A monoclonal antibody recognizing desmosomes: use in human pathology.

A mouse monoclonal IgG1 antibody that recognizes desmosomes in human tissues has been isolated and characterized. DP1 recognizes desmoplakin I (250 kD) in immunoblots of partially purified desmosome preparations. In immunofluorescence microscopy DP1 reacts with desmosomes in epithelial cells from a variety of human tissues including skin, esophagus, uterus, intestine, and in liver hepatocytes. In axilla skin, the epithelial cells in epidermis, sweat glands, and in the outer hair follicles are strongly stained whereas relatively little staining is seen in the epithelial cells of the apocrine glands. Nonepithelial cells are not stained, although decoration of myocardial desmosomes is seen. In cells in culture DP1 is also specific for desmosomes in epithelial cells. Thus the mouse epidermal line HEL, bovine MBCK cells, as well as the human lines A431, HT29, and HeLa are positively stained by DP1. Desmosomes are retained in tumors of epithelial origin such as adenocarcinoma and squamous cell carcinoma. Thus DP1 should be a useful diagnostic marker in human pathology.