Development Of Foxp3 Research Articles

Treg donation of sIL-6R to promote intestinal integrity and repair

Abstract IBD affects roughly 1.6 million US adults, with its prevalence increasing since the late 1990s. Characterized by unchecked intestinal inflammation, multiple proinflammatory cytokines including IL6 have been implicated as critical factors in this pathology. It has been established that EZH2 is a gene involved in the production of specific histone methyltransferase enzymes, as well as in the differentiation of Treg cells. The association between the Treg master transcription factor, Foxp3 and EZH2 results in the suppressive function of Tregs, with our previous work revealing impairment of this interaction under the influence of IL6 signaling in an inflamed intestinal setting. We investigated this further in a murine preventative T cell transfer model of colitis that involved injecting donor Treg cells that lacked IL6Ra, into immunocompromised mice. Histological scoring of the mice receiving the IL6Rko Tregs revealed a resolved inflammatory milieu and flow cytometric analysis of cells isolated from the spleens and MLNs showed increased Foxp3+ expression when compared to mice that received WT Tregs. Foxp3IL6Rako mice were subjected to a DSS model of colitis to further characterize the absence of the IL6R on Treg function in the intestinal milieu. Exacerbated signs of colitis were observed through histology and colon shortening of the conditional knockout mice when compared to their WT counterparts. We postulate that Tregs could be acting as a donor of sILR to promote intestinal integrity and healing. Further experiments will be conducted to define a role for the IL6R in the development of Foxp3+ cells, along with outlining the instrumental process of sIL6R donation in the intestinal milieu. Supported by Mayo Clinic Graduate School for Biomedical Sciences

The emerging role of transcription factor FOXP3 in thyroid cancer.

Transcription factor FOXP3 is a crucial regulator in the development and function of regulatory T cells (Treg) that are essential for immunological tolerance and homeostasis. Numerous studies have indicated the correlation of tumor infiltrating FOXP3+ Treg upregulation with poor prognostic parameters in thyroid cancer, including lymph node metastases, extrathyroidal extension, and multifocality. Most immune-checkpoint molecules are expressed in Treg. The blockage of such signals with checkpoint inhibitors has been approved for several solid tumors, but not yet for thyroid cancer. Thyroid abnormalities may be induced by checkpoint inhibitors. For example, hypothyroidism, thyrotoxicosis, painless thyroiditis, or even thyroid storm are more frequently associated with anti-PD-1 antibodies (pembrolizumab and nivolumab). Therefore, Targeting FOXP3+ Treg may have impacts on checkpoint molecules and the growth of thyroid cancer. Several factors may impact the role and stability of FOXP3, such as alternative RNA splicing, mutations, and post-translational modification. In addition, the role of FOXP3+ Treg in the tumor microenvironment is also affected by the complex regulatory network formed by FOXP3 and its transcriptional partners. Here we discussed how the expression and function of FOXP3 were regulated and how FOXP3 interacted with its targets in Treg, aiming to help the development of FOXP3 as a potential therapeutic target for thyroid cancer.

Oral Immunotherapy with Egg Peptides Induces Innate and Adaptive Tolerogenic Responses.

The mechanism through which peptide-based immunotherapy provides effective desensitization toward food allergy is investigated. Ex vivo experiments are conducted with intestinal epithelial cells (IECs), dendritic cells (DCs), and T cells from mice sensitized to egg white (EW) and either left untreated or tolerized by the oral administration of a hydrolysate of ovalbumin with pepsin (OP). IECs from EW-sensitized mice upregulate Il33 and Tslp to a higher extent than those from tolerized mice and induce bone marrow (BM)-DCs to express Tnfsf4 and produce pro-inflammatory cytokines. On the other hand, incubation with OP upregulates Aldh1a1 in IEC cultures and BM-DCs conditioned with supernatants of OP-pulsed IECs also overexpress Aldh1a2 and Tgfb1. DCs from tolerized mice, in co-culture with CD4+ T cells from sensitized mice, reduce the secretion of IL-5, IFN-γ, and IL-17, following stimulation with EW, to a level similar than DCs from sham-sensitized mice. Furthermore, incubation with OP of DCs and CD4+ T cells, regardless of the mouse sentitization status, promotes the secretion of TGF-β and the generation of Foxp3+ RORγt+ cells. OP induces the expression of aldehyde dehydrogenase enzymes in cells of the innate immune system and the development of Foxp3+ RORγt+ T cells.

