A new immunoassay was developed to detect denaturation of type II collagen in osteoarthritis (OA). A peptide, al(II)-CBllB, located in the CB11 peptide of type II collagen, was synthesized and used to produce a monoclonal antibody (COL2-3/4m) of the IgG,(K) isotype. This reacts with a defined epitope in denatured but not native type II collagen and the a3 chain of type XI collagen. The latter is present in very small amounts (about 1% wt/wt) in cartilage relative to the al (II) chain. By using an enzyme-linked immunosorbent assay, type II collagen denaturation and total type II collagen content were determined. The epitope recognized by the antibody was resistant to cleavage by a-chymotrypsin and proteinase K which were used to extract al (II)-CB11B from the denatured (a-chymotrypsin soluble) and residual native (proteinase K soluble) collagen a-chains, respectively, present in human femoral articular cartilage. Type II collagen content was significantly reduced from a mean (range) of 14% (9.2-20.8%) of wet weight in 8 normal cartilages to 10.3% (7.4-15.0%) in 16 OA cartilages. This decrease, which may result in part from an increased hydration, was accompanied by an increase in the percent denaturation of type II collagen in OA to 6.0% of total type II collagen compared with 1.1% in normal tissue. The percent denaturation was ordinarily greater in the more superficial zone than in the deep zone of OA cartilage. (J. Clin. Invest.
Antibodies were used in radioimmunoassays with gel chromatography to detect the hyaluronic acidbinding region, core protein, and keratan sulfate of human cartilage protoeglycan in the synovial fluids of patients with rheumatoid arthritis, juvenile rheumatoid arthritis, and osteoarthritis. All fluids contained proteoglycan that was mainly included on Sepharose CL4B; this result indicates cleavage of proteoglycan (which is normally excluded). The hyaluronic acidbinding region was the smallest and most commonly detected fragment. It was relatively free of keratan sulfate and core protein, and it could sometimes bind to hyaluronic acid. Other larger fragments containing core protein and/or keratan sulfate were detected in every fluid.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.