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Shirafkan F, Hensel L, Rattay K. Immune tolerance and the prevention of autoimmune diseases essentially depend on thymic tissue homeostasis. Front Immunol 2024; 15:1339714. [PMID: 38571951 PMCID: PMC10987875 DOI: 10.3389/fimmu.2024.1339714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 03/11/2024] [Indexed: 04/05/2024] Open
Abstract
The intricate balance of immune reactions towards invading pathogens and immune tolerance towards self is pivotal in preventing autoimmune diseases, with the thymus playing a central role in establishing and maintaining this equilibrium. The induction of central immune tolerance in the thymus involves the elimination of self-reactive T cells, a mechanism essential for averting autoimmunity. Disruption of the thymic T cell selection mechanisms can lead to the development of autoimmune diseases. In the dynamic microenvironment of the thymus, T cell migration and interactions with thymic stromal cells are critical for the selection processes that ensure self-tolerance. Thymic epithelial cells are particularly significant in this context, presenting self-antigens and inducing the negative selection of autoreactive T cells. Further, the synergistic roles of thymic fibroblasts, B cells, and dendritic cells in antigen presentation, selection and the development of regulatory T cells are pivotal in maintaining immune responses tightly regulated. This review article collates these insights, offering a comprehensive examination of the multifaceted role of thymic tissue homeostasis in the establishment of immune tolerance and its implications in the prevention of autoimmune diseases. Additionally, the developmental pathways of the thymus are explored, highlighting how genetic aberrations can disrupt thymic architecture and function, leading to autoimmune conditions. The impact of infections on immune tolerance is another critical area, with pathogens potentially triggering autoimmunity by altering thymic homeostasis. Overall, this review underscores the integral role of thymic tissue homeostasis in the prevention of autoimmune diseases, discussing insights into potential therapeutic strategies and examining putative avenues for future research on developing thymic-based therapies in treating and preventing autoimmune conditions.
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2
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This S, Rogers D, Mallet Gauthier È, Mandl JN, Melichar HJ. What's self got to do with it: Sources of heterogeneity among naive T cells. Semin Immunol 2023; 65:101702. [PMID: 36463711 DOI: 10.1016/j.smim.2022.101702] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 11/23/2022] [Accepted: 11/25/2022] [Indexed: 12/04/2022]
Abstract
There is a long-standing assumption that naive CD4+ and CD8+ T cells are largely homogeneous populations despite the extraordinary diversity of their T cell receptors (TCR). The self-immunopeptidome plays a key role in the selection of the naive T cell repertoire in the thymus, and self-peptides are also an important driver of differences between individual naive T cells with regard to their subsequent functional contributions to an immune response. Accumulating evidence suggests that as early as the β-selection stage of T cell development, when only one of the recombined chains of the mature TCR is expressed, signaling thresholds may be established for positive selection of immature thymocytes. Stochastic encounters subsequently made with self-ligands during positive selection in the thymus imprint functional biases that a T cell will carry with it throughout its lifetime, although ongoing interactions with self in the periphery ensure a level of plasticity in the gene expression wiring of naive T cells. Identifying the sources of heterogeneity in the naive T cell population and which functional attributes of T cells can be modulated through post-thymic interventions versus those that are fixed during T cell development, could enable us to better select or generate T cells with particular traits to improve the efficacy of T cell therapies.
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Affiliation(s)
- Sébastien This
- Department of Microbiology, Infectious Disease, and Immunology, Université de Montréal, Montreal, Canada; Immunology-Oncology Unit, Maisonneuve-Rosemont Hospital Research Center, Montreal, Canada
| | - Dakota Rogers
- Department of Physiology and McGill Research Centre on Complex Traits, McGill University, Montreal, Canada
| | - Ève Mallet Gauthier
- Department of Microbiology, Infectious Disease, and Immunology, Université de Montréal, Montreal, Canada; Immunology-Oncology Unit, Maisonneuve-Rosemont Hospital Research Center, Montreal, Canada
| | - Judith N Mandl
- Department of Physiology and McGill Research Centre on Complex Traits, McGill University, Montreal, Canada.
| | - Heather J Melichar
- Immunology-Oncology Unit, Maisonneuve-Rosemont Hospital Research Center, Montreal, Canada; Department of Medicine, Université de Montréal, Montreal, Canada.
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3
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Regulation of T-cell Receptor Gene Expression by Three-Dimensional Locus Conformation and Enhancer Function. Int J Mol Sci 2020; 21:ijms21228478. [PMID: 33187197 PMCID: PMC7696796 DOI: 10.3390/ijms21228478] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 10/29/2020] [Accepted: 11/04/2020] [Indexed: 11/16/2022] Open
Abstract
The adaptive immune response in vertebrates depends on the expression of antigen-specific receptors in lymphocytes. T-cell receptor (TCR) gene expression is exquisitely regulated during thymocyte development to drive the generation of αβ and γδ T lymphocytes. The TCRα, TCRβ, TCRγ, and TCRδ genes exist in two different configurations, unrearranged and rearranged. A correctly rearranged configuration is required for expression of a functional TCR chain. TCRs can take the form of one of three possible heterodimers, pre-TCR, TCRαβ, or TCRγδ which drive thymocyte maturation into αβ or γδ T lymphocytes. To pass from an unrearranged to a rearranged configuration, global and local three dimensional (3D) chromatin changes must occur during thymocyte development to regulate gene segment accessibility for V(D)J recombination. During this process, enhancers play a critical role by modifying the chromatin conformation and triggering noncoding germline transcription that promotes the recruitment of the recombination machinery. The different signaling that thymocytes receive during their development controls enhancer activity. Here, we summarize the dynamics of long-distance interactions established through chromatin regulatory elements that drive transcription and V(D)J recombination and how different signaling pathways are orchestrated to regulate the activity of enhancers to precisely control TCR gene expression during T-cell maturation.
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Li B, Li Y, Li K, Zhu L, Yu Q, Cai P, Fang J, Zhang W, Du P, Jiang C, Lin J, Qu K. APEC: an accesson-based method for single-cell chromatin accessibility analysis. Genome Biol 2020; 21:116. [PMID: 32398051 PMCID: PMC7218568 DOI: 10.1186/s13059-020-02034-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 04/30/2020] [Indexed: 12/21/2022] Open
Abstract
The development of sequencing technologies has promoted the survey of genome-wide chromatin accessibility at single-cell resolution. However, comprehensive analysis of single-cell epigenomic profiles remains a challenge. Here, we introduce an accessibility pattern-based epigenomic clustering (APEC) method, which classifies each cell by groups of accessible regions with synergistic signal patterns termed “accessons”. This python-based package greatly improves the accuracy of unsupervised single-cell clustering for many public datasets. It also predicts gene expression, identifies enriched motifs, discovers super-enhancers, and projects pseudotime trajectories. APEC is available at https://github.com/QuKunLab/APEC.
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Affiliation(s)
- Bin Li
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, 230001, Anhui, China
| | - Young Li
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, 230001, Anhui, China
| | - Kun Li
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, 230001, Anhui, China
| | - Lianbang Zhu
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, 230001, Anhui, China
| | - Qiaoni Yu
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, 230001, Anhui, China
| | - Pengfei Cai
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, 230001, Anhui, China
| | - Jingwen Fang
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, 230001, Anhui, China.,HanGene Biotech, Xiaoshan Innovation Polis, Hangzhou, 310000, Zhejiang, China
| | - Wen Zhang
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, 230001, Anhui, China
| | - Pengcheng Du
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, 230001, Anhui, China
| | - Chen Jiang
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, 230001, Anhui, China
| | - Jun Lin
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, 230001, Anhui, China
| | - Kun Qu
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, 230001, Anhui, China. .,CAS Center for Excellence in Molecular Cell Sciences, The CAS Key Laboratory of Innate Immunity and Chronic Disease, University of Science and Technology of China, Hefei, 230027, Anhui, China.
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5
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Nacka-Aleksić M, Pilipović I, Kotur-Stevuljević J, Petrović R, Sopta J, Leposavić G. Sexual dimorphism in rat thymic involution: a correlation with thymic oxidative status and inflammation. Biogerontology 2019; 20:545-569. [DOI: 10.1007/s10522-019-09816-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 05/12/2019] [Indexed: 01/05/2023]
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Leung-Gurung L, Escalante Cobb P, Mourad F, Zambrano C, Muscato Z, Sanchez V, Godde K, Broussard C. Methoxychlor metabolite HPTE alters viability and differentiation of embryonic thymocytes from C57BL/6 mice. J Immunotoxicol 2018; 15:104-118. [PMID: 29973080 DOI: 10.1080/1547691x.2018.1474978] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Endocrine-disrupting chemicals (EDC) are widespread in the built and natural environments. Heightened public awareness of their potential danger has led to concern about whether EDC and their metabolites have significant negative biological effects. Studies have shown that EDC like DDT and other organochlorine pesticides, such as methoxychlor (MXC), have adverse effects on immune cells, but no studies have addressed the impact of HPTE, the primary metabolite of MXC. To elucidate the presence and significance of HPTE adverse effects, this study explored the impact of HPTE on a critical window and component of immune system development, embryonic T-cell development. Lesions at this phase of development can lead to lifelong immune dysfunction and increased incidence of immune disease, such as autoimmunity. Embry-onic thymocytes (GD 16-18) from C57BL/6 mice were subjected to an in vitro differentiation culture that mimicked early steps in thymocyte development in the presence of 0.005, 0.05, 0.5, 5, or 50 μM HPTE, or a model endocrine disruptor, DES. The results indicated that compared to the vehicle control, HPTE- and DES-induced death of thymocytes. Annexin-V staining and Caspase 8, markers of programed cell death, revealed that the loss of cells was due at least in part to induction of apoptosis. Moreover, HPTE-induced cell death not only resulted in selective loss of double positive thymocytes, but also loss of developing CD4 intermediate cells (post-double positive partially differentiated thymocyte population). Phenotypic analysis of thymocyte maturation (T-cell receptor, TCR) and TCR ligation (CD5) surface markers revealed that surviving embryonic thymocytes expressed low levels of both. Taken together these data demonstrate that immature embryonic thymocytes are sensitive to HPTE exposure and that HPTE exposure targets thymocyte populations undergoing critical differentiation steps. These findings suggest HPTE may play a pivotal role in MXC exposure-induced immune dysfunction.
