猪流行性腹泻病毒LN-2015-1株分离鉴定及其S基因的变异分析

Isolation and identification of porcine epidemic diarrhea virus strain LN-2015-1 and its S gene mutation analysis

为了解辽宁猪流行性腹泻病毒(PEDV)来源及变异特性,经PCR诊断,细胞分离,细胞病变观察、RT-PCR以及S基因序列鉴定,成功分离1株PEDV毒株(LN-2015-1)。S基因序列分析显示,与CV777毒株相比,除点突变外,分离株还出现最长9bp的插入,6bp的缺失和13bp连续突变。氨基酸也存在最长3aa插入和2aa缺失,同时存在4处连续3个及以上的氨基酸突变,抗原表位分析表明在5个表位区共发生16个氨基酸的突变。同源性分析显示与HB-HA2015毒株的同源关系最近,序列相似性为99.2%,与2010年以来国内外代表变异毒株同源性较高,达到98.5%~98.8%,而与2010年以前的传统同源性较低,在93.2%~95.6%之间;进化树分析显示该毒株与近年来国内外流行的变异毒株属于同一群,并且与HB-HA2015形成一小的分支,而与传统毒株进化距离较远。

In order to understand the porcine epidemic diarrhea virus （PEI）V） origin and variant characteristics in Liaoning province, diagnosed by PCR, separated by Veto cell,and identified by cell pathological observation,RT-PCR and S gene sequence analysis, 1 PEDV strains （LN-2015-1） was successfully isolated from a pig farm of Liaoning province. Analysis of S gene sequence showed that compared withCV777 strain,there were the longest 9 bp insertion, 6 bp deletion and 13 bp continuous mutation in addition to point mutation. There also were the longest 3 AA insert, 2 AA deletion, and 3 AA or more continuous mutation. The epitope analysis showed that there were 16AA mutations in the 5 epitope regions. Homology analysis show that it had the highest se- quence similarity of 99.2% with HB-HA2015 strain,higher sequence similarity of 98.5%-98.8% with the domestic and foreign representative strains isolated since 2010, and lower sequence similarity of 93.2%-95.6% with the traditional strain isolated before 2010;the phylogenetic analysis showed that LN-2015-1 was clustered into the same group with home and abroad variation strain in recent years,and formed a small subgroup with HB-HA2015 at the same time. The evolutionary distance was far from the traditional strains.