Enzyme linked immunoassay (elisa) for connective tissue proteins: Type 1 collagen

The classical approaches for the quantitation of collagen take advantage of unique features of collagen such as the presence of hydroxyproline 1 or the sensitivity of the protein to bacterial collagenase. 2 However, since these features are common to the different molecular species of collagen, 3 other methods are needed to selectively measure each collagen type. One approach to this problem is to capitalize on the fact that the different collagen types are immunologically distinct and antibodies with high binding affinity specific for each collagen type can be produced.4 Such antibodies can be utilized to quantify human type I collagen in an enzyme-linked immunoassay (ELISA)5 .6 which is sensitive, specific and easily performed. This assay offers several practical advantages over the more familiar radioimmunoassays.7.8 There are two basic types of ELISA tests, direct and inhibition. Both utilize the sensitivity of an enzyme reaction to measure the antigen antibody interaction. Since very sensitive enzyme-substrate-product combinations are available, the test is very powerful.