title: Accessory cell-derived signals required for T cell activation.
abstract: Various populations of accessory cells differ in their abilities to function as effective antigen-presenting cells (APC) and stimulate CD4+ T cells to produce interleukin-2. Three important factors directly related to APC potency are the expression of class II major histocompatibility complex molecules and the ability to present peptide antigens to the T cell antigen receptor, the expression of costimulatory ligands which deliver important activation signals independent of T cell receptor occupancy and the expression of adhesion molecules which promote conjugate formation so that these activation signals can be effectively delivered to the T cells. The relative importance of these accessory cell functions in T cell activation will be discussed, with an emphasis on costimulation and the CD28/B7 receptor/ligand pair. The consequence of inadequate costimulation by an otherwise effective APC in inducing T cell anergy will also be discussed.
authors.affiliation: Department of Microbiology, University of Minnesota, Minneapolis 55455.
authors.forename: J G
authors.initials: JG
authors.lastname: Johnson
authors.forename: M K
authors.initials: MK
authors.lastname: Jenkins
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D000941:Antigens / Q000276:immunology / Q000378:metabolism; D015703:Antigens, CD / Q000502:physiology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000502:physiology; D018106:CD28 Antigens; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D016466:CHO Cells; D015815:Cell Adhesion Molecules / Q000502:physiology; D002460:Cell Line; D002522:Chlorocebus aethiops; D006224:Cricetinae; D016207:Cytokines / Q000502:physiology; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D006801:Humans; D007108:Immune Tolerance; D018799:Intercellular Adhesion Molecule-1; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D016169:Lymphocyte Function-Associated Antigen-1 / Q000502:physiology; D051379:Mice; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D015398:Signal Transduction
chemical_list: D000941:Antigens; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D018106:CD28 Antigens; D015815:Cell Adhesion Molecules; D016207:Cytokines; D000949:Histocompatibility Antigens Class II; D007376:Interleukin-2; D016169:Lymphocyte Function-Associated Antigen-1; D011948:Receptors, Antigen, T-Cell; D018799:Intercellular Adhesion Molecule-1