人重组CD137-Fc分子的构建与真核表达

Construction and eukaryotic expression of human CD137-Fc chimeric molecule

目的 构建人CD13 7 Fc基因的真核表达质粒 ,并表达有生物学活性的纯化人CD13 7 Fc融合蛋白。方法 从cDNA文库中用PCR扩增CD13 7全长编码基因 ,并导入真核表达载体pcDNA3中。测序证实后 ,继续用PCR扩增其膜外区cDNA ,,酶切后与hIgG1Fc基因一起装入真核表达载体pcDNA3中 ,转染 2 93T细胞瞬时表达 ,用夹心ELISA检测其表达情况 ,经蛋白A亲和纯化 ,用SDS PAGE与免疫印迹进行鉴定。结果 测序证实构建的CD13 7与CD13 7 FccDNA阅读框完整 ,连接部位序列正确 ;ELISA证实CD13 7 Fc蛋白的表达 ;SDS PAGE与免疫印迹证实其为人CD13 7 Fc蛋白。结论 获得了纯化的hCD13 7 Fc融合蛋白 ,为探讨CD13 7在免疫自稳调节中的地位 ,以及探索CD13 7的其它生物学功能奠定了坚实的实验基础。

Objective To construct eukaryotic expression plasmid of hCD137 Fc gene and express hCD137 Fc fusion protein with high biological activity. Methods PCR technique was employed to clone the human CD137 cDNA from a normal human activated T cells cDNA library, and then clone its extramembrane encoding region. The extramembrane sequence together with human IgG1 Fc cDNA were inserted into the eukaryotic expression plasmid pcDNA3. CD137 Fc gene was expressed transiently in 293T cells, and then CD137 Fc protein was purified by recombinated protein A affinity chromatography column. At last, the MW, purity and antigenicity of CD137 Fc were identified by sandwich ELISA, SDS PAGE and Western blotting, respectively. Results The ORF of CD137 Fc gene was coincident with what we expected. ELISA and SDS PAGE confirmed protein expression in 293T cells. Western blotting proved the antigenicity of the purified CD137 Fc protein. Conclusion We obtained a purified recombinated CD137 Fc protein with biological activity and the expected MW. This lays the foundation for further studies of CD137 such as its role in immune homeostasis and other biological functions.