A monoclonal antibody reacting with various human carcinomas and fetal colon and esophagus.

A monoclonal antibody 9A3 was raised to human gastric carcinoma cell line TMK-1, a poorly differentiated adenocarcinoma of the stomach. 9A3 antibody (IgG1, kappa) strongly reacted with various carcinomas immunohistochemically, but did not react with any normal tissues of the whole body tested except for neutrophiles and macrophages. 9A3 antibody also reacted with the luminal surface of the fetal colon and esophagus at six months of gestation. The antigen recognized by 9A3 antibody might be an oncodevelopmental antigen.