Figure 8: Adiponectin suppresses IL-17 production from human CD4- and CD8-positive T cells.

(a) Messenger RNAs of subcutaneous fat (left panel) and skin (middle panel) tissue from psoriasis patients (n=26) and healthy controls (n=12) were extracted and examined for adiponectin level by quantitative (q)PCR. Data are mean±s.e. and analysed by Welch’s t-test. (b) Correlation of adiponectin level in psoriasis patients between subcutaneous fat and skin tissue is shown in the right panel. (c) Human CD4 and CD8-positive T cells were sorted and were analysed for the expression of adiponectin receptors, AdipoR1 and AdipoR2. (d) PBMCs were obtained from human whole blood, and were pretreated with indicated concentrations of adiponectin for 1 h, followed by treatment with plate-bound anti-CD3(5 μg ml⁻¹), soluble anri-CD28 (1 μg ml⁻¹) and IL-23 (0 and 25 ng ml⁻¹) for another 7 days. The supernatant IL-17 levels were determined using the IL-17 ELISA kit. Data are mean±s.e. (n=4) and are representative of two independent experiments. Data are analysed by one-way analysis of variance with Dunnett’s multiple comparison test. (e) Human PBMCs were treated as mentioned above for 5 days, stimulated with PMA and ionomycin and were stained with antibodies specific for IL-17A as well as CD4 and CD8 cell surface markers, followed by flow cytometric analysis. Data are representative of three independent experiments. (f) Graph shows the percentage of IL-17-positive cells among CD4- or CD8-positive T cells (n=3: IL-23 0 ng ml⁻¹, n=6: IL-23 25 ng ml⁻¹). Data are analysed by Welch’s t-test.