Competitive <i>in vivo</i> proliferation of foetal and adult haematopoietic cells in lethally irradiated mice

Abstract

Abstract The relative proliferative capacity of haematopoietic cell populations derived from 22‐week‐old adult bone marrow and 14–18 day foetal liver has been studied in lethally irradiated syngeneic recipients by means of chromosome markers. Although starting at a disadvantage in terms of the number of colony‐forming units (stem cells) injected, the foetal liver‐derived populations steadily increased their relative numbers in the myeloid and lymphoid tissues over a period of several weeks until a plateau was reached. It is suggested that stem cells in foetal liver have, on average, a higher intrinsic capacity for self‐renewal than do those in bone marrow, and that this capacity falls to the adult level within about ten weeks of transfer.