ABSTRACT
The Bacillus Calmette Guerin (BCG) vaccine has been shown to induce non-specific protection against diseases other than tuberculosis in vaccinated individuals, attributed to the induction of trained immunity. We have previously demonstrated that BCG administration induces innate immune training in mixed peripheral blood mononuclear cells and monocytes in calves. Gamma Delta (γδ) T cells are non-conventional T cells that exhibit innate and adaptive immune system features. They are in higher proportion in the peripheral blood of cattle than humans or rodents and play an essential role in bovine immune response to pathogens. In the current study, we determined if BCG administration induced innate immune training in bovine γδ T cells. A group of 16 pre-weaned Holstein calves (2-4 d age) were enrolled in the study and randomly assigned to vaccine and control groups (n=8/group). The vaccine group received two doses of 106 colony forming units (CFU) BCG Danish strain subcutaneously, separated by 2 weeks. The control group remained unvaccinated. Gamma delta T cells were purified from peripheral blood using magnetic cell sorting three weeks after receiving the 1st BCG dose. We observed functional changes in the γδ T cells from BCG-treated calves shown by increased IL-6 and TNF-α cytokine production in response to in vitro stimulation with Escherichia coli LPS and PAM3CSK4. ATAC-Seq analysis of 78,278 regions of open chromatin (peaks) revealed that γδ T cells from BCG-treated calves had an altered epigenetic status compared to cells from the control calves. Differentially accessible peaks (DAP) found near the promoters of innate immunity-related genes like Siglec14, Irf4, Ifna2, Lrrfip1, and Tnfrsf10d were 1 to 4-fold more accessible in cells from BCG-treated calves. MOTIF enrichment analysis of the sequences within DAPs, which explores transcription factor binding motifs (TFBM) upstream of regulatory elements, revealed TFBM for Eomes and IRF-5 were among the most enriched transcription factors. GO enrichment analysis of genes proximal to the DAPs showed enrichment of pathways such as regulation of IL-2 production, T-cell receptor signaling pathway, and other immune regulatory pathways. In conclusion, our study shows that subcutaneous BCG administration in pre-weaned calves can induce innate immune memory in the form of trained immunity in γδ T cells. This memory is associated with increased chromatin accessibility of innate immune response-related genes, thereby inducing a functional trained immune response evidenced by increased IL-6 and TNF-α cytokine production.
Subject(s)
BCG Vaccine , Immunity, Innate , Animals , Cattle , BCG Vaccine/immunology , Receptors, Antigen, T-Cell, gamma-delta/immunology , Receptors, Antigen, T-Cell, gamma-delta/metabolism , Injections, Subcutaneous , Mycobacterium bovis/immunology , Cytokines/metabolism , Intraepithelial Lymphocytes/immunology , Intraepithelial Lymphocytes/metabolism , Vaccination , Immunologic MemoryABSTRACT
Despite the considerable progress in acute myeloid leukemia (AML) treatment, relapse after allogeneic hematopoietic stem cell transplantation (HSCT) is still frequent and associated with a poor prognosis. Relapse has been shown to be correlated with an incomplete eradication of CD34+ leukemic stem cells prior to HSCT. Previously, we have shown that a novel CD34-directed, bispecific T-cell engager (BTE) can efficiently redirect the T-cell effector function toward cancer cells, thus eliminating leukemic cells in vitro and in vivo. However, its impact on γδ T-cells is still unclear. In this study, we tested the efficacy of the CD34-specific BTE using in vitro expanded γδ T-cells as effectors. We showed that the BTEs bind to γδ T-cells and CD34+ leukemic cell lines and induce target cell killing in a dose-dependent manner. Additionally, γδ T-cell mediated killing was found to be superior to αß T-cell mediated cytotoxicity. Furthermore, we observed that only in the presence of BTE the γδ T-cells induced primary AML blast killing in vitro. Importantly, our results show that γδ T-cells did not target the healthy CD34intermediate endothelial blood-brain barrier cell line (hCMEC/D3) nor lysed CD34+ HSCs from healthy bone marrow samples.
