Characterization of the developmental landscape of murine RORγt+ iNKT cells. Characterization of the developmental landscape of murine RORγt+ iNKT cells

Invariant natural killer T cells (iNKT) expressing the retinoic acid receptor-related orphan receptor γt (RORγt) and producing IL-17 represent a minor subset of CD1d-restricted iNKT cells (iNKT17) in C57BL/6J (B6) mice. We aimed in this study to define the reasons for their low distribution and the sequence of events accompanying their normal thymic development. We found that RORγt+ iNKT cells have higher proliferation potential and a greater propensity to apoptosis than RORγt- iNKT cells. These cells do not likely reside in the thymus indicating that thymus emigration, and higher apoptosis potential, could contribute to RORγt+ iNKT cell reduced thymic distribution. Ontogeny studies suggest that mature HSAlow RORγt+ iNKT cells might develop through developmental stages defined by a differential expression of CCR6 and CD138 during which RORγt expression and IL-17 production capabilities are progressively acquired. Finally, we found that RORγt+ iNKT cells perceive a strong TCR signal that could contribute to their entry into a specific Th17 like developmental program influencing their survival and migration. Overall, our study proposes a hypothetical thymic developmental sequence for iNKT17 cells, which could be of great use to study molecular mechanisms regulating this developmental program. Overall design: We investigate the transcriptional difference of iNKT cells between mice expressing from B6 mice vs Balbc mice Klibi J Li S Amable L Joseph C Brunet S Delord M Parietti V Jaubert J Marie J Karray S Eberl G, Lucas B Toubert A Benlagha K.