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Dual Role of CD4 in Peripheral T Lymphocytes

The interaction of T-cell receptors (TCRs) with self- and non-self-peptides in the major histocompatibility complex (MHC) stimulates crucial signaling events, which in turn can activate T lymphocytes. A variety of accessory molecules further modulate T-cell signaling. Of these, the CD4 and CD8 corec...

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Detalles Bibliográficos
Autores principales: Glatzová, Daniela, Cebecauer, Marek
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6454155/
https://www.ncbi.nlm.nih.gov/pubmed/31001252
http://dx.doi.org/10.3389/fimmu.2019.00618
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author Glatzová, Daniela
Cebecauer, Marek
author_facet Glatzová, Daniela
Cebecauer, Marek
author_sort Glatzová, Daniela
collection PubMed
description The interaction of T-cell receptors (TCRs) with self- and non-self-peptides in the major histocompatibility complex (MHC) stimulates crucial signaling events, which in turn can activate T lymphocytes. A variety of accessory molecules further modulate T-cell signaling. Of these, the CD4 and CD8 coreceptors make the most critical contributions to T cell sensitivity in vivo. Whereas, CD4 function in T cell development is well-characterized, its role in peripheral T cells remains incompletely understood. It was originally suggested that CD4 stabilizes weak interactions between TCRs and peptides in the MHC and delivers Lck kinases to that complex. The results of numerous experiments support the latter role, indicating that the CD4-Lck complex accelerates TCR-triggered signaling and controls the availability of the kinase for TCR in the absence of the ligand. On the other hand, extremely low affinity of CD4 for MHC rules out its ability to stabilize the receptor-ligand complex. In this review, we summarize the current knowledge on CD4 in T cells, with a special emphasis on the spatio-temporal organization of early signaling events and the relevance for CD4 function. We further highlight the capacity of CD4 to interact with the MHC in the absence of TCR. It drives the adhesion of T cells to the cells that express the MHC. This process is facilitated by the CD4 accumulation in the tips of microvilli on the surface of unstimulated T cells. Based on these observations, we suggest an alternative model of CD4 role in T-cell activation.
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spelling pubmed-64541552019-04-18 Dual Role of CD4 in Peripheral T Lymphocytes Glatzová, Daniela Cebecauer, Marek Front Immunol Immunology The interaction of T-cell receptors (TCRs) with self- and non-self-peptides in the major histocompatibility complex (MHC) stimulates crucial signaling events, which in turn can activate T lymphocytes. A variety of accessory molecules further modulate T-cell signaling. Of these, the CD4 and CD8 coreceptors make the most critical contributions to T cell sensitivity in vivo. Whereas, CD4 function in T cell development is well-characterized, its role in peripheral T cells remains incompletely understood. It was originally suggested that CD4 stabilizes weak interactions between TCRs and peptides in the MHC and delivers Lck kinases to that complex. The results of numerous experiments support the latter role, indicating that the CD4-Lck complex accelerates TCR-triggered signaling and controls the availability of the kinase for TCR in the absence of the ligand. On the other hand, extremely low affinity of CD4 for MHC rules out its ability to stabilize the receptor-ligand complex. In this review, we summarize the current knowledge on CD4 in T cells, with a special emphasis on the spatio-temporal organization of early signaling events and the relevance for CD4 function. We further highlight the capacity of CD4 to interact with the MHC in the absence of TCR. It drives the adhesion of T cells to the cells that express the MHC. This process is facilitated by the CD4 accumulation in the tips of microvilli on the surface of unstimulated T cells. Based on these observations, we suggest an alternative model of CD4 role in T-cell activation. Frontiers Media S.A. 2019-04-02 /pmc/articles/PMC6454155/ /pubmed/31001252 http://dx.doi.org/10.3389/fimmu.2019.00618 Text en Copyright © 2019 Glatzová and Cebecauer. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Immunology
Glatzová, Daniela
Cebecauer, Marek
Dual Role of CD4 in Peripheral T Lymphocytes
title Dual Role of CD4 in Peripheral T Lymphocytes
title_full Dual Role of CD4 in Peripheral T Lymphocytes
title_fullStr Dual Role of CD4 in Peripheral T Lymphocytes
title_full_unstemmed Dual Role of CD4 in Peripheral T Lymphocytes
title_short Dual Role of CD4 in Peripheral T Lymphocytes
title_sort dual role of cd4 in peripheral t lymphocytes
topic Immunology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6454155/
https://www.ncbi.nlm.nih.gov/pubmed/31001252
http://dx.doi.org/10.3389/fimmu.2019.00618
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