Bone marrow cells other than stem cells seed the bone marrow after rescue transfusion of fatally irradiated mice

In a previous publication, iodinated deoxyuridine (125IUdR) incorporation data were interpreted as indicating that spleen colony-forming units (CFU-S) in DNA synthesis preferentially seeded bone marrow. In the present studies, the CFU-S content of marrow from irradiated, bone-marrow transfused mice was directly determined. Pretreatment of the transfused cells with cytocidal tritiated thymidine resulted in an insignificant diminution in CFU-S content when compared with nontritiated thymidine pretreatment, implying that there is no preferential seeding. The 125IUdR incorporation data have been reinterpreted as being a result of the proliferation of other progenitor cells present that have seeded the bone marrow