A monoclonal antibody which recognizes a glycosaminoglycan epitope in bothdermatan sulfate and chondroitin sulfate proteoglycans of human skin

Studies have been initiated to identify various cell surface and matrix com ponents of normal human skin through the production and characterization of murine monoclonal antibodies. One such antibody, termed PG-4, identifies b oth cell surface and matrix antigens in extracts of human foetal and adult skin as the dermatan sulfate proteoglycans, decorin and biglycan, and the c hondroitin sulfate proteoglycan versican. Treatment of proteoglycans with c hondroitinases completely abolishes immunoreactivity for all of these antig ens which suggests that the epitope resides within their glycosaminoglycan chains. Further evidence for the carbohydrate nature of the epitope derives from competition studies where protein-free chondroitin sulfate chains fro m shark cartilage react strongly; however, chondroitin sulfate chains from bovine tracheal cartilage fail to exhibit a significant reactivity, an indi cation that the epitope, although present in some chondroitin sulfate chain s, does not consist of random chondroitin 4- or 6-sulfate disaccharides. Th e presence of the epitope on dermatan sulfate chains and on decorin was als o demonstrated using competition assays. Thus, PG-4 belongs to a class of a ntibodies that recognize native epitopes located within glycosaminoglycan c hains. It differs from previously described antibodies in this class in tha t it identifies both chondroitin sulfate and dermatan sulfate proteoglycans . These characteristics make PG-4 a useful monoclonal antibody probe to ide ntify the total population of proteoglycans in human skin.