(A) IL-27 inhibits adoptive transfer of EAE in IFNAR^–/– mice. Spleen and lymph node cells isolated from immunized IFNAR^–/– mice were restimulated in vitro with MOG peptide in the presence of IL-27 or PBS for 72 hours. 3 × 10⁷ cells were transferred into IFNAR^–/– naive recipient mice via tail-vein injection (5 mice per group). (B) IFN-β–mediated IL-27 production inhibits adoptive transfer EAE in IFNAR^–/– mice. Spleen and lymph node cells isolated from immunized IFNAR^–/– mice were restimulated in vitro with MOG peptide in the presence of CM from IFN-treated macrophages with or without anti–IL-27 antibody. After 72 hours, 3 × 10⁷ cells were transferred into naive IFNAR^–/–recipient mice via tail-vein injection (5 mice per group). (C) IL-27 inhibits EAE development in WT mice. WT mice (n = 5) were immunized with MOG peptide emulsified in CFA. Recombinant carrier-free mouse IL-27 (0.25 μg in 100 μl PBS) was administered by s.c. injection to immunized WT mice every other day from day 2 until day 20. (D) Splenocytes from IL-27–treated WT mice represented in C were restimulated in vitro with MOG peptides for 72 hours, and IL-17 production was measured. (E) IL-27 treatment reverses the phenotype of EAE in IFNAR^–/– mice. Recombinant mouse IL-27 was administered by s.c. injection to immunized IFNAR^–/– mice (n = 5) every other day from day 2 until day 20. (F) Splenocytes from IL-27–treated IFNAR^–/– mice represented in E were restimulated in vitro with MOG peptides for 72 hours, and IL-17 production was measured.