Cloning and Expression of Human Interleukin-26 in Escherichia coli

This study focused on cloning human interleukin-26 (hIL-26) and expressing it in Escherichia coli (E. coli) efficiently. Two pairs of primers were synthesized in accordance with the hIL-26 gene reported by GenBank. The hIL-26 gene was cloned by nest PCR following the first round RT-PCR from human peripheral blood monocytes total RNA, and then the PCR product was cloned into pMD18-T vector. Colony PCR, restriction analysis, and sequence analysis showed that the cloned gene was the same as the reported hIL-26. The recombinant was cut with BamH I and EcoR I to obtain the hIL-26 fragment. The fragment was then inserted into pBV220 that was cut with the same enzymes. The recombinant expression vector was induced to express hIL-26 at 42 °C. SDS-PAGE analysis showed that the recombinant protein accounted for up to 20% of the whole protein of E. coli, and the protein was confirmed by Western blotting. Purity of the protein was found to be above 90% after purification with a molecular sieve. After renaturalization with glutathione buffer, its promoting effect on the production of IFN-γ in PBMC was detected by RT-PCR. A recombinant bacterial strain for expressing hIL-26 with biological activity was constructed successfully.