Project description:Oral tolerance prevents pathological inflammatory responses towards innocuous foreign antigens via peripheral regulatory T cells (pTreg cells). However, whether a particular subset of antigen-presenting cells (APCs) is required during dietary antigen exposure to instruct naïve CD4+ T cells to differentiate into pTreg cells has not been defined. Using myeloid lineage-specific APC depletion in mice, we found that monocyte-derived APCs are dispensable, while classical dendritic cells (cDCs) are critical for pTreg cell induction and oral tolerance. CD11b¬â cDCs from the gut-draining lymph nodes efficiently induced pTreg cells, and conversely, loss of IRF8-dependent CD11bâ cDCs impaired their polarization, although oral tolerance remained intact. These data reveal the hierarchy of cDC subsets in pTreg cell induction and their redundancy during oral tolerance development. Four dendritic cell subpopulations from mouse mesenteric lymphnodes were sorted and compared in their gene expression profile
Project description:Oral tolerance prevents pathological inflammatory responses towards innocuous foreign antigens via peripheral regulatory T cells (pTreg cells). However, whether a particular subset of antigen-presenting cells (APCs) is required during dietary antigen exposure to instruct naïve CD4+ T cells to differentiate into pTreg cells has not been defined. Using myeloid lineage-specific APC depletion in mice, we found that monocyte-derived APCs are dispensable, while classical dendritic cells (cDCs) are critical for pTreg cell induction and oral tolerance. CD11b¬â?? cDCs from the gut-draining lymph nodes efficiently induced pTreg cells, and conversely, loss of IRF8-dependent CD11bâ?? cDCs impaired their polarization, although oral tolerance remained intact. These data reveal the hierarchy of cDC subsets in pTreg cell induction and their redundancy during oral tolerance development. Sorted naïve CD45.1 OT-II CD4 T cells were co-cultured with four dendritic cell subpopulations sorted from mouse mesenteric lymphnodes. 24h later OT-II cells were sorted again and compared in their gene expression profile.
Project description:Oral tolerance prevents pathological inflammatory responses towards innocuous foreign antigens via peripheral regulatory T cells (pTreg cells). However, whether a particular subset of antigen-presenting cells (APCs) is required during dietary antigen exposure to instruct naïve CD4+ T cells to differentiate into pTreg cells has not been defined. Using myeloid lineage-specific APC depletion in mice, we found that monocyte-derived APCs are dispensable, while classical dendritic cells (cDCs) are critical for pTreg cell induction and oral tolerance. CD11b¬– cDCs from the gut-draining lymph nodes efficiently induced pTreg cells, and conversely, loss of IRF8-dependent CD11b– cDCs impaired their polarization, although oral tolerance remained intact. These data reveal the hierarchy of cDC subsets in pTreg cell induction and their redundancy during oral tolerance development.
Project description:Oral tolerance prevents pathological inflammatory responses towards innocuous foreign antigens via peripheral regulatory T cells (pTreg cells). However, whether a particular subset of antigen-presenting cells (APCs) is required during dietary antigen exposure to instruct naïve CD4+ T cells to differentiate into pTreg cells has not been defined. Using myeloid lineage-specific APC depletion in mice, we found that monocyte-derived APCs are dispensable, while classical dendritic cells (cDCs) are critical for pTreg cell induction and oral tolerance. CD11b¬– cDCs from the gut-draining lymph nodes efficiently induced pTreg cells, and conversely, loss of IRF8-dependent CD11b– cDCs impaired their polarization, although oral tolerance remained intact. These data reveal the hierarchy of cDC subsets in pTreg cell induction and their redundancy during oral tolerance development.
Project description:T cells that encounter self-antigens after exiting the thymus avert autoimmunity through peripheral tolerance. Pathways for this include an unresponsive state known as anergy, clonal deletion, and T regulatory (Treg) cell induction. The transcription factor cues and kinetics that guide distinct peripheral tolerance outcomes remain unclear. Here, we found that anergic T cells are epigenetically primed for regulation by the non-classical AP-1 family member BATF. Tolerized BATF-deficient CD4+ T cells were resistant to anergy induction and instead underwent clonal deletion due to pro-apoptotic BIM (Bcl2l11) upregulation. During prolonged antigen exposure, BIM de-repression resulted in fewer PD-1+ conventional T cells as well as loss of peripherally-induced FOXP3+ Treg cells. Simultaneous Batf and Bcl2l11 knockdown meanwhile restored anergic T cell survival and Treg cell maintenance. The data identify the AP-1 nuclear factor BATF as a dominant driver of sustained T cell anergy and illustrate a mechanism for divergent peripheral tolerance fates.
