ABSTRACT
The lymphocyte family has expanded significantly in recent years to include not only the adaptive lymphocytes (T cells, B cells) and NK cells, but also several additional innate lymphoid cell (ILC) types. ILCs lack clonally distributed antigen receptors characteristic of adaptive lymphocytes and instead respond exclusively to signaling via germline-encoded receptors. ILCs resemble T cells more closely than any other leukocyte lineage at the transcriptome level and express many elements of the core T cell transcriptional program, including Notch, Gata3, Tcf7, and Bcl11b. We present our current understanding of the shared and distinct transcriptional regulatory mechanisms involved in the development of adaptive T lymphocytes and closely related ILCs. We discuss the possibility that a core set of transcriptional regulators common to ILCs and T cells establish enhancers that enable implementation of closely aligned effector pathways. Studies of the transcriptional regulation of lymphopoiesis will support the development of novel therapeutic approaches to correct early lymphoid developmental defects and aberrant lymphocyte function.
Subject(s)
Adaptive Immunity/genetics , Cell Lineage/genetics , Gene Expression Regulation , Immunity, Innate/genetics , Lymphocytes/immunology , Lymphocytes/metabolism , Transcription, Genetic , Animals , Cell Differentiation , Humans , Lymphocytes/cytology , Lymphoid Progenitor Cells/cytology , Lymphoid Progenitor Cells/metabolismABSTRACT
Natural killer (NK) cells function by eliminating virus-infected or tumor cells. Here we identified an NK-lineage-biased progenitor population, referred to as early NK progenitors (ENKPs), which developed into NK cells independently of common precursors for innate lymphoid cells (ILCPs). ENKP-derived NK cells (ENKP_NK cells) and ILCP-derived NK cells (ILCP_NK cells) were transcriptionally different. We devised combinations of surface markers that identified highly enriched ENKP_NK and ILCP_NK cell populations in wild-type mice. Furthermore, Ly49H+ NK cells that responded to mouse cytomegalovirus infection primarily developed from ENKPs, whereas ILCP_NK cells were better IFNγ producers after infection with Salmonella and herpes simplex virus. Human CD56dim and CD56bright NK cells were transcriptionally similar to ENKP_NK cells and ILCP_NK cells, respectively. Our findings establish the existence of two pathways of NK cell development that generate functionally distinct NK cell subsets in mice and further suggest these pathways may be conserved in humans.
Subject(s)
Cell Differentiation , Killer Cells, Natural , Killer Cells, Natural/immunology , Animals , Mice , Humans , Cell Differentiation/immunology , Mice, Inbred C57BL , Immunity, Innate , CD56 Antigen/metabolism , Muromegalovirus/immunology , Cell Lineage/immunology , Interferon-gamma/metabolism , Interferon-gamma/immunology , Lymphoid Progenitor Cells/metabolism , Lymphoid Progenitor Cells/cytology , Lymphoid Progenitor Cells/immunology , Mice, Knockout , Cells, CulturedABSTRACT
Natural killer (NK) cells are innate lymphoid cells (ILCs) contributing to immune responses to microbes and tumors. Historically, their classification hinged on a limited array of surface protein markers. Here, we used single-cell RNA sequencing (scRNA-seq) and cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) to dissect the heterogeneity of NK cells. We identified three prominent NK cell subsets in healthy human blood: NK1, NK2 and NK3, further differentiated into six distinct subgroups. Our findings delineate the molecular characteristics, key transcription factors, biological functions, metabolic traits and cytokine responses of each subgroup. These data also suggest two separate ontogenetic origins for NK cells, leading to divergent transcriptional trajectories. Furthermore, we analyzed the distribution of NK cell subsets in the lung, tonsils and intraepithelial lymphocytes isolated from healthy individuals and in 22 tumor types. This standardized terminology aims at fostering clarity and consistency in future research, thereby improving cross-study comparisons.
