T cell fate specification and alpha beta/gamma delta lineage commitment

The development of T cells from pluripotent stem cells involves a coordinat ed series of lineage-commitment steps. Common lymphoid precursors in the fe tal liver or adult bone marrow must first choose between T, B or NK cell fa te. Committed T cell precursors in the thymus then differentiate into cells committed to the alpha beta or gamma delta lineages. Recent advances have been made in our understanding of the mechanisms underlying T cell fate spe cification and alpha beta/gamma delta lineage divergence.