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Abstract
Protein kinase Cη (PKCη) is a member of the novel PKC subfamily, which also includes δ, ε, and θ isoforms. Compared to the other novel PKCs, the function of PKCη in the immune system is largely unknown. Several studies have started to reveal the role of PKCη, particularly in T cells. PKCη is highly expressed in T cells, and is upregulated during thymocyte positive selection. Interestingly, like the θ isoform, PKCη is also recruited to the immunological synapse that is formed between a T cell and an antigen-presenting cell. However, unlike PKCθ, which becomes concentrated to the central region of the synapse, PKCη remains in a diffuse pattern over the whole area of the synapse, suggesting distinctive roles of these two isoforms in signal transduction. Although PKCη is dispensable for thymocyte development, further analysis of PKCη- or PKCθ-deficient and double-knockout mice revealed the redundancy of these two isoforms in thymocyte development. In contrast, PKCη rather than PKCθ, plays an important role for T cell homeostatic proliferation, which requires recognition of self-antigen. Another piece of evidence demonstrating that PKCη and PKCθ have isoform-specific as well as redundant roles come from the analysis of CD4 to CD8 T cell ratios in the periphery of these knockout mice. Deficiency in PKCη or PKCθ had opposing effects as PKCη knockout mice had a higher ratio of CD4 to CD8 T cells compared to that of wild-type mice, whereas PKCθ-deficient mice had a lower ratio. Biochemical studies showed that calcium flux and NFκB translocation is impaired in PKCη-deficient T cells upon TCR crosslinking stimulation, a character shared with PKCθ-deficient T cells. However, unlike the case with PKCθ, the mechanistic study of PKCη is at early stage and the signaling pathways involving PKCη, at least in T cells, are essentially unknown. In this review, we will cover the topics mentioned above as well as provide some perspectives for further investigations regarding PKCη.
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Affiliation(s)
- Guo Fu
- Department of Immunology and Microbial Science, The Scripps Research Institute La Jolla, CA, USA
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53
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Abstract
Recent data with CD8+ T cells show that the initial phase of T cell receptor (TCR) binding to MHC–peptide (MHCp) is quickly followed by a second, stronger, binding phase representing the binding of CD8 to the MHCp. This second phase requires signaling by a Src-family kinase such as Lck. These data point out two aspects of the initial stage of TCR signaling that have not yet been clearly resolved. Firstly, how and by which Src-family kinase, is the initial phosphorylation of CD3ζ accomplished, given that the Lck associated with the co-receptors (CD4 or CD8) is not yet available. Secondly, what is the mechanism by which the co-receptor is brought close to the bound TCR before the co-receptor binds to MHCp?
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Affiliation(s)
- Nicholas R J Gascoigne
- Department of Immunology and Microbial Science, The Scripps Research Institute La Jolla, CA, USA.
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54
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Fu G, Hu J, Niederberger-Magnenat N, Rybakin V, Casas J, Yachi PP, Feldstein S, Ma B, Hoerter JAH, Ampudia J, Rigaud S, Lambolez F, Gavin AL, Sauer K, Cheroutre H, Gascoigne NRJ. Protein kinase C η is required for T cell activation and homeostatic proliferation. Sci Signal 2011; 4:ra84. [PMID: 22155788 DOI: 10.1126/scisignal.2002058] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Protein kinase C η (PKCη) is abundant in T cells and is recruited to the immunological synapse that is formed between a T cell and an antigen-presenting cell; however, its function in T cells is unknown. We showed that PKCη was required for the activation of mature CD8+ T cells through the T cell receptor. Compared with wild-type T cells, PKCη-/- T cells showed poor proliferation in response to antigen stimulation, a trait shared with T cells deficient in PKCθ, which is the most abundant PKC isoform in T cells and was thought to be the only PKC isoform with a specific role in T cell activation. In contrast, only PKCη-deficient T cells showed defective homeostatic proliferation, which requires self-antigen recognition. PKCη was dispensable for thymocyte development; however, thymocytes from mice doubly deficient in PKCη and PKCθ exhibited poor development, indicating some redundancy between the PKC isoforms. Deficiency in PKCη or PKCθ had opposing effects on the relative numbers of CD4+ and CD8+ T cells. PKCη-/- mice had a higher ratio of CD4+ to CD8+ T cells compared to that of wild-type mice, whereas PKCθ-/- mice had a lower ratio. Mice deficient in both isoforms exhibited normal cell ratios. Together, these data suggest that PKCη shares some redundant roles with PKCθ in T cell biology and also performs nonredundant functions that are required for T cell homeostasis and activation.
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Affiliation(s)
- Guo Fu
- Department of Immunology and Microbial Science, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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55
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Abstract
A T cell receptor (TCR) that binds both major histocompatibility complex (MHC) class I and class II molecules reveals a novel structural variation that can potentially allow a single TCR to have three widely differing binding sites (Yin et al., 2011).
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Affiliation(s)
- Nicholas R J Gascoigne
- Department of Immunology and Microbial Science, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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56
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Brockmeyer C, Paster W, Pepper D, Tan CP, Trudgian DC, McGowan S, Fu G, Gascoigne NRJ, Acuto O, Salek M. T cell receptor (TCR)-induced tyrosine phosphorylation dynamics identifies THEMIS as a new TCR signalosome component. J Biol Chem 2011; 286:7535-47. [PMID: 21189249 PMCID: PMC3045008 DOI: 10.1074/jbc.m110.201236] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2010] [Revised: 12/06/2010] [Indexed: 11/24/2022] Open
Abstract
Stimulation of the T cell antigen receptor (TCR) induces formation of a phosphorylation-dependent signaling network via multiprotein complexes, whose compositions and dynamics are incompletely understood. Using stable isotope labeling by amino acids in cell culture (SILAC)-based quantitative proteomics, we investigated the kinetics of signal propagation after TCR-induced protein tyrosine phosphorylation. We confidently assigned 77 proteins (of 758 identified) as a direct or indirect consequence of tyrosine phosphorylation that proceeds in successive "signaling waves" revealing the temporal pace at which tyrosine kinases activate cellular functions. The first wave includes thymocyte-expressed molecule involved in selection (THEMIS), a protein recently implicated in thymocyte development but whose signaling role is unclear. We found that tyrosine phosphorylation of THEMIS depends on the presence of the scaffold proteins Linker for activation of T cells (LAT) and SH2 domain-containing lymphocyte protein of 76 kDa (SLP-76). THEMIS associates with LAT, presumably via the adapter growth factor receptor-bound protein 2 (Grb2) and with phospholipase Cγ1 (PLC-γ1). RNAi-mediated THEMIS knock-down inhibited TCR-induced IL-2 gene expression due to reduced ERK and nuclear factor of activated T cells (NFAT)/activator protein 1 (AP-1) signaling, whereas JNK, p38, or nuclear factor κB (NF-κB) activation were unaffected. Our study reveals the dynamics of TCR-dependent signaling networks and suggests a specific role for THEMIS in early TCR signalosome function.
