Self-discrimination, a critical but ill-defined molecular process programmed during thymocyte development, requires myriad pre-T cell receptors (preTCRs) and αβTCRs. Using x-ray crystallography, we show how a preTCR applies the concave β-sheet surface of its single variable domain (Vβ) to "horizontally" grab the protruding MHC α2-helix. By contrast, αβTCRs purpose all six complementarity-determining region (CDR) loops of their paired VαVβ module to recognize peptides bound to major histocompatibility complex molecules (pMHCs) in "vertical" head-to-head binding. The preTCR topological fit ensures that CDR3β reaches the peptide's featured C-terminal segment for pMHC sampling, establishing the subsequent αβTCR canonical docking mode. "Horizontal" docking precludes germline CDR1β- and CDR2β-MHC binding to broaden β-chain repertoire diversification before αβTCR-mediated selection refinement. Thus, one subunit successively attunes the recognition logic of related multicomponent receptors.
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http://dx.doi.org/10.1126/science.abe0918 | DOI Listing |
NPJ Genom Med
January 2025
Division of Immunology and Allergy, Department of Paediatrics, The Hospital for Sick Children and the University of Toronto, Toronto, ON, Canada.
Maturation of αβ lineage T cells in the thymus relies on the formation and cell surface expression of a pre-T cell receptor (TCR) complex, composed of TCRβ chain and pre-TCRα (pTCRα) chain heterodimers, giving rise to a diverse T cell repertoire. Genetic aberrations in key molecules involved in T cell development lead to profound T cell immunodeficiency. Definitive genetic diagnosis guides treatment choices and counseling.
View Article and Find Full Text PDFTranspl Immunol
December 2024
Department of Immunology, Institute of Hematology and Blood Transfusion, Prague, Czech Republic. Electronic address:
Background: The rate of immune reconstitution after allogeneic hematopoietic stem cell transplantation (allo-HSCT) plays the principal role in the development of serious post-transplant complications. However, the post-transplantation course has a significant impact on shaping the immune system of the recipient, per se, thus representing risk factors for subsequent unfavorable outcomes. The predictive power of an interferon gamma (IFNγ) release assay (IGRA) on graft-versus-host disease (GVHD) or hematological relapse in recipients of allo-HSCT treated with post-transplantation cyclophosphamide and the impact of these complications on the restoration of cellular immune responsiveness was evaluated.
View Article and Find Full Text PDFJ Leukoc Biol
November 2024
i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.
The pre-T cell receptor (TCR) and TCR complexes are frequently expressed in T-cell acute lymphoblastic leukemia (T-ALL), an aggressive T cell precursor malignancy. Although mutations in TCR components are infrequent in T-ALL, earlier research indicated that transgenic αβ TCR expression in mouse T cell precursors promoted T-ALL development. However, we recently found that stimulation of TCR signaling in T-ALL induced leukemic cell apoptosis and suppressed leukemia.
View Article and Find Full Text PDFAging (Albany NY)
October 2024
Department of Hematology, Handan First Hospital, Handan, Hebei 056001, China.
Background: Precursor T-cell acute lymphoblastic leukemia (Pre-T ALL) is a malignant neoplastic disease in which T-cells proliferate in the bone marrow. Single-cell sequencing technology could identify characteristic cell types, facilitating the study of the therapeutic mechanisms in Pre-T ALL.
Methods: The single-cell sequencing data (scRNA-seq) of Pre-T ALL were obtained from public databases.
Nat Immunol
September 2024
Department of Host-Microbe Interactions, St. Jude Children's Research Hospital, Memphis, TN, USA.
The differentiation and specificity of human CD4 T follicular helper cells (T cells) after influenza vaccination have been poorly defined. Here we profiled blood and draining lymph node (LN) samples from human volunteers for over 2 years after two influenza vaccines were administered 1 year apart to define the evolution of the CD4 T cell response. The first vaccination induced an increase in the frequency of circulating T (cT) and LN T cells at week 1 postvaccination.
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