Critical role for invariant chain in CD1d-mediated selection and maturation of Vα14-invariant NKT cells

► We studied mice lacking Class II MHC chaperone Ii for iNKT cell thymic development. ► Mice lacking Ii show reduced iNKT cell thymic maturation. ► iNKT cells developed in Ii−/− mice no longer suppress Mtb pathogen replication. ► Mice lacking Ii have impaired cytokine production by iNKT cells. ► Ii is necessary in the periphery to support full maturation of iNKT cells.