Sandwich radioimmunoassay using single monoclonal antibody that detects minute amounts of melanoma antigens from various mammalian species.

A sensitive sandwich radioimmunoassay for the detection of minute amounts of melanoma antigens from various mammalian melanomas was established by using a syngeneic mouse monoclonal anti-melanoma antibody (M2590). The assay system detected the soluble mouse and human melanoma antigens equally at a concentration of 10(3)-10(4) cells/ml because the M2590 antibody was found to react specifically with cross-species melanoma antigenic determinants composed of the carbohydrate side chains of the 31,000-dalton glycoprotein uniquely expressed on various mammalian melanoma cells. Furthermore, human melanomas of various types, such as melanotic, amelanotic, primary, metastatic etc., were successfully detected in an antigen-specific manner. Therefore, the present sandwich assay system using a single monoclonal antibody should be quite useful in clinical applications, especially in the diagnosis of human melanomas.