Structure of a glycolipid reacting with monoclonal IgM in neuropathy and with HNK-1

An acidic glycolipid antigen that reacts with monoclonal IgM in patients with demyelinating neuropathy and with the mouse monoclonal antibody, HNK-1, was purified from human peripheral nerves. This lipid sharing antigenic determinants with the myelin-associated glycoprotein was shown to be an unusual glucuronic acid-containing sulfated glycosphingolipid with five sugars, but without sialic acid. Mild acid methanolysis converted the GlcUA to its methyl ester, removed the acidic sulfate group and abolished the antigenicity. Results from chemical, enzymatic, infrared, and mass spectral analysis suggested the following structure with a sulfate in a position that remains to be determined: GlcUA beta 1----3Gal beta 1----4GlcNAc beta 1----3Gal beta 1----4Glc beta 1----1 ceramide.