Subject(s)
Killer Cells, Natural , Single-Cell Analysis , Humans , Single-Cell Analysis/methods , Killer Cells, Natural/immunology , Transcriptome , Neoplasms/immunology , Lymphocyte Subsets/immunology , Lymphocyte Subsets/metabolism , Palatine Tonsil/immunology , Palatine Tonsil/cytology , Gene Expression Profiling , Lung/immunology , Cytokines/metabolismABSTRACT
Increasing evidence indicates close interaction between immune cells and the brain, revising the traditional view of the immune privilege of the brain. However, the specific mechanisms by which immune cells promote normal neural function are not entirely understood. Mucosal-associated invariant T cells (MAIT cells) are a unique type of innate-like T cell with molecular and functional properties that remain to be better characterized. In the present study, we report that MAIT cells are present in the meninges and express high levels of antioxidant molecules. MAIT cell deficiency in mice results in the accumulation of reactive oxidative species in the meninges, leading to reduced expression of junctional protein and meningeal barrier leakage. The presence of MAIT cells restricts neuroinflammation in the brain and preserves learning and memory. Together, our work reveals a new functional role for MAIT cells in the meninges and suggests that meningeal immune cells can help maintain normal neural function by preserving meningeal barrier homeostasis and integrity.
Subject(s)
Mucosal-Associated Invariant T Cells , Animals , Mice , Brain , Meninges , Cognition , Oxidative StressABSTRACT
The immune system encodes information about the severity of a pathogenic threat in the quantity and type of memory cells it forms. This encoding emerges from lymphocyte decisions to maintain or lose self-renewal and memory potential during a challenge. By tracking CD8+ T cells at the single-cell and clonal lineage level using time-resolved transcriptomics, quantitative live imaging, and an acute infection model, we find that T cells will maintain or lose memory potential early after antigen recognition. However, following pathogen clearance, T cells may regain memory potential if initially lost. Mechanistically, this flexibility is implemented by a stochastic cis-epigenetic switch that tunably and reversibly silences the memory regulator, TCF1, in response to stimulation. Mathematical modeling shows how this flexibility allows memory T cell numbers to scale robustly with pathogen virulence and immune response magnitudes. We propose that flexibility and stochasticity in cellular decisions ensure optimal immune responses against diverse threats.
Subject(s)
CD8-Positive T-Lymphocytes , Memory T Cells , Epigenesis, Genetic , Clone Cells , Immunologic Memory , Cell DifferentiationABSTRACT
Group 3 innate lymphoid cells (ILC3) are the major subset of gut-resident ILC with essential roles in infections and tissue repair, but how they adapt to the gut environment to maintain tissue residency is unclear. We report that Tox2 is critical for gut ILC3 maintenance and function. Gut ILC3 highly expressed Tox2, and depletion of Tox2 markedly decreased ILC3 in gut but not at central sites, resulting in defective control of Citrobacter rodentium infection. Single-cell transcriptional profiling revealed decreased expression of Hexokinase-2 in Tox2-deficient gut ILC3. Consistent with the requirement for hexokinases in glycolysis, Tox2-/- ILC3 displayed decreased ability to utilize glycolysis for protein translation. Ectopic expression of Hexokinase-2 rescued Tox2-/- gut ILC3 defects. Hypoxia and interleukin (IL)-17A each induced Tox2 expression in ILC3, suggesting a mechanism by which ILC3 adjusts to fluctuating environments by programming glycolytic metabolism. Our results reveal the requirement for Tox2 to support the metabolic adaptation of ILC3 within the gastrointestinal tract.
Subject(s)
Citrobacter rodentium , Enterobacteriaceae Infections , Glycolysis , HMGB Proteins , Immunity, Innate , Lymphocytes , Mice, Knockout , Animals , Mice , Adaptation, Physiological/immunology , Citrobacter rodentium/immunology , Enterobacteriaceae Infections/immunology , Gastrointestinal Tract/immunology , Gastrointestinal Tract/metabolism , Hexokinase/metabolism , Hexokinase/genetics , Interleukin-17/metabolism , Lymphocytes/immunology , Lymphocytes/metabolism , Mice, Inbred C57BL , Trans-Activators/metabolism , Trans-Activators/genetics , HMGB Proteins/genetics , HMGB Proteins/immunology , HMGB Proteins/metabolismABSTRACT
Dietary components and metabolites have a profound impact on immunity and inflammation. Here, we investigated how sensing of cholesterol metabolite oxysterols by γδ T cells impacts their tissue residency and function. We show that dermal IL-17-producing γδ T (Tγδ17) cells essential for skin-barrier homeostasis require oxysterols sensing through G protein receptor 183 (GPR183) for their development and inflammatory responses. Single-cell transcriptomics and murine reporter strains revealed that GPR183 on developing γδ thymocytes is needed for their maturation by sensing medullary thymic epithelial-cell-derived oxysterols. In the skin, basal keratinocytes expressing the oxysterol enzyme cholesterol 25-hydroxylase (CH25H) maintain dermal Tγδ17 cells. Diet-driven increases in oxysterols exacerbate Tγδ17-cell-mediated psoriatic inflammation, dependent on GPR183 on γδ T cells. Hence, cholesterol-derived oxysterols control spatially distinct but biologically linked processes of thymic education and peripheral function of dermal T cells, implicating diet as a focal parameter of dermal Tγδ17 cells.