Project description:T cells that encounter self-antigens after exiting the thymus avert autoimmunity through peripheral tolerance. Pathways for this include an unresponsive state known as anergy, clonal deletion, and T regulatory (Treg) cell induction. The transcription factor cues and kinetics that guide distinct peripheral tolerance outcomes remain unclear. Here, we found that anergic T cells are epigenetically primed for regulation by the non-classical AP-1 family member BATF. Tolerized BATF-deficient CD4+ T cells were resistant to anergy induction and instead underwent clonal deletion due to pro-apoptotic BIM (Bcl2l11) upregulation. During prolonged antigen exposure, BIM de-repression resulted in fewer PD-1+ conventional T cells as well as loss of peripherally-induced FOXP3+ Treg cells. Simultaneous Batf and Bcl2l11 knockdown meanwhile restored anergic T cell survival and Treg cell maintenance. The data identify the AP-1 nuclear factor BATF as a dominant driver of sustained T cell anergy and illustrate a mechanism for divergent peripheral tolerance fates.
Project description:Tolerance to self- or innocuous foreign antigens is vital for preservation of organismal health. Within the thymus, medullary thymic epithelial cells (mTECs) expressing AutoImmune Regulator, Aire, play a critical role in self-tolerance through deletion of autoreactive T cells and promotion of thymic regulatory T (Treg) cell development. A second wave of Treg cell differentiation occurs in the periphery, upon exposure to dietary and commensal microbiota derived antigens within the first few weeks of life, yet the cell types responsible for the generation of peripheral Treg (pTreg) cells are not known. Here we identified a new lineage of tolerogenic RORγt+ antigen-presenting cells (APC) with a hybrid dendritic cell (DC)-mTEC phenotype, dubbed Thetis cells (TCs), comprising 4 major sub-groups (TC I-IV), We uncovered a developmental wave of TCs within intestinal lymph nodes during a critical early life window, coincident with the wave of pTreg cell differentiation. While Aire+ TC I and III bore remarkable homology with Aire+ mTECs, including expression of tissue restricted self-antigens, TC IV lacked Aire expression and were enriched for molecules required for pTreg generation, including the TGF-β activating integrin αvβ8. Loss of either MHCII or Itgb8 expression by TCs led to a profound impairment in intestinal pTreg differentiation, with onset of intestinal inflammation. In contrast, MHCII expression by RORγt+ group 3 innate lymphoid cells (ILC3) and classical DCs was neither sufficient nor required for pTreg generation, further implicating TCs as the critical tolerogenic RORγt+ APC. Our studies reveal parallel pathways for establishment of tolerance to self and foreign antigen within the thymus and periphery, marked by involvement of shared cellular and transcriptional programs.
Project description:Tolerance to self- or innocuous foreign antigens is vital for preservation of organismal health. Within the thymus, medullary thymic epithelial cells (mTECs) expressing AutoImmune Regulator, Aire, play a critical role in self-tolerance through deletion of autoreactive T cells and promotion of thymic regulatory T (Treg) cell development. A second wave of Treg cell differentiation occurs in the periphery, upon exposure to dietary and commensal microbiota derived antigens within the first few weeks of life, yet the cell types responsible for the generation of peripheral Treg (pTreg) cells are not known. Here we identified a new lineage of tolerogenic RORγt+ antigen-presenting cells (APC) with a hybrid dendritic cell (DC)-mTEC phenotype, dubbed Thetis cells (TCs), comprising 4 major sub-groups (TC I-IV), We uncovered a developmental wave of TCs within intestinal lymph nodes during a critical early life window, coincident with the wave of pTreg cell differentiation. While Aire+ TC I and III bore remarkable homology with Aire+ mTECs, including expression of tissue restricted self-antigens, TC IV lacked Aire expression and were enriched for molecules required for pTreg generation, including the TGF-β activating integrin αvβ8. Loss of either MHCII or Itgb8 expression by TCs led to a profound impairment in intestinal pTreg differentiation, with onset of intestinal inflammation. In contrast, MHCII expression by RORγt+ group 3 innate lymphoid cells (ILC3) and classical DCs was neither sufficient nor required for pTreg generation, further implicating TCs as the critical tolerogenic RORγt+ APC. Our studies reveal parallel pathways for establishment of tolerance to self and foreign antigen within the thymus and periphery, marked by involvement of shared cellular and transcriptional programs.