scholarly journals MR1-restricted MAIT cells display ligand discrimination and pathogen selectivity through distinct T cell receptor usage

2014 ◽  
Vol 211 (8) ◽  
pp. 1601-1610 ◽  
Author(s):  
Marielle C. Gold ◽  
James E. McLaren ◽  
Joseph A. Reistetter ◽  
Sue Smyk-Pearson ◽  
Kristin Ladell ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Direct Consequence ◽  
Cell Receptor ◽  
Recognition System ◽  
Dependent Manner ◽  
Cell Repertoire ◽  
Mait Cells ◽  
Cell Clones ◽  
Mait Cell

Mucosal-associated invariant T (MAIT) cells express a semi-invariant T cell receptor (TCR) that detects microbial metabolites presented by the nonpolymorphic major histocompatibility complex (MHC)–like molecule MR1. The highly conserved nature of MR1 in conjunction with biased MAIT TCRα chain usage is widely thought to indicate limited ligand presentation and discrimination within a pattern-like recognition system. Here, we evaluated the TCR repertoire of MAIT cells responsive to three classes of microbes. Substantial diversity and heterogeneity were apparent across the functional MAIT cell repertoire as a whole, especially for TCRβ chain sequences. Moreover, different pathogen-specific responses were characterized by distinct TCR usage, both between and within individuals, suggesting that MAIT cell adaptation was a direct consequence of exposure to various exogenous MR1-restricted epitopes. In line with this interpretation, MAIT cell clones with distinct TCRs responded differentially to a riboflavin metabolite. These results suggest that MAIT cells can discriminate between pathogen-derived ligands in a clonotype-dependent manner, providing a basis for adaptive memory via recruitment of specific repertoires shaped by microbial exposure.

Canonical T cell receptor docking on peptide–MHC is essential for T cell signaling

Science ◽  
2021 ◽  
Vol 372 (6546) ◽  
pp. eabe9124
Author(s):  
Pirooz Zareie ◽  
Christopher Szeto ◽  
Carine Farenc ◽  
Sachith D. Gunasinghe ◽  
Elizabeth M. Kolawole ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Signaling ◽  
T Cell Receptor ◽  
T Cell Activation ◽  
Cell Activation ◽  
Direct Consequence ◽  
Cell Receptor ◽  
T Cell Signaling ◽  
Cell Repertoire

T cell receptor (TCR) recognition of peptide–major histocompatibility complexes (pMHCs) is characterized by a highly conserved docking polarity. Whether this polarity is driven by recognition or signaling constraints remains unclear. Using “reversed-docking” TCRβ-variable (TRBV) 17+ TCRs from the naïve mouse CD8+ T cell repertoire that recognizes the H-2Db–NP366 epitope, we demonstrate that their inability to support T cell activation and in vivo recruitment is a direct consequence of reversed docking polarity and not TCR–pMHCI binding or clustering characteristics. Canonical TCR–pMHCI docking optimally localizes CD8/Lck to the CD3 complex, which is prevented by reversed TCR–pMHCI polarity. The requirement for canonical docking was circumvented by dissociating Lck from CD8. Thus, the consensus TCR–pMHC docking topology is mandated by T cell signaling constraints.

scholarly journals Diversification of the antigen-specific T cell receptor repertoire after varicella zoster vaccination

2016 ◽  
Vol 8 (332) ◽  
pp. 332ra46-332ra46 ◽  
Author(s):  
Qian Qi ◽  
Mary M. Cavanagh ◽  
Sabine Le Saux ◽  
Hong NamKoong ◽  
Chulwoo Kim ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Chronic Infection ◽  
Cell Receptor ◽  
Control Mechanisms ◽  
Cell Repertoire ◽  
T Cell Clones ◽  
Varicella Zoster ◽  
Cell Clones

Diversity and size of the antigen-specific T cell receptor (TCR) repertoire are two critical determinants for successful control of chronic infection. Varicella zoster virus (VZV) that establishes latency during childhood can escape control mechanisms, in particular with increasing age. We examined the TCR diversity of VZV-reactive CD4 T cells in individuals older than 50 years by studying three identical twin pairs and three unrelated individuals before and after vaccination with live attenuated VZV. Although all individuals had a small number of dominant T cell clones, the breadth of the VZV-specific repertoire differed markedly. A genetic influence was seen for the sharing of individual TCR sequences from antigen-reactive cells but not for repertoire richness or the selection of dominant clones. VZV vaccination favored the expansion of infrequent VZV antigen–reactive TCRs, including those from naïve T cells with lesser boosting of dominant T cell clones. Thus, vaccination does not reinforce the in vivo selection that occurred during chronic infection but leads to a diversification of the VZV-reactive T cell repertoire. However, a single-booster immunization seems insufficient to establish new clonal dominance. Our results suggest that repertoire analysis of antigen-specific TCRs can be an important readout to assess whether a vaccination was able to generate memory cells in clonal sizes that are necessary for immune protection.

