CD28-mediated activation in CD45RA+ and CD45RO+ T cells: enhanced levels of reactive oxygen intermediates and c-Rel nuclear translocation in CD45RA+ cells. 
We have analyzed the effect of complete T cell activation (anti-CD3 plus anti-CD28) on the activation of NF-kappaB in CD45RA+ (naive) and CD45RO+ (memory/effector) T cells.  Long exposure (24 h) induced stronger NF-kappaB DNA binding in CD45RA+ cells than in CD45RO+ cells.  Analysis of the nuclear c-Rel protein indicated that after anti-CD3+anti-CD28 stimulation the level of c-Rel was higher in CD45RA+ cells.  Analysis of the cytoplasmic inhibitor IkappaBalpha indicated that anti-CD3+anti-CD28 stimulation induced a long-lasting degradation in CD45RA+ cells but in CD45RO+ cells the degradation process was more rapid.  Because the CD28 costimulus is known to induce the production of reactive oxygen intermediates (ROIs), the intracellular ROI levels in CD45RA+ and CD45RO+ cells were compared by flow cytometry.  ROIs were produced in both cell types, but more strongly in CD45RA+ cells.  The data presented in this study further emphasize the differences between CD45RA+ and CD45RO+ T lymphocytes in ROI-dependent signaling pathways.