scholarly journals T Cell Receptor Non-Equilibrium Kinetics

2021 ◽  
Author(s):  
Zachary A Rollins ◽  
Roland Faller ◽  
Steven Carl George
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Constant Load ◽  
T Cell Response ◽  
Atomic Scale ◽  
Dynamic Simulations ◽  
Immunogenic Peptides ◽  
Binding Groove

An atomic-scale mechanism describing the role of mechanosensing in T Cell Receptor (TCR) recognition of peptides in the binding groove of the peptide-major histocompatibility complex (pMHC) may inform the design of novel TCRs for immunotherapies. Using steered molecular dynamic simulations, our study demonstrates that mutations to peptides in the binding groove of the pMHC -- which are known to discretely alter the T cell response to an antigen -- influence MHC conformation and thus the overall strength of the TCR-pMHC bond including duration and length under constant load. Moreover, physiochemical features of the TCR-pMHC dynamic bond strength, such as hydrogen bonds and Lennard-Jones contacts, correlate with the immunogenic response elicited by the specific peptide in the MHC groove. Thus, formation of transient TCR-pMHC bonds is a characteristic of immunogenic peptides and is mediated by stabilized interactions.

scholarly journals Diacylglycerol Kinase alpha in X Linked Lymphoproliferative Disease Type 1

2021 ◽  
Vol 22 (11) ◽  
pp. 5816
Author(s):  
Suresh Velnati ◽  
Sara Centonze ◽  
Federico Girivetto ◽  
Gianluca Baldanzi
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Adaptor Protein ◽  
Diacylglycerol Kinase ◽  
Cell Receptor ◽  
Lymphoproliferative Disease ◽  
Disease Type ◽  
T Cell Response ◽  
Receptor Signalling

Diacylglycerol kinases are intracellular enzymes that control the balance between the secondary messengers diacylglycerol and phosphatidic acid. DGKα and DGKζ are the prominent isoforms that restrain the intensity of T cell receptor signalling by metabolizing PLCγ generated diacylglycerol. Thus, their activity must be tightly controlled to grant cellular homeostasis and refine immune responses. DGKα is specifically inhibited by strong T cell activating signals to allow for full diacylglycerol signalling which mediates T cell response. In X-linked lymphoproliferative disease 1, deficiency of the adaptor protein SAP results in altered T cell receptor signalling, due in part to persistent DGKα activity. This activity constrains diacylglycerol levels, attenuating downstream pathways such as PKCθ and Ras/MAPK and decreasing T cell restimulation induced cell death. This is a form of apoptosis triggered by prolonged T cell activation that is indeed defective in CD8+ cells of X-linked lymphoproliferative disease type 1 patients. Accordingly, inhibition or downregulation of DGKα activity restores in vitro a correct diacylglycerol dependent signal transduction, cytokines production and restimulation induced apoptosis. In animal disease models, DGKα inhibitors limit CD8+ expansion and immune-mediated tissue damage, suggesting the possibility of using inhibitors of diacylglycerol kinase as a new therapeutic approach.

scholarly journals Ceramide Synthase 2 Null Mice Are Protected from Ovalbumin-Induced Asthma with Higher T Cell Receptor Signal Strength in CD4+ T Cells

2021 ◽  
Vol 22 (5) ◽  
pp. 2713
Author(s):  
Sun-Hye Shin ◽  
Kyung-Ah Cho ◽  
Hee-Soo Yoon ◽  
So-Yeon Kim ◽  
Hee-Yeon Kim ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cd4 T Cells ◽  
Acyl Chain ◽  
Signal Strength ◽  
Cell Receptor ◽  
Ceramide Synthase ◽  
Asthmatic Patients

(1) Background: six mammalian ceramide synthases (CerS1–6) determine the acyl chain length of sphingolipids (SLs). Although ceramide levels are increased in murine allergic asthma models and in asthmatic patients, the precise role of SLs with specific chain lengths is still unclear. The role of CerS2, which mainly synthesizes C22–C24 ceramides, was investigated in immune responses elicited by airway inflammation using CerS2 null mice. (2) Methods: asthma was induced in wild type (WT) and CerS2 null mice with ovalbumin (OVA), and inflammatory cytokines and CD4 (cluster of differentiation 4)+ T helper (Th) cell profiles were analyzed. We also compared the functional capacity of CD4+ T cells isolated from WT and CerS2 null mice. (3) Results: CerS2 null mice exhibited milder symptoms and lower Th2 responses than WT mice after OVA exposure. CerS2 null CD4+ T cells showed impaired Th2 and increased Th17 responses with concomitant higher T cell receptor (TCR) signal strength after TCR stimulation. Notably, increased Th17 responses of CerS2 null CD4+ T cells appeared only in TCR-mediated, but not in TCR-independent, treatment. (4) Conclusions: altered Th2/Th17 immune response with higher TCR signal strength was observed in CerS2 null CD4+ T cells upon TCR stimulation. CerS2 and very-long chain SLs may be therapeutic targets for Th2-related diseases such as asthma.

