Post‐natal development of neuromuscular junctions in the avian iris

Multiple sclerosis (MS) is the most frequent chronic neurological disease. A]though its etiology remains obscure,both humoral and cellular abnormalities of the immunological system have been described. Their consequences are a destruction of the myelin sheath,but it is not yet clear wether the primary target is the myelin sheath or the oligodendrocyte. To test the hypothesis of an oligodendroglial target we have undertaken the study of the binding of IgG on oligodendrocytes in culture. IgG of MS cerebrospinalfluids (CSF) and IgG secreted in culture by B lymphocytes of MS CSF have been used. We have paid a special attention on a precise characterization of the IgG positive cells by a double labelling approach using specific gal~tosylceramide affinity purified antibodies. The bias due to putative Fc receptors on oligodendrocytes have been carefully studied and will be discussed in detail.