MYELIN OLIGODENDROCYTE GLYCOPROTEIN IS A MEMBER OF A SUBSET OF THE IMMUNOGLOBULIN SUPERFAMILY ENCODED WITHIN THE MAJOR HISTOCOMPATIBILITY COMPLEX

Myelin/oligodendrocyte glycoprotein (MOG) is found on the surface of m yelinating oligodendrocytes and external lamellae of myelin sheaths in the central nervous system, and it is a target antigen in experimenta l autoimmune encephalomyelitis and multiple sclerosis. We have isolate d bovine, mouse, and rat MOG cDNA clones and shown that the developmen tal pattern of MOG expression in the rat central nervous system coinci des with the late stages of myelination. The amino-terminal, extracell ular domain of MOG has characteristics of an immunoglobulin variable d omain and is 46% and 41 % identical with the amino terminus of bovine butyrophilin (expressed in the lactating mammary gland) and B-G antige ns of the chicken major histocompatibility complex (MHC), respectively ; these proteins thus form a subset of the immunoglobulin superfamily. The homology between MOG and B-G extends beyond their structure and g enetic mapping to their ability to induce strong antibody responses an d has implications for the role of MOG in pathological, autoimmune con ditions. We colocalized the MOG and BT genes to the human MHC on chrom osome 6p21.3-p22. The mouse MOG gene was mapped to the homologous band C of chromosome 17, within the M region of the mouse MHC.