Throughout their life span, T lymphocytes are confronted with diverse and often extreme
circumstances: they either are in a resting state or proliferate vigorously and find themselves
in lymphoid organs, blood stream, or peripheral tissues. Under all these conditions, their
survival depends on extracellular factors that counteract apoptotic cell death and sustain
metabolism. In the different phases of T cell life and throughout the antigen-dependent T cell
response, different cytokine receptors and costimulatory receptors provide the input to direct …