Fig. 3

Recombinant IL-38 proteins do not affect IL-36γ-induced IL-8 production in IL-36R HEK Blue and NHK cells. A. IL-36R HEK Blue and B. NHK cells were preincubated with recombinant human IL-38 variants (aa2-152 with C-terminal His tag; aa2-152; aa3-152; aa20-152 IL-38:Fc-KIH fusion protein) at indicated concentrations (10-3000 ng/ml, corresponding to 0.4–58.8 nM; see Table 1), before stimulation with IL-36γ (0.1 ng/ml or 10 ng/ml, respectively, corresponding to 0.006 or 0.6 nM) for 24 h. IL-8 production was assessed by ELISA in culture supernatants. Recombinant human IL-36Ra (10-1000 ng/ml, corresponding to 0.6–58.8 nM) was used as a positive control to inhibit IL-36γ. Recombinant human sIL-1Ra (1-1000 ng/ml, corresponding to 0.06–58.8 nM) was used as a negative control. Results are expressed in % of the IL-8 production observed with IL-36γ alone. Each dot represents the mean of 3 technical replicates in an independent experiment. Results are shown as individual values and mean ± SEM for 3 (A) or 4 (B) independent experiments. **p < 0.01, ***p < 0.001, ****p < 0.0001 vs. IL-36γ alone, as assessed by ANOVA, followed by Dunnett’s multiple comparisons test