Subject(s)
Antibodies, Bispecific , Antigens, CD34 , CD3 Complex , Leukemia, Myeloid, Acute , Receptors, Antigen, T-Cell, gamma-delta , Humans , Antibodies, Bispecific/pharmacology , Antibodies, Bispecific/therapeutic use , Leukemia, Myeloid, Acute/immunology , Leukemia, Myeloid, Acute/therapy , Leukemia, Myeloid, Acute/pathology , Leukemia, Myeloid, Acute/metabolism , Antigens, CD34/metabolism , CD3 Complex/immunology , Receptors, Antigen, T-Cell, gamma-delta/metabolism , Receptors, Antigen, T-Cell, gamma-delta/immunology , Lymphocyte Activation/immunology , Cell Line, Tumor , Cytotoxicity, Immunologic , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , Intraepithelial Lymphocytes/immunology , Intraepithelial Lymphocytes/metabolismABSTRACT
Butyrophilin (BTN) molecules are emerging as key regulators of T cell immunity; however, how they trigger cell-mediated responses is poorly understood. Here, the crystal structure of a gamma-delta T cell antigen receptor (γδTCR) in complex with BTN2A1 revealed that BTN2A1 engages the side of the γδTCR, leaving the apical TCR surface bioavailable. We reveal that a second γδTCR ligand co-engages γδTCR via binding to this accessible apical surface in a BTN3A1-dependent manner. BTN2A1 and BTN3A1 also directly interact with each other in cis, and structural analysis revealed formation of W-shaped heteromeric multimers. This BTN2A1-BTN3A1 interaction involved the same epitopes that BTN2A1 and BTN3A1 each use to mediate the γδTCR interaction; indeed, locking BTN2A1 and BTN3A1 together abrogated their interaction with γδTCR, supporting a model wherein the two γδTCR ligand-binding sites depend on accessibility to cryptic BTN epitopes. Our findings reveal a new paradigm in immune activation, whereby γδTCRs sense dual epitopes on BTN complexes.
Subject(s)
Butyrophilins , Receptors, Antigen, T-Cell, gamma-delta , Butyrophilins/metabolism , Butyrophilins/immunology , Butyrophilins/chemistry , Receptors, Antigen, T-Cell, gamma-delta/immunology , Receptors, Antigen, T-Cell, gamma-delta/metabolism , Humans , Protein Binding , Protein Multimerization , Antigens, CD/metabolism , Antigens, CD/immunology , Antigens, CD/chemistry , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , Crystallography, X-Ray , Lymphocyte Activation/immunology , Models, Molecular , Intraepithelial Lymphocytes/immunology , Intraepithelial Lymphocytes/metabolismABSTRACT
Gamma delta (γδ) T cells are a heterogeneous population of cells that play roles in inflammation, host tissue repair, clearance of viral and bacterial pathogens, regulation of immune processes, and tumor surveillance. Recent research suggests that these are the main skin cells that produce interleukin-17 (I-17). Furthermore, γδ T cells exhibit memory-cell-like characteristics that mediate repeated episodes of psoriatic inflammation. γδ T cells are found in epithelial tissues, where many cancers develop. There, they participate in antitumor immunity as cytotoxic cells or as immune coordinators. γδ T cells also participate in host defense, immune surveillance, and immune homeostasis. The aim of this review is to present the importance of γδ T cells in physiological and pathological diseases, such as psoriasis, atopic dermatitis, autoimmune diseases, cancer, and lymphoma.
Subject(s)
Autoimmune Diseases , Dermatitis, Atopic , Intraepithelial Lymphocytes , Lymphoma , Psoriasis , Humans , Psoriasis/immunology , Psoriasis/pathology , Dermatitis, Atopic/immunology , Dermatitis, Atopic/pathology , Autoimmune Diseases/immunology , Autoimmune Diseases/metabolism , Intraepithelial Lymphocytes/immunology , Intraepithelial Lymphocytes/metabolism , Animals , Lymphoma/immunology , Lymphoma/pathology , Receptors, Antigen, T-Cell, gamma-delta/metabolism , Receptors, Antigen, T-Cell, gamma-delta/immunology , Neoplasms/immunology , Neoplasms/pathologyABSTRACT
Triple-negative breast cancer (TNBC) is a subtype of breast cancer that presents significant therapeutic challenges due to the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression. As a result, conventional hormonal and targeted therapies are largely ineffective, underscoring the urgent need for novel treatment strategies. γδT cells, known for their robust anti-tumor properties, show considerable potential in TNBC treatment as they can identify and eliminate tumor cells without reliance on MHC restrictions. These cells demonstrate extensive proliferation both in vitro and in vivo, and can directly target tumors through cytotoxic effects or indirectly by promoting other immune responses. Studies suggest that expansion and adoptive transfer strategies targeting Vδ2 and Vδ1 γδT cell subtypes have shown promise in preclinical TNBC models. This review compiles and discusses the existing literature on the primary subgroups of γδT cells, their roles in cancer therapy, their contributions to tumor cell cytotoxicity and immune modulation, and proposes potential strategies for future γδT cell-based immunotherapies in TNBC.
