Brain contains HNK-1 immunoreactive O-glycans of the sulfoglucuronyl lactosamine series that terminate in 2-linked or 2,6-linked hexose (mannose).
The monoclonal antibody HNK-1 originally raised to an antigenic marker of natural killer cells also binds to selected regions in nervous tissue. The antigen is a carbohydrate that has attracted much interest as its expression is developmentally regulated in nervous tissue, and it is found, and proposed to be a ligand, on several of the adhesive glycoproteins of the nervous system. It is also expressed on glycolipids and proteoglycans, and is the target of monoclonal auto-antibodies that give rise to a demyelinating disease. The epitope, as characterized on glycolipids isolated from the nervous system, is expressed on 3-sulfated glucuronic acid joined by beta1-3-linkage to a neolacto backbone. Here we exploit the neoglycolipid technology, in conjunction with immunodetection and in situ liquid secondary ion mass spectrometry, to characterize HNK-1-positive oligosaccharide chains derived by reductive alkaline release from total brain glycopeptides. The immunoreactive oligosaccharides detected are tetra- to octasaccharides that are very minor components among a heterogeneous population, each representing less than 0.1% of the starting material. Their peripheral and backbone sequences resemble those of the HNK-1-positive glycolipids. An unexpected finding is that they terminate not with N-acetylgalactosaminitol but with hexitol (2-substituted and 2,6-disubstituted). In a tetrasaccharide investigated in the greatest detail, the hexitol is identified as 2-substituted mannitol.
Yuen
C T
CT
The Glycosciences Laboratory, Imperial College School of Medicine, Northwick Park Hospital, Harrow, Middlesex, HA1 3UJ, United Kingdom.
Chai
W
W
Loveless
R W
RW
Lawson
A M
AM
Margolis
R U
RU
Feizi
T
T
D000818:Animals; D000911:Antibodies, Monoclonal; D001923:Brain Chemistry; D018957:CD59 Antigens / Q000737:chemistry* / Q000276:immunology; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D008358:Mannose / Q000032:analysis*; D009844:Oligosaccharides / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry* / Q000276:immunology; D011817:Rabbits; D018629:Spectrometry, Mass, Secondary Ion
D000911:Antibodies, Monoclonal; D018957:CD59 Antigens; D009844:Oligosaccharides; D011134:Polysaccharides; D008358:Mannose