Identification and follow-up of homologous and heterologous bone-marrow transplants in radiation-chimeras

Using differences in the electrophoretic pattern between host and donor haemoglobins, the proliferation of grafted erythropoietic cells has been studied in irradiated mice treated with homologous bone marrow. The results have been compared with observations made after the transplantation of rat bone marrow into irradiated mice. A complete replacement of host erythrocytes by donor-type cells took 60-70 days in mice treated with rat bone marrow. In mice treated with homologous bone marrow, host-type haemoglobin could no longer be identified after about 50 days. In the latter case the complete replacement must have taken somewhat longer, since the method used to identify haemoglobins is not sensitive enough to detect small amounts of one type of haemoglobin in the presence of large amounts of the other. In mice treated with rat bone marrow a considerable number of total and partial reversals occurred after 675-700 r. Only a few partial reversals were found after 800 r. Under similar conditions no reversals were observed after homologous bone-marrow transplantation. It is concluded that the recovery of the host's haematopoietic system depends upon the dose of radiation as well as on the antigenic difference between the host and the donor. © 1959 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted