Figure 1: IL-21 promotes the differentiation of CD4+ T cells that produce IL-22 but not IL-17.

Naïve WT CD4+ T cells were stimulated in vitro with antibodies to CD3 and CD28 in the presence of different cytokines as indicated. (a,b) Effect of IL-21 in the production of IL-22 and IL-17 measured by ELISA in culture supernatants (a) and qPCR (b). (c) Effect of IL-21 on the expression of il21. (e) Effect of IL-21 on the expression of il6r, il21r and il23r. (d) Relationship between cell division and IL-22 expression in CD4+ T cells. Carboxyfluorescein succinimidyl ester-labelled naïve CD4+ T cells were activated in the presence of IL-21 and the production of IL-22 was analysed by intracellular staining. The data are shown as the mean fluorescence intensity (MFI) for IL-22 for each division cycle. (e) Effects of IL-21 on the expression of il6r, il21r and il23r. (f–h) Synergistic effects of IL-21 and IL-23 on IL-22 (f) and IL-17 (g) cytokine and il21 expression (h). (i) Effect of IL-21 on il1r expression. (j–l) Synergistic effects of IL-21 and IL-1β on IL-22 (j), Il17a (k) and il21 (l) expression. mRNA expression is shown relative to gapdh. Results are representative of 3–5 independent experiments. *P<0.05, **P<0.01 and ***P<0.001 (one-way ANOVA).