Binding of Cytoplasmic Islet Cell Antibodies Is Blocked by Human Pancreatic Glycolipid Extracts

摘要: With biochemical and enzymatic treatment of frozen sections pancreas, we have previously shown that cytoplasmic islet cell antibodies (ICAs) react with carbohydrate determinants glycoconjugates. As a first step toward purifying these glycoconjugates, human pancreas tissue was extracted in mixture chloroform methanol, the glycolipids were obtained by effecting Folch partition. The protein pellet, lipid fraction, glycolipid fraction so assessed for their ability to block binding ICAs effect being quantitated photometer. Only extract could ICA binding, blocking dose dependent. Subfractionation hydrophobic interaction on C18 cartridges demonstrated activity resided bound eluted consistent autoantigen glycolipid. Furthermore, an anti-islet ganglioside monoclonal antibody, 3G5, be blocked extracts, whereas 4F2, unaffected. major gangliosides seen GM3 GD3 thin-layer chromatography (TLC). Fractions scraped from TLC plates tested pancreatic sections. Neither GM3- nor GD3-containing fractions binding; however, containing minor (including GM2) monosialoganglioside mobility potent inhibitor chloroform-methanol islets differentially express monosialogangliosides (especially GM2).