Coinhibitory T-Cell Signaling in Islet Allograft Rejection and Tolerance
Abstract:Autoaggressive T cells directed against insulin secreting pancreatic -cells mediate the development of type 1 diabetes. Islet transplantation offers superior glycemic control over exogenous insulin, but chronic immunosuppression limits its broad application. Pathogenic T cells are also important in allograft rejection. Inducing and maintaining antigen-specific peripheral T-cell tolerance toward -cells is an attractive strategy to prevent autoimmune disease, and to facilitate treatment of diabetes with islet allografts without long-term immunosuppression. Recent efforts have focused on blocking costimulatory T-cell signals for tolerance induction. Although costimulatory blockade can prolong graft survival, true immunological tolerance remains elusive. Costimulatory signals may even be required for the maintenance of peripheral tolerance. The discovery of novel coinhibitory T-cell pathways, including CTLA-4, PD-1, and BTLA, offers an alternative approach. Stimulating negative T cell cosignals alone or in combination may help induce tolerance. The focus of this review is to summarize the strategies directed at turning off the immune response by exploiting these negative cosignaling pathways in tolerance induction in islet transplantation. Activating several coinhibitory pathways together may be synergistic in preventing pathogenic T-cell responses. Tolerance induction will likely rely on understanding the balance of positive and negative signals affecting the state of T-cell activation.
Document Type: Review Article
Affiliations: 1: Department of Surgery, Faculty of Medicine, University of Alberta, Edmonton, AB, Canada 2: Department of Pathology and Laboratory Medicine, Joseph Stokes, Jr. Research Institute and Biesecker Pediatric Liver Center, Children's Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA, USA
Publication date: February 1, 2006
- Cell Transplantation publishes original, peer-reviewed research and review articles on the subject of cell transplantation and its application to human diseases. To ensure high-quality contributions from all areas of transplantation, separate section editors and editorial boards have been established. Articles deal with a wide range of topics including physiological, medical, preclinical, tissue engineering, and device-oriented aspects of transplantation of nervous system, endocrine, growth factor-secreting, bone marrow, epithelial, endothelial, and genetically engineered cells, among others. Basic clinical studies and immunological research papers are also featured. To provide complete coverage of this revolutionary field, Cell Transplantation will report on relevant technological advances, and ethical and regulatory considerations of cell transplants. Cell Transplantation is now an Open Access journal starting with volume 18 in 2009, and therefore there will be an inexpensive publication charge, which is dependent on the number of pages, in addition to the charge for color figures. This will allow work to be disseminated to a wider audience and also entitle the corresponding author to a free PDF, as well as prepublication of an unedited version of the manuscript.