title: Epitopes of proteoglycans eliciting an anti-proteoglycan response in chronic immune synovitis.
abstract: This study details the immune response to cartilage proteoglycan in experimental chronic IgG-induced immune synovitis. Antibodies reactive with purified rabbit proteoglycan monomer were observed in nine of nine rabbits with immune synovitis. IgG-immunized but nonsynovitic control animals with no pathology showed no antibody response. A panel of murine monoclonal antibodies with defined specificity towards rabbit proteoglycan were utilized to characterize the epitope specificity of the immune synovitis polyclonal anti-proteoglycan response. One murine monoclonal antibody, 6C11, inhibited the binding of the polyclonal antisera to proteoglycan in all nine animals with significant (greater than 40%) inhibition in six of nine rabbits. Further inhibition studies utilizing DEAE-cellulose-resolved proteoglycan tryptic peptides revealed that peptides poor in chondroitin sulfate were strong inhibitors of binding of the polyclonal antibodies to the proteoglycan substrate. In particular, keratan sulfate-containing tryptic peptides were most inhibitory on a per weight basis. These results indicate that, in chronic IgG-induced immune synovitis, anti-proteoglycan antibodies elicited are heterogeneous with regard to specificity, but a relatively large proportion predominantly recognized a portion of the proteoglycan molecule containing core protein and associated keratan sulfate.
mesh_terms: D000818:Animals; D001323:Autoantibodies / Q000032:analysis*; D001327:Autoimmune Diseases / Q000276:immunology* / Q000473:pathology; D002908:Chronic Disease; D004195:Disease Models, Animal; D000939:Epitopes / Q000032:analysis*; D007074:Immunoglobulin G; D010446:Peptide Fragments / Q000276:immunology; D011509:Proteoglycans / Q000276:immunology*; D011817:Rabbits; D011863:Radioimmunoassay; D013585:Synovitis / Q000276:immunology* / Q000473:pathology
chemical_list: D001323:Autoantibodies; D000939:Epitopes; D007074:Immunoglobulin G; D010446:Peptide Fragments; D011509:Proteoglycans