Effects of Serum and Growth Factors on HEK 293 Proliferation and Adenovirus Productivity

Abstract

The effect of serum on cell growth and virus production in both basal and serum free media was examined in Human Embryonic Kidney (HEK) 293. A 40-fold decrease in virus titre was observed in Dulbecco's Modified Eagles Medium (DMEM) cultures supplemented with 10% FBS when compared to 1% FBS. However, a 90-fold increase in virus titre was observed in DMEM supplemented with 1% FBS as compared with EX-CELL™ 293 serum free culture. A similar effect was also seen for the efficiency of gene transfer as indicated by the expression level of GFP. The results demonstrated that although serum at higher concentrations has a negative and dose-dependent effect on titre its supplementation in small quantity is essential for virus productivity. The effect of Insulin-like growth factors on proliferation of HEK 293 cells as well as on infection and specific productivity was also studied in serum free media. It was found that LONG™ R 3 IGF-1, an analogue of IGF-1 promotes cell proliferation and viability more effectively than Insulin and IGF-1. Similarly, cultures supplemented with LONG™ R 3 IGF-1 showed relatively higher virus productivity in comparison to other supplemented cultures but virus productivity was found to be significantly (p < 0.05) higher when there were no growth factors at all.