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Zhang X, Zhu B, Li L, Xu J, Han Y, Zhang J, Hua Z. The dephosphorylation of FADD at S191 induces an excessive expansion of TCRαβ + IELs in the intestinal mucosa. Immunology 2022; 167:233-246. [PMID: 35753028 DOI: 10.1111/imm.13533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 05/19/2022] [Indexed: 06/15/2023] Open
Abstract
Intestinal intraepithelial lymphocytes (IELs) play a crucial role in host defence against pathogens in the intestinal mucosa. The development of intestinal IELs is distinct from peripheral T lymphocytes and remains elusive. Fas-associated protein with death domain (FADD) is important for T cell development in the thymus. Here we describe a novel function of FADD in the IEL development. FADD (S191A), a mouse FADD mutant at Ser191 to Ala mimicking constitutively unphosphorylated FADD, promoted a rapid expansion of TCRαβ+ IELs, not TCRγδ+ IELs. Mechanism investigation indicated that the dephosphorylation of FADD was required for cell activation mainly in TCRαβ+ CD8+ T cells. Consistently, FADD (S191A) as dephosphorylated FADD led to a high NF-κB activation in the TCR-dependent cell expansion. In addition, The FADD (S191A)-induced abnormal IEL populations resulted in the increased incidence and severity of colitis in mice. In summary, FADD signalling is involved in the intestinal IEL development and might be a regulator for intestinal mucosal homeostasis.
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Affiliation(s)
- Xuerui Zhang
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
- School of Pharmaceutical Sciences, Shandong First Medical University, Taian, China
| | - Banghui Zhu
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Lin Li
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Jiahong Xu
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Yuheng Han
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Jing Zhang
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Zichun Hua
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
- School of Biopharmacy, China Pharmaceutical University, Nanjing, China
- Changzhou High-Tech Research Institute of Nanjing University and Jiangsu Target Pharma Laboratories Inc., Changzhou, China
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Hue SSS, Ng SB, Wang S, Tan SY. Cellular Origins and Pathogenesis of Gastrointestinal NK- and T-Cell Lymphoproliferative Disorders. Cancers (Basel) 2022; 14:2483. [PMID: 35626087 PMCID: PMC9139583 DOI: 10.3390/cancers14102483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 05/08/2022] [Accepted: 05/13/2022] [Indexed: 11/25/2022] Open
Abstract
The intestinal immune system, which must ensure appropriate immune responses to both pathogens and commensal microflora, comprises innate lymphoid cells and various T-cell subsets, including intra-epithelial lymphocytes (IELs). An example of innate lymphoid cells is natural killer cells, which may be classified into tissue-resident, CD56bright NK-cells that serve a regulatory function and more mature, circulating CD56dim NK-cells with effector cytolytic properties. CD56bright NK-cells in the gastrointestinal tract give rise to indolent NK-cell enteropathy and lymphomatoid gastropathy, as well as the aggressive extranodal NK/T cell lymphoma, the latter following activation by EBV infection and neoplastic transformation. Conventional CD4+ TCRαβ+ and CD8αβ+ TCRαβ+ T-cells are located in the lamina propria and the intraepithelial compartment of intestinal mucosa as type 'a' IELs. They are the putative cells of origin for CD4+ and CD8+ indolent T-cell lymphoproliferative disorders of the gastrointestinal tract and intestinal T-cell lymphoma, NOS. In addition to such conventional T-cells, there are non-conventional T-cells in the intra-epithelial compartment that express CD8αα and innate lymphoid cells that lack TCRs. The central feature of type 'b' IELs is the expression of CD8αα homodimers, seen in monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), which primarily arises from both CD8αα+ TCRαβ+ and CD8αα+ TCRγδ+ IELs. EATL is the other epitheliotropic T-cell lymphoma in the GI tract, a subset of which arises from the expansion and reprograming of intracytoplasmic CD3+ innate lymphoid cells, driven by IL15 and mutations of the JAK-STAT pathway.
