人前列腺特异性抗原的原核表达及多克隆抗体制备

目的：建立人前列腺特异性抗原（prostate specific antigen,PSA）的可溶性大肠杆菌表达系统,获得高活性重组人PSA及多克隆抗体,为临床相关疾病的监测、诊断和治疗提供关键材料。方法：构建可溶性表达载体pET-S1-S2-PSA质粒,采用化学法将pET-S1-S2-PSA质粒转化大肠杆菌BL21（DE3）细胞,IPTG诱导BL21（DE3）细胞表达rPSA,阳离子交换层析纯化rPSA,经Western印迹鉴定后免疫大耳白兔制备PSA抗体,ELISA法检测抗体效价。结果与结论：构建了可溶性表达载体pET-S1-S2-PSA,获得了可溶性高表达rPSA的BL21（DE3）细胞株,并制备了可特异性结合天然PSA的抗体,其效价在1∶20000以上。

Expression of human prostate specific antigen in Escherichia coli and preparation of PSA polyclonal antibody

Objective：To construct the recombinant plasmid with human prostate specific antigen（PSA） gene expressed in E. coli in a soluble form and obtain PSA polyclonal antibody. Methods：The coexpression vector pET-S1-S2-PSA was constructed and transformed into E. coli BI2.1 （DE3）. The bacteria containing the expression plasmid were induced to ex- press the fusion protein by IPTG. After purification by cation-exchange chromatography, the relative molecular mass and expression form of the target fusion protein were analyzed by SDS-PAGE and Western blot. The rabbits were immunized with the recombinant protein and the rabbit polyclonal antibody in serum was identified by ELISA. Results and Conclusion：The soluble PSA fusion protein was successfully expressed in E. coli BL21 （DE3）. The valence of antibody in the rabbit serum was over 1：20 000. The anti-PSA rabbit serum can be used as a diagnostic reagent.