Patent ID: 7070960

Claim:
A method of optimizing the condition for product expression in animal cell culture wherein the concentration of a solute of interest in a culture medium composition for optimal product expression is different from the concentration of said solute in the culture medium composition determined for optimal cell growth, which method comprises: a) growing the animal cell culture in a culture medium to determine the condition for optimal cell growth; b) varying the concentration of the solute in the culture medium to a concentration above that optimal for cell growth, which concentration is effective to create an environment of solute stress on the cell culture as expressed by an inhibitory effect on cell growth or cell density of said cell culture while monitoring the product expression as concentration of the solute is varied in the culture medium to detennine optimal product expression; and c) selecting the solute concentration that provides the optimal combination of cell growth and product expression, wherein said solute is selected from the group consisting of an inorganic salt or ion thereof, an organic polyol, and a metabolite.