OBESITY, INFLAMMATION, AND T-CELL METABOLISM

Aim: The overview of the interdependence of the immune system and the system metabolism. Regulation of metabolism is immunomodulatory, and targeting key cellular metabolic enzymes impacts T-cell development, altering the immune functions. Background: The diet, gastrointestinal microbiota and the balanced function of liver, adipose and muscle tissues underlie the immune ecology. Chronic inflammation (macrophage, TH1, and TH17 T-cell infiltration) associates with obesity, and the development of metabolic syndrome, cardiovascular diseases, type 2 diabetes, IBD and intestinal malignancies. While naive T-cells use beta-oxidation, TCA cycle, and mitochondrial respiration to produce ATP, activated T-cells, similarly to cancer cells, employ the Warburg’s effect to power their function. The development of T-cells depends on key metabolic regulators, like mTORC1 (TH1 and TH17 T-cells) and mTORC2 (TH2 T-cells). Inhibition of HIF1-alpha (critical for TH17 T-cells) results in the development of FOXP3+ Treg T-cells, improving autoimmune disorders. Metabolic flexibility of normal cells underlines the successful treatment of neoplastic, autoimmune and hyper-sensitivity disorders. Conclusions: The immune system influences the system metabolism, and depends on the function of adipose tissue, muscles, liver, pancreas, lungs and gastro-intestinal tract. Diet and pharmacological regulation of T-cell metabolic activity influence immune function during autoimmunity, infections, and vaccinations.

Introduction of Human Flt3-L and GM-CSF into Humanized Mice Enhances the Reconstitution and Maturation of Myeloid Dendritic Cells and the Development of Foxp3+CD4+ T Cells.

Two cytokines, fms-related tyrosine kinase 3 ligand (Flt3-L) and granulocyte-macrophage colony-stimulating factor (GM-CSF) are considered to be the essential regulators of dendritic cell (DC) development in vivo. However, the combined effect of Flt3-L and GM-CSF on human DCs has not been evaluated in vivo. In this study, we, therefore, aimed at evaluating this using a humanized mouse model. Humanized non-obese diabetic/SCID/Jak3null (hNOJ) mice were constructed by transplanting hematopoietic stem cells from human umbilical cord blood into newborn NOJ mice, and in vivo transfection (IVT) was performed by hydrodynamic injection-mediated gene delivery using plasmids encoding human Flt3-L and GM-CSF. Following IVT, Flt3-L and GM-CSF were successfully induced in hNOJ mice. At 10 days post-IVT, we found, in the spleen, that treatment with both Flt3-L and GM-CSF enhanced the reconstitution of two myeloid DC subsets, CD14−CD1c+ conventional DCs (cDCs) and CD14−CD141+ cDCs, in addition to CD14+ monocyte-like cells expressing CD1c and/or CD141. GM-CSF alone had less effect on the reconstitution of these myeloid cell populations. By contrast, none of the cytokine treatments enhanced CD123+ plasmacytoid DC (pDC) reconstitution. Regardless of the reconstitution levels, three cell populations (CD1c+ myeloid cells, CD141+ myeloid cells, and pDCs) could be matured by treatment with cytokines, in terms of upregulation of CD40, CD80, CD86, and CD184/CXCR4 and downregulation of CD195/CCR5. In particular, GM-CSF contributed to upregulation of CD80 in all these cell populations. Interestingly, we further observed that Foxp3+ cells within splenic CD4+ T cells were significantly increased in the presence of GM-CSF. Foxp3+ T cells could be subdivided into two subpopulations, CD45RA−Foxp3hi and CD45RA−Foxp3lo T cells. Whereas CD45RA−Foxp3hi T cells were increased only after treatment with GM-CSF alone, CD45RA−Foxp3lo T cells were increased only after treatment with both Flt3-L and GM-CSF. Treatment with Flt3-L alone had no effect on the number of Foxp3+ T cells. The correlation analysis demonstrated that the development of these Foxp3+ subpopulations was associated with the maturation status of DC(-like) cells. Taken together, this study provides a platform for studying the in vivo effect of Flt3-L and GM-CSF on human DCs and regulatory T cells.

