Faculty Opinions recommendation of Expansion of the antigenic repertoire of a single T cell receptor upon T cell activation.

2001 ◽  
Author(s):  
David Serreze
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cell Receptor

scholarly journals T cell receptor zeta/CD3-p59fyn(T)-associated p120/130 binds to the SH2 domain of p59fyn(T).

1993 ◽  
Vol 178 (6) ◽  
pp. 2107-2113 ◽  
Author(s):  
A J da Silva ◽  
O Janssen ◽  
C E Rudd
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
T Cell Activation ◽  
Intracellular Signaling ◽  
Cell Activation ◽  
Cell Receptor ◽  
Sh2 Domain ◽  
T Complex

Intracellular signaling from the T cell receptor (TCR)zeta/CD3 complex is likely to be mediated by associated protein tyrosine kinases such as p59fyn(T), ZAP-70, and the CD4:p56lck and CD8:p56lck coreceptors. The nature of the signaling cascade initiated by these kinases, their specificities, and downstream targets remain to be elucidated. The TCR-zeta/CD3:p59fyn(T) complex has previously been noted to coprecipitate a 120/130-kD doublet (p120/130). This intracellular protein of unknown identity associates directly with p59fyn(T) within the receptor complex. In this study, we have shown that this interaction with p120/130 is specifically mediated by the SH2 domain (not the fyn-SH3 domain) of p59fyn(T). Further, based on the results of in vitro kinase assays, p120/130 appears to be preferentially associated with p59fyn(T) in T cells, and not with p56lck. Antibody reprecipitation studies identified p120/130 as a previously described 130-kD substrate of pp60v-src whose function and structure is unknown. TCR-zeta/CD3 induced activation of T cells augmented the tyrosine phosphorylation of p120/130 in vivo as detected by antibody and GST:fyn-SH2 fusion proteins. p120/130 represents the first identified p59fyn(T):SH2 binding substrate in T cells, and as such is likely to play a key role in the early events of T cell activation.

scholarly journals A homodimeric aptamer variant generated from ligand-guided selection activates T-cell receptor cluster of differentiation three complex

2020 ◽  
Author(s):  
Lina Freage ◽  
Deana Jamal ◽  
Nicole Williams ◽  
Prabodhika R. Mallikaratchy
Keyword(s):  
T Cell ◽  
Nucleic Acid ◽  
T Cell Receptor ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cell Receptor ◽  
Receptor Cluster ◽  
Pharmacokinetic Properties ◽  
Activation Potential ◽  
Cluster Of Differentiation

AbstractRecently, immunotherapeutic modalities with engineered cells and monoclonal antibodies have been effective in treating several malignancies. However, growing evidence suggests that immune-related adverse events (irAE) lead to severe and long-term side effects. Most iRAEs involve prolonged circulation of antibodies. To address this problem, nucleic acid aptamers can serve as alternative molecules to design immunotherapeutics with high functional diversity and predictable circulation times. Here, we report the first synthetic prototype consisting of DNA aptamers, which can activate T-cell receptor cluster of differentiation 3 (TCR-CD3) complex in cultured T-cells. We show that activation potential is similar to that of a monoclonal antibody (mAb) against TCR-CD3, suggesting the potential of aptamers in developing efficacious synthetic immunomodulators. The synthetic prototype of anti-TCR-CD3ε, as described herein, was designed using aptamer ZUCH-1 against TCR-CD3ε, generated by Ligand Guided Selection (LIGS). Aptamer ZUCH-1 was truncated and modified with nuclease-resistant RNA analogs to enhance stability. Several dimeric analogs with truncated and modified variants were designed with variable linker lengths to investigate the activation potential of each construct. Among them, dimeric aptamer with approximate dimensions similar to those of an antibody showed the highest T-cell-activation, suggesting the importance of optimizing linker lengths in engineering functional aptamers. The observed activation potential of dimeric aptamers shows the vast potential of aptamers in designing synthetically versatile immunomodulators with tunable pharmacokinetic properties, expanding immunotherapeutic designs with the use of nucleic acid-based ligands such as aptamers.

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 CD8β Endows CD8 with Efficient Coreceptor Function by Coupling T Cell Receptor/CD3 to Raft-associated CD8/p56lck Complexes

2001 ◽  
Vol 194 (10) ◽  
pp. 1485-1495 ◽  
Author(s):  
Alexandre Arcaro ◽  
Claude Grégoire ◽  
Talitha R. Bakker ◽  
Lucia Baldi ◽  
Martin Jordan ◽  
...  
Keyword(s):  
T Cell ◽  
Ligand Binding ◽  
T Cell Receptor ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cell Activation ◽  
Cell Receptor ◽  
High Affinity ◽  
Histocompatibility Complex ◽  
Peptide Derivative

The extraordinary sensitivity of CD8+ T cells to recognize antigen impinges to a large extent on the coreceptor CD8. While several studies have shown that the CD8β chain endows CD8 with efficient coreceptor function, the molecular basis for this is enigmatic. Here we report that cell-associated CD8αβ, but not CD8αα or soluble CD8αβ, substantially increases the avidity of T cell receptor (TCR)-ligand binding. To elucidate how the cytoplasmic and transmembrane portions of CD8β endow CD8 with efficient coreceptor function, we examined T1.4 T cell hybridomas transfected with various CD8β constructs. T1.4 hybridomas recognize a photoreactive Plasmodium berghei circumsporozoite (PbCS) peptide derivative (PbCS (4-azidobezoic acid [ABA])) in the context of H-2Kd, and permit assessment of TCR-ligand binding by TCR photoaffinity labeling. We find that the cytoplasmic portion of CD8β, mainly due to its palmitoylation, mediates partitioning of CD8 in lipid rafts, where it efficiently associates with p56lck. In addition, the cytoplasmic portion of CD8β mediates constitutive association of CD8 with TCR/CD3. The resulting TCR-CD8 adducts exhibit high affinity for major histocompatibility complex (MHC)-peptide. Importantly, because CD8αβ partitions in rafts, its interaction with TCR/CD3 promotes raft association of TCR/CD3. Engagement of these TCR/CD3-CD8/lck adducts by multimeric MHC-peptide induces activation of p56lck in rafts, which in turn phosphorylates CD3 and initiates T cell activation.

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