Abstract: Monoclonal antibodies that bind specifically to prostate carcinoma and do not bind substantially to normal prostate or benign prostatic hyperplasia, as well as hybridoma cell lines producing the monoclonal antibodies are disclosed. In one embodiment, a monoclonal antibody designated MAb PD41 is disclosed. A new antigen designated prostate mucin antigen is disclosed in isolated, substantially pure form. In addition, methods for using the hybridoma cell lines, the monoclonal antibody and/or the antigen for diagnosis, prophylaxis and/or treatment of prostate carcinoma are disclosed.

Abstract: An isolated TGF-.beta. supergene family (TSF) receptor polypeptide is provided. This polypeptide preferably is an inhibin/activin receptor polypeptide and has at least 75% sequence identity with the mature human inhibin/activin receptor sequence. Also provided is a method for purifying TGF-.beta. supergene family members such as inhibin or activin using the polypeptide, and a method for screening for compounds with TGF-.beta. supergene family member activity by contacting the compound with the polypeptide and detecting if binding has occurred and the compound is active.