AGE-ASSOCIATED DECLINE IN IL-2 AND IL-12 INDUCTION OF LAK CELL-ACTIVITY OF HUMAN PBMC SAMPLES

Previously we reported that young and elderly natural killer (NK) cell activity against the standard NK sensitive K562 cell line can be augm ented to the same degree by IL-2 and IFN-alpha. We have extended these studies to include IL-12. Similar to IL-2 and IFN-alpha, IL-12 can en hance NK cytotoxicity to the same degree in both young and elderly sam ples over a wide range of doses and incubation times when K562 cells a re used as targets. However, in contrast to our findings with the NK s ystem, we have observed that induction of lymphokine activated killer (LAK) cell activity, as defined by the ability of peripheral blood mon onuclear cells (PBMC) samples to lyse the normally NK resistant Daudi cell line, was significantly decreased in the elderly samples compared to young samples. Comparable age-associated differences were observed in LAK activity after induction with IL-2, IL-12, and IFN-alpha at va rying doses and incubation times. We hypothesize an age-associated def iciency either in the mechanism of LAK induction or in target cell rec ognition.