Self-reactivity shapes functional diversity of naive CD8+ T cells by co-opting tonic type I interferon [Array]

The strength of the T cell receptor interaction with self-ligands affects antigen-specific immune responses. However, the precise role, functional relationship, and underlying mechanisms have not been elucidated completely. Here, we demonstrate that naive CD8+ T cells with relatively high self-reactivity are phenotypically heterogeneous owing to varied responses to type I interferon (T1IFN), resulting in three distinct subsets, CD5loLy6C–, CD5hiLy6C–, and CD5hiLy6C+ cells. CD5hiLy6C+ cells differ from CD5loLy6C– and CD5hiLy6C– cells in their gene expression profiles and functional properties. Moreover, CD5hiLy6C+ cells demonstrate more extensive antigen-specific expansion upon viral infection, with enhanced differentiation into terminal effector cells and reduced memory cell generation. Such unique features of CD5hiLy6C+ cells are imprinted in a steady-state and observed even for those of monoclonal CD8+ T cell populations in a T1IFN dependent fashion. These findings demonstrate that self-reactivity shapes the functional diversity of naive CD8+ T cells by co-opting tonic T1IFN signaling. Gene profiles of 3 naive (CD44lo) CD8+ T cell subsets (CD5lo, CD5hi Ly6C-, and CD5hi Ly6C+)