IL-2-mediated cell cycle progression and inhibition of apoptosis does not require NF-kappa B or activating protein-1 activation in primary human T cells

The IL-2 growth hormone is the major growth factor of activated T lymphocyt es during a developing immune response. IL-2 is required not only for cell cycle progression hut also to protect Ag-activated T cells from programmed cell death, In several cell types, activation of NF-kappa B and/or activati ng protein-1 (AP-1) has been demonstrated to he extremely important in bloc king apoptosis, To determine whether either or both of these transcription factors are involved in cell survival or cell cycle progression in response to IL-2, primary human T cells responsive to the growth factor were analyz ed for NF-kappa B and AP-1 activation. The current study clearly demonstrat es that IL-2 does not induce I kappa B alpha degradation or NF-kappa B acti vation in primary human T cells that respond to IL-2 by entering the cell c ycle and avoiding apoptosis, Similarly, IL-2 neither activates JNK nor incr eases AP-1 binding activity to a consensus o-tetradecanoylphorbol 13-acetat e (TPA) response element. On the other hand, the growth factor does induce the activation of STAT3 and STAT5 in these cells, as has been previously de monstrated, These data show that neither NF-kappa B nor AP-1 activation is required for IL-2-mediated survival or cell cycle progression in activated primary human T cells.