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Affiliation(s)
| | | | | | | | - David C. Trudgian
- Proteomics Facility, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, United Kingdom
| | - Simon McGowan
- the Computational Biology Research Group, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS, United Kingdom, and
| | - Guo Fu
- the Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California 92037
| | - Nicholas R. J. Gascoigne
- the Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California 92037
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57
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Abstract
T cell receptor signaling allows the developing thymocyte to undergo positive or negative selection, which is required for the formation of a useful mature T cell repertoire. Recent developments include the finding that much of the Lck kinase (required to initiate T cell signaling) is already in an active configuration before signaling. The analog strength of antigen binding to the T cell receptor binding may be translated into a digital signal by the amount of time the TCR is paired with a co-receptor carrying Lck. Downstream, the cellular localization of MAP kinase signaling is determined by the strength of the signal and in turn predicts positive or negative selection. A novel protein, Themis, is important in crossing the positive selection developmental checkpoint, but its mode of action is still uncertain. Commitment to the CD4 or CD8 lineage is influenced by the amount of ZAP-70 signaling and also by closely regulated responsiveness to intrathymic cytokines such as IL7.
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Affiliation(s)
- Nicholas R J Gascoigne
- Department of Immunology and Microbial Science, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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Fu G, Gascoigne NRJ. Multiplexed labeling of samples with cell tracking dyes facilitates rapid and accurate internally controlled calcium flux measurement by flow cytometry. J Immunol Methods 2009; 350:194-9. [PMID: 19647745 DOI: 10.1016/j.jim.2009.07.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2009] [Revised: 07/21/2009] [Accepted: 07/21/2009] [Indexed: 11/28/2022]
Abstract
Calcium flux measurement is a crucial assay in lymphocyte activation. However, with the currently well established flow cytometric methods, it is a tedious procedure that is difficult to control to avoid variation between samples. This leads to unwanted sources of error that can make it problematic to interpret the results. Here we present an improved method that allows different cell populations to be tested in the same sample. Samples are pre-labeled with CFSE or Cy5 then mixed and stimulated to induce calcium flux. This facilitates more rapid and accurate measurement of calcium flux and also dramatically reduces the cost and effort required for this type of assay.
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Affiliation(s)
- Guo Fu
- Department of Immunology and Microbial Science, IMM1, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
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60
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Singleton KL, Roybal KT, Sun Y, Fu G, Gascoigne NRJ, van Oers NSC, Wülfing C. Spatiotemporal patterning during T cell activation is highly diverse. Sci Signal 2009; 2:ra15. [PMID: 19351954 DOI: 10.1126/scisignal.2000199] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Temporal and spatial variations in the concentrations of signaling intermediates in a living cell are important for signaling in complex networks because they modulate the probabilities that signaling intermediates will interact with each other. We have studied 30 signaling sensors, ranging from receptors to transcription factors, in the physiological activation of murine ex vivo T cells by antigen-presenting cells. Spatiotemporal patterning of these molecules was highly diverse and varied with specific T cell receptors and T cell activation conditions. The diversity and variability observed suggest that spatiotemporal patterning controls signaling interactions during T cell activation in a physiologically important and discriminating manner. In support of this, the effective clustering of a group of ligand-engaged receptors and signaling intermediates in a joint pattern consistently correlated with efficient T cell activation at the level of the whole cell.
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Affiliation(s)
- Kentner L Singleton
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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61
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62
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Mallaun M, Naeher D, Daniels MA, Yachi PP, Hausmann B, Luescher IF, Gascoigne NRJ, Palmer E. The T cell receptor's alpha-chain connecting peptide motif promotes close approximation of the CD8 coreceptor allowing efficient signal initiation. J Immunol 2008; 180:8211-21. [PMID: 18523287 DOI: 10.4049/jimmunol.180.12.8211] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The CD8 coreceptor contributes to the recognition of peptide-MHC (pMHC) ligands by stabilizing the TCR-pMHC interaction and enabling efficient signaling initiation. It is unclear though, which structural elements of the TCR ensure a productive association of the coreceptor. The alpha-chain connecting peptide motif (alpha-CPM) is a highly conserved sequence of eight amino acids in the membrane proximal region of the TCR alpha-chain. TCRs lacking the alpha-CPM respond poorly to low-affinity pMHC ligands and are unable to induce positive thymic selection. In this study we show that CD8 participation in ligand binding is compromised in T lineage cells expressing mutant alpha-CPM TCRs, leading to a slight reduction in apparent affinity; however, this by itself does not explain the thymic selection defect. By fluorescence resonance energy transfer microscopy, we found that TCR-CD8 association was compromised for TCRs lacking the alpha-CPM. Although high-affinity (negative-selecting) pMHC ligands showed reduced TCR-CD8 interaction, low-affinity (positive-selecting) ligands completely failed to induce molecular approximation of the TCR and its coreceptor. Therefore, the alpha-CPM of a TCR is an important element in mediating CD8 approximation and signal initiation.
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Affiliation(s)
- Michel Mallaun
- Laboratory of Transplantation Immunology and Nephrology, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
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63
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Rybakin V, Gascoigne NRJ. Molecular mechanism of allelic exclusion of TCR alpha chains. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.661.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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64
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Haraldsson MK, Louis-Dit-Sully CA, Lawson BR, Sternik G, Santiago-Raber ML, Gascoigne NRJ, Theofilopoulos AN, Kono DH. The lupus-related Lmb3 locus contains a disease-suppressing Coronin-1A gene mutation. Immunity 2008; 28:40-51. [PMID: 18199416 PMCID: PMC2274909 DOI: 10.1016/j.immuni.2007.11.023] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 11/12/2007] [Accepted: 11/28/2007] [Indexed: 10/22/2022]
Abstract
Here, we show that a lupus-suppressing locus is caused by a nonsense mutation of the filamentous actin-inhibiting Coronin-1A gene. This mutation was associated with developmental and functional alterations in T cells including reduced migration, survival, activation, and Ca2+ flux. T-dependent humoral responses were impaired, but no intrinsic B cell defects were detected. By transfer of T cells, it was shown that suppression of autoimmunity could be accounted for by the presence of the Coro1a(Lmb3) mutation in T cells. Our results demonstrate that Coronin-1A is required for the development of systemic lupus and identify actin-cytoskeleton regulatory proteins as potential targets for modulating autoimmune diseases.
