Achievement of high cell density and high antibody productivity by a controlled-fed perfusion bioreactor process

Controlled feeding of nutrient supplements to a cell culture to enhance mon oclonal antibody productivity has been practiced widely in high-yield, fed- batch processes. In this study, a similar feeding concept has been applied to a perfused culture and evaluated for the effects on bioreactor productiv ity and product quality. Our experimental results show that, by using such a "controlled-fed perfusion" approach, the volumetric antibody productivity (antibody per liter per day) was significantly increased by nearly twofold over the perfusion process, and surpassed fed-batch and batch processes by almost tenfold. The substantial boost in the overall productivity is attri butable primarily to the combined effects of increased cell density as well as reduced product dilution. Both were achieved through careful nutrient s upplementation in conjunction with metabolite minimization. As the manufact uring process evolved from roller bottles to the controlled-fed perfusion b ioreactor system, the immunoreactivity and the cDNA sequences of the antibo dy were well preserved. However, the product glycosylation distribution pat terns did alter. The controlled-feed perfusion process demonstrated a uniqu e encompassment of the advantages of fed-batch and perfusion methods; that is, high product concentration with high volume throughput. Therefore, it m ay be very suitable for large-scale production of monoclonal antibodies. (C ) 2000 John Wiley & Sons, Inc.