PGE₂ and IL-23 specifically enhance the production of IL-17 and some of the related cytokines by human PBMCs. (A) IL-17; (B) IFN-γ; (C) IL-1β; (D) CCL20/MIP-3α; (E) IL-22; (F) CXCL8/IL-8. PBMCs (1 × 10⁶) were activated by CD3 cross-linking and cultured for 7 days before harvesting of supernatants. PGE₂ (50 ng/mL) and IL-23 (10 ng/mL) were added at the beginning, and IL-2 (20 U/mL) was added after 48 hours of culture. IL-17, IFN-γ, and IL-1β were assessed by multiplex immunoassay, whereas CCL20/MIP-3α, IL-22, and CXCL8/IL-8 were assessed by ELISA. Box plots represent the 10th, 25th, 50th, 75th, and 90th percentiles of 11 distinct individual donors (except CXCL8/IL-8, n = 7). Circles represent outliers. *Significant differences (P < .01) compared with the nil culture condition by paired Student t test. Note that the IL-17 scale is logarithmic.