The protective effect of serum against hydrodynamic damage of hybridoma cells in agitated and surface-aerated bioreactors.
The effect of serum on the growth rate and metabolism of CRL-8018 hybridoma cells in an agitated, surface-aerated bioreactor was examined. In the employed well-controlled bioreactors at high agitation rates, hybridoma cells in medium containing 1% fetal bovine serum rapidly die in the presence of a vortex with accompanying gas-bubble entrainment, whereas non-agitated control cultures grow normally in medium containing 1% serum. Serum levels greater than 5% counteract the detrimental hydrodynamic effects due to agitation and bubble entrainment. The protective effect is present after short-term (less than 1 h) exposure to 10% serum concentration, suggesting a protection mechanism which is, at least in part, of a physical nature. The apparent cell yields on glucose, lactate, and glutamine decreased with decreasing growth rate due to low serum concentrations. The results are incorporated into a simple model in which the apparent growth rate is the sum of an invariable growth rate and a changing death rate.