Human pancreatic cell surface antigens with homologous expression in liver, sweat glands, and other exocrine tissues.

We have generated two panels of monoclonal antibodies (MoAbs) that represent a unique array of immunolabeling reagents specific for diverse cell surface and intracellular antigens of ductal epithelial cells (DEC) and of acinar cells (AC) within the human pancreas. Eight of the MoAbs are specific within the pancreas for the DEC plasma membrane (PM), three for DEC intracellular antigens, seven for AC-PM, and one for AC secretory granules. The MoAbs with PM reactivities have permitted us to substantially enhance our assessment of exocrine contamination in our human islet preparations. However, we have been unable to demonstrate consistently the effectiveness of these MoAbs in complement-mediated cytotoxicity protocols designed to improve the purity of our islet preparations by exocrine cytolysis. It is possible that primary cell isolates of pancreas or epithelial organs in general may lack inherent susceptibility to complement-mediated cytolysis or, instead, that this particular panel of MoAbs lacks the appropriate characteristics needed to achieve consistent complement-mediated cytolysis. We have also begun to explore the potentially broader applicability of the anti-DEC MoAbs as immunocytochemical tools and have observed intriguing patterns of cross-reactivities in other exocrine tissues, particularly bile duct epithelial cells in the liver and functionally discrete subsets of DEC in the eccrine sweat gland and the parotid gland. These homologous antigenic patterns, by virtue of their specificities for ductal tissue, most likely reflect the molecular bases for functions common to these tissues, e.g., active ion transport and mucin secretion. In addition, the anti-DEC and the anti-AC MoAbs exhibit patterns of binding specificity for human cell lines derived from pancreatic adenocarcinoma that suggest the potential value of these MoAbs in tumor diagnosis and therapy. We believe that these panels of MoAbs will find broad utility in immunopathology and in experimental approaches to questions regarding the development, normal function, and pathogenetic mechanisms in the human pancreas and other related organs as well.