Production and Characterization of a Monoclonal Antibody to Bovine Estrogen Sulfotransferase

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Abstract
A murine IgGl (.kappa.) monoclonal antibody, termed 33-11, was produced against purified bovine estrogen sulfotransferase. After the enzyme was separated into its four isoenzyme forms by native polyacrylamide gel electrophoresis, a Western blotting analysis indicated that the antibody reacted to the similar extent with each of the isoenzymes. As immunoprecipitation and SDS-poly acrylamide gel electrophoresis analysis was performed with an I-125-labeled enzyme preparation. Antibody 33-11 precipitated protein in the molecular weight range 70,000-74,000, the size of native estrogen sulfotransferase, plus additional bonds with molecular weights of 29,000, 54,000, and 61,000. The lower molecular weight polypeptides may represent fragments, bearing a common epitope, produced by limited endogenous proteolysis of the intact enzyme. Solid-phase radioimmunoassay testing demonstrated strong and specific binding of the antibody to the bovine enzyme. No cross-reactivity was observed with a panel of nine other purified bovine proteins. An immunohistochemical analysis with the antibody was performed on two bovine tissues with high levels of enzyme activity. Placenta showed strong, specific staining of fetal giant cells of chorionic villi, while adrenal had weak but wide-spread staining which tended to be more concentrated in the inner cortex. Monoclonal antibody 33-11 has potential utility in the purification, detection, and quantitation of bovine estrogen sulfotransferase.