PURIFICATION AND ANTIGENICITY ASSAY OF HUMAN INTERLEUKIN-21 EXPRESSED IN E.coli

Objective To express coding gene of human interleukin-21(IL-21) in E.coli,purify its protein,and assay its antigenicity. Methods Human IL-21 gene fragments were obtained from human tonsil cDNA by PCR.The coding gene for the mature N terminus of IL-21 was inserted into prokaryotic expressing vector pGEX-4T-2 and transformed into E.coli DH5α.The expressed product was purified by affinity chromatography using GST Fusion Protein Purification bead and its antigenicity analyzed by Western Blotting. Results Induced by IPTG,E.coli DH5α expressed the right molecular weight protein.Western Blotting test showed the protein had reaction with IL-2 monoclonal antibody. Conclusion The vector pGEX-4T-2/IL-21 and engineering bacteria E.coli DH5α expressing IL-21 mature N terminus fusion protein is successfully constructed.By purification and Western Blotting test,the recombinant IL-21 revealed resemblant antigenicity to IL-2.