NAIVE (CD45RA(-LYMPHOCYTES ARE MORE SENSITIVE TO OXIDATIVE STRESS-INDUCED SIGNALS THAN MEMORY (CD45RO(+)) CELLS()) T)

Formation of reactive oxygen intermediates (ROI) after oxidative stres s has been shown to be an activation signal for T lymphocytes, e.g., e xpression of IL-2 and its receptor are induced. These ROI-induced effe cts can, to a large extent, be attributed to the activation of the tra nscription factor NF-kappa B. Now we have examined whether naive and m emory T lymphocytes differ in their sensitivity to ROI-mediated signal s, When CD45RA(+) (naive) and CD45RO(+) (memory) T lymphocytes were di rectly stimulated with H2O2, NF-kappa B nuclear translocation was stro nger in naive cells than in memory cells and it could be induced with lower doses, The composition of the induced nuclear NF-kappa B (levels of p50 and RelA proteins) was similar in these cell types. The magnit ude and kinetics of intracellular ROI were similar, suggesting that th ere were no differences in ROI-forming mechanisms or antioxidative cap acities. The probable regulatory point was the cytoplasmic I kappa B i nhibitor: in CD45RA(+) cells, H2O2 caused a more profound depression i n the levels of I kappa B alpha, These findings indicate that T cells representing different activation and/or differentiation stages can be differentially responsive to ROI-mediated signals. (C) 1996 Academic Press, Inc.