scholarly journals The Role of Molecular Flexibility in Antigen Presentation and T Cell Receptor-Mediated Signaling

2018 ◽  
Vol 9 ◽  
Author(s):  
Kannan Natarajan ◽  
Jiansheng Jiang ◽  
Nathan A. May ◽  
Michael G. Mage ◽  
Lisa F. Boyd ◽  
...  
Keyword(s):  
T Cell ◽  
Antigen Presentation ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Molecular Flexibility

CD4+ T cells specific for glycoprotein B from cytomegalovirus exhibit extreme conservation of T-cell receptor usage between different individuals

Blood ◽  
2008 ◽  
Vol 111 (4) ◽  
pp. 2053-2061 ◽  
Author(s):  
Laura Crompton ◽  
Naeem Khan ◽  
Rajiv Khanna ◽  
Laxman Nayak ◽  
Paul A. H. Moss
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Response ◽  
Cd4 T Cells ◽  
Clonal Selection ◽  
Cell Receptor ◽  
T Cell Response ◽  
Cd4 T Cell ◽  
Extreme Conservation

Antigen-specific CD8+ cytotoxic T cells often demonstrate extreme conservation of T-cell receptor (TCR) usage between different individuals, but similar characteristics have not been documented for CD4+ T cells. CD4+ T cells predominantly have a helper immune role, but a cytotoxic CD4+ T-cell subset has been characterized, and we have studied the cytotoxic CD4+ T-cell response to a peptide from human cytomegalovirus glycoprotein B presented through HLA-DRB*0701. We show that this peptide elicits a cytotoxic CD4+ T-cell response that averages 3.6% of the total CD4+ T-cell repertoire of cytomegalovirus-seropositive donors. Moreover, CD4+ cytotoxic T-cell clones isolated from different individuals exhibit extensive conservation of TCR usage, which indicates strong T-cell clonal selection for peptide recognition. Remarkably, this TCR sequence was recently reported in more than 50% of cases of CD4+ T-cell large granular lymphocytosis. Immunodominance of cytotoxic CD4+ T cells thus parallels that of CD8+ subsets and suggests that cytotoxic effector function is critical to the development of T-cell clonal selection, possibly from immune competition secondary to lysis of antigen-presenting cells. In addition, these TCR sequences are highly homologous to those observed in HLA-DR7+ patients with CD4+ T-cell large granular lymphocytosis and implicate cytomegalovirus as a likely antigenic stimulus for this disorder.

scholarly journals T Cell Receptor Specificity Is Critical for the Development of Epidermal γδ T Cells

2001 ◽  
Vol 194 (10) ◽  
pp. 1473-1483 ◽  
Author(s):  
Isabel Ferrero ◽  
Anne Wilson ◽  
Friedrich Beermann ◽  
Werner Held ◽  
H. Robson MacDonald
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Biology ◽  
Γδ T Cells ◽  
Cell Receptor ◽  
Wild Type ◽  
Normal Numbers ◽  
T Cell Biology

A particular feature of γδ T cell biology is that cells expressing T cell receptor (TCR) using specific Vγ/Vδ segments are localized in distinct epithelial sites, e.g., in mouse epidermis nearly all γδ T cells express Vγ3/Vδ1. These cells, referred to as dendritic epidermal T cells (DETC) originate from fetal Vγ3+ thymocytes. The role of γδ TCR specificity in DETC's migration/localization to the skin has remained controversial. To address this issue we have generated transgenic (Tg) mice expressing a TCR δ chain (Vδ6.3-Dδ1-Dδ2-Jδ1-Cδ), which can pair with Vγ3 in fetal thymocytes but is not normally expressed by DETC. In wild-type (wt) Vδ6.3Tg mice DETC were present and virtually all of them express Vδ6.3. However, DETC were absent in TCR-δ−/− Vδ6.3Tg mice, despite the fact that Vδ6.3Tg γδ T cells were present in normal numbers in other lymphoid and nonlymphoid tissues. In wt Vδ6.3Tg mice, a high proportion of in-frame Vδ1 transcripts were found in DETC, suggesting that the expression of an endogenous TCR-δ (most probably Vδ1) was required for the development of Vδ6.3+ epidermal γδ T cells. Collectively our data demonstrate that TCR specificity is essential for the development of γδ T cells in the epidermis. Moreover, they show that the TCR-δ locus is not allelically excluded.

scholarly journals Generation of diversity in T cell receptor repertoire specific for pigeon cytochrome c.

