S100B KO mice are protected from EAE-induced paralysis. (A) Schematic representation of the study outline. Female S100B WT and S100B KO mice were induced with EAE by MOG_35–55 immunization and monitored until 30 days after EAE induction. (B) S100B gene and protein expression levels were determined by qReal-Time PCR and western blot, respectively. (C) Clinical score observations and (D) body weight were measured for both experimental groups, S100B WT and KO mice, for 30 days. Clinical score was given followed a 5-point scale, establishing a numeric value to the disease severity. The EAE index represents the AUC that was also calculated for each animal. (E) Representative images of spinal cord sections showing demyelinating lesions immunostained for mature oligodendrocytes (MBP) and counterstained for cell nuclei (DAPI). Scale bar: 200 µm for slices and 50 µm for insets. Magnification: 20× for slice and 40× for insets. Number of demyelinating lesions and respective area were detected. Unpaired Mann–Whitney t-test was used for statistical significance (*P < 0.05, **P < 0.01 and ***P < 0.001 versus S100B WT). (C–D) n = 4 animals for S100B WT, and n = 9 animals for S100B KO; (F–G) n = 3 animals for S100B WT and S100B KO.