SHP-1 negatively regulates IL-6–mediated Th17 development. (A) Representative IL-6 dose-response assay. CD4⁺ T cells from +/+ and me/+ C57BL/6 mice that were cultured under Th17-inducing with the indicated IL-6 concentrations followed by intracellular staining for IFN-γ and IL-17. Profiles show CD4⁺-gated population. (B) Relative Th17 T-cell generation from IL-6 dose-response assays presented in panel A. Percentages of maximal Th17 cells generated in cultures (maximum % Th17 cells: 37% +/+, 40% me/+) were set to 100% to determine EC₅₀. EC₅₀ values were calculated as: +/+ cells 1.0 ng/mL IL-6 (n = 4) and me/+ cells 0.25 ng/mL IL-6 (n = 7; P = .001). (C) IL-6R surface expression of splenic +/+, me/+, or me/me CD4⁺ T cells. Data are representative of 2 or 3 independent experiments with multiple mice for each genotype per experiment.