Expression of Gadd153 in Sp2/0 stationary batch cultures. A) Stationary batch culture of Sp2/0 cells. Closed circles: viable cell density. Open circles: Percentage of viable cells in the culture. Data are expressed as the average ± standard deviation of 3 independent experiments. B) Immunoblot analysis of Gadd153 expression during batch culture (data representative of 3 independent experiments).