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Affiliation(s)
| | | | - Brian R. Lawson
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037
| | - Gabriel Sternik
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037
| | | | | | | | - Dwight H. Kono
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037
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65
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Yachi PP, Lotz C, Ampudia J, Gascoigne NRJ. T cell activation enhancement by endogenous pMHC acts for both weak and strong agonists but varies with differentiation state. ACTA ACUST UNITED AC 2007; 204:2747-57. [PMID: 17954567 PMCID: PMC2118480 DOI: 10.1084/jem.20062610] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
T cells are extremely sensitive in their ability to find minute amounts of antigenic peptide in the midst of many endogenous peptides presented on an antigen-presenting cell. The role of endogenous peptides in the recognition of foreign peptide and hence in T cell activation has remained controversial for CD8(+) T cell activation. We showed previously that in a CD8(+) T cell hybridoma, nonstimulatory endogenous peptides enhance T cell sensitivity to antigen by increasing the coreceptor function of CD8. However, others were not able to detect such enhancement in naive and activated CD8(+) T cells. Here, we show that endogenous peptides substantially enhance the ability of T cells to detect antigen, an effect measurable by up-regulation of activation or maturation markers and by increased effector function. This enhancement is most pronounced in thymocytes, moderate in naive T cells, and mild in effector T cells. The importance of endogenous peptides is inversely proportional to the agonist activity of the stimulatory peptide presented. Unlike for CD4(+) T cells, the T cell receptor of CD8(+) T cells does not distinguish between endogenous peptides for their ability to enhance antigen recognition.
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Affiliation(s)
- Pia P Yachi
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037, USA
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66
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Daniels MA, Teixeiro E, Gill J, Hausmann B, Roubaty D, Holmberg K, Werlen G, Holländer GA, Gascoigne NRJ, Palmer E. Thymic selection threshold defined by compartmentalization of Ras/MAPK signalling. Nature 2006; 444:724-9. [PMID: 17086201 DOI: 10.1038/nature05269] [Citation(s) in RCA: 457] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2006] [Accepted: 09/18/2006] [Indexed: 01/02/2023]
Abstract
A healthy individual can mount an immune response to exogenous pathogens while avoiding an autoimmune attack on normal tissues. The ability to distinguish between self and non-self is called 'immunological tolerance' and, for T lymphocytes, involves the generation of a diverse pool of functional T cells through positive selection and the removal of overtly self-reactive thymocytes by negative selection during T-cell ontogeny. To elucidate how thymocytes arrive at these cell fate decisions, here we have identified ligands that define an extremely narrow gap spanning the threshold that distinguishes positive from negative selection. We show that, at the selection threshold, a small increase in ligand affinity for the T-cell antigen receptor leads to a marked change in the activation and subcellular localization of Ras and mitogen-activated protein kinase (MAPK) signalling intermediates and the induction of negative selection. The ability to compartmentalize signalling molecules differentially in the cell endows the thymocyte with the ability to convert a small change in analogue input (affinity) into a digital output (positive versus negative selection) and provides the basis for establishing central tolerance.
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Affiliation(s)
- Mark A Daniels
- Laboratory of Transplantation Immunology and Nephrology, Department of Research, University Hospital-Basel, Hebelstrasse 20, 4031 Basel, Switzerland
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67
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Abstract
We report a distinct microenvironment within the nuclear envelope (NE) in living cells revealed by a spectral shift of the fluorescent dye FM4-64 (N-(3-triethylammoniumpropyl)-4-(p-diethylaminophenylhexatrienyl)-pyridinium 2Br). The dye readily translocated to the NE at physiological temperature where it exhibited enhanced fluorescence when excited at 620-650 nm in contrast to 480-520 nm excitation in the endocytic pathway and in the endoplasmic reticulum (ER). In vitro data indicated that the dye reveals an enrichment of negatively charged lipids, presumably due to local phospholipid synthesis. Dual-excitation imaging of FM4-64 in relation to lamina-associated polypeptide-1-green fluorescent protein during mitosis suggested that the disassembly of NE preserves microscale lipid complexes in the ER. Convolutions of NE in cancer or primary cells were readily visualized, and killing of tumor cells by T cells was marked by sudden loss of the long-wavelength excited fluorescence in the NE coincident with apoptosis. This report of FM4-64 as the first vital dye sensitive to the NE environment opens new ways for real-time visualization and functional studies of the NE.
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Affiliation(s)
- Tomasz Zal
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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68
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Yachi PP, Ampudia J, Zal T, Gascoigne NRJ. Altered Peptide Ligands Induce Delayed CD8-T Cell Receptor Interaction—a Role for CD8 in Distinguishing Antigen Quality. Immunity 2006; 25:203-11. [PMID: 16872849 DOI: 10.1016/j.immuni.2006.05.015] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2006] [Revised: 04/21/2006] [Accepted: 05/11/2006] [Indexed: 10/24/2022]
Abstract
How T cells translate T cell receptor (TCR) recognition of almost identical pMHC ligands into distinct biological responses has remained enigmatic. Although differences in affinity or off rate are important, they offer at best an incomplete explanation. By using Förster resonance energy transfer (FRET), we have visualized the ligand-induced interaction between OT-I TCR and CD8. We found that both recruitment of TCR to the immunological synapse and the TCR-CD8 interaction induced by weak agonists (positive-selecting ligands) was delayed but not necessarily weaker than strong agonists (negative selectors). A delayed and perhaps longer lasting CD8-TCR interaction results in delayed phospho-ERK recruitment to the synapse. The kinetics of the TCR-CD8 interaction can reconcile previously anomalous data, where biological activity did not correlate with TCR-pMHC binding kinetics for certain ligands. Our findings indicate that the T cell translates antigen recognition into T cell responses by differential recruitment of CD8 to the TCR.
