ENHANCED PRODUCTIVITY OF HYBRIDOMA AND RECOMBINANT CHO CELL CULTURES BY PLURONIC F-68 AND OTHER MEDIUM COMPONENTS, AND BY INCREASED PERFUSION RATES, IN FLUIDIZED-BED BIOREACTORS

Abstract

Hybridoma and Chinese Hamster Ovary (CHO) cells are cultured in continuous fluidized-bed bioreactors. Cells are immobilized in porous, weighted collagen microspheres which are suspended in the bioreactor by the recycling of culture liquid. This paper presents experimental data showing the response by hybridoma and recombinant CHO cells to changes in the culture environment brought about by varying process parameters. The effect of perfusion rate changes, and limiting nutrient concentration on specific productivity and metabolic characteristics, was studied. Perfusion rates in the range of 0.5–2.5 mL/mL fluidized-bed/hr were investigated. Significant improvements in both population specific productivity and reactor space-time productivity were observed at high perfusion rates. Specific metabolic rates, such as glucose and glutamine consumption rates and lactate and ammonia production rates, increased with increases in perfusion rate, whereas by-product yield coefficients, e.g., lactate yield on glucose and ammonia yield on glutamine, remained unchanged. In addition, studies have been carried out with a number of culture media components that enhance the productivity of hybridoma cells and recombinant CHO cells. Results show that pluronic F-68 when added to serum-free culture medium enhances the productivity of both hybridoma and recombinant cell cultures in a stable manner. This enhanced productivity appears to result from an increase in cell number for hybridomas, whereas enhancement of recombinant CHO cell productivity is the result of an increase in the cell-specific productivity.