Figure 4.

Nef potentiates IL-2 promoter activation. Cells grown 4 days in tetracycline-free medium were electroporated with an IL-2 promoter luciferase reporter plasmid and were kept either with (open bars) or without (dark bars) tetracycline. Forty-eight hours later, aliquots of cells from each group either were left untreated or were stimulated as indicated (with crosslinking for α-CD3) for fourteen hours before measuring luciferase activity. Fold activation represents the ratio of values in test sample vs. its uninduced/unstimulated control. Data are averages from representative duplicate experiment, with variability as error bar. Without stimulation, Nef had no effect (not shown).