Functional CD25<sup>–</sup> and CD25<sup>+</sup> mucosal regulatory T cells are induced in gut‐draining lymphoid tissue within 48 h after oral antigen application

103

Oral administration of Ag coupled to cholera toxin B subunit (CTB) efficiently induces peripheral immunological tolerance. We investigated the extent to which this oral tolerance is mediated by CD25+CD4+ regulatory T cells (Treg). We found that total Treg, KJ1–26+ Treg and CTLA-4+ Treg were all increased in Peyer’s patches, mesenteric lymph nodes, and, to a lesser extent, in spleen of mice after intragastric administration of OVA/CTB conjugate, which also increased TGF-β in serum. This could be abolished by coadministering cholera toxin or by treatment with anti-TGF-β mAb. CD25+ Treg, but also CD25−CD4+ T cells from OVA/CTB-treated BALB/c or DO11.10 mice efficiently suppressed effector T cell proliferation and IL-2 production in vitro. Following adoptive transfer, both T cell populations also suppressed OVA-specific T cell and delayed-type hypersensitivity responses in vivo. Foxp3 was strongly expressed by CD25+ Treg from OVA/CTB-treated mice, and treatment also markedly expanded CD25+Foxp3+ Treg. Furthermore, in Rag1−/− mice that had adoptively received highly purified Foxp3−CD25−CD4+ OT-II T cells OVA/CTB feeding efficiently induced CD25+ Treg cells, which expressed Foxp3 more strongly than naturally developing Treg and also had stronger ability to suppress effector OT-II T cell proliferation. A remaining CD25− T cell population, which also became suppressive in response to OVA/CTB treatment, did not express Foxp3. Our results demonstrate that oral tolerance induced by CTB-conjugated Ag is associated with increase in TGF-β and in both the frequency and suppressive capacity of Foxp3+ and CTLA-4+ CD25+ Treg together with the generation of both Foxp3+ and Foxp3−CD25− CD4+ Treg.

Section: Discussionsupporting

confidence: 93%

Oral Tolerance Induction with Antigen Conjugated to Cholera Toxin B Subunit Generates Both Foxp3+CD25+ and Foxp3−CD25− CD4+ Regulatory T Cells

Sun

Raghavan

Sjöling

et al. 2006

103

“…In models of orally fed Ag, both mesenteric LNs and Peyer's patches were shown to be the predominant sites of Ag presentation (58 -61), and critical for the induction of oral tolerance (59,62). To a lesser extent, oral Ag delivery has also been shown to induce clonal expansion of Ag-specific T cells in the spleen and, in cases in which high doses of Ag are administered, even in peripheral LNs (61,63,64). In our study, only very minute populations of donor transgenic T cells underwent proliferation in distal LNs.…”

Section: Discussionmentioning

confidence: 99%

Inhalation Tolerance Is Induced Selectively in Thoracic Lymph Nodes but Executed Pervasively at Distant Mucosal and Nonmucosal Tissues

Álvarez

Świrski

Yang

et al. 2006

Under immunogenic conditions, both the site of initial Ag exposure and consequent T cell priming in specific draining lymph nodes (LNs) imprint the ensuing immune response with lasting tissue-selective tropism. With respect to immune tolerance, whether the site of tolerance induction leads to compartmentalized or, alternatively, pervasive tolerance has not been formally investigated. Using a murine model of inhalation tolerance, we investigated whether the induction of respiratory mucosal tolerance precludes the development of de novo Th2 sensitization upon subsequent exposure to the same Ag at distant mucosal (gut) and nonmucosal (cutaneous) sites. By tracking the proliferation of CFSE-labeled OVA-TCR transgenic CD4+ T cells upon OVA inhalation in vivo, we defined the site of tolerance induction to be restricted to the thoracic LNs. Expectedly, inhalation tolerance prevented de novo Th2 sensitization upon subsequent exposure to the same Ag at the same site. Importantly, although gut- and skin-draining LNs were not used during tolerance induction, de novo Ag-specific proliferation and Th2 differentiation in these LNs, as well as memory/effector Th2 responses in the gut (allergic diarrhea) and skin (late-phase cutaneous responses) were inhibited upon immunogenic challenge to the same Ag. Interestingly, this pervasive tolerogenic phenotype was not associated with the presence of suppressive activity throughout the lymphatics; indeed, potent suppressive activity was detected solely in the spleen. These data indicate that while inhalation tolerance is selectively induced in local thoracic LNs, its tolerogenic activity resides systemically and leads to pervasive immune tolerance in distant mucosal and nonmucosal sites.

“…OVA-TCR transgenic T cells were isolated and labeled, as described previously (10,11). Briefly, at 8 -12 wk of age, DO11.10 transgenic mice were sacrificed, and LN and spleens were collected.…”

Section: Kinetics Of Ova-specific T Cell Response In Vitro and In Vivomentioning

confidence: 99%

“…Recently, we have shown that mucosal Tr are highly discriminative, suppressing inflammatory responses exclusively to the Ag used for tolerization and expanding their suppressive capacity by infectious tolerance (9). These mucosal Tr differentiate from naive CD4 ϩ T cells in the mucosa-draining lymphoid tissue within 72 h post-Ag application and reside in both CD25 ϩ as well as CD25 Ϫ subsets (10,11). The precise mechanisms underlying the induction of mucosal Tr and subsequent development of tolerance are the focus of extensive research that may yield important clues on the development of selective immunomodulatory therapies for T cellmediated inflammatory diseases, ranging from autoimmunity to transplant rejection and allergy.…”

mentioning

confidence: 99%

FcγRIIB Regulates Nasal and Oral Tolerance: A Role for Dendritic Cells

Samsom

Berkel

Helvoort

et al. 2005

Self Cite

Mucosal tolerance prevents the body from eliciting productive immune responses against harmless Ags that enter the body via the mucosae, and is mediated by the induction of regulatory T cells that differentiate in the mucosa-draining lymph nodes (LN) under defined conditions of Ag presentation. In this study, we show that mice deficient in FcγRIIB failed to develop mucosal tolerance to OVA, and demonstrate in vitro and in vivo a critical role for this receptor in modulating the Ag-presenting capacity of dendritic cells (DC). In vitro it was shown that absence of FcγRIIB under tolerogenic conditions led to increased IgG-induced release of inflammatory cytokines such as MCP-1, TNF-α, and IL-6 by bone marrow-derived DC, and increased their expression of costimulatory molecules, resulting in an altered immunogenic T cell response associated with increased IL-2 and IFN-γ secretion. In vivo we could show enhanced LN-DC activation and increased numbers of Ag-specific IFN-γ-producing T cells when FcγRIIB−/− mice were treated with OVA via the nasal mucosa, inferring that DC modulation by FcγRIIB directed the phenotype of the T cell response. Adoptive transfer of CD4+ T cells from the spleen of FcγRIIB−/− mice to naive acceptor mice demonstrated that OVA-responding T cells failed to differentiate into regulatory T cells, explaining the lack of tolerance in these mice. Our findings demonstrate that signaling via FcγRIIB on DC, initiated by local IgG in the mucosa-draining LN, down-regulates DC activation induced by nasally applied Ag, resulting in those defined conditions of Ag presentation that lead to Tr induction and tolerance.