JAK2 and Autoimmunity: Herein, we report that depletion of Optn in mice by CD11c-Cre promotes JAK2-STAT3 phosphorylation and the forming of IL-10/JAK2/STAT3/IL-10 positive feedback loop, thus impairing DC maturation and the priming of CD4+ T cells to prevent the development of autoimmunity in mice.