Purification of cell line-specific transplantation antigens from mouse ascites tumor cells

Tumor-specific transplantation antigens unique to each of MM2, MM46 and Ehrlich mouse ascites tumor cells (cell line-specific antigens) were released from the cells into the medium during incubation in 0.12M saline at 37 degrees for 30 min. The released antigens were purified by identical procedures which consisted of ultracentrifugation, affinity chromatography using Sepharose 4B conjugated with Ricinus communis lectin, and DEAE-cellulose column chromatography. The recovery was about 700 micrograms (protein) from 100 g (wet weight) cells. The recovered materials induced specific immunity in C3H/He mice against transplantation of the corresponding tumor cells only when they were administered after treatment with the corresponding tumor-regressor C3H/He mouse serum. Single injection into the peritoneal cavity of 10 mcrograms of each of the pretreated materials inhibited transplantation of 5 x 10(3) corresponding tumor cells. Spleen cells from mice immunized by repeated injections of the pretreated antigen neutralized transplantability of the tumor cells. Specific humoral antibody was also detected. The specific antigens obtained from these cells were similar to each other with respect to sedimentation coefficient (16S), electrophoretic characteristics and xenogeneic antigenicity, and were free of beta-2 microglobulin, murine leukemia virus major structural proteins such as gp70 or p30 and murine mammary tumor virus proteins such as gp55 and p28.