CHARACTERIZATION OF MONOCLONAL-ANTIBODIES GENERATED AGAINST BOVINE AND PORCINE PROSTACYCLIN SYNTHASE AND QUANTITATION OF BOVINE PROSTACYCLIN SYNTHASE

Monoclonal antibodies were raised against prostacyclin synthases purif ied from bovine and porcine aortae, respectively. Two monoclonal antib odies, RSI and RS2, were purified and characterized. As shown by enzym e activity precipitation and Western blot analysis, in solubilized bov ine and porcine aortae microsomes the monoclonal antibodies reacted on ly with prostacyclin synthase. The monoclonal antibody RS1 cross-react s with partially purified prostacyclin synthase from human umbilical v eins in an ELISA-based assay. None of the antibodies inhibited the enz yme activity. By combination of the monoclonal antibody RS2 with a pol yclonal antibody we established an enzyme-linked immunosorbent assay ( ELISA) for quantitation of bovine prostacyclin synthase. ELISA data we re confirmed by Western blot analysis. Among different bovine tissues, aortae with 1665 +/- 200 ng/mg microsomal protein showed the highest content of PGIS. Significant lower concentrations were observed in ton gue, lung, kidney and thymus ranging from 49 +/- 13.4 to 2.7 +/- 0.9 n g/mg protein. The monoclonal antibody RS1 binds to endothelial cells a nd vascular smooth muscle cells in human liver tissue.