Induction of metabolic markers correlates with IL-7–induced cell-cycle progression of CD4⁺ RTEs. CD4⁺ RTEs were cultured for 120 hours in the presence of rIL-7 doses ranging from 0.01 to 100 ng/mL (A). Alternatively, the time during which cells were exposed to rIL-7 (10 ng/mL) during the 120-hour incubation was varied, ranging from 0 hours to 120 hours (B). Surface expression of the Glut-1 glucose transporter was assessed using an EGFP-H_RBD fusion protein that specifically binds Glut-1,²⁶  whereas expression of the CD71 transferrin receptor was monitored with a fluorochrome-coupled mAb. Histograms depicting fluorescence (open histograms) relative to control staining (filled histograms) are shown. FSC/side scatter (SSC) profiles, a measure of blast formation, are also shown for each culture condition, and the live cell gates used for the above analyses are shown in each plot. Data are representative of results obtained in 4 independent experiments.