Hemopoietic reconstitution obtained in F1 hybrids by grafting of parental marrow cells.

T-cell tolerance to CML and MLR determinants in tetraparental bone marrow chimeras, prepared by injecting lethally x-irradiated F1 hybrids with bone marrow cells from both parental strains, is most likely due to clonal deletion. Tolerance to CML, but not to the host's MLR, determinants is observed when lethally x-irradiated F1 hybrids are repopulated with bone marrow from one parental strain only. The results demonstrate that removal of T cells from donor cells, as well as exclusion of a HVG reaction, make it possible to transplant bone marrow between allogeneic individuals.