Production of monoclonal antibody against the C1 component of rat estramustine-binding protein: immunohistochemical study of rat prostate.

The monoclonal antibody against estramustine-binding protein (EMBP) was produced by immunizing a mouse with EMBP antigen purified from rat ventral prostate. On western blotting analysis this antibody recognized the EMBP C1 component, and in an absorption test it recognized the EMBP antigen. Immunohistochemically, this antibody revealed positive staining for the ventral and dorsolateral prostate. In the epithelium of the ventral prostate, intense immunostaining was observed in the intraluminal secretory product; however, in the epithelium of the dorsolateral prostate, the staining was intense in the cytoplasm of the epithelial cells. These findings suggested differences of EMBP localization in the ventral and the dorsolateral prostate. Since the intensity of immunostaining for EMBP was decreased in the prostate of castrated rats, we considered that this antibody reflected the androgen dependency of EMBP.