Prdm1 Regulates Thymic Epithelial Function To Prevent Autoimmunity.

Autoimmunity is largely prevented by medullary thymic epithelial cells (TECs) through their expression and presentation of tissue-specific Ags to developing thymocytes, resulting in deletion of self-reactive T cells and supporting regulatory T cell development. The transcription factor Prdm1 has been implicated in autoimmune diseases in humans through genome-wide association studies and in mice using cell type–specific deletion of Prdm1 in T and dendritic cells. In this article, we demonstrate that Prdm1 functions in TECs to prevent autoimmunity in mice. Prdm1 is expressed by a subset of mouse TECs, and conditional deletion of Prdm1 in either Keratin 14– or Foxn1-expressing cells in mice resulted in multisymptom autoimmune pathology. Notably, the development of Foxp3+ regulatory T cells occurs normally in the absence of Blimp1. Importantly, nude mice developed anti-nuclear Abs when transplanted with Prdm1 null TECs, but not wild-type TECs, indicating that Prdm1 functions in TECs to regulate autoantibody production. We show that Prdm1 acts independently of Aire, a crucial transcription factor implicated in medullary TEC function. Collectively, our data highlight a previously unrecognized role for Prdm1 in regulating thymic epithelial function.

Novel role of Parkinson’s protein DJ-1/Park7 in the development of Foxp3+ regulatory T cells

Parkinson’s protein DJ-1/Park7, is a key regulator of redox signalling in neurons and muscles by regulating reactive oxygen species (ROS) production. Defects in DJ-1 are suggested to cause autosomal recessive early-onset Parkinson's disease. Further, deregulated DJ-1 signalling has been ascribed to other pathologies including diabetes (type II) and in obesity. How DJ-1/Park7 is involved in the maintenance of immune T cells especially suppressor regulatory T cells (Tregs) is not well defined. We explored this important question by using DJ-1 knock-out mice at cellular and molecular level. We found that DJ-1 is involved, both in vivo and in vitro, in the development of natural and induced Tregs. Differentiation of induced Tregs is regulated by mammalian target of rapamycin (mTOR)/Serum and glucocorticoid kinase 1 (Sgk1) and ROS/NF ƙ B pathway. Thus, our data highlights the importance of DJ-1 in the development of Tregs.

Aire Enforces Immune Tolerance by Directing Autoreactive T Cells into the Regulatory T Cell Lineage

The promiscuous expression of tissue-restricted antigens in the thymus, driven in part by autoimmune regulator (Aire), is critical for the protection of peripheral tissues from autoimmune attack. Aire-dependent processes are thought to promote both clonal deletion and the development of Foxp3(+) regulatory T (Treg) cells, suggesting that autoimmunity associated with Aire deficiency results from two failed tolerance mechanisms. Here, examination of autoimmune lesions in Aire(-/-) mice revealed an unexpected third possibility. We found that the predominant conventional Tcell clonotypes infiltrating target lesions express antigen receptors that were preferentially expressed by Foxp3(+) Treg cells in Aire(+/+) mice. Thus, Aire enforces immune tolerance by ensuring that distinct autoreactive Tcell specificities differentiate into the Treg cell lineage; dysregulation of this process results in the diversion of Treg cell-biased clonotypes into pathogenic conventional Tcells.

