IMMUNOASSAY FOR INTACT AMINO-TERMINAL PROPEPTIDE OF HUMAN TYPE-I PROCOLLAGEN

We have developed quantitative immunoassays for the intact, trimeric a mino-terminal propeptide of human type I procollagen (PINP) and its Ce ll domain. Intact PINP was isolated from the pleural fluids of cancer patients by a combination of ion-exchange, gel-filtration, and reverse d-phase chromatographies, The amino-terminal Cell domain of PINP was i solated after bacterial collagenase treatment of the heat-denatured tr imeric propeptide. For the intact PINP assay we used a polyclonal anti body with only 1.2% cross-reaction with the monomeric Coil domain, In human serum, this assay detects only one peak of PINP antigenicity tha t has the size of known intact PINP. Under similar conditions, an assa y for the Coil domain of PINP recognized two circulating antigens. The biological relevance was further verified in wound fluid, Interassay and intraassay CVs were 3.1-9.3% for values within the reference inter vals (mean +/- 2SD) for intact PINP in serum, which were 19-84 mu g/L for women and 20-76 mu g/L for men.