Detection of epitopes in glycosaminoglycans immobilized on hydrophobic membranes
Scandinavian Journal of Clinical and Laboratory Investigation. Supplementum
S Björnsson
Abstract
Glycosaminoglycans (GAGs) are linear carbohydrate polymers expressed on all cell surfaces, and bind growth factors that recognize specific disaccharide sequences. Such sequences in the GAG chain are not genetically determined but may be assembled by the cell in response to environmental changes. GAGs are strongly hydrophilic and negatively charged molecules that do not bind well to either polystyrene surfaces or to hydrophobic blotting membranes. Cationic detergents were used to derivatize hydrophobic membranes to become hydrophilic and positively charged. Binding of GAGs to derivatized membranes was optimized regarding pH and ionic strength. Five different monoclonal antibodies (Mab) were used to detect sequence epitopes in immobilized GAGs. Parallel samples were stained with Alcian Blue and the staining intensities were quantitated by scanning and densitometry. By calculating the ratio between the antibody staining (epitope) and Alcian Blue staining (mass), the epitope density, i.e. the number of repetitive epitopes per mass, is obtained. The epitope density with each antibody was different with different GAGs. Some epitopes were common in GAG, i.e. highly repetitive epitopes. Some epitopes were rare and possibly expressed on...Continue Reading