Subject(s)
Triple Negative Breast Neoplasms , Humans , Triple Negative Breast Neoplasms/immunology , Triple Negative Breast Neoplasms/therapy , Animals , Female , Receptors, Antigen, T-Cell, gamma-delta/immunology , Receptors, Antigen, T-Cell, gamma-delta/metabolism , Intraepithelial Lymphocytes/immunology , Intraepithelial Lymphocytes/metabolism , Immunotherapy, Adoptive/methods , Immunotherapy/methodsABSTRACT
Atherosclerosis poses a significant threat to human health, impacting overall well-being and imposing substantial financial burdens. Current treatment strategies mainly focus on managing low-density lipids (LDL) and optimizing liver functions. However, it's crucial to recognize that Atherosclerosis involves more than just lipid accumulation; it entails a complex interplay of immune responses. Research highlights the pivotal role of lipid-laden macrophages in the formation of atherosclerotic plaques. These macrophages attract lymphocytes like CD4 and CD8 to the inflamed site, potentially intensifying the inflammatory response. γδ T lymphocytes, with their diverse functions in innate and adaptive immune responses, pathogen defense, antigen presentation, and inflammation regulation, have been implicated in the early stages of Atherosclerosis. However, our understanding of the roles of γδ T cells in Atherosclerosis remains limited. This mini-review aims to shed light on the characteristics and functions of γδ T cells in Atherosclerosis. By gaining insights into the roles of γδ T cells, we may uncover a promising strategy to mitigate plaque buildup and dampen the inflammatory response, thereby opening new avenues for effectively managing this condition.
Subject(s)
Atherosclerosis , Receptors, Antigen, T-Cell, gamma-delta , Humans , Atherosclerosis/immunology , Atherosclerosis/metabolism , Animals , Receptors, Antigen, T-Cell, gamma-delta/metabolism , Receptors, Antigen, T-Cell, gamma-delta/immunology , Macrophages/immunology , Macrophages/metabolism , Plaque, Atherosclerotic/immunology , Intraepithelial Lymphocytes/immunology , Intraepithelial Lymphocytes/metabolism , Immunity, Innate , T-Lymphocyte Subsets/immunology , T-Lymphocyte Subsets/metabolism , Inflammation/immunology , Adaptive ImmunityABSTRACT
The contribution of γδ T cells to immune responses is associated with rapid secretion of interferon-γ (IFN-γ). Here, we show a perinatal thymic wave of innate IFN-γ-producing γδ T cells that express CD8αß heterodimers and expand in preclinical models of infection and cancer. Optimal CD8αß+ γδ T cell development is directed by low T cell receptor signaling and through provision of interleukin (IL)-4 and IL-7. This population is pathologically relevant as overactive, or constitutive, IL-7R-STAT5B signaling promotes a supraphysiological accumulation of CD8αß+ γδ T cells in the thymus and peripheral lymphoid organs in two mouse models of T cell neoplasia. Likewise, CD8αß+ γδ T cells define a distinct subset of human T cell acute lymphoblastic leukemia pediatric patients. This work characterizes the normal and malignant development of CD8αß+ γδ T cells that are enriched in early life and contribute to innate IFN-γ responses to infection and cancer.
