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Abstract
T cell development is a complex multistep process that requires the coordinated activation of distinct signaling responses and the regulated progression of developing cells (thymocytes) through key stages of maturation. Although sophisticated techniques such as fetal thymus organ culture, in vitro thymocyte culture, and multiparameter flow cytometry-based cell sorting are now widely employed to evaluate thymocyte maturation by experienced laboratories, defects in T cell development can usually be identified with relatively simple flow cytometry screening methods. Here, we provide a basic protocol for assessment of T cell development that will enable laboratories with access to a multi-laser flow cytometer to screen mouse strains, including those generated from embryonic stem cells with targeted gene mutations, for thymocyte maturation defects.
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Affiliation(s)
- Jan Y M Lee
- Section on Hematopoiesis and Lymphocyte Biology, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Paul E Love
- Section on Hematopoiesis and Lymphocyte Biology, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
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2
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The actin remodeling protein cofilin is crucial for thymic αβ but not γδ T-cell development. PLoS Biol 2018; 16:e2005380. [PMID: 29985916 PMCID: PMC6053251 DOI: 10.1371/journal.pbio.2005380] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 07/19/2018] [Accepted: 06/22/2018] [Indexed: 12/16/2022] Open
Abstract
Cofilin is an essential actin remodeling protein promoting depolymerization and severing of actin filaments. To address the relevance of cofilin for the development and function of T cells in vivo, we generated knock-in mice in which T-cell-specific nonfunctional (nf) cofilin was expressed instead of wild-type (WT) cofilin. Nf cofilin mice lacked peripheral αβ T cells and showed a severe thymus atrophy. This was caused by an early developmental arrest of thymocytes at the double negative (DN) stage. Importantly, even though DN thymocytes expressed the TCRβ chain intracellularly, they completely lacked TCRβ surface expression. In contrast, nf cofilin mice possessed normal numbers of γδ T cells. Their functionality was confirmed in the γδ T-cell-driven, imiquimod (IMQ)-induced, psoriasis-like murine model. Overall, this study not only highlights the importance of cofilin for early αβ T-cell development but also shows for the first time that an actin-binding protein is differentially involved in αβ versus γδ T-cell development.
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3
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LAT alleviates Th2/Treg imbalance in an OVA-induced allergic asthma mouse model through LAT-PLC-γ1 interaction. Int Immunopharmacol 2017; 44:9-15. [PMID: 28063403 DOI: 10.1016/j.intimp.2016.12.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 12/19/2016] [Accepted: 12/22/2016] [Indexed: 11/23/2022]
Abstract
INTRODUCTION Low expression of linker for activation of T cells (LAT) is observed in asthma. LAT and its downstream regulator, phospholipase C-gamma 1 (PLC-γ1) play important roles in the T cell antigen receptor signaling pathway, and their interaction is associated with CD4+ cell polarization. Here, we investigated whether LAT can alleviate the imbalance among CD4+ cell subgroups and the possible mechanism. METHODS An ovalbumin-induced allergic asthma mouse model was established and LAT plasmid was delivered. The pathological changes in lung were evaluated by hematoxylin and eosin and periodic acid-Schiff staining. The typical cytokines released by T helper 2 (Th2) and regulatory T (Treg) cells were measured using enzyme-linked immunosorbent assay and the number of Th1, Th2, and Treg cells were determined using flow cytometry. Lung CD4+ T cells were isolated by magnetic isolation. The mRNA expression of LAT and PLC-γ1 was determined by real-time PCR. Co-Immunoprecipitation was performed to confirm the interaction between LAT and PLC-γ1. The protein expression of LAT, PLC-γ1 and corresponding downstream signaling factors were determined by western blotting. RESULTS The delivery of LAT DNA to the lung could suppress an overactive Th2 response by decreasing allergic response and Th2 cytokine secretion, and by increasing Treg cytokine secretion. The Th2/Treg imbalance in lung and decreased phosphorylated PLC-γ1 expression in lung CD4+ T cells were rectified by LAT DNA delivery. Excessive activation of the Raf-MEK-ERK and PI3K-AKT-CREB pathways after asthma is attenuated by LAT. CONCLUSION The site-specific delivery of LAT DNA to the lung could suppress an overactive Th2 response and rectify the Th2/Treg imbalance in asthmatic mouse model. LAT-PLC-γ1 interaction may contribute to LAT activity in vivo and LAT protects against asthma partly via Raf-MEK-ERK and PI3K-AKT-CREB pathways. The delivery of LAT DNA could offer a novel and safe strategy for asthma prevention.
