scholarly journals Height, but not binding epitope, affects the potency of synthetic TCR agonists

2021 ◽  
Author(s):  
Kiera B. Wilhelm ◽  
Shumpei Morita ◽  
Darren B. McAffee ◽  
Sungi Kim ◽  
Mark K. O'Dair ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Antibody Fragment ◽  
Design Parameters ◽  
Human Patient ◽  
Natural Ligand ◽  
Binding Epitope ◽  
Activation Profile

Under physiological conditions, peptide-MHC (pMHC) molecules can trigger T-cell receptors (TCRs) as monovalent ligands, sparsely distributed on the plasma membrane of an antigen-presenting cell. TCR can also be activated by artificial clustering, such as with pMHC tetramers or antibodies; however, these strategies circumvent many of the natural ligand discrimination mechanisms of the T cell and can elicit non-physiological signaling activity. We have recently introduced a synthetic TCR agonist composed of an anti-TCRβ Fab′ antibody fragment covalently bound to a DNA oligonucleotide, which serves as a membrane anchor. This Fab′-DNA ligand efficiently activates TCR as a monomer when membrane-associated and exhibits a potency and activation profile resembling agonist pMHC. In this report, we explore the geometric requirements for effective TCR triggering and cellular activation by Fab′-DNA ligands. We find that T cells are insensitive to the ligand binding epitope on the TCR complex, but that length of the DNA tether is important. Increasing the intermembrane distance spanned by Fab′-DNA:TCR complexes decreases TCR triggering efficiency and T cell activation potency. These results establish design parameters for construction of synthetic TCR agonists that are able to activate polyclonal T cell populations, such as T cells from a human patient, in a similar manner as the native pMHC ligand.

scholarly journals Impaired miRNA degradation by post-transcriptional addition of 3’ cytosine and adenine in T cell activation

2020 ◽  
Author(s):  
Ana Rodríguez-Galán ◽  
Sara G Dosil ◽  
Manuel José Gómez ◽  
Irene Fernández-Delgado ◽  
Fátima Sánchez-Cabo ◽  
...  
Keyword(s):  
T Cells ◽  
Next Generation Sequencing ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Short Term ◽  
Individual Mirnas ◽  
Activation Profile ◽  
Mirna Degradation ◽  
Generation Sequencing

ABSTRACTMiRNA repertoire of T cells undergoes extensive changes in response to activation. Whereas global miRNA downregulation occurs few hours after activation, some individual miRNAs are specifically up- or down-regulated. In this study, we have assessed miRNA expression and post-transcriptional modification kinetics in human primary CD4+ T cells upon short-term stimulation with αCD3αCD28 or IFN I using Next Generation Sequencing. Multiple miRNAs not related before with T cell activation profile have been identified as differentially expressed. Downregulated miRNAs presented higher 3’ uridylation. Dis3L2 and Eri1 (3’ to 5’ exoribonucleases that prefer uridylated RNA as substrates) increased their expression upon TCR stimulation, probably generating an adverse environment for miRNAs. Remarkably, non-templated cytosine additions to 3’ end, previously unknown to be a relevant post-transcriptional modification mechanism, were overrepresented in upregulated miRNAs, together with high levels of adenylation. In the midst of an increasing presence of exoribonucleases, miRNAs multiplying their levels may successfully escape degradation due to 3’ cytosine and adenine addition. These protective signals open a new avenue to improve miRNA stability for therapy in T cells.

scholarly journals T Cell Activation by Antibody-Like Immunoreceptors: The Position of the Binding Epitope within the Target Molecule Determines the Efficiency of Activation of Redirected T Cells

2007 ◽  
Vol 178 (7) ◽  
pp. 4650-4657 ◽  
Author(s):  
Andreas A. Hombach ◽  
Verena Schildgen ◽  
Claudia Heuser ◽  
Ricarda Finnern ◽  
David E. Gilham ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Target Molecule ◽  
Binding Epitope

Rituximab Directly Decreases T Cell Activation, Both In Vivo and In Vitro

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3935-3935 ◽  
Author(s):  
Tamar Katz ◽  
Dina Stroopinsky ◽  
Jacob M. Rowe ◽  
Irit Avivi
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
T Cell Activation ◽  
Inflammatory Cytokine ◽  
Cell Activation ◽  
Cell Function ◽  
Activation Profile

