Fig. 7

MS rAb#49 (MS#49) binds to myelin and causes demyelination in presence of HC. Staining of mouse cerebellum with isotype control rAb (Iso) is negative (a) whereas MS #30 rAb staining (b) showed localization in cerebellar deep white matter (DWM) and myelinated tracks within the granule cell layer (GCL). Note the abrupt absence of staining at the molecular layer (ML). A similar staining pattern was observed with MS#49 rAb (c). All rAbs (green) were used at 20 μg/ml. Scale bar: 50 μm. MS#49 bound to oligodendrocyte processes and myelinated MAG+ axons in cultured mouse cerebellar slices (d–g). Live slices prepared from PLP-eGFP mouse pups were incubated with 20 μg/ml MS#49 rAb (red) then fixed and immunostained with anti-human secondary and MAG (blue). MS#49 live binding signals were co-localized with PLP-eGFP+ oligodendrocyte processes and MAG+ myelinated axons (stained with NF-H, arrows). Scale bar: 10 μm. MS#49 induced complement-dependent cytotoxicity to mature oligodendrocytes and demyelination. Confocal images of PLP-eGFP in slices treated with MS#49 −/+ HC for 48 h (h, i) and then fixed and stained with MBP (red) and NF-H (blue) antibodies (j, k). Scale bar: 100 μm. MS#49 + HC induced microglia activation with no effect on astrocytes. PLP-eGFP slices treated with MS#49 + HC for 48 h were fixed and stained with Iba1 (l) and GFAP (m). Scale bar: 50 μm. MS#49 treatment activates the complement pathway on oligodendrocyte processes (n–q). PLP-eGFP slices were treated with MS#49 + HC for 48 h and stained with MAC (red). Deposits of MAC were detected along PLP-eGFP+ oligodendrocyte processes and co-localized with MS#49 rAb (blue, arrows). Scale bar: 25 μm