The expression of IL-17A, IL-17F and IL-22 in neutrophils is selectively induced by IL-23. (a) Primary neutrophils freshly isolated from the bone marrow of C57BL/6 mice were treated with various cytokines and LPS for 24 h. IL-17A, IL-17F and IL-22 mRNA expression levels were determined by real-time PCR. (b) Quantitative PCR analysis of IL-17A, IL-17F and IL-22 mRNA expression in neutrophils treated with IL-23 (50 ng/ml) for different times. (c) mRNA expression levels of IL-17A, IL-17F and IL-22 in primary neutrophils treated with different concentrations of IL-23 for 12 h were determined by real-time PCR. (d) mRNA expression levels of IL-17A, IL-17F and IL-22 in sorted CD11b+Ly6G+ neutrophils treated with IL-23 (0–50 ng/ml) for 12 h were determined by real-time PCR. (e) The protein levels of IL-17A in the culture medium of sorted CD11b+Ly6G+ neutrophils treated with IL-23 (50 ng/ml) for different times were determined by ELISA assays. The protein expression of IL-17A in neutrophils treated with 50 ng/ml IL-23 for 24 h was determined by flow cytometry (f) and confocal microscopy (g). Data are shown as the mean±s.d. (N=3), representing one of three independent experiments. *P<0.05, **P<0.01 and ***P<0.001 compared with control group. Data were analyzed by Mann–Whitney U-test for two group comparisons or one-way ANOVA analysis for multi-group comparisons using SPSS software. LPS, lipopolysaccharide.