猪瘟疫苗中牛病毒性腹泻病毒2型的检测

为对上海某猪场送检的一份猪瘟疫苗进行牛病毒性腹泻病毒(BVDV)检测,本研究将猪瘟疫苗样品接种于MDBK细胞,盲传15代后仍无致细胞病变效应,但间接免疫荧光试验表明接种该疫苗后的MDBK细胞能够被单克隆抗体BZ-53(BVDV-2)识别。采用BVDV-1和BVDV-2的5’-UTR的通用检测引物和针对BVDV E2的引物,对样品RNA进行RT-PCR检测,结果显示,样品能够扩增出约288 bp的BVDV特异性片段;此外,5’-UTR和E2基因片段的测序分析结果表明分离株属于BVDV-2,并且其E2基因与牛源XJ-04株(BVDV-2)的E2基因同源性最高(92.3%),而与猪源ZM-95株(BVDV-1)的E2基因同源性较低(64.5%)。由此证明,该猪瘟疫苗中的确污染有一株BVDV-2株。

Identification of bovine viral diarrhea virus 2from classical swine fever vaccine

In this study,a classical swine fever(CSF) vaccine suspected of being contaminated with bovine viral diarrhea virus(BVDV) was examined for BVDV contamination.The CSF vaccine sample was passaged in MDBK cells which showed no cytopathic effect at even 15 blind passages,but the culture cells were strong positive reacted with monoclonal antibody against type 2 BVDV(BVDV-2) by immunofluorescence antibody assay.In addition,a specific fragment of 288 bp was amplified from the vaccine sample with the BVDV 5’-UTR primers.Furthermore,The DNA fragments of 5’-UTR and E2 gene were amplified by PCR and sequenced.The results confirmed that the isolate was BVDV-2 and the homology of the E2 gene was most similar to cattle BVDV-2 XJ-04 strain(92.3%),but had the lower identities with ZM-95(64.5%).It was suggested that the CSF vaccine was contaminated with BVDV-2.