Subject(s)
Immunity, Innate , Interferon-gamma , Receptors, Antigen, T-Cell, gamma-delta , Receptors, Interleukin-7 , STAT5 Transcription Factor , Thymus Gland , Animals , Interferon-gamma/metabolism , Interferon-gamma/immunology , Mice , Humans , Receptors, Antigen, T-Cell, gamma-delta/metabolism , Receptors, Antigen, T-Cell, gamma-delta/immunology , Thymus Gland/immunology , Receptors, Interleukin-7/metabolism , STAT5 Transcription Factor/metabolism , Signal Transduction/immunology , Mice, Inbred C57BL , CD8-Positive T-Lymphocytes/immunology , Mice, Knockout , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Receptors, Antigen, T-Cell, alpha-beta/genetics , CD8 Antigens/metabolism , Female , Intraepithelial Lymphocytes/immunology , Intraepithelial Lymphocytes/metabolism , Interleukin-7/metabolismABSTRACT
OBJECTIVES: γδ T-lymphocytes play a role in angiotensin II (AngII)-induced hypertension, vascular injury and T-cell infiltration in perivascular adipose tissue (PVAT) in mice. Mesenteric arteries of hypertensive mice and subcutaneous arteries from obese humans present similar remodeling. We hypothesized that γδ T-cell subtypes in mesenteric vessels with PVAT (MV/PVAT) from hypertensive mice and subcutaneous adipose tissue (SAT) from obese humans, who are prone to develop hypertension, would be similar. METHODS: Mice were infused with AngII for 14âdays. MV/PVAT T-cells were used for single-cell RNA-sequencing (scRNA-seq). scRNA-seq data (GSE155960) of SAT CD45 + cells from three lean and three obese women were downloaded from the Gene Expression Omnibus database. RESULTS: δ T-cell subclustering identified six δ T-cell subtypes. AngII increased T-cell receptor δ variable 4 ( Trdv4 ) + γδ T-effector memory cells and Cd28high δ T EM -cells, changes confirmed by flow cytometry. δ T-cell subclustering identified nine δ T-cell subtypes in human SAT. CD28 expressing δ T-cell subclustering demonstrated similar δ T-cell subpopulations in murine MV/PVAT and human SAT. Cd28+ γδ NKT EM and Cd28high δ T EM -cells increased in MV/PVAT from hypertensive mice and CD28high δ T EM -cells in SAT from obese women compared to the lean women. CONCLUSION: Similar CD28 + δ T-cells were identified in murine MV/PVAT and human SAT. CD28 high δ T EM -cells increased in MV/PVAT in hypertensive mice and in SAT from humans with obesity, a prehypertensive condition. CD28 + δ T-lymphocytes could have a pathogenic role in human hypertension associated with obesity, and could be a potential target for therapy.
Subject(s)
CD28 Antigens , Hypertension , Obesity , Subcutaneous Fat , Animals , Humans , Hypertension/immunology , Hypertension/metabolism , Mice , Subcutaneous Fat/metabolism , CD28 Antigens/metabolism , Female , Male , Angiotensin II , Intraepithelial Lymphocytes/immunology , Intraepithelial Lymphocytes/metabolism , Adipose Tissue/metabolismABSTRACT
Intraepithelial lymphocytes (IELs) are T cells important for the maintenance of barrier integrity in the intestine. Colon IELs are significantly reduced in both MyD88-deficient mice and those lacking an intact microbiota, suggesting that MyD88-mediated detection of bacterial products is important for the recruitment and/or retention of these cells. Here, using conditionally deficient MyD88 mice, we show that myeloid cells are the key mediators of TCRαß+ IEL recruitment to the colon. Upon exposure to luminal bacteria, myeloid cells produce sphingosine-1-phosphate (S1P) in a MyD88-dependent fashion. TCRαß+ IEL recruitment may be blocked using the S1P receptor antagonist FTY720, confirming the importance of S1P in the recruitment of TCRαß+ IELs to the colon epithelium. Finally, using the TNFΔARE/+ model of Crohn's-like bowel inflammation, we show that disruption of colon IEL recruitment through myeloid-specific MyD88 deficiency results in reduced pathology. Our results illustrate one mechanism for recruitment of a subset of IELs to the colon.