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Affiliation(s)
- Susan Swee-Shan Hue
- Department of Pathology, National University Hospital, Singapore 119074, Singapore; (S.S.-S.H.); (S.W.)
| | - Siok-Bian Ng
- Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119074, Singapore;
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Shi Wang
- Department of Pathology, National University Hospital, Singapore 119074, Singapore; (S.S.-S.H.); (S.W.)
| | - Soo-Yong Tan
- Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119074, Singapore;
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Zhang YY, Lin YT, Wang L, Sun XW, Dang EL, Xue K, Zhang WG, Zhang KM, Wang G, Li B. CD8αα +T cells exert a pro-inflammatory role in patients with psoriasis. SKIN HEALTH AND DISEASE 2021; 1:e64. [PMID: 35663772 PMCID: PMC9060015 DOI: 10.1002/ski2.64] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 08/05/2021] [Accepted: 08/05/2021] [Indexed: 11/29/2022]
Abstract
Background Psoriasis is a common chronic inflammatory disease caused by excessive activation of CD4+T cells, including Th17, Th1 and Th22. The role of CD8+T cells in psoriasis pathogenesis remains poorly understood. Aim To identify the phenotype of CD8+T cells in patients with psoriasis and to investigate its role in the formation of lesions. Methods The phenotype of CD8+T cells in psoriatic lesions was detected by immunofluorescence staining. Flow cytometry was performed to detect their phenotype in peripheral blood. Thereafter, coculture of CD8αα+T cells with autogenous CD4+T cells was performed to investigate the function of CD8αα+T cells in patients with psoriasis. Finally, pro‐inflammatory factors produced by CD8αα+T cells were examined by immunofluorescence staining and flow cytometry. Results Compared to the CD8αβ+T cells, CD8αα+T cell infiltration in psoriatic lesions markedly increased. Moreover, epidermal CD8αα+T cells exhibited tissue‐resident memory T cells (TRM) phenotypes and dermal CD8αα+T cells exhibited effector memory (TEM) phenotypes in psoriatic lesions. Additionally, we found that CD8αα+T cells from patients with psoriasis did not express the markers of regulatory T cells and could promote the proliferation of CD4+T effector cells and produce interleukin‐17 and interferon‐γ. Conclusions Our findings demonstrate that CD8αα+T cells contribute to the pathogenesis of psoriasis by producing pro‐inflammatory factors.
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Affiliation(s)
- Y Y Zhang
- Department of Dermatology Xijing Hospital Fourth Military Medical University Xi'an China
| | - Y T Lin
- Department of Dermatology Xijing Hospital Fourth Military Medical University Xi'an China
| | - L Wang
- Department of Dermatology Xijing Hospital Fourth Military Medical University Xi'an China
| | - X W Sun
- Department of Dermatology Xijing Hospital Fourth Military Medical University Xi'an China
| | - E L Dang
- Department of Dermatology Xijing Hospital Fourth Military Medical University Xi'an China
| | - K Xue
- Department of Dermatology Xijing Hospital Fourth Military Medical University Xi'an China
| | - W G Zhang
- Department of Dermatology Xijing Hospital Fourth Military Medical University Xi'an China
| | - K M Zhang
- Institute of Dermatology Taiyuan City Central Hospital Shanxi Key Laboratory for Immunological Dermatosis Taiyuan China
| | - G Wang
- Department of Dermatology Xijing Hospital Fourth Military Medical University Xi'an China
| | - B Li
- Department of Dermatology Xijing Hospital Fourth Military Medical University Xi'an China
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4
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Mölzer C, Heissigerova J, Wilson HM, Kuffova L, Forrester JV. Immune Privilege: The Microbiome and Uveitis. Front Immunol 2021; 11:608377. [PMID: 33569055 PMCID: PMC7868421 DOI: 10.3389/fimmu.2020.608377] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 12/04/2020] [Indexed: 02/03/2023] Open
Abstract