Subject(s)
Cholesterol, Dietary , Oxysterols , Humans , Animals , Mice , Oxysterols/metabolism , Skin/metabolism , Inflammation , GTP-Binding Proteins/metabolism , Receptors, Antigen, T-Cell, gamma-delta/metabolism , Receptors, G-Protein-Coupled/metabolismABSTRACT
Innate lymphoid cells (ILCs) play important functions in immunity and tissue homeostasis, but their development is poorly understood. Through the use of single-cell approaches, we examined the transcriptional and functional heterogeneity of ILC progenitors, and studied the precursor-product relationships that link the subsets identified. This analysis identified two successive stages of ILC development within T cell factor 1-positive (TCF-1+) early innate lymphoid progenitors (EILPs), which we named 'specified EILPs' and 'committed EILPs'. Specified EILPs generated dendritic cells, whereas this potential was greatly decreased in committed EILPs. TCF-1 was dispensable for the generation of specified EILPs, but required for the generation of committed EILPs. TCF-1 used a pre-existing regulatory landscape established in upstream lymphoid precursors to bind chromatin in EILPs. Our results provide insight into the mechanisms by which TCF-1 promotes developmental progression of ILC precursors, while constraining their dendritic cell lineage potential and enforcing commitment to ILC fate.
Subject(s)
Cell Lineage/immunology , Dendritic Cells/cytology , Hepatocyte Nuclear Factor 1-alpha/immunology , Lymphoid Progenitor Cells/cytology , T-Lymphocytes/cytology , Animals , Cell Differentiation/immunology , Cells, Cultured , Gene Expression Regulation/genetics , Hepatocyte Nuclear Factor 1-alpha/genetics , Mice , Mice, Inbred C57BL , Transcription, Genetic/geneticsABSTRACT
Stem cells are maintained by transcriptional programs that promote self-renewal and repress differentiation. Here, we found that the transcription factor c-Myb was essential for generating and maintaining stem cells in the CD8+ T cell memory compartment. Following viral infection, CD8+ T cells lacking Myb underwent terminal differentiation and generated fewer stem cell-like central memory cells than did Myb-sufficient T cells. c-Myb acted both as a transcriptional activator of Tcf7 (which encodes the transcription factor Tcf1) to enhance memory development and as a repressor of Zeb2 (which encodes the transcription factor Zeb2) to hinder effector differentiation. Domain-mutagenesis experiments revealed that the transactivation domain of c-Myb was necessary for restraining differentiation, whereas its negative regulatory domain was critical for cell survival. Myb overexpression enhanced CD8+ T cell memory formation, polyfunctionality and recall responses that promoted curative antitumor immunity after adoptive transfer. These findings identify c-Myb as a pivotal regulator of CD8+ T cell stemness and highlight its therapeutic potential.
