Potential leukemic cells among bone marrow cells of young AKR/J mice.

Potentially leukemic cells have been identified among bone marrow cells of AKR/J mice from the age of 14 days onward. Transfer of AKR/J bone marrow into irradiated hybrid mice (AKR/J X DBA/2)F1 caused a high leukemia incidence (50-100%) of AKR origin, very often within a short latent period. Similar transfer of AKR/J marrow into irradiated AKR/J recipients did not enhance spontaneous tumor development. In contrast to the leukemic AKR cells that express the T-cell surface component Thy-1.1, the potential leukemic cells among bone marrow cells of young AKR mice were shown to lack the expression of this antigen. The development of preleukemic AKR marrow into overt leukemia in hybrid mice was dependent on the presence of an intact thymus and exposure of the recipients to x-rays shortly before marrow transfer. Evidently, preleukemic AKR bone marrow undergoes sequential changes, affected by host factors, leading ultimately to development of overt leukemia.