Statistical Design of Culture Medium for Recombinant Interferon-γ Production

A statistical optimization approach based on a Plackett-Burman design was used to identify important nutrient components for both CHO cell growth and IFN-γ production. Nutrient components of the serum-free culture medium were first subjected to this analysis. BSA was shown to be one of the major medium components; preliminary studies indicated that its stimulating growth effect was a nutritional one. Cell growth in BSA-reduced cultures supplemented with a combination of a commercial lipid mixture plus Pluronic F68 was similar to control cultures, but IFN-γ production was adverselly affected. A second statistical analysis was then carried out in order to investigate the importance of individual lipid components on those cultures. Linoleic acid was identified as a positive variable for cell growth while cholesterol was identified as a negative variable for both cell growth and IFN-γ production. When a combination of linoleic acid plus Pluronic F68 was included in the formulation of BSA-reduced medium, cell growth was similar to cultures with high BSA concentration. However, IFN-γ concentration was depressed to a large extent (ca. 45%). No accumulation of IFN-γ was found within the cell.