Radiation leukemogenesis: quantitative relationship between pre-leukemic cells in the thymus and lymphoma induction.
Fractionated irradiation of C57BL/6 mice induces a population of pre-leukemic (PL) cells that progress into mature thymic lymphomas after a latency of 4 to 6 months. Transfer of graded numbers of thymocytes from an irradiated mouse into recipient mice indicated that PL cells first appear in the thymus 6 weeks after irradiation. The initial proportion of the thymic PL cells is > or = 10(-5) and their frequency continuously increases with time, reaching > or = 10(-3) 10 weeks after irradiation. The PL cell population that emerges early during the pre-malignant latency consists of pleioclonal T lymphocytes. However, within 4 weeks a dominant PL clone can be detected which becomes the progenitor of a clonal lymphoma 9 to 15 weeks later. These results suggest that radiation leukemogenesis involves continuous accumulation of pleioclonal PL cells in the thymus, one of which is then selected for further maturation into frank lymphoma.
Kotler
M
M
Department of Molecular Genetics, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Ruchlemer
R
R
Avni
O
O
Yefenof
E
E
D000818:Animals; D005260:Female; D007953:Leukemia, Radiation-Induced; D008223:Lymphoma / Q000209:etiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009368:Neoplasm Transplantation; D011289:Preleukemia / Q000209:etiology; D013950:Thymus Gland / Q000528:radiation effects*; D013997:Time Factors; D014916:Whole-Body Irradiation