T-cell mean fluorescence intensity (MFI) in Rosa and Cags mice (n = 10) at various doxycycline plasma concentrations on day 13. Data points represent the mean GFP expression and mean plasma concentration measured for each of the 6 dose groups (from lowest to highest plasma doxycycline concentration achieved at doses of 25 µg/mL, 200 ppm, 150 µg/mL, 625 ppm, 467 µg/mL, and 2 mg/mL) in this study. Bars indicate 95% confidence intervals.