Control of intestinal inflammation by regulatory T cells

Fiona PowrieSir William Dunn School of

PathologyUniversity of Oxford

fiona.powrie@path.ox.ac.uk

Regulatory T cells prevent immune pathology in the intestine

DC DC

“non-inflammatory” “inflammatory”

X

InfectionInflammation

TE activity

IL-10, TGF-βTR activity

TE

Suppression

Foxp3TR

T

1. Mechanisms of TR mediated suppression of colitis2. Identification of the gut as a site of TR generation-role of specialised DC

Regulatory T Cells

1. Naturally occurring TR (CD4+CD25+Foxp3+)

Foxp3 necessary for development and functionMutations in Foxp3 gene cause lethal multi-organ inflammatory condition

Suppress response to self & foreign Ag:

AutoimmunityImmunity to infection Allergy Tumour immunity IBD Transplant rejection

2. Adaptive/Induced TR

IL-10, TGF-b, Foxp3

CD4+

CD25+

Foxp3+

CD4+

CD25+

Foxp3+

CD4+

Foxp3-CD4+

Foxp3-

IL-10

TGF-b

Foxp3

Thymus Periphery

Prevention of colitis involves IL-10, TGF-beta and CTLA4

TR cells prevent accumulation of activated DC

Directly suppress the innate response via IL-10 production

CD4 CD11c DAPIDAPI

TR cells prevent colitis

colitisXXCD4CD4++

CD45RBCD45RBhihi

CD4CD4++

CD45RBCD45RBlowlow

CD25CD25++

Powrie et al., JEM 1994, Read et al., JEM 2001, Maloy et al,. JEM 2003

RAG-/-

4wk2wk

(early)10wk

(cured)

CD4CD4++

CD45RBCD45RBhihiCD4CD4++

CD25CD25++CD45.2 CD45.1

TR cells cure colitis

TR cells cure established colitis. Proliferate in MLN and colon in close contact with TE 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

Uhlig et al , JI, 2006

0.3 2.7 0.7 26.6

Foxp3Foxp3

SpleenSpleen ColonColon

IL-1

0

Apoptotic IEL

Luminal Ag

Constitutive Migration

IL-10

Gut Homing

IL-10

Ag exposure in the gut induces tolerance

OVA BSA1.30 0.14

CD4

Foxp

3

Oral administration of ovalbumin induces Foxp3+ T cells from naïve precursors

OVA BSA

5d

MLN, Spleen, Colon LP

DO11.10 SCID

CD103 a marker of gut DC

DC

E-cadherinalphaE (CD103)beta7

Gated on CD11c high

Annacker et al., JEM 2005, Lindbom et al., 2005

•αE integrin subunit

•Expressed by mucosal DC and T Cells

•Pairs with β7, binds to E-cadherin on epithelial cells

Functional properties of CD103+ DC

CD103+ CD103-

Naïve T cellProliferation ++ ++

IFN-gamma - +

InflammatoryCytokines (IL-6, IL-23) - +

Imprint gut homingReceptors ++ -

CD103 expression in RAG-/- required for TR activityAnnacker et al., JEM 2005; Coombes et al., JEM 2007

Sorting DC for in vitro T cell differentiation assay

Balb/c

MLNCD11c MACS

CD103+ and CD103- subsets sorted on MoFlo

CD103

CD

11c

d4+ OVAp

analysis

d7

analysis

αCD3 d8

CD103+

CD103-

CFSE Naïve D011.10/SCID

CD4+ T

cytokines

IL-2

CD103+ DC promote the expression of Foxp3 by naïve T cells

CD103+ CD103-

CFSE

Foxp

3

1x10^5 0.5x10^5 0.25x10^50123456789

CD103+CD103-

p%

Fox

p3+

DC

T

CD103?

Proliferation

CytokinesHoming

Regulatory Regulatory Properties?Properties?

CD4

Foxp

3

Induction of Foxp3 by CD103+ DC is TGF-β dependent

- 0.1ng/ml 1ng/ml0

10

20

30

40

50CD103+CD103-

[TGF-β]

% F

oxp3

+

TGF-β-mediated induction of Foxp3 is increased in the presence of CD103+DC

0

10

20

30

40

50

Rel

ativ

e ex

pres

sion

/HPR

TCD103+ CD103-

aldh1a2

CD103+ DCs express higher levels of retinal dehydrogenase than CD103- DCs

Retinol (Vitamin A)

Retinoic Acid

Retinal

Cellular Retinoid Metabolism

ADHsSDR

ALDH1A1ALDH1A2ALDH1A3

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)

+ TGF-β + TGF-β/RA

CD103+

CD103-

beta

7

Foxp3

CD103+ CD103- CD103+

+RACD103-

+RA

0

20

40

60

% F

oxp3

+

p<0.001

p<0.001

ns

Retinoic acid acts as a co-factor for Foxp3 induction

Spontaneous induction of Foxp3 in the presence of CD103+ DC is inhibited by an RAR antagonistFoxp3+ 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 TR cells respond to inflammation and cure established colitis

•Compartmentalisation of the TR response-key role of IL-10 in control of tissue inflammation

•Gut is a site that favours induction of Foxp3+TR 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 TR cells responding to intestinal antigens

•In addition to natural TR cells, induced TR may play an important role in intestinal homeostasis

MLN

DC

T

CD103

?

Foxp3

IFNγCCR9

Colon

CD103

E-cadherin

DC TGF-βRA

CD103+ DC: mucosal DC that support the development of Foxp3+ TR cells with a mucosal seeking phenotype

Gut conditioningTGF-β, Vit A

DC

Tn

N N

TregTreg

Treg Treg

Foxp3+

MN

IL-23

IL-17IFN-γ

IL-6TNF-α

Th1Th1

Th1

TR activity

Ab blockadeTGF-β

IL-10

Dysregulatedresponses

Complimentary therapies for intestinal inflammation?

SWDSP:

Chris MottetHolm UhligOliver AnnackerAna IzcueJanine CoombesSophie HueSophia BuonocoreKarima SiddiquiKevin Maloy

Wellcome TrustMRCEU

Acknowledgements

NIHYasmine BelkaidJason Hall