Murine adult hematopoietic cells produce adult erythrocytes in fetal recipients

Bone marrow cells from normal adult mice were introduced by microinjection via the placenta into W/W^v genetically anemic fetuses of 11 days' gestation. After birth, erythrocytes were fractionated by fluorescence‐activated cell sorting on the basis of antibody binding to a fetal‐specific antigen (Ft). Lysates of Ft‐positive, i.e., fetal, erythrocytes did not detectably contain hemoglobin of the donor type, as judged from electrophoresis of strain‐specific hemoglobin variants. Thus, adult hematopoietic bone marrow cells did not resume fetal differentiation despite their post‐transplant maturation in a fetal environment.