Fig. 11. Time course of caspase 9 activation in TNF-stimulated C2VC and C2/AS cells. Cells were stimulated with TNF (30 ng/ml), and cytosolic fractions were isolated at varying times. Caspase 9 activity was measured using a fluorometric substrate. Values shown are means ± SE for three separate experiments. *, P < 0.05 and ++, P 0.01 compared with vector transfected cells by paired Students ttest.