UTILIZING THE MACROPOROUS PACKED-BED FOR INSECT CELL BACULOVIRUS EXPRESSION PART 2 - THE PRODUCTION OF HUMAN INTERLEUKIN-5 IN POLYURETHANE FOAM AND CELLULOSE FOAM PACKED-BED BIOREACTORS

Due to their high porosity and biocompatibility, polyurethane foam (PU F) and cellulose foam were adopted for insect cell immobilization and baculovirus expression. Spodoptera frugiperda (SF-21) cells were grown within the macroporous matrix and then infected by Autographa califor nica nuclear polyhedrosis virus (AcNPV) which was encoded with human i nterleukin-5 (hIL-5) gene. An appropriate initial cell loading density and medium circulation velocity determined from the previous study we re applied in this actual cell cultivation experiments to obtain a uni form initial and final axial cell distribution. The growth of insect c ells and the expression of baculovirus were successful in the macropor ous packed bed systems used. The final average cell density in cellulo se foam achieved was 5.2 x 10(7) cells/cm(3) and 4.3 x 10(7) cells/cm( 3) in PUF. Under the conditions of sufficient nutrition and oxygen sup plement, the average productivity of hIL-5 in cellulose foam packed be d bioreactor reached 7.2 x 10(7) unit/1-day. With 50% fresh medium rep lacement after viral infection, the average productivity of hIL-5 in P UF packed bed reached 8.4 x 10(7) unit/1-day, about two fold than that without any fresh medium replacement at infection.