mKLRL1 regulates the maturation of dendritic cells and plays important roles in immune tolerance.

KLRL1 is a member of C-type lectin-like receptors (CLEC) and preferentially expressed on the surface of immune cells. We have previously illustrated its inhibitory role in Natural killer (NK) cells. Though cloned from dendritic cells (DCs), its role in DCs has not been fully identified. Here, we found that mKLRL1 markedly decreased during DC maturation; mKLRL1-modifed DCs showed enhanced phagocytic capability and reduced ability to induce T cell proliferation, which mimics immature DCs. Further investigation revealed that IL-10 was indispensable for mKLRL1 to suppress DC maturation. And p38 activation was responsible for preferential IL-10 production. Pretreatment with mKLRL1-modified DCs protected mice from subsequently EAE induction, indicating a role in immune tolerance. Taken together, our results have revealed an inhibitory role of KLRL1 in mouse DCs.