1987 ◽  
Vol 165 (2) ◽  
pp. 279-301 ◽  
Author(s):  
S B Sorger ◽  
S M Hedrick ◽  
P J Fink ◽  
M A Bookman ◽  
L A Matis
Keyword(s):  
T Cell ◽  
Cytochrome C ◽  
T Cell Receptor ◽  
Cell Lines ◽  
Dna Sequences ◽  
Cell Receptor ◽  
T Cell Response ◽  
Beta Chain ◽  
Antigen Specificity ◽  
T Cell Lines

17 T cell clones and 3 T cell lines, specific for pigeon cytochrome c, were analyzed for fine specificity and rearranged T cell receptor (TCR) gene elements. Clones of similar fine specificities were grouped into one of four phenotypes, and correlations between phenotype differences and gene usage could be made. All the lines and clones rearranged a member of the V alpha 2B4 gene family to a limited number of J alpha regions. The beta chain was made up of one of three non-cross-hybridizing V beta regions, each rearranging to only one or two J beta s. The use of alternate V beta regions could be correlated with phenotype differences, which were manifested either as MHC- or MHC and antigen-specificity changes. In addition, the presence of alloreactivity, which defined a phenotype difference, could be correlated solely with the use of an alternate J alpha region. These observations were substantiated by prospective analyses of pigeon cytochrome c-specific T cell lines that were selected for alternate MHC specificity or alloreactivity and were found to express the correlated alpha and beta chain rearrangements. Previously, the TCR DNA sequences from two clones, each representing a variant of one phenotype, showed sequence differences only in the N regions of their TCR genes. Since only these two variants, using identical V alpha-J alpha and V beta-J beta gene elements, were repeatedly observed in this study, we would predict that the junctional diversity differences are selectable. In this T cell response, all the gene elements involved in the generation of diversity appear to be selected, and may therefore be important in the determination of TCR specificity. This high degree of receptor gene selection represents a fundamental difference from the diversity seen in several extensively analyzed antibody responses.

Cross-recognition of HLA DR4 alloantigen by virus-specific CD8+ T cells: a new paradigm for self-/nonself-recognition

Blood ◽  
2009 ◽  
Vol 114 (11) ◽  
pp. 2244-2253 ◽  
Author(s):  
Michael Rist ◽  
Corey Smith ◽  
Melissa J. Bell ◽  
Scott R. Burrows ◽  
Rajiv Khanna
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cd8 T Cells ◽  
Allograft Rejection ◽  
Functional Characterization ◽  
Cell Receptor ◽  
T Cell Response ◽  
Cell Repertoire ◽  
Diverse Range

Abstract The ability of CD8+ T cells to engage a diverse range of peptide–major histocompatibility complex (MHC) complexes can also lead to cross-recognition of self and nonself peptide-MHC complexes and thus directly contribute toward allograft rejection or autoimmunity. Here we present a novel form of cross-recognition by herpes virus–specific CD8+ cytotoxic T cells that challenges the current paradigm of self/non-self recognition. Functional characterization of a human leukocyte antigen (HLA) Cw*0602-restricted cytomegalovirus-specific CD8+ T-cell response revealed an unusual dual specificity toward a pp65 epitope and the alloantigen HLA DR4. This cross-recognition of HLA DR4 alloantigen was critically dependent on the coexpression of HLA DM and was preferentially directed toward the B-cell lineage. Furthermore, allostimulation of peripheral blood lymphocytes with HLA DRB*0401-expressing cells rapidly expanded CD8+ T cells, which recognized the pp65 epitope in the context of HLA Cw*0602. T-cell repertoire analysis revealed 2 dominant populations expressing T-cell receptor beta variable (TRBV)4-3 or TRBV13, with cross-reactivity exclusively mediated by the TRBV13+ clonotypes. More importantly, cross-reactive TRBV13+ clonotypes displayed markedly lower T-cell receptor binding affinity and a distinct pattern of peptide recognition, presumably mimicking a structure presented on the HLA DR4 allotype. These results illustrate a novel mechanism whereby virus-specific CD8+ T cells can cross-recognize HLA class II molecules and may contribute toward allograft rejection and/or autoimmunity.

Sign in / Sign up

Export Citation Format

Share Document