Variation of amino acid concentrations in the medium of HU β-IFN and HU IL-2 producing cell lines.

There are different requirements for the nutrient medium of various mammalian cell lines. We have determined the behaviour of the amino acid concentrations in the medium of two growing cell lines used for producing human interleukin 2 and human interferon β constitutively. The experiments are based on a fermentation process with a bubble free cell culture aeration system with porous moving membranes, which allows production of high cell densities without foaming. We found interesting alterations in which the actual amino acid ratios are able to trigger consumption and production of a particular component depending on the supply of other possible replacements. Such data indicate the complicated biochemical network of synthesis, conversion and transport phenomena. Finally, we demonstrated the influence of product synthesis upon the amino acid requirements using as an example transformed hu IL-2- and hu β-IFN-producing mouse L-cells.