Subject(s)
CD8-Positive T-Lymphocytes/immunology , Immunologic Memory/immunology , Neoplasms, Experimental/immunology , Proto-Oncogene Proteins c-myb/immunology , Stem Cells/immunology , Animals , CD8-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/virology , Cell Differentiation/immunology , Cell Line, Tumor , HEK293 Cells , Humans , Immunologic Memory/genetics , Lymphocytic Choriomeningitis/immunology , Lymphocytic Choriomeningitis/metabolism , Lymphocytic Choriomeningitis/virology , Lymphocytic choriomeningitis virus/immunology , Lymphocytic choriomeningitis virus/physiology , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , Neoplasms, Experimental/metabolism , Neoplasms, Experimental/virology , Proto-Oncogene Proteins c-myb/genetics , Proto-Oncogene Proteins c-myb/metabolism , Stem Cells/metabolism , Stem Cells/virology , T Cell Transcription Factor 1/genetics , T Cell Transcription Factor 1/immunology , T Cell Transcription Factor 1/metabolismABSTRACT
The differentiation of innate lymphoid cells (ILCs) from hematopoietic stem cells needs to go through several multipotent progenitor stages. However, it remains unclear whether the fates of multipotent progenitors are predefined by epigenetic states. Here, we report the identification of distinct accessible chromatin regions in all lymphoid progenitors (ALPs), EILPs, and ILC precursors (ILCPs). Single-cell MNase-seq analyses revealed that EILPs contained distinct subpopulations epigenetically primed toward either dendritic cell lineages or ILC lineages. We found that TCF-1 and GATA3 co-bound to the lineage-defining sites for ILCs (LDS-Is), whereas PU.1 binding was enriched in the LDSs for alternative dendritic cells (LDS-As). TCF-1 and GATA3 were indispensable for the epigenetic priming of LDSs at the EILP stage. Our results suggest that the multipotency of progenitor cells is defined by the existence of a heterogeneous population of cells epigenetically primed for distinct downstream lineages, which are regulated by key transcription factors.
Subject(s)
Immunity, Innate , Lymphocytes , Cell Differentiation , Cell Lineage , Epigenesis, Genetic , Hematopoietic Stem CellsABSTRACT
Plasma cells produce large quantities of antibodies and so play essential roles in immune protection1. Plasma cells, including a long-lived subset, reside in the bone marrow where they depend on poorly defined microenvironment-linked survival signals1. We show that bone marrow plasma cells use the ligand-gated purinergic ion channel P2RX4 to sense extracellular ATP released by bone marrow osteoblasts through the gap-junction protein pannexin 3 (PANX3). Mutation of Panx3 or P2rx4 each caused decreased serum antibodies and selective loss of bone marrow plasma cells. Compared to their wild-type counterparts, PANX3-null osteoblasts secreted less extracellular ATP and failed to support plasma cells in vitro. The P2RX4-specific inhibitor 5-BDBD abrogated the impact of extracellular ATP on bone marrow plasma cells in vitro, depleted bone marrow plasma cells in vivo and reduced pre-induced antigen-specific serum antibody titre with little posttreatment rebound. P2RX4 blockade also reduced autoantibody titre and kidney disease in two mouse models of humoral autoimmunity. P2RX4 promotes plasma cell survival by regulating endoplasmic reticulum homeostasis, as short-term P2RX4 blockade caused accumulation of endoplasmic reticulum stress-associated regulatory proteins including ATF4 and B-lineage mutation of the pro-apoptotic ATF4 target Chop prevented bone marrow plasma cell demise on P2RX4 inhibition. Thus, generating mature protective and pathogenic plasma cells requires P2RX4 signalling controlled by PANX3-regulated extracellular ATP release from bone marrow niche cells.
Subject(s)
Adenosine Triphosphate , Bone Marrow Cells , Plasma Cells , Animals , Mice , Adenosine Triphosphate/metabolism , Autoantibodies/immunology , Autoimmunity/immunology , Bone Marrow Cells/cytology , Bone Marrow Cells/metabolism , Cell Lineage , Connexins/genetics , Connexins/metabolism , Endoplasmic Reticulum/metabolism , Endoplasmic Reticulum Stress , Mutation , Osteoblasts/metabolism , Plasma Cells/cytology , Plasma Cells/immunology , Plasma Cells/metabolism , Receptors, Purinergic P2X4/metabolism , Signal TransductionABSTRACT
Regulatory elements activate promoters by recruiting transcription factors (TFs) to specific motifs. Notably, TF-DNA interactions often depend on cooperativity with colocalized partners, suggesting an underlying cis-regulatory syntax. To explore TF cooperativity in mammals, we analyze â¼500 mouse and human primary cells by combining an atlas of TF motifs, footprints, ChIP-seq, transcriptomes, and accessibility. We uncover two TF groups that colocalize with most expressed factors, forming stripes in hierarchical clustering maps. The first group includes lineage-determining factors that occupy DNA elements broadly, consistent with their key role in tissue-specific transcription. The second one, dubbed universal stripe factors (USFs), comprises â¼30 SP, KLF, EGR, and ZBTB family members that recognize overlapping GC-rich sequences in all tissues analyzed. Knockouts and single-molecule tracking reveal that USFs impart accessibility to colocalized partners and increase their residence time. Mammalian cells have thus evolved a TF superfamily with overlapping DNA binding that facilitate chromatin accessibility.
