Dot immunobinding as a tool for the study of the CNS myelin antigen, M2

The unidentified antigen M2, which is the target of demyelinating antibodies in sera from guinea pigs immunized with brain tissue, was studied using a dot immunobinding assay. This method is particularly appropriate for studying the immunologic properties of insoluble brain components such as myelin, glycolipids and myelin proteins. M2 was found to be a component of central nervous system myelin and not peripheral myelin. It appeared at the time of myelination, was not cerebroside or GM1 ganglioside and did not cross-react with the major myelin proteins, i.e. proteolipid or basic protein. These observations confirm and extend previous studies using a complement fixation assay for M2. The antigen was shown to be partially solubilized by Brij 35 and this detergent can provide a starting point for attempts at purification.