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Temporal analysis of T-cell receptor-imposed forces via quantitative single molecule FRET measurements.

Janett GöhringFlorian KellnerLukas SchranglRené PlatzerEnrico KlotzschHannes StockingerJohannes B HuppaGerhard J Schütz
Published in: Nature communications (2021)
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.
Keyphrases
  • single molecule
  • regulatory t cells
  • living cells
  • atomic force microscopy
  • drug delivery
  • dendritic cells
  • high resolution
  • immune response
  • cancer therapy
  • mass spectrometry
  • binding protein