IL-15- and IL-2-induced STAT5 phosphorylation. (A) T cells from IM03 and HS01 were either untreated (untreat.) or stimulated with recombinant IL-15 (1 or 100 ng/mL) or IL-2 (100 IU/mL) for 30 minutes at 37°C. After stimulation, cells were lysed and phosphorylated STAT5a/b was detected by blotting the lysates with an antibody recognizing the STAT5a/b phosphorylated form (p-STAT5). Equivalent amounts of protein in the lysates were confirmed by blotting with anti-STAT5a/b (STAT5). (B) Means of pSTAT5/STAT5 ratio were obtained from 3 IM subjects (IM03, IM04, IM05) and 3 healthy subjects (HS01, HS02, HS05). Statistical analysis was performed using the Student t test and shows no significant differences between IM subjects and healthy subjects, independently of the stimuli used. NS indicates not significant.