title: 4-1 BB ligand--just another costimulating molecule?
abstract: Initially, scientific interest in the 4-1BB/4-1BB Ligand system focused on the role of the 4-1BB (CD137) receptor in the costimulation of T cells. More recently, evidence is accumulating that 4-1BBL is more than "just" the ligand for a costimulatory molecule. In this review we discuss the functional properties of 4-1BB Ligand such as its preference for CD8 positive T cells and the differences to costimulation via the B7/CD28 system. Furthermore, the available data regarding its ability to transduce signals bidirectionally, i.e. also back into the ligand bearing cell, its release as a soluble form following shedding from the cell surface, and its role in the interaction of tumor cells with the immune system are reviewed.
authors.affiliation: Department of Internal Medicine II, University Hospital of the Eberhard Karls University, Tübingen, Gernany. Helmut.Salih@med.uni-tuebingen.de
authors.forename: H R
authors.initials: HR
authors.lastname: Salih
authors.forename: P A
authors.initials: PA
authors.lastname: Kiener
authors.forename: V
authors.initials: V
authors.lastname: Nüssler
mesh_terms: D053330:4-1BB Ligand; D005786:Gene Expression Regulation; D006801:Humans; D008213:Lymphocyte Activation; D009369:Neoplasms / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D013601:T-Lymphocytes / Q000166:cytology / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism*
chemical_list: D053330:4-1BB Ligand; C505974:TNFSF9 protein, human; D014409:Tumor Necrosis Factor-alpha