In vivo delayed hypersensitivity reactions to partially purified human melanoma antigens

Sera from patients receiving autologous cell immunization were shown to contain antibody specific for melanoma cells by immunofluorescence, microcomplement fixation, and mixed hemadsorption. These hyperimmune specific sera were used to define antigens shed into tissue culture media from human malignant melanoma cells. When supernatants from cultured melanoma cells were passed over a Sephadex G-200 column, melanoma antigens were found in Peak 2. The active fraction was further purified by carboxymethylcellulose ion exchanger and found in the 0.4 M NaCl gradient. This fraction has been tested in four immunized patients and in one nonimmunized melanoma patient. All five patients developed lymphocytic vasculitis compatible with delayed hypersensitivity reaction. These antigens should be of benefit in studying delayed hypersensitivity in melanoma patients and as potential agents for specific immunotherapy.