Control of intestinal inflammation by regulatory T cells Fiona Powrie Sir William Dunn School of Pathology University of Oxford fiona.powrie@path.ox.ac.uk
Regulatory T cells prevent immune pathology in the intestine non-inflammatory DC Infection Inflammation T E activity DC inflammatory Foxp3 T R IL-10, TGF-β T R activity T Suppression X T E 1. Mechanisms of T R mediated suppression of colitis 2. Identification of the gut as a site of T R generation-role of specialised DC
Regulatory T Cells 1. Naturally occurring T R (CD4 + CD25 + Foxp3 + ) Foxp3 necessary for development and function Mutations in Foxp3 gene cause lethal multi-organ inflammatory condition Suppress response to self & foreign Ag: Autoimmunity Immunity to infection Allergy Tumour immunity IBD Transplant rejection 2. Adaptive/Induced T R IL-10, TGF-b, Foxp3 Thymus Periphery CD4 + CD25 + Foxp3 + CD4 + CD25 + Foxp3 + CD4 + Foxp3 - CD4 + Foxp3 - IL-10 Foxp3 TGF-b
T R cells prevent colitis CD4 + CD45RB hi X colitis CD4 + CD45RB low CD25 + Prevention of colitis involves IL-10, TGF-beta and CTLA4 T R cells prevent accumulation of activated DC Directly suppress the innate response via IL-10 production CD4 CD11c DAPI Powrie et al., JEM 1994, Read et al., JEM 2001, Maloy et al,. JEM 2003
T R cells cure colitis CD4 + CD45RB hi CD45.2 CD4 + CD25 + CD45.1 RAG -/- 4wk 2wk (early) 10wk (cured) T R cells cure established colitis. Proliferate in MLN and colon in close contact with T E and DC Dependent on IL-10 Uhlig et al, JI, 2006; Mottet et al., JI 2003
Regulatory T cells in the intestine produce IL-10 Spleen Colon 0.3 2.7 0.7 26.6 IL-10 Foxp3 Uhlig et al, JI, 2006
Ag exposure in the gut induces tolerance Apoptotic IEL Luminal Ag IL-10 Constitutive Migration Gut Homing IL-10
Oral administration of ovalbumin induces Foxp3 + T cells from naïve precursors OVA BSA OVA BSA 1.30 0.14 Foxp3 DO11.10 SCID 5d CD4 MLN, Spleen, Colon LP
CD103 a marker of gut DC αe integrin subunit Expressed by mucosal DC and T Cells DC Pairs with β7, binds to E-cadherin on epithelial cells E-cadherin alphae (CD103) beta7 Gated on CD11c high Annacker et al., JEM 2005, Lindbom et al., 2005
Functional properties of CD103 + DC CD103 + CD103 - Naïve T cell Proliferation ++ ++ IFN-gamma - + Inflammatory Cytokines (IL-6, IL-23) - + Imprint gut homing Receptors ++ - CD103 expression in RAG-/- required for T R activity Annacker et al., JEM 2005; Coombes et al., JEM 2007
Sorting DC for in vitro T cell differentiation assay MLN CD11c MACS CD103 + and CD103 - subsets sorted on MoFlo CD11c Balb/c CD103 CD103+ CFSE Naïve D011.10/SCID CD4 + T analysis analysis cytokines CD103- + OVAp d4 IL-2 d7 αcd3 d8
CD103 + DC promote the expression of Foxp3 by naïve T cells CD103+ CD103- DC Foxp3 CD103 Proliferation Cytokines? T Regulatory Properties? Homing % Foxp3 + p Foxp3 9 8 7 6 5 4 3 2 1 0 CFSE CD4 CD103- CD103+ 1x10^5 0.5x10^5 0.25x10^5
TGF-β-mediated induction of Foxp3 is increased in the presence of CD103 + DC 50 40 CD103+ CD103- % Foxp3+ 30 20 10 0-0.1ng/ml 1ng/ml [TGF-β] Induction of Foxp3 by CD103 + DC is TGF-β dependent
CD103 + DCs express higher levels of retinal dehydrogenase than CD103 - DCs Cellular Retinoid Metabolism Retinol (Vitamin A) ADHs SDR Retinal ALDH1A1 ALDH1A2 ALDH1A3 Relative expression/hprt 50 40 30 20 10 0 aldh1a2 CD103 + CD103 - Retinoic Acid Mucosal epithelial cells and CD11c + DCs in the dome areas of the small intestine express ALDH1A1, whilst MLN-DCs express ALDH1A2 (Iwata et al., Immunity, 2004)
Retinoic acid acts as a co-factor for Foxp3 induction + TGF-β + TGF-β/RA p<0.001 CD103 + 60 ns beta7 % Foxp3 + 40 20 p<0.001 CD103-0 CD103 + CD103 - CD103 + +RA CD103 - +RA Foxp3 Spontaneous induction of Foxp3 in the presence of CD103 + DC is inhibited by an RAR antagonist Foxp3+ cells suppress T cell proliferation in vitro (Yasmine Belkaid, Jason Hall) Coombes et al., 2007; Hall et al., 2007; Benson et al. 2007; Murcida et al 2007
Summary Natural T R cells respond to inflammation and cure established colitis Compartmentalisation of the T R response-key role of IL-10 in control of tissue inflammation Gut is a site that favours induction of Foxp3+T R cells GALT contains functionally specialised CD103 + DC CD103 + DC imprint gut homing receptors on T cells and induce FoxP3 expression by a TGF-β and RA dependent mechanism A mechanism to broaden the repertoire of T R cells responding to intestinal antigens In addition to natural T R cells, induced T R may play an important role in intestinal homeostasis
CD103+ DC: mucosal DC that support the development of Foxp3+ T R cells with a mucosal seeking phenotype Colon MLN Gut conditioning TGF-β, Vit A DC E-cadherin DC CD103? TGF-β RA CD103 T Foxp3 IFNγ CCR9
Complimentary therapies for intestinal inflammation? Dysregulated responses M N N N IL-17 TNF-α IL-6 IFN-γ DC IL-23 Th1 Th1 Th1 Tn IL-10 TGF-β Ab blockade Treg Treg Treg T R activity Treg Foxp3+
Acknowledgements SWDSP: Chris Mottet Holm Uhlig Oliver Annacker Ana Izcue Janine Coombes Sophie Hue Sophia Buonocore Karima Siddiqui Kevin Maloy NIH Yasmine Belkaid Jason Hall Wellcome Trust MRC EU