Force-Regulated In Situ TCR-Peptide-Bound MHC Class II Kinetics Determine Functions of CD4+ T Cells

J Immunol. 2015 Oct 15;195(8):3557-64. doi: 10.4049/jimmunol.1501407. Epub 2015 Sep 2.


We have recently shown that two-dimensional (2D) and force-regulated kinetics of TCR-peptide-bound MHC class I (pMHC-I) interactions predict responses of CD8(+) T cells. To test whether these findings are applicable to CD4(+) T cells, we analyzed the in situ 3.L2 TCR-pMHC-II interactions for a well-characterized panel of altered peptide ligands on the T cell surface using the adhesion frequency assay with a micropipette and the thermal fluctuation and force-clamp assays with a biomembrane force probe. We found that the 2D effective TCR-pMHC-II affinity and off-rate correlate with, but better predict the T cell response than, the corresponding measurements with the surface plasmon resonance in three dimensions. The 2D affinity of the CD4 for MHC-II was very low, approaching the detection limit, making it one to two orders of magnitude lower than the affinity of CD8 for MHC-I. In addition, the signal-dependent cooperation between TCR and coreceptor for pMHC binding previously observed for CD8 was not observed for CD4. Interestingly, force elicited TCR-pMHC-II catch-slip bonds for agonists but slip-only bonds for antagonists, thereby amplifying the power of discrimination between altered peptide ligands. These results show that the force-regulated 2D binding kinetics of the 3.L2 TCR for pMHC-II determine functions of CD4(+) T cells.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • CD4-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / immunology
  • Histocompatibility Antigens Class I / genetics
  • Histocompatibility Antigens Class I / immunology
  • Histocompatibility Antigens Class II / genetics
  • Histocompatibility Antigens Class II / immunology*
  • Mice
  • Mice, Transgenic
  • Peptides / immunology*
  • Receptors, Antigen, T-Cell / genetics
  • Receptors, Antigen, T-Cell / immunology*


  • Histocompatibility Antigens Class I
  • Histocompatibility Antigens Class II
  • Peptides
  • Receptors, Antigen, T-Cell