[Method of isolation of cancer-associated and cancer-specific antigens]

Several biological and biochemical techniques are combined to get the isolation of tumor-specific and tumor-associated antigens (TSA and TAA). Specific antisera to plasma membrane TSA and TAA from the mouse Ehrlich ascites cancer (EAC) cells are induced by selective immunization of immunologic chimera rabbits to normal mouse antigens. The specific anti-cancer immunosera are absorbed with normal antigens to remove any possible residual normal antigens. The antibodies to TSA and TAA are purified by several cycles of discontinuous ascending chromatography in dextran gel particles, and used as a ligand for affinity chromatography in cyanide bromide-activated agarose gel. The material offered to the column consists of EAC cell plasma membrane fragments solubilized by ultrasonic waves, and isolated by discontinuous sucrose density gradient centrifugation. The marked cytotoxicity inhibition of antisera to EAC cells obtained by the TSA and TAA eluted from the affinity chromatography column, and the great immunogenicity of TSA and TAA in EAC-bearing animals show the existence of potent specific rejection antigens (TSRA and TARA) among the obtained TSA and TAA. The amount of TSA and TAA isolated from the EAC cell plasma membrane is 6 ng/10(6) cells, representing 1 part per 43,000 of the cell proteins.