INDUCIBLE PRODUCTION OF ERYTHROPOIETIN USING NEW RUNAWAY-TYPE VECTOR BY MAMMALIAN-CELL CULTURE IN SPINNER FLASK

Human erythropoietin (HuEPO) gene was inserted into an SV40-based epis omal vector with a temperature-sensitive large T antigen which enabled uncontrolled plasmid replication and inducible HuEPO production at te mperatures below 33 degrees C. Good productivity of HuEPO was obtained when temperature was lowered to 30 degrees C at relatively higher cel l density in Petri dish culture. Therefore, we cultured the cells immo bilized on microcarriers in a spinner flask at 37 degrees C until the cell density reached 1.8 x 10(4) cells/cm(2)-microcarrier surface area , and then the temperature was lowered to 30 degrees C for HuEPO produ ction. Using this process, HuEPO productivity was enhanced 7-18 times that of the Petri dish cultures, and a high concentration of HuEPO was accumulated in the medium.