[Demonstration of C3-binding circulating immune complexes using Raji, conglutinin and anti-C3 assays--a critical...

There remains no doubt at the present time, that the appearance of circulating immune complexes in illness accompanying vasculitis and for glomerulonephritis correlates with the severity of disease. Moreover, immune complexes are of diagnostic importance where infections with a chronic development or neoplastic diseases are concerned. The choice of IC test system should incorporate their essential biological functions and identify those IC that activate the complement cascade both by the classical and the alternative route. The detection of IC bound C3 cleavage products (C3b, C3bi, C3d) represents the key to identification of a wide range of IC. Of the presently available methods Raji cell test, conglutinin- and anti C3-IC assay, on critical appraisal, the anti C3-IC assay represents the most applicable way of defining complement binding IC. The advantage of this system is that appreciable disturbances and limitations that influence other systems do not affect the antigen-antibody reaction which is the core of the anti C3 assay.