Subject(s)
Chromatin , Transcription Factors , Animals , Binding Sites , Chromatin/genetics , DNA/genetics , Humans , Mammals/genetics , Mammals/metabolism , Mice , Mice, Knockout , Protein Binding , Transcription Factors/metabolismABSTRACT
Maui, Hawaii, was the home for the latest Global Thymus Network meeting 5-9 June 2016. Participants gathered together to discuss how one little organ can have such huge effects.
Subject(s)
Allergy and Immunology , Cancer Vaccines/immunology , Immunotherapy, Adoptive , T-Lymphocyte Subsets/immunology , T-Lymphocytes/immunology , Thymus Gland/immunology , Animals , Cell Differentiation , Clonal Selection, Antigen-Mediated , Gene Expression Regulation, Developmental , Hawaii , Humans , Receptors, Antigen, T-Cell/genetics , Regeneration , T-Lymphocytes/transplantation , Translational Research, BiomedicalSubject(s)
Allergy and Immunology , Biomedical Research , Stress, Physiological , T-Lymphocytes/immunology , Thymocytes/immunology , Thymus Gland/immunology , Animals , COVID-19 , Cell Differentiation , Humans , Phenotype , T-Lymphocytes/metabolism , Telecommunications , Thymocytes/metabolism , Thymus Gland/metabolismABSTRACT
The cellular and molecular events that drive the early development of innate lymphoid cells (ILCs) remain poorly understood. We show that the transcription factor TCF-1 is required for the efficient generation of all known adult ILC subsets and their precursors. Using novel reporter mice, we identified a new subset of early ILC progenitors (EILPs) expressing high amounts of TCF-1. EILPs lacked efficient T and B lymphocyte potential but efficiently gave rise to NK cells and all known adult helper ILC lineages, indicating that they are the earliest ILC-committed progenitors identified so far. Our results suggest that upregulation of TCF-1 expression denotes the earliest stage of ILC fate specification. The discovery of EILPs provides a basis for deciphering additional signals that specify ILC fate.
Subject(s)
Bone Marrow Cells/cytology , Bone Marrow Cells/immunology , Immunity, Innate , Lymphocytes/cytology , Lymphocytes/immunology , T Cell Transcription Factor 1/genetics , Up-Regulation , Animals , Cells, Cultured , Flow Cytometry , Mice , Microarray Analysis , T Cell Transcription Factor 1/metabolismABSTRACT
T cell development is orchestrated by transcription factors that regulate the expression of genes initially buried within inaccessible chromatin, but the transcription factors that establish the regulatory landscape of the T cell lineage remain unknown. Profiling chromatin accessibility at eight stages of T cell development revealed the selective enrichment of TCF-1 at genomic regions that became accessible at the earliest stages of development. TCF-1 was further required for the accessibility of these regulatory elements and at the single-cell level, it dictated a coordinate opening of chromatin in T cells. TCF-1 expression in fibroblasts generated de novo chromatin accessibility even at chromatin regions with repressive marks, inducing the expression of T cell-restricted genes. These results indicate that a mechanism by which TCF-1 controls T cell fate is through its widespread ability to target silent chromatin and establish the epigenetic identity of T cells.
Subject(s)
Cell Lineage , Epigenomics , Hepatocyte Nuclear Factor 1-alpha/physiology , T Cell Transcription Factor 1/physiology , T-Lymphocytes/physiology , Animals , Chromatin/physiology , Chromatin Assembly and Disassembly , Fibroblasts/metabolism , Mice , NIH 3T3 Cells , Transcription, GeneticABSTRACT
The thymus is required for the development of both adaptive and innate-like T cell subsets. There is keen interest in manipulating thymic function for therapeutic purposes in circumstances of autoimmunity, immunodeficiency, and for purposes of immunotherapy. Within the thymus, thymic epithelial cells play essential roles in directing T cell development. Several transcription factors are known to be essential for thymic epithelial cell development and function, and a few transcription factors have been studied in considerable detail. However, the role of many other transcription factors is less well understood. Further, it is likely that roles exist for other transcription factors not yet known to be important in thymic epithelial cells. Recent progress in understanding of thymic epithelial cell heterogeneity has provided some new insight into transcriptional requirements in subtypes of thymic epithelial cells. However, it is unknown whether progenitors of thymic epithelial cells exist in the adult thymus, and consequently, developmental relationships linking putative precursors with differentiated cell types are poorly understood. While we do not presently possess a clear understanding of stage-specific requirements for transcription factors in thymic epithelial cells, new single-cell transcriptomic and epigenomic technologies should enable rapid progress in this field. Here, we review our current knowledge of transcription factors involved in the development, maintenance, and function of thymic epithelial cells, and the mechanisms by which they act.
