Lineage Tracking Dissects the Fate of Neonatal iNKT Cells Later in Life

Invariant natural killer T (iNKT) cells in peripheral tissues are from different waves ranged from foetal, neonatal to adult ages. However, it is unclear how iNKT cells from different ages maintain in the periphery and what are their functionality. We found that in adult mice, neonate tracked-iNKT (NT-iNKT) cells are present in spleen, bone marrow, liver and lung, with a predominantly accumulation in the kidney. The NT-iNKT cells in the kidney are almost iNKT1 cells and express tissue-resident marker CD69. These cells also exhibit higher level of CD122 and possess a stronger proliferative capacity compared to adult tracked-iNKT (AT-iNKT) cells. Furthermore, we found that NT-iNKT cells potentially secrete more IFN-γ than AT-iNKT cells in vitro and in vivo (a-GalCer immunisation). Overall, our study sheds light on the peripheral behaviour and functionality of NT- and AT-iNKT cells, highlighting the potential role of NT-iNKT cells in the kidney during immune response.