Impaired induction of EAE in mice treated with IL-2–JES6-1. EAE was induced on day 0 by immunization of MOG_35-55 in CFA. Mice were treated with combinations of 1 µg IL-2, 5 µg JES6-1, and 1 mg/kg rapamycin, as described (n = 8–10 per group). (A) Disease score of mice treated on days −3, −2, and −1 with PBS, IL-2, or IL-2–JES6-1. (B) Disease score of mice treated with PBS, IL-2, or IL-2–JES6-1 at the onset of symptoms (typically days 7, 8, and 9). (C) Disease score of mice treated with PBS, IL-2–JES6-1 (days 2, 3, and 4), rapamycin (days 2, 3, and 4), or IL-2–JES6-1 (days 2, 3, and 4) plus rapamycin (days 2, 3, and 4). The treatment groups in C were further analyzed in D and E. (D) The number of CD4⁺IL-17⁺ (triangles) and CD4⁺IFN-γ⁺ (diamonds) in the draining LNs and spinal cords of mice at day 12 after MOG immunization. For the draining LNs, the percentage of cytokine-producing CD4⁺cells for the four groups ranged from a mean of 1.5–2% for IL-17A⁺ cells and 2.5–3% for IFN-γ⁺ cells; for the spinal cord, the mean percentage of positive cells in the control group was 11% for IL-17A⁺ cells and 43% for IFN-γ⁺ cells; and in the rapamycin group the mean was 5% for IL-17A⁺ cells and 30% for IFN-γ⁺ cells (n = 8–9 per group). (E) T reg cells quantified as cell numbers (top) and percentages (bottom) of CD4⁺ T cells in the draining LNs and spinal cords of mice at days 7 and 12 after MOG immunization (n = 5 per group). Data are representative of two to three independent experiments. Data are means ± SEM (A–C). Symbols represent individual mice and horizontal bars represent means in D and E. #, mice euthanized for ethical reasons.