Mn induces Th17 differentiation of donor T cells in a Dectin-2–dependent manner. (A-G) The 5 × 10⁴ T cells were cultured with 1 × 10⁵ 12 Gy-irradiated macrophages in the presence of 0.5 μg/mL of CD3 monoconal antibodies and 10 ng/mL of TGF-β with or without 100 μg/mL of Mn for 5 days. (A) Levels of cytokines in supernatant from 1 of 3 independent experiments are shown as means ± standard error.(SE) (B) Representative dot plots of flow cytometric analysis of intracellular IL-17A staining of CD4⁺ T cells after 5-day culture are shown. Frequencies (C) and numbers (D) of IL-17A⁺CD4⁺ Th17 cells from 1 of 3 independent experiments are shown as means ± SE. (E-G) Intracellular IL-17A staining of T cells cultured with WT or Dectin-2^−/− macrophages were performed. Representative dot plots (E) shows IL-17A production in CD4⁺ T cells after coculture with WT (top panels) or Dectin-2^−/− (bottom panels) macrophages in the presence or absence of Mn. Frequencies (F) and numbers (G) of IL-17A⁺CD4⁺ Th17 cells from 1 of 3 independent experiments are shown as means ± SE. *P < .05.