title: A solid-phase anti-C3 assay for detection of immune complexes in six distinguished forms.
abstract: A solid-phase anti-C3 assay detecting immune complexes associated with C3 fragments is described. Two monoclonal antibodies against C3 fragments are used; one recognizes an epitope expressed on C3b, C3c and C3i, the other recognizes an epitope expressed on C3dg and iC3b. Combining these monoclonal anti-C3s with antibodies against class-specific immunoglobulins in enzyme-linked immunosorbent assay (ELISA), immune complexes (ICs) are detected in six distinguished forms; C3b-IgG-IC, iC3b/C3dg-IgG-IC, C3b-IgA-IC, iC3b/C3dg-IgA-IC, C3b-IgM-IC and iC3b/C3dg-IgM-IC. About three-fourths of the plasma samples from patients with active SLE or IgA-nephritis were found positive in one or more types of ICs. IgA-type ICs were found very frequently in patients with autoimmune or renal diseases.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D000936:Antigen-Antibody Complex / Q000032:analysis*; D003176:Complement C3 / Q000276:immunology*; D003179:Complement C3b / Q000276:immunology; D015932:Complement C3c; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D000939:Epitopes / Q000276:immunology; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis / Q000276:immunology; D007074:Immunoglobulin G / Q000032:analysis / Q000276:immunology; D007075:Immunoglobulin M / Q000032:analysis / Q000276:immunology; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D009393:Nephritis / Q000276:immunology; D010446:Peptide Fragments / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D003176:Complement C3; D000939:Epitopes; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D010446:Peptide Fragments; C045477:complement C3d,g; D003179:Complement C3b; D015932:Complement C3c