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.