E3 Ubiquitin Ligase Cbl-b Restrains Priming of Pathogenic Th17 Cells Via the Inhibition of IL-6 Production by Macrophages

Abstract

E3 ubiquitin ligase Cbl-b is involved in the maintenance of a balance between immunity and tolerance. Mice lacking Cbl-b are highly susceptible to experimental autoimmune encephalomyelitis (EAE), a Th17-mediated autoimmune disease. However, how Cbl-b regulates Th17 cell responses remains unclear. In this study, utilizing adoptive transfer and cell type-specific Cblb knockout strains we show that Cbl-b expression in macrophages, but not T cells or dendritic cells (DCs), restrains the generation of pathogenic Th17 cells and the development of EAE. Cbl-b inhibits the production of IL-6 by macrophages induced by the signaling derived from C-type lectin receptors, which directs T cells to generate pathogenic Th17 cells. Therefore, our data are the first to unveil a previously unappreciated function for Cbl-b in the regulation of pathogenic Th17 responses.