Activation-induced cell death

The death of T lymphocytes following their activation involves several sign al pathways that converge on a series of proteases, known as caspases, that degrade cellular proteins and activate a DNAse. Caspases are activated thr ough ligation of cell surface death receptors as well as via direct activat ion of downstream caspases, often through metabolic stress such as cytokine withdrawal or generation of oxygen radicals, that culminates in mitochondr ial dysfunction and release of the proapoptotic molecules, cytochrome c and Smac/DIABLO. The Bcl-2 family members serve to regulate the mitochondrial membrane integrity. Recent studies are now revealing the significant contri bution to the activation-induced cell death of cells by downstream caspases such as caspase-3 and Bcl-2-homology domain 3 (BH3)-only members of the Bc l-2 family.