AGED MURINE T-LYMPHOCYTES ARE MORE RESISTANT TO OXIDATIVE DAMAGE DUE TO THE PREDOMINANCE OF THE CELLS POSSESSING THE MEMORY PHENOTYPE

Glutathione (GSH) is tire most important cytosolic antioxidant. Since GSH levels are decreased with age, we hypothesized that T-lymphocytes from old mice would be more sensitive to oxidative stress. T-lymphocyt es from young and old mice were exposed to hypoxanthine/xanthine oxida se, and lymphocyte viability, proliferation, GSN content, and calcium signaling were measured. Before exposure, proliferation of T-lymphocyt es from young mice was greater than that of old-following exposure, th e converse was true. This was in spite of the fact that old mice had l ower total GSH levels and greater levels of glutathione disulfide. Aft er oxidative challenge, intracellular calcium responses to anti-CD3 we re decreased in naive T-lymphocytes from all mice, while memory lympho cytes were less affected. Higher proportions of memory lymphocytes in old mice resulted in their greater overall preservation of lymphocyte function following oxidative injury, contrary to expectations that low er lymphocyte GSH content with age would increase susceptibility to ox idative stress.