Related Experiment Video
Updated: Aug 8, 2026

Qualitative and Quantitative Analysis of the Immune Synapse in the Human System Using Imaging Flow Cytometry
Published on: January 7, 2019
CD5 inhibits signaling at the immunological synapse without impairing its formation
Cédric Brossard1, Monique Semichon, Alain Trautmann
1Département de Biologie Cellulaire, Institut National de la Santé et de la Recherche Médicale, Unité 567, Center National de la Recherche Scientifique, Unité Mixte de Recherche 8104, Université René Descartes, Institut Cochin, Paris, France.
Abstract:
Physiologically, Ag detection by T cells occurs at the immunological synapse (IS) formed at the interface with an APC. CD5 is considered as an inhibitory molecule for Ag receptor-mediated signals in T cells. However, the influence of CD5 at the IS on synapse formation and functioning has not yet been reported. We demonstrate here that CD5 is recruited and tightly colocalized with CD3 in different human and murine IS. Following transfection in a CD5-negative T cell line of CD5 fused to the green fluorescent protein, we show that CD5 recruitment includes a fast Ag-independent and a slower Ag-dependent component. In video-imaging recordings of doubly transfected cells, the movements of CD3 and CD5 show similar kinetics, and the amount of CD3 recruited to the synapse is unaffected by CD5 expression. Moreover, APC-T cell adhesion is unchanged in CD5-expressing cells. Despite this, the extent of tyrosine phosphorylation at the synapse and the amplitude of calcium responses induced by Ag recognition are both decreased by CD5. These inhibitions increase with CD5 membrane levels. They also requires the pseudo-immunoreceptor tyrosine-based activation motif expressed in the cytoplasmic domain of the molecule. Thus, CD5 is rapidly recruited at the IS and lowers the T cell response elicited by Ag presentation by targeting downstream signaling events without affecting IS formation.
Related Concept Videos
Inhibition of Cdk Activity
The JAK-STAT Signaling Pathway
Immunoglobulin-like Cell Adhesion Molecules
Ig-CAMs exhibit either homophilic binding (to other Ig-CAMs) or heterophilic binding (to other ligands such as integrins). While most Ig-CAMs...
Inhibition of CDK Activity
T Cell Activation and Clonal Selection
Naive T cells that have not yet encountered an antigen express two primary CD...
Cytotoxic T Cells-mediated Immune Response
Immunological surveillance is the ability of immune cells to monitor and eliminate infected cells with intracellular pathogens, neoplastically transformed cells, and cells with non-self antigens. Cytotoxic T cells and NK...

