Our current mixed chimerism has reliably achieved long-term kidney graft survival exclusively in monkeys (60%) displaying low memory T cell reactivity against their donors prior to transplantation in cynomolgus monkeys (5-7). The presence of regulatory T cells (Tregs) capable of suppressing anti-donor inflammatory responses in vitro was consistently detected in tolerant animals. On the other hand, monkeys displaying high anti-donor memory responsiveness rejected kidney allografts in an acute fashion (6,7). Finally, it is important to note that approximately half of the long-term surviving kidney allografts succumb eventually to chronic rejection (8). These observations stress the need to improve our protocol in order to achieve tolerance to kidney and islet/kidney transplants in 100% of monkeys. Projects 1 and 2 of this program project propose a series of novel strategies designed to induce tolerance to kidney and islet/kidney allografts in monkeys. Successful tolerance induction in both of these studies rely on the basic principles that prevention/suppression of pro-inflammatory alloimmunity combined with enhancement of immune regulation will promote tolerogenesis. Proiect 3 is 1) to investigate the mechanisms by which the in vivo treatments described in Projects 1 and 2 influence the immune response in monkeys transplanted with allogeneic kidneys, islets or islet/kidneys and, 2) elucidate the nature of the cells, soluble factors and immunological mechanisms involved in induction and maintenance of transplant tolerance. This knowledge will help us determine how to select the appropriate donor/recipient combinations and to refine the treatments proposed in Project 1 and 2 in order to reliably achieve tolerance to kidney and islet transplants in primates. To study this, we propose the following Aims:
Specific aim 1. Investigate donor hematopoietic mixed chimerism, leukocyte recovery and deleterious alloimmune T cell responses in transplanted monkeys Specific aim 2. Investigate regulatory T cell responses associated with transplant tolerance Specific aim 3. Investigate B cell responses and their contribution to rejection and tolerance Understanding the mechanisms by which tolerance is induced and maintained in our primate transplant model should significantly expand the successful application of tolerance protocols in clinical transplantation and for the treatment of immune-mediated diseases requiring tolerogenesis of harmful memory T cells in patients such as autoimmune disorders and allergies.
Project 3 will elucidate the nature of the cells, soluble factors and immunological mechanisms involved in induction and maintenance of tolerance (indefinite survival of transplants without immunosuppression) to kidney and pancreatic islets in non-human primates. Understanding the mechanisms by which tolerance is induced and maintained in our primate transplant model should significantly expand the successful application of tolerance protocols in clinical transplantation and for the treatment of immune-mediated diseases requiring tolerogenesis of harmful memory T cells in patients such as autoimmune disorders and allergies.
|Dehnadi, Abbas; Benedict Cosimi, A; Neal Smith, Rex et al. (2017) Prophylactic orthosteric inhibition of leukocyte integrin CD11b/CD18 prevents long-term fibrotic kidney failure in cynomolgus monkeys. Nat Commun 8:13899|
|Pathiraja, V; Villani, V; Tasaki, M et al. (2017) Tolerance of Vascularized Islet-Kidney Transplants in Rhesus Monkeys. Am J Transplant 17:91-102|
|Hotta, Kiyohiko; Aoyama, Akihiro; Oura, Tetsu et al. (2016) Induced regulatory T cells in allograft tolerance via transient mixed chimerism. JCI Insight 1:|
|Oura, Tetsu; Ko, Dicken S C; Boskovic, Svjetlan et al. (2016) Kidney Versus Islet Allograft Survival After Induction of Mixed Chimerism With Combined Donor Bone Marrow Transplantation. Cell Transplant 25:1331-41|
|Granados, Jose M M; Benichou, Gilles; Kawai, Tatsuo (2015) Hematopoietic stem cell infusion/transplantation for induction of allograft tolerance. Curr Opin Organ Transplant 20:49-56|
|Tonsho, M; Lee, S; Aoyama, A et al. (2015) Tolerance of Lung Allografts Achieved in Nonhuman Primates via Mixed Hematopoietic Chimerism. Am J Transplant 15:2231-9|
|Yamada, Y; Nadazdin, O; Boskovic, S et al. (2015) Repeated Injections of IL-2 Break Renal Allograft Tolerance Induced via Mixed Hematopoietic Chimerism in Monkeys. Am J Transplant 15:3055-66|
|Oura, Tetsu; Hotta, Kiyohiko; Cosimi, A B et al. (2015) Transient mixed chimerism for allograft tolerance. Chimerism 6:21-6|
|Kant, Cavit D; Akiyama, Yoshinobu; Tanaka, Katsunori et al. (2015) Both rejection and tolerance of allografts can occur in the absence of secondary lymphoid tissues. J Immunol 194:1364-71|
|Wang, Ping; Schuetz, Christian; Vallabhajosyula, Prashanth et al. (2015) Monitoring of Allogeneic Islet Grafts in Nonhuman Primates Using MRI. Transplantation 99:1574-81|
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