B-lymphopoiesis gains sensitivity to subsequent inhibition by estrogens during final phase of fetal development.

Adult B-lymphopoiesis is suppressed by the inhibitory effects of elevated estrogens during pregnancy. At the same time, hematopoietic cells in the fetal liver are resistant to this suppression by estrogens and ensure active production of B-cells. We investigated whether this unresponsiveness to estrogens of fetal cells also applies to cells obtained from a newborn liver and projects into the adult hematopoiesis when fetal liver cells are transplanted to adult mice.