猪塞内卡谷病毒VP1蛋白原核表达及多克隆抗体制备

Prokaryotic expression of porcine Seneca valley virus VP1 protein and preparation of polyclonal antibody

  • 摘要: 【目的】原核表达猪塞内卡谷病毒(Seneca valley virus,SVV) VP1蛋白,制备SVV-CH-HB2016 VP1蛋白多克隆抗体并分析其抗原性,为进一步研发SVV病毒诊断试剂盒和亚单位疫苗提供参考依据。【方法】对SVV-CHHB2016 VP1基因序列进行密码子优化,构建质粒pUCK/VP1-opt,双酶切后连接至pET-28a (+)载体,构建原核表达质粒pET-28a-VP1。将重组质粒pET-28a-VP1转化大肠杆菌BL21(DE3)分子伴侣感受态细胞,经IPTG诱导表达获得重组VP1蛋白。采用Western blotting方法分析VP1蛋白的反应原性,并以包涵体变性和复性方式纯化。随后将VP1蛋白免疫新西兰白兔,分离血清获得重组VP1蛋白的多克隆抗体。以间接酶联免疫吸附试验(ELISA)法测定抗体的效价水平,以Protein A+G Agarose抗体纯化试剂盒纯化多克隆抗体。通过Western blotting和间接免疫荧光抗体试验(IFA)法验证多克隆抗体与SVV-CH-HB2016毒株反应的特异性。【结果】成功构建原核表达质粒pET-28a-VP1,在IPTG终浓度为0.1 mmol/L、37℃诱导4 h条件下,重组VP1蛋白成功表达并主要以包涵体形式存在; Western blotting分析结果显示,重组VP1蛋白可与His-Tag Mouse mAb发生特异性结合,具有良好的反应原性;经变性和复性纯化的重组包涵体蛋白纯度和浓度均较高;采用间接ELISA法检测多克隆抗体的效价为1∶32000;纯化后的抗体无明显杂带,纯度大于90.0%; Western blotting和IFA鉴定结果表明,多克隆抗体可特异性识别SVV-CH-HB2016毒株,重组VP1蛋白具有较好的免疫原性。【结论】通过原核表达SVV VP1蛋白获得的重组VP1蛋白具有较好的抗原性,制备的多克隆抗体特异性良好,可作为诊断试剂盒及亚单位疫苗研制的候选抗原。

     

    Abstract: 【Objective】 The purpose of the study was to prokaryotically express porcine Seneca valley virus (SVV) VP1 protein,to prepare polyclonal antibody against SVV-CH-HB2016 VP1 protein,and to analyze its antigenicity,so as to provide reference for further development of SVV diagnostic kits and subunit vaccines.【Method】 The codon optimization of SVV-CH-HB2016 VP1 gene sequence was carried out, and the plasmid pUCK/VP1-opt was constructed. After double enzyme digestion,pET-28a(+) vector was connected,and the prokaryotic expression plasmid pET-28a-VP1 was constructed. The recombinant plasmid pET-28a-VP1 was transformed into Escherichia coli BL21(DE3) molecular chaperone receptor cells, and the recombinant VP1 protein was obtained by IPTG induction and expression. The reactivity of VP1 protein was analyzed by the Western blotting method, and purified by denaturation and renaturation of inclusion body. Then,the New Zealand white rabbits were immunized with VP1 protein,and the serum was isolated to obtain the polyclonal antibody of the recombinant VP1 protein. The antibody titer level was determined by indirect enzyme-linked immunosorbent assay(ELISA), and the polyclonal antibody was purified with Protein A+G Agarose antibody purification kit. The specificity of the polyclonal antibody reaction with SVV-CH-HB2016 strain was verified by Western blotting and direct immunofluorescent antibody assay(IFA) methods.【Result】 The prokaryotic expression plasmid pET-28a-VP1 was successfully constructed. The recombinant VP1 protein was successfully expressed and existed mainly in the form of inclusion body under the condition of IPTG final concentration of 0.1 mmol/L and induction at 37℃ for 4 h. The Western blotting analysis result showed that the recombinant VP1 protein could bind specifically to His-Tag Mouse mAb with good reactivity. The recombin antinclusion body protein purified by denaturation and renaturation had high purity and concentration. The titer of polyclonal antibody determined by indirect ELISA was 1:32000. The purified antibody had no obvious heteroband and the purity was more than 90.0%. The results of the Western blotting and IFA identification showed that the polyclonal antibody could specifically recognize SVV-CH-HB2016 strain,and the recombinant VP1 protein had good immunogenicity.【Conclusion】 The recombinant VP1 protein obtained by prokaryotic expression of SVV VP1 protein has good antigenicity, and the prepared polyclonal antibody has good specificity, which can be used as a candidate antigen for the development of diagnostic kits and subunit vaccines.

     

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