降钙素原抗原的表达及其抗体的制备与初步鉴定

目的:构建降钙素原(PCT)原核表达载体, 制备其多克隆抗体(pAb)和单克隆抗体(mAb), 并进行特性鉴定.方法:以甲状腺癌细胞cDNA文库为模板, 构建重组表达质粒pGEX- 4T-1-PCT和PET-32a-PCT, 在大肠杆菌中分别表达GST-PCT和His-PCT融合蛋白, 用His-PCT免疫家兔和BALB/c小鼠制备兔pAb和鼠mAb.通过ELISA法测定抗人PCT抗血清效价;用Western blot、 间接免疫荧光鉴定pAb的特异性.使用间接ELISA法筛选分泌特异性抗PCT的杂交瘤细胞株, 采用Western blot和间接免疫荧光鉴定mAb的特异性. 结果:构建了重组表达质粒pGEX- 4T-1-PCT和PET-32a-PCT, 并在大肠杆菌中表达、纯化.经ELISA法测得抗人PCT抗血清效价是1∶ 256 000.制备的抗PCT兔多克隆抗体可特异地识别重组和天然的PCT蛋白.获得8株可稳定分泌抗PCT的杂交瘤细胞株, 可识别重组人PCT蛋白, 其中有4株可特异性结合TT细胞质中的天然蛋白. 结论: 成功地制备出兔抗人PCT抗血清和8株抗PCT的mAb, 为进一步研究PCT在严重的细菌感染和脓毒症中的病理及生理作用奠定了基础.

Expression of procalcitonin and characterization of antibodies against PCT

AIM: To construct the expression vectors of procalcitonin (PCT), prepare polyclonal antibodies (pAbs) and monoclonal antibodies (mAbs) against PCT and identify their specific biological activity. METHODS: The recombinant expression plasmids of pGEX-4T-1-PCT and PET-32a-PCT were constructed using thyroid carcinoma cell line (TT cell) cDNA as template. The fusion protein of His-PCT was expressed in E.coli and used as immunogen. The specificity of antiserum against human PCT was characterized by ELISA, Western blot and indirect immunofluorescence. The mAbs against human PCT were identified by Western blot and indirect immunofluorescence. RESULTS: The recombinant expression plasmids of pGEX-4T-1-PCT and PET-32a-PCT were constructed and the fusion protein of His-PCT was expressed and purified. The antiserum against human PCT was prepared and the titer detected by ELISA was 1:256 000. The pAb specifically recognized the recombinant human PCT. Eight hybridoma cell lines secreting specific mAbs against PCT were established. The mAbs recognized the recombinant human PCT and four of them recognized the native PCT of TT cytoplasm in immunofluorescent assay. CONCLUSION: The successful preparation of polyclonal and monoclonal antibodies against human PCT is beneficial to further research into the pathological and physiological functions of PCT in severe bacterial infection and sepsis.