Trans-active factors controlling the IL-2 gene in adult human T-cell subsets.

IL-2 secretion in total or subsets of PHA/PMA-stimulated PBMC-derived human T-lymphocytes was monitored and found to be largely due to CD4(+)CD8(-) cells. The presence and functional state of transcription factors (TF) was assessed by protein-DNA interaction assays and functional transactivation experiments in the Xenopts oocyte system, modulating IL-2 transcription by injection of proteins. The results reveal that CD4(+)CD8(-) cells contain both, functional silencer in their resting, and positive TF in their activated states while the CD4(+)CD8(-) group contains only non-functional positive TF. This demonstrates that the on/off switch of IL-2 transcription is based on the same mechanism in primary T-lymphocytes of mouse spleen and in peripheral human CD4(+)CD8(-) cells.