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Affiliation(s)
- Pia P Yachi
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
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69
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Bosco N, Hung HC, Pasqual N, Jouvin-Marche E, Marche PN, Gascoigne NRJ, Ceredig R. Role of the T cell receptor alpha chain in the development and phenotype of naturally arising CD4+CD25+ T cells. Mol Immunol 2006; 43:246-54. [PMID: 16199261 DOI: 10.1016/j.molimm.2005.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2004] [Accepted: 02/04/2005] [Indexed: 11/17/2022]
Abstract
The T cell receptor alpha chain repertoire and the possible influence of the alpha chain on the development and phenotype of naturally arising mouse CD4+CD25+ T cells have not been extensively analysed. We used all available Valpha-specific monoclonal antibodies and a sensitive multiplex genomic DNA PCR assay to study the Valpha repertoire of CD4+CD25+ T cells in normal mice. To address whether CD4+CD25+ T cells express two TCR alpha chains, we have carried out four-colour flow cytometry using combinations of the available anti-Valpha reagents in mice where one allele of the TCRA locus had been inactivated. Results indicate that the Valpha repertoire of CD4+CD25+ T cells is as diverse as their CD25- partners. In addition, CD4+CD25+ T cells develop normally in Tcralpha+/- mice and we show for the first time that despite expressing only one TCRalpha chain, they retain their characteristic CD4(low), CD3(low), TCRbeta(low), CD5(high), CD45RB(low) and cytoplasmic CD152(high) phenotype.
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Affiliation(s)
- Nabil Bosco
- Unité 548 INSERM, DRDC, CEA-G, 17 rue des Martyrs, F-38054 Grenoble, France.
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70
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Lin MY, Zal T, Ch'en IL, Gascoigne NRJ, Hedrick SM. A pivotal role for the multifunctional calcium/calmodulin-dependent protein kinase II in T cells: from activation to unresponsiveness. J Immunol 2005; 174:5583-92. [PMID: 15843557 DOI: 10.4049/jimmunol.174.9.5583] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Stimulation of the TCR leads to an oscillatory release of free calcium that activates members of the calcium/calmodulin-dependent protein kinase II (CaMKII) family. The CaMKII molecules have profound and lasting effects on cellular signaling in several cell types, yet the role of CaMKII in T cells is still poorly characterized. In this report we describe a splice variant of CaMKIIbeta, CaMKIIbeta'e, in mouse T cells. We have determined its function, along with that of CaMKIIgamma, by introducing the active and kinase-dead mutants into activated P14 TCR transgenic T cells using retroviral transduction. Active CaMKII enhanced the proliferation and cytotoxic activity of T cells while reducing their IL-2 production. Furthermore, it induced a profound state of unresponsiveness that could be overcome only by prolonged culture in IL-2. These results indicate that members of the CaMKII family play an important role in regulation of CD8 T cell proliferation, cytotoxic effector function, and the response to restimulation.
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Affiliation(s)
- Meei Yun Lin
- Division of Biological Sciences, The Cancer Center, and Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
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71
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Abstract
Fluorescent resonance energy transfer (FRET) imaging techniques can be used to visualize protein-protein interactions in real-time with subcellular resolution. Imaging of sensitized fluorescence of the acceptor, elicited during excitation of the donor, is becoming the most popular method for live FRET (3-cube imaging) because it is fast, nondestructive, and applicable to existing widefield or confocal microscopes. Most sensitized emission-based FRET indices respond nonlinearly to changes in the degree of molecular interaction and depend on the optical parameters of the imaging system. This makes it difficult to evaluate and compare FRET imaging data between laboratories. Furthermore, photobleaching poses a problem for FRET imaging in timelapse experiments and three-dimensional reconstructions. We present a 3-cube FRET imaging method, E-FRET, which overcomes both of these obstacles. E-FRET bridges the gap between the donor recovery after acceptor photobleaching technique (which allows absolute measurements of FRET efficiency, E, but is not suitable for living cells), and the sensitized-emission FRET indices (which reflect FRET in living cells but lack the quantitation and clarity of E). With E-FRET, we visualize FRET in terms of true FRET efficiency images (E), which correlate linearly with the degree of donor interaction. We have defined procedures to incorporate photobleaching correction into E-FRET imaging. We demonstrate the benefits of E-FRET with photobleaching correction for timelapse and three-dimensional imaging of protein-protein interactions in the immunological synapse in living T-cells.
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Affiliation(s)
- Tomasz Zal
- Department of Immunology, The Scripps Research Institute, La Jolla, California 92037, USA.
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72
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Niederberger N, Buehler LK, Ampudia J, Gascoigne NRJ. Thymocyte stimulation by anti-TCR-beta, but not by anti-TCR-alpha, leads to induction of developmental transcription program. J Leukoc Biol 2005; 77:830-841. [PMID: 15661827 DOI: 10.1189/jlb.1004608] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2004] [Revised: 12/15/2004] [Accepted: 12/29/2004] [Indexed: 12/19/2022] Open
Abstract
Anti-T cell receptor (aTCR) antibody (Ab) stimulation of T cells results in TCR down-modulation and T cell activation. Differences in the effect of anti-alpha-chain and beta-chain Ab have been reported on thymocytes. Anti-beta-chain Ab but not anti-alpha-chain reagents cause long-term TCR down-modulation. However, both types of Ab result in TCR cross-linking and activate early steps in signal transduction. In this study, we show that TCR internalization and calcium flux, hallmarks of T cell activation, are similar with aValpha and aVbeta treatment. Therefore, we have compared the gene expression profiles of preselection thymocytes stimulated with these reagents. We find that aValpha treatment does not cause any significant change in gene expression compared with control culture conditions. In contrast, aVbeta stimulation results in numerous changes in gene expression. The alterations of expression of genes known to be expressed in thymocytes are similar to changes caused by positive thymic selection, suggesting that the expression of some of the genes without known roles in thymocyte development and of novel genes whose expression is found to be altered may also be involved in this process.
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Affiliation(s)
- Nathalie Niederberger
- Department of Immunology, IMM1, The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla, CA 92037, USA
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73
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Gronski MA, Boulter JM, Moskophidis D, Nguyen LT, Holmberg K, Elford AR, Deenick EK, Kim HO, Penninger JM, Odermatt B, Gallimore A, Gascoigne NRJ, Ohashi PS. TCR affinity and negative regulation limit autoimmunity. Nat Med 2004; 10:1234-9. [PMID: 15467726 DOI: 10.1038/nm1114] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2004] [Accepted: 09/13/2004] [Indexed: 11/09/2022]
Abstract
Autoimmune diseases are often mediated by self-reactive T cells, which must be activated to cause immunopathology. One mechanism, known as molecular mimicry, proposes that self-reactive T cells may be activated by pathogens expressing crossreactive ligands. Here we have developed a model to investigate how the affinity of the T-cell receptor (TCR) for the activating agent influences autoimmunity. Our model shows that an approximately fivefold difference in the TCR affinity for the activating ligand results in a 50% reduction in the incidence of autoimmunity. A reduction in TCR-ligand affinity to approximately 20 times lower than normal does not induce autoimmunity despite the unexpected induction of cytotoxic T lymphocytes (CTLs) and insulitis. Furthermore, in the absence of a key negative regulatory molecule, Cbl-b, 100% of mice develop autoimmunity upon infection with viruses encoding the lower-affinity ligand. Therefore, autoimmune disease is sensitive both to the affinity of the activating ligand and to normal mechanisms that negatively regulate the immune response.