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4
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Abstract
T cell development is a complex multistep process that requires the coordinated activation of distinct signaling responses and the regulated progression of developing cells (thymocytes) through key stages of maturation. Although sophisticated techniques such as fetal thymus organ culture, in vitro thymocyte culture, and multi-parameter flow cytometric analysis are now widely employed to evaluate thymocyte maturation by experienced laboratories, defects in T cell development can usually be identified with more simplified screening methods. Here, we provide a basic protocol for assessment of T cell development that will enable laboratories with access to a four parameter flow cytometer to screen mouse strains, including those generated from embryonic stem cells with targeted gene mutations, for thymocyte maturation defects.
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Affiliation(s)
- Jan Y M Lee
- Section for Cellular and Developmental Biology, Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA
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5
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Hathcock KS, Farrington L, Ivanova I, Livak F, Selimyan R, Sen R, Williams J, Tai X, Hodes RJ. The requirement for pre-TCR during thymic differentiation enforces a developmental pause that is essential for V-DJβ rearrangement. PLoS One 2011; 6:e20639. [PMID: 21673984 PMCID: PMC3108609 DOI: 10.1371/journal.pone.0020639] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 05/06/2011] [Indexed: 01/26/2023] Open
Abstract
T cell development occurs in the thymus and is critically dependent on productive TCRβ rearrangement and pre-TCR expression in DN3 cells. The requirement for pre-TCR expression results in the arrest of thymocytes at the DN3 stage (β checkpoint), which is uniquely permissive for V-DJβ recombination; only cells expressing pre-TCR survive and develop beyond the DN3 stage. In addition, the requirement for TCRβ rearrangement and pre-TCR expression enforces suppression of TCRβ rearrangement on a second allele, allelic exclusion, thus ensuring that each T cell expresses only a single TCRβ product. However, it is not known whether pre-TCR expression is essential for allelic exclusion or alternatively if allelic exclusion is enforced by developmental changes that can occur in the absence of pre-TCR. We asked if thymocytes that were differentiated without pre-TCR expression, and therefore without pause at the β checkpoint, would suppress all V-DJβ rearrangement. We previously reported that premature CD28 signaling in murine CD4(-)CD8(-) (DN) thymocytes supports differentiation of CD4(+)CD8(+) (DP) cells in the absence of pre-TCR expression. The present study uses this model to define requirements for TCRβ rearrangement and allelic exclusion. We demonstrate that if cells exit the DN3 developmental stage before TCRβ rearrangement occurs, V-DJβ rearrangement never occurs, even in DP cells that are permissive for D-Jβ and TCRα rearrangement. These results demonstrate that pre-TCR expression is not essential for thymic differentiation to DP cells or for V-DJβ suppression. However, the requirement for pre-TCR signals and the exclusion of alternative stimuli such as CD28 enforce a developmental "pause" in early DN3 cells that is essential for productive TCRβ rearrangement to occur.
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MESH Headings
- Animals
- B7-2 Antigen/genetics
- B7-2 Antigen/metabolism
- CD28 Antigens/genetics
- CD28 Antigens/metabolism
- Cell Differentiation
- DNA-Binding Proteins/metabolism
- Gene Expression Regulation/immunology
- Gene Rearrangement, alpha-Chain T-Cell Antigen Receptor
- Gene Rearrangement, beta-Chain T-Cell Antigen Receptor
- Histones/chemistry
- Histones/metabolism
- Lysine
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/metabolism
- Methylation
- Mice
- Mice, Transgenic
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- T-Lymphocytes/cytology
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
- Thymus Gland/cytology
- Thymus Gland/metabolism
- Transcription, Genetic/immunology
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Affiliation(s)
- Karen S Hathcock
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
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6
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Chuck MI, Zhu M, Shen S, Zhang W. The role of the LAT-PLC-gamma1 interaction in T regulatory cell function. THE JOURNAL OF IMMUNOLOGY 2010; 184:2476-86. [PMID: 20130215 DOI: 10.4049/jimmunol.0902876] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The interaction between the linker for activation of T cells (LAT) with PLC-gamma1 is important for TCR-mediated Ca(2+) signaling and MAPK activation. Knock-in mice harboring a mutation at the PLC-gamma1 binding site (Y136) of LAT develop a severe lymphoproliferative syndrome. These mice have defective thymic development and selection and lack natural regulatory T cells, implicating a breakdown of both central and peripheral tolerance. To bypass this developmental defect, we developed a conditional knock-in line in which only LATY136F is expressed in mature T cells after deletion of the wild type LAT allele. Analysis of LATY136F T cells indicated that the interaction between LAT and PLC-gamma1 plays an important role in TCR-mediated signaling, proliferation, and IL-2 production. Furthermore, the deletion of LAT induced development of the lymphoproliferative syndrome in these mice. Although Foxp3(+) natural Treg cells were present in these mice after deletion, they were unable to suppress the proliferation of conventional T cells. Our data indicate that the binding of LAT to PLC-gamma1 is essential for the suppressive function of CD4(+)CD25(+) regulatory T cells.
