(A) Phenotypic and intracellular cytokine analysis of CNS-infiltrating cells in the brain and spinal cord of WT mice before and after EAE onset. Intracellular IL-17 and IFN-γ production by CD4⁺ CNS-infiltrating cells isolated from PLP-immunized SJL mice immediately following ex vivo stimulation with PMA/ionomycin for 4 hours prior to analysis. Data are representative of at least 5 independent experiments. (B) Average clinical score of mice (n ≥ 5) treated with 1 mg of indicated mAbs injected at day –1 and day 6 of immunization. Data are representative of at least 3 experiments. (C) Filled circles represent peak severity of clinical disease for individual mice of the indicated antibody treatment group. Data for the anti–IFN-γ treatment group are compiled from 3 separate experiments whereas data from the anti–IL-23p19 and anti–IL-17 groups are from at least 5 experiments. (D) Mice were treated with anti–IL-23p19 or anti–IFN-γ at day –1 and day 6 of immunization. Serum was prepared for IL-17 ELISA 2 days before expected onset. The limit of detection for serum IL-17 is 10 pg/ml. Results shown are averages of 5 mice per treatment group ± SEM and are representative of 2 experiments. (E) Routine H&E histology of spinal cords from antibody-treated mice taken at peak disease. Representative micrograph of anti–IL-23p19 treated mice shows no inflammation in the white matter of the CNS. Isotype control mAb–, anti–IL-17–, and anti–IFN-γ–treated mice show intense infiltration of inflammatory cells in the lumbar region of the spinal cord.