Project description:Dendritic cells (DC) play critical roles in central and peripheral T cell tolerance. DC found in the steady-state periphery undergo an homeostatic, tolerogenic, maturation that promotes interaction with naive T cells and induction of abortive responses. In contrast, thymic DC are thought to exist solely in an immature state. In this study, we show that XCR1+ thymic DC constitutively mature into a stage characterized by high levels of molecules involved in T cell activation. This unanticipated mature stage corresponded to a third of the XCR1+ thymic DC and fully accounted for their ability to cross-present self-antigens to developing T cells. Transcriptomic analysis of the XCR1+ DC found in thymus and steady-state periphery revealed that their maturation involves profound and convergent changes. Unexpectedly, maturation resulted in down-regulation of genes conferring their specific function on XCR1+ DC. Paradoxically, upon maturation, central and peripheral tolerogenic XCR1+ DC up-regulated many genes thought to drive pro-inflammatory T-cell responses. Thus, our results reveal that thymic XCR1+ DC undergo constitutive maturation and emphasize the common mechanisms operating for both central and peripheral tolerance induction by XCR1+ DC. DC were isolated from lymphoid organs as previously described (Vremec et al., 2000). DC subsets were sorted by flow cytometry according to the marker combinations described in the âcharacteristics: phenotypeâ field for each sample.
Project description:Dendritic cells (DC) play critical roles in central and peripheral T cell tolerance. DC found in the steady-state periphery undergo an homeostatic, tolerogenic, maturation that promotes interaction with naive T cells and induction of abortive responses. In contrast, thymic DC are thought to exist solely in an immature state. In this study, we show that XCR1+ thymic DC constitutively mature into a stage characterized by high levels of molecules involved in T cell activation. This unanticipated mature stage corresponded to a third of the XCR1+ thymic DC and fully accounted for their ability to cross-present self-antigens to developing T cells. Transcriptomic analysis of the XCR1+ DC found in thymus and steady-state periphery revealed that their maturation involves profound and convergent changes. Unexpectedly, maturation resulted in down-regulation of genes conferring their specific function on XCR1+ DC. Paradoxically, upon maturation, central and peripheral tolerogenic XCR1+ DC up-regulated many genes thought to drive pro-inflammatory T-cell responses. These events occur independtly of type I interferons and of the microlofora, since the same maturation pattern is observed in XCR1+ tDcs from control, Ifnar1-KO and germ-free mice. Thus, our results reveal that thymic XCR1+ DC undergo constitutive maturation and emphasize the common mechanisms operating for both central and peripheral tolerance induction by XCR1+ DC. DC were isolated from thymus organ as previously described (Luche et al., Eur J Immunol. 2011;41:2165-75.PMID: 21630253), from B6 SPF control, B6 germ-free and Ifnar1-KO mice. DC subsets were sorted by flow cytometry according to the marker combinations described in the Sample records' phenotype field.
Project description:Dendritic cells (DC) play critical roles in central and peripheral T cell tolerance. DC found in the steady-state periphery undergo an homeostatic, tolerogenic, maturation that promotes interaction with naive T cells and induction of abortive responses. In contrast, thymic DC are thought to exist solely in an immature state. In this study, we show that XCR1+ thymic DC constitutively mature into a stage characterized by high levels of molecules involved in T cell activation. This unanticipated mature stage corresponded to a third of the XCR1+ thymic DC and fully accounted for their ability to cross-present self-antigens to developing T cells. Transcriptomic analysis of the XCR1+ DC found in thymus and steady-state periphery revealed that their maturation involves profound and convergent changes. Unexpectedly, maturation resulted in down-regulation of genes conferring their specific function on XCR1+ DC. Paradoxically, upon maturation, central and peripheral tolerogenic XCR1+ DC up-regulated many genes thought to drive pro-inflammatory T-cell responses. These events occur independtly of type I interferons and of the microlofora, since the same maturation pattern is observed in XCR1+ tDcs from control, Ifnar1-KO and germ-free mice. Thus, our results reveal that thymic XCR1+ DC undergo constitutive maturation and emphasize the common mechanisms operating for both central and peripheral tolerance induction by XCR1+ DC.
Project description:Thymic XCR1+ dendritic cells undergo a functional maturation fundamentally similar to that of peripheral tolerogenic XCR1+ dendritic cells
Project description:Dendritic cells (DC) play critical roles in central and peripheral T cell tolerance. DC found in the steady-state periphery undergo an homeostatic, tolerogenic, maturation that promotes interaction with naive T cells and induction of abortive responses. In contrast, thymic DC are thought to exist solely in an immature state. In this study, we show that XCR1+ thymic DC constitutively mature into a stage characterized by high levels of molecules involved in T cell activation. This unanticipated mature stage corresponded to a third of the XCR1+ thymic DC and fully accounted for their ability to cross-present self-antigens to developing T cells. Transcriptomic analysis of the XCR1+ DC found in thymus and steady-state periphery revealed that their maturation involves profound and convergent changes. Unexpectedly, maturation resulted in down-regulation of genes conferring their specific function on XCR1+ DC. Paradoxically, upon maturation, central and peripheral tolerogenic XCR1+ DC up-regulated many genes thought to drive pro-inflammatory T-cell responses. Thus, our results reveal that thymic XCR1+ DC undergo constitutive maturation and emphasize the common mechanisms operating for both central and peripheral tolerance induction by XCR1+ DC.
