Expression of a monoclonal antibody‐defined liver‐associated antigen in normal rat hepatocytes and hepatocellular carcinoma cells

In order to examine changes in the expression of normal cellular antigens during hepatocarcinogenesis, we have developed and characterized a monoclonal antibody detecting an antigen which is particularly associated with adult rat hepatocytes. The antibody showed no reactivity with a range of freshly-prepared normal syngeneic adult rat cell types, but showed strong reactivity with hepatocytes derived from several rat strains in antibody binding tests. Immunoperoxidase staining of sections of normal rat liver showed that the antigen was distributed throughout hepatocytes within the liver, but did not stain cells other than hepatocytes. The antigen detected by this monoclonal antibody was not detectable on a number of transplanted and primary dimethylaminoazobenzene-induced hepatomas. Preliminary data indicated that this monoclonal antibody may be suitable for use in flow cytofluorimetric sorting of mixed populations of normal and tumour cells, allowing the investigation of cell phenotypes during hepatocarcinogenesis.