THE EPITOPE(S) RECOGNIZED BY HNK-1 ANTIBODY AND IGM PARAPROTEIN IN NEUROPATHY IS PRESENT ON SEVERAL N-LINKED OLIGOSACCHARIDE STRUCTURES ON HUMAN P0 AND MYELIN-ASSOCIATED GLYCOPROTEIN

Abstract: The mouse monoclonal antibody HNK‐1 and the human monoclonal IgM antibody present in patients with polyneuropathy both recognize carbohydrate epitope(s) on human myelin‐associated glycoprotein and P0. In the present study, the oligosaccharide structures that bear the antibody epitope(s) were investigated. The extracellular derivative of myelin‐associated glycoprotein (dMAG) was purified by immunoaffinity chromatography. P0 was electroeluted from gel slices. Western blot analysis of whole glycoproteins demonstrated that the epitopes for HNK‐1 and the human monoclonal IgM antibody were different. The glycopeptides obtained by proteolysis of purified dMAG and P0 were separated and characterized by affinity chromatography on concanavalin A‐Sepharose. Both dMAG and P0 displayed heterogeneity in their oligosaccharide structures, i.e., they both contained mainly tri‐ and tetraantennary oligosaccharides (∼80%), although biantennary (10%) and high‐mannose and/or hybrid (10%) oligosaccharides were present. The human monoclonal IgM antibody epitope was present on all types of isolated oligosaccharide structures from either dMAG and P0. The HNK‐1 epitope was present on all types of oligosaccharide structures of dMAG, whereas it was present only on tri‐ and tetraantennary structures of P0. Copyright © 1990, Wiley Blackwell. All rights reserved