Myelin-binding antibodies in vitro. Immunoperoxidase studies with experimental allergic encephalomyelitis, anti-galactocerebroside and multiple sclerosis sera

Abstract

To determine whether in vitro demyelinating activity of blood sera correlates with the presence of myelin-binding immunoglobulin, we studied sera from 7 rabbits with allergic encephalomyelitis induced with white matter homogenate (EAE), two with encephalomyelitis induced with myelin basic protein (MBP-EAE), two sensitized with galactocerebroside, and from 4 patients with multiple sclerosis (MS). Living, myelinated, organotypic cultures of fetal mouse spinal cord were incubated with serum, fixed, treated with peroxidase-conjugated anti-rabbit or anti-human immunoglobulins, and incubated with diaminobenzidine. Immuno-stained myelin, coursing across the cultures, was found with EAE and anti-galactocerebroside sera, and these sera had strong demyelinating activity. In addition, anti-galactocerebroside serum sometimes immuno-stained cell membrane of cells with elaborate branching processes, possibly oligodendrocytes. No immuno-stained myelin was found with MBP-EAE, MS or control sera. Of these, only MS serum had demyelinating activity. These results indicate that the demyelinating activity of animal sera is associated with a myelin-binding immunoglobulin, which in the presence of complement probably mediates demyelination. On the other hand, the demyelinating activity of MS serum does not appear to be associated with a myelin-binding immunoglobulin. Thus there are differences between the demyelinating activities of MS and EAE sera.