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Published on: February 28, 2019
T cell signal transduction and the role of CD7 in costimulation
1Laboratory of Lymphocyte Biology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Insights
The T cell receptor (TCR) and coreceptors like CD28 and CD7 are crucial for initiating T cell activation and immune responses. Understanding their signaling pathways is key to modulating immune cell function.
Area of Science:
- Immunology
- Cellular Signaling
- Molecular Biology
Background:
- Mammalian immune responses involve complex cellular interactions, including receptor/ligand binding, signal transduction, and transcriptional activation.
- While the T cell receptor (TCR)-CD3 complex is vital for T cell activation, it requires additional coreceptor signals for effective immune responses.
- Coreceptors such as CD4, CD8, and CD28, along with CD7, play significant roles in initiating and amplifying T cell activation.
Purpose of the Study:
- To review the signaling pathways initiated by the TCR, CD28, and CD7.
- To discuss the functional consequences of signal transduction through these key T cell receptors.
Main Methods:
- Review of existing literature on T cell signaling pathways.
- Analysis of molecular mechanisms involving kinases, phosphatases, and subcellular localization.
- Examination of functional outcomes of T cell activation.
Main Results:
- TCR-CD3 signaling alone is insufficient for T cell transcriptional activation and effective immune response.
- CD28 and CD7 act as crucial costimulatory molecules, enhancing T cell activation.
- CD7, a member of the immunoglobulin superfamily, induces tyrosine and lipid kinase activities.
Conclusions:
- Signal transduction through TCR, CD28, and CD7 collectively orchestrates T cell activation.
- Understanding these pathways is essential for comprehending and potentially manipulating immune responses.
Abstract:
The complex cellular interactions that govern the mammalian immune response are now known to include specific receptor/ligand interactions, recruitment of intracellular signaling molecules, activation of both kinases and phosphatases, and redistribution of macromolecular complexes into specific subcellular membrane locations that, in aggregate, result in transcriptional activation. While the TCR-CD3 signal is critical for activation of the resting T cell, it alone is not sufficient to initiate transcriptional activation or generate an effective immune response. A number of other coreceptor molecules, including CD4, CD8, and CD28, have now been characterized that also play important roles in initiating or amplifying the activation of the T cell. A 40 kDa member of the immunoglobulin superfamily, the CD7 molecule, has also been shown to have costimulatory activity and to induce tyrosine and lipid kinase activities. Here we will review the signaling pathways initiated by TCR, CD28, and CD7, as well as the functional consequences of signal transduction through these receptors.
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