猪传染性胃肠炎病毒江苏株的分离与鉴定及其S基因序列分析

Isolation and Identification of Porcine Transmissible Gastroenteritis Virus JS2012 Strain and Clone and Sequence Analysis of Its S Complete Genome

应用ST细胞,从临床上表现为腹泻症状的病死仔猪肠内容物中分离得到一株病毒,并对该病毒进行RTPCR,直接免疫荧光与动物回归等试验,证实该病毒为猪传染性胃肠炎病毒(TGEV),命名为JS2012株。应用PCR方法克隆出其初代(P1TS)与50代(P50TS)的S基因片段,进行序列测定,并将该基因序列与已发表的18个不同来源的TGEV毒株进行同源性和亲缘关系的比较分析。结果表明,各毒株间核苷酸同源性为96.0%～99.9%,氨基酸的同源性为96.5%～99.9%。TGEVJS201PITS株与中国江苏省HN2002株和美国Miller M6亲缘较近,表明不同地区分离毒株的S基因差异不大,而与P1TS相比,P50TS的S基因在1 124～1 129位置有6个碱基的缺失,对比发现,这种变异接近于弱毒株Purdue P115株所发生的变异,提示所发生的缺失可能与病毒毒力的减弱相关。

By serial passaging on ST cells ,a transmissible gastroenteritis virus （TGEV）strain（TGEV JS2012）was obtained from intestinal contents of died piglets with clinical diarrhea symptom .This virus was proved to be TGEV by RT-PCR,direct immunofluorescence and animal regression test .The S gene of TGEV JS2012 strain primary aassages （P1TS）and the fiftith passages（P50TS）,were amplified by PCR and then sequenced .Comparison of the S gene se-quences of P1TS and P50TS with 18 published TGEV strains with different origins showed that they can share 96.0%-99.9%homology of nucleotide sequences and 96 .5%-99 .9%homology of amino acids .Furthermore ,the results of the phylogenetic tree analysis demonstrated that there was a close genetic relationship between P 1 TS strain and HN2002 or Miller M6 strain isolated from China and America respectively .Generally the result indicated the varia-tion of S gene between strains of different origins was not so obvious .The result also showed that a deletion of six bases happened in 1 124-1 129 location of the S gene of P50TS seemed to be similar to Purdue P115 strain which is an attenuated strain ,indicating this deletion perhaps is related to the reduced virulence of TGEV .