Early T cell development and the pitfalls of potential.
The long-standing model for hematopoiesis, which features a dichotomy into separate lymphoid and myeloid branches, predicts that progenitor T cells arise from a lymphocyte-restricted pathway. However, experiments that have detected myeloid potential in progenitor T cells have been reported as evidence to question this model. Mapping physiological differentiation pathways has now led to opposite conclusions, by showing that T cells and thymic myeloid cells have distinct origins and that, in vivo, T cell progenitors lack significant potential for myeloid lineages including dendritic cells. Here, we review the underlying experiments that have led to such fundamentally different conclusions. The current controversy might reflect a need to distinguish between cell fates that are possible experimentally from physiological fate choices, to build a map of immunological differentiation pathways.
Schlenner
Susan M
SM
Department for Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
Rodewald
Hans-Reimer
HR
D000818:Animals; D001853:Bone Marrow / Q000276:immunology; D019070:Cell Lineage; D006410:Hematopoiesis; D006801:Humans; D051880:Receptors, Notch / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology
D051880:Receptors, Notch