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Affiliation(s)
- Matthew A Gronski
- Institute for Breast Cancer Research, Ontario Cancer Institute, Departments of Medical Biophysics and Immunology, University of Toronto, Toronto, Ontario M5G 2C1, Canada
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74
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Zal T, Gascoigne NRJ. Using live FRET imaging to reveal early protein-protein interactions during T cell activation. Curr Opin Immunol 2004; 16:674-83. [PMID: 15818893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The emerging challenge for proteomics in general and lymphocyte biology in particular is to understand protein-protein interactions in the dynamic context of the living cell. Particularly interesting are the molecular dynamics of the T cell receptor-CD3 complex and other immunoreceptors in immune synapses. Fluorescence (or Förster) resonance energy transfer (FRET) is one of the few techniques that are capable of giving dynamic information about the nanometer-range proximity between molecules, as opposed to simply the subcellular co-localization that is provided by fluorescence microscopy. Spectral changes in fluorescence intensity and down modulation of donor lifetime are the basis for rapidly developing approaches to real-time FRET imaging. With two-photon excitation, FRET can now be extended to in vivo imaging.
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Affiliation(s)
- Tomasz Zal
- Department of Immunology, The Scripps Research Institute, La Jolla, California 92037, USA.
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75
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Abstract
T cell receptor engagement promotes proliferation, differentiation, survival, or death of T lymphocytes. The affinity/avidity of the TCR ligand and the maturational stage of the T cell are thought to be principal determinants of the outcome of TCR engagement. We demonstrate in this study that the same mouse TCR preferentially uses distinct residues of homologous peptides presented by the MHC molecules to promote specific cellular responses. The preference for distinct TCR contacts depends on neither the affinity/avidity of TCR engagement (except in the most extreme ranges), nor the maturity of engaged T cells. Thus, different portions of the TCR ligand appear capable of biasing T cells toward specific biological responses. These findings explain differences in functional versatility of TCR ligands, as well as anomalies in the relationship between affinity/avidity of the TCR for the peptide/MHC and cellular responses of T cells.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antigen Presentation
- Epitope Mapping
- Epitopes, T-Lymphocyte/chemistry
- Epitopes, T-Lymphocyte/physiology
- Ligands
- Mice
- Mice, Transgenic
- Models, Molecular
- Peptides/chemical synthesis
- Peptides/immunology
- Protein Binding
- Protein Footprinting
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/metabolism
- Receptors, Antigen, T-Cell/physiology
- Structure-Activity Relationship
- T-Lymphocyte Subsets
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Affiliation(s)
- Fabio R Santori
- Michael Heidelberger Division of Immunology, Department of Pathology and New York University Cancer Center, New York University School of Medicine, New York, NY 10016, USA
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76
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Abstract
The development of new imaging techniques has made it possible to investigate the dynamic movements of molecules involved in T-cell signalling. Fluorescence resonance energy transfer (FRET) imaging allows the investigation of protein-protein interactions in live cells, and has demonstrated that T-cell receptors (TCRs) and CD4 are brought together in the immunological synapse during antigen recognition. This interaction is inhibited by antagonist ligands. Antagonism works through competition between agonist and antagonist ligands for TCR binding, as well as through feedback via the SHP-1 tyrosine phosphatase and extracellular signal-related kinase. Early signalling events result in the clustering of co-receptors and TCRs at the synapse, and the activation of various signalling molecules. Recent data show that some T-cell signalling precedes the formation of the mature form of the immunological synapse, but that full T-cell activation depends on sustained signalling, which in turn requires the synapse.
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Affiliation(s)
- Nicholas R J Gascoigne
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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77
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Abstract
The emerging challenge for proteomics in general and lymphocyte biology in particular is to understand protein-protein interactions in the dynamic context of the living cell. Particularly interesting are the molecular dynamics of the T cell receptor-CD3 complex and other immunoreceptors in immune synapses. Fluorescence (or Förster) resonance energy transfer (FRET) is one of the few techniques that are capable of giving dynamic information about the nanometer-range proximity between molecules, as opposed to simply the subcellular co-localization that is provided by fluorescence microscopy. Spectral changes in fluorescence intensity and down modulation of donor lifetime are the basis for rapidly developing approaches to real-time FRET imaging. With two-photon excitation, FRET can now be extended to in vivo imaging.
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Affiliation(s)
- Tomasz Zal
- Department of Immunology, The Scripps Research Institute, La Jolla, California 92037, USA.
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78
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Alam SM, Gascoigne NRJ. Binding kinetics of superantigen with TCR and MHC class II. Methods Mol Biol 2004; 214:65-85. [PMID: 12489455 DOI: 10.1385/1-59259-367-4:065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Affiliation(s)
- S Munir Alam
- Division of Rheumatology, Allergy and Clinical Immunology, Department of Medicine, Duke University Medical Center, Durham, NC, USA
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79
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Holmberg K, Mariathasan S, Ohteki T, Ohashi PS, Gascoigne NRJ. TCR binding kinetics measured with MHC class I tetramers reveal a positive selecting peptide with relatively high affinity for TCR. J Immunol 2003; 171:2427-34. [PMID: 12928390 DOI: 10.4049/jimmunol.171.5.2427] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The interaction between TCR and peptide-MHC (pMHC) complexes is crucial for the activation of T cells as well as for positive and negative selection in the thymus. The kinetics and affinity of this interaction and the densities of TCR and pMHC complexes on the cell surface are determining factors for different outcomes during thymic selection. In general, it is thought that agonist pMHC, which cause negative selection, have higher affinities and, in particular, slower off-rates than partial or weak agonists and antagonists, which cause positive selection. In this study, we have used pMHC tetramers to investigate the kinetics of TCR-pMHC interaction for agonist, weak agonist, and antagonist ligands of the anti-lymphocytic choriomeningitis virus P14 TCR. Kinetics determined on the cell surface may be biologically more relevant than methods using soluble proteins. We can distinguish between agonists and weak agonists or antagonists based on the half-life and the avidity of tetramer-TCR interaction. Furthermore, we show that a weak agonist self-peptide that positively selects P14 TCR(+) thymocytes has a tetramer half-life and avidity only slightly weaker than strong agonists. We show that, in fact, it can act as quite a strong agonist, but that its poor ability to stabilize MHC causes it instead to have a weak agonist phenotype.