Subject(s)
Colon , Intestinal Mucosa , Intraepithelial Lymphocytes , Lysophospholipids , Mice, Knockout , Myeloid Cells , Myeloid Differentiation Factor 88 , Receptors, Antigen, T-Cell, alpha-beta , Sphingosine , Animals , Lysophospholipids/metabolism , Mice , Sphingosine/analogs & derivatives , Sphingosine/metabolism , Colon/immunology , Myeloid Differentiation Factor 88/metabolism , Myeloid Cells/immunology , Myeloid Cells/metabolism , Intestinal Mucosa/immunology , Intestinal Mucosa/metabolism , Intraepithelial Lymphocytes/immunology , Intraepithelial Lymphocytes/metabolism , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Receptors, Antigen, T-Cell, alpha-beta/genetics , Mice, Inbred C57BL , Fingolimod Hydrochloride/pharmacology , Crohn Disease/immunologySubject(s)
Antibodies, Monoclonal , CD4-Positive T-Lymphocytes , Triple Negative Breast Neoplasms , Humans , Female , Triple Negative Breast Neoplasms/drug therapy , Triple Negative Breast Neoplasms/immunology , Antibodies, Monoclonal/therapeutic use , Antibodies, Monoclonal/pharmacology , CD4-Positive T-Lymphocytes/drug effects , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/metabolism , Antineoplastic Agents, Immunological/therapeutic use , Antineoplastic Agents, Immunological/pharmacology , Middle Aged , Intraepithelial Lymphocytes/drug effects , Intraepithelial Lymphocytes/immunology , Intraepithelial Lymphocytes/metabolismABSTRACT
Tumor-infiltrating lymphocytes (TILs) are associated with improved survival in patients with epithelial ovarian cancer. However, TIL evaluation has not been used in routine clinical practice because of reproducibility issues. The current study developed two convolutional neural network models to detect TILs and to determine their spatial location in whole slide images, and established a spatial assessment pipeline to objectively quantify intraepithelial and stromal TILs in patients with high-grade serous ovarian carcinoma. The predictions of the established models showed a significant positive correlation with the number of CD8+ T cells and immune gene expressions. Patients with a higher density of intraepithelial TILs had a significantly prolonged overall survival and progression-free survival in multiple cohorts. On the basis of the density of intraepithelial and stromal TILs, patients were classified into three immunophenotypes: immune inflamed, excluded, and desert. The immune-desert subgroup showed the worst prognosis. Gene expression analysis showed that the immune-desert subgroup had lower immune cytolytic activity and T-cell-inflamed gene-expression profile scores, whereas the immune-excluded subgroup had higher expression of interferon-γ and programmed death 1 receptor signaling pathway. The established evaluation method provided detailed and comprehensive quantification of intraepithelial and stromal TILs throughout hematoxylin and eosin-stained slides. It has potential for clinical application for personalized treatment of patients with ovarian cancer.
Subject(s)
Cystadenocarcinoma, Serous , Deep Learning , Lymphocytes, Tumor-Infiltrating , Ovarian Neoplasms , Humans , Female , Lymphocytes, Tumor-Infiltrating/immunology , Lymphocytes, Tumor-Infiltrating/pathology , Ovarian Neoplasms/immunology , Ovarian Neoplasms/pathology , Ovarian Neoplasms/genetics , Cystadenocarcinoma, Serous/pathology , Cystadenocarcinoma, Serous/immunology , Cystadenocarcinoma, Serous/genetics , Middle Aged , Aged , Prognosis , Stromal Cells/pathology , Stromal Cells/immunology , Stromal Cells/metabolism , Intraepithelial Lymphocytes/immunology , Intraepithelial Lymphocytes/metabolismABSTRACT
γδ T cells play an important role in disease control in acute myeloid leukemia (AML) and have become an emerging area of therapeutic interest. These cells represent a minor population of T lymphocytes with intrinsic abilities to recognize antigens in a major histocompatibility complex-independent manner and functionally straddle the innate and adaptive immunity interface. AML shows high expression of phosphoantigens and UL-16 binding proteins that activate the Vδ2 and Vδ1 subtypes of γδ T cells, respectively, leading to γδ T cell-mediated cytotoxicity. Insights from murine models and clinical data in humans show improved overall survival, leukemia-free survival, reduced risk of relapse, enhanced graft-versus-leukemia effect, and decreased graft-versus-host disease in patients with AML who have higher reconstitution of γδ T cells following allogeneic hematopoietic stem cell transplantation. Clinical trials leveraging γδ T cell biology have used unmodified and modified allogeneic cells as well as bispecific engagers and monoclonal antibodies. In this review, we discuss γδ T cells' biology, roles in cancer and AML, and mechanisms of immune escape and antileukemia effect; we also discuss recent clinical advances related to γδ T cells in the field of AML therapeutics.
