胞融合和细胞脱落为主要特征;脑内接种两种病毒对乳鼠的致病性未见明显差别;电镜下,两种病毒体的形态与大小相似;WNV与JEV之间存在抗原交叉反应;用黄病毒通用引物可从WNV和JEV感染组织中检出病毒核酸,而用特异引物仅能扩增出相应病毒的核苷酸片段。结论病毒所致C6/36细胞CPE与病毒核酸检测可作为WNV与JEV有效的鉴别方法,对两种病毒抗体效价进行同时测定有助于病原体感染的诊断。

Objective To compare the biological characteristics of West Nile virus （WNV） and Japanese encephalitis virus （JEV）, including cells sensitivity, pathogenicity, viral morphology, as well as the results of immunological and molecular biological detection. Methods Cytopathic effect （ CPE ） and pathogenicity were observed in C6/36 cells and in suckling mice inoculated intraeerebrally with the WNV or JEV, respectively. The sliced tissue samples for electron microscopic examination were prepared for the morphologic observation of the viruses. Serum antibody to WNV or JEV was detected using indirect immunofluorescence assay （IFA） , and the viral RNA was analyzed by RT-PCR method. Results WNV or JEV-caused CPE was characterized by cell fusion and cell shedding, respectively. There was no significant difference in the pathogenicity to suckling mice between WNV and JEV. The morphologic observation showed that the shape and size of the two virions were similar. WNV and JEV were found to have antigenic crossreactivity. The viral RNA could be detected from both WNV and JEV samples with universal primer set, but only nucleoside fragments of corresponding virus could be amplified when specific primers were used. Conclusion CPE in C6/36 cell and detection of the viral RNA should be useful in discrimination of WNV and JEV, and simultaneously examining the titers of serum antibodies against WNV and JEV may be helpful to diagnosis of infection with these agents.