title: Effects of pre-irradiation on isogeneic and semi-isogeneic CFU growth: a study on genetic resistance.
abstract: The genetic resistance to a parental bone marrow transplant as demonstrated, when transplantation was performed early after irradiation, failed to occur if the interval between irradiation and transplantation was increased to 4 days. A similar radiation induced weakening of genetic resistance to a parental bone marrow graft in spleen and bone marrow could be demonstrated in mice, which had been irradiated with a sublethal dose at 7 days prior to the lethal irradiation and transplantation. The pre-irradiation of the recipient with a sublethal dose induced an enhancement of the growth in spleen and bone marrow of isogeneic transplanted CFU. The pre-irradiation of a single tibia also resulted in a significant weakening of the resistance in the spleen. The experiments with partial body pre-irradiation suggested a local effect of the pre-irradiation, but it could be shown that the enhanced CFU growth is not caused by an enhanced seeding of CFU in pre-irradiated bone marrow. The role of microenvironment in the phenomenon of genetic resistance is discussed.
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000528:radiation effects*; D001854:Bone Marrow Cells; D016026:Bone Marrow Transplantation; D002455:Cell Division / Q000528:radiation effects; D007125:Immunogenetics; D051379:Mice; D013154:Spleen / Q000166:cytology; D013997:Time Factors; D014181:Transplantation Immunology / Q000528:radiation effects*; D014185:Transplantation, Isogeneic; D014965:X-Rays