Fig. 4: Blimp-1 and c-Maf are induced and jointly control IL-10 expression downstream of Notch/STAT3 signaling.

a High-throughput microfluidic real-time PCR for indicated genes of FACS-purified Th1, Th2, Th17 and Th1/17 co-stimulated w/ or w/o DLL4/Cyt (Cyt = IFN-α/IL-6/IL-21) for 24 h. Fold change (DLL4/Cyt vs. w/o) is shown. Data are mean values from six different donors from two different experiments. b Expression of Blimp-1 and c-Maf by FACS-isolated effector memory CD4⁺ T cells after cultivation and co-stimulation w/ or w/o DLL4/Cyt (Cyt = IFN-α/IL-6/IL-21) for 48 h. Representative histograms (left) and quantification of gMFI of Blimp-1 or c-Maf⁺ cells (right). c Quantification of IL-10⁺ cells among Blimp-1^+/− or c-Maf^+/− cells. d Quantification of IL-10⁺ cells among Blimp-1⁻c-Maf⁻, Blimp-1⁺c-Maf⁻, Blimp-1⁻c-Maf⁺ and Blimp-1⁺c-Maf⁺ cells. e, f FACS-isolated Th1, Th2, Th17 and Th1/17 cells were co-stimulated with DLL4/Cyt (Cyt = IFN-α/IL-6/IL-21) and treated with siRNA against c-Maf (siMAF) (e) or Blimp-1 (siPRDM1) (f) and control siRNA (siCtrl). Quantification of IL-10 production as measured by ELISA in cell culture supernatant. Each dot represents one healthy donor (n = 12–22). Two-tailed Wilcoxon and paired t tests were performed (**P < 0.01; ***P < 0.001) to assess significance. Data are cumulative from up to five independent experiments.