Invariant NKT cell development: focus on NOD mice

•iNKT cells develop in the thymus and are selected by CD1d expressing thymocytes.•The expression of different markers allowed identifying three stages of development.•iNKT1, iNKT2 and iNKT17 cells are classified by their cytokine expression profile.•iNKT cell subsets have a heterogeneous distribution among different murine strains.•The subsets of iNKT cells play distinct roles during immune mediated pathologies.

Natural killer T (NKT) cells are non-conventional T lymphocytes expressing a TCRαβ and several NK cell markers. Once activated, they can rapidly secrete large amounts of cytokines such as IFN-γ and IL-4. As a result they can favor both Th1 and Th2 immune responses and play a critical role in anti-pathogenic immune responses as well as in regulation of autoimmune diseases. It has now been clearly established that iNKT cells can be subdivided into three subpopulations: iNKT1, iNKT2 and iNKT17 cells. Each of these populations is characterized by the expression of a particular transcription factor, surface markers and cytokines making them functionally distinct. Interestingly, NOD mice developing autoimmune diabetes exhibit a high frequency of iNKT17 cells, which can participate in the disease.