[Production of monoclonal antibody against a newly established human endometrial cancer cell line SNG-II].

A cell line designated SNG-II was established from the operation specimen of human endometrial adenocarcinoma, and by means of an immunization procedure using intact SNG-II cells, a monoclonal antibody (Mab) named MSN-1 which reacts immunohistochemically with endometrial cancers was obtained. The cell line grew well without interruption for over 5 years, and, SNG-II cells produced tumors of cell differentiated adenocarcinoma in nude mice. The modal chromosomal number was diploid without a marker chromosome. The production of human chorionic gonadotropin and its beta-subunit, CA-125, tissue polypeptide antigen, and placental proteins such as PP6 and PP7 in SNG-II was confirmed. MSN-1 was of IgM subclass. As the antigenic reactivity was unchanged by trypsin treatment, but lost by periodic treatment, it was suggested that the antigen corresponding to MSN-1 was a carbohydrate sequence. Immunohistochemically MSN-1 reacted with about 70% cases of endometrial adenocarcinoma, but seldom with normal endometrium. Furthermore, the staining pattern of MSN-1 was different in benign cells from that in malignant cells: only the luminal surface of the normal endometrium was positive, whereas the cytoplasma was also stained in many of adenocarcinoma cells.