A monoclonal antibody, SKH1, reacts with 40 Kd sweat gland-associated antigen

Several monoclonal antibodies (MAB) have been produced using an eccrine carcinoma cell line as an immunogen. One such MAB, SKH1, reacted with both the secretory portion and coiled duct of the eccrine and with the secretory portion of apocrine gland. SKH1, however, did not react with myoepithelial cells, intradermal ducts of both types of sweat gland, or with other components of normal axillary skin including the epidermis and follicular apparatus. The reaction was strongest if the specimen was fixed with 80% methanol, and moderate on non-fixed or acid-alcohol-fixed specimens. Only weak reaction was obtained on cold acetone-fixed specimens, and reaction was negative with formalin-fixed, paraffin-embedded tissues. SKH1 reacted positively with the cytoskeleton of the eccrine carcinoma cell line, Colo-16 and MCF-7. Applied to pathological skin specimens, SKH1 reacted with the tumor cells of clear cell hidradenoma, syringocystadenoma papilliferum, and extramammary Paget's disease. SKH1 also reacted with the tumor cells of metastatic adenocarcinomas arising from lung, breast and ovary. SKH1 did not react with the majority of tumor cells of eccrine poroma, but reacted with single-layered cells lining narrow ductal lumina. SKH1 did not react with epithelial cells lining cystic or ductal lumina of syringoma, but reacted moderately with the amorphous keratin-like substance filling the lumina. Immunoblot analysis revealed that SKH1 recognizes a 40 Kd sweat gland-associated antigen, and can be an aid to identifying tumors arising from sweat gland structures.