IL2 and infection: To exclude unspecific activation of the U3R-driven eGFP reporter upon mitogenic stimulation of Jurkat T-cells and to select appropriate mitogens for infection experiments, the Jurkat–SMPU reporter clones 21 and 29 and the mixed clone of the clones 21, 29, 31, and 34 were either treated with the mitogen PMA (20 nM) in combination with the Ca2+ ionophore ionomycin (1 μM) or with the lectin PHA-P (2 μg/mL) together with IL-2 (25 U/mL) and compared to the respective solvent controls DMSO or PBS at one, two, five, or seven days post-treatment (Figure 4).