Tests for Isoantibodies Active in Conjunction with Guinea Pig Serum Against 6G3HED Lymphoma Cells. ∗

Summary

In the light of a previous observation—that normal guinea pig serum is highly effective against 6C3HED lymphoma cells in vivo but not in vitro, the host animal obviously participating in the reaction in vivo—a number of experiments were done to learn whether isoantibodies, capable of acting in conjunction with guinea pig serum against the lymphoma cells, might be present in the serum of normal mice of susceptible and resistant strains, in that of susceptible hosts carrying 6C3HED lymphomas, or in that of mice that had overcome implanted 6C3HED lymphoma cells and proved immune to re-implantation with them. The findings are given in some detail. They provide strong but not conclusive evidence that such isoantibodies are absent from the blood of mice in all the categories mentioned above. It follows that host factors or conditions of some other sort might profitably be sought to account for the participation by the host in the reaction whereby normal guinea pig serum, injected into animals carrying 6C3HED lymphomas, brings about death of the lymphoma cells.