4-1BB ligand signaling to T cells limits T cell activation.

4-1BB ligand (4-1BBL) and its receptor, 4-1BB, are both induced on T cells after activation, but little is known about the role of 4-1BBL. In this study we show that 4-1BBL can transmit signals that limit T cell effector activity under tolerogenic conditions. Cross-linking 4-1BBL inhibited IL-2 production in vitro, primarily with suboptimal TCR stimulation. Furthermore, naive 4-1BBL-deficient OT-II transgenic T cells displayed a greater conversion to effector T cells in vivo when responding to soluble OVA peptide in wild-type hosts, whereas development of Foxp3(+) regulatory T cells was not altered. A greater number of effector T cells also differentiated from naive wild-type OT-II T cells when transferred into 4-1BB-deficient hosts, suggesting that APC-derived 4-1BB is likely to trigger 4-1BBL. Indeed, effector T cells that could not express 4-1BBL accumulated in larger numbers in vitro when stimulated with 4-1BB-expressing mesenteric lymph node dendritic cells. 4-1BBL was expressed on T cells when Ag presentation was limiting, and 4-1BBL was aberrantly expressed at very high levels on T cells that could not express 4-1BB. Trans-ligation, Ab capture, and endocytosis experiments additionally showed that T cell-intrinsic 4-1BB regulated internalization of membrane 4-1BBL, implying that the strong induction of 4-1BB on T cells may counteract the suppressive function of 4-1BBL by limiting its availability. These data suggest that 4-1BBL expressed on T cells can restrain effector T cell development, creating a more favorable regulatory T cell to effector cell balance under tolerogenic conditions, and this may be particularly active in mucosal barrier tissues where 4-1BB-expressing regulatory dendritic cells present Ag.

Interleukin-2 drives immature double negative thymocytes into γδ T cells expressing Foxp3 on a stromal cell line in vitro

γδ T cells are exported from the thymus as innate-like lymphocytes that can immediately respond to antigens. In the thymus, γδ T cells diverge into functionally distinct lineages. It is not known whether γδ T cells differentiate into regulatory cells that express Foxp3, which is an essential transcription factor for CD4+ regulatory T cells. In this study, we analyzed CD25+ immature thymocytes that give rise to both αβ and γδ thymocytes. These precursor cells have the potential to differentiate into Foxp3+ γδ T cells on a stromal cell line, TSt4-Dll1. Development of Foxp3+ γδ thymocytes in this culture was dependent on IL-2. IL-2 stimulation induced Id3, Egr1, and Egr3 expression in CD25+ immature thymocytes, suggesting that it could activate signaling molecules that are downstream of TCR signaling. The induction of Foxp3 in precursor γδ T cells suggested that IL-2 could activate the Foxp3 gene early in thymocyte development.