Immune privilege (IP), a term introduced to explain the unpredicted acceptance of allogeneic grafts by the eye and the brain, is considered a unique property of these tissues. However, immune responses are modified by the tissue in which they occur, most of which possess IP to some degree. The eye therefore displays a spectrum of IP because it comprises several tissues. IP as originally conceived can only apply to the retina as it contains few tissue-resident bone-marrow derived myeloid cells and is immunologically shielded by a sophisticated barrier – an inner vascular and an outer epithelial barrier at the retinal pigment epithelium. The vascular barrier comprises the vascular endothelium and the glia limitans. Immune cells do not cross the blood-retinal barrier (BRB) despite two-way transport of interstitial fluid, governed by tissue oncotic pressure. The BRB, and the blood-brain barrier (BBB) mature in the neonatal period under signals from the expanding microbiome and by 18 months are fully established. However, the adult eye is susceptible to intraocular inflammation (uveitis; frequency ~200/100,000 population). Uveitis involving the retinal parenchyma (posterior uveitis, PU) breaches IP, while IP is essentially irrelevant in inflammation involving the ocular chambers, uveal tract and ocular coats (anterior/intermediate uveitis/sclerouveitis, AU). Infections cause ~50% cases of AU and PU but infection may also underlie the pathogenesis of immune-mediated “non-infectious” uveitis. Dysbiosis accompanies the commonest form, HLA-B27–associated AU, while latent infections underlie BRB breakdown in PU. This review considers the pathogenesis of uveitis in the context of IP, infection, environment, and the microbiome.
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Affiliation(s)
- Christine Mölzer
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Jarmila Heissigerova
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czechia
| | - Heather M Wilson
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Lucia Kuffova
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom.,Eye Clinic, Aberdeen Royal Infirmary, Aberdeen, United Kingdom
| | - John V Forrester
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
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Lebel MÈ, Coutelier M, Galipeau M, Kleinman CL, Moon JJ, Melichar HJ. Differential expression of tissue-restricted antigens among mTEC is associated with distinct autoreactive T cell fates. Nat Commun 2020; 11:3734. [PMID: 32709894 PMCID: PMC7381629 DOI: 10.1038/s41467-020-17544-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 07/07/2020] [Indexed: 12/12/2022] Open
Abstract
Medullary thymic epithelial cells (mTEC) contribute to the development of T cell tolerance by expressing and presenting tissue-restricted antigens (TRA), so that developing T cells can assess the self-reactivity of their antigen receptors prior to leaving the thymus. mTEC are a heterogeneous population of cells that differentially express TRA. Whether mTEC subsets induce distinct autoreactive T cell fates remains unclear. Here, we establish bacterial artificial chromosome (BAC)-transgenic mouse lines with biased mTEClo or mTEChi expression of model antigens. The transgenic lines support negative selection of antigen-specific thymocytes depending on antigen dose. However, model antigen expression predominantly by mTEClo supports TCRαβ+ CD8αα intraepithelial lymphocyte development; meanwhile, mTEChi-restricted expression preferentially induces Treg differentiation of antigen-specific cells in these models to impact control of infectious agents and tumor growth. In summary, our data suggest that mTEC subsets may have a function in directing distinct mechanisms of T cell tolerance.
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Affiliation(s)
- Marie-Ève Lebel
- Maisonneuve-Rosemont Hospital Research Center, 5415 Boulevard de l'Assomption, Montreal, QC, H1T 2M4, Canada
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, C.P. 6128, succ. Centre-ville, Montreal, QC, H3C 3J7, Canada
| | - Marie Coutelier
- The Lady Davis Institute for Medical Research, Jewish General Hospital, 3999 Côte Ste-Catherine Road Room E-542, Montreal, QC, H3T 1E2, Canada
- Department of Human Genetics, McGill University, Rm W-315, Strathcona Anatomy & Dentistry Building 3640 rue University, Montreal, QC, H3A 0C7, Canada
| | - Maria Galipeau
- Maisonneuve-Rosemont Hospital Research Center, 5415 Boulevard de l'Assomption, Montreal, QC, H1T 2M4, Canada
| | - Claudia L Kleinman
- The Lady Davis Institute for Medical Research, Jewish General Hospital, 3999 Côte Ste-Catherine Road Room E-542, Montreal, QC, H3T 1E2, Canada
- Department of Human Genetics, McGill University, Rm W-315, Strathcona Anatomy & Dentistry Building 3640 rue University, Montreal, QC, H3A 0C7, Canada
| | - James J Moon
- Center for Immunology and Inflammatory Diseases and Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital and Harvard Medical School, 149 13th Street, Charlestown, MA, 02129, USA
| | - Heather J Melichar
- Maisonneuve-Rosemont Hospital Research Center, 5415 Boulevard de l'Assomption, Montreal, QC, H1T 2M4, Canada.