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MESH Headings
- Amino Acid Substitution/immunology
- Animals
- Antigen Presentation/immunology
- Binding, Competitive/immunology
- Cell Line, Tumor
- Cell Membrane/immunology
- Cell Membrane/metabolism
- Dose-Response Relationship, Immunologic
- Down-Regulation/immunology
- Epitopes, T-Lymphocyte/metabolism
- H-2 Antigens/metabolism
- Half-Life
- Histocompatibility Antigen H-2D
- Kinetics
- Lymphocyte Activation
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Oligopeptides/agonists
- Oligopeptides/antagonists & inhibitors
- Oligopeptides/metabolism
- Protein Binding/immunology
- Receptors, Antigen, T-Cell/agonists
- Receptors, Antigen, T-Cell/antagonists & inhibitors
- Receptors, Antigen, T-Cell/biosynthesis
- Receptors, Antigen, T-Cell/metabolism
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
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Affiliation(s)
- Kaisa Holmberg
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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80
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Niederberger N, Holmberg K, Alam SM, Sakati W, Naramura M, Gu H, Gascoigne NRJ. Allelic exclusion of the TCR alpha-chain is an active process requiring TCR-mediated signaling and c-Cbl. J Immunol 2003; 170:4557-63. [PMID: 12707333 DOI: 10.4049/jimmunol.170.9.4557] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Phenotypic allelic exclusion at the TCRalpha locus is developmentally regulated in thymocytes. Many immature thymocytes express two cell surface alpha-chain species. Following positive selection, the vast majority of mature thymocytes and peripheral T cells display a single cell surface alpha-chain. A posttranslational mechanism occurring at the same time as positive selection and TCR up-regulation leads to this phenotypic allelic exclusion. Different models have been proposed to explain the posttranslational regulation of the alpha-chain allelic exclusion. In this study, we report that allelic exclusion is not regulated by competition between distinct alpha-chains for a single beta-chain, as proposed by the dueling alpha-chain model, nor by limiting CD3 zeta-chain in mature TCR(high) thymocytes. Our data instead favor the selective retention model where the positive selection signal through the TCR leads to phenotypic allelic exclusion by specifically maintaining cell surface expression of the selected alpha-chain while the nonselected alpha-chain is internalized. The use of inhibitors specific for Lck and/or other Src kinases indicates a role for these protein tyrosine kinases in the signaling events leading to the down-regulation of the nonselectable alpha-chain. Loss of the ubiquitin ligase/TCR signaling adapter molecule c-Cbl, which is important in TCR down-modulation and is a negative regulator of T cell signaling, leads to increased dual alpha-chain expression on the cell surface of double-positive thymocytes. Thus, not only is there an important role for TCR signaling in causing alpha-chain allelic exclusion, but differential ubiquitination by c-Cbl may be an important factor in causing only the nonselected alpha-chain to be down-modulated.
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MESH Headings
- Alleles
- Animals
- Antibody Affinity/genetics
- Binding, Competitive/genetics
- Binding, Competitive/immunology
- Cross-Linking Reagents/metabolism
- Dimethyl Sulfoxide/pharmacology
- Down-Regulation/drug effects
- Down-Regulation/genetics
- Down-Regulation/immunology
- Fetus
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/immunology
- Genes, T-Cell Receptor alpha
- Genes, T-Cell Receptor beta
- Immune Sera/metabolism
- Immunophenotyping
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/antagonists & inhibitors
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/biosynthesis
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/physiology
- Membrane Proteins/biosynthesis
- Membrane Proteins/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Mutant Strains
- Mice, Transgenic
- Organ Culture Techniques
- Proto-Oncogene Proteins/deficiency
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/physiology
- Proto-Oncogene Proteins c-cbl
- Pyrazoles/pharmacology
- Pyrimidines/pharmacology
- Receptors, Antigen, T-Cell/biosynthesis
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell, alpha-beta/antagonists & inhibitors
- Receptors, Antigen, T-Cell, alpha-beta/biosynthesis
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Signal Transduction/drug effects
- Signal Transduction/genetics
- Signal Transduction/immunology
- Thymus Gland/cytology
- Thymus Gland/immunology
- Thymus Gland/metabolism
- Ubiquitin-Protein Ligases
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81
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Sim BC, Holmberg K, Sidobre S, Naidenko O, Niederberger N, Marine SD, Kronenberg M, Gascoigne NRJ. Surprisingly minor influence of TRAV11 (Valpha14) polymorphism on NK T-receptor mCD1/alpha-galactosylceramide binding kinetics. Immunogenetics 2003; 54:874-83. [PMID: 12671739 DOI: 10.1007/s00251-002-0532-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2002] [Revised: 11/20/2002] [Indexed: 10/25/2022]
Abstract
Defects in natural killer T (NK T) cell function and of interleukin-4 -production in SJL and NOD mice have been linked to susceptibility to autoimmune disease. As SJL and NOD mice both carry the T-cell receptor (TCR) alpha-chain locus "c" (Tcra(c)) haplotype, found in few other strains, we have attempted to determine the influence of Tcra polymorphism on NK T-cell recognition of ligand, selection, and immune responses. The majority of NK T cells use an "invariant" TRAV11J15 (previously called AV14J18 or Valpha14 Jalpha281) alpha- chain paired with either TRBV13-2, BV29, or BV1 to recognize ligands presented by mCD1 molecules, including the glycolipid alpha-galactosylceramide (alpha-GalCer). Sequencing of TRAV11 from the mouse strains B10.A (encoding the Tcra(b) haplotype), B10.A- Tcra(c), and NOD (Tcra(c)) shows that Tcra(c) has a single TRAV11 gene (TRAV11*01) and that Tcra(b) has a single expressed gene (TRAV11*02), plus a closely related pseudogene. There is no apparent difference in alpha-chain J-region usage or in the CDR3alpha sequence at the TRAV11-J15 junction between the haplotypes in TRAV11-bearing NK T cells. Using Biacore and tetramer-binding and decay assays, we have determined that the interaction between Tcra(c) TRAV11*01 NK T TCR and the mCD1/alpha-GalCer complex is slightly weaker than that of Tcra(b) (i.e., TRAV11*02) NK T TCR. These differences are minor compared with differences between agonist and antagonist ligands in other TCR systems, suggesting that it is unlikely that TCR polymorphism explains the defect in NK T cells in the autoimmune mouse strains.
