Studies on purification of antibodies against tumor-specific antigens.

The in vitro cytotoxic effect of anti Sarcoma I sera tumor cells in the presence of an exogenous source of complement was studied. The immune sera were obtained from xenogeneic and allogeneic animals, rabbits and mice, after injections with viable Sarcoma I tumor cells. Antibodies against mouse specific antigens were removed from the rabbit serum, by extensive absorption with mouse erythrocytes and lymphocytes. The absorbed serum was cytotoxic for Sarcoma I tumor cells and did not show any cytotoxicity for A/Jax lymphocytes. The antiserum was purified by an immunoabsorbent column using G-100 Sephadex conjugated with Sarcoma I tumor cell stroma. The eluted, purified antibodies were cytotoxic in vitro. Immunoelectrophoresis and immunodiffusion tests showed the presence of immunoglobulin in the purified antibody preparation. There was a hundred-fold increase of the specific activity of the purified antibodies as compared to the non-purified serum.