摘要
马泰勒虫裂殖子表面抗原1(EMA-1)是用于马梨形虫病诊断的重要靶抗原之一。为建立实用有效的间接酶联免疫吸附试验方法,笔者根据马泰勒虫EMA-1基因序列设计并合成引物,将新疆株EMA-1全基因序列克隆于原核表达载体pGEX-4T-1上,构建pGEX-4T-1/EMA1重组质粒,转化至BL21(DE3)中,经IPTG诱导得到EMA-1融合蛋白,切胶纯化后作为包被抗原建立检测马泰勒虫抗体的rELISA方法。结果显示:(1)GST-EMA1蛋白相对分子质量56ku,与其理论值基本一致;(2)通过Western blot分析证明其具有很好的特异性和反应原性;(3)以GST-EMA1蛋白作为包被抗原建立的rELISA可明显区分马泰勒虫、驽巴贝斯虫阳性血清和健康马血清;批内和批间重复试验的最大变异系数分别为14.79%和11.06%;(4)使用建立的间接ELISA与cELISA商品试剂盒分别对新疆伊犁马场收集的96份马血清样品进行检测,检出阳性率分别为27.1%(26/96)和25.0%(24/96),两者总符合率为95.8%。结果表明,基于原核表达的GST-EMA1蛋白所建立的rELISA特异性、重复性好,检出率与马泰勒虫临床分离率接近,可为新疆马泰勒虫病(特别是隐性带虫马)的检测、监控提供有效手段。
The erythrocytic-stage surface protein, Equi Merozoite Antigen 1 （EMA-1）, is a major candidate for the development of a diagnostic antigen for equine piroplasmosis. The aim of the present study was to establish an indirect ELISA for practical use. According to the specific se- quence of EMA-1 genes of Theileria equi, a pair of primers was designed and synthesized. The EMA-1 gene of Xinjiang strain was cloned, and then was inserted into the prokaryotic vector pGEX-4T-1. The recombinant plasmid （pGEX-4T-1/EMA1） were transformed into Escherichia coli BL12（DE3）, and the GST-EMA1 protein was obtained by induction of IPTG. The fusion protein was purified by extracting the inclusion bodies with gel slices, and the purified protein was used as coated antigen for the establishment of indirect ELISA method to detect the antibody to Theileria equi. The results indicated that the expressed EMA-1 had an apparent molecular mass equi-infected horse sera from Babesia caballi-infected horse sera or normal horse sera; The intra- and inter-assay demonstrated that the coefficient of maximum variation was 14.79 % and 11.06% respectively; 96 serum samples collected from horses in the state of Yili, Xinjiang were used to compare the indirect ELISA and cELISA commercial kit, the resules showed that their positive rates of T. equi infection were 27.1% （26/96） and 25.0% （24/96） respectively, and the total coincidence rate was 95.8%. These results suggest that the GST-EMA1 protein expressed in E. coli could be a reliable immunodiagnostic antigen for indirect ELISA test and that provided the means of effective detecting and monitoring for T. equi （especially in recessive infection） in Xinjiang.
出处
《畜牧兽医学报》
CAS
CSCD
北大核心
2017年第9期1737-1743,共7页
ACTA VETERINARIA ET ZOOTECHNICA SINICA
基金
国家自然科学基金-新疆联合基金重点项目(U1403283)
