Preferential Expression of Integrin αvβ8 Promotes Generation of Regulatory T Cells by Mouse CD103+ Dendritic Cells

doi:10.1053/j.gastro.2011.06.076

Gastroenterology

Volume 141, Issue 5, November 2011, Pages 1813-1820

https://doi.org/10.1053/j.gastro.2011.06.076 Get rights and content

Background & Aims

Immune responses in the intestine are controlled by regulatory T cells (Tregs), which prevent inflammation in response to commensal bacteria. A specific population of intestinal dendritic cells (DCs), marked by expression of CD103, generate Tregs more efficiently than other DC populations through mechanisms that involve retinoic acid and transforming growth factor (TGF)-β. However, it is not clear how CD103⁺ DCs are specialized for this function. We investigated the ability of CD103⁺ DCs to promote Treg generation through activation of TGF-β and the role of integrins with the αv subunit in this process.

Methods

Naïve T cells were cultured with purified DCs from mesenteric lymph nodes (MLNs) or intestines of wild-type and αv conditional knockout mice to assess generation of Tregs. Antigens were administered orally to mice, and antigen-specific generation of Tregs was measured in intestinal tissues. Expression of the integrin αv subunit was measured in purified subpopulations of DCs by quantitative polymerase chain reaction and immunoblot analyses.

Results

In vitro, CD103⁺ DCs generated more Tregs in the presence of latent TGF-β than other MLN DCs. Efficient generation of Tregs required expression of the integrin αv subunit by DCs; mice that lacked αv in immune cells did not convert naïve T cells to intestinal Tregs in response to oral antigen. CD103⁺ DCs derived from the MLNs selectively expressed high levels of integrin αvβ8 compared with other populations of DCs.

Conclusions

Expression of αvβ8 is required for CD103⁺ DCs to become specialized and activate latent TGF-β and generate Tregs during the induction of tolerance to intestinal antigens in mice.

Section snippets

Mice

αv-tie2 mice12, 13 backcrossed to BALB/c or C57BL/6 backgrounds (10 generations) were used. FoxP3 eGFP reporter mice were obtained from Vijay Kuchroo (Brigham and Women's Hospital, Boston, MA)⁸ and DO11.10 mice from the Jackson Laboratory (Bar Harbor, ME). All animals were housed under specific pathogen-free conditions at Massachusetts General Hospital. Animal experiments were performed under appropriate licenses within local and national guidelines for animal care.

In Vitro Treg Generation Assay

CD4⁺ T cells were sorted by

CD103⁺ MLN DCs Activate Latent TGF-β to Generate FoxP3⁺ Tregs

In agreement with previous studies,10, 11 we found that CD103⁺ DCs from mouse MLNs generated on average twice as many FoxP3⁺ T cells in in vitro coculture than their CD103⁻ counterparts (Figure 1A). This was dependent on TGF-β because TGF-β blocking antibodies completely prevented Treg generation by both CD103⁺ and CD103⁻ DCs (Figure 1A). Induction of FoxP3 was also significantly impaired when DCs and T cells were cultured in serum-free medium (Figure 1B and C), despite comparable T-cell

Discussion

A specific population of intestinal DCs, marked by expression of CD103, is emerging as important regulators of intestinal immunity through their ability to promote conversion of naïve T cells to FoxP3⁺ Tregs that home to the intestine. Here we present data showing that the increased ability of CD103⁺ DCs to generate Tregs both in vitro and in vivo is completely dependent on the expression of αv integrins. This is due to an increased ability of CD103⁺ DCs to activate latent TGF-β, and CD103⁺ DCs

Acknowledgments

The authors thank Joseph McCarty (MD Anderson Cancer Center, Houston, TX) for the kind gift of antibodies to β8 integrin, J. Rodrigo Mora and Scott Snapper (Massachusetts General Hospital) for helpful discussion as well as members of the Mora and Snapper laboratories for technical advice and reagents, and David Dombkowski (Massachusetts General Hospital) for FACS.

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: Conflicts of interest The authors disclose no conflicts.

: Funding Supported by grants from the Crohn's and Colitis Foundation of America and the Hood Pediatric Research Foundation (to A.L.-H.), the National Institutes of Health (grant RO1AI79198 to L.M.S.), the UK Medical Research Council (grant G0802069 to J.S.), a Wellcome Trust traveling fellowship (to S.M.), and the Philippe Foundation and the Bettencourt-Schueller Foundation (Young Scientist Award to H.P.).

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Original ResearchBasic and Translational—Alimentary TractPreferential Expression of Integrin αvβ8 Promotes Generation of Regulatory T Cells by Mouse CD103+ Dendritic Cells

Background & Aims

Methods

Results

Conclusions

Section snippets

Mice

In Vitro Treg Generation Assay

CD103+ MLN DCs Activate Latent TGF-β to Generate FoxP3+ Tregs

Discussion

Acknowledgments

Cell

Eur J Cell Biol

Immunity

Mucosal Immunol

Immunity

Learning tolerance while fighting ignorance

Cell

Unravelling the pathogenesis of inflammatory bowel disease

Nature

Control of immune pathology by regulatory T cells

Novartis Found Symp

Natural versus adaptive regulatory T cells

Nat Rev Immunol

Inducing and expanding regulatory T cell populations by foreign antigen

Nat Immunol

Sequential development of interleukin 2-dependent effector and regulatory T cells in response to endogenous systemic antigen

J Exp Med

Reciprocal developmental pathways for the generation of pathogenic effector TH17 and regulatory T cells

Nature

Conversion of peripheral CD4+CD25- naive T cells to CD4+CD25+ regulatory T cells by TGF-beta induction of transcription factor Foxp3

J Exp Med

Small intestine lamina propria dendritic cells promote de novo generation of Foxp3 T reg cells via retinoic acid

J Exp Med

Original Research
Basic and Translational—Alimentary Tract
Preferential Expression of Integrin αvβ8 Promotes Generation of Regulatory T Cells by Mouse CD103⁺ Dendritic Cells

CD103⁺ MLN DCs Activate Latent TGF-β to Generate FoxP3⁺ Tregs