scholarly journals Atypical TRAV1-2− T cell receptor recognition of the antigen-presenting molecule MR1

2020 ◽  
Vol 295 (42) ◽  
pp. 14445-14457 ◽  
Author(s):  
Wael Awad ◽  
Erin W. Meermeier ◽  
Maria L. Sandoval-Romero ◽  
Jérôme Le Nours ◽  
Aneta H. Worley ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
T Cell Repertoire ◽  
Cell Repertoire ◽  
Mait Cells ◽  
Receptor Recognition ◽  
Antigen Presenting ◽  
Β Chain ◽  
Complementarity Determining Region

MR1 presents vitamin B–related metabolites to mucosal associated invariant T (MAIT) cells, which are characterized, in part, by the TRAV1-2+ αβ T cell receptor (TCR). In addition, a more diverse TRAV1-2− MR1-restricted T cell repertoire exists that can possess altered specificity for MR1 antigens. However, the molecular basis of how such TRAV1-2− TCRs interact with MR1–antigen complexes remains unclear. Here, we describe how a TRAV12-2+ TCR (termed D462-E4) recognizes an MR1–antigen complex. We report the crystal structures of the unliganded D462-E4 TCR and its complex with MR1 presenting the riboflavin-based antigen 5-OP-RU. Here, the TRBV29-1 β-chain of the D462-E4 TCR binds over the F′-pocket of MR1, whereby the complementarity-determining region (CDR) 3β loop surrounded and projected into the F′-pocket. Nevertheless, the CDR3β loop anchored proximal to the MR1 A′-pocket and mediated direct contact with the 5-OP-RU antigen. The D462-E4 TCR footprint on MR1 contrasted that of the TRAV1-2+ and TRAV36+ TCRs' docking topologies on MR1. Accordingly, diverse MR1-restricted T cell repertoire reveals differential docking modalities on MR1, thus providing greater scope for differing antigen specificities.

scholarly journals The CD4−CD8− MAIT cell subpopulation is a functionally distinct subset developmentally related to the main CD8+ MAIT cell pool

2018 ◽  
Vol 115 (49) ◽  
pp. E11513-E11522 ◽  
Author(s):  
Joana Dias ◽  
Caroline Boulouis ◽  
Jean-Baptiste Gorin ◽  
Robin H. G. A. van den Biggelaar ◽  
Kerri G. Lal ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Gene Signature ◽  
Cell Subpopulation ◽  
Bacterial Strains ◽  
Mait Cells ◽  
Receptor Repertoire ◽  
Mait Cell

Mucosa-associated invariant T (MAIT) cells are unconventional innate-like T cells that recognize microbial riboflavin metabolites presented by the MHC class I-like protein MR1. Human MAIT cells predominantly express the CD8α coreceptor (CD8+), with a smaller subset lacking both CD4 and CD8 (double-negative, DN). However, it is unclear if these two MAIT cell subpopulations distinguished by CD8α represent functionally distinct subsets. Here, we show that the two MAIT cell subsets express divergent transcriptional programs and distinct patterns of classic T cell transcription factors. Furthermore, CD8+ MAIT cells have higher levels of receptors for IL-12 and IL-18, as well as of the activating receptors CD2, CD9, and NKG2D, and display superior functionality following stimulation with riboflavin-autotrophic as well as riboflavin-auxotrophic bacterial strains. DN MAIT cells display higher RORγt/T-bet ratio, and express less IFN-γ and more IL-17. Furthermore, the DN subset displays enrichment of an apoptosis gene signature and higher propensity for activation-induced apoptosis. During development in human fetal tissues, DN MAIT cells are more mature and accumulate over gestational time with reciprocal contraction of the CD8+ subset. Analysis of the T cell receptor repertoire reveals higher diversity in CD8+ MAIT cells than in DN MAIT cells. Finally, chronic T cell receptor stimulation of CD8+ MAIT cells in an in vitro culture system supports the accumulation and maintenance of the DN subpopulation. These findings define human CD8+ and DN MAIT cells as functionally distinct subsets and indicate a derivative developmental relationship.

scholarly journals Analysis of T-Cell Receptor Repertoire in Transplantation: Fingerprint of T Cell-mediated Alloresponse

2022 ◽  
Vol 12 ◽  
Author(s):  
Guangyao Tian ◽  
Mingqian Li ◽  
Guoyue Lv
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Immune Monitoring ◽  
Antigen Specificity ◽  
Cell Repertoire ◽  
Receptor Repertoire ◽  
Cell Clones ◽  
Alloreactive T Cell

