Detection by immunofluorescenge of antibodies specific for human malignant melanoma cells

Cells were separated from tissue specimens of human malignant melanoma and grown in tissue culture on coverslips. After 8 days of growth the explanted cells were fixed and stored until used. Sera from 15 patients with malignant melanoma were reacted with the fixed melanoma cells and a variety of other cells. The indirect immunofluorescence method was used to test for presence of antibodies. Sera from all 15 melanoma patients reacted with fixed melanoma cells giving intense fluorescence of intracytoplasmic granules. The fluorescent material appeared to be independent of melanin granules. Homogenate of fresh melanoma but not of other neoplastic or normal tissue absorbed out the anti-melanoma antibodies. The human antimalignant melanoma antibodies did not react with live malignant melanoma cells or with fixed or live cells from benign nevi or fixed guinea pig kidney, human kidney or HeLa cells. The evidence suggests that these antibodies are unable to penetrate living cell membranes.