Abstract Abstract 3935 Rituximab, a chimeric anti-C20 monoclonal antibody, has been extensively used over the last decade for the therapy of B cell malignancies. Recent clinical data suggest that rituximab may affect T cell function, increasing the risk of T cell dependent infections in heavily-treated patients. The current study was designed to investigate the effect of rituximab on T cell activation and assess T cell function following the addition of rituximab to purified T cells. The T cell activation profile, dependent on rituximab administration, was evaluated in vivo and in vitro. Peripheral blood mononuclear cells (PBMCs) generated from B-cell non-Hodgkin lymphoma (NHL) patients prior and immediately after the administration of 375 mg/m2 rituximab, were examined for the expression of inflammatory cytokines. The in vitro studies were performed by using CD25 depleted PBMCs or B cell depleted T cells (CD3+CD25-CD19-). The obtained cells were stimulated with allogeneic dendritic cells (DCs), in the absence or presence or 2 mg/ml rituximab. T cell activation was evaluated using immunophenotypic markers, cytokine profile and T cell proliferation assay. Eight NHL patients participated in the study. The level of T cells expressing inflammatory cytokines was significantly decreased following the administration of a single dose of rituximab. T cells expressing IL-2 declined from a mean level of 26.5% to 11.5% and the level of IFN- γ decreased from 22% to 4.2%. Further administration of rituximab, up to 4 weekly doses, resulted in an additional decline in the amount of inflammatory cytokine producing T cells to a level of 1.4% for IL-2 and 3.5% for IFN-g. However, repeated evaluation, performed at 4 months after completing rituximab, showed restoration of the inflammatory population. In accord with this inhibitory effect, in vitro stimulation of T cells with allogeneic DCs, in the presence of rituximab, resulted in a significant decrease in activation markers (CD25, GITR and CTLA-4) (Table 1). These changes were accompanied by a marked reduction in inflammatory cytokine production and proliferative capacity. Of interest, these inhibitory effects were also obtained whilst using B cell depleted T cells (CD3+CD25-CD19-). In conclusion, rituximab administration results in a transient T cell inactivation, demonstrated through the reduction in inflammatory cytokine production and T cell proliferation capacity. This effect appears to be non-B cell dependent, being obtained in the absence of B cell in the culture, and may account for clinical observations in ameliorating T-cell dependent disorders, such as graft-versus-host disease. Table 1. Activation profile depending on rituximab (in vitro) Without rituximab With rituximab *Activation marker (%) CD25 27 9 GITR 15.6 4.7 CTLA4 17.7 7 *Cytokines expression (%) IL-2 22 2 IL12 16 4 IFN-gamma 21 1.8 T cells proliferation (O.D.) DC stimulation 1.528 0.580 CMV stimulation 1.563 0.570 anti CD3/CD28 stimulation 0.705 0.407 * Gated out of lymphocytes Disclosures: No relevant conflicts of interest to declare.

scholarly journals Temporal analysis of T-cell receptor-imposed forces via quantitative single molecule FRET measurements

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Janett Göhring ◽  
Florian Kellner ◽  
Lukas Schrangl ◽  
René Platzer ◽  
Enrico Klotzsch ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lipid Bilayers ◽  
T Cell Activation ◽  
Single Molecule ◽  
Cell Activation ◽  
Antibody Fragment ◽  
Temporal Analysis ◽  
Single Chain ◽  
Single Chain Antibody

AbstractMechanical forces acting on ligand-engaged T-cell receptors (TCRs) have previously been implicated in T-cell antigen recognition, yet their magnitude, spread, and temporal behavior are still poorly defined. We here report a FRET-based sensor equipped either with a TCR-reactive single chain antibody fragment or peptide-loaded MHC, the physiological TCR-ligand. The sensor was tethered to planar glass-supported lipid bilayers (SLBs) and informed most directly on the magnitude and kinetics of TCR-imposed forces at the single molecule level. When confronting T-cells with gel-phase SLBs we observed both prior and upon T-cell activation a single, well-resolvable force-peak of approximately 5 pN and force loading rates on the TCR of 1.5 pN per second. When facing fluid-phase SLBs instead, T-cells still exerted tensile forces yet of threefold reduced magnitude and only prior to but not upon activation.