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Affiliation(s)
- Lucie Leung-Gurung
- a School of Community and Global Health , Claremont Graduate University , Claremont , CA , USA
| | | | - Faraj Mourad
- c Irvine Health, University of California , Orange , CA , USA
| | - Cristina Zambrano
- d Department of Pharmacology, School of Medicine , University of California San Diego , La Jolla , CA , USA
| | - Zachary Muscato
- e Department of Psychiatry, School of Medicine , Oregon Health and Science University , Portland , OR , USA
| | - Victoria Sanchez
- b Department of Biology , University of La Verne , La Verne , CA , USA
| | - Kanya Godde
- f Department of Sociology/Anthropology , University of La Verne , La Verne , CA , USA
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7
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Sakata M, Ohigashi I, Takahama Y. Cellularity of Thymic Epithelial Cells in the Postnatal Mouse. THE JOURNAL OF IMMUNOLOGY 2018; 200:1382-1388. [PMID: 29298829 DOI: 10.4049/jimmunol.1701235] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 12/05/2017] [Indexed: 12/13/2022]
Abstract
The molecular and cellular biology of thymic epithelial cells (TECs) often relies on the analysis of TECs isolated in enzymatically digested single-cell suspensions derived from mouse thymus. Many independent studies have reported that the estimated cellularity of total TECs isolated from one adult mouse is on the order of up to 105 However, these numbers appear extremely small given that the cellularity of total thymocytes exceeds 108 and that TECs play multiple roles in thymocyte development and repertoire formation. In the present study, we aimed to measure the numbers of β5t-expressing cortical TECs and Aire-expressing medullary TECs in postnatal mouse thymus in situ without enzymatic digestion. The numbers of these TECs were manually counted in individual thymic sections and were three-dimensionally summed throughout the entire thymic lobes. The results show that the cellularity of total TECs in one 5-wk-old female mouse exceeds 106, containing ∼9 × 105 β5t+ cortical TECs and ∼1.1 × 106 Aire+ medullary TECs. These results suggest that the use of conventional enzymatic digestion methods for the isolation of TECs may have resulted in the underestimation of the cellularity, and possibly the biology, of TECs.
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Affiliation(s)
- Mie Sakata
- Division of Experimental Immunology, Institute of Advanced Medical Sciences, University of Tokushima, Tokushima 770-8503, Japan
| | - Izumi Ohigashi
- Division of Experimental Immunology, Institute of Advanced Medical Sciences, University of Tokushima, Tokushima 770-8503, Japan
| | - Yousuke Takahama
- Division of Experimental Immunology, Institute of Advanced Medical Sciences, University of Tokushima, Tokushima 770-8503, Japan
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8
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Abstract
The peripheral T cell repertoire is sculpted from prototypic T cells in the thymus bearing randomly generated T cell receptors (TCR) and by a series of developmental and selection steps that remove cells that are unresponsive or overly reactive to self-peptide–MHC complexes. The challenge of understanding how the kinetics of T cell development and the statistics of the selection processes combine to provide a diverse but self-tolerant T cell repertoire has invited quantitative modeling approaches, which are reviewed here.
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Affiliation(s)
- Andrew J Yates
- Departments of Systems and Computational Biology, Microbiology and Immunology, Albert Einstein College of Medicine , New York, NY , USA
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9
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Zarnitsyna VI, Evavold BD, Schoettle LN, Blattman JN, Antia R. Estimating the diversity, completeness, and cross-reactivity of the T cell repertoire. Front Immunol 2013; 4:485. [PMID: 24421780 PMCID: PMC3872652 DOI: 10.3389/fimmu.2013.00485] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Accepted: 12/10/2013] [Indexed: 11/13/2022] Open
Abstract
In order to recognize and combat a diverse array of pathogens the immune system has a large repertoire of T cells having unique T cell receptors (TCRs) with only a few clones specific for any given antigen. We discuss how the number of different possible TCRs encoded in the genome (the potential repertoire) and the number of different TCRs present in an individual (the realized repertoire) can be measured. One puzzle is that the potential repertoire greatly exceeds the realized diversity of naïve T cells within any individual. We show that the existing hypotheses fail to explain why the immune system has the potential to generate far more diversity than is used in an individual, and propose an alternative hypothesis of “evolutionary sloppiness.” Another immunological puzzle is why mice and humans have similar repertoires even though humans have over 1000-fold more T cells. We discuss how the idea of the “protecton,” the smallest unit of protection, might explain this discrepancy and estimate the size of “protecton” based on available precursor frequencies data. We then consider T cell cross-reactivity – the ability of a T cell clone to respond to more than one epitope. We extend existing calculations to estimate the extent of expected cross-reactivity between the responses to different pathogens. Our results are consistent with two observations: a low probability of observing cross-reactivity between the immune responses to two randomly chosen pathogens; and the ensemble of memory cells being sufficiently diverse to generate cross-reactive responses to new pathogens.
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Affiliation(s)
| | - Brian D Evavold
- Department of Microbiology and Immunology, Emory University , Atlanta, GA , USA
| | - Louis N Schoettle
- Center for Infectious Diseases and Vaccinology, School of Life Sciences, Arizona State University , Tempe, AZ , USA
| | - Joseph N Blattman
- Center for Infectious Diseases and Vaccinology, School of Life Sciences, Arizona State University , Tempe, AZ , USA
| | - Rustom Antia
- Department of Biology, Emory University , Atlanta, GA , USA
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10
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Arsenović-Ranin N, Perišic M, Bufan B, Stojić-Vukanić Z, Pilipović I, Kosec D, Leposavić G. Ovarian hormone withdrawal in prepubertal developmental stage does not prevent thymic involution in rats. Exp Biol Med (Maywood) 2013; 238:641-57. [PMID: 23918876 DOI: 10.1177/1535370213489475] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The study was undertaken to assess the effects of ovarian hormone withdrawal in prepubertal age on thymopoiesis in 2- (young) and 11-month-old (middle-aged) rats. In ovariectomized (Ox) rats, irrespective of age, thymic weight and cellularity were greater than in age-matched controls, but the values of both parameters exhibited the age-related decline. In addition, although thymopoietic efficiency was increased in both groups of Ox rats when compared with age-matched controls, thymopoiesis exhibited the age-related decline mirrored in the lower numbers of both CD4+ and CD8+ recent thymic emigrants in peripheral blood. This reflected the prethymic changes affecting bone marrow progenitor generation/entry and the thymic alterations encompassing the impaired progenitor progression through early pre-T-cell receptor developmental stages (defined by CD45RC/CD2 expression) and, possibly, a more pronounced decrease in the proliferation of the most mature thymocytes. Apart from the changes at thymocyte level, in Ox rats the age-related alterations in thymic stroma (substantiated in a prominent loss of thymic epithelial cells) were registered. Ovariectomy-induced changes in thymic lymphoid and epithelial component, most probably, influenced each other leading to the increase in thymic expression of interleukin-6 and interleukin-7 mRNAs along with time after ovariectomy. Collectively, the study showed that the withdrawal of ovarian hormones in prepubertal age increases the efficiency of thymopoiesis in young adult rats, but does not prevent decline in thymopoiesis occurring with age.
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Affiliation(s)
- Nevena Arsenović-Ranin
- Department of Microbiology and Immunology, Faculty of Pharmacy, University of Belgrade, 11221 Belgrade, Serbia
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Oh-Hora M, Komatsu N, Pishyareh M, Feske S, Hori S, Taniguchi M, Rao A, Takayanagi H. Agonist-selected T cell development requires strong T cell receptor signaling and store-operated calcium entry. Immunity 2013; 38:881-95. [PMID: 23499491 DOI: 10.1016/j.immuni.2013.02.008] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 02/11/2013] [Indexed: 01/08/2023]
Abstract
T cell receptor (TCR) signaling driven by interaction of the TCR with specific complexes of self-peptide and the major histocompatibility complex determines T cell fate in thymic development. However, the signaling pathway through which TCR signal strength regulates distinct T cell lineages remains unknown. Here we have used mice lacking the endoplasmic reticulum Ca2+ sensors stromal interaction molecule 1 (STIM1) and STIM2 to show that STIM-induced store-operated Ca2+ entry is not essential for thymic development of conventional TCRαβ+ T cells but is specifically required for the development of agonist-selected T cells (regulatory T cells, invariant natural killer T cells, and TCRαβ+ CD8αα+ intestinal intraepithelial lymphocytes). The severe impairment of agonist-selected T cell development is mainly due to a defect in interleukin-2 (IL-2) or IL-15 signaling. Thus, STIM1 and STIM2-mediated store-operated Ca2+ influx, leading to efficient activation of NFAT (nuclear factor of activated T cells), is critical for the postselection maturation of agonist-selected T cells.
