Interactions of TCRs with MHC-peptide complexes: a quantitative basis for mechanistic models

The activation of T lymphocytes is initiated by the binding of MHC—peptide complexes on antigen-presenting cells to MHC-restricted, peptide specific TCRs. Significant progress has recently been made in understanding the structure of the TCR and in the direct quantitative examination of the primary binding interactions between MHC—peptide complexes and the TCR. Attempts to develop quantitative models for the differential activation of T cells by MHC—peptide ligands that differ subtly in their structure have largely been based on either the affinity of the MHC—peptide complexes for the TCR in question or on the dissociation kinetics of the MHC—peptide complex from the T cell.