Enzyme immunoassay of C1q and its application to the detection of C1q antigens in urine.
A highly sensitive enzyme immunoassay for the determination of C1q, a subcomponent of the first component of complement, C1, was developed to determine C1q in body fluid. Anti-C1q F(ab')2 fragments were immobilized on silicone rubber and after the interaction of anti-C1q with C1q, Fab' fragments of anti-C1q coupled with beta-D-galactosidase were added. The amounts of C1q were measured by enzymatic activity of beta-D-galactosidase to cleave 4-methylumbelliferyl-D-galactoside. A calibration curve of C1q indicates that C1q could be determined in the range of 0.3 ng/ml-1 mg/ml, the optimal range being 1-100 ng/ml. While C1q was not detectable in the urine of healthy volunteers, C1q could be determined in the urine of patients with renal diseases. The highest level of C1q detected was 31.8 ng/ml in urine of chronic nephritis.
D003166:Complement Activating Enzymes / Q000032:analysis* / Q000276:immunology; D015922:Complement C1q; D005921:Glomerulonephritis / Q000652:urine; D006801:Humans; D007124:Immunoenzyme Techniques; D007140:Immunoglobulin Fab Fragments; D007202:Indicators and Reagents; D009393:Nephritis / Q000652:urine; D012016:Reference Values
D007140:Immunoglobulin Fab Fragments; D007202:Indicators and Reagents; D015922:Complement C1q; D003166:Complement Activating Enzymes