Subject(s)
Graft vs Host Disease , Intraepithelial Lymphocytes , Leukemia, Myeloid, Acute , Humans , Animals , Mice , Intraepithelial Lymphocytes/metabolism , Receptors, Antigen, T-Cell, gamma-delta/metabolism , Leukemia, Myeloid, Acute/therapy , BiologyABSTRACT
TCRαß+CD8αα+ intraepithelial lymphocytes (CD8αα+ αß IELs) are a specialized subset of T cells in the gut epithelium that develop from thymic agonist selected IEL precursors (IELps). The molecular mechanisms underlying the selection and differentiation of this T cell type in the thymus are largely unknown. Here, we found that Bcl6 deficiency in αß T cells resulted in the near absence of CD8αα+ αß IELs. BCL6 was expressed by approximately 50% of CD8αα+ αß IELs and by the majority of thymic PD1+ IELps after agonist selection. Bcl6 deficiency blocked early IELp generation in the thymus, and its expression in IELps was induced by thymic TCR signaling in an ERK-dependent manner. As a result of Bcl6 deficiency, the precursors of IELps among CD4+CD8+ double-positive thymocytes exhibited increased apoptosis during agonist selection and impaired IELp differentiation and maturation. Together, our results elucidate BCL6 as a crucial transcription factor during the thymic development of CD8αα+ αß IELs.
Subject(s)
Intraepithelial Lymphocytes , Proto-Oncogene Proteins c-bcl-6 , Receptors, Antigen, T-Cell, alpha-beta , Animals , Mice , CD8 Antigens/metabolism , CD8-Positive T-Lymphocytes/metabolism , Intestinal Mucosa , Intraepithelial Lymphocytes/metabolism , Mice, Knockout , Receptors, Antigen, T-Cell, alpha-beta/genetics , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Proto-Oncogene Proteins c-bcl-6/metabolismABSTRACT
Chemotherapy and radiotherapy frequently lead to intestinal damage. The mechanisms governing the repair or regeneration of intestinal damage are still not fully elucidated. Intraepithelial lymphocytes (IELs) are the primary immune cells residing in the intestinal epithelial layer. However, whether IELs are involved in intestinal epithelial injury repair remains unclear. Here, we found that IELs rapidly infiltrated the intestinal crypt region and are crucial for the recovery of the intestinal epithelium post-chemotherapy. Interestingly, IELs predominantly promoted intestinal regeneration by modulating the proliferation of transit-amplifying (TA) cells. Mechanistically, the expression of CD160 on IELs allows for interaction with herpes virus entry mediator (HVEM) on the intestinal epithelium, thereby activating downstream nuclear factor kappa (NF-κB) signaling and further promoting intestinal regeneration. Deficiency in either CD160 or HVEM resulted in reduced proliferation of intestinal progenitor cells, impaired intestinal damage repair, and increased mortality following chemotherapy. Remarkably, the adoptive transfer of CD160-sufficient IELs rescued the Rag1 deficient mice from chemotherapy-induced intestinal inflammation. Overall, our study underscores the critical role of IELs in intestinal regeneration and highlights the potential applications of targeting the CD160-HVEM axis for managing intestinal adverse events post-chemotherapy and radiotherapy.
