[Expression of human IL-12 in mammalian cell and study on its biological activities].

OBJECTIVE: To obtain recombinant human interleukin 12 by genetic engineering, and to explore possibility of its clinical application in treatment of tumor and chronic hepatitis. METHODS: Bicistronic expression vector P35-IRES-P40 was constructed for the simultaneous translation of IL-12 p35 and p40 cDNA subunit through internal ribosomal entry sites (IRES). pCI-dhfr-P35-IRES-P40 vector was constructed for expression in CHO-DHFR- cells. Positively cloned cells were screened by means of ELISA. Pools of clones with increased expression of IL-12 could be generated by selection in methotrexate. To determine the biological activities of rhIL-12, PHA-activated lymphoblasts proliferation assay and IFN-gamma induction assay were used in this study. RESULTS: Genetically engineered cells expressing hIl-12 were obtained and all the cell lines showed the stabile expression of rhIL-12 in high efficiency and good growth properties. CONCLUSION: rhIL-12 have good biological activities, it can stimulate activation and proliferation of T cells and induce production of IFN-gamma.