(a) Experimental design for TCR experienced effector-like CD4+ T cells (TEXP). CD4+ TN cells were activated with anti-CD3/CD28 (1 μgr/ml and 5 μgr/ml, respectively) for 3 days after 2 days rest in normal media (RPMI). (b) Representative plot of STAT1 and STAT3 activity of CD4+ TEXP cells exposed to IL-6 (20ng/ml) for 30 minutes (n=3). (c) Analysis of pY-STAT1 and pY-STAT3 (MFI) in CD4+ TN cells (Day 1; n=3) versus CD4+ TEXP cells (Day 5; n=4) derived from WT and IL6ra −/− mice in response to IL-6 (20 ng/ml), HDS (30.74ng/mL; equimolar concentration equivalent to 20 ng/ml IL-6) or IL-27 (20 ng/ml) for 30 minutes as indicated. (d) Mean fluorescence intensity (MFI) for pY-STAT1 in CD4+ TN, TCM, TEM and TEff cells after 20 ng/ml of IL-6, IL-7 or IL-10 stimulation for 30min (n=3). **** P<0.0001, *** P<0.001, ** P<0.01, * P<0.05 (One-way ANOVA with Tukey multiple comparison test (c,d). Data are shown as mean ± s.e.m).