Complement C4D ELISA Kit [Human] (CAT#: CB-P057-K) Datasheet

Kit

The complement system plays an essential role in autoimmune and infectious diseases. There are three pathways of complement activation; the classical, the alternative and the lectin pathway. The C4d protein is a product of the classical and the lectin pathways. C4d, a degradation end product produced during complement C4 activation, had been recognized as a biomarker for its stability and strong association with antibody-mediated rejection in the 1990s and in the last twenty years, the potential importance of C4d in SLE as a tool for diagnosing and monitoring SLE was highlighted. Particularly, C4d associates with SLE nephritis. In primary Sjogren's syndrome (pSS) the level of C4d correlates with anti-SSB and κ/λ ratio and is suggested to be an appropriate marker of antibody response and complement activation in pSS patients with auto-antibodies. Plasma level of C4d has been shown to be significantly higher in patients with antibody-associated vasculitis with active disease compared with patients with lupus nephritis and normal controls. C4d has the potential to detect patients at risk for the consequences of antibody-mediated disease. Furthermore, the development of new therapeutics that block complement activation makes C4d a marker with potential to identify and monitor patients who may possibly benefit from these drugs. Complement assays based on detection of linear neoepitopes has been reported to have an advantage compared to conformational epitopes, as it reduces the risk of false positives and increases specificity. This complement assay is based on the detection of the short linear C4d neoepitope exposed at the cleavage site of C4 after activation. The Complement C4d assay is an enzyme-linked immunosorbent assay (ELISA) for the semiquantitative determination of C4d in human plasma.

This kit is for research use only and cannot be used for diagnosis.
This kit has been used to test EDTA plasma. Other matrices have not been tested.

The device is a colorimetric sandwich ELISA kit. Samples are diluted in assay diluent and 100µL
diluted sample is transferred to the microtiter wells and incubated at room temperature for 60
minutes. During this first incubation C4d in the sample is captured by the anti-C4d-Neo monoclonal
antibody, pre-coated on the surface of the microtiter wells. After washing to remove unbound
material, a second horseradish peroxidase (HRP) labelled monoclonal antibody, that binds to both
allelic variants of C4d (A and B), is added the to the well. After incubation for 30 minutes the wells
are washed again, and a substrate is added and incubated. The color development is stopped after
30 minutes, and the color is measured in a spectrophotometer. The color is directly proportional to
the amount of C4d bound to the well. The amount of C4d is determined by comparison to the color
development of the calibrator samples.