Serological detection of common human melanoma membrane antigens by microcomplement fixation and immunofluorescence

An antiserum to human melanoma antigens was obtained from a melanoma patient after immunization with autologous irradiated cultured melanoma cells and bacillus Calmette-Guerin. Using the microcomplement fixation assay, the antiserum, at a titer of 1/1,800, was noted to bind strongly with 7 of 10 allogeneic cultured human melanoma cells lines. However, using the indirect immunofluorescence test and serum at a much lower titer (1/8), only 3 of the 10 melanoma cell lines were positive. Using both microcomplement fixation and indirect immunofluorescence, no significant reactivity was noted in several nonmelanoma cell lines including Hela, human lung adenocarcinoma, human prostatic carcinoma, WI-38 and VA-13 cell lines. These data suggest that common melanoma membrane antigens exist on 7 of 10 cultured human melanoma cell lines as tested by microcomplement fixation and that this assay is more sensitive than immunofluorescence. These common melanoma membrane antigens may eventually be extracted, purified and used for specific immunodiagnosis and immunotherapy.