Induction of specific immunologic tolerance is an ultimate goal of organ transplantation. Based on the conditioning regimen developed in our laboratory by decades-long research in nonhuman primates (NHP), we have now successfully achieved renal allograft tolerance in HLA mismatched human kidney transplant recipients via the mixed chimerism approach. However, limitations of this approach have been its inapplicability for deceased donor transplantation and the inability to induce tolerance of non-renal organs/cells. To extend this approach to deceased donor transplantation, we recently developed a novel strategy of "delayed tolerance" induction, where kidney transplantation is performed first with conventional immunosuppression, followed by conditioning and donor bone marrow transplantation at a later date. In our preliminary NHP investigations, several barriers to consistent tolerance induction with this novel approach have been identified including higher alloreactive memory T cells (Tmem) and inflammatory responses. In order to develop a consistently reliable conditioning regimen for clinical application to deceased donor kidney recipients, it is essential to identify additional modalities to effectively mitigate inflammatory and Tmem responses without increasing morbidity in the recipients.
Aims 1 and 2 of this project are, therefore, designed to evaluate novel anti-inflammatory agents (anti-IL6R mAb and alpha1 antitrypsin) and strategies to overcome Tmem responses (costimulatory blockade and B cell depletion). This Project's goals also include extension of the applicability of our approach to organ/cell transplantation other than the kidney. This appears to be possible via the novel strategy of co-transplantation of the kidney with less tolerogenic organs/cells. Our studies have shown that the kidney allograft plays a critical role for induction and maintenance of tolerance of the co-transplanted organ/cells.
Aim 3 of the current study is thus designed to induce islet allograft tolerance by co-transplantation of islets and the kidney. While Project 2 will pursue islets allograft tolerance in living donor transplantation. Project 1 will develop the strategy to induce islet allograft tolerance in deceased donor transplantation. Since islets are especially susceptible to inflammatory and Tmem responses, we will incorporate novel modalities to be identified in Aims 1 and 2 into the conditioning regimen for induction of islet allograft tolerance. Finally, mechanisms by which (transient) mixed chimerism and the renal allograft induce islet allograft tolerance, will be fully investigated in collaboration with Project 3.

Public Health Relevance

Successful induction of allograft tolerance has been achieved in HLA mismatched human kidney transplant recipients via mixed chimerism. This research proposal is directed to identify novel modalities to extend our mixed chimerism approach to a much wider population of human allograft recipients and to islet allograft tolerance. Our NHP model has been proven highly relevant to clinical organ transplantation and observations from these studies should be directly transferrable to clinical application.

National Institute of Health (NIH)
Research Program--Cooperative Agreements (U19)
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Special Emphasis Panel (ZAI1)
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Massachusetts General Hospital
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Oura, T; Hotta, K; Lei, J et al. (2016) Immunosuppression With CD40 Costimulatory Blockade Plus Rapamycin for Simultaneous Islet-Kidney Transplantation in Nonhuman Primates. Am J Transplant :
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
Hotta, Kiyohiko; Aoyama, Akihiro; Oura, Tetsu et al. (2016) Induced regulatory T cells in allograft tolerance via transient mixed chimerism. JCI Insight 1:
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
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
Oura, Tetsu; Hotta, Kiyohiko; Cosimi, A B et al. (2015) Transient mixed chimerism for allograft tolerance. Chimerism 6:21-6
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
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
Scalea, Joseph R; Villani, Vincenzo; Gillon, Bradford C et al. (2014) Development of antidonor antibody directed toward non-major histocompatibility complex antigens in tolerant animals. Transplantation 98:514-9

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