T cells play a key role in determining allograft function by mediating allogeneic immune responses to cause rejection, and recent work pointed their role in mediating tolerance in transplantation. The unique T-cell receptor (TCR) expressed on the surface of each T cell determines the antigen specificity of the cell and can be the specific fingerprint for identifying and monitoring. Next-generation sequencing (NGS) techniques provide powerful tools for deep and high-throughput TCR profiling, and facilitate to depict the entire T cell repertoire profile and trace antigen-specific T cells in circulation and local tissues. Tailing T cell transcriptomes and TCR sequences at the single cell level provides a full landscape of alloreactive T-cell clones development and biofunction in alloresponse. Here, we review the recent advances in TCR sequencing techniques and computational tools, as well as the recent discovery in overall TCR profile and antigen-specific T cells tracking in transplantation. We further discuss the challenges and potential of using TCR sequencing-based assays to profile alloreactive TCR repertoire as the fingerprint for immune monitoring and prediction of rejection and tolerance.

scholarly journals Antigen-loaded MR1 tetramers define T cell receptor heterogeneity in mucosal-associated invariant T cells

2013 ◽  
Vol 210 (11) ◽  
pp. 2305-2320 ◽  
Author(s):  
Rangsima Reantragoon ◽  
Alexandra J. Corbett ◽  
Isaac G. Sakala ◽  
Nicholas A. Gherardin ◽  
John B. Furness ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Biology ◽  
Cell Receptor ◽  
Phenotypic Characterization ◽  
Mait Cells ◽  
Invariant T Cells ◽  
Human And Mouse ◽  
Mait Cell

Mucosal-associated invariant T cells (MAIT cells) express a semi-invariant T cell receptor (TCR) α-chain, TRAV1-2–TRAJ33, and are activated by vitamin B metabolites bound by the major histocompatibility complex (MHC)–related class I–like molecule, MR1. Understanding MAIT cell biology has been restrained by the lack of reagents to specifically identify and characterize these cells. Furthermore, the use of surrogate markers may misrepresent the MAIT cell population. We show that modified human MR1 tetramers loaded with the potent MAIT cell ligand, reduced 6-hydroxymethyl-8-d-ribityllumazine (rRL-6-CH2OH), specifically detect all human MAIT cells. Tetramer+ MAIT subsets were predominantly CD8+ or CD4−CD8−, although a small subset of CD4+ MAIT cells was also detected. Notably, most human CD8+ MAIT cells were CD8α+CD8β−/lo, implying predominant expression of CD8αα homodimers. Tetramer-sorted MAIT cells displayed a TH1 cytokine phenotype upon antigen-specific activation. Similarly, mouse MR1–rRL-6-CH2OH tetramers detected CD4+, CD4−CD8− and CD8+ MAIT cells in Vα19 transgenic mice. Both human and mouse MAIT cells expressed a broad TCR-β repertoire, and although the majority of human MAIT cells expressed TRAV1-2–TRAJ33, some expressed TRAJ12 or TRAJ20 genes in conjunction with TRAV1-2. Accordingly, MR1 tetramers allow precise phenotypic characterization of human and mouse MAIT cells and revealed unanticipated TCR heterogeneity in this population.

scholarly journals Type I interferons are important co-stimulatory signals during T cell receptor mediated MAIT cell activation

2019 ◽  
Author(s):  
Rajesh Lamichhane ◽  
Henry Galvin ◽  
Rachel F Hannaway ◽  
Sara M de la Harpe ◽  
Fran Munro ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Cell Activation ◽  
Cell Receptor ◽  
Interferon Γ ◽  
Type I Interferons ◽  
Type I ◽  
Mait Cells ◽  
Mait Cell

AbstractMucosal associated invariant T (MAIT) cells are abundant unconventional T cells which can be stimulated either via their T cell receptor (TCR) or by innate cytokines. The MAIT cell TCR recognises a pyrimidine ligand, derived from riboflavin synthesising bacteria, bound to MR1. In infection, bacteria not only provide the pyrimidine ligand but also co-stimulatory signals, such as Toll-like receptor agonists, that can modulate TCR-mediated activation. Recently, type I interferons (T1-IFNs) have been identified as contributing to cytokine-mediated MAIT cell activation. However, it is unknown whether T1-IFNs also have a role during TCR-mediated MAIT cell activation. In this study, we investigated the co-stimulatory role of T1-IFNs during TCR-mediated activation of MAIT cells by the MR1 ligand 5-amino-6-D-ribitylaminouracil/methylglyoxal (5-A-RU/MG). We found that T1-IFNs were able to boost interferon-γ and granzyme B production in 5-A-RU/MG-stimulated MAIT cells. Similarly, influenza virus-induced T1-IFNs enhanced TCR-mediated MAIT cell activation. An essential role of T1-IFNs in regulating MAIT cell activation by riboflavin synthesising bacteria was also demonstrated. The co-stimulatory role of T1-IFNs was confirmed using liver-derived MAIT cells. T1-IFNs acted directly on MAIT cells to enhance their response to TCR stimulation. Overall, our findings establish an important immunomodulatory role of T1-IFNs during TCR-mediated MAIT cell activation.

