SERIAL TRIGGERING OF TCRS - A BASIS FOR THE SENSITIVITY AND SPECIFICITY OF ANTIGEN RECOGNITION

Sensitivity of antigen detection by B cells correlates with high-affin ity binding. This paradigm does nor appear to hold for the T-cell rece ptor (TCR), which is able to bind its ligand - peptide in the context of major histocompatibility complex (MHC) - with low affinity. Here, S alvatore Valitutti and Antonio Lanzavecchia propose that the efficienc y of T-cell antigen recognition is dependent upon optimal kinetics of the TCR-peptide-MHC interaction, allowing serial engagements and trigg ering of many TCRs by a few peptide-MHC complexes.