猪乙脑病毒分离株BSF．ZZ-1和BSF．ZZ-3在BHK-21细胞上的传代培养及E基因序列稳定性分析

Sequence Analysis of the E Gene of JEV Isolate BSF. ZZ-1 and BSF. ZZ-3 Passaged in BHK-21 Cells

为研究猪乙脑病毒(JEV)分离株遗传基因的稳定性,将JEV分离株BSF.ZZ-1和BSF.ZZ-3在BHK-21细胞上进行连续传代培养,并对其E基因的遗传稳定性进行了研究。结果表明,经连续传代60次后病毒E基因趋于稳定,BSF.ZZ-1毒株E蛋白氨基酸位点E21(A→V)、E200(T→A)、E244(G→E)、E279(M→K)和E426(G→D),以及BSF.ZZ-3毒株的E244(G→E)、E255(F→L)、E285(M→L)、E368(L→S)和E497(N→S)传代后发生稳定点突变。与JEV毒力相关的部分位点如E107、E138、E176、E177和E315遗传稳定性较高,经连续传代后均未发生突变,与疫苗株SA14-14-2相应位点完全一致。但是,另外一些位点的遗传稳定性较差,如BSF.ZZ-3的E279(M→K→M)出现反复突变。这些突变是否与JEV的宿主细胞适应性及毒力变化相关有待进一步研究。

In this paper ,the genetic stability of E gene of JEV isolates BSF .ZZ-1 and BSF .ZZ-3 passaged in BHK-21 cells(Baby hamster kidney cell line ) was studied.The results showed that the E gene is becoming stable after 60 passages in BHK-21 cells.After serial sucultivation,stable amino acid(aa) mutation happened at the sites E21(F→L),E200(T→A),E244(G→E),E279(N→S) and E426(G→D) in isolate BSF.ZZ-1 and sites E244 (G→E),E255(F→L),E285(M→L),E368(L→S) and E97(N→S) in isolate BSF.ZZ-3.No mutations were ob-served at part of the virulence correlated aa sites ,such as E107,E138,E176,E177 and E315,similar to those of vaccine strain SA14-14-2.However,mutations at the virulence correlated aa sites of E279(M→K→M)of BSF.ZZ-3 happened repeatedly .Whether these mutations are correlated with the virulence variation and adaptability of JEV to host cells needs to be further studied .