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Affiliation(s)
- Mariana I Chuck
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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7
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Roberts JL, Lauritsen JPH, Cooney M, Parrott RE, Sajaroff EO, Win CM, Keller MD, Carpenter JH, Carabana J, Krangel MS, Sarzotti M, Zhong XP, Wiest DL, Buckley RH. T-B+NK+ severe combined immunodeficiency caused by complete deficiency of the CD3zeta subunit of the T-cell antigen receptor complex. Blood 2007; 109:3198-206. [PMID: 17170122 PMCID: PMC1852234 DOI: 10.1182/blood-2006-08-043166] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2006] [Accepted: 12/05/2006] [Indexed: 01/14/2023] Open
Abstract
CD3zeta is a subunit of the T-cell antigen receptor (TCR) complex required for its assembly and surface expression that also plays an important role in TCR-mediated signal transduction. We report here a patient with T(-)B(+)NK(+) severe combined immunodeficiency (SCID) who was homozygous for a single C insertion following nucleotide 411 in exon 7 of the CD3zeta gene. The few T cells present contained no detectable CD3zeta protein, expressed low levels of cell surface CD3epsilon, and were nonfunctional. CD4(+)CD8(-)CD3epsilon(low), CD4(-)CD8(+)CD3epsilon(low), and CD4(-)CD8(-)CD3epsilon(low) cells were detected in the periphery, and the patient also exhibited an unusual population of CD56(-)CD16(+) NK cells with diminished cytolytic activity. Additional studies demonstrated that retrovirally transduced patient mutant CD3zeta cDNA failed to rescue assembly of nascent complete TCR complexes or surface TCR expression in CD3zeta-deficient MA5.8 murine T-cell hybridoma cells. Nascent transduced mutant CD3zeta protein was also not detected in metabolically labeled MA5.8 cells, suggesting that it was unstable and rapidly degraded. Taken together, these findings provide the first demonstration that complete CD3zeta deficiency in humans can cause SCID by preventing normal TCR assembly and surface expression.
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Affiliation(s)
- Joseph L Roberts
- Department of Pediatrics and Immunology, Duke University Medical Center, Durham, NC 27710, USA.
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8
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Abstract
The many immunological observations and results from in-vitro or in-vivo experiments vary, and their interpretations differ enormously. A major problem is that within a normal distribution of biological phenomena, which are measurable with many methods, virtually anything is possible. Within a coevolutionary context, the definition of biologically relevant thresholds is an important key to improve our understanding of weaknesses and strengths of the immune system. This review is a personal view, comparing textbook rules and experiments using model antigens with observations on immunity against infections or tumors to critically evaluate our perception and understanding of specificity, affinity maturation, antigen presentation, selection of the class of the immune response, immunological memory and protective immunity, positive selection of T cells and self/nonself discrimination.
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Affiliation(s)
- Rolf M Zinkernagel
- Institute for Experimental Immunology, University Hospital, Zurich, Switzerland.
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Sommers CL, Park CS, Lee J, Feng C, Fuller CL, Grinberg A, Hildebrand JA, Lacaná E, Menon RK, Shores EW, Samelson LE, Love PE. A LAT mutation that inhibits T cell development yet induces lymphoproliferation. Science 2002; 296:2040-3. [PMID: 12065840 DOI: 10.1126/science.1069066] [Citation(s) in RCA: 232] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Mice homozygous for a single tyrosine mutation in LAT (linker for activation of T cells) exhibited an early block in T cell maturation but later developed a polyclonal lymphoproliferative disorder and signs of autoimmune disease. T cell antigen receptor (TCR)-induced activation of phospholipase C-gamma1 (PLC-gamma1) and of nuclear factor of activated T cells, calcium influx, interleukin-2 production, and cell death were reduced or abrogated in T cells from LAT mutant mice. In contrast, TCR-induced Erk activation was intact. These results identify a critical role for integrated PLC-gamma1 and Ras-Erk signaling through LAT in T cell development and homeostasis.
