肠出血性大肠杆菌O157∶H7毒力蛋白NleB1的表达、纯化及多克隆抗体的制备与鉴定

摘要

目的：构建肠出血性大肠杆菌（ EHEC） O157∶H7毒力蛋白nleB1基因的原核表达载体，诱导表达重组蛋白，制备NleB1的抗血清。方法从EHEC O157∶H7 EDL933株的全基因组中PCR扩增出编码nleB1的990个碱基序列，构建原核表达载体pET24a-nleB1，将构建的重组表达载体的质粒pET24a-nleB1转化至大肠杆菌BL21（DE3）感受态细胞中，利用异丙硫半乳糖苷（IPTG）诱导融合蛋白His-NleB1表达，并利用镍柱进行亲和层析纯化和切胶纯化，以纯化后的融合蛋白His-NleB1为抗原免疫BALB/c小鼠，获得抗血清。 Western印迹和ELISA法鉴定获得的抗血清。结果成功构建了pET24a-nleB1原核表达载体，纯化得到融合蛋白His-NleB1，进而免疫BALB/c小鼠制备多克隆抗体，Western印迹和ELISA法证实多克隆抗体制备成功。结论成功获得了EHEC O157∶H7的毒力蛋白NleB1的多克隆抗体，为研究EHEC O157∶H7毒力蛋白NleB1的功能奠定了基础。%Objective To construct a prokaryotic plasmid expressing the recombinant protein of enterohemorrhagic Escherichia coli(EHEC) effector NleB1 and to prepare the polyclonal antibody of mouse anti-NleB1.Methods The nleB1 (990 bp) gene was amplified from the genome EHEC O157∶H7 and cloned into the expression plasmid pET24a to construct the recombinant plasmid pET24a-nleB1 that was transformed into E.coli BL21(DE3).After induction with isopropylthio-gelactoside( IPTG) , the His-tag fusion proteins were purified by Ni+affinity chromatography and gel slices.The polyclonal antibody was prepared by immunizing BALB/c mice with purified recombinant proteins and analyzed by Western blotting and ELISA.Results The pET24a-nleB1 recombinant plasmid was successfully constructed, the fusion protein was ex-pressed and purified,and the polyclonal antibody was obtained by immunizing mice with purified fusion protein.Western blotting and ELISA staining demonstrated that the polyclonal antibody was successfully obtained.Conclusion The prepara-tion of the polyclonal antibody against EHEC O157∶H7 NleB1 will be of help for further studies on the function of NleB1 protein.