scholarly journals A molecular basis underpinning the T cell receptor heterogeneity of mucosal-associated invariant T cells

2014 ◽  
Vol 211 (8) ◽  
pp. 1585-1600 ◽  
Author(s):  
Sidonia B.G. Eckle ◽  
Richard W. Birkinshaw ◽  
Lyudmila Kostenko ◽  
Alexandra J. Corbett ◽  
Hamish E.G. McWilliam ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Conformational Changes ◽  
Cell Biology ◽  
Cell Receptor ◽  
Cell Surface Expression ◽  
Dependent Manner ◽  
Gene Usage ◽  
The Impact ◽  
Mait Cell

Mucosal-associated invariant T (MAIT) cells express an invariant T cell receptor (TCR) α-chain (TRAV1-2 joined to TRAJ33, TRAJ20, or TRAJ12 in humans), which pairs with an array of TCR β-chains. MAIT TCRs can bind folate- and riboflavin-based metabolites restricted by the major histocompatibility complex (MHC)-related class I−like molecule, MR1. However, the impact of MAIT TCR and MR1-ligand heterogeneity on MAIT cell biology is unclear. We show how a previously uncharacterized MR1 ligand, acetyl-6-formylpterin (Ac-6-FP), markedly stabilized MR1, potently up-regulated MR1 cell surface expression, and inhibited MAIT cell activation. These enhanced properties of Ac-6-FP were attributable to structural alterations in MR1 that subsequently affected MAIT TCR recognition via conformational changes within the complementarity-determining region (CDR) 3β loop. Analysis of seven TRBV6-1+ MAIT TCRs demonstrated how CDR3β hypervariability impacted on MAIT TCR recognition by altering TCR flexibility and contacts with MR1 and the Ag itself. Ternary structures of TRBV6-1, TRBV6-4, and TRBV20+ MAIT TCRs in complex with MR1 bound to a potent riboflavin-based antigen (Ag) showed how variations in TRBV gene usage exclusively impacted on MR1 contacts within a consensus MAIT TCR-MR1 footprint. Moreover, differential TRAJ gene usage was readily accommodated within a conserved MAIT TCR-MR1-Ag docking mode. Collectively, MAIT TCR heterogeneity can fine-tune MR1 recognition in an Ag-dependent manner, thereby modulating MAIT cell recognition.

scholarly journals Radiation induces dynamic changes to the T cell repertoire in renal cell carcinoma patients

2020 ◽  
Vol 117 (38) ◽  
pp. 23721-23729
Author(s):  
Jacky Chow ◽  
Nicholas C. Hoffend ◽  
Scott I. Abrams ◽  
Thomas Schwaab ◽  
Anurag K. Singh ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Renal Cell ◽  
Rational Design ◽  
Cell Receptor ◽  
Cell Repertoire ◽  
Treatment Pathway ◽  
Cell Clones ◽  
Immune Mediated

Clinical studies combining radiation and immunotherapy have shown promising response rates, strengthening efforts to sensitize tumors to immune-mediated attack. Thus, there is an ongoing surge in trials using preconditioning regimens with immunotherapy. Yet, due to the scarcity of resected tumors treated in situ with radiotherapy, there has been little investigation of radiation’s sole contributions to local and systemic antitumor immunity in patients. Without this access, translational studies have been limited to evaluating circulating immune subsets and systemic remodeling of peripheral T cell receptor repertoires. This constraint has left gaps in how radiation impacts intratumoral responses and whether tumor-resident T cell clones are amplified following treatment. Therefore, to interrogate the immune impact of radiation on the tumor microenvironment and test the hypothesis that radiation initiates local and systemic expansion of tumor-resident clones, we analyzed renal cell carcinomas from patients treated with stereotactic body radiation therapy. Transcriptomic comparisons were evaluated by bulk RNA sequencing. T cell receptor sequencing monitored repertoires during treatment. Pathway analysis showed radiation-specific enrichment of immune-related processes, and T cell receptor sequencing revealed increased clonality in radiation-treated tumors. The frequency of identified, tumor-enriched clonotypes was tracked across serial blood samples. We observed increased abundance of tumor-enriched clonotypes at 2 wk postradiation compared with pretreatment levels; however, this expansion was not sustained, and levels contracted toward baseline by 4 wk posttreatment. Taken together, these results indicate robust intratumoral immune remodeling and a window of tumor-resident T cell expansion following radiation that may be leveraged for the rational design of combinatorial strategies.

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