IL-17 but not IL-17F is required for the initiation of EAE. (A) EAE was induced in IL-17F KO, IL-17 KO, and WT control mice. Data shown are a combination of two independent experiments (n = 10 for each group). (B) Infiltrates in the CNS from the EAE mice were isolated after perfusion on day 12 after the second immunization, and CD4⁺ and CD11b⁺ cells were assessed by FACS. Horizontal bars indicate mean values. Data shown represent two independent experiments with similar results. (C) Chemokine expression in the CNS from the EAE mice was measured by real-time RT-PCR. (D) Splenocytes from the EAE mice were stimulated with MOG peptide, and cytokine expression levels were measured by ELISA. Data shown represent two independent experiments with similar results. (E) WT, IL-17 KO, and IL-17F KO mice were immunized with MOG/CFA and administered with pertussis toxin on the next day. 7 d after immunization, the mice were killed and IL-17–, IL-17F–, and IFN-γ–producing cells in the spleen and draining lymph nodes were analyzed by intracellular staining. Data shown are gated on CD4⁺ cells and are averaged from three to four mice in each group. Results are mean ± SD. *, P < 0.05; and **, P < 0.005 using the Student's t test. n.s., not significant.