title: Bacterial CD1d-restricted glycolipids induce IL-10 production by human regulatory T cells upon cross-talk with invariant NKT cells.
abstract: Invariant NKT (iNKT) cells and CD4(+)CD25(+)FOXP3(+) regulatory T cells (Tregs) are important immune regulatory T cells with Ag reactivity to glycolipids and peptides, respectively. However, the functional interplay between these cells in humans is poorly understood. We show that Tregs suppress iNKT cell proliferation induced by CD1d-restricted glycolipids, including bacterial-derived diacylglycerols, as well as by innate-like activation. Inhibition was related to the potency of iNKT agonists, making diacylglycerol iNKT responses very prone to suppression. Cytokine production by iNKT cells was differentially modulated by Tregs because IL-4 production was reduced more profoundly compared with IFN-γ. A compelling observation was the significant production of IL-10 by Tregs after cell contact with iNKT cells, in particular in the presence of bacterial diacylglycerols. These iNKT-primed Tregs showed increased FOXP3 expression and superior suppressive function. Suppression of iNKT cell responses, but not conventional T cell responses, was IL-10 dependent, suggesting that there is a clear difference in mechanism between the Treg-mediated inhibition of these cell types. Our data highlight a physiologically relevant interaction between human iNKT and Tregs upon pathogen-derived glycolipid recognition that has a significant impact on the design of iNKT cell-based therapeutics.
authors.affiliation: Laboratory for Molecular Immunology and Inflammation, Department of Rheumatology, Faculty of Medicine and Health Sciences, Ghent University, 9000 Ghent, Belgium.
authors.forename: Koen
authors.initials: K
authors.lastname: Venken
authors.forename: Tine
authors.initials: T
authors.lastname: Decruy
authors.forename: Sandrine
authors.initials: S
authors.lastname: Aspeslagh
authors.forename: Serge
authors.initials: S
authors.lastname: Van Calenbergh
authors.forename: Bart N
authors.initials: BN
authors.lastname: Lambrecht
authors.forename: Dirk
authors.initials: D
authors.lastname: Elewaut
mesh_terms: D055610:Antigens, CD1d / Q000276:immunology; D018920:Coculture Techniques; D005434:Flow Cytometry; D006017:Glycolipids / Q000276:immunology*; D006801:Humans; D016753:Interleukin-10 / Q000096:biosynthesis / Q000592:standards*; D008213:Lymphocyte Activation / Q000276:immunology*; D055611:Natural Killer T-Cells / Q000276:immunology* / Q000378:metabolism; D020239:Receptor Cross-Talk / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism
chemical_list: D055610:Antigens, CD1d; C526877:CD1D protein, human; D006017:Glycolipids; C508609:IL10 protein, human; D016753:Interleukin-10