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‐κB in CD45RA + (naive) and CD45RO + (memory/effector) T cells. Long exposure (24 h) induced stronger NF‐κB 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 IκBα 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. J. Leukoc. Biol . 63: 775–780; 1998.