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Affiliation(s)
- Connie L Sommers
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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10
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Sant'Angelo DB, Cresswell P, Janeway CA, Denzin LK. Maintenance of TCR clonality in T cells expressing genes for two TCR heterodimers. Proc Natl Acad Sci U S A 2001; 98:6824-9. [PMID: 11381132 PMCID: PMC34437 DOI: 10.1073/pnas.121179998] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/11/2001] [Indexed: 11/18/2022] Open
Abstract
T cell receptor (TCR) allelic exclusion is believed to be primarily mediated by suppression of further recombination at the TCR locus after the expression of a functional TCR protein. Genetic allelic exclusion has been shown to be leaky for the beta chain and, more commonly, for the alpha chain. Here, we demonstrate an additional mechanism by which T cells can maintain monoclonality. T cells from double TCR transgenic mice express only one or the other of the two available TCRs at the cell surface. This "functional allelic exclusion" is apparently due to control of the TCR assembly process because these T cells express RNA and protein for all four transgenic TCR proteins. Lack of cell surface expression of the second TCR may be controlled by a failure to assemble the TCR heterodimer.
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MESH Headings
- Alleles
- Dimerization
- Flow Cytometry
- Humans
- RNA, Messenger/analysis
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/physiology
- Reverse Transcriptase Polymerase Chain Reaction
- T-Lymphocytes/metabolism
- Transgenes
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Affiliation(s)
- D B Sant'Angelo
- Immunology Program, Memorial Sloan-Kettering Cancer Center, Weill Graduate School of Medical Sciences of Cornell University, New York, NY 10021, USA. d-sant'
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11
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Brabb T, Rubicz R, Mannikko V, Goverman J. Separately expressed T cell receptor alpha and beta chain transgenes exert opposite effects on T cell differentiation and neoplastic transformation. Eur J Immunol 1997; 27:3039-48. [PMID: 9394835 DOI: 10.1002/eji.1830271142] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Two aspects of T cell differentiation in T cell receptor (TCR)-transgenic mice, the generation of an unusual population of CD4-CD8-TCR+ thymocytes and the absence of gamma delta cells, have been the focus of extensive investigation. To examine the basis for these phenomena, we investigated the effects of separate expression of a transgenic TCR alpha chain and a transgenic TCR beta chain on thymocyte differentiation. Our data indicate that expression of a transgenic TCR alpha chain causes thymocytes to differentiate into a CD4-CD8-TCR+ lineage at an early developmental stage, depleting the number of thymocytes that differentiate into the alpha beta lineage. Surprisingly, expression of the TCR alpha chain transgene is also associated with the development of T cell lymphosarcoma. In contrast, expression of the transgenic TCR beta chain causes immature T cells to accelerate differentiation into the alpha beta lineage and thus inhibits the generation of gamma delta cells. Our observations provide a model for understanding T cell differentiation in TCR-transgenic mice.
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MESH Headings
- Animals
- CD4 Antigens/analysis
- CD8 Antigens/analysis
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/immunology
- Cell Transformation, Neoplastic/metabolism
- Embryonic and Fetal Development/genetics
- Embryonic and Fetal Development/immunology
- Gene Expression Regulation/immunology
- Genes, T-Cell Receptor alpha/immunology
- Genes, T-Cell Receptor beta/immunology
- Lymphocyte Count
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/physiology
- Lymphoma, Non-Hodgkin/genetics
- Lymphoma, Non-Hodgkin/immunology
- Lymphoma, T-Cell/genetics
- Lymphoma, T-Cell/immunology
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Receptors, Antigen, T-Cell, alpha-beta/biosynthesis
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, gamma-delta/biosynthesis
- Signal Transduction/genetics
- Signal Transduction/immunology
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/metabolism
- T-Lymphocyte Subsets/pathology
- Transgenes/immunology
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Affiliation(s)
- T Brabb
- Department of Molecular Biotechnology, University of Washington, Seattle 98195, USA
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12
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O'Shea CC, Thornell AP, Rosewell IR, Hayes B, Owen MJ. Exit of the pre-TCR from the ER/cis-Golgi is necessary for signaling differentiation, proliferation, and allelic exclusion in immature thymocytes. Immunity 1997; 7:591-9. [PMID: 9390683 DOI: 10.1016/s1074-7613(00)80380-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A major issue is whether surface expression of the pre-TCR is necessary for signaling the development of immature thymocytes. To address this question, we generated transgenic mice expressing a TCRbeta chain that had a strong endoplasmic reticulum (ER) retrieval signal (TCRbetaER) and that was expressed intracellularly but failed to reach the cell surface. In TCRbetaER transgenic mice, there was a failure of allelic exclusion. Also, the transgene failed to rescue the developmental defects observed in TCRbeta-null mice. In contrast, TCRbeta transgenes with a mutant ER retrieval sequence or lacking this sequence signaled efficient allelic exclusion and suppressed the TCRbeta-/- defect. These data show that exit of the pre-TCR from the ER/cis-Golgi is required for progression through the double-negative thymocyte checkpoint.
