流行性乙型脑炎病毒减毒株SA14-14-2E基因稳定性研究

The stability of E gene of the Japanese encephalitis attenuated virus strain SA14-14-2

为研究乙脑病毒减毒株SA14-14-2 E蛋白基因稳定性,将乙脑病毒减毒株SA14-14-2在原代地鼠肾细胞(PHK)上传至18代,应用RT-PCR分别扩增PHK6代、PHK7代、PHK8代、PHK13代、PHK18代E蛋白基因并测序后,与Genebank中乙脑病毒减毒株SA14-14-2(D90195)进行比较分析。PHK6、PHK7、PHK8代病毒与D90195 E蛋白核苷酸和氨基酸序列完全相同。PHK13、PHK18代病毒与D90195E蛋白核苷酸序列同源性分别为99.8%、99.7%,与D90195E蛋白氨基酸序列同源性分别为99.6%、99.4%。各代次病毒E蛋白与减毒相关氨基酸未发生改变,同时所有突变的氨基酸均非SA14原有的,故不是恢复性突变。结果表明乙脑病毒减毒株SA14-14-2的遗传学特性稳定,从分子水平证明乙脑病毒减毒株SA14-14-2及其生产的疫苗具有安全性。

In order to study the genetic stability of E gcne region of Japanese encephalitis attenuated virus strain SA14-14-2, the strain SAI4- 14-2 was passaged on primary hamster kidney （ PHK ） cells for 18 generations, the nueleotide sequences for E gene of various passaged viruses were amplified by RT-PCR and sequenced, then compared the sequences with those from attenuated strain SA14-14-2 in Genebank （D90195）. The result showed that the sequences of nueleotide and amino acid of PHK6, PHKT, PHK8 were identical to those from D90195. The homology of nueleotide sequences of PHK13, PHK18 compared with those from D90195 were 99.8%, 99.7% respectively, and homology of amino acid sequences of PHK13, PHK18 compared with those from D90195 were 99.6%, 99.4% respectively. The attenuation-related amino acids of E protein for passaged viruses did not belong to reverse mutation. It showed that the attenuated virus strain SA14-14-2 was genetically stable. It indicates that both the strain SA14-14-2 and the vaccine prepared by using this strain as a seed are safe on molecular level.