- Département de médecine, Université de Montréal, C.P. 6128, succ. Centre-ville, Montreal, QC, H3C 3J7, Canada.
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Ma H, Qiu Y, Yang H. Intestinal intraepithelial lymphocytes: Maintainers of intestinal immune tolerance and regulators of intestinal immunity. J Leukoc Biol 2020; 109:339-347. [PMID: 32678936 PMCID: PMC7891415 DOI: 10.1002/jlb.3ru0220-111] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 04/20/2020] [Indexed: 12/19/2022] Open
Abstract
Intestinal immune tolerance is essential for the immune system, as it prevents abnormal immune responses to large quantities of antigens from the intestinal lumen, such as antigens from commensal microorganisms, and avoids self‐injury. Intestinal intraepithelial lymphocytes (IELs), a special group of mucosal T lymphocytes, play a significant role in intestinal immune tolerance. To accomplish this, IELs exhibit a high threshold of activation and low reactivity to most antigens from the intestinal lumen. In particular, CD8αα+TCRαβ+ IELs, TCRγδ+ IELs, and CD4+CD8αα+ IELs show great potential for maintaining intestinal immune tolerance and regulating intestinal immunity. However, if the intestinal microenvironment becomes abnormal or intestinal tolerance is broken, IELs may be activated abnormally and become pathogenic.
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Affiliation(s)
- Haitao Ma
- Department of General Surgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Yuan Qiu
- Department of General Surgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Hua Yang
- Department of General Surgery, Xinqiao Hospital, Army Medical University, Chongqing, China
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7
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Zhou C, Qiu Y, Yang H. CD4CD8αα IELs: They Have Something to Say. Front Immunol 2019; 10:2269. [PMID: 31649659 PMCID: PMC6794356 DOI: 10.3389/fimmu.2019.02269] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 09/09/2019] [Indexed: 12/22/2022] Open
Abstract
The intraepithelial lymphocytes (IELs) that reside within the epithelium of the intestine play a critical role in maintaining the immune balance of the gut. CD4CD8αα IELs are one of the most important types of IELs, and they play an irreplaceable role in maintaining the balance of the intestinal immune system. CD4CD8αα IELs are often regarded as a special subtype of CD4+ IELs that can express CD8αα on their cytomembrane. Hence, CD4CD8αα IELs not only have the ability to modulate the functions of immune cells but also are regarded as cytotoxic T lymphocytes (CTLs). Transcription factors, microbes, and dietary factors have a substantial effect on the development of CD4CD8αα IELs, which make them exert immunosuppression and cytotoxicity activities. In addition, there is an intimate relationship between CD4CD8αα IELs and inflammatory bowel disease (IBD), whereas it is still unclear how CD4CD8αα IELs influence IBD. As such, this review will focus on the unparalleled differentiation of CD4CD8αα IELs and discuss how these cells might be devoted to tolerance and immunopathological responses in the intestinal tract. In addition, the role of CD4CD8αα IELs in IBD would also be discussed.
