title: Influence of serum complement and rheumatoid factor on detection of immune complexes by the C1q and monoclonal rheumatoid factor solid-phase assay.
abstract: Soluble purified monoclonal and polyclonal rheumatoid factor, total serum complement, and soluble C1q all inhibit the detection of model tetanus toxoid/anti-toxoid immune complexes in the solid-phase C1q assay. The binding of these immune complexes to solid-phase monoclonal rheumatoid factor is less inhibited by soluble C1q and by total serum complement, but clearly decreased by soluble monoclonal or polyclonal rheumatoid factor. Serum complement does not reduce the size of these model complexes. We recommend the use of low ionic strength EDTA (10 mM) to partly neutralize the complement-mediated inhibition. This procedure is shown to be superior to currently used higher EDTA concentrations and to the use of IgG-Sepharose.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D000936:Antigen-Antibody Complex / Q000032:analysis*; D003166:Complement Activating Enzymes / Q000276:immunology; D003167:Complement Activation; D015922:Complement C1q; D003165:Complement System Proteins / Q000276:immunology; D004492:Edetic Acid / Q000494:pharmacology; D007163:Immunosorbent Techniques; D008970:Molecular Weight; D009994:Osmolar Concentration; D012217:Rheumatoid Factor / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D015922:Complement C1q; D003165:Complement System Proteins; D012217:Rheumatoid Factor; D004492:Edetic Acid; D003166:Complement Activating Enzymes