Selective blockade of CD28 and not CTLA-4 with a single-chain Fv–α1-antitrypsin fusion antibody

Blood ◽  
2003 ◽  
Vol 102 (2) ◽  
pp. 564-570 ◽  
Author(s):  
Bernard Vanhove ◽  
Geneviève Laflamme ◽  
Flora Coulon ◽  
Marie Mougin ◽  
Patricia Vusio ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Antibody Fragment ◽  
Single Chain ◽  
Selective Blockade ◽  
Mhc Molecules ◽  
Single Chain Fv

Abstract B7-1 and B7-2 are costimulatory molecules expressed on antigen-presenting cells. The CD28/B7 costimulation pathway is critical for T-cell activation, proliferation, and Th polarization. Blocking both cytotoxic T-lymphocyte–associated antigen 4 (CTLA-4) and CD28 interactions with a CTLA-4/Ig fusion protein inhibits various immune-mediated processes in vivo, such as allograft rejection and autoimmunity. However, selective blockade of CD28 may represent a better strategy for immunosuppression than B7 blockade, because CTLA-4/B7 interactions have been shown to participate in the extinction of the T-cell receptor–mediated activation signal and to be required for the induction of immunologic tolerance. In addition, selective CD28 inhibition specifically decreases the activation of alloreactive and autoreactive T cells, but not the activation of T cells stimulated by exogenous antigens presented in the context of self major histocompatibility complex (MHC) molecules. CD28 blockade cannot be obtained with anti-CD28 dimeric antibodies, which cluster their target and promote T-cell costimulation, whereas monovalent Fab fragments can block CD28 and reduce alloreactivity. In this study, we report the construction of a monovalent single-chain Fv antibody fragment from a high-affinity antihuman CD28 antibody (CD28.3) that blocked adhesion of T cells to cells expressing the CD28 receptor CD80. Genetic fusion with the long-lived serum protein α1-antitrypsin led to an extended half-life without altering its binding characteristics. The anti-CD28 fusion molecule showed biologic activity as an immuno-suppressant by inhibiting T-cell activation and proliferation in a mixed lymphocyte reaction.

scholarly journals Temporal Analysis of T-Cell Receptor-Imposed Forces via Quantitative Single Molecule FRET Measurements

2020 ◽  
Author(s):  
Janett Göhring ◽  
Florian Kellner ◽  
Lukas Schrangl ◽  
René Platzer ◽  
Enrico Klotzsch ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lipid Bilayers ◽  
T Cell Activation ◽  
Single Molecule ◽  
Cell Activation ◽  
Antibody Fragment ◽  
Antigen Recognition ◽  
Single Chain ◽  
Single Chain Antibody

ABSTRACTMechanical forces acting on ligand-engaged T-cell receptors (TCRs) have previously been implicated in T-cell antigen recognition, yet their magnitude, spread, and temporal behavior are still poorly defined. We here report a FRET-based sensor equipped with a TCR-reactive single chain antibody fragment, which was tethered to planar supported lipid bilayers (SLBs) and informs most directly on the magnitude and kinetics of TCR-imposed forces at the single molecule level. When confronting T-cells with gel-phase SLBs we observed both prior and upon T-cell activation a single, well-resolvable force-peak of approximately 5 pN and force loading rates on the TCR of 1.5 pN per second. When facing fluid SLBs instead, T-cells still exerted tensile forces yet with threefold reduced magnitude and only prior to but not upon activation. Our findings do not only provide first truly molecular information on TCR-imposed forces within the immunological synapse, they also recalibrate their significance in antigen recognition.

scholarly journals 658 CD8 T cell activation in cancer is comprised of two distinct phases

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A686-A686
Author(s):  
Nataliya Prokhnevska ◽  
Maria Cardenas ◽  
Rajesh Valanparambil ◽  
Ewelina Sobierajska ◽  
Caroline Jansen ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cell Biology ◽  
Cell Activation ◽  
Cd8 T Cell ◽  
Human Patient