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Affiliation(s)
- Chao Zhou
- Department of General Surgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Yuan Qiu
- Department of General Surgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Hua Yang
- Department of General Surgery, Xinqiao Hospital, Army Medical University, Chongqing, China
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8
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Foreign antigen-independent memory-phenotype CD4 + T cells: a new player in innate immunity? Nat Rev Immunol 2018; 18:1. [PMID: 29480288 DOI: 10.1038/nri.2018.13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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9
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Statovci D, Aguilera M, MacSharry J, Melgar S. The Impact of Western Diet and Nutrients on the Microbiota and Immune Response at Mucosal Interfaces. Front Immunol 2017; 8:838. [PMID: 28804483 PMCID: PMC5532387 DOI: 10.3389/fimmu.2017.00838] [Citation(s) in RCA: 280] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 07/03/2017] [Indexed: 12/11/2022] Open
Abstract
Recent findings point toward diet having a major impact on human health. Diets can either affect the gut microbiota resulting in alterations in the host’s physiological responses or by directly targeting the host response. The microbial community in the mammalian gut is a complex and dynamic system crucial for the development and maturation of both systemic and mucosal immune responses. Therefore, the complex interaction between available nutrients, the microbiota, and the immune system are central regulators in maintaining homeostasis and fighting against invading pathogens at mucosal sites. Westernized diet, defined as high dietary intake of saturated fats and sucrose and low intake of fiber, represent a growing health risk contributing to the increased occurrence of metabolic diseases, e.g., diabetes and obesity in countries adapting a westernized lifestyle. Inflammatory bowel diseases (IBD) and asthma are chronic mucosal inflammatory conditions of unknown etiology with increasing prevalence worldwide. These conditions have a multifactorial etiology including genetic factors, environmental factors, and dysregulated immune responses. Their increased prevalence cannot solely be attributed to genetic considerations implying that other factors such as diet can be a major contributor. Recent reports indicate that the gut microbiota and modifications thereof, due to a consumption of a diet high in saturated fats and low in fibers, can trigger factors regulating the development and/or progression of both conditions. While asthma is a disease of the airways, increasing evidence indicates a link between the gut and airways in disease development. Herein, we provide a comprehensive review on the impact of westernized diet and associated nutrients on immune cell responses and the microbiota and how these can influence the pathology of IBD and asthma.
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Affiliation(s)
- Donjete Statovci
- APC Microbiome Institute, University College Cork, Cork, Ireland
| | - Mònica Aguilera
- APC Microbiome Institute, University College Cork, Cork, Ireland
| | - John MacSharry
- APC Microbiome Institute, University College Cork, Cork, Ireland.,School of Microbiology, University College Cork, Cork, Ireland
| | - Silvia Melgar
- APC Microbiome Institute, University College Cork, Cork, Ireland
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White JT, Cross EW, Kedl RM. Antigen-inexperienced memory CD8 + T cells: where they come from and why we need them. Nat Rev Immunol 2017; 17:391-400. [PMID: 28480897 DOI: 10.1038/nri.2017.34] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Memory-phenotype CD8+ T cells exist in substantial numbers within hosts that have not been exposed to either foreign antigen or overt lymphopenia. These antigen-inexperienced memory-phenotype T cells can be divided into two major subsets: 'innate memory' T cells and 'virtual memory' T cells. Although these two subsets are nearly indistinguishable by surface markers alone, notable developmental and functional differences exist between the two subsets, which suggests that they represent distinct populations. In this Opinion article, we review the available literature on each subset, highlighting the key differences between these populations. Furthermore, we suggest a unifying model for the categorization of antigen-inexperienced memory-phenotype CD8+ T cells.
