Siponimod (BAF312; ADV638392161, Sigma-Aldrich) was suspended in 0.5% carboxymethylcellulose (CMC) medium viscosity (C4888, Sigma-Aldrich) and dosed adjusted to body weight (BW) with 3 mg/kg per day. This dosing was chosen because it has been shown to ameliorate EAE in rats, whereas a dose similar to that used in patients with MS (0.03 mg/kg BW) did not.21 (link) The vehicle alone, 0.5% CMC, was administered to a control group. In an attempt to prevent EAE (prevention paradigm), mice received the first dose at the age of 26 ± 2 days (n = 17 siponimod treated; n = 14 vehicle treated). For the evaluation of the therapeutic potential (treatment paradigm), mice were treated when reaching a clinical score of ≥3 (n = 7 siponimod treated; n = 8 vehicle treated). Considering the sex and the age when EAE started, animals were alternately assigned to treatment groups and received the respective agent daily via oral gavage. To minimize potential confounders, only mice of the same treatment group were held together in 1 cage. Mice were killed 30 days after the first application. For histologic reference at peak of disease, 5 mice were dissected when they reached a score of 3 without any further treatment.