Experimental allergic encephalomyelitis: serum immunoglobulin binds to myelin and oligodendrocytes in cultured tissue: ultrastructural-immunoperoxidase observations
Johnson, A.B.; Raine, C.S.; Bornstein, M.B.
Laboratory Investigation; a Journal of Technical Methods and Pathology 40(5): 568-575
1979
ISSN/ISBN: 0023-6837 PMID: 374865 Document Number: 153057
The ultrastructural binding sites of immunoglobulin CNS tissue. Cultures were incubated 1 h with rabbit antiwhite matter serum, fixed and exposed to an anti-immunoglobulin-peroxidase conjugate. Within the explant, peroxidase reaction product (indicating bound Ig) was present on the outer plasmalemma of oligodendroglial processes associated with myelinated axons, in the external mesaxon and at the intraperiod line of myelin sheaths. The myelin was of the previously described, wide spaced configuration produced by heated EAE serum. On the explant surface, some cells with immunostaining around the entire plasmalemma were identified as oligodendroglia by the presence of wide spaced myelin where newly formed, interdigitating cytoplasmic infoldings abutted. The plasmalemma of many infoldings was thickened. These changes mimicked the more extensive aberrant myelinogenesis around oligodendrocytes noted previously after longer exposures to heated EAE serum. EAE serum apparently contains Ig that binds to antigen, or antigens, on the outer surface of oligodendrocytes and at the intraperiod line of myelin. In the presence of C, this Ig probably mediates the demyelinating and myelination-inhibiting activities of EAE serum on CNS cultures. Its binding in the area of the intraperiod line suggests that its presence may be causally related to the increase in width and doubling of the linear components of this myelin layer produced by heated EAE serum. Its binding to oligodendrocytic processes associated with myelin sheaths, in conjuction with the absence of demonstrable binding to other portions of oligodendrocytes within explants, suggests that there may be regional specialization of the oligodendroglial plasmalemma. Its binding to the plasmalemma of surface oligodendroglia forming aberrant myelin raises the possibility that under normal conditions, attachment of some compound to the oligodendrocyte plasmalemma may trigger myelin formation.