A synthetic agent derived from the tumor-associated differentiation antigen gp100 DNA. Gp100 DNA is coated onto microscopic gold beads and used to immunize animals and generate polyclonal antibodies that specifically recognize gp100 antigen. Gp100 human antigen is a non-mutated self-antigen - glycoprotein -expressed by melanocytes, pigmented retinal cells and most melanoma lesions, but is not expressed in other normal tissues or non-melanoma tumors. Immunization with human gp100 DNA may induce protective immunity against melanoma and may provide an effective approach for vaccine therapy with tumor-associated antigens against human melanoma. (NCI04) [ ]