BackgroundCD8 T cell are a crucial part of the immune response to tumors, with CD8 infiltration predicting disease progression in numerous cancer types. Recently two subsets of CD8 T cells that respond to tumors have been described, a stem-like (TCF1+) CD8 T cell that can give rise to a more cytotoxic terminally differentiated (TD) (TCF1-Tim3+) CD8 T cell. In this study we aimed to understand the origin of stem-like TCF1+ CD8 T cells within tumors.MethodsHuman patient TDLN and tumor samples from kidney and prostate cancer were processed after resection and used for flow cytometry, RNA-seq, TCR-seq and whole genome DNA methylation analysis. We also used a prostate cancer mouse model that expresses the LCMV GP protein (TRAMPC1-LCMV-GP) to track tumor-specific CD8 T cells in both TDLNs and tumors.ResultsWe studied human prostate and kidney cancer tumor-draining lymph nodes (TDLN) and found that CD8 T cells are activated but fail to acquire an effector phenotype within the TDLN. Instead, they share functional, transcriptional, and epigenetic traits with stem-like cells in the tumor. We also found that activated CD8 T cells from TDLNs shared TCR overlap with both CD8 subsets within tumors. This suggests that these activated cells are a precursor to the stem-like CD8 T cells in tumors. To further test this hypothesis, we used our TRAMPC1-LCMV-GP tumor model to study tumor-specific CD8 T cell activation. We found that CD8 T cells are activated in TDLNs but fail to acquire an effector program. These cells then establish the stem-like CD8s within tumor where they require additional co-stimulation from antigen presenting cells to differentiate into TCF1- TD CD8 T cells. This is strikingly different from canonical CD8 T cell activation to acute viruses, where the effector program is acquired immediately. We also showed that human stem-like CD8 T cells require co-stimulation and TCR stimulation to divide and differentiate into terminally differentiated CD8s in-vitro, and DCs from autologous tumors can also induce this differentiation.ConclusionsOverall this work shows a model of CD8 T cell activation in response to tumors that has two distinct phases. The first occurs in the TDLN where CD8 T cells are initially activated, the second occurs in the tumor where CD8 T cells acquire an effector function after additional co-stimulation. This model of T cell differentiation adds to our understanding of basic CD8 T cell biology and has important implications to improve our current immunotherapies.

scholarly journals Probiotic supplementation reduces inflammatory profiles but does not prevent oral immune perturbations during SIV infection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rhianna Jones ◽  
Kyle Kroll ◽  
Courtney Broedlow ◽  
Luca Schifanella ◽  
Scott Smith ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
Rhesus Macaques ◽  
Oral Microbiome ◽  
Probiotic Supplementation ◽  
Siv Infection ◽  
Anti Inflammatory

AbstractHIV/SIV infections lead to massive loss of mucosal CD4 + T cells and breakdown of the epithelial mucosa resulting in severe microbial dysbiosis and chronic immune activation that ultimately drive disease progression. Moreover, disruption of one of the most understudied mucosal environments, the oral cavity, during HIV-induced immunosuppression results in significant microbial and neoplastic co-morbidities and contributes to and predicts distal disease complications. In this study we evaluated the effects of oral probiotic supplementation (PBX), which can stimulate and augment inflammatory or anti-inflammatory pathways, on early SIV infection of rhesus macaques. Our study revealed that similar to the GI mucosae, oral CD4 + T cells were rapidly depleted, and as one of the first comprehensive analyses of the oral microflora in SIV infection, we also observed significant modulation among two genera, Porphyromonas and Actinobacillus, early after infection. Interestingly, although PBX therapy did not substantially protect against oral dysbiosis or ameliorate cell loss, it did somewhat dampen inflammation and T cell activation. Collectively, these data provide one of the most comprehensive evaluations of SIV-induced changes in oral microbiome and CD4 + T cell populations, and also suggest that oral PBX may have some anti-inflammatory properties in lentivirus infections.

scholarly journals Controlling T cells spreading, mechanics and activation by micropatterning

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anaïs Sadoun ◽  
Martine Biarnes-Pelicot ◽  
Laura Ghesquiere-Dierickx ◽  
Ambroise Wu ◽  
Olivier Théodoly ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Young Modulus ◽  
Careful Examination ◽  
Adhesion Receptor ◽  
Force Microscopy ◽  
Atomic Force ◽  
Micro Patterns

AbstractWe designed a strategy, based on a careful examination of the activation capabilities of proteins and antibodies used as substrates for adhering T cells, coupled to protein microstamping to control at the same time the position, shape, spreading, mechanics and activation state of T cells. Once adhered on patterns, we examined the capacities of T cells to be activated with soluble anti CD3, in comparison to T cells adhered to a continuously decorated substrate with the same density of ligands. We show that, in our hand, adhering onto an anti CD45 antibody decorated surface was not affecting T cell calcium fluxes, even adhered on variable size micro-patterns. Aside, we analyzed the T cell mechanics, when spread on pattern or not, using Atomic Force Microscopy indentation. By expressing MEGF10 as a non immune adhesion receptor in T cells we measured the very same spreading area on PLL substrates and Young modulus than non modified cells, immobilized on anti CD45 antibodies, while retaining similar activation capabilities using soluble anti CD3 antibodies or through model APC contacts. We propose that our system is a way to test activation or anergy of T cells with defined adhesion and mechanical characteristics, and may allow to dissect fine details of these mechanisms since it allows to observe homogenized populations in standardized T cell activation assays.

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