The T-cell receptor (TCR)/CD3 complex plays an essential role in the immune response and is a key player in cancer immunotherapies. There are two classes of TCR/CD3 complexes, defined by their TCR chain usage (αβ or γδ). Recently reported structures have revealed the organization of the αβ TCR/CD3 complex, but similar studies regarding the γδ TCR/CD3 complex have lagged behind. Here, we report cryoelectron microscopy (cryoEM) structural analysis of two γδ TCRs, G115 (Vγ9 Vδ2) and 9C2 (Vγ5 Vδ1), in complex with CD3 subunits. Our results show that the overall subunit organization of the γδ TCR/CD3 complexes is similar to αβ TCRs. However, both γδ TCRs display highly mobile extracellular domains (ECDs), unlike αβ TCRs, which have TCR ECDs that are rigidly coupled to its transmembrane (TM) domains. We corroborate this finding in cells by demonstrating that a γδ T-cell specific antibody can bind a site that would be inaccessible in the more rigid αβ TCR/CD3 complex. Furthermore, we observed that the Vγ5 Vδ1 complex forms a TCR γ5 chain-mediated dimeric species whereby two TCR/CD3 complexes are assembled. Collectively, these data shed light on γδ TCR/CD3 complex formation and may aid the design of γδ TCR-based therapies.
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http://dx.doi.org/10.1038/s41467-024-55467-5 | DOI Listing |
Immunol Rev
January 2025
Signaling Research Centers BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.
Rather than being contained in a single polypeptide, and unlike receptor tyrosine kinases, the T cell receptor (TCR) divides its signaling functions among its subunits: TCRα/β bind the extracellular ligand, an antigenic peptide-MHC complex (pMHC), and the CD3 subunits (CD3γ, CD3δ, CD3ε, and CD3ζ) transmit this information to the cytoplasm. How information about the quality of pMHC binding outside is transmitted to the cytoplasm remains a matter of debate. In this review, we compile data generated using a wide variety of experimental systems indicating that TCR engagement by an appropriate pMHC triggers allosteric changes transmitted from the ligand-binding loops in the TCRα and TCRβ subunits to the cytoplasmic tails of the CD3 subunits.
View Article and Find Full Text PDFNat Commun
January 2025
Regeneron Pharmaceuticals, Inc., Tarrytown, NY, 10591, USA.
The T-cell receptor (TCR)/CD3 complex plays an essential role in the immune response and is a key player in cancer immunotherapies. There are two classes of TCR/CD3 complexes, defined by their TCR chain usage (αβ or γδ). Recently reported structures have revealed the organization of the αβ TCR/CD3 complex, but similar studies regarding the γδ TCR/CD3 complex have lagged behind.
View Article and Find Full Text PDFImmunol Rev
December 2024
Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.
αβT cells protect vertebrates against many diseases, optimizing surveillance using mechanical force to distinguish between pathophysiologic cellular alterations and normal self-constituents. The multi-subunit αβT-cell receptor (TCR) operates outside of thermal equilibrium, harvesting energy via physical forces generated by T-cell motility and actin-myosin machinery. When a peptide-bound major histocompatibility complex molecule (pMHC) on an antigen presenting cell is ligated, the αβTCR on the T cell leverages force to form a catch bond, prolonging bond lifetime, and enhancing antigen discrimination.
View Article and Find Full Text PDFFront Immunol
November 2024
Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands.
The development of T follicular helper (Tfh) cells is an ongoing process resulting in the formation of various Tfh subsets. Despite advancements, the precise impact of T cell receptor (TCR) stimulation on this process remains incompletely understood. This study explores how TCR-CD3 signaling strength influences naive CD4 T cell differentiation into Tfh-like cells and the concurrent expression of interleukin-21 (IL-21), interleukin-4 (IL-4), and interferon-gamma (IFN-γ).
View Article and Find Full Text PDFEMBO Rep
December 2024
Laura and Isaac Perlmutter Cancer Center, NYU Grossman School of Medicine, New York, NY, 10016, USA.
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