Vitamin D in pediatric rheumatology

One century after its discovery vitamin D is shown to be, in fact, a pleiotropic steroid hormone which, beside regulation of calcium homeostasis and bone turnover, has anti-proliferative, pro-differentiation, anti-bacterial, immunomodulatory and anti-inflammatory properties in various cells and tissues. The D hormone [1α,25(OH)2D], regulated in endocrine, autocrine and paracrine manner, must be bound to the specific nuclear vitamin D receptor (VDR) to exert epigenetic and genetic effects influencing more than 2000 genes in all tissues and immune cells, essential for proliferation, differentiation and immunoregulation. VDR agonists inhibit in myeloid DCs, but not in plazmacytoid DCs, expression of surface co-stimulatory molecules such as MHC class II, CD40, CD80 and CD86. In T cells, 1,25(OH)2D decreases the production of IL-2, IL-17 and interferon-γ (IFNγ) and attenuates the cytotoxic activity and proliferation of CD4+ and CD8+ T cells, and promote the development of FoxP3+ regulatory T (TReg) cells and IL-10-producing T regulatory type 1 cells. In contrast to glucocorticoids which are non-selective immunosuppressive compaunds, 1α,25(OH)2D induces monocyte proliferation and the expression of interleukin-1 (IL-1) and cathelicidin (an antimicrobial peptide) by macrophages, thereby contributing to innate immune responses to some bacteria. Additionally it was shown that 1α,25(OH)2D can override steroid resistance and antagonize its negative bone turnover influence. The discovery of the immunomodulatory and anti-tumor properties of D-hormone prompted researchers to investigate possibility of its use as a preventive and therapeutic agent for different autoimmune and malignant diseases. Several publications in last years have found a high prevalence of vitamin D deficiency in JIA, SLE and other chronic inflammatory diseases in childhood, with the mean values of 25(OH)D levels at the lower end of ‘acceptable’ range. Measurement of 25(OH)D level (as the only standardized toll to estimate vitamin D status) is actually only the reflection of the balance between food and/or supplement vitamin D diet intake and its utilization in the local tissues into the active D hormone (especially immune cells in the state of chronic inflammation). Recent recommendations and clinical guidelines have suggested vitamin D supplementation of up to 2000 IU/d to be safe and well tolerated in children with chronic diseases. New recommendations and guidelines for vitamin D supplementation, as adjunct treatment option in JIA and other chronic inflammatory rheumatic diseases, is an appealing need due to its pleiotropic effects. It can both minimize bone fragility and contribute improvement of impaired immunity regulation in rheumatic diseases in children, especially those with necessity for long term steroid treatment.

Development of Foxp3+ regulatory T cell: epigenetics and more…

not submitted for publication Published: 23 November 2011 doi:10.1186/1479-5876-9-S2-I4 Cite this article as: Huhn: Development of Foxp3+ regulatory T cell: epigenetics and more.... Journal of Translational Medicine 2011 9(Suppl 2):I4. Submit your next manuscript to BioMed Central and take full advantage of: • Convenient online submission • Thorough peer review • No space constraints or color figure charges • Immediate publication on acceptance • Inclusion in PubMed, CAS, Scopus and Google Scholar • Research which is freely available for redistribution Submit your manuscript at www.biomedcentral.com/submit Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany Huhn Journal of Translational Medicine 2011, 9(Suppl 2):I4 http://www.translational-medicine.com/content/9/S2/I4 © 2011 Huhn; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

TRAF6 directs commitment to regulatory T cells in thymocytes

Regulatory T cells (Tregs), a subset of CD4(+) helper T cells, are crucial for immunological self-tolerance. Defect in development or function of Tregs results in autoimmune disease in human and mice. Whereas it is known that Tregs mainly develop in the thymus, the molecular mechanism underlying development of Treg is not fully understood. TRAF6-deficient mice showed a severe defect in the Treg development in thymus. In vitro fetal thymic organ culture experiments indicated that the defect is ascribed to the absence of TRAF6 in thymic cells. Moreover, mixed fetal liver transfer experiments revealed that the development of Foxp3(+) cells differentiated from Traf6(-/-) hematopoietic cells was specifically impaired in the thymus, indicating cell-intrinsic requirement for TRAF6 in the Treg development. On the other hand, TRAF6 is not required for the development of conventional CD4(+) T cell. In addition, TGFβ-dependent induction of Foxp3 in CD4(+) T cells in vitro was not impaired by the absence of TRAF6. Overall, our data indicate that TRAF6 plays an essential role on the commitment of immature thymocytes to thymic Tregs in cell-intrinsic fashion.

