CD117, CD200 and CD371 identifies seven populations of ?d thymocytes programmed towards three distinct effector subsets in adult mice

Murine ?d T cells include several effector subsets that fulfil distinct functional roles. In pathological conditions, such as cancer, some ?d T cell subsets are highly protective whereas other subsets may exacerbate disease. ?d T cells are programmed for their effector function during their development in the thymus. Investigations of ?d T cell development have been hampered by the scarcity of surface markers distinguishing different development stages. In this study, we found that addition of CD117, CD200 and CD371 to existing markers, allowed identification of seven distinct development stages (named A, B, C, D, E, F and G) present in both the V?1.1+ and V?2+ thymocyte subsets. We provide evidence for the existence of three distinct pathways leading to export of ?d T cells, two of which express high levels of CD24. These pathways are dominated by different TCRd repertoires shaped by TCR signalling or lack thereof. Each pathway express distinct cytokine and transcription factor profiles associated with ?dT1, ?dNKT and adaptive ?d T cells. Thus, the identification of additional ?d T cell development stages in this study connects three distinct development pathways to the programming of three ?d T cell effector subsets. Overall design: FACS sorted TCRV?1.1+ and TCRV?2+ ?d thymocytes each divided into 7 populations based on expression of CD24, CD25, CD73, CD117, CD200 and CD371 pooled from 3x8 (rep1) or 2x8 (rep2) mice. Two biological replicates (rep1 and rep2).