A monoclonal antibody against human colon cancers

A monoclonal antibody was prepared by hybridizing mouse myeloma cells with spleen cells from the mouse which was immunized with human colon cancer transplanted in nude mice. The reactivity of the monoclonal antibody, named A7, was tested by immunoperoxidase method. A7 reacted strongly with human adenocarcinoma cell lines and carcinoembryonic antigen (CEA). In surgical specimens, A7 reacted with 10 cancer tissues and 2 normal colon mucosa from 19 colorectal cancer patients. A7 did not react with other cancers. It was thought that A7 reacted with colon- or colon cancer-specific CEA. The reactivity of A7 with colorectal cancers was markedly reduced by preoperative irradiation.