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Gut-Tropic T Cells That Express Integrin α4β7 and CCR9 Are Required for Induction of Oral Immune Tolerance in Mice

2011; Elsevier BV; Volume: 141; Issue: 6 Linguagem: Inglês

10.1053/j.gastro.2011.09.015

1528-0012

Barbara Cassani, Eduardo J. Villablanca, Francisco J. Quintana, Paul E. Love, Adam Lacy‐Hulbert, William S. Blaner, Tim Sparwasser, Scott B. Snapper, Howard L. Weiner, J. Rodrigo Mora,

Immune Response and Inflammation

Background & AimsInduction of oral immune tolerance (OT) blocks proinflammatory responses to orally administered antigens and might be used to treat autoimmune conditions. We investigated whether gut-tropic T cells that express the integrin α4β7 and the chemokine receptor CCR9 are required for OT.MethodsSkin delayed-type hypersensitivity and experimental autoimmune encephalomyelitis were used to monitor OT in mice. To assess the role of receptors that mediate localization of lymphocytes to the gut (gut-homing receptors) in induction of OT, we studied CCR9−/− and β7−/− mice and also blocked the α4β7 ligand MAdCAM-1 in wild-type mice. We used DEREG and Scurfy mice to assess the role of Foxp3+ regulatory T cells (Treg) and IL-10−/− and IL-10Rβ−/− mice to examine the role of interleukin (IL)-10 in induction of OT.ResultsOT could not be induced in CCR9−/− or β7−/− mice, or when MAdCAM-1 was blocked in wild-type mice, indicating that gut-homing receptors are required for oral tolerization. Consistent with the role of all-trans retinoic acid in inducing gut-homing T cells, OT could not be induced in mice depleted of vitamin A. OT was rescued in CCR9−/− mice following adoptive transfer of wild-type T cells, but not CCR9−/− or β7−/− T cells. Gut-homing T cells are therefore necessary and sufficient to induce OT. Wild-type Treg and IL-10 were required to restore OT to CCR9−/− mice, indicating that homing and functional differentiation of IL-10–producing Treg in the gut is required for OT. Conversely, transfer of CCR9−/− or β7−/− T cells to wild-type mice partially inhibited OT.ConclusionsExpression of CCR9 and α4β7 on T cells and their subsequent localization to the gut is required for induction of OT in mice. Therapies designed to block gut-homing receptors might, under some conditions, interfere with normal tolerogenic mechanisms in the intestinal mucosa. Induction of oral immune tolerance (OT) blocks proinflammatory responses to orally administered antigens and might be used to treat autoimmune conditions. We investigated whether gut-tropic T cells that express the integrin α4β7 and the chemokine receptor CCR9 are required for OT. Skin delayed-type hypersensitivity and experimental autoimmune encephalomyelitis were used to monitor OT in mice. To assess the role of receptors that mediate localization of lymphocytes to the gut (gut-homing receptors) in induction of OT, we studied CCR9−/− and β7−/− mice and also blocked the α4β7 ligand MAdCAM-1 in wild-type mice. We used DEREG and Scurfy mice to assess the role of Foxp3+ regulatory T cells (Treg) and IL-10−/− and IL-10Rβ−/− mice to examine the role of interleukin (IL)-10 in induction of OT. OT could not be induced in CCR9−/− or β7−/− mice, or when MAdCAM-1 was blocked in wild-type mice, indicating that gut-homing receptors are required for oral tolerization. Consistent with the role of all-trans retinoic acid in inducing gut-homing T cells, OT could not be induced in mice depleted of vitamin A. OT was rescued in CCR9−/− mice following adoptive transfer of wild-type T cells, but not CCR9−/− or β7−/− T cells. Gut-homing T cells are therefore necessary and sufficient to induce OT. Wild-type Treg and IL-10 were required to restore OT to CCR9−/− mice, indicating that homing and functional differentiation of IL-10–producing Treg in the gut is required for OT. Conversely, transfer of CCR9−/− or β7−/− T cells to wild-type mice partially inhibited OT. Expression of CCR9 and α4β7 on T cells and their subsequent localization to the gut is required for induction of OT in mice. Therapies designed to block gut-homing receptors might, under some conditions, interfere with normal tolerogenic mechanisms in the intestinal mucosa.