title: Immune regulation by CD40 and its ligand GP39.
abstract: Over the past three years, CD40 and its ligand (gp39, CD40L, TBAM) have been shown to be essential for humoral immune responses to thymus-dependent antigens. However, as the tissue distribution widens for those cells that express CD40 and gp39, we can now show that this ligand-receptor pair also plays an important role in the selection of self-reactive T cells in the thymus (central tolerance) and the regulation of tolerance in mature T cells (peripheral tolerance). Advances in our understanding of the molecular basis for CD40 biology is based in two areas of research. First, a major breakthrough in our understanding of how CD40 transduces biological events centers on the identification of a novel protein that binds to the cytoplasmic tail of CD40 and may act as a signal transducing molecule. Secondly, advances in molecular modeling and mutagenesis of this ligand-receptor pair have helped to identify the critical receptor/ligand contacts in the gp39/CD40 complex. Advances in each of these areas are discussed.
authors.affiliation: Department of Microbiology, Dartmouth Medical School, Lebanon, New Hampshire 03756, USA.
authors.forename: T M
authors.initials: TM
authors.lastname: Foy
authors.forename: A
authors.initials: A
authors.lastname: Aruffo
authors.forename: J
authors.initials: J
authors.lastname: Bajorath
authors.forename: J E
authors.initials: JE
authors.lastname: Buhlmann
authors.forename: R J
authors.initials: RJ
authors.lastname: Noelle
mesh_terms: D000818:Animals; D019013:CD40 Antigens / Q000737:chemistry / Q000276:immunology* / Q000502:physiology*; D023201:CD40 Ligand; D006801:Humans; D008024:Ligands; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000276:immunology* / Q000502:physiology*; D015398:Signal Transduction / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D019013:CD40 Antigens; D008024:Ligands; D008562:Membrane Glycoproteins; D023201:CD40 Ligand