Enzyme-linked immunosorbent assay for hyaluronate using cartilage proteoglycan and an antibody to keratan sulfate

An enzyme-linked immunosorbent assay has been developed to measure hyaluronate concentrations in biological samples. The assay is based on the aggregation of hyaluronate with cartilage proteoglycan monomer, followed by binding of a monoclonal antibody to the keratan sulfate on the proteoglycan. The sensitivity of the assay is 10 ng hyaluronate/ml of either serum or conditioned cell culture medium. The coefficient of variability was between 10 and 20%. Hyaluronate added to samples was recovered quantitatively and digestion of cell culture medium with protease did not affect the concentration of hyaluronate. Hyaluronate polysaccharides as small as a decasaccharide can be measured. This sensitive and convenient assay can be used for measuring large numbers of biological samples from a variety of animal and tissue sources.