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MESH Headings
- Amino Acid Sequence
- Animals
- Animals, Congenic
- Antigens, CD1/chemistry
- Antigens, CD1/metabolism
- Base Sequence
- DNA/genetics
- Galactosylceramides/metabolism
- Genes, T-Cell Receptor alpha
- Haplotypes
- Killer Cells, Natural/immunology
- Killer Cells, Natural/metabolism
- Kinetics
- Mice
- Mice, Inbred C57BL
- Mice, Inbred NOD
- Molecular Sequence Data
- Polymorphism, Genetic
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
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Affiliation(s)
- Bee-Cheng Sim
- IMM1, Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037, USA
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82
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Sidobre S, Naidenko OV, Sim BC, Gascoigne NRJ, Garcia KC, Kronenberg M. The V alpha 14 NKT cell TCR exhibits high-affinity binding to a glycolipid/CD1d complex. J Immunol 2002; 169:1340-8. [PMID: 12133957 DOI: 10.4049/jimmunol.169.3.1340] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Most CD1d-dependent NKT cells in mice have a canonical V alpha 14J alpha 18 TCR rearrangement. However, relatively little is known concerning the molecular basis for their reactivity to glycolipid Ags presented by CD1d. Using glycolipid Ags, soluble forms of a V alpha 14 NKT cell-derived TCR, and mutant and wild-type CD1d molecules, we probed the TCR/CD1d interaction by surface plasmon resonance, tetramer equilibrium staining, and tetramer staining decay experiments. By these methods, several CD1d alpha-helical amino acids could be defined that do not greatly alter lipid binding, but that affect the interaction with the TCR. Binding of the V alpha 14(+) TCR to CD1d requires the agonist alpha-galactosylceramide (alpha-GalCer), as opposed to the nonantigenic beta-galactosylceramide, although both Ags bind to CD1d, indicating that the carbohydrate moiety of the CD1d-bound Ag plays a major role in the TCR interaction. The TCR has a relatively high-affinity binding to the alpha-GalCer/CD1d complex, with a particularly slow off rate. These unique properties are consistent with the coreceptor-independent action of the V alpha 14 TCR and may be related to the intense response to alpha-GalCer by NKT cells in vivo.
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Affiliation(s)
- Stéphane Sidobre
- Division of Developmental Immunology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121, USA
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83
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Huang J, Lo PF, Zal T, Gascoigne NRJ, Smith BA, Levin SD, Grey HM. CD28 plays a critical role in the segregation of PKC theta within the immunologic synapse. Proc Natl Acad Sci U S A 2002; 99:9369-73. [PMID: 12077322 PMCID: PMC123147 DOI: 10.1073/pnas.142298399] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The signaling pathways that lead to the localization of cellular protein to the area of interaction between T cell and antigen-presenting cell and the mechanism by which these molecules are further sorted to the peripheral supramolecular activation cluster or central supramolecular activation cluster regions of the immunologic synapse are poorly understood. In this study, we investigated the functional involvement of CD28 costimulation in the T cell receptor (TCR)-mediated immunologic synapse formation with respect to protein kinase C (PKC)theta; localization. We showed that CD3 crosslinking alone was sufficient to induce PKC theta; capping in naive CD4(+) T cells. Studies with pharmacologic inhibitors and knockout mice showed that the TCR-derived signaling that drives PKC theta; membrane translocation requires the Src family kinase, Lck, but not Fyn. In addition, a time course study of the persistence of T cell molecules to the immunologic synapse indicated that PKC theta;, unlike TCR, persisted in the synapse for at least 4 h, a time that is sufficient for commitment of a T cell to cell division. Finally, by using TCR-transgenic T cells from either wild-type or CD28-deficient mice, we showed that CD28 expression was required for the formation of the mature immunologic synapse, because antigen stimulation of CD28(-) T cells led to a diffuse pattern of localization of PKC theta; and lymphocyte function-associated antigen-1 in the immunologic synapse, in contrast to the central supramolecular activation cluster localization of PKC theta; in CD28(+) T cells.
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Affiliation(s)
- Jianyong Huang
- Division of Immunochemistry, La Jolla Institute for Allergy and Immunology, 10355 Science Center Drive, San Diego, CA 92121, USA
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84
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Zal T, Zal MA, Gascoigne NRJ. Inhibition of T cell receptor-coreceptor interactions by antagonist ligands visualized by live FRET imaging of the T-hybridoma immunological synapse. Immunity 2002; 16:521-34. [PMID: 11970876 DOI: 10.1016/s1074-7613(02)00301-1] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The diverse effects of TCR agonists and antagonists on T cell activation are believed to be modified by the differential recruitment of CD4 or CD8 coreceptors to the TCR-MHCp complex. We used three-dimensional live cell imaging of fluorescence resonance energy transfer (FRET) between CD3zeta and CD4 fused to variants of the green fluorescent protein to investigate TCR-CD4 interactions during T cell activation. We demonstrate that recognition of agonist MHCp complexes triggers intermolecular interaction between CD4 and TCR, detectable across the T-hybridoma-APC contact area. This interaction is blocked by the presence of antagonist ligands without decreasing the recruitment of zeta and CD4 or preventing their partial colocalization in the immunological synapse.
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Affiliation(s)
- Tomasz Zal
- Deptartment of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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85
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Abstract
The addition of sialic acid to O-linked glycans of the T-cell co-receptor CD8 is regulated during thymocyte differentiation. Two recent papers have shown that this glycosylation changes the avidity of the interaction between CD8 and MHC class I proteins, potentially altering signalling thresholds in thymocyte differentiation.
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Affiliation(s)
- Nicholas R J Gascoigne
- Department of Immunology, IMM1, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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86
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Redpath S, Alam SM, Lin CM, O’Rourke AM, Gascoigne NRJ. Cutting Edge: Trimolecular Interaction of TCR with MHC Class II and Bacterial Superantigen Shows a Similar Affinity to MHC:Peptide Ligands. The Journal of Immunology 1999. [DOI: 10.4049/jimmunol.163.1.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Bacterial superantigens such as Staphylococcus aureus enterotoxin A (SEA) are very potent stimulators of T cells. They bind to the Vβ region of the TCR and to MHC class II, stimulating T cells at nanomolar concentrations. Using surface plasmon resonance measurements, we find that binding between the individual components of the complex (TCR-class II, TCR-SEA, SEA-class II) is very weak, but that the stability of the trimolecular complex is considerably enhanced, reaching an affinity similar to that found for TCR interactions with MHC:peptide ligand. Thus, the potency of SEA in stimulation of T cells is not due to particularly strong affinities between the proteins, but to a cooperative effect of interactions in the TCR-SEA-MHC class II trimolecular complex that brings the kinetics into a similar range to binding of conventional Ags. This range may be the optimum for T cell activation.