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Affiliation(s)
- Masatsugu Oh-Hora
- Department of Cell Signaling, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
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12
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Leposavic G, Perisic M, Pilipovic I. Role of gonadal hormones in programming developmental changes in thymopoietic efficiency and sexual diergism in thymopoiesis. Immunol Res 2012; 52:7-19. [PMID: 22407539 DOI: 10.1007/s12026-012-8278-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
There is a growing body of evidence indicating the important role of the neonatal steroid milieu in programming sexually diergic changes in thymopoietic efficiency, which in rodents occur around puberty and lead to a substantial phenotypic and functional remodeling of the peripheral T-cell compartment. This in turn leads to an alteration in the susceptibility to infection and various immunologically mediated pathologies. Our laboratory has explored interdependence in the programming and development of the hypothalamo-pituitary-gonadal axis and thymus using experimental model of neonatal androgenization. We have outlined critical points in the complex process of T-cell development depending on neonatal androgen imprinting and the peripheral outcome of these changes and have pointed to underlying mechanisms. Our research has particularly contributed to an understanding of the putative role of changes in catecholamine-mediated communications in the thymopoietic alterations in adult neonatally androgenized rats.
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Affiliation(s)
- Gordana Leposavic
- Department of Physiology, Faculty of Pharmacy, University of Belgrade, 450 Vojvode Stepe, 11221 Belgrade, Serbia.
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Pilipović I, Radojević K, Perišić M, Leposavić G. Glucocorticoid-catecholamine interplay within the composite thymopoietic regulatory network. Ann N Y Acad Sci 2012; 1261:34-41. [DOI: 10.1111/j.1749-6632.2012.06623.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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Radojević K, Kosec D, Perišić M, Pilipović I, Vidić-Danković B, Leposavić G. Neonatal androgenization affects the efficiency of β-adrenoceptor-mediated modulation of thymopoiesis. J Neuroimmunol 2011; 239:68-79. [PMID: 21940054 DOI: 10.1016/j.jneuroim.2011.08.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 08/25/2011] [Accepted: 08/31/2011] [Indexed: 01/29/2023]
Abstract
We tested the hypothesis that neonatal androgenization affects the efficacy of β-adrenoceptor (β-AR)-mediated fine tuning of thymopoiesis in adult female rats by modulating the thymic noradrenaline (NA) level and/or β-AR expression. In adult rats administered with 1000 μg testosterone enanthate at postnatal day 2 a higher density of catecholamine (CA)-synthesizing thymic cells, including thymocytes, and a rise in their CA content was found. In addition, in these animals increased thymic noradrenergic nerve fiber fluorescence intensity, reflecting their increased CA content, was detected. These changes were followed by an increase in thymic NA concentration. The rise in thymic NA content in thymic nerve fibers and cells was associated with changes in the expression of mRNA for enzymes controlling pivotal steps in NA biosynthesis (tyrosine hydroxylase, dopamine-β-hydroxylase) and inactivation (monoamine oxidase). In contrast, the thymic level of β(2)-AR mRNA on a per cell basis and the receptor surface density on thymocytes was reduced in testosterone-treated (TT) rats. As a consequence, 14-day-long treatment with propranolol, a β-AR blocker, was ineffective in modulating T-cell differentiation/maturation in TT rats. In conclusion, the study indicates the importance of the neonatal sex steroid milieu for shaping the immunomodulatory capacity of the thymic NA/β-AR signaling system in adult rats.
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Affiliation(s)
- Katarina Radojević
- Institute of Virology, Vaccines and Sera Torlak, 458 Vojvode Stepe, Belgrade, Serbia
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15
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Takahama Y, Nitta T, Mat Ripen A, Nitta S, Murata S, Tanaka K. Role of thymic cortex-specific self-peptides in positive selection of T cells. Semin Immunol 2010; 22:287-93. [DOI: 10.1016/j.smim.2010.04.012] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Accepted: 04/23/2010] [Indexed: 01/22/2023]
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16
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Affiliation(s)
- Masatsugu Oh-hora
- Department of Cell Signaling, Graduate School, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, Japan.
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17
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Dalheimer SL, Zeng L, Draves KE, Hassaballa A, Jiwa NN, Parrish TD, Clark EA, Yankee TM. Gads-deficient thymocytes are blocked at the transitional single positive CD4+ stage. Eur J Immunol 2009; 39:1395-404. [PMID: 19337995 DOI: 10.1002/eji.200838692] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Positive selection of T-cell precursors is the process by which a diverse T-cell repertoire is established. Positive selection begins at the CD4(+)CD8(+) double positive (DP) stage of development and involves at least two steps. First, DP thymocytes down-regulate CD8 to become transitional single positive (TSP) CD4(+) thymocytes. Then, cells are selected to become either mature single positive CD4(+) or mature single positive CD8(+) thymocytes. We sought to define the function of Gads during the two steps of positive selection by analyzing a Gads-deficient mouse line. In Gads(+/+) mice, most TSP CD4(+) thymocytes are TCR(hi)Bcl-2(hi)CD69(+), suggesting that essential steps in positive selection occurred in the DP stage. Despite that Gads(-/-) mice could readily generate TSP CD4(+) thymocytes, many Gads(-/-) TSP CD4(+) cells were TCR(lo)Bcl-2(lo)CD69(-), suggesting that Gads(-/-) cells proceeded to the TSP CD4(+) stage prior to being positively selected. These data suggest that positive selection is not a prerequisite for the differentiation of DP thymocytes into TSP CD4(+) thymocytes. We propose a model in which positive selection and differentiation into the TSP CD4(+) stage are separable events and Gads is only required for positive selection.
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Affiliation(s)
- Stacy L Dalheimer
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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18
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Role of ovarian hormones in age-associated thymic involution revisited. Immunobiology 2009; 215:275-93. [PMID: 19577818 DOI: 10.1016/j.imbio.2009.06.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Revised: 06/08/2009] [Accepted: 06/08/2009] [Indexed: 01/01/2023]
Abstract
A commonly held view that ovarian hormones are causally involved in age-associated thymic involution has been recently challenged. In particular, their relevance in the progression of thymic involution has been disputed. To reassess this issue 10-month-old rats with well advanced thymic involutive changes were ovariectomized (Ovx), and after 1 month thymic cellularity, thymocyte development and levels of recent thymic emigrants (RTEs) were examined in peripheral blood and spleen. In addition, the distribution of major conventional and regulatory T-cell subsets was analyzed in the same peripheral lymphocyte compartments. Ovariectomy increased thymic weight and cellularity above the levels in both 10-month-old and age-matched controls indicating that ovarian hormone ablation not only prevented further progression of thymic involution, but also reversed it. The increased thymic cellularity was accompanied by altered thymocyte differentiation/maturation culminating in increased thymic output of naïve T cells as indicated by elevated levels of both CD4+ and CD8+ RTEs in peripheral blood and spleen. The changes in T-cell development produced: (i) a disproportional increase in cellularity across thymocyte subsets, so that relative proportions of cells at all maturational stages preceding the CD4+CD8+ T cell receptor (TCR)alphabeta(low) stage were reduced; the relative numbers of CD4+CD8+ TCRalphabeta(low) cells entering positive selection and their immediate CD4+CD8+ TCRalphabeta(high) descendents were increased, while those of the most mature CD4+CD8- and CD4-CD8+ TCRalphabeta(high) cells remained unaltered; (ii) enhanced cell proliferation across all thymocyte subsets and (iii) reduced apoptosis of cells within the CD4+CD8+ thymocyte subset. The augmented thymic output of naïve T cells in Ovx rats most likely reflected an early disinhibition of thymocyte development followed by increased positive/reduced negative selection, at least partly, due to raised thymocyte surface Thy-1 expression. The greater number of CD4+CD25+Foxp3+ cells in both thymus and peripheral blood suggested augmented thymic production of these cells. In addition, an increased CD4+/CD8+ cell ratio was found in the spleen of Ovx rats. Thus, ovarian hormone ablation led not only to increased diversity of the T-cell repertoire, but also to a new balance among distinct T-cell subsets in the periphery.
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Stojić-Vukanić Z, Rauski A, Kosec D, Radojević K, Pilipović I, Leposavić G. Dysregulation of T-cell development in adrenal glucocorticoid-deprived rats. Exp Biol Med (Maywood) 2009; 234:1067-74. [PMID: 19546352 DOI: 10.3181/0902-rm-63] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A number of different experimental approaches have been used to elucidate the impact of basal levels of adrenal gland-derived glucocorticoids (GCs) on T cell development, and thereby T cell-mediated immune responses. However, the relevance of the adrenal GCs to T cell development is still far from clear. This study was undertaken to explore the relevance of basal levels of GCs to T cell differentiation/maturation. Eight days post-adrenalectomy in adult male rats the thymocyte yield, apoptotic and proliferative rate and the relationship amongst major thymocyte subsets, as defined by TCRalphabeta/CD4/CD8 expression, were examined using flow cytometry. Adrenal GC deprivation decreased thymocyte apoptosis and altered the kinetics of T cell differentiation/maturation. In the adrenalectomized rats there was increased thymic hypercellularity and an over-representation of the CD4+CD8+ double positive (DP) TCRalphabeta(low) cells entering selection, as well as increased numbers of their DP TCRalphabeta(-) immediate precursors. These changes were accompanied with under-representation of the postselected DP TCRalphabeta(high) and the most mature CD4-CD8+ and, particularly, CD4+CD8- single positive (SP) TCRalphabeta(high) cells. This data suggests that withdrawal of adrenal GCs produces alterations in the thymocyte selection processes, possibly affecting the diversity of functional T cell repertoire and generation of potentially self-reactive cells as indicated by the reduced proportion and number of CD4-CD8- double negative TCRalphabeta(high) cells. In addition, it indicates that GCs influence the post-selection maturation of thymocytes and plays a regulatory role in controlling the ratio of mature CD4+CD8-/CD4-CD8+ SP TCRalphabeta(high) cells.
