A Study of the Construction of Different Expression Vectors Containing IL-2 Gene and Their Expressions in Eukaryotic Cells

The whole length cDNA of human IL-2 gene including signal peptide was obtained using PCR from the cDNA pool of mononuclear cells from human peripheral blood. Different expression plasmids were constructed: pSVK3-IL2 contained SV40 promotor and pLNCIL2, pLNSIL2, pLIL2SN contained CMV, SV40 and LTR promotor respeetively. The constructed plasmids were transfected into COS-7 and OTLL-2 cells by DEAE-Dextran, SA-liposome and electroporation. The IL-2 levels in cell culture medium were measured at different time after transfection. The results showed that the transfected IL-2 gene could be transiently expressed up to 5 days and the highest IL-2 production could be 28￣30 U/ml at 72￣96 hrs after transfection, with the maximum value of 50U/ml. The different expression levels of expression plasmids contained different promotors and in different target cells were compared.