Project description:Tissue-resident innate lymphoid cells (ILCs) help sustain barrier function and respond to local signals. ILCs are traditionally classified as ILC1, ILC2 or ILC3 on the basis of their expression of specific transcription factors and cytokines1. In the skin, disease-specific production of ILC3-associated cytokines interleukin (IL)-17 and IL-22 in response to IL-23 signalling contributes to dermal inflammation in psoriasis. However, it is not known whether this response is initiated by pre-committed ILCs or by cell-state transitions. Here we show that the induction of psoriasis in mice by IL-23 or imiquimod reconfigures a spectrum of skin ILCs, which converge on a pathogenic ILC3-like state. Tissue-resident ILCs were necessary and sufficient, in the absence of circulatory ILCs, to drive pathology. Single-cell RNA-sequencing (scRNA-seq) profiles of skin ILCs along a time course of psoriatic inflammation formed a dense transcriptional continuum—even at steady state—reflecting fluid ILC states, including a naive or quiescent-like state and an ILC2 effector state. Upon disease induction, the continuum shifted rapidly to span a mixed, ILC3-like subset also expressing cytokines characteristic of ILC2s, which we inferred as arising through multiple trajectories. We confirmed the transition potential of quiescent-like and ILC2 states using in vitro experiments, single-cell assay for transposase-accessible chromatin using sequencing (scATAC-seq) and in vivo fate mapping. Our results highlight the range and flexibility of skin ILC responses, suggesting that immune activities primed in healthy tissues dynamically adapt to provocations and, left unchecked, drive pathological remodelling.
Project description:Regulatory T (Treg) cells can facilitate transplant tolerance and attenuate autoimmune- and inflammatory diseases. Therefore, it is clinically relevant to stimulate Treg cell expansion and function in vivo and to create therapeutic Treg cell products in vitro. We report that TNF receptor 2 (TNFR2) is a unique costimulus for naïve, thymus-derived (t)Treg cells from human blood that promotes their differentiation into non-lymphoid tissue (NLT)-resident effector Treg cells, without Th-like polarization. In contrast, CD28 costimulation maintains a lymphoid tissue (LT)-resident Treg cell phenotype. We base this conclusion on transcriptome and proteome analysis of TNFR2- and CD28-costimulated CD4+ Treg cells and conventional T (Tconv) cells, followed by bioinformatic comparison with published transcriptomic Treg cell signatures from NLT and LT in health and disease, including autoimmunity and cancer. These analyses illuminate that TNFR2 costimulation promotes Treg cell capacity for survival, migration, immunosuppression and tissue regeneration. Functional studies confirmed improved migratory ability of TNFR2-costimulated tTreg cells. Flow cytometry validated the presence of the TNFR2-driven Treg cell signature in effector/memory Treg cells from the human placenta as opposed to blood. Thus, TNFR2 can be exploited as driver of NLT-resident Treg cell differentiation for adoptive cell therapy or antibody-based immunomodulation in human disease.
Project description:Regulatory T (Treg) cells can facilitate transplant tolerance and attenuate autoimmune- and inflammatory diseases. Therefore, it is clinically relevant to stimulate Treg cell expansion and function in vivo and to create therapeutic Treg cell products in vitro. We report that TNF receptor 2 (TNFR2) is a unique costimulus for naïve, thymus-derived (t)Treg cells from human blood that promotes their differentiation into non-lymphoid tissue (NLT)-resident effector Treg cells, without Th-like polarization. In contrast, CD28 costimulation maintains a lymphoid tissue (LT)-resident Treg cell phenotype. We base this conclusion on transcriptome and proteome analysis of TNFR2- and CD28-costimulated CD4+ tTreg cells and conventional T (Tconv) cells, followed by bioinformatic comparison with published transcriptomic Treg cell signatures from NLT and LT in health and disease, including autoimmunity and cancer. These analyses illuminated that TNFR2 costimulation promotes tTreg cell capacity for survival, migration, immunosuppression and tissue regeneration. Functional studies confirmed improved migratory ability of TNFR2-costimulated tTreg cells. Flow cytometry validated the presence of the TNFR2-driven tTreg cell signature in effector/memory Treg cells from the human placenta as opposed to blood. Thus, TNFR2 can be exploited as driver of NLT-resident tTreg cell differentiation for adoptive cell therapy or antibody-based immunomodulation in human disease.