Subject(s)
Epigenesis, Genetic , Epithelial Cells , Cell Differentiation , Epithelial Cells/physiology , Humans , T-Lymphocyte Subsets/metabolism , Thymus Gland , Transcription Factors/geneticsABSTRACT
Notch signaling induces gene expression of the T cell lineage and discourages alternative fate outcomes. Hematopoietic deficiency in the Notch target Hes1 results in severe T cell lineage defects; however, the underlying mechanism is unknown. We found here that Hes1 constrained myeloid gene-expression programs in T cell progenitor cells, as deletion of the myeloid regulator C/EBP-α restored the development of T cells from Hes1-deficient progenitor cells. Repression of Cebpa by Hes1 required its DNA-binding and Groucho-recruitment domains. Hes1-deficient multipotent progenitor cells showed a developmental bias toward myeloid cells and dendritic cells after Notch signaling, whereas Hes1-deficient lymphoid progenitor cells required additional cytokine signaling for diversion into the myeloid lineage. Our findings establish the importance of constraining developmental programs of the myeloid lineage early in T cell development.
Subject(s)
Basic Helix-Loop-Helix Transcription Factors/immunology , CCAAT-Enhancer-Binding Protein-alpha/immunology , Homeodomain Proteins/immunology , Receptor, Notch1/immunology , T-Lymphocytes/immunology , Animals , Basic Helix-Loop-Helix Transcription Factors/genetics , Basic Helix-Loop-Helix Transcription Factors/metabolism , CCAAT-Enhancer-Binding Protein-alpha/genetics , CCAAT-Enhancer-Binding Protein-alpha/metabolism , Cell Line , Cell Lineage/genetics , Cell Lineage/immunology , Cells, Cultured , Cytokines/immunology , Cytokines/metabolism , Dendritic Cells/immunology , Dendritic Cells/metabolism , Female , Flow Cytometry , Gene Expression/immunology , Homeodomain Proteins/genetics , Homeodomain Proteins/metabolism , Lymphopoiesis/genetics , Lymphopoiesis/immunology , Mice , Mice, Inbred C57BL , Mice, Knockout , Mutation , Myeloid Cells/immunology , Myeloid Cells/metabolism , Protein Binding/immunology , Receptor, Notch1/genetics , Receptor, Notch1/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction/genetics , Signal Transduction/immunology , Stem Cells/immunology , Stem Cells/metabolism , T-Lymphocytes/metabolism , Transcription Factor HES-1ABSTRACT
Type 2 innate lymphoid cells (ILC2s) promote anti-helminth responses and contribute to allergies. Here, we report that Bcl11b, previously considered a T-cell-specific transcription factor, acted directly upstream of the key ILC2 transcription factor Gfi1 to maintain its expression in mature ILC2s. Consequently, Bcl11b(-/-) ILC2s downregulated Gata3 and downstream genes, including Il1rl1 (encoding IL-33 receptor), and upregulated Rorc and type 3 ILC (ILC3) genes. Additionally, independent of Gfi1, Bcl11b directly repressed expression of the gene encoding the ILC3 transcription factor Ahr, further contributing to silencing of ILC3 genes in ILC2s. Thus, Bcl11b(-/-) ILC2s lost their functions and gained ILC3 functions, and although they expanded in response to the protease allergen papain, they produced ILC3 but not ILC2 cytokines and caused increased airway infiltration of neutrophils instead of eosinophils. Our results demonstrate that Bcl11b is more than just a T-cell-only transcription factor and establish that Bcl11b sustains mature ILC2 genetic and functional programs and lineage fidelity.