Discontinuation of calcineurin inhibitors treatment allows the development of FOXP3+ regulatory T-cells in patients after kidney transplantation

This study investigated specific gene expression profiles in patients with donor-specific cytotoxic-hyporesponsiveness, reflected by cytotoxic T-lymphocyte precursor frequency (CTLpf). The effect of calcineurin inhibitor (CNI) withdrawal was studied on markers for cytotoxicity (perforin, granzyme B), apoptosis (Fas,FasL), Th1 and Th2 cytokines (IL-2, IL-10), Th1 and Th2 transcription factors (T-bet, GATA 3), Th17 transcription factor and cytokine (RORγt, IL-17), and for immune regulation/activation (CD25, FOXP3). Peripheral blood samples from renal allograft recipients (n = 18) more than two yr after transplantation with stable renal function were analyzed before and four months after CNI withdrawal. Additionally, systolic and diastolic blood pressure, cholesterol, serum creatinine and proteinuria were evaluated, and no significant differences were measured before and after CNI withdrawal. However, CNIs' discontinuation influenced peripheral gene expression profiles. After CNI withdrawal, the mRNA expression of Granzyme B, Perforin, Fas, FasL, T-bet, GATA3 and CD25 were significantly lower than during CNI treatment. After CNI discontinuation, donor-specific CTLpf decreased, while FOXP3 expression discriminated between detectable and non-detectable donor-specific cytolysis reactivity; FOXP3 transcript values were highest in absence of donor-specific cytotoxicity (p < 0.01). Our study shows CNI withdrawal in stable kidney transplant recipients two yr after transplantation is safe. Moreover, discontinuation of CNIs' treatment allows FOXP3+ regulatory T-cells development, resulting in a significant decrease of anti-donor immune reactivity.

Smad2 Positively Regulates the Generation of Th17 Cells*[S

Development of Foxp3(+) regulatory T cells and pro-inflammatory Th17 cells from naive CD4(+) T cells requires transforming growth factor-β (TGF-β) signaling. Although Smad4 and Smad3 have been previously shown to regulate Treg cell induction by TGF-β, they are not required in the development of Th17 cells. Thus, how TGF-β regulates Th17 cell differentiation remains unclear. In this study, we found that TGF-β-induced Foxp3 expression was significantly reduced in the absence of Smad2. More importantly, Smad2 deficiency led to reduced Th17 differentiation in vitro and in vivo. In the experimental autoimmune encephalomyelitis model, Smad2 deficiency in T cells significantly ameliorated disease severity and reduced generation of Th17 cells. Furthermore, we found that Smad2 associated with retinoid acid receptor-related orphan receptor-γt (RORγt) and enhanced RORγt-induced Th17 cell generation. These results demonstrate that Smad2 positively regulates the generation of inflammatory Th17 cells.

Cbl-b and Itch: Key Regulators of Peripheral T-cell Tolerance

E3 ligases Cbl-b and Itch have emerged as dominant "tolerogenic" regulators of T cells because their deficiency results in severe autoimmune diseases. Cbl-b and Itch ligase activity regulate T-cell anergy and development of Foxp3+ regulatory T cells (Treg) in the periphery by modulating key components of T-cell receptor (TCR) and transforming growth factor-beta (TGF-beta) signaling. Manipulation of Cbl-b and Itch activities may provide unique opportunities to develop future therapies for immune disorders such as autoimmunity and cancer.

Development of Foxp3+ Regulatory T Cells Is Driven by the c-Rel Enhanceosome

Regulatory T (Treg) cells are essential for maintaining immune homeostasis. Although Foxp3 expression marks the commitment of progenitors to Treg cell lineage, how Treg cells are generated during lymphocyte development remains enigmatic. We report here that the c-Rel transcription factor controlled development of Treg cells by promoting the formation of a Foxp3-specific enhanceosome. This enhanceosome contained c-Rel, p65, NFAT, Smad, and CREB. Although Smad and CREB first bound to Foxp3 enhancers, they later moved to the promoter to form the c-Rel enhanceosome. c-Rel-deficient mice had up to 90% reductions of Treg cells compared to wild-type mice, and c-Rel-deficient T cells were compromised in Treg cell differentiation. Thus, Treg cell development is controlled by a c-Rel enhanceosome, and strategies targeting Rel-NF-kappaB can be effective for manipulating Treg cell function.

