Figure 1. CD39 is expressed in Tr1 cells.
(a) Entpd1 expression. (b) Flow cytometry analysis of CD39 expression in TH0, TH1, TH2, TH17, Tr1 cells and Foxp3+ Treg cells. Shown is CD39 expression and MFI data gated in cytokine (IFNγ, IL-4, IL-10 or IL-17) or Foxp3 positive T-cells. Total CD4+ T cells were used for the TH0 condition. (c) Nt5e expression. (d-e) CD39 (d) and CD73 (e) enzymatic activity in T cells. Quantification of AMP and adenosine expressed relative to ADP (bottom panel in d) and inosine (bottom panel in e), respectively. (f) AHR (blue; XRE-1, XRE-2 amd XRE-3) and STAT3 (green; SRE) binding sites in the Entpd1 promoter. (g) ChIP analysis of the interaction of AHR and STAT3 in the Entpd1 promoter. (h) Luciferase activity in HEK293 cells transfected with an Entpd1 luciferase reporter, alone (Control) or with a construct encoding constitutively activated STAT3 (Stat3c) or Ahr, separately or together (Ahr + Stat3c). (i) Expression of Entpd1 in T cells from WT, CD39-(Entpd1−/−) or STAT3-(Stat3−/−) deficient or Ahrmut mice after 72 h activation. (j) CD39 expression in Tr1 cells differentiated from Stat3−/− and Ahrmut mice analyzed by flow cytometry. Cells were gated in the CD4+Foxp3− population and the percentage of IL-10+CD39+ cells is shown. *P < 0.05; **P < 0.01; ***P < 0.001. Data are representative (b, d and e) or are the mean ± SEM (a-i) of three independent experiments. AU, arbitrary units.