Detection of a cytokeratin determinant common to diverse epithelial cells by a broadly cross-reacting monoclonal antibody.

A monoclonal antibody derived from a mouse immunized with bovine epidermal prekeratin has been characterized by its binding to cytoskeletal polypeptides separated by one- or two-dimensional gel electrophoresis and by immunofluorescence microscopy. This antibody (KG 8.13) binds to a determinant present in a large number of human cytokeratin polypeptides, notably some polypeptides (Nos. 1, 5, 6, 7, and 8) of the 'basic cytokeratin subfamily' defined by peptide mapping, as well as a few acidic cytokeratins such as the epidermis-specific cytokeratins Nos. 10 and 11 and the more widespread cytokeratin No. 18. This antibody reacts specifically with a wide variety of epithelial tissues and cultured epithelial cells, in agreement with previous findings that at least one polypeptide of the basic cytokeratin subfamily is present in all normal and neoplastic epithelial cells so far examined. The antibody also reacts with corresponding cytokeratin polypeptides in a broad range of species including man, cow, chick, and amphibia but shows only limited reactivity with only a few rodent cytokeratins. The value of this broad-range monoclonal antibody, which apparently recognizes a stable cytokeratin determinant ubiquitous in human epithelia, for the immunohistochemical identification of epithelia and carcinomas is discussed.