Subject(s)
Intraepithelial Lymphocytes , Receptors, Immunologic , Animals , Mice , Receptors, Immunologic/metabolism , Intraepithelial Lymphocytes/metabolism , Signal Transduction , Intestines , Intestinal Mucosa/metabolism , RegenerationABSTRACT
BACKGROUND AND AIMS: We aimed to investigate the immune characteristics of intestinal CD8+ gamma delta T (CD8+ γδ T) cells in Crohn's disease (CD) and their correlation with disease activity. METHODS: The study cohorts included 21 CD patients and 21 healthy individuals. CD8+ γδ T cells were isolated from human ileal mucosa for detection by flow cytometry. The activation or inhibition status of cells was detected by detecting the expression of activation marker HLA-DR and the immunosuppressive molecule PD-1 on cells. The cytotoxicity of cells was assessed by detecting the expression of cytotoxic molecules (Perforin, Granzyme B, and TRAIL) in cells. Ratios of investigated cells were calculated as prediction factors by receiver operating characteristic curve (ROC) analysis. RESULTS: The study revealed a reduction in intestinal CD8+ γδT cells among active CD patients, with a more pronounced reduction observed in moderately active patients compared to mildly active patients. Moreover, active CD patients exhibited heightened activation levels in their intestinal CD8+ γδT cells, whereas the activation was comparatively weakened in moderately active patients compared with mildly active patients. Additionally, the cytotoxicity of intestinal CD8+ γδT cells was enhanced solely in mildly active patients, while it was impaired in moderately active patients compared with mildly active patients. Furthermore, HLA-DR+ CD8+ γδT cell ratio, CD8+ γδT ratio, and CD8+ γδT count were identified as indicators in the diagnosis of active CD. Meanwhile, the ratios of Granzyme B+ CD8+ γδT cell and Perforin+ CD8+ γδT cell were identified as indicators that distinguish mildly moderately active CD cases. CONCLUSIONS: Intestinal CD8+ γδT was reduced in active CD patients, but their activation and cytotoxicity were enhanced. However, with increased disease activity, intestinal CD8+ γδ T cells became dysfunctional. CD-specific perturbations observed in various phenotypic markers in CD8+ γδ T cells can be used as indicators to assist in diagnosing CD patients.
Subject(s)
Crohn Disease , Intraepithelial Lymphocytes , Humans , Granzymes , Intraepithelial Lymphocytes/metabolism , Perforin , T-Lymphocytes, Cytotoxic , Intestinal Mucosa , HLA-DR Antigens , Receptors, Antigen, T-Cell, gamma-delta/metabolismABSTRACT
The intestinal epithelium, which segregates the highly stimulatory lumen from the underlying tissue, harbors one of the largest lymphocyte populations in the body, intestinal intraepithelial lymphocytes (IELs). IELs must balance tolerance, resistance, and tissue protection to maintain epithelial homeostasis and barrier integrity. This review discusses the ontogeny, environmental imprinting, T cell receptor (TCR) repertoire, and function of intestinal IELs. Despite distinct developmental pathways, IEL subsets share core traits including an epithelium-adapted profile, innate-like properties, cytotoxic potential, and limited TCR diversity. IELs also receive important developmental and functional cues through interactions with epithelial cells, microbiota, and dietary components. The restricted TCR diversity of IELs suggests that a limited set of intestinal antigens drives IEL responses, with potential functional consequences. Finally, IELs play a key role in promoting homeostatic immunity and epithelial barrier integrity but can become pathogenic upon dysregulation. Therefore, IELs represent intriguing but underexamined therapeutic targets for inflammatory diseases and cancer.
Subject(s)
Intestinal Mucosa , Intraepithelial Lymphocytes , Humans , Animals , Intraepithelial Lymphocytes/immunology , Intraepithelial Lymphocytes/metabolism , Intestinal Mucosa/immunology , Intestinal Mucosa/metabolism , Homeostasis , Receptors, Antigen, T-Cell/metabolism , Intestines/immunologyABSTRACT
OBJECTIVE: Mucosal T cells play a major role in inflammatory bowel disease (IBD). However, their immunometabolism during intestinal inflammation is poorly understood. Due to its impact on cellular metabolism and proinflammatory immune cell function, we here focus on the enzyme ATP citrate lyase (ACLY) in mucosal T cell immunometabolism and its relevance for IBD. DESIGN: ACLY expression and its immunometabolic impact on colitogenic T cell function were analysed in mucosal T cells from patients with IBD and in two experimental colitis models. RESULTS: ACLY was markedly expressed in colon tissue under steady-state conditions but was significantly downregulated in lamina propria mononuclear cells in experimental dextran sodium sulfate-induced colitis and in CD4+ and to a lesser extent in CD8+ T cells infiltrating the inflamed gut in patients with IBD. ACLY-deficient CD4+ T cells showed an impaired capacity to induce intestinal inflammation in a transfer colitis model as compared with wild-type T cells. Assessment of T cell immunometabolism revealed that ACLY deficiency dampened the production of IBD-relevant cytokines and impaired glycolytic ATP production but enriched metabolites involved in the biosynthesis of phospholipids and phosphatidylcholine. Interestingly, the short-chain fatty acid butyrate was identified as a potent suppressor of ACLY expression in T cells, while IL-36α and resolvin E1 induced ACLY levels. In a translational approach, in vivo administration of the butyrate prodrug tributyrin downregulated mucosal infiltration of ACLYhigh CD4+ T cells and ameliorated chronic colitis. CONCLUSION: ACLY controls mucosal T cell immunometabolism and experimental colitis. Therapeutic modulation of ACLY expression in T cells emerges as a novel strategy to promote the resolution of intestinal inflammation.