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Affiliation(s)
- Stella Redpath
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037
| | - S. Munir Alam
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037
| | - Christina M. Lin
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037
| | - Anne M. O’Rourke
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037
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87
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Redpath S, Angulo A, Gascoigne NRJ, Ghazal P. Murine Cytomegalovirus Infection Down-Regulates MHC Class II Expression on Macrophages by Induction of IL-10. The Journal of Immunology 1999. [DOI: 10.4049/jimmunol.162.11.6701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Herpesviruses utilize many strategies for weakening the host immune response. For CMV, this includes avoidance of NK clearance and inhibition of MHC class I and class II presentation pathways. In this study, we report that mouse CMV (MCMV) specifically causes a premature and transient activation of host IL-10 very early in the course of infection, resulting in a dramatic and selective reduction in MHC class II surface expression. The expression of IL-10 is normally late in the immune response to a pathogen, serving to dampen the response by suppression of the production of inflammatory cytokines. In infection of macrophages, we show that MCMV induces the production of IL-10, leading to an early and selective reduction in the expression of MHC class II on the surface of the cells. Inhibition of MHC class II expression was not observed in the presence of neutralizing Abs to IL-10 or in macrophages from IL-10-deficient mice. Moreover, MCMV-infected IL-10-deficient mice developed an early and significantly more robust macrophage MHC class II induction than normal mice. Altogether, our results demonstrate that viral induction of an IL-10 autocrine pathway plays an essential early role in selectively reducing MHC class II expression on the surface of APC prior to stimulation by IFN-γ.
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Affiliation(s)
| | | | | | - Peter Ghazal
- †Molecular Biology, Division of Virology, The Scripps Research Institute, La Jolla, CA 92037
- *Immunology and
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88
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Sim BC, Gascoigne NRJ. Reciprocal Expression in CD4 or CD8 Subsets of Different Members of the Vα11 Gene Family Correlates with Sequence Polymorphism. The Journal of Immunology 1999. [DOI: 10.4049/jimmunol.162.6.3153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Previous staining studies with TCR Vα11-specific mAbs showed that Vα11.1/11.2 (AV11S1 and S2) expression was selectively favored in the CD4+ peripheral T cell population. As this phenomenon was essentially independent of the MHC haplotype, it was suggested that AV11S1 and S2 TCRs exert a preference for recognition of class II MHC molecules. The Vα segment of the TCR α-chain is suggested to have a primary role in shaping the T cell repertoire due to selection for class I or II molecules acting through the complementarity determining regions (CDR) 1α and CDR2α residues. We have analyzed the repertoire of Vα11 family members expressed in C57BL/6 mice and have identified a new member of this family; AV11S8. We show that, whereas AV11S1 and S2 are more frequent in CD4+ cells, AV11S3 and S8 are more frequent in CD8+ cells. The sequences in the CDR1α and CDR2α correlate with differential expression in CD4+ or CD8+ cells, a phenomenon that is also observed in BALB/c mice. With no apparent restriction in TCR Jα usage or CDR3α length in C57BL/6, these findings support the idea of Vα-dependent T cell repertoire selection through preferential recognition of MHC class I or class II molecules.
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Affiliation(s)
- Bee-Cheng Sim
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037
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89
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Alam SM, Gascoigne NRJ. Posttranslational Regulation of TCR Vα Allelic Exclusion During T Cell Differentiation. The Journal of Immunology 1998. [DOI: 10.4049/jimmunol.160.8.3883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
We have previously shown that phenotypic allelic exclusion of TCR α-chain is functional only in mature thymocytes. A significant proportion of immature thymocytes (TCRlow) express more than one cell surface α-chain, but mature thymocytes (TCRhigh) show phenotypic allelic exclusion and express only a single α-chain. We have analyzed thymocytes for both surface and intracellular α-chain expression and find that the majority of mature thymocytes express a second α-chain intracellularly. This result is predicted by a model in which the developmentally regulated allelic exclusion of the TCR α-chain is caused by competition between α-chains for the β-chain rather than by models in which one α-chain is down-regulated or in which selection favors cells with only a single α-chain species. Changes in the relative amounts of α- and β-chains available for pairing may therefore allow competition between the two α-chains for the β-chain. Peripheral T cells also frequently express second α-chains in the cytoplasm (18–27%), despite a rather low frequency of dual α-chain expression on the cell surface (2–4%). The frequency of nonsurface expressed α-chains is reduced somewhat compared with thymocytes, indicating that an additional level of control of allelic exclusion operates during the maturation of peripheral T cells.
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Affiliation(s)
- S. Munir Alam
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037
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Sim BC, Wung JL, Gascoigne NRJ. Polymorphism Within a TCRAV Family Influences the Repertoire Through Class I/II Restriction. The Journal of Immunology 1998. [DOI: 10.4049/jimmunol.160.3.1204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Antibody-staining experiments have shown that closely related members of the TCRAV3 family are reciprocally selected into the CD4 or CD8 peripheral T cell subsets. This has been attributed to the individual AV3 members interacting preferentially with either MHC class I or MHC class II molecules. Single amino acid residues present in the complementarity-determining regions (CDR) CDR1α and CDR2α are important in determining MHC class specificity. We have now extended these observations to survey the expressed repertoire of the AV3 family in C57BL/6 mice. Three of the four expressed AV3 members are preferentially selected into the CD4+ subset of T cells. These share the same amino acid residue in both CDR1α and CDR2α that differ from the only CD8-skewed member. Preferential expression of an individual AV3 is not caused by other endogenous α- or β-chains, by any conserved CDR3 sequence, or by the usage of TCRAJ regions. This study shows that residues in the CDR1 and CDR2 regions are primary determinants for MHC class discrimination and suggests that polymorphism found within a TCRAV family has an important effect on the overall shaping of the T cell repertoire.
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Affiliation(s)
- Bee-Cheng Sim
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037
| | - Jay L. Wung
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037
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