title: C1 activation and dissociation in disease.
abstract: The composition of complexes containing C1 inactivator (C1 IA), C1r and C1s was investigated in normal serum after activation of C1 under various conditions. Analyses were performed with PAGE of eluates from Sepharose beads coated with F(ab')2 fragments of anti C1s followed by immunoblotting with anti C1 IA, anti C1s or anti C1r. Eluates obtained from serum treated with aggregated IgG (AGG) contained C1 IA in complex with C1r and C1s with both subcomponents in activated form. Eluates from serum incubated at 37 degrees C for 1, 2 or 3 days without activators showed C1 IA complexed with activated C1r and with C1s in proenzyme state associated to the complex. On analysis of serum, treated as mentioned above, by a variant of the electroimmunoassay using an intermediate gel containing anti-C1 IA and with anti-C1s in the anodal gel the two types of C1r--C1s--C1 IA complexes could be distinguished. Investigation of fresh sera and synovial fluids from patients with rheumatoid arthritis in this assay showed complexes containing C1 IA and C1r-C1s in activated form in the synovial fluids, while C1 IA-activated C1r-proenzyme C1s complexes were found in the corresponding sera.
mesh_terms: D001172:Arthritis, Rheumatoid / Q000276:immunology*; D003166:Complement Activating Enzymes / Q000032:analysis; D003167:Complement Activation; D003172:Complement C1 / Q000032:analysis / Q000276:immunology*; D003174:Complement C1 Inactivator Proteins / Q000032:analysis; D015923:Complement C1r; D003173:Complement C1s; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007118:Immunoassay; D007163:Immunosorbent Techniques; D013582:Synovial Fluid / Q000276:immunology
chemical_list: D003172:Complement C1; D003174:Complement C1 Inactivator Proteins; D003166:Complement Activating Enzymes; D015923:Complement C1r; D003173:Complement C1s