Binding of complement components C1q, C3, C4 and C5 to a model immune complex in ELISA.
When normal human serum is added to microELISA plates coated with monomeric or aggregated IgG various complement components become bound and can be detected with specific chicken anti-C1q, anti-C3, anti-C4 and anti-C5 antibodies. Using such assays we found increased C1q- and decreased C3- and C4-binding in sera from patients with SLE. In contrast, sera from patients with rheumatoid arthritis showed decreased C3 binding but normal C1q binding. The decreases in C3 and C4 binding observed in the sera from patients with SLE were larger than the corresponding decreases determined by radial immunodiffusion. Comparing these results with those of the CH50 assay, the correlation coefficient between CH50 and the C3-binding assay was 0.48. There was no correlation between the results of the CH50 and those of the C1q-, C4- or C5-binding assays.
Larsson
A
A
Department of Medical and Physiological Chemistry, Biomedical Centre, Uppsala, Sweden.
Sjöquist
J
J
D000936:Antigen-Antibody Complex / Q000378:metabolism*; D001172:Arthritis, Rheumatoid / Q000097:blood; D003166:Complement Activating Enzymes / Q000097:blood; D003172:Complement C1 / Q000097:blood; D015922:Complement C1q; D003176:Complement C3 / Q000097:blood; D003181:Complement C4 / Q000097:blood; D003182:Complement C5 / Q000097:blood; D003165:Complement System Proteins / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D006461:Hemolysis; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D008180:Lupus Erythematosus, Systemic / Q000097:blood; D011951:Receptors, Complement / Q000032:analysis*
D000936:Antigen-Antibody Complex; D003172:Complement C1; D003176:Complement C3; D003181:Complement C4; D003182:Complement C5; D007074:Immunoglobulin G; D011951:Receptors, Complement; D015922:Complement C1q; D003165:Complement System Proteins; D003166:Complement Activating Enzymes