Construction of eukaryotic expression plasmid of porcine IL-18 gene and identification of bioactivity of its expressed protein.

【Objective】 The research was to construct eukaryotic expression vector of porcine IL-18 and detect bioactivity of its expressed protein.【Method】 Porcine IL-18 gene was amplified by PCR with recombinant plasmid pGEM-IL-18 as a template.The PCR product was digested with EcoRⅠand XhoⅠ,then inserted into eukaryotic expression vector pcDNA3.1(+) to generate an expression plasmid pIL-18 and transfected into the PK15 cells by lipofectamine 2 000.【Result】 Porcine IL-18 mRNA expression was found in the PK15 cells.SDS-PAGE and Western blot indicated that porcine IL-18 gene had already inserted into PK15 cell chromosome.The results showed that recombinant protein was about 22 ku.The recombinant protein can react with porcine IL-18 monoclonal antibody.Immunoenhancement effect of recombinant expression plasmid pIL-18 on swine influenza vaccine was observed by proliferation response of the T lymphocytes from spleen.It can obviously enhance the cell-mediated immune response.【Conclusion】 The recombinant plasmid pIL-18 was constructed,and its expression protein had bioactivity.