title: Antigen-driven T cell expansion: affinity rules.
abstract: TCR affinity and ligand off-rate have both been found to influence the degree of T cell activation by peptide-MHC. A report in this issue of Immunity finds that ligand off-rate does not correlate with antigen-specific peripheral T cell expansion. Moreover, the data point to the surprising notion that there exist TCR affinity thresholds and, once attained, T cells with higher affinity receptors have no competitive advantage.
authors.affiliation: Laboratory of Immune Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Ashwell
mesh_terms: D000818:Animals; D045304:Cytochromes c / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000378:metabolism*; D051379:Mice; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D006377:T-Lymphocytes, Helper-Inducer / Q000502:physiology*
chemical_list: D000949:Histocompatibility Antigens Class II; D011948:Receptors, Antigen, T-Cell; D045304:Cytochromes c