Project description:XCR1+ dendritic cells (DC) have been shown to excel in antigen cross-presentation for the activation of naïve CD8 T cells. This property was reported to be associated to the subset of the XCR1+ DC expressing IL-12b upon ex vivo stimulation for 24 h with a mixture of CpG, IFN-γ, and GM-CSF (Lin ML et al. Proc Natl Acad Sci USA. 2008. PMID: 18272486). DC found in the steady-state non-lymphoid tissues undergo an homeostatic, tolerogenic, maturation and migrate to the draining lymph nodes to interact with naive autoreactive T cells and induction their peripheral tolerance. In contrast, spleen DC are thought to exist solely in an immature state. The aim of this study was to re-examine heterogeneity within steady state spleen XCR1+ DC, in particular examining whether this population encompass a fraction of mature DCs as assessed through their expression of CCR7 and/or the Il12b gene. Indeed, we show that a small fraction of XCR1+ spleen DC constitutively mature into two distinct but likely successive activation stages characterized as CCR7+ and CCR7+Il12b+ respectively, and correlated with increasing ability to cross-present antigen to naïve CD8 T cells. Transcriptomic analysis of the subsets of XCR1+ DC found in steady state spleen unexpectedly showed that their homeostatic maturation was unexpectedly associated with up-regulated of many genes thought to drive pro-inflammatory T-cell responses and previously found to be commonly induced upon maturation of distinct DC subsets in response to stimulation by various microbial-type stimuli (Vu Manh TP et al. Eur J Immunol. 2013. PMID: 23553052). Thus, our results reveal that spleen XCR1+ DC undergo constitutive maturation and emphasize the common mechanisms operating upon homeostatic, tolerogenic, DC maturation versus microbial-type stimuli-induced, immunogenic, DC maturation. DC were isolated from the spleen of untreated Il12b-EYFP reporter mice (Reinhardt RL et al. J Immunol. 2006. PMID:16849470) mice as previously described (Robbins SH et al. Genome Biol. 2008. PMID: 18218067; Baranek T et al. Cell Host Microbe. 2012. PMID: 23084923). DC subsets were sorted by flow cytometry according to the marker combinations described in the âcharacteristics: phenotypeâ field for each sample.
Project description:XCR1+ dendritic cells (DC) have been shown to excel in antigen cross-presentation for the activation of naïve CD8 T cells. This property was reported to be associated to the subset of the XCR1+ DC expressing IL-12b upon ex vivo stimulation for 24 h with a mixture of CpG, IFN-γ, and GM-CSF (Lin ML et al. Proc Natl Acad Sci USA. 2008. PMID: 18272486). DC found in the steady-state non-lymphoid tissues undergo an homeostatic, tolerogenic, maturation and migrate to the draining lymph nodes to interact with naive autoreactive T cells and induction their peripheral tolerance. In contrast, spleen DC are thought to exist solely in an immature state. The aim of this study was to re-examine heterogeneity within steady state spleen XCR1+ DC, in particular examining whether this population encompass a fraction of mature DCs as assessed through their expression of CCR7 and/or the Il12b gene. Indeed, we show that a small fraction of XCR1+ spleen DC constitutively mature into two distinct but likely successive activation stages characterized as CCR7+ and CCR7+Il12b+ respectively, and correlated with increasing ability to cross-present antigen to naïve CD8 T cells. Transcriptomic analysis of the subsets of XCR1+ DC found in steady state spleen unexpectedly showed that their homeostatic maturation was unexpectedly associated with up-regulated of many genes thought to drive pro-inflammatory T-cell responses and previously found to be commonly induced upon maturation of distinct DC subsets in response to stimulation by various microbial-type stimuli (Vu Manh TP et al. Eur J Immunol. 2013. PMID: 23553052). Thus, our results reveal that spleen XCR1+ DC undergo constitutive maturation and emphasize the common mechanisms operating upon homeostatic, tolerogenic, DC maturation versus microbial-type stimuli-induced, immunogenic, DC maturation.
Project description:XCR1 is known as a signature receptor of type 1 conventional dendritic cells To compare the transcriptomic differences of WT and XCR1 deficient type 1 conventional dendritic cells, we conducted microarry using type 1 conventional dendritic cells from WT and XCR1 KO mice
Project description:The goal of this experiment was to use global gene expression profiling to assess the global genetic reprogramming of spleen XCR1+ DC early after MCMV infection in vivo, using on Affymetrix Mouse Gene 1.0 ST Array. Comparison of the gene expression programs of XCR1+ dendritic cells isolated from the spleen of untreated versus d1.5 MCMV-infected wild-type C57BL/6 mice.
Project description:Functional characterization of human dendritic cell subsets is limited due to the very low frequency of these cells in vivo. We developed an in vitro culture system for the simultaneous generation of XCR1+ DCs and MoDCs from cord blood CD34+ cells. Their global gene expression profiles at steady state and under activation, phenotypes, morphologies and responses to different TLR ligands where characterized and compared with those of their in vivo counterparts. The study demonstrated that the XCR1+ DCs generated in vitro from cord blood CD34+ cells are equivalent to blood XCR1+ DCs and also allowed a rigorous comparison of this DC subset with MoDC which are often considered as the reference model for DCs. Altogether, our results showed that in vitro generated XCR1+ DCs are a better model for the study of blood DC than the conventionally used MoDCs. The different dendritic cell subsets used for the study were either generated in vitro from cord blood CD34+ cells with recombinant human cytokines or isolated from peripheral blood. The subsets were purified by fluorescence-activated cell sorting and their responses to PolyI:C, LPS or R848 were studied including by gene expression profiling.