The role of the T‐cell receptor (TCR) in αβ/γδ lineage commitment: clues from intracellular TCR staining

Summary: T cells belong to two mutually exclusive lineages expressing either αβ orγδ T‐cell receptors (TCR). Although αβ and γδ cells are known to share a common precursor the role of TCR rearrangement and specificity in the lineage commitment process is controversial. Instructive lineage commitment models endow the αβ or γδ TCR with a deterministic role in lineage choice, whereas separate lineage models invoke TCR‐independent lineage commitment followed by TCR‐dependent selection and maturation of αβ and γδ cells. Here we review the published data pertaining to the role of the TCR in αβ/γδ lineage commitment and provide some additional information obtained from recent intracellular TCR staining studies. We conclude that a variant of the separate lineage model is best able to accommodate all of the available experimental results.