A) Within whole plated splenocytes, B6 and NOD Ly49+ CD8 Tregs phosphorylate STAT5 at Y694 to the same extent when exposed ex vivo to increasing concentrations of the IL-15C superagonist for 30 minutes. To account for the relatively small cell population analyzed, a minimum of 150 Ly49+ CD8 Treg events were captured, from which the MFI of pSTAT5Y694 was calculated. Data represent one experiment, repeated twice with similar results, which includes N=3 B6 mice and N=3 NOD mice. B) B6 and NOD Ly49+ CD8 Tregs phosphorylate STAT5 with similar time kinetics when exposed ex vivo to either 100, 1000, and 10000pM of IL-15C. Data represent one experiment, repeated twice with similar results, which includes N=3 B6 mice and N=3 NOD mice. Of note, NOD CD8 Tregs demonstrate statistically lower pSTAT5 levels 30 and 60 minutes after stimulation with the maximal 10000pM concentration of IL-15C (right panel). C) When exposed i.v. to 1ug of IL-15C for 60 minutes (calculated to reach 10000pM in a 2mL blood volume), both B6 and NOD Ly49+ CD8 Tregs increase pSTAT5 levels 15-times over animals injected with saline as a control. Data represent one experiment which includes N=3 B6 mice and N=3 NOD mice. *p<0.05, **p<0.01, ***p<0.005, ns = non-significant by two-way ANOVA followed by Bonferroni post-test.