A response calculus for immobilized T cell receptor ligands

J Biol Chem. 2001 Dec 28;276(52):49125-32. doi: 10.1074/jbc.M109396200. Epub 2001 Oct 9.


To address the molecular mechanism of T cell receptor (TCR) signaling, we have formulated a model for T cell activation, termed the 2D-affinity model, in which the density of TCR on the T cell surface, the density of ligand on the presenting surface, and their corresponding two-dimensional affinity determine the level of T cell activation. When fitted to T cell responses against purified ligands immobilized on plastic surfaces, the 2D-affinity model adequately simulated changes in cellular activation as a result of varying ligand affinity and ligand density. These observations further demonstrated the importance of receptor cross-linking density in determining TCR signaling. Moreover, it was found that the functional two-dimensional affinity of TCR ligands was affected by the chemical composition of the ligand-presenting surface. This makes it possible that cell-bound TCR ligands, despite their low affinity in solution, are of optimal two-dimensional affinity thereby allowing effective TCR binding under physiological conditions, i.e. at low ligand densities in cellular interfaces.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antibodies / immunology
  • Antibodies / metabolism
  • Genes, Reporter
  • Ligands
  • Lymphocyte Activation*
  • Mathematics
  • Models, Immunological*
  • Protein Binding
  • Receptors, Antigen, T-Cell / metabolism*
  • Recombinant Fusion Proteins / immunology
  • Recombinant Fusion Proteins / metabolism
  • Signal Transduction / physiology*
  • Superantigens / immunology
  • Superantigens / metabolism
  • T-Lymphocytes / immunology*


  • Antibodies
  • Ligands
  • Receptors, Antigen, T-Cell
  • Recombinant Fusion Proteins
  • Superantigens