Evidence for lowered induction of nuclear factor kappa B in activated human T lymphocytes during aging. Transcription factor NF kappa B (nuclear factor kappa B) is induced in T lymphocytes from young individuals following activation with a variety of stimuli including anti-CD3, phorbol myristate acetate (PMA), and tumor necrosis factor-alpha (TNF-alpha). In contrast, activated T lymphocytes from older individuals show a significant reduction in the induction of NF kappa B in response to the same stimuli. The age-related decline in induction of NF kappa B could not be attributed to alteration in the composition of subunits, p50 and p65 were found to be the predominant subunits of induced NF kappa B in T cells from young as well as elderly donors. Furthermore, similar levels of NF kappa B were found in the cytosols of unactivated T cells from both young and elderly donors suggesting that precursor levels of NF kappa B remain unaltered during aging. These results suggest that an age-associated decline in the induction of NF kappa B in activated T cells from elderly individuals may be attributable to altered regulation of the inhibitor, I kappa B, and may play an important role in immune dysregulation accompanying aging.