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Affiliation(s)
- Zorica Stojić-Vukanić
- Department of Microbiology and Immunology, Faculty of Pharmacy, University of Belgrade, 11221 Belgrade, Serbia
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20
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Leposavić G, Perisić M, Kosec D, Arsenović-Ranin N, Radojević K, Stojić-Vukanić Z, Pilipović I. Neonatal testosterone imprinting affects thymus development and leads to phenotypic rejuvenation and masculinization of the peripheral blood T-cell compartment in adult female rats. Brain Behav Immun 2009; 23:294-304. [PMID: 19028560 DOI: 10.1016/j.bbi.2008.11.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 10/19/2008] [Accepted: 11/02/2008] [Indexed: 12/27/2022] Open
Abstract
Exposure of female rodents to testosterone in the critical neonatal period produces defeminization/masculinization of the hypothalamo-pituitary-gonadal (HPG) axis, i.e. neonatal androgenization and postpones axis maturation. To address the hypothesis that HPG axis signaling is involved in the programming of thymic maturation/involution and sexual differentiation we studied the impact of neonatal androgenization on thymic cellularity, development of effector and regulatory T cells, and phenotypic characteristics of peripheral blood T lymphocytes in adult rats. A single injection of testosterone on postnatal day 2 postponed thymic maturation/involution as revealed by organ hypercellularity, increased cellularity of the most mature (CD4+CD8- and CD4-CD8+) TCRalphabeta(high) thymocyte and both recent thymic emigrant (RTE) subsets and caused phenotypic defeminization/masculinization of thymic (decreased CD4+CD8-TCRalphabeta(high)/CD4-CD8+TCRalphabeta(high) cell ratio) and peripheral blood T-cell compartments (decreased CD4+RTE/CD8+RTE and CD4+/CD8+ cell ratio). In addition, neonatal androgenization increased the relative and absolute numbers of both CD4+CD25+Foxp3+ and natural killer (NK) regulatory T cells in peripheral blood. These findings, in conjunction with thymocyte overexpression of Thy-1 that is assumed to reduce negative selection affecting self-reactive cell generation, suggest a new relationship between self-reactive and regulatory T cells. In conclusion, our study provides additional evidence for a role of HPG signals (i.e. sex steroids and gonadotropins) in programming the kinetics of thymic maturation/involution and in establishing immunological sexual dimorphism.
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Affiliation(s)
- Gordana Leposavić
- Immunology Research Centre Branislav Janković, Institute of Virology, Vaccines and Sera Torlak, 458 Vojvode Stepe, 11221 Belgrade, Serbia.
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21
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Ge Q, Chen W. Characterization of a murine thymic CD4(+) T cell subset-TCRalphabeta (+) 3G11 (-) 6C10 (-) CD4 (+) CD8 (-) thymocytes. SCIENCE IN CHINA. SERIES C, LIFE SCIENCES 2008; 42:441-8. [PMID: 18763136 DOI: 10.1007/bf02882065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/1999] [Indexed: 11/25/2022]
Abstract
The presence of a relatively mature CD4(+) CD8(-) (SP) T cell subset in mouse thymus has been demonstrated. Composing of 10% of total CD4SP thymocytes, this subset is defined by the absence of 3G11 and 6C10 expression with a phenotype of CD69(+/-), HSA(med/lo) and heterogeneous for Qa-2 expression. The proliferation capability of TCRalphabeta(+) 3Gl l(-) 6C10(-) CD4(+) CD8(-) thymocytes was high while using Con A stimulus. And Con A stimulation could result in secretion of IL4, IL-10, IL-6 and a little amount of IFNgamma. IL-2 was barely detectable. This is distinct from typical Th0 type cytokines. The cells of this subset were NK1.1 negative, but strongly expressed GATA-3 mRNA. The results suggest that the CD4(+) subset of 3G11(-) 6C10(-) NK1.1(-) phenotype possesses immunocompetent cells with functions characteristic of Th2-like cytokines, which may indicate the cells at transitional status from Th0 to Th2, with a propensity to Th2.
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Affiliation(s)
- Q Ge
- Department of Immunology, Beijing Medical University, 100083, Beijing, China
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22
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Gallo EM, Winslow MM, Canté-Barrett K, Radermacher AN, Ho L, McGinnis L, Iritani B, Neilson JR, Crabtree GR. Calcineurin sets the bandwidth for discrimination of signals during thymocyte development. Nature 2008; 450:731-5. [PMID: 18046413 DOI: 10.1038/nature06305] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Accepted: 09/26/2007] [Indexed: 01/15/2023]
Abstract
At critical times in development, cells are able to convert graded signals into discrete developmental outcomes; however, the mechanisms involved are poorly understood. During thymocyte development, cell fate is determined by signals originating from the alphabeta T-cell receptor. Low-affinity/avidity interactions between the T-cell receptor and peptide-MHC complexes direct differentiation to the single-positive stage (positive selection), whereas high-affinity/avidity interactions induce death by apoptosis (negative selection). Here we show that mice deficient in both calcineurin and nuclear factor of activated T cells (NFAT)c2/c3 lack a population of preselection thymocytes with enhanced ability to activate the mitogen-activated protein kinase (Raf-MEK-ERK) pathway, and fail to undergo positive selection. This defect can be partially rescued with constitutively active Raf, indicating that calcineurin controls MAPK signalling. Analysis of mice deficient in both Bim (which is required for negative selection) and calcineurin revealed that calcineurin-induced ERK (extracellular signal-regulated kinase) sensitization is required for differentiation in response to 'weak' positive selecting signals but not in response to 'strong' negative selecting signals (which normally induce apoptosis). These results indicate that early calcineurin/NFAT signalling produces a developmental period of ERK hypersensitivity, allowing very weak signals to induce positive selection. This mechanism might be generally useful in the discrimination of graded signals that induce different cell fates.
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Affiliation(s)
- Elena M Gallo
- Howard Hughes Medical Institute and the Department of Pathology, Stanford University, Stanford, California 94305, USA
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23
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Cai AQ, Landman KA, Hughes BD, Witt CM. T cell development in the thymus: From periodic seeding to constant output. J Theor Biol 2007; 249:384-94. [PMID: 17869276 DOI: 10.1016/j.jtbi.2007.07.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Revised: 07/27/2007] [Accepted: 07/27/2007] [Indexed: 11/15/2022]
Abstract
T cell development occurs in the thymus throughout life. Recent experimental findings show that the seeding of the thymus by multi-potent stem cells from the bone marrow is periodic rather than continuous, as previously assumed. However it is well known that the output rate of cells from the thymus is relatively constant. A quantitative model is used to verify the current hypotheses regarding T cell development in the steady state mouse thymus. The results show that the thymus could be at a periodic steady state with out-of-phase thymocyte populations. Experiments to examine possible periodic fluctuations in the thymus are proposed and methods for further analysis are outlined.
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Affiliation(s)
- Anna Q Cai
- Department of Mathematics and Statistics, The University of Melbourne, Vic. 3010, Australia
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24
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Pesić V, Plećas-Solarović B, Radojević K, Kosec D, Pilipović I, Perisić M, Leposavić G. Long-term beta-adrenergic receptor blockade increases levels of the most mature thymocyte subsets in aged rats. Int Immunopharmacol 2007; 7:674-86. [PMID: 17386415 DOI: 10.1016/j.intimp.2007.01.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Revised: 01/18/2007] [Accepted: 01/23/2007] [Indexed: 11/27/2022]
Abstract
Age-related increase in the density of thymic noradrenergic fibres and noradrenaline (NA) concentration is proposed to be associated with thymic involution and altered thymopoiesis. To test this hypothesis thymocyte differentiation/maturation and thymic structure were studied in 18-month-old male Wistar rats subjected to 14-day-long propranolol (P) blockade of beta-adrenoceptors (beta-ARs). The treatment primarily resulted in changes in the T-cell receptor (TCR)-dependent stages of thymopoiesis, which led to an increase in both the relative and absolute numbers of the most mature single positive (SP) CD4(+)CD8(-) (including cells with the CD4(+)CD25(+) regulatory phenotype) and CD4(-)CD8(+) TCRalphabeta(high) thymocytes. Accordingly, in the thymi of these rats an increase in both numerical density and absolute number of medullary thymocytes encompassing mainly the most mature SP cells was found. These findings, together with an increase in the thymocyte surface expression of the regulatory molecule Thy-1 (CD90) (implicated in negative regulation of TCRalphabeta-dependent thymocyte selection thresholds) in the same rats, may suggest increased positive/reduced negative thymocyte selection. Collectively, the results indicate that a decline in thymic efficiency in generating both conventional and regulatory T cells, and consequently in immune function, in aged rats may be, at least partly, attenuated by long-term blockade of beta-ARs with P.
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Affiliation(s)
- V Pesić
- Department of Physiology, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade, Republic of Serbia
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25
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Leposavić G, Radojević K, Vidić-Danković B, Kosec D, Pilipović I, Perisić M. Early postnatal castration affects thymic and thymocyte noradrenaline levels and beta-adrenoceptor-mediated influence on the thymopoiesis in adult rats. J Neuroimmunol 2006; 182:100-15. [PMID: 17141332 DOI: 10.1016/j.jneuroim.2006.10.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2006] [Revised: 10/06/2006] [Accepted: 10/06/2006] [Indexed: 11/22/2022]
Abstract
The interactions among the nervous, endocrine and immune system were studied by examining: i) thymic and thymocyte catecholamine levels in adult rats castrated (Cx) at postnatal day 3 and ii) effects of 14-day-long propranolol (P) treatment on main thymocyte differentiational molecule expression in adult non-Cx and Cx rat. The results demonstrated that castration in early postnatal period lowers levels of both neurally- and thymocyte-derived noradrenaline in adult rats, and thereby diminishes beta-adrenoceptor-mediated fine tuning of the T-cell differentiation/maturation. In non-Cx rats P affected TCRalphabeta-dependent stages of thymocyte differentiation/maturation decreasing frequency of CD4+8+ double positive (DP) TCRalphabeta(low) cells entering selection processes and increasing relative number of positively selected DP TCRalphabeta(high) (most likely due to an increased thymocyte surface density of Thy-1 that is involved in negative control of TCRalphabeta-mediated signaling/selection thresholds) and the most mature CD4+8- TCRalphabeta(high) cells (including CD4+25+ regulatory cells). However, in Cx rats P failed to produce any significant changes in thymocyte subset composition.
