RELATIONSHIPS BETWEEN IONIZING RADIATION,BONE MARROW TRANSPLANTATION AND LEUKEMOGENESIS

Studies of the relationships between ionizing radiation, bone marrow transplantation and leukemo-genesis were carried out in 343 LACA mice. The recipients （female） were given whole-body irradiationwith 7 or 8 Cy of Co-60 γ-rays, while the donors （male） were given whole-body irradiation with 3, 1.5,0.5, 0.1, 0.05 and 0 Gy of Co-60 γ-rays. Each recipient was intravenously infused with 1-3 ×10of themixed marrow cells of donors. In the result, the average incidence of surviving over 1 month was 86% inthe recipients. Myelocytic leukemia developed in all the transplanted groups, the average incidence being88.5%. Leukemia was observed in 1.5-2.5 months after transplantation in the recipients receiving marrowcells from donors exposed to 3 Gy, but in 5-8 months in other groups. It was demonstrated by the analysis of Y-chromosome that the leukemic cells were derived from the donor’s marrow cells. The resultssuggest that marrow transplantation for the mice irradiated by Co-60 γ-rays of lethal dose can prote