Plasmacytoid dendritic cells license regulatory T cells, upon iNKT-cell stimulation, to prevent autoimmune diabetes.
Invariant NKT (iNKT)-cell stimulation with exogenous specific ligands prevents the development of type 1 diabetes (T1D) in NOD mice. Studies based on anti-islet T-cell transfer showed that iNKT cells prevent the differentiation of these T cells into effector T cells in the pancreatic lymph nodes (PLNs). We hypothesize that this defective priming could be explained by the ability of iNKT cells to induce tolerogenic dendritic cells (DCs) in the PLNs. We evaluated the effect of iNKT-cell stimulation on T1D development by transferring naïve diabetogenic BDC2.5 T cells into proinsulin 2(-/-) NOD mice treated with a long-lasting α-galactosylceramide regimen. In this context, iNKT cells induce the conversion of BDC2.5 T cells into Foxp3(+) Treg cells in the PLNs accumulating in the pancreatic islets. Furthermore, tolerogenic plasmacytoid DCs (pDCs) characterized by low MHC class II molecule expression and TGF-β production are critical in the PLNs for the recruitment of Treg cells into the pancreatic islets by inducing CXCR3 expression. Accordingly, pDC depletion in α-galactosylceramide-treated proinsulin 2(-/-) NOD mice abrogates the protection against T1D. These findings reveal that upon repetitive iNKT-cell stimulation, pDCs are critical for the recruitment of Treg cells in the pancreatic islets and the prevention of T1D development.
INSERM U1016, Institut Cochin, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France; Laboratoire d'Excellence INFLAMEX, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
Lucie
L
Beaudoin
Julien
J
Diana
Liana
L
Ghazarian
Yannick
Y
Simoni
Christian
C
Boitard
Agnès
A
Lehuen
D000818:Animals; D003713:Dendritic Cells / Q000276:immunology* / Q000473:pathology; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control; D007515:Islets of Langerhans / Q000276:immunology* / Q000473:pathology; D008198:Lymph Nodes / Q000276:immunology / Q000473:pathology; D051379:Mice; D016688:Mice, Inbred NOD; D018345:Mice, Knockout; D055611:Natural Killer T-Cells / Q000276:immunology* / Q000473:pathology; D010950:Plasma Cells / Q000276:immunology* / Q000473:pathology; D011384:Proinsulin / Q000235:genetics / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000473:pathology
D011384:Proinsulin
Diabetes; NKT; NOD; Plasmacytoid dendritic cells; Regulatory T (Treg) cells