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Affiliation(s)
- Gordana Leposavić
- Immunology Research Centre Branislav Janković, Institute of Immunology and Virology Torlak, Belgrade, Serbia.
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26
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David-Fung ES, Yui MA, Morales M, Wang H, Taghon T, Diamond RA, Rothenberg EV. Progression of regulatory gene expression states in fetal and adult pro-T-cell development. Immunol Rev 2006; 209:212-36. [PMID: 16448545 PMCID: PMC4157939 DOI: 10.1111/j.0105-2896.2006.00355.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Precursors entering the T-cell developmental pathway traverse a progression of states characterized by distinctive patterns of gene expression. Of particular interest are regulatory genes, which ultimately control the dwell time of cells in each state and establish the mechanisms that propel them forward to subsequent states. Under particular genetic and developmental circumstances, the transitions between these states occur with different timing, and environmental feedbacks may shift the steady-state accumulations of cells in each state. The fetal transit through pro-T-cell stages is faster than in the adult and subject to somewhat different genetic requirements. To explore causes of such variation, this review presents previously unpublished data on differentiation gene activation in pro-T cells of pre-T-cell receptor-deficient mutant mice and a quantitative comparison of the profiles of transcription factor gene expression in pro-T-cell subsets of fetal and adult wildtype mice. Against a background of consistent gene expression, several regulatory genes show marked differences between fetal and adult expression profiles, including those encoding two basic helix-loop-helix antagonist Id factors, the Ets family factor SpiB and the Notch target gene Deltex1. The results also reveal global differences in regulatory alterations triggered by the first T-cell receptor-dependent selection events in fetal and adult thymopoiesis.
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Abstract
Recent elucidation of the role of central tolerance in preventing organ-specific autoimmunity has changed our concepts of self/nonself discrimination. This paradigmatic shift is largely attributable to the discovery of promiscuous expression of tissue-restricted self-antigens (TRAs) by medullary thymic epithelial cells (mTECs). TRA expression in mTECs mirrors virtually all tissues of the body, irrespective of developmental or spatio-temporal expression patterns. This review summarizes current knowledge on the cellular and molecular regulation of TRA expression in mTECs, outlines relevant mechanisms of antigen presentation and modes of tolerance induction, and discusses implications for the pathogenesis of autoimmune diseases and other biological processes such as fertility, pregnancy, puberty, and tumor defense.
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Affiliation(s)
- Bruno Kyewski
- Division of Developmental Immunology, Tumor Immunology Program, German Cancer Research Center, 69120 Heidelberg, Germany.
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28
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Leposavić G, Pesić V, Kosec D, Radojević K, Arsenović-Ranin N, Pilipović I, Perisić M, Plećas-Solarović B. Age-associated changes in CD90 expression on thymocytes and in TCR-dependent stages of thymocyte maturation in male rats. Exp Gerontol 2006; 41:574-89. [PMID: 16632291 DOI: 10.1016/j.exger.2006.03.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2005] [Revised: 03/01/2006] [Accepted: 03/07/2006] [Indexed: 01/28/2023]
Abstract
To elucidate the effects of ageing on T-cell-maturation, in 3- and 18-month-old rats, we analysed the expression of: (i) CD4/CD8/TCRalphabeta and (ii) Thy-1, which is supposed to be a regulator of TCRalphabeta signalling, and thereby the thymocyte selection thresholds. Since an essential role for TCRalphabeta signalling in the development of CD4+25+T(reg)-cells was suggested, the frequency of these cells was also quantified. We demonstrated that, as for mice, early thymocyte differentiational steps within the CD4-8- double negative (DN) developmental stage are age-sensitive. Furthermore, we revealed that TCRalphabeta-dependent stages of T-cell development are affected by ageing, most likely due to an impaired expression of Thy-1 on TCRalphabeta(low) thymocytes entering selection processes. The diminished frequency of the post-selection CD4+8+ double positive (DP) cells in aged rats, together with an overrepresentation of mature single positive (SP) cells, most probably suggests more efficient differentiational transition from the DP TCRalphabeta(high) to the SP TCRalphabeta(high) developmental stage, which is followed by an increase in pre-migration proliferation of the mature SP cells. Moreover, the study indicated impaired intrathymic generation of CD4+25+T(reg)-cells in aged rats, thus providing a possible explanation for the increased frequency of autoimmune diseases in ageing.
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MESH Headings
- Aging/immunology
- Animals
- Antigens, Surface/genetics
- Antigens, Surface/physiology
- Apoptosis/physiology
- Autoimmune Diseases/immunology
- CD4 Antigens/genetics
- CD4 Antigens/physiology
- CD8 Antigens/genetics
- CD8 Antigens/physiology
- Cell Movement
- Cell Proliferation
- Gene Expression Regulation
- Interleukin-2 Receptor alpha Subunit/genetics
- Interleukin-2 Receptor alpha Subunit/physiology
- Lectins, C-Type/genetics
- Lectins, C-Type/physiology
- Male
- NK Cell Lectin-Like Receptor Subfamily B
- Rats
- Rats, Wistar
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/physiology
- Thy-1 Antigens/genetics
- Thy-1 Antigens/metabolism
- Thymus Gland/cytology
- Thymus Gland/immunology
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Affiliation(s)
- Gordana Leposavić
- Institute of Immunology and Virology Torlak, Immunology Research Center Branislav Janković, Belgrade, Serbia and Montenegro.
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29
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Abstract
Intracellular signals arising from interactions of immature thymocytes with distinct populations of stromal cells in the thymus are central to T cell development. The characteristics of these signals and the mechanisms underlying thymocyte migration between stromal cell compartments have been difficult to identify from static measurements of fixed tissue. Recent advances in two-photon microscopy and the development of three-dimensional models for real-time studies of T cell development have shed light on how single cells navigate the thymus. These studies reveal crosstalk between thymocyte signaling and motility that may integrate the search for potentially rare self-antigens with the requirement for sustained signaling in T cell maturation.
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Affiliation(s)
- Nirav R Bhakta
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Beckman Center Rm B-111A, Stanford CA 94305, USA
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30
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Bhakta NR, Oh DY, Lewis RS. Calcium oscillations regulate thymocyte motility during positive selection in the three-dimensional thymic environment. Nat Immunol 2005; 6:143-51. [PMID: 15654342 DOI: 10.1038/ni1161] [Citation(s) in RCA: 200] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2004] [Accepted: 12/20/2004] [Indexed: 11/08/2022]
Abstract
The three-dimensional thymic microenvironment and calcium signaling pathways are essential for driving positive selection of developing T cells. However, the nature of calcium signals and the diversity of their effects in the thymus are unknown. We describe here a thymic slice preparation for visualizing thymocyte motility and signaling in real time with two-photon microscopy. Naive thymocytes were highly motile at low intracellular calcium concentrations, but during positive selection cells became immobile and showed sustained calcium concentration oscillations. Increased intracellular calcium was necessary and sufficient to arrest thymocyte motility. The calcium dependence of motility acts to prolong thymocyte interactions with antigen-bearing stromal cells, promoting sustained signaling that may enhance the expression of genes underlying positive selection.
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Affiliation(s)
- Nirav R Bhakta
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305, USA
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31
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El Kassar N, Lucas PJ, Klug DB, Zamisch M, Merchant M, Bare CV, Choudhury B, Sharrow SO, Richie E, Mackall CL, Gress RE. A dose effect of IL-7 on thymocyte development. Blood 2004; 104:1419-27. [PMID: 15155461 DOI: 10.1182/blood-2004-01-0201] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To study interleukin-7 (IL-7) in early thymocyte development, we generated mice transgenic (Tg) for the IL-7 gene under control of the lck proximal promoter. Founder line TgA, with the lowest level of IL-7 overexpression, showed enhanced alphabeta T-cell development. In contrast, in the highest overexpressing founder line, TgB, alphabeta T-cell development was disturbed with a block at the earliest intrathymic precursor stage. This was due to decreased progenitor proliferation as assessed by Ki-67 staining and in vivo bromodeoxyuridine (BrdU) incorporation. Bcl-2 was up-regulated in T-cell-committed progenitors in all Tg lines, and accounted for greater numbers of double positive (DP), CD4 single positive (SP), and CD8SP thymocytes in TgA mice where, in contrast to TgB mice, thymocyte progenitor proliferation was normal. Mixed marrow chimeras using TgB(+) and congenic mice as donors, and experiments using anti-IL-7 monoclonal antibody (MAb) in vivo, confirmed the role of IL-7 protein in the observed TgB phenotype. In conclusion, at low Tg overexpression, IL-7 enhanced alphabeta T-cell development by increasing thymocyte progenitor survival, while at high overexpression IL-7 reduces their proliferation, inducing a dramatic block in DP production. These results show for the first time in vivo a dose effect of IL-7 on alphabeta T-cell development and have implications for IL-7 in the clinical setting.
