Metabolically optimised BHK cell fed-batch cultures

The aim of this work was the optimisation of a fed-batch culture by metabol ic confinement of BHK21 cells producing an antibody/cytokine fusion protein with potential application in tumour-targeted therapy. Previous results sh owed that at very low nutrient concentrations, a metabolic shift towards mo re efficient metabolic pathways occurs. The application of those results in the optimisation of a fed-batch culture resulted in higher cell growth (0. 020 vs. 0.016 h(-1)) and cell viability, higher maximum cell concentration (2.5 vs. 1.1 x 10(6) cell ml(-1)), longer culture span (17 versus nine days ) and higher product titre (60% increase), in relation to batch culture. Th is was achieved by maintaining glucose at 0.3 mM and glutamine at 0.2 mM th rough the addition of a concentrated solution based on the estimations of f uture nutrient consumption and growth rates through off line measurements. The production of toxic metabolites such as lactate and ammonia was reduced , especially the lactate production, which was markedly decreased due to th e metabolic confinement of the cells. In conclusion, it was possible to inc rease the final titre of the recombinant antibody/cytokine fusion protein b y confining the metabolism of the cells to an energetically more efficient state. (C) 2000 Elsevier Science B.V. All rights reserved.