Induction of Foxp3 demethylation increases regulatory CD4+CD25+ T cells and prevents the occurrence of diabetes in mice

CD4(+)CD25(+) regulatory T cells (Treg), a subpopulation of CD4(+) T cells, regulate immune responses. Foxp3 is a key transcription factor for the development and function of Treg cells. During T-cell activation in vitro, a DNA demethylation agent 5-Aza-2'-deoxycytydine (DAC) can induce Foxp3 expression in CD4(+)CD25(-) Foxp3(-) cells via altering methylation status of a conserved element in the 5'-untranslated region of the Foxp3 gene. However, the effects of this agent on the development of Foxp3(+) Treg cells in the thymus and in vivo are poorly understood. In the present study, a short-term treatment with a low dose of DAC significantly increased the ratios of thymic CD4(+)CD8(-) CD25(+) cells or CD4(+)CD8(-) Foxp3(+) cells to CD4(+)CD8(-) cells, and the total numbers of thymic CD4(+)CD8(-)Foxp3(+) Treg cells or CD4(+)CD8(-)CD25(+)Foxp3(+) Treg cells in the thymus in mice. DAC-treatment induced the Foxp3 expression and the significant demethylation of a CpG island in the first intron of the Foxp3 gene in CD4(+)CD8(-)CD25(+) cells predominantly. Furthermore, CD4(+)CD8(-)CD25(+) thymocytes in DAC-treated mice exhibited enhanced immunosuppressive function than those in control mice. In addition, DAC treatment in vivo was effective in improving the clinical course of diabetes in cyclophosphamide (CY)-potentiated non-obese diabetic mice (CY-NOD). Thus, the in vivo treatment with DAC can significantly promote the development of natural thymic CD4(+)CD25(+)Foxp3(+) Treg cells through Foxp3 demethylation, implicating a therapeutic application of DAC in patients suffering from autoimmune diseases.

Mucosally induced Immunological Tolerance, Regulatory T Cells and the Adjuvant Effect by Cholera Toxin B Subunit

Induction of peripheral immunological tolerance by mucosal administration of selected antigens (Ags) ('oral tolerance') is an attractive, yet medically little developed, approach to prevent or treat selected autoimmune or allergic disorders. A highly effective way to maximize oral tolerance induction for immunotherapeutic purposes is to administer the relevant Ag together with, and preferably linked to the non-toxic B subunit protein of cholera toxin (CTB). Oral, nasal or sublingual administration of such Ag/CTB conjugates or gene fusion proteins have been found to induce tolerance with superior efficiency compared with administration of Ag alone, including the suppression of various autoimmune disorders and allergies in animal models. In a proof-of-concept clinical trial in patients with Behcet's disease, this was extended with highly promising results to prevent relapse of autoimmune uveitis. Tolerization by mucosal Ag/CTB administration results in a strong increase in Ag-specific regulatory CD4(+) T cells, apparently via two separate pathways: one using B cells as APCs and leading to a strong expansion of Foxp3(+) Treg cells which can both suppress and mediate apoptotic depletion of effector T cells, and one being B cell-independent and associated with development of Foxp3(-) regulatory T cells that express membrane latency-associated peptide and transforming growth factor (TGF-beta) and/or IL-10. The ability of CTB to dramatically increase mucosal Ag uptake and presentation by different APCs through binding to GM1 ganglioside (which makes most B cells effective APCs irrespective of their Ag specificity), together with CTB-mediated stimulation of TGF-beta and IL-10 production and inhibition of IL-6 formation may explain the dramatic potentiation of oral tolerance by mucosal Ags presented with CTB.

663 A Secreted Polysaccharide from Bifidobacterium Infantis 35624 Promotes Development of FOXP3+ T Regulatory Cells in Gnotobiotic Mice In Vivo.

663 A Secreted Polysaccharide from Bifidobacterium Infantis 35624 Promotes Development of FOXP3+ T Regulatory Cells in Gnotobiotic Mice In Vivo.