Mouse monoclonal antibody (WI-MN-1) against malignant melanoma.

A mouse monoclonal antibody, WI-MN-1, was raised against G-361 melanoma cell line. Reactivity of this antibody was characterized by indirect immunofluorescence against 22 cell lines and normal and neoplastic human tissues. Positive reactions were seen against three melanoma cell lines (G-361, HT-144, and MeWo). It also reacted against an epidermoid carcinoma cell line (Hep-2) and amnion cells (WISH). The antibody failed to react against cell lines derived from granulocytic leukemias, lymphocytic leukemias, Burkitt's lymphoma, carcinoma of the lung, carcinoma of the cervix, carcinoma of the colon, carcinoma of the breast, astrocytoma, and a human monocytoid cell line. Mouse melanoma and mouse fibroblast cell lines were also nonreactive. Similarly, there was no reaction against human peripheral blood, bone marrow, spleen, lymph node, thymus, breast, lung, stomach, heart, brain, kidney, liver, skin, or testis. The antibody was also tested by indirect immunofluorescence against 17 samples of metastatic malignant melanoma which were removed from 13 patients. WI-MN-1 gave positive reaction against 16 of these specimens, and it reacted with the cryostat section in the immunoperoxidase test, delineating neoplastic melanoma from the normal brain tissue. The antibody precipitated Mr 105,000 and 38,000 antigens from biosynthetically labeled G-361 cells. It was suggested that WI-MN-1 was a useful addition to the panel of monoclonal antibodies against melanoma-associated antigens.