Influence of antisera from histoincompatible mice on electrophoretic mobility of EL4 tumor cells.

was produced in a coisogenic B10.D2 (H^) strain of mice by intra|)oritoncal injection of the tissue preparations together with adjuvant. -/-Globulins were precipitated by ammonium sulfate and subfractions separated on Sephadex G-200. These were examined by microelectrophoresis for effects on surface charges of EL4 lymphoma cells and for hemolytic potency in tests with histoincompatible erythrocytes. The neoplastic cells elicited production of relatively large quantities of a tumor-specific antibody, which in the presence of active complement reduced the electrophoretic mobility of EL4 tumor cells, but which was inactive in the hemolytic test. This antibody could not be re moved by repeated treatment with normal tissue cells, but was absorbed sjiecifically by the tumor cells. In the mice given neo plastic cells there was produced a relatively small quantity of (presumably) H-2 isoantibodies of which one subfraction did not influence the mobility of tumor cells but showed hemolytic ac tivity, and of which another subfraction was active in both tests. The latter subfraction lost its mobility-reducing effect when heated to 58°Cfor 10 min. However, injection of normal tissues