Immunoenzymatic colorimetric method for quantitative determination of Circulating Immune Complex C3d (CIC C3d) concentration in human serum or plasma.
CIC C3d ELISA kit is intended for laboratory use only.
The importance of the immunocomplex (CIC) and their relation with several diseases have been object of investigations for many years. The enstablishment of immunocomplex is a normal protecting process of the immune system. The circulating immunocomplex are removed from the circulation by means of various cellular, biochemical and enzymatic processes. Key of elimination of many CIC is the activation of the classic way of the complement. In some diseases, of difficult understanding, the immunocomplex can begin the damaging of tissue and organs. In this case the activation of the complement can lead to the anafilotoxine production, stimulation of leukocyte and activation of macrophage and other cells. In some cases of glomerulonephritis, in which the immunocomplex fix to the cellular membranes, it has the destruction of the tissue. Circulating immuno-complexes
(CIC) are present in many individuals affections from systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), especially in those affections from vasculitis complications. There are many tests for the determination of CIC, included the test of precipitation with PEG, radial immunodiffusion, and cellular tests like the test of Ray cell.
Does not exist one procedure to determinate all types of immunocomplex; in commerce some tests to determinate fragments of the complex are available (E.g. C1q and C3d), that have an important diagnostic meaning.
C3d-fixing circulating immune complexes (CIC) are first blocked by the anti-C3d immobilized on the microplate. During this phase, the immunocomplex binds to the antibodies anti C3d coated on the microplate. The microplate is washed to remove the unbound serum protein. In the second phase, the anti-human IgG antibodies conjugated with peroxidase are added; they bind to the immunocomplex fixed on the microplate. The washing solution removes the unbound conjugate. In the third phase, the TMB Substrate is added, and reacts with the conjugate fixed on the microplate. The quantity of CIC IgG complex is proportional to the colour intensity read at 450 nm wavelengths. The immunocomplex concentration in the sample is calculated through a calibration curve. “Heat aggregate human gamma globulin per mL” (_gEq/mL) is the unit of measure of the results.