title: Identification of a sulfate-bearing molecule associated with HLA class II antigens.
abstract: The human Ia antigens (DR, DS, and SB), determined by genes contained within the HLA complex on chromosome 6, are glycoprotein heterodimers consisting of a Mr approximately equal to 34,000 alpha chain and a Mr approximately equal to 28,000 beta chain. As a result of studies exploring the possibility that alpha or beta (or both) might be sulfated, a unique component of the oligomeric Ia antigen complex was discovered. When anti-Ia immunoprecipitates from Nonidet P-40 lysates of [35S]sulfate-labeled lymphoid cells were analyzed by NaDodSO4/PAGE, a molecule of considerable size heterogeneity (Mr 40,000-70,000) was observed. This component was present in both anti-DR and anti-DS immunoprecipitates prepared from both human tonsil cells and lymphoblastoid B-cell lines but was not observed in control precipitates or in association with immunoglobulin or class I HLA molecules. Preliminary biochemical studies indicate that this Mr 40,000-70,000 molecule is polyanionic, disperse in molecular weight, and sensitive to protease digestion. The sulfate-bearing moiety of this component was resistant to Pronase but sensitive to chondroitinase ABC, indicating that this molecule belongs to the chondroitin sulfate class of proteoglycans.
mesh_terms: D000293:Adolescent; D002460:Cell Line; D002906:Chromosomes, Human, 6-12 and X; D004591:Electrophoresis, Polyacrylamide Gel; D005802:Genes, MHC Class II; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006801:Humans; D007930:Leucine / Q000378:metabolism; D008214:Lymphocytes / Q000276:immunology*; D046911:Macromolecular Substances; D008285:Major Histocompatibility Complex; D008297:Male; D008970:Molecular Weight; D014066:Palatine Tonsil / Q000276:immunology; D013431:Sulfates / Q000378:metabolism; D013462:Sulfur Radioisotopes; D014316:Tritium
chemical_list: D000949:Histocompatibility Antigens Class II; D046911:Macromolecular Substances; D013431:Sulfates; D013462:Sulfur Radioisotopes; D014316:Tritium; D007930:Leucine