Molecular events that regulate alpha beta versus gamma delta T cell lineage commitment: old suspects, new players and different game plans

The divergence of alpha beta and gamma delta T cells from a common precursor in the thymus is regulated by multiple cell-intrinsic and cell-extrinsic factors, most of which are not well defined. Recent studies have provided crucial data regarding the precise timing of lineage commitment and some clarification on the extent of the involvement of Notch and T-cell receptor signaling in this process. Combined with new insights into the differential regulation of molecular pathways active in alpha beta and gamma delta. precursors, these data have led to the generation of a revised model of lineage commitment.