title: Is CTLA-4 a master switch for peripheral T cell tolerance?
abstract: The CD28/CTLA-4 and B7 families of cell surface molecules regulate a complex pathway of T cell signals that profoundly affect peripheral T cell responses. On the one hand, CD28/B7-mediated T cell costimulation is essential for the development and maintenance of T cell responses. In contrast, the prevailing data suggest that the engagement of CTLA-4 with the same B7 ligands down-regulates the initiation and progression of immune responses. This commentary examines the role of CTLA-4-mediated signaling in the regulation of the immune response, leading to the hypothesis that the CTLA-4/B7 interaction plays an essential role in the establishment of peripheral self-tolerance as well as the regulation of normal T cell immunity.
authors.affiliation: Ben May Institute for Cancer Research, Committee on Immunology, University of Chicago, IL 60615, USA. jbluest@immunology.uchicago.edu
authors.forename: J A
authors.initials: JA
authors.lastname: Bluestone
mesh_terms: D000069594:Abatacept; D000818:Animals; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000502:physiology*; D060908:CTLA-4 Antigen; D007108:Immune Tolerance; D018796:Immunoconjugates; D008213:Lymphocyte Activation; D015398:Signal Transduction / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D060908:CTLA-4 Antigen; D018796:Immunoconjugates; D000069594:Abatacept