title: Interaction between fibronectin and C1q in rheumatoid synovial fluid and normal plasma.
abstract: The interaction between fibronectin and C1q was studied in the presence of normal human plasma and rheumatoid synovial fluid by solid phase binding assay. Fibronectin-C1q binding occurred in the presence of rheumatoid synovial fluid but not in the presence of normal plasma. Binding was strongest at 4 degrees C and in the presence of EDTA. Fibronectin-C1q binding could be induced in the presence of normal plasma by hypotonicity, augmentation of the concentration of solution-phase fibronectin or by the addition of heat-aggregated IgG. The C1q present in rheumatoid synovial fluid bound to both aminoterminal collagen-binding and carboxyterminal noncollagen binding fibronectin fragments although binding to the aminoterminal fragment was stronger. The interaction between fibronectin and C1q in rheumatoid synovial fluid may modulate immune-complex deposition and complement activation in the inflamed joint.
mesh_terms: D001172:Arthritis, Rheumatoid / Q000276:immunology*; D002918:Chymotrypsin / Q000494:pharmacology; D003166:Complement Activating Enzymes / Q000378:metabolism*; D003172:Complement C1 / Q000378:metabolism*; D015922:Complement C1q; D004492:Edetic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D005353:Fibronectins / Q000378:metabolism*; D006801:Humans; D010949:Plasma / Q000276:immunology*; D013582:Synovial Fluid / Q000276:immunology*; D013696:Temperature
chemical_list: D003172:Complement C1; D005353:Fibronectins; D015922:Complement C1q; D004492:Edetic Acid; D003166:Complement Activating Enzymes; D002918:Chymotrypsin