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Affiliation(s)
- Jason T White
- Department of Microbiology and Immunology, The Peter Doherty Institute, University of Melbourne, 792 Elizabeth Street, Melbourne, Victoria 3000, Australia
| | - Eric W Cross
- Department of Immunology and Microbiology, University of Colorado Denver at Anschutz Medical Campus, School of Medicine, Mail Stop 8333, Room P18-8115, 12800 East 19th Avenue, Aurora, Colorado 80045-2537, USA
| | - Ross M Kedl
- Department of Immunology and Microbiology, University of Colorado Denver at Anschutz Medical Campus, School of Medicine, Mail Stop 8333, Room P18-8115, 12800 East 19th Avenue, Aurora, Colorado 80045-2537, USA
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Hickey MJ, Chow Z. Viewing immune regulation as it happens: in vivo imaging for investigation of regulatory T-cell function. Immunol Cell Biol 2017; 95:514-519. [PMID: 28420873 DOI: 10.1038/icb.2017.33] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 04/10/2017] [Accepted: 04/10/2017] [Indexed: 12/12/2022]
Abstract
Regulatory T cells (Tregs) play indispensable roles in the immune system, in limiting excessive or inappropriate immune and inflammatory responses. They achieve this function via effects on other immune cells in the secondary lymphoid system, and in peripheral locations such as skin, gut and bone marrow. As for the more extensively studied cellular players in the immune system, particularly dendritic cells and conventional T cells, in vivo imaging of Tregs via two-photon (or multiphoton) microscopy (MPM) has been central to the development of understanding how these cells function. In this brief review, we will describe the studies that have utilised MPM to examine Treg behaviour in vivo. These studies have investigated Treg behaviour in lymph nodes and spleen, as well as in peripheral organs such as skin, small intestine and bone marrow. The findings from these experiments underline how assumptions made about Treg function based on results of in vitro experiments are often not supported by direct visualisation of these cells in their normal in vivo settings. Together this work reveals that only via MPM analysis can Treg function be investigated in the complicated multicellular environments where conventional T cells, antigen-presenting cells and other potential cellular targets of Tregs are present with each undergoing their own specific actions.
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Affiliation(s)
- Michael J Hickey
- Centre for Inflammatory Diseases, Department of Medicine, Monash University, Monash Medical Centre, Clayton, Victoria, Australia
| | - Zachary Chow
- Centre for Inflammatory Diseases, Department of Medicine, Monash University, Monash Medical Centre, Clayton, Victoria, Australia
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Chen W, Pu A, Sheng B, Zhang Z, Li L, Liu Z, Wang Q, Li X, Ma Y, Yu M, Sun L, Qiu Y, Yang H. Aryl hydrocarbon receptor activation modulates CD8αα+TCRαβ+ IELs and suppression of colitis manifestations in mice. Biomed Pharmacother 2017; 87:127-134. [DOI: 10.1016/j.biopha.2016.12.061] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 12/10/2016] [Accepted: 12/14/2016] [Indexed: 01/23/2023] Open
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13
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TLR2-Dependent Signaling for IL-15 Production Is Essential for the Homeostasis of Intestinal Intraepithelial Lymphocytes. Mediators Inflamm 2016; 2016:4281865. [PMID: 27563173 PMCID: PMC4983668 DOI: 10.1155/2016/4281865] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 06/01/2016] [Accepted: 06/06/2016] [Indexed: 12/28/2022] Open
Abstract
TLR2 signaling is related to colitis and involved in regulation of innate immunity in the intestinal tract, but the mechanisms remain unclear. The aim of this study is to investigate how TLR2 affects differentiation of intraepithelial lymphocytes (IELs) and regulates the susceptibility of colitis. IELs were isolated from the small intestine and colon of mice, respectively. The IEL phenotype, activation, and apoptosis were examined using flow cytometry and RT-PCR. IL-15 expression and IEL location were detected through immunohistochemistry. The experimental colitis was induced by administration of dextran sulfate sodium (DSS). We found that the numbers of CD8αα+, CD8αβ+, and TCRγδ+ IELs were significantly decreased in TLR2-deficient mice and the residual IELs displayed reduced activation and proliferation and increased apoptosis, accompanied with impaired IL-15 expression by intestinal epithelial cells (IECs). Further study showed that TLR2 signaling maintained the expression of IL-15 in IEC via NF-κB activation. Moreover, TLR2-deficient mice were found to be more susceptible to DSS-induced colitis as shown by the increased severity of colitis. Our results demonstrate that IECs contribute to the maintenance of IELs at least partly via TLR2-dependent IL-15 production, which provides a clue that may link IECs to innate immune protection of the host via IELs.
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