Expression of Recombinant Factor IX Using the Transient Gene Expression Technique

Pilot and large-scale production of recombinant proteins requires the presence of stable clones capable of producing large quantities of recombinant proteins. Not only the process of selecting stable clones is time consuming, but also the continuous culturing of clones in large-scale production may cause loss of incoming plasmid and recombinant genes. Thus, considering the advancement in Transient Gene Expression (TGE) technology for recombinant protein expression, the large-scale expression of factor IX (FIX), as a recombinant protein, was investigated in mammalian HEK cells by TGE technique in the present research. HEK cells were seeded in cell factory and then transfected by pcDNA-hFIX plasmid using calcium phosphate co-precipitation method. Stable HEK-hFIX cells were also seeded in cell factory, separately. After adding Vitamin K, recombinant FIX was quantified in conditioned media using an ELISA. Moreover, its functional activity was examined using an aPTT assay. The results showed that the expression and activity of FIX by TGE technology was respectively 1.6 and 1.5 times higher than that obtained through stable HEK-FIX cells. HEK cells with higher transfectability seemed to be an appropriate alternative for transient expression for proteins large-scale production.