A Study of Recombinant Factor IX in Drosophila Insect S2 Cell Lines Through Transient Gene Expression Technology

Background: Since the mass production of recombinant proteins requires the development of stable cell lines which is a time-consuming complex process, the use of transient expression on a large scale can be a comparatively useful alternative. Although various cell lines have been used for the expression of recombinant proteins, only a limited number of cells enjoy a high transfection characteristic and the ability to adapt to serum-free suspension culture easily. In the present study, the S2 cells from Drosophila insect with the ability to grow in suspension and serum-free cultures were used for the expression of factor IX (FIX) using Transient Gene Expression (TGE) technique. Methods: Drosophila Schneider (S2) cells were seeded in special roller bottles, and then, the cells were transfected with pMT-hFIX plasmid employing the calcium phosphate co-precipitation method. The stable S2-hFIX cells were also seeded in special roller bottles, separately. After the induction, recombinant FIX was quantified in conditioned media employing an ELISA. Moreover, its functional activity was examined using an aPTT assay. Results: The results showed that the expression of FIX through TGE technology was 1.6 times as high as that obtained through S2-FIX stable cells. Furthermore, the comparison of the FIX expression in S2 cells through TGE techniques with that obtained in previous studies in HEK cells or CHO cells revealed that S2 cells were more efficient in terms of FIX expression. Conclusion: The S2 cells with the capability to grow in suspension and serum-free cultures are a suitable alternative for transient expression for the large scale production of proteins.