title: Co-stimulation of antigen-specific CD4 T cells by 4-1BB ligand.
abstract: 4-1BB is a member of the TNF receptor family predominantly expressed on activated T cells, and binds an inducible ligand found on B cells, macrophages and dendritic cells. Whereas ligation of 4-1BB has been shown to enhance response of purified CD8 T cells to mitogens, and to augment NK activity and generation of cytotoxic T lymphocytes in vivo, there are little direct data on 4-1BB action during CD4 responses. Using pigeon cytochrome c-presenting fibroblast antigen-presenting cells transfected with 4-1BB ligand (4-1BBL), we show that engaging 4-1BB on naive CD4 cells promotes proliferation, cell cycle progression and IL-2 secretion, and suppresses cell death, all to a similar extent as B7-1 engagement of CD28. In addition, 4-1BBL synergizes with B7 and ICAM to enhance naive CD4 proliferation when antigen is limiting. 4-1BBL alone, and to a greater extent with B7, also augmented IL-2 secretion resting antigen-experienced CD4 cells, as typified by T helper clones, whereas short-term effector cells showed similar levels of proliferation and cytokine secretion regardless of whether 4-1BB was engaged. A major role in augmenting IFN-gamma, IL-4 or IL-5 was not demonstrated. Blocking studies with activated B cells presenting antigen showed that 4-1BB participates in promoting IL-2 production by resting CD4 cells, confirming that 4-1BBL can play a role in antigen-specific CD4 T cell responses.
authors.affiliation: La Jolla Institute for Allergy and Immunology, Division of Immunochemistry, San Diego 92121, USA.
authors.forename: I
authors.initials: I
authors.lastname: Gramaglia
authors.forename: D
authors.initials: D
authors.lastname: Cooper
authors.forename: K T
authors.initials: KT
authors.lastname: Miner
authors.forename: B S
authors.initials: BS
authors.lastname: Kwon
authors.forename: M
authors.initials: M
authors.lastname: Croft
mesh_terms: D053330:4-1BB Ligand; D000818:Animals; D017951:Antigen Presentation; D002478:Cells, Cultured; D008024:Ligands; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008822:Mice, Transgenic; D013601:T-Lymphocytes / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology*
chemical_list: D053330:4-1BB Ligand; D008024:Ligands; C505975:Tnfsf9 protein, mouse; D014409:Tumor Necrosis Factor-alpha