雏番鸭细小病毒vp3基因的原核表达及增殖病毒的检测

近年来,番鸭细小病毒出现新的流行趋势,估计与病毒基因变异有关,因此针对新流行毒株研发新的检测方法很有必要。本研究根据番鸭细小病毒(MDPV)2012年分离株SAAS-SHNH的全基因序列,设计了一对特异性引物,利用PCR技术扩增全长vp3基因,经鉴定正确后,进行同源性比对分析,同时将其克隆到PET28a载体,构建成PET28a-VP3原核表达载体,经转化及IPTG诱导后,SDS-PAGE电泳和Western blotting分析,表达出与预期大小相符的63.1 k Da的蛋白,该蛋白可与临床采集的免疫过MDPV的番鸭血清结合,说明该蛋白可用于MDPV的血清学检测。将纯化后蛋白免疫新西兰大白兔,制备兔源MDPV-VP3蛋白的多克隆抗体,制备的兔源血清能够与MDPV疫苗弱毒株及J3D6株VP3蛋白发生特异结合;MDPV感染原代鸭胚成纤维细胞(DEF)后,利用兔源血清作为一抗进行免疫荧光分析(IFA)分析,在DEF细胞核和细胞质内均能检测到VP3蛋白,表明利用VP3蛋白制备的抗血清可以用于MDPV免疫荧光分析细胞增殖病毒的检测。这为今后MDPV的快速检测提供了技术基础。

Prokaryotic expression of vp3 gene of Muscovy duck parvovirus, and its antiserum preparation for detection of virus multiplication

New epidemic broke out in recent year which was suspected to be caused by variant Muscovy duck parvovirus (MDPV). For this reason, new MDPV detection methods are needed for the new virus strains. In this study, a pair of primers were designed according to the full-length genome of MDPV strain SAAS-SHNH, which were identified in 2012, and were used to amplify the vp3 gene of MDPV by polymerase chain reaction. After being sequenced, the vp3 gene was subcloned into the prokaryotic expression vector PET28a. The recombinant plasmid was transformed into E. coli BL21 and induced with IPTG. SDS-PAGE and Western blotting analysis showed the MDPV vp3 gene was successfully expressed. After being purified by Ni2+ affinity chromatography system, the recombinant protein was used as antigen to immunize rabbits to obtain antiserum. Western blotting analysis showed that the acquired antiserum could react specifically with VP3 protein of J3D6 strain and MDPV vaccine strain. The antiserum could also be used for detection of cultured MDPV from primary duck embryo fibroblasts by immune fluorescence assay (IFA). It could be concluded that the VP3 protein and its antibody prepared in the research could be used for detection of VP3 antiserum and antigen respectively.