Project description:Tissue-resident memory T (TRM) cells are crucial mediators of adaptive immunity in non-lymphoid tissues. However, the functional heterogeneity and pathogenic roles of CD4+ TRM cells that reside within chronic inflammatory lesions remain unknown. We found that CD69hiCD103low CD4+ TRM cells produced effector cytokines and promoted the inflammation and fibrotic responses induced by chronic exposure to Aspergillus fumigatus. Simultaneously, immunosuppressive CD69hiCD103hiFoxp3+ CD4+ regulatory T (Treg) cells were induced and constrained the ability of pathogenic CD103low TRM cells to cause fibrosis. Thus, lung tissue-resident CD4+ T cells play crucial roles in the pathology of chronic lung inflammation, and CD103 expression defines pathogenic effector and immunosuppressive tissue-resident cell subpopulations in the inflamed lung.
Project description:A primary immune response is typically initiated in secondary lymphoid organs. Virtual memory CD8+ T (TVM) cells are antigen-inexperienced T cells of a central-memory phenotype, acquired through self antigen-driven homeostatic proliferation. Unexpectedly, here we find that, TVM cells are composed of CCR2+ and CCR2- subsets that differentially elaborate a spectrum of effector- and memory-poised functions directly in the tissue. During a primary flu infection, TVM cells rapidly infiltrate the lung in the first day and execute early viral control. TVM cells that recognize viral antigen are retained in the tissue, clonally expand independent of secondary lymphoid organs, and preferentially give rise to tissue-resident memory cells. By orchestrating an extra-lymphoid primary response, heterogenous TVM cells bridge innate reaction and adaptive memory directly in the infected tissue.
Project description:Innate lymphoid cells (ILCs) are considered to be the innate counterparts of adaptive T lymphocytes and play important roles in host defense, tissue repair, metabolic homeostasis, and inflammatory diseases. ILCs are generally thought of as tissue-resident cells, but whether ILCs strictly behave in a tissue-resident manner or can move between sites during infection is unclear. We show here that IL-25- or helminthic infection-induced inflammatory ILC2s are not tissue-resident but circulating cells, which arise from resting ILC2s residing in intestinal lamina propria and then migrate to mesenteric lymph nodes, spleen, lung, and liver. IL-25 induces rapid proliferation of the intestinal ILC2s and a change in their sensitivity to S1P-mediated chemotaxis, leading to lymphatic entry, blood circulation, and accumulation in periphery sites, including the lung where they contribute to anti-helminth defense and tissue repair. Our finding of cytokine-driven expansion and migration of innate lymphocytes, a behavioral parallel to the antigen-driven priming, expansion, and migration of adaptive lymphocytes to effector sites in distant tissues, provides a significant advance in our overall understanding of ILCs and indicates that ILCs complement adaptive immunity by providing both local and distant site effector protection during infection.
Project description:Gut resident IL10+CX3CR1hi macrophages drive development of mucosal tertiary lymphoid structures that serve as ectopic site of the IgA response to enteric infection.
Project description:Subtypes of innate lymphoid cells (ILC), defined by effector function and transcription factor expression, have recently been identified. In the adult, ILC derive from common lymphoid progenitors in bone marrow, although transcriptional regulation of the developmental pathways involved remains poorly defined. TOX is required for development of lymphoid tissue inducer cells, a type of ILC3 required for lymph node organogenesis, and NK cells, a type of ILC1. We show here that production of multiple ILC lineages requires TOX, as a result of TOX-dependent development of common ILC progenitors. Comparative transcriptome analysis demonstrated failure to induce various aspects of the ILC gene program in the absence of TOX, implicating this nuclear factor as a key early determinant of ILC lineage specification. TOX KO vs. wild tyype
Project description:Using two different experimental approaches, we here highlight the long-term residence of a substantial proportion of CD4 Treg and CD4 Tmem cells within the secondary lymphoid organs of specific pathogen-free mice. Microbiota plays an important role in T-cell residence in Peyer’s patches, but only a minor one, if any, in lymph nodes. Lymph node-resident CD4 Treg and CD4 Tmem cells share many phenotypic and functional characteristics, including a core transcriptional profile, with their cell-counterparts from non-lymphoid tissues. In particular, S1PR1 down-regulation may represent the main mechanism accounting for T-cell residency within secondary lymphoid organs. Strikingly, T-cell residence increases with age, to the point that the majority of CD4 Treg and Tmem cells from lymph nodes are in fact, resident T cells in old mice. Altogether, our results show that T-cell residence is not only a hallmark of non-lymphoid tissues, but can be extended to secondary lymphoid organs.