The existence of a common lymphoid progenitor that can only give rise to T cells, B cells, and natural killer (NK) cells remains controversial and constitutes an important gap in the hematopoietic lineage maps. Here, we report that the Lin−IL-7R+Thy-1−Sca-1loc-Kitlo population from adult mouse bone marrow possessed a rapid lymphoid-restricted (T, B, and NK) reconstitution capacity in vivo but completely lacked myeloid differentiation potential either in vivo or in vitro. A single Lin−IL-7R+Thy-1−Sca-1loc-Kitlo cell could generate at least both T and B cells. These data provide direct evidence for the existence of common lymphoid progenitors in sites of early hematopoiesis.

Identification of Clonogenic Common Lymphoid Progenitors in Mouse Bone Marrow