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MESH Headings
- Animals
- B-Lymphocytes/cytology
- B-Lymphocytes/physiology
- Cell Division/immunology
- Gene Expression Regulation, Developmental/immunology
- Interleukin-7/genetics
- Killer Cells, Natural/cytology
- Killer Cells, Natural/physiology
- Leukocyte Common Antigens/metabolism
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Promoter Regions, Genetic
- Proto-Oncogene Proteins c-bcl-2/metabolism
- RNA, Messenger/metabolism
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Stem Cells/cytology
- Stem Cells/physiology
- T-Lymphocytes/cytology
- T-Lymphocytes/physiology
- Thymus Gland/cytology
- Thymus Gland/embryology
- Thymus Gland/physiology
- Up-Regulation/immunology
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Affiliation(s)
- Nahed El Kassar
- Experimental Immunology Branch, National Institutes of Health, 10 Center Drive, Bldg 10 Rm 4B36, Bethesda, MD 20892-1360, USA
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32
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Rochard P, Galiegue S, Tinel N, Peleraux A, Bord A, Jbilo O, Casellas P. Expression of the peripheral benzodiazepine receptor triggers thymocyte differentiation. Gene Expr 2004; 12:13-27. [PMID: 15473257 PMCID: PMC6009102 DOI: 10.3727/000000004783992170] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/02/2004] [Indexed: 11/24/2022]
Abstract
In the thymus, during T-cell differentiation, the expression of the peripheral benzodiazepine receptor (PBR) modulates. The protein level decreases between the double negative and double positive stages, and then increases when thymocytes become single positive. We addressed the role played by PBR in T-cell maturation. To this aim, we used Jurkat cells, which are immature T lymphocytes derived from an acute lymphoblastic leukemia. These cells are PBR negative and were stably transfected to achieve PBR levels similar to that in mature T cells. Using the DNA chip technology, we analyzed the PBR expression-dependent gene changes and evidenced that PBR-expressing cells exhibited more mature features than mock-transfected ones. A majority of the modulated genes encode proteins playing direct or indirect roles during the lymphocyte maturation process. In particular, PBR expression induced several differentiation markers (such as CD1, CD6), or key regulating elements (e.g., RAG1, RAG2, CD99, TCR). By contrast, some regulators of TCR signaling were reduced. PBR expression also affected the expression of critical apoptosis regulators: the proapoptotic lipocortin I, galectin-1, and galectin-9 were reduced while the antiapoptotic Bcl-2 was induced. Altogether our results supported the hypothesis that PBR controls T-cell maturation and suggested mechanisms through which PBR may regulate thymocyte-positive selection.
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Affiliation(s)
- Pierrick Rochard
- Immunology-Oncology Department, Sanofi-Synthelabo Recherche, 371 rue du Professeur Joseph Blayac, 34184 Montpellier cedex 04, France
| | - Sylvaine Galiegue
- Immunology-Oncology Department, Sanofi-Synthelabo Recherche, 371 rue du Professeur Joseph Blayac, 34184 Montpellier cedex 04, France
| | - Norbert Tinel
- Immunology-Oncology Department, Sanofi-Synthelabo Recherche, 371 rue du Professeur Joseph Blayac, 34184 Montpellier cedex 04, France
| | - Annick Peleraux
- Immunology-Oncology Department, Sanofi-Synthelabo Recherche, 371 rue du Professeur Joseph Blayac, 34184 Montpellier cedex 04, France
| | - Annie Bord
- Immunology-Oncology Department, Sanofi-Synthelabo Recherche, 371 rue du Professeur Joseph Blayac, 34184 Montpellier cedex 04, France
| | - Omar Jbilo
- Immunology-Oncology Department, Sanofi-Synthelabo Recherche, 371 rue du Professeur Joseph Blayac, 34184 Montpellier cedex 04, France
| | - Pierre Casellas
- Immunology-Oncology Department, Sanofi-Synthelabo Recherche, 371 rue du Professeur Joseph Blayac, 34184 Montpellier cedex 04, France
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33
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Lee SJE, Hori Y, Chakraborty AK. Low T cell receptor expression and thermal fluctuations contribute to formation of dynamic multifocal synapses in thymocytes. Proc Natl Acad Sci U S A 2003; 100:4383-8. [PMID: 12671067 PMCID: PMC153563 DOI: 10.1073/pnas.0630563100] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2002] [Accepted: 01/29/2003] [Indexed: 11/18/2022] Open
Abstract
Mature T cell activation and selection of immature T cells (thymocytes) are both initiated by binding of T cell receptor (TCR) molecules on the surface of T cells to MHC peptide (MHCp) molecules on the surface of antigen-presenting cells. Recent experiments have shown that the spatial pattern of receptors and ligands in the intercellular junction (synapse) is different during thymocyte selection compared with mature T cell activation. Using a statistical mechanical model, we show that lower TCR expression in thymocytes contributes to effecting these differences. An analogy with the phase behavior of simple fluids helps clarify how, for low TCR expression, thermal fluctuations lead to the dynamic synapse patterns observed for thymocytes. We suggest that a different synapse pattern resulting from lower TCR expression, which could mediate differential signaling, may be the reason why TCR expression level is low in thymocytes.
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Affiliation(s)
- Sung-Joo E Lee
- Biophysics Graduate Group, University of California, Berkeley, CA 94720, USA
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34
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Tiong Ong S, Ly C, Nguyen M, Kay Brightman B, Fan H. Expression profiling of a transformed thymocyte cell line undergoing maturation in vitro identifies multiple genes involved in positive selection. Cell Immunol 2003; 221:64-79. [PMID: 12742383 DOI: 10.1016/s0008-8749(03)00065-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Biochemical and genetic studies of thymocyte maturation would be facilitated by the development of cultured cell lines that reflect stages of positive selection. We have derived a CD4(+)CD8(+)TCR(+) T-lymphoid cell line (M20) from a murine thymic tumor induced by a retrovirus carrying the v-myc oncogene (M-MuLV(myc)). M20 subclones undergo several aspects of positive selection in response to co-culture with a thymic stromal cell line (St3), including down-regulation of CD4 and CD8, and up-regulation of CD5 and TCR. M20 possesses a functional TCR complex, and ligation of this complex produces changes similar to co-culture with St3 stroma. Expression profiling of M20 cells in this system identified 23 genes previously shown to be important in thymocyte maturation, as well as several novel candidate genes. This system provides a new model to elucidate the molecular mechanisms of thymocyte maturation and TCR-mediated cell signaling in double-positive thymocytes.
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Affiliation(s)
- S Tiong Ong
- Division of Hematology/Oncology, Department of Medicine, College of Medicine, Irvine, CA 92697, USA
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35
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Li CL, Toda K, Saibara T, Zhang T, Ono M, Iwasaki S, Maeda T, Okada T, Hayashi Y, Enzan H, Shizuta Y, Onishi S. Estrogen deficiency results in enhanced expression of Smoothened of the Hedgehog signaling in the thymus and affects thymocyte development. Int Immunopharmacol 2002; 2:823-33. [PMID: 12095173 DOI: 10.1016/s1567-5769(02)00023-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Aromatase is an essential enzyme for estrogen synthesis. We investigated the role of estrogen in thymocyte development using aromatase-deficient (ArKO) mice. Like its role as a regulator of bone metabolism through regulating osteoprotegerin (OPG) production, estrogen is involved in the processes of thymocyte development although aromatase mRNA was not detectable in the thymus. Thymic regression and reduced cellularity were evident in ArKO mice. The major difficulties in thymocyte development of ArKO mice were observed during the CD44+ CD25- stage at the cortico-medullary junction and during the CD44- CD25- stage at the subcapsular region where the estrogen receptor was expressed in the stromal cells. The proportion of thymocytes during the CD44+ CD25- stage was reduced. The progression of CD44- CD25+ cells to the CD44- CD25- stage was accelerated in ArKO mice possibly due to insufficient osteoprotegerin production in estrogen-deficiency. However, the expression of Smoothened of the Hedgehog signaling was enhanced in CD4- CD8- double negative cells. This enhancement may result in impaired progression of CD44- CD25- cells to the CD4+ CD8+ double positive stage and impaired proliferation of CD4+ CD8+ double positive cells since Smoothened (Smo) is known to arrest cells as non-proliferating cells. This could be the reason why the proportion of CD3+ TCRbeta(high) cells during the late phase of thymocyte maturation was reduced in ArKO mice. From these observations, we propose that estrogen supports thymocyte development and maturation at many stages through many regulatory pathways including the sonic hedgehog- and the osteoprotegerin ligand (OPGL)-mediated signaling.
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Affiliation(s)
- Chun-Lin Li
- Department of Medicine, Kochi Medical School, Japan
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36
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Sinkora J, Kolínská J, Reháková Z, Cerný J, Doubravská L. Binding of the Galanthus nivalis agglutinin to thymocytes reveals alterations in surface glycosylation during T-cell development. Scand J Immunol 2002; 55:196-203. [PMID: 11896936 DOI: 10.1046/j.1365-3083.2002.01047.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Surface binding of the Galanthus nivalis agglutinin (GNA) to thymocyte subsets has been studied in pigs and rodents by multicolour flow cytometry. In all the species examined, analogous staining profiles have been recorded. Counter-staining with anti-CD3epsilon, anti-CD4 and anti-CD8 monoclonal antibodies (MoAb) revealed that a significant increase of the GNA targets on the cell surface occurred during early thymocyte differentiation and reached its maximum at the level of the CD3loCD4+CD8+ small cortical thymocyte. This was followed by a decrease in the GNA binding capacity upon terminal maturation to the single positive thymocytes. PAGE analysis has revealed a dominant GNA-binding glycoprotein (molar mass approx. 90 kDa) present on thymocyte plasma membranes and absent on the surface of splenic lymphocytes, although both the whole cell lysates from both organs contained GNA ligands of the same size. Our findings are in agreement with previous data showing that immature thymocytes differ from their mature counterparts and peripheral T lymphocytes in the surface glycosylation pattern, and support the hypothesis that lectin-glycoprotein interaction plays a significant role in the cell-to-cell crosstalk in the thymic cortex.
