Ligand-induced apoptosis of mature T lymphocytes (propriocidal regulation) occurs at distinct stages of the cell cycle.

We previously demonstrated that mature T lymphocytes responding to either IL-2 or IL-4 undergo apoptosis upon T cell antigen receptor stimulation, and have termed this potential negative feedback pathway propriocidal regulation. Using cell cycle inhibitors, we now show that T cell growth lymphokines cause the entry of T cells into vulnerable stages of the cell cycle in which T cell receptor occupancy causes apoptosis.