title: B-cell activation by helper T-cell membranes.
abstract: Resting B cells can be stimulated to proliferate and differentiate to antibody-producing cells by the combination of cell contact and soluble signals provided by activated primed helper T (Th) cells. The ability of purified plasma membranes from activated Th cell clones and recombinant lymphokines to reconstitute B cell proliferation and differentiation has allowed an increased understanding of B cell activation and characterization of the molecules involved. B cell-Th cell contact appears sufficient for delivering the proliferative signal to B cells in the absence of lymphokines. A receptor ligand pair that plays a critical role in delivery of the contact signal is CD40 on the B cell surface and the ligand for CD40 on activated Th cells. Lymphokines alone do not drive resting B cell differentiation, however, when these soluble signals are delivered during the time of B cell DNA replication, they effect B cell differentiation and isotype switching. Delivery of the CD40-dependent contact signal to resting B cells appears to require a high degree of CD40 crosslinking on the B cell surface. Providing contact signals to naive B cells with recombinant molecules in membrane fractions may allow the generation of methodology to support the production of novel antibodies in vitro.
authors.affiliation: Department of Inflammatory Diseases, Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT 06877, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Kehry
authors.forename: P D
authors.initials: PD
authors.lastname: Hodgkin
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000276:immunology; D000944:Antigens, Differentiation, B-Lymphocyte / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D019013:CD40 Antigens; D002454:Cell Differentiation; D002462:Cell Membrane / Q000276:immunology; D004261:DNA Replication; D006801:Humans; D008024:Ligands; D008213:Lymphocyte Activation / Q000276:immunology*; D008222:Lymphokines / Q000276:immunology; D015398:Signal Transduction; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; D019013:CD40 Antigens; D008024:Ligands; D008222:Lymphokines