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Affiliation(s)
- J Sinkora
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Nový Hrádek, Czech Republic
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37
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Pettersson FE, Schneider MK, Andersson J, Grönvik KO. CD8+ T cells induce medullary thymic epithelium and CD4+CD8+CD25+ TCRbeta- thymocytes in SCID mice. Scand J Immunol 2001; 54:506-15. [PMID: 11696203 DOI: 10.1046/j.1365-3083.2001.00983.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During T-cell development the transition in the thymus of CD4-CD8- double negative (DN) progenitor T cells into CD4+CD8+ double positive (DP) cells is dependent on the expression of a T-cell receptor (TCR)-beta-chain protein. In this study purified peripheral CD4+ and CD8+ T lymphocytes from the C.B-17 strain of mice were adoptively transferred into syngeneic, neonatal SCID mice, where donor cells resided at constant numbers in thymus from 2 weeks until 10 weeks post cell transfer. In the recipient thymus the CD8+ donor cells outnumbered the CD4+ cells by a factor of three to five and both subsets contained a large fraction of activated cells. During the late phase of treatment, CD8+ T cells induced high numbers of DP thymocytes in the SCID mice, a process accompanied by the maturation of medullary epithelial cells. Such thymic development in the SCID mouse was inhibited by coresiding CD4+ donor T cells. These results indicate a regulatory role by mature peripheral T cells on medullary epithelial growth and thymocyte development in the treated SCID mice.
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Affiliation(s)
- F E Pettersson
- Department of Vaccine Research, National Veterinary Institute, Uppsala University, S-751 89 Uppsala, Sweden
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38
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He YW. The role of orphan nuclear receptor in thymocyte differentiation and lymphoid organ development. Immunol Res 2001; 22:71-82. [PMID: 11339367 DOI: 10.1385/ir:22:2-3:71] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
T lymphocytes differentiate in the thymus through several phenotypically distinct stages that are tightly regulated by multiple nuclear transcription factors. Immature CD4+CD8+ double positive (DP) thymocytes make up a majority of the population in the thymus, and exhibit several phenotypic features distinct from mature T cells. DP thymocytes express only about 10% of surface TCR that are found on mature T cells and do not proliferate and produce IL-2 in response to stimulation. Several critical events of T lymphocyte maturation such as TCRalpha gene recombination, positive and negative selection, and CD4/CD8 lineage commitment occur around the DP stage. Recent studies from our group and others on the orphan nuclear receptor RORgamma and its thymus-specific isoform RORgammat support a critical role for this nuclear receptor in the regulation of DP thymocyte function. In addition, RORgamma is required for the development of lymph nodes and Peyer's patches.
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Affiliation(s)
- Y W He
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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39
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Abstract
As a new slant on T lymphocyte repertoire selection, we have examined batteries of TCR sequences in thymi from transgenic mice engineered to exhibit limited, focussed TCR diversity. We have tracked the fate of differentiating thymocytes expressing a set of particular TCR through the positive selection process. Subtly different TCR sequences can promote different maturation pathways and commitment choices. Two distinct routes are followed by CD8-lineage cells interacting with MHC class I molecules, via TCR(hi) CD4(+)CD8(+) or CD4(+)CD8(int) intermediates, while CD4-lineage cells mature exclusively via a CD4(+)CD8(int) stage. The CD8-lineage routes are partially exclusive, indicating that the latter cell type is not always preceded by the former. The distribution of sequences also indicates that CD4 / CD8-lineage commitment is not strictly correlated with the class of MHC molecule engaged, and that some mechanism prevents mismatched intermediates from achieving full maturity.
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Affiliation(s)
- M Correia-Neves
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (CNRS / INSERM / ULP), Illkirch, C.U. de Strasbourg, France
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40
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Sosinowski T, Killeen N, Weiss A. The Src-like adaptor protein downregulates the T cell receptor on CD4+CD8+ thymocytes and regulates positive selection. Immunity 2001; 15:457-66. [PMID: 11567635 DOI: 10.1016/s1074-7613(01)00195-9] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In this report, we show that the Src-like adaptor protein (SLAP) plays an important role in thymocyte development. SLAP expression is developmentally regulated; it is low in CD4-CD8- thymocytes, it peaks in the CD4+CD8+ subset, and it decreases to low levels in more mature cells. Disruption of the SLAP gene leads to a marked upregulation of TCR and CD5 expression at the CD4+CD8+ stage. The absence of SLAP was also developmentally significant because it enhanced positive selection in mice expressing the DO11.10 transgenic T cell receptor. Moreover, SLAP deletion at least partially rescued the development of ZAP-70-deficient thymocytes. These results demonstrate that SLAP participates in a novel mechanism of TCR downregulation at the CD4+CD8+ stage and regulates positive selection.
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Affiliation(s)
- T Sosinowski
- Departments of Microbiology and Immunology, University of California at San Francisco, San Francisco, CA 94143, USA
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41
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Attuil V, Bucher P, Rossi M, Mutin M, Maryanski JL. Comparative T cell receptor repertoire selection by antigen after adoptive transfer: a glimpse at an antigen-specific preimmune repertoire. Proc Natl Acad Sci U S A 2000; 97:8473-8. [PMID: 10900008 PMCID: PMC26972 DOI: 10.1073/pnas.97.15.8473] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The low frequency of precursor cells specific for any particular antigen (Ag) makes it difficult to characterize preimmune T cell receptor (TCR) repertoires and to understand repertoire selection during an immune response. We have undertaken a combined adoptive transfer single-cell PCR approach to probe the Ag-specific preimmune repertoires of individual mice. Our strategy was to inject paired irradiated recipient mice with normal spleen cells prepared from individual donors and to compare the TCR repertoires subsequently selected during a CD8 response to a defined model Ag. We found that although some TCRs were shared, the TCR repertoires selected by mice receiving splenocytes from the same donor were not identical in terms of the TCRs selected and their relative frequencies. Our results together with computer simulations imply that individual mice express distinct Ag-specific preimmune TCR repertoires composed of expanded clones and that selection by Ag is a random process.
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Affiliation(s)
- V Attuil
- Institut National de la Santé et de la Recherche Médicale, Unit 503, Ecole Normale Supérieure de Lyon, 69007 Lyon, France
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42
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He YW, Beers C, Deftos ML, Ojala EW, Forbush KA, Bevan MJ. Down-regulation of the orphan nuclear receptor ROR gamma t is essential for T lymphocyte maturation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:5668-74. [PMID: 10820242 DOI: 10.4049/jimmunol.164.11.5668] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Thymocyte development is a tightly regulated process. CD4+CD8+ double-positive (DP) immature thymocytes exhibit distinct phenotypic features from mature T cells; they express only 10% of surface TCR that are found on mature T cells and do not proliferate and produce IL-2 in response to stimulation. In this report we show that transgenic expression of the orphan nuclear receptor ROR gamma t in mature T cells down-regulates their surface TCR expression. The ROR gamma t transgene inhibits IL-2 production by mature T cells, and this inhibition may be partially due to the inhibitory effect of ROR gamma t on c-Rel transcription. Furthermore, ectopic expression of ROR gamma t inhibits the proliferation of mature and immature T cells. These results, together with its predominant expression in DP thymocytes, suggest that ROR gamma t controls these distinct phenotypic features of DP thymocytes. Our data suggest that down-regulation of ROR gamma t expression in thymocytes is essential for their maturation.
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MESH Headings
- Animals
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Crosses, Genetic
- Down-Regulation/genetics
- Down-Regulation/immunology
- Fas Ligand Protein
- Gene Expression Regulation/immunology
- Immunosuppressive Agents/pharmacology
- Interleukin-2/antagonists & inhibitors
- Interleukin-2/biosynthesis
- Ligands
- Lymphocyte Activation/immunology
- Membrane Glycoproteins/biosynthesis
- Mice
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Mice, Transgenic
- Nuclear Receptor Subfamily 1, Group F, Member 3
- Proto-Oncogene Proteins c-rel/antagonists & inhibitors
- Proto-Oncogene Proteins c-rel/biosynthesis
- Receptors, Antigen, T-Cell/antagonists & inhibitors
- Receptors, Antigen, T-Cell/biosynthesis
- Receptors, Cytoplasmic and Nuclear/biosynthesis
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/physiology
- Receptors, Retinoic Acid
- Receptors, Thyroid Hormone
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
- Thymus Gland/cytology
- Thymus Gland/metabolism
- Transgenes/immunology
- Up-Regulation/genetics
- Up-Regulation/immunology
- fas Receptor/metabolism
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Affiliation(s)
- Y W He
- Department of Immunology and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
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43
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Itano A, Robey E. Highly efficient selection of CD4 and CD8 lineage thymocytes supports an instructive model of lineage commitment. Immunity 2000; 12:383-9. [PMID: 10795736 DOI: 10.1016/s1074-7613(00)80190-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We undertook a kinetic analysis of the generation of mature T cells in TCR and coreceptor transgenic mice using BrdU labeling. We observed that the selection efficiency of mature CD4-CD8+ and CD4+CD8- thymocytes could be as high as 40% and 90% of CD4+CD8+ precursors, respectively. The surprisingly high efficiency of selection favors an instructional model of lineage commitment and is incompatible with a stochastic model in which the efficiency of selection would be no greater than 100% in both lineages combined.
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Affiliation(s)
- A Itano
- Department of Molecular and Cell Biology, University of California, Berkeley 94720, USA
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44
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Abstract
In order to study the role of calcium/calmodulin kinase II (CaMKII) in T cells, we generated transgenic mice expressing CaMKIIgammaB* (T287D), a partially calcium-independent mutant of CaMKIIgammaB. In these mice, the size of the thymus was increased 1.5- to 2-fold, at least in part due to an increase in the lifespan of double-positive (DP) thymocytes. More importantly, there was an increase in the number of T cells in the secondary lymphoid organs that had acquired an antigen-dependent memory phenotype. These T cells were bonafide memory cells as assessed by a variety of criteria. In addition, T cells from wild-type mice acquired calcium-independent CaMKII activity after several rounds of antigen-stimulated division. We propose that CaMKII controls a distinct process of activation-induced cellular differentiation.
