Tumor Resistance Induced by Syngeneic Bone Marrow Transplantation and Enhanced by Interleukin 2: A Model for the Graft versus Leukemia Reaction

Lethally irradiated C3H/HeN mice reconstituted with normal syngeneicbone marrow survived significantly longer than unmanipulatedcontrol mice following challenge with a lethal dose of 38C13 lymphomacells 2 to 3 weeks post-bone marrow transplantation (BMT). Althoughthe magnitude of this effect was modest, it was highly reproducible. Thisresistance-producing effect of BMT could be enhanced by interleukin 2administration and could be abrogated by anti-asialo-GM| antiserumtreatment of recipients. These findings are consistent with the hypothesis that cells with a natural killer phenotype are activated by BMT andcan mediate tumor resistance. These studies provide a model to explorethe cellular basis, independent of donor alloreactivity, of the graft antitumoreffect of BMT observed in humans.