传染性法氏囊病病毒VP2基因的扩增与序列分析

Gene amplification and sequence analysis of VP2 gene of infectious bursal disease virus

为了解凉山地区传染性法氏囊病病毒(IBDV)的分子特征,利用实验室采集保存的感染IBD的法氏囊提取出总RNA,采用RT-PCR方法对IBDV VP2基因进行扩增,测序后与GenBank中的参考序列进行比对分析.结果表明,试验成功扩增出1369 bp的VP2基因片段;样品与弱毒株和经典毒株的核苷酸同源性高达98.4%-99.6%;系统发生树表明样品中的IBDV与弱毒株B87亲缘关系最近;样品与弱毒株的氨基酸序列同源性为98.9%-99.1%;样品中的IBDV分子特征完全符合弱毒类型的特征,样品与弱毒株的抗原性基本一致,推测样品中的IBDV应与弱毒株或疫苗毒株同一来源.该毒株与疫苗用毒株亲缘关系最近,且IBDV疫苗多为活疫苗,因此,试验结果说明凉山地区IBDV免疫接种率可能较高,但应该拟定更合理的免疫程序.

In order to study the molecular characteristics of infectious bursal disease virus in Liangshan area,total RNA was ex tracted from the IBD infected bursa that was collected in the laboratory,and then the VP2 gene of IBDV was amplified by RT-PCR and compared with the reference sequences downloaded from GenBank.The results showed that the 1369bp VP2 gene fragment was successfully amplified,and the nucleotide homology of the samples with the attenuated strains and the classical strains was as high as 98.4%~99.6%.The phylogenetic tree indicated that the IBDV in the samples to the attenuated strain B87 was the closest,the amino acid sequence homology of the sample with the attenuated strains was 98.9%~99.1%,and the molecular characteristics of the IBDV in the sample completely accorded with the characteristics of the attenuated type,and the antigenicity of the sample and the attenuated strains were basically the same,from which it was inferred that IBDV in the samples should be from the same source with attenuated strains or vaccine strains.The test results showed that the immunization coverage rate of IBDV was high in Liangshan area,but more reasonable immune procedures should be developed.