An immunogen consisting of a 4M urea extract derived from human melanoma cells (M14), that was devoid of HLA-A,B,C, HLA-DR antigens and fibronectin was adsorbed to lens culinaris lectin-Sepharose 4B and used to immunize mice for production of monoclonal antibody to a melanoma-specific glycoprotein. Screening for hybridomas secreting antibodies to melanoma associated antigens was facilitated by use of a solid phase target antigen of chemically defined medium of melanoma cells (CDM). Use of these procedures allowed us to select 40 hybridomas secreting antibody which recognized determinants on melanoma cells not found on lymphoid cells. Further characterization of one of these hybridomas, 9.2.27, indicated that the antibody it secreted recognized a 240K dalton glycoprotein found on all melanoma cell lines tested but not on carcinoma, lymphoid, or fibroblastoid cultures. These results demonstrate the utility of soluble antigen preparations devoid of strongly immunogenic non tumor-specific molecules in the elicitation of tumor specific antibody. Preliminary results suggest that immunogens of this kind are superior to intact melanoma cells for production of tumor specific hybridomas.