Aim: To construct eukaryotic expression vector and express human interleukin 18 (hIL-18) in Pichia pastoris.
Methods: The gene encoding of hIL-18 was amplification by PCR. The recombinant pPICZaC/hIL-18 was transformed into the Pichia pastoris X-33 strain via electroporation. The high level expression was selected and assayed by the methods of PCR, SDS-PAGE and Western blot. The rhIL-18 was purified by the methods of hydrophobic chromatography and anion exchange chromatography. The bioactivity of it was initially assayed.
Results: The rhIL-18 was secreted into the supernatant and the concentration reached to 202 mg/L. The rhIL-18 was further identified by Western blot with specific antibody binding activity. The purity of the rhIl-18 reached about 95%. And rhIL-18 can synergistically induce PBMC to produce IFN-gamma with IL-2.
Conclusion: A rhIL-18 is successfully constructed and expressed in Pichia pastoris. And this contributes to further study of its function and activity.