Development of an animal-component free medium for vero cells culture.

This work describes the development of an animal-component free medium (IPT-AFM) that allows an optimal growth of Vero cells, an adherent cell line used for the production of viral vaccines. Statistical experimental design was applied to identify crucial nutrients that affect cell growth. Using Medium 199 or MEM as a basal medium, a serum-free medium (SFM) referred as IPT-SFM that only enclosed transferrin as a component of animal origin was developed at first. Then, the composition of IPT-SFM was further improved to obtain an animal-component free medium named IPT-AFM. IPT-AFM contains M199 as a basal medium, plant hydrolysates, epidermal growth factor, ethanolamine, ferric citrate, and vitamin C. Among various plant hydrolysates, specific combinations of soy (Hypep 1510) and wheat gluten (Hypeps 4601 and 4605) hydrolysates, were identified to promote cell growth; whereas individual Hypeps had a minor positive effect on cell growth. Nevertheless, the removal of serum did influence cell attachment. Coating tissue-culture flasks with teleostean, a product extracted from cold water fish skin, had not only enhanced cell attachment but also improved cell growth performance in static cultures. Different non-animal proteases were also assessed as an alternative to trypsin. TrypLE Select, a recombinant trypsin, gave the best cell growth performances. Kinetics of cell growth in IPT-AFM were investigated in T-flasks, cell growth was comparable with that obtained in MEM+10% fetal calf serum (FCS). A mean cell division number equal to 2.26 +/- 0.18 and a specific growth rate micro 0.019 +/- 0.003 h(-1) were achieved in IPT-AFM.