Characterization of apoptosis induced by sorbitol: a unique system for the detection of antiapoptotic activities of viruses.

The treatment of HEp-2 cells with sorbitol induced massive apoptosis rapidly. This method for inducing apoptosis is very useful to detect antiapoptotic activity of viruses as well as viral genes. Commitment to death occurred immediately upon incubation with sorbitol, even in the presence of pancaspase inhibitor, Z-VAD-FMK. Apoptosis is also induced by other polyhydric alcohols with more than four hydroxyl groups, but not induced by glycerol or ethylene glycol. Sorbitol treatment on ice did not induce apoptosis either. These results suggest that this induction of apoptosis does not result simply from high osmotic pressure but probably by the interaction of solutes through their physical nature (such as hydrophobicity) with the plasma membrane of the cells.