Subject(s)
Colitis , Inflammatory Bowel Diseases , Intraepithelial Lymphocytes , Humans , Animals , Intraepithelial Lymphocytes/metabolism , ATP Citrate (pro-S)-Lyase/metabolism , CD8-Positive T-Lymphocytes/metabolism , Colitis/metabolism , Inflammation/metabolism , Butyrates , Intestinal Mucosa/metabolism , Dextran Sulfate , Disease Models, AnimalABSTRACT
Our previous study indicated that cytotoxicity of intraepithelial lymphocytes is a poor prognostic factor in feline intestinal T-cell lymphoma (FITL), but the effect of cytotoxic lymphocytes on mucosal epithelium is still unknown. Thus, we investigated the association between cytotoxic lymphocytes and mucosal epithelium in 71 cases of feline intestinal T-cell lymphoma (FITL): epithelial injury, basement membrane injury, cleaved-caspase-3 positivity of epithelial cells, and the number and Ki67 positivity of intraepithelial lymphocytes in granzyme B (GRB)+ and GRB- FITLs were evaluated. Epithelial injury score and the number of intraepithelial lymphocytes in granzyme B (GRB)+ FITL were significantly higher than those of GRB- FITL (P<0.05, P<0.05), but no significant differences were found in the basement membrane injury score, the percentage of cleaved-caspase-3+ epithelial cells, and the percentage of Ki67+ intraepithelial lymphocytes. There was a significant correlation between the epithelial injury score and the number of intraepithelial lymphocytes (P<0.05), but no significant correlation was observed between the epithelial injury score and Ki67+ percentage of intraepithelial lymphocytes. Because epithelial cell cleaved-caspase-3 positivity was observed in FITL, regardless of GRB expression in lymphocytes, GRB-mediated apoptosis may not contribute to epithelial injury in FITL. The association between increased number of intraepithelial lymphocytes and epithelial injury suggests that intraepithelial lymphocytes infiltration may contribute to epithelial injury in FITL.
Subject(s)
Cat Diseases , Intraepithelial Lymphocytes , Lymphoma, T-Cell , Cats , Animals , Granzymes/metabolism , Caspase 3 , Intraepithelial Lymphocytes/metabolism , Ki-67 Antigen , Lymphoma, T-Cell/veterinaryABSTRACT
Intestinal intraepithelial lymphocytes (IELs) exhibit prompt innate-like responses to microenvironmental cues and require strict control of effector functions. Here we showed that Aiolos, an Ikaros zinc-finger family member encoded by Ikzf3, acted as a regulator of IEL activation. Ikzf3-/- CD8αα+ IELs had elevated expression of NK receptors, cytotoxic enzymes, cytokines and chemokines. Single-cell RNA sequencing of Ikzf3-/- and Ikzf3+/+ IELs showed an amplified effector machinery in Ikzf3-/- CD8αα+ IELs compared to Ikzf3+/+ counterparts. Ikzf3-/- CD8αα+ IELs had increased responsiveness to interleukin-15, which explained a substantial part, but not all, of the observed phenotypes. Aiolos binding sites were close to those for the transcription factors STAT5 and RUNX, which promote interleukin-15 signaling and cytolytic programs, and Ikzf3 deficiency partially increased chromatin accessibility and histone acetylation in these regions. Ikzf3 deficiency in mice enhanced susceptibility to colitis, underscoring the relevance of Aiolos in regulating the effector function in IELs.