[Radioimmunoassay for type II amino-terminal procollagen peptide. Technical note].

We have studied the immunoreactivity of human sera and synovial fluids in a radioimmunoassay which utilizes an anti-bovine procollagen type III antiserum and the bovine type III procollagen peptide as standard and tracer. We have noticed a complete cross reaction between bovine col 1-3 and human synovial fluid, which thus contains substance (s) having the same antigenic determinant (s) as col 1-3. On the contrary, we have demonstrated non parallelism between col 1-3 and human serum, whether the serum was obtained from normal subjects or patients suffering from various diseases. These results suggest that immunoreactive substances related to col 1-3 and detected in sera are at least partially different from those detected in synovial fluids.