Report Date:

Abstract:

Gut homeostasis and mucosal immune defense rely on the differential contributions of dendritic cells (DC) and macrophages. Here we show that colonic CX3CR1(+) mononuclear phagocytes are critical inducers of the innate response to Citrobacter rodentium infection. Specifically, the absence of IL-23 expression in macrophages or CD11b(+) DC results in the impairment of IL-22 production and in acute lethality. Highlighting immunopathology as a death cause, infected animals are rescued by the neutralization of IL-12 or IFNgamma. Moreover, mice are also protected when the CD103(+) CD11b(-) DC compartment is rendered deficient for IL-12 production. We show that IL-12 production by colonic CD103(+) CD11b(-) DC is repressed by IL-23. Collectively, in addition to its role in inducing IL-22 production, macrophage-derived or CD103(-) CD11b(+) DC-derived IL-23 is required to negatively control the otherwise deleterious production of IL-12 by CD103(+) CD11b(-) DC. Impairment of this critical mononuclear phagocyte crosstalk results in the generation of IFNgamma-producing former TH17 cells and fatal immunopathology.

Notes:

Aychek, TegestMildner, AlexanderYona, SimonKim, Ki-WookLampl, NardyReich-Zeliger, ShlomitBoon, LouisYogev, NirWaisman, AriCua, Daniel JJung, SteffenengResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, Non-P.H.S.EnglandNat Commun. 2015 Mar 12;6:6525. doi: 10.1038/ncomms7525.