Monoclonal antibody HISL-19 as an immunocytochemical probe for neuroendocrine differentiation. Its application in...

The monoclonal islet cell antibody HISL-19 was generated after immunization of BALB/c mice with human islet cell preparations. Besides reactivity with all cells of the human pancreatic islet, MAb HISL-19 also reacted with other cells of the diffuse neuroendocrine system, including anterior pituitary cells, C cells of the thyroid, endocrine cells of the gut and bronchus, the adrenal medulla, and central and peripheral neurons. In this study the authors screened a series of 53 neuroendocrine and 71 nonneuroendocrine tumors for their reactivity with MAb HISL-19 using an indirect immunoperoxidase technique on formalin-fixed and Paraplast-embedded sections. MAb HISL-19 reacted strongly with all insulomas (10), carcinoids (8), C-cell carcinomas of the thyroid (8), pituitary adenomas (6), neuroendocrine carcinomas of the skin (4), paragangliomas of the carotid body (3), and pheochromocytomas (2) tested. Neuroblastomas (3), oat-cell carcinomas of the lung (2), and melanomas (4) exhibited only very few immunoreactive cells scattered throughout the tumor or remained unstained with MAb HISL-19. With the exception of one lobular carcinoma of the breast (1/3), one adenocarcinoma of the endometrium (1/4), and one adenocarcinoma of the stomach (1/6), nonneuroendocrine tumors were negative with MAb HISL-19. Biochemical findings obtained by SDS-PAGE, "Western" immunoblotting, immunoaffinity chromatography, and absorption experiments indicate that the MAb HISL-19-defined antigen is not related to neuron specific enolase. Because the epitope recognized by MAb HISL-19 is well preserved in formalin-fixed and routinely processed tissues, this monoclonal antibody finds potential applications in diagnostic pathology as an indicator for neuroendocrine cells and their neoplasms.