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Affiliation(s)
- J D Bui
- Department of Biology and Cancer Center, University of California, San Diego, La Jolla 92093-0687, USA
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45
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Imachi H, Murao K, Hiramine C, Sayo Y, Sato M, Hosokawa H, Ishida T, Kodama T, Quehenberger O, Steinberg D, Takahara J. Human scavenger receptor B1 is involved in recognition of apoptotic thymocytes by thymic nurse cells. J Transl Med 2000; 80:263-70. [PMID: 10701695 DOI: 10.1038/labinvest.3780029] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Recognition and uptake of apoptotic cells by neighboring phagocytes is essential for the clearance of dying cells without accompanying inflammation or tissue damage. In the thymus, many apoptotic cells are generated in the process of negative selection, and both thymic macrophages (professional phagocytes) and nursing thymic epithelial cells (nursing TEC; nonprofessional phagocytes) recognize and ingest them. However the receptors responsible for this recognition and uptake have not been identified. In the present study, we have established a human nursing TEC line and examined the expression of several genes of the scavenger receptor family considered to be potential receptors for apoptotic cells. Human scavenger receptor-B1 (hSR-B1)/CLA-1, previously shown to recognize apoptotic cells, was strongly expressed in nursing TEC, whereas there was little or no expression of the other scavenger receptors tested: scavenger receptor class A, CD36, or CD68. Suppression of hSR-B1/CLA-1 expression using antisense oligonucleotides decreased the binding of apoptotic thymocytes to nursing TEC by more than 40%. These results indicate that hSR-B1/CLA-1 may play a major role in the clearance of apoptotic cells in the thymus, mediating the recognition and ingestion of apoptotic thymocytes by nursing TEC.
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Affiliation(s)
- H Imachi
- First Department of Internal Medicine, Kagawa Medical University, Japan.
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46
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Detours V, Mehr R, Perelson AS. Deriving quantitative constraints on T cell selection from data on the mature T cell repertoire. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:121-8. [PMID: 10605002 DOI: 10.4049/jimmunol.164.1.121] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The T cell repertoire is shaped in the thymus through positive and negative selection. Thus, data about the mature repertoire may be used to infer information on how TCR generation and selection operate. Assuming that T cell selection is affinity driven, we derive the quantitative constraints that the parameters driving these processes must fulfill to account for the experimentally observed levels of alloreactivity, self MHC restriction and the frequency of cells recognizing a given foreign Ag. We find that affinity-driven selection is compatible with experimental estimates of these latter quantities only if 1) TCRs see more peptide residues than MHC polymorphic residues, 2) the majority of positively selected clones are deleted by negative selection, 3) between 1 and 3.6 clonal divisions occur on average in the thymus after completion of TCR rearrangement, and 4) selection is driven by 103-105 self peptides.
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Affiliation(s)
- V Detours
- Theoretical Biology and Biophysics, Center for Nonlinear Studies, Los Alamos National Laboratory, NM 87545, USA
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47
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Detours V, Mehr R, Perelson AS. A quantitative theory of affinity-driven T cell repertoire selection. J Theor Biol 1999; 200:389-403. [PMID: 10525398 DOI: 10.1006/jtbi.1999.1003] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Binding of the T cell antigen receptor (TCR) to peptides presented on molecules encoded by major histocompatibility complex (MHC) genes is the key event driving T cell development and activation. Selection of the T cell repertoire in the thymus involves two steps. First, positive selection promotes the survival of cells binding thymic self-MHC-peptide complexes with sufficient affinity. The resulting repertoire is self-MHC restricted: it recognizes foreign peptides presented on self, but not foreign MHC. Second, negative selection deletes cells which may be potentially harmful because their receptors interact with self-MHC-peptide complexes with too high an affinity. The mature repertoire is also highly alloreactive: a large fraction of T cells respond to tissues harboring foreign MHC. We derive mathematical expressions giving the frequency of alloreactivity, the level of self-MHC restriction, and the fraction of the repertoire activated by a foreign peptide, as a function of the parameters driving the generation and selection of the repertoire: self-MHC and self-peptide diversity, the stringencies of positive and negative selection, and the number of peptide and MHC polymorphic residues that contribute to T cell receptor binding. Although the model is based on a simplified digit string representation of receptors, all the parameters but one relate directly to experimentally determined quantities. The only parameter without a biological counterpart has no effect on the model's behavior besides a trivial and easily preventable discretization effect. We further analyse the role of the MHC and peptide contribution to TCR binding, and find that their relative, rather than absolute value, is important in shaping the mature repertoire. This result makes it possible to adopt different physical interpretations for the digit string formalism. We also find that the alloreactivity level can be inferred directly from data on the stringency of selection, and that, in agreement with recent experiments, it is not affected by thymic selection.
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Affiliation(s)
- V Detours
- Los Alamos National Laboratory, Theoretical Biology and Biophysics, MS K710, Los Alamos, NM, 87545, USA
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48
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Ge Q, Chen WF. Phenotypic identification of the subgroups of murine T-cell receptor alphabeta+ CD4+ CD8- thymocytes and its implication in the late stage of thymocyte development. Immunology 1999; 97:665-71. [PMID: 10457221 PMCID: PMC2326876 DOI: 10.1046/j.1365-2567.1999.00816.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phenotypic analysis of the medullary-type CD4+ CD8- [CD4 single-positive (SP)] thymocytes has revealed phenotypic heterogeneity within this cell population. The characteristic phenotype of mature peripheral T cells can be uniquely marked as Qa-2+ HSA- CD69-, whereas in the medullary-type CD4 SP thymocytes, the expression patterns of many markers were quite different. This suggests that there are many subgroups in the population, which reflects that medullary-type CD4 SP thymocytes may undergo phenotypic maturation. According to the results of two-colour flow cytometry, seven discrete phenotypes were identified by the expression capacity of Qa-2, HSA, CD69, 3G11 and 6C10 molecules. Consequently, the phenotypic precursor-progeny relationship can be envisaged as: 3G11- 6C10+ CD69+ HSAhi -->3G11+ 6C10+ CD69+ HSAhi --> 3G11+ 6C10- CD69+ HSAint -->3G11+ 6C10- CD69- HSAint Qa-2- -->3G11+ HSA-/lo Qa-2lo. At the stage of 3G11+ 6C10- CD69- HSAint Qa-2-, a branch pathway could be initiated, which gave rise to 3G11- HSAl degrees Qa-2- cells, which then, in turn, developed into 3G11- HSA-/loQa-2hi cells, a minor subgroup of the most mature CD4 SP cells. Consistent with this predicted pathway, experiments indicated that the first two subgroups were still cortisone sensitive, whereas the others were cortisone resistant. The cells in the last two Qa-2-positive subgroups are probably ready for emigration into the periphery.
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Affiliation(s)
- Q Ge
- Department of Immunology, Beijing Medical University, Beijing, China
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Vacchio MS, Lee JYM, Ashwell JD. Thymus-Derived Glucocorticoids Set the Thresholds for Thymocyte Selection by Inhibiting TCR-Mediated Thymocyte Activation. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.163.3.1327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Selection processes in the thymus eliminate nonfunctional or harmful T cells and allow the survival of those cells with the potential to recognize Ag in association with self-MHC-encoded molecules (Ag/MHC). We have previously demonstrated that thymus-derived glucocorticoids antagonize TCR-mediated deletion, suggesting a role for endogenous thymic glucocorticoids in promoting survival of thymocytes following TCR engagement. Consistent with this hypothesis, we now show that inhibition of thymus glucocorticoid biosynthesis causes an increase in thymocyte apoptosis and a decrease in recovery that are directly proportional to the number of MHC-encoded molecules present and, therefore, the number of ligands available for TCR recognition. Expression of CD5 on CD4+CD8+ thymocytes, an indicator of TCR-mediated activation, increased in a TCR- and MHC-dependent manner when corticosteroid production or responsiveness was decreased. These results indicate that thymus-derived glucocorticoids determine where the window of thymocyte selection occurs in the TCR avidity spectrum by dampening the biological consequences of TCR occupancy and reveal that glucocorticoids mask the high percentage of self-Ag/MHC-reactive thymocytes that exist in the preselection repertoire.
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Affiliation(s)
| | | | - Jonathan D. Ashwell
- †Laboratory of Immune Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
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Baldwin KK, Trenchak BP, Altman JD, Davis3 MM. Negative Selection of T Cells Occurs Throughout Thymic Development. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.163.2.689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Thymic positive and negative selections govern the development of a self-MHC-reactive, yet self-tolerant, T cell repertoire. Whether these processes occur independently or sequentially remains controversial. To investigate these issues, we have employed tetrameric peptide-MHC complexes to fluorescently label and monitor polyclonal populations of thymocytes that are specific for moth cytochrome c (MCC)/I-Ek. In TCR β mice tetramer-positive thymocytes are detectable even in the most immature TCR-expressing cells. In the presence of MCC peptide, thymocytes that bind strongly to MCC/I-Ek tetramers are deleted earlier in development and more extensively than cells that bind weakly. This negative selection of the MCC/I-Ek-specific cells occurs continuously throughout development and before any evidence of positive selection. Thus, positive and negative selections are independent processes that need not occur sequentially.
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Affiliation(s)
| | - Brian P. Trenchak
- †Department of Microbiology and Immunology, and
- ‡Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305; and
| | - John D. Altman
- §Department of Microbiology and Immunology, Emory University, Atlanta, GA 30322
| | - Mark M. Davis3
- †Department of Microbiology and Immunology, and
- ‡Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305; and
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