猪繁殖—呼吸道综合征病毒（PRRSV）CH—1a株基因型鉴定

根据猪繁殖－呼吸道综合征病毒（ＰＲＲＳＶ）美洲型毒株和欧洲型毒株的基因组序列设计合成了２对引物，即１００８ＰＳ／１００９ＰＲ和１０１０ＰＬＳ／１０１１ＰＬＲ。我国分离的ＣＨ－１ａ株用这２对引物均能扩增出与预期大小相符的ＲＴ－ＰＣＲ产物，分别与美洲型代表株（ＶＲ－２３３２）的ＲＴ－ＰＣＲ产物大小相当。特异性试验表明，这２对引物均不能扩增其他常见的繁殖障碍相关病毒的ＲＮＡ或ＤＮＡ以及未感染的ＭＡＲＣ－１４５细胞ＲＮＡ。间接免疫荧光试验也证明，ＣＨ－１ａ株与ＰＲＲＳＶ核衣壳蛋白特异性单克隆抗体以及美洲型毒株抗血清均呈阳性反应。因此初步证实ＣＨ－１ａ株为美洲型ＰＲＲＳＶ。

Genotyping of Porcine Reproductive and Respiratory Syndrome Virus Strain CH 1a Isolated in China by RT PCR and Indirect Immunofluorescence Test

CH 1a isolated from an outbreak of PRRS in a pig farm in China. Two sets of oligonucleotide primers, 1008PS/1009PR and 1010PLS/1011PLR were designed according to the sequences of PRRSV strain IAF exp91 and LV (European prototype) to determine the genotype of the PRRSV strain. The results showed that PRRSV strain CH 1a could be amplified using either primer pair by RT PCR, yielding a single band of the predicted size after agarose gel electrophoresis, to be similar in size to the products of strain VR 2332. No amplification was observed when RNAs were extracted from hog cholera virus (HCV) and uninfected MARC 145 cells or DNAs from pseudorabies virus (PrV). MARC 145 cells infected with strain CH 1a were shown to react with antisera against strains VR 2332 and NVSL (American isolate) by indirect immunofluorescence staining. Thus, it is concluded that the Chinese PRRSV strain CH 1a belongs to American genotype.