Surface antigens on cultured malignant melanoma cells as detected by a membrane immunofluorescence method with human sera. Lack of tumor-specific reactions on melanoma lines.

Surface antigens on melanoma cells were studied with an MIF method applied for monolayers of cultured cells. Human sera were used with indirect immunofluorescence. Preparations were fixed in methanol after staining. Reactions of sera with antibodies against trasplantation antigens displayed a fine granular fluorescence. This appearance was abolished by absorptions with pooled tonsilar lymphocytes. Melanoma patients' sera free from antibodies against transplantation antigens exhibited a coarse patchy fluorescence reaction. Melanoma patients' sera with antibodies against transplantation antigens yielded the second type of MIF reaction after absorptions with normal lymphocytes whereas further absorptions with melanoma line suspensions effectively removed all antibody reactivity...