CHO CELL-GROWTH AND RECOMBINANT INTERFERON-GAMMA PRODUCTION - EFFECTSOF BSA, PLURONIC AND LIPIDS

The role of bovine serum albumin in mammalian cell cultures and the po ssibility of its substitution by other components in a serum-free medi um has been investigated. In this study, BSA was shown to be important for growth and product formation in CHO cells expressing recombinant human interferon-gamma. There were indications that its stimulating gr owth effect was dependent on the source of BSA used and probably was r elated to the purification procedure used for the production of the de sired albumin fraction. Cell growth did not occur in the absence of BS A but at low concentration (1 mg ml(-1)) it was stimulated by the addi tion of a combination of a commercial lipid mixture plus Pluronic F68. However, under the latter conditions IFN-gamma production was adverse ly effected. The importance of individual lipid components was investi gated using a statistical approach based on a Plackett-Burman design. Linoleic acid was identified as a positive variable for cell growth wh ile cholesterol was identified as a negative variable for both cell gr owth and IFN-gamma production. When a combination of linoleic acid plu s Pluronic F68 was included in the formulation of low BSA medium, cell growth was similar to that at high BSA concentration (5 mg ml(-1)) bu t the IFN-gamma concentration was significantly reduced (ca. 45%).