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Myelin‐associated glycoprotein in multiple sclerosis lesions: A quantitative and qualitative analysis
Author(s) -
Möller Johanna R.,
Yanagisawa Katsuhiko,
Brady Roscoe O.,
Tourtellotte Wallace W.,
Quarles Richard H.
Publication year - 1987
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.410220405
Subject(s) - myelin associated glycoprotein , myelin , proteolipid protein 1 , white matter , multiple sclerosis , glycoprotein , polyclonal antibodies , immunostaining , blot , epitope , myelin basic protein , biology , microbiology and biotechnology , antibody , pathology , biochemistry , immunology , immunohistochemistry , central nervous system , medicine , endocrinology , magnetic resonance imaging , radiology , gene
Myelin‐associated glycoprotein (MAG), myelin basic protein (MBP), and proteolipid protein (PLP) were quantitated by immunoassays in nine plaque, inner periplaque, outer periplaque, and normal‐appearing white matter regions from brains of five multiple sclerosis patients and compared with the levels found in white matter samples of control subjects matched for age, postmortem time, and brain region. In plaque and inner periplaque regions, all three proteins were substantially reduced due to extensive myelin loss. In outer periplaque regions, MBP and PLP were close to control levels, but MAG was significantly reduced to a mean of 57% of control. All three proteins were close to control levels in the normal‐appearing white matter samples. MAG in the various regions was qualitatively examined on Western blots by binding of lectins and by immunostaining with polyclonal and monoclonal antibodies against carbohydrate and protein epitopes of MAG. Densitometric scanning of these blots did not reveal any qualitative differences in the oligosacharide or polypeptide moieties of MAG between samples from control subjects and those from multiple sclerosis patients. However, a high proportion of the MAG in the multiple sclerosis samples was often in the form of dMAG, a proteolytic derivative of MAG that is formed by a myelin‐associated, Ca 2+ ‐activated, neutral protease. The preferential loss of MAG at the periphery of multiple sclerosis plaques may be initiated by its proteolytic conversion to dMAG.