[The expression, purification and characterization of β-hCG protein in E.coli].

OBJECTIVE: To obtain β-chain human chorionic gonadotropin (β-hCG) fusion protein (β-hCG/GST) and identify its antigenicity. METHODS: The full-length gene of β-hCG was amplified by PCR. The PCR product was cloned into pET-42a prokaryotic expression vector to construct the recombinant plasmid pET-42a-β-hCG, and then it was transformed into BL21 (DE3) for β-hCG/GST fusion protein expression under IPTG induction. After SDS-PAGE assay, the fusion protein was purified by affinity chromatography and identified by Western blotting. The antigenicity of the purified fusion protein was characterized by ELISA. RESULTS: The β-hCG gene we obtained had an identical sequence to that retrieved in GenBank. The prokaryotic expression vector pET-42a-β-hCG was successfully constructed as confirmed by enzyme digestion and DNA sequencing. Both Western blotting and ELISA demonstrated that the purified β-hCG fusion protein had satisfactory antigenicity. CONCLUSION: The purified β-hCG/GST fusion protein with satisfactory antigenicity has been obtained, which will facilitate further study on active anti-tumor immunotherapy targeting β-hCG.