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Assay Description:





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CS-846 Aggrecan Cartilage Synthesis Competition Assay
"Aggrecan Chrondroitin Sulfate 846 Epitope" )CPII

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Clinical Applications:

This serum assay monitors changes in the rate of synthesis of cartilage components (aggrecan) indicative of Osteoarthritis (OA) and Rheumatoid Arthritis (RA)..


In arthritic joints the cartilage matrix is disrupted leading to changes in proteoglycan content. The CS-846 assay detects large fetal forms of aggrecan with at least one CS846 epitope, which is thought to be synthesized in adult cartilage in an attempt to repair damage.  Molecules of fetal aggrecan measured in the serum with this assay have been released from cartilage following cleavage by matrix metalloproteinase (MMP) and/or aggrecanase enzymes.

How the Assay Works:

This one-step competitive immunoassay is an antibody capture model in a 96-well format. Unlabelled fetal bovine proteoglycan standards and diluted unknown serum samples (1/5) are added onto the ELISA plate. Biotin-labelled fetal bovine proteoglycan is added in all wells followed by monoclonal mouse CS846 antibody (IgM) to start the competition. This mixture is incubated for 2 hours on a plate shaker to facilitate binding of unlabeled aggrecan (standard and samples) and of biotin-labeled aggrecan to the CS846 antibody, to the goat anti-mouse IgM coated on the plate. Streptavidin conjugated to horseradish peroxidase (HRP) is added to bind to any bound biotinylated aggrecan. Tetra-methylbenzidine (TMB) substrate is added then HRP degrades H202 and oxidizes TMB to form a blue product. The reaction is stopped and signal amplified with an acid, which converts the product from a blue to a yellow colour that can be quantified at 450 nm. The optical density (OD) at 450 nm is inversely proportional to the amount of CS846 epitopes.