INSULIN UTILIZATION AND KINETIC EFFECT ON HYBRIDOMA METABOLISM IN BATCH AND CONTINUOUS CULTURES

This paper discusses the insulin utilization kinetics and the effect o f its concentration during batch and continuous mass cultures of the m urine VO208 hybridoma cells, using a home-made serum-free medium. Our results show that insulin is utilized by the cells, with a specific ra te of 1 relative units (RU) per 10(9) cells per h in batch culture. In continuous reactor running at different insulin levels, this consumpt ion rate is observed to vary from 0.13 to 0.55 RU per 10(9) cells per h when the insulin activity increases from 0.3 to 35 RU l(-1) and then to stabilize for higher insulin levels until 110 RU l(-1). A low insu lin amount in the medium around 0.01 RU l(-1), which is near physiolog ical levels, is found sufficient to promote the cell growth. Interesti ngly, we observe that too high insulin levels, above 25 RU l(-1), indu ce a reduction of the cell density due to an inhibitory effect on the maximal specific cell growth rate. Furthermore, the specific rate of M Ab production is found to be independent of the insulin amount in the medium.