Abstract
Mechanical forces acting on ligand-engaged T-cell receptors (TCRs) have previously been implicated in T-cell antigen recognition, yet their magnitude, spread, and temporal behavior are still poorly defined. We here report a FRET-based sensor equipped either with a TCR-reactive single chain antibody fragment or peptide-loaded MHC, the physiological TCR-ligand. The sensor was tethered to planar glass-supported lipid bilayers (SLBs) and informed most directly on the magnitude and kinetics of TCR-imposed forces at the single molecule level. When confronting T-cells with gel-phase SLBs we observed both prior and upon T-cell activation a single, well-resolvable force-peak of approximately 5 pN and force loading rates on the TCR of 1.5 pN per second. When facing fluid-phase SLBs instead, T-cells still exerted tensile forces yet of threefold reduced magnitude and only prior to but not upon activation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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CD4-Positive T-Lymphocytes / chemistry
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CD4-Positive T-Lymphocytes / immunology
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CD8-Positive T-Lymphocytes / chemistry
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CD8-Positive T-Lymphocytes / immunology
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Cytochromes c / chemistry
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Fluorescence Resonance Energy Transfer / instrumentation
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Fluorescence Resonance Energy Transfer / methods*
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Histocompatibility Antigens / chemistry*
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Histocompatibility Antigens / immunology
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Kinetics
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Ligands
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Lipid Bilayers / chemistry
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Mice
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Peptides / chemistry
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Receptors, Antigen, T-Cell / chemistry*
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Receptors, Antigen, T-Cell / immunology
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Single Molecule Imaging / instrumentation
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Single Molecule Imaging / methods*
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Single-Chain Antibodies / chemistry*
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Single-Chain Antibodies / immunology
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Spatio-Temporal Analysis
Substances
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Histocompatibility Antigens
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Ligands
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Lipid Bilayers
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Peptides
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Receptors, Antigen, T-Cell
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Single-Chain Antibodies
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Cytochromes c