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MESH Headings
- Alleles
- Amino Acid Sequence
- Animals
- Calcium/metabolism
- Cell Differentiation
- Cell Division
- Endoplasmic Reticulum, Rough/metabolism
- Gene Expression Regulation, Developmental
- Gene Rearrangement, beta-Chain T-Cell Antigen Receptor
- Golgi Apparatus/metabolism
- Humans
- Mice
- Mice, Transgenic
- Molecular Sequence Data
- Protein Processing, Post-Translational
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- T-Lymphocytes/cytology
- Thymus Gland/cytology
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Affiliation(s)
- C C O'Shea
- Imperial Cancer Research Fund, Lincoln's Inn Fields, London, United Kingdom
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13
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Abstract
Current data suggest that an important function of the multimeric structure of the TCR is to enable the assembly of structurally and functionally different forms of the TCR, the pre-TCR and alphabetaTCR complexes, at different stages in development. Four distinct TCR subunits (the CD3gamma, delta, and epsilon chains and the zeta chain) contain signal transducing motifs; however, the zeta chain is notable for containing three of these elements. These motifs, especially those within the zeta chain, function to amplify signals generated by the TCR, and this property is especially critical during thymocyte selection. The results of several recent experiments argue that positive and negative selection of thymocytes may involve activation of distinct downstream signaling pathways. The outcome of thymocyte selection can also be influenced, however, by quantitative effects such as changes in ligand concentration or direct alteration of the TCR signaling potential. Recent studies pertaining to the kinetics of TCR-ligand interactions may provide insight into how signaling through the TCR can be regulated either quantitatively or qualitatively.
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Affiliation(s)
- E W Shores
- Division of Hematologic Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA
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14
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Wang B, Simpson SJ, Holländer GA, Terhorst C. Development and function of T lymphocytes and natural killer cells after bone marrow transplantation of severely immunodeficient mice. Immunol Rev 1997; 157:53-60. [PMID: 9255621 DOI: 10.1111/j.1600-065x.1997.tb00973.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Bone marrow (BM) transplantation experiments were performed in a strain of CD3 epsilon-transgenic mice, termed tg epsilon 26, which are completely deficient in T-cell and natural killer (NK) cell development. We found that an interaction of stromal cells and prothymocytes is required for the induction of a cortical thymic microenvironment. This induction takes place in a time window from fetal development to early neonates. Although the thymic environment is not required for NK-cell development, we found that aberrantly educated alpha beta or gamma delta T lymphocytes can influence NK-cell ontogeny. Surprisingly, BM transplantation of tg epsilon 26 fetuses and neonates results in normal T-cell development, but very low levels of NK cells. The poor NK-cell reconstitution in fetal and neonatal stages could be explained by an inefficient migration of hematopoietic progenitor cells to the BM. By contrast, migration of the progenitor cells to the thymus was efficient to initiate T-cell development. BM transplantation of adult tg epsilon 26 mice resulted in abnormal T-cell development which, in turn, caused an inflammatory bowel disease (IBD) in the recipient mice. Studies in these BM chimeras have revealed that both alpha beta and gamma delta T cells can be pathogenic and, further, that Th1-like cytokines produced by these cells are causal factors in the pathogenesis of IBD.
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Affiliation(s)
- B Wang
- Division of Immunology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachussetts 02215, USA.
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