An antigen specific to hyperplastic liver nodules defined with monoclonal antibody: a new marker for preneoplastic cells in rat chemical hepatocarcinogenesis.

Two monoclonal antibodies (MoAbs) were prepared against the hepatocytes of hyperplastic liver nodules from rats killed in the 13th week during hepatocarcinogenesis with 2-acetylaminofluorene. The specificity of these MoAbs was confirmed by cellular radioimmunoassay. By means of immunoperoxidase staining with 2 MoAbs (HAM 6 and HAM 7), HAM 6-defined antigen was detected on the plasma membrane and/or cytoplasm of the hepatocytes in hyperplastic nodules, while HAM 7 reacted to the hepatocytes surrounding hyperplastic nodules. Therefore, HAM 6 seemed to be specific to hyperplastic nodules, but HAM 7 to be a MoAb developed accidentally to the surrounding hepatocytes by contamination of the cell suspension of hyperplastic nodules.