Distinct patterns of glia repair and remyelination in antibody‐mediated demyelination models of multiple sclerosis and neuromyelitis optica

Abstract Multiple sclerosis (MS) and neuromyelitis optica (NMO) are inflammatory demyelinating disorders of the central nervous system with evidence of antibody‐mediated pathology. Using ex vivo organotypic mouse cerebellar slice cultures, we have demonstrated that recombinant antibodies (rAbs) cloned from cerebrospinal fluid plasmablasts of MS and NMO patients target myelin‐ and astrocyte‐specific antigens to induce disease‐specific oligodendrocyte loss and myelin degradation. In this study, we examined glial cell responses and myelin integrity during recovery from disease‐specific antibody‐mediated injury. Following exposure to MS rAb and human complement (HC) in cerebellar explants, myelinating oligodendrocytes repopulated the demyelinated tissue and formed new myelin sheaths along axons. Remyelination was accompanied by pronounced microglial activation. In contrast, following treatment with NMO rAb and HC, there was rapid regeneration of astrocytes and pre‐myelinating oligodendrocytes but little formation of myelin sheaths on preserved axons. Deficient remyelination was associated with progressive axonal loss and the return of microglia to a resting state. Our results indicate that antibody‐mediated demyelination in MS and NMO show distinct capacities for recovery associated with differential injury to adjacent axons and variable activation of microglia. Remyelination was rapid in MS rAb plus HC‐induced demyelination. By contrast, oligodendrocyte maturation and remyelination failed following NMO rAb‐mediated injury despite the rapid restoration of astrocytes and preservation of axons in early lesions.