瑶山亚种树鼩IFN-β和IFN-γ原核表达及其多克隆抗体制备

Prokaryotic expression and polyclonal antibody preparation of IFN-β and IFN-γ of Tupaia belangeri yaoshanensis

  • 摘要: 【目的】构建瑶山亚种树鼩IFN-βIFN-γ基因原核表达载体,并制备IFN-β和IFN-γ多克隆抗体,为进一步研究树鼩病毒感染动物模型打下基础。【方法】以瑶山亚种树鼩外周淋巴细胞为原材料,提取总RNA后经RT-PCR扩增瑶山亚种树鼩IFN-βIFN-γ基因,亚克隆至质粒pcDNA3.1(+)上构建真核表达载体,并瞬时转染仓鼠肾细胞(BHK-21);同时亚克隆到原核载体pET-28a(+)上构建原核表达载体,转化大肠杆菌BL21(DE3)感受态细胞后以IPTG诱导表达融合蛋白IFN-β和IFN-γ。融合蛋白纯化后免疫小鼠制备多克隆抗体,并利用Western blotting和间接免疫荧光(IFA)检测分析其反应性。【结果】扩增获得的瑶山亚种树鼩IFN-βIFN-γ基因片段分别为564和501 bp,亚克隆至质粒pcDNA3.1(+)上成功构建了真核表达载体pcDNA3.1-IFN-β和pcDNA3.1-IFN-γ,亚克隆到原核载体pET-28a(+)上成功构建获得原核表达载体pET-28a-IFN-β和pET-28a-IFN-γ。原核表达载体pET-28a-IFN-β和pET-28a-IFN-γ转化BL21 (DE3)感受态细胞后在30℃下以0.5 mmol/L IPTG诱导6 h即获得融合蛋白IFN-β和IFN-γ,且融合蛋白主要以包涵体形式表达,以含2 mol/L尿素的洗涤液洗涤后可获得纯度相对较高的融合蛋白,且损失较少。纯化的融合蛋白IFN-β和IFN-γ经乳化后免疫小鼠,成功制备获得IFN-β和IFN-γ多克隆抗体,Western blotting和IFA检测结果均显示这2个多克隆抗体具有良好的反应性。【结论】通过原核表达系统可在大肠杆菌中成功诱导表达获得瑶山亚种树鼩IFN-β和IFN-γ,复性后的融合蛋白具有良好的反应性和免疫原性,免疫小鼠制备获得的多克隆抗体反应性良好且抗体效价高,可作为检测工具用于研究瑶山亚种树鼩病毒感染模型。

     

    Abstract: 【Objective】To construct prokaryotic expression vector of IFN-β and IFN-γ genes in Tupaia belangeri yaoshanensis and prepare their polyclonal antibody,so as to lay the foundation for further research on animal models for viral infections of tree shrew.【Method】 Peripheral lymphocytes of T.belangeri yaoshanensis were taken as material and total RNA was extracted from them.IFN-β and IFN-γ genes,amplified by reverse transcription-polymerase chain reaction (RT-PCR),were subcloned into recombinant eukaryotic expression plasmids of pcDNA3.1 (+)to censtruct eukaryotic expression vector,and transiently transfected into renal cells of Cricetidae(BHK-21).At the same time,the genes were also were subcloned into prokaryotic vector pET-28a(+)to construct prokaryotic expression vector and transformed into Escherichia coli BL21(DE3)competent cell,and fusion protein of IFN-β and IFN-γ was induced by IPTG.Mice were immunized with purified recombinant proteins to obtain polyclonal antibodies of IFN-β and IFN-γ,and their reactivity were detected by Western blotting and indirect immunofluorescence assay(IFA).【Result】 Fragments of IFN-β and IFN-γ genes in T.belangeri yaoshanensis obtained through amplification were 564 and 501 bp.They were subcloned to plasmids of pcDNA3.1(+),so eukaryotic expression vectors pcDNA3.1-IFN-β and pcDNA3.1-IFN-γ were constructed;and they were subcloned to prokaryotic vector of pET-28a (+),so prokaryotic expression vectors pET-28a-IFN-β and pET-28a-IFN-γ were constructed.After prokaryotic expression vectors pET-28a-IFN-β and pET-28a-IFN-γ transformed into BL21(DE3) competent cell,fusion proteins of IFN-β and IFN-γ were obtained induced by 0.5 mmol/L IPTG for 6 h at 30℃.The fusion proteins were expressed in a form of inclusion body.After washing with a washing solution containing 2 mol/L urea,fusion proteins of relatively high purity could be obtained with less loss.Mice were immunized with purified and emulsified fusion proteins of IFN-β and IFN-γ to obtain polyclonal antibodies of IFN-β and IFN-γ.Western blotting and IFA results showed that these two polyclonal antibodies were of good reactivity.【Conclusion】With prokaryotic expression system induced in E.coli,IFN-β and IFN-γ in T.belangeri yaoshanensis was obtained;renatured fusion proteins are of good reactivity and immunogenicity.Polyclonal antibodies prepared through mice immunization were of good reactivity and high titer,and it can be taken as test tools for studying viral infection model of T.belangeri yaoshanensis.

     

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