Patent ID: 8809049

Claim:
A method for producing one or more Chinese hamster ovary (CHO) cells having enhanced growth characteristics, said method comprising: (a) subjecting a starting population of CHO cells to one or more selection cycles comprising selective conditions; wherein said selective conditions comprise incubating said cells in a bioreactor in which less than 70% of said starting population of cells remain viable, with the proviso that said selective conditions do not comprise contacting said cells with a culture medium containing exogenously added ammonium; (b) obtaining one or more CHO cells that remain viable under said selective conditions; wherein said cells obtained from said one or more selection cycles exhibit all integral cell area (ICA) that is at least 25% greater than the corresponding ICA of said starting population of cells when said cells obtained from said one or more selection cycles and said starting population of cells are grown under the same culture conditions; and (c) inoculating said cells obtained in (b) into a bioreactor.