Ontology highlight
ABSTRACT: Objective
CD4+FoxP3+CD25+ regulatory T-cells (Tregs) are important for preventing tissue destruction. Here, we investigate the role of Tregs for protection against experimental arthritis by IFN-?.Methods
Arthritis was triggered by intra-articular injection of methylated bovine serum albumin (mBSA) in wild-type mice, Foxp3DTReGFP+/- mice [allowing selective depletion of Tregs by diphtheria toxin (DT)] and CD4-Cre+/- IFNA1R flox/flox mice (devoid of IFNAR signaling in T-cells) earlier immunized with mBSA, with or without treatment with IFN-? or the indoleamine 2,3-dioxygenase (IDO)-metabolite kynurenine. Tregs were depleted in DT-treated Foxp3DTReGFP+/- mice and enumerated by FoxP3 staining. Suppressive capacity of FACS-sorted CD25+highCD4+ Tregs was tested in vivo by adoptive transfer and ex vivo in cocultures with antigen-stimulated CFSE-stained T-responder (CD25-CD4+) cells. IDO was inhibited by 1-methyl tryptophan.Results
Both control mice and mice devoid of IFNAR-signaling in T helper cells were protected from arthritis by IFN-?. Depletion of Tregs in the arthritis phase, but not at immunization, abolished the protective effect of IFN-? and kynurenine against arthritis. IFN-? increased the number of Tregs in ex vivo cultures upon antigen recall stimulation but not in naïve cells. IFN-? also increased the suppressive capacity of Tregs against mBSA-induced T-responder cell proliferation ex vivo and against arthritis when adoptively transferred. The increased suppressive activity against proliferation conferred by IFN-? was clearly reduced by in vivo inhibition of IDO at immunization, which also abolished the protective effect of IFN-? against arthritis.Conclusion
By activating IDO during antigen sensitization, IFN-? activates Tregs, which prevent arthritis triggered by antigen rechallenge. This is one way by which IFN-? suppresses inflammation.
SUBMITTER: Chenna Narendra S
PROVIDER: S-EPMC5826073 | biostudies-literature | 2018
REPOSITORIES: biostudies-literature
Frontiers in immunology 20180219
<h4>Objective</h4>CD4<sup>+</sup>FoxP3<sup>+</sup>CD25<sup>+</sup> regulatory T-cells (T<sub>regs</sub>) are important for preventing tissue destruction. Here, we investigate the role of T<sub>regs</sub> for protection against experimental arthritis by IFN-α.<h4>Methods</h4>Arthritis was triggered by intra-articular injection of methylated bovine serum albumin (mBSA) in wild-type mice, Foxp3DTReGFP<sup>+/-</sup> mice [allowing selective depletion of T<sub>regs</sub> by diphtheria toxin (DT)] and ...[more]