Effects of aging on the in vitro response of human lymphocytes to interleukin-2.

Effects of aging on the in vitro responses of human peripheral blood lymphocytes (PBL) to interleukin-2 (IL-2, T-cell growth factor) were studied. Aged PBL showed a significantly lower response to phytohemagglutinin (PHA) than young PBL. On the other hand, proliferative responses to exogenous IL-2 showed by aged PBL were found to be in same extent as those of young PBL. In addition, cultured lymphoid cells propagated in IL-2 (CLC-IL-2) derived from both young and aged PBL showed a strong cytotoxic reactivity against the natural killer (NK) sensitive target K562.