Detection of immune complexes by a new assay, the polyethylene glycol precipitation-complement consumption test (PEG-CC).
A new assay for the detection of circulating immune complexes, the polyethylene glycol precipitation-complement consumption assay (PEG-CC), is described. The test is both simple and sensitive, and exhibits a high degree of specificity. Immune complexes are first isolated from serum by precipitation in 2.5% polyethylene glycol (PEG) and concentrated. They are then assayed functionally by measuring their ability to fix complement using a sensitive kinetic assay for total haemolytic complement. The test can detect aggregated IgG in serum at concentrations around 6.0 micrograms/ml (about 2.0 micrograms absolute. Using DNA-anti-DNA and ovalbumin-anti-ovalbumin immune complexes prepared in vitro, antigen concentrations less than 0.5 micrograms/ml can be detected. Interference by endogenous complement, polyanions and other factors in test sera has been virtually eliminted by the design of the assay. The increased specificity of the PEG-CC test for immune complexes, should prove useful in the diagnosis and monitoring of immune complex-mediated diseases.
D000818:Animals; D000936:Antigen-Antibody Complex; D011232:Chemical Precipitation; D003165:Complement System Proteins; D004247:DNA / Q000276:immunology; D004492:Edetic Acid; D005260:Female; D005615:Freezing; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007074:Immunoglobulin G / Q000032:analysis; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D046911:Macromolecular Substances; D008297:Male; D010047:Ovalbumin / Q000276:immunology; D011092:Polyethylene Glycols; D011817:Rabbits; D013696:Temperature
D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G; D046911:Macromolecular Substances; D011092:Polyethylene Glycols; D010047:Ovalbumin; D003165:Complement System Proteins; D004247:DNA; D004492:Edetic Acid