Glycosaminoglycan chains of proteoglycans: approaches to the study of their structure and function

Monoclonal antibodies capable Of recognizing glycosaminoglycan (GAG) fine structures are likely to be of immense value in isolating and characterizing GAG chains with specific functional domains. We previously described the characterization of a monoclonal antibody directed against the chondroitin sulfate moiety of chick embryo fibroblast proteoglycan. This antibody is highly specific for GlcA(2S04)~1-3GalNAc(6-S04), the minor disaccharide unit occasionally found in some chondroitin sulfate chains. More recently, we have prepared a monoclonal antibody (HK-249) to the heparan sulfate moiety of EHS-tumor proteoglycan. This antibody recognizes a fine structure which is abundant in the tumor heparan sulfate but rare in heparan sulfate preparations purified from healthy mammalian tissues. Chemical parameters of various heparan sulfate preparations and their respective activities suggest that the exceedingly high concentration of non-)-sulfated GlcNS03 residues in the tumor heparan sulfate plays an important role. Many applications of anti-GAG monoclonal antibodies can be foreseen in both detecting and separating specific GAG subpopulations by virtue of their ability to recognize characteristic GAG fine structures or sequences.