A monoclonal antibody, CSTO-1, against a stomach adenocarcinoma-associated antigen.

A monoclonal antibody, CSTO-1, has been produced against a stomach adenocarcinoma-associated antigen. The antibody is cytotoxic to stomach, colon, and lung adenocarcinoma lines but is completely noncytotoxic to normal blood elements and leukemic cell lines. The monoclonal antibody reacts with tumor cell membranes in enzyme-linked immunosorbent assay and is negative to cell membranes from various normal tissues. By immunoperoxidase testing, the antibody reacts with 18 of 22 stomach adenocarcinomas, 11 of 16 colon adenocarcinomas, 3 of 4 squamous cell carcinomas of the lung, and 1 of 4 lung adenocarcinomas. In addition, the antibody reacts with the superficial epithelium of normal tissues such as colon, stomach, esophagus, acinar cells and duct epithelium of the pancreas, bronchial epithelium of the lung, and sweat duct epithelium of the skin. Thus, the CSTO-1 antibody reacts to an antigen present in normal superficial epithelia, as well as on various tumors. It is of potential use in detecting these antigens on tumor sections and eventually may be used in immunotherapy.