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Peterson L, Yacoub MH, Ayares D, Yamada K, Eisenson D, Griffith BP, Mohiuddin MM, Eyestone W, Venter JC, Smolenski RT, Rothblatt M. Physiological basis for xenotransplantation from genetically modified pigs to humans. Physiol Rev 2024; 104:1409-1459. [PMID: 38517040 DOI: 10.1152/physrev.00041.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 03/06/2024] [Accepted: 03/14/2024] [Indexed: 03/23/2024] Open
Abstract
The collective efforts of scientists over multiple decades have led to advancements in molecular and cellular biology-based technologies including genetic engineering and animal cloning that are now being harnessed to enhance the suitability of pig organs for xenotransplantation into humans. Using organs sourced from pigs with multiple gene deletions and human transgene insertions, investigators have overcome formidable immunological and physiological barriers in pig-to-nonhuman primate (NHP) xenotransplantation and achieved prolonged pig xenograft survival. These studies informed the design of Revivicor's (Revivicor Inc, Blacksburg, VA) genetically engineered pigs with 10 genetic modifications (10 GE) (including the inactivation of 4 endogenous porcine genes and insertion of 6 human transgenes), whose hearts and kidneys have now been studied in preclinical human xenotransplantation models with brain-dead recipients. Additionally, the first two clinical cases of pig-to-human heart xenotransplantation were recently performed with hearts from this 10 GE pig at the University of Maryland. Although this review focuses on xenotransplantation of hearts and kidneys, multiple organs, tissues, and cell types from genetically engineered pigs will provide much-needed therapeutic interventions in the future.
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Affiliation(s)
- Leigh Peterson
- United Therapeutics Corporation, Silver Spring, Maryland, United States
| | | | - David Ayares
- United Therapeutics Corporation, Silver Spring, Maryland, United States
| | - Kazuhiko Yamada
- Department of Surgery, Division of Transplantation, Johns Hopkins Medicine, Baltimore, Maryland, United States
| | - Daniel Eisenson
- Department of Surgery, Division of Transplantation, Johns Hopkins Medicine, Baltimore, Maryland, United States
| | - Bartley P Griffith
- University of Maryland Medical Center, Baltimore, Maryland, United States
| | | | - Willard Eyestone
- United Therapeutics Corporation, Silver Spring, Maryland, United States
| | - J Craig Venter
- J. Craig Venter Institute, Rockville, Maryland, United States
| | | | - Martine Rothblatt
- United Therapeutics Corporation, Silver Spring, Maryland, United States
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2
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Goldstone AB, Bacha EA, Sykes M. On cardiac xenotransplantation and the role of xenogeneic tolerance. J Thorac Cardiovasc Surg 2023; 166:968-972. [PMID: 36621453 PMCID: PMC10267285 DOI: 10.1016/j.jtcvs.2022.11.036] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/23/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022]
Affiliation(s)
- Andrew B Goldstone
- Section of Congenital and Pediatric Cardiac Surgery, Division of Cardiothoracic Surgery, Morgan Stanley Children's Hospital of New York, Columbia University, New York, NY
| | - Emile A Bacha
- Section of Congenital and Pediatric Cardiac Surgery, Division of Cardiothoracic Surgery, Morgan Stanley Children's Hospital of New York, Columbia University, New York, NY
| | - Megan Sykes
- Departments of Medicine, Microbiology and Immunology, and Surgery, Columbia Center for Translational Immunology, Department of Medicine, Columbia University, New York, NY.
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3
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Lei T, Chen L, Wang K, Du S, Gonelle-Gispert C, Wang Y, Buhler LH. Genetic engineering of pigs for xenotransplantation to overcome immune rejection and physiological incompatibilities: The first clinical steps. Front Immunol 2022; 13:1031185. [PMID: 36561750 PMCID: PMC9766364 DOI: 10.3389/fimmu.2022.1031185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022] Open
Abstract
Xenotransplantation has the potential to solve the shortfall of human organ donors. Genetically modified pigs have been considered as potential animal donors for human xenotransplantation and have been widely used in preclinical research. The genetic modifications aim to prevent the major species-specific barriers, which include humoral and cellular immune responses, and physiological incompatibilities such as complement and coagulation dysfunctions. Genetically modified pigs can be created by deleting several pig genes related to the synthesis of various pig specific antigens or by inserting human complement- and coagulation-regulatory transgenes. Finally, in order to reduce the risk of infection, genes related to porcine endogenous retroviruses can be knocked down. In this review, we focus on genetically modified pigs and comprehensively summarize the immunological mechanism of xenograft rejection and recent progress in preclinical and clinical studies. Overall, both genetically engineered pig-based xenografts and technological breakthroughs in the biomedical field provide a promising foundation for pig-to-human xenotransplantation in the future.
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Affiliation(s)
- Tiantian Lei
- Department of Pharmacy, Women and Children’s Hospital of Chongqing Medical University, Chongqing Health Center for Women and Children, Chongqing, China
| | - Lin Chen
- Department of Pharmacy, Women and Children’s Hospital of Chongqing Medical University, Chongqing Health Center for Women and Children, Chongqing, China
| | - Kejing Wang
- Department of Pharmacy, Women and Children’s Hospital of Chongqing Medical University, Chongqing Health Center for Women and Children, Chongqing, China
| | - Suya Du
- Department of Clinical Pharmacy, Sichuan Cancer Hospital and Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Sichuan, China
| | - Carmen Gonelle-Gispert
- Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland,*Correspondence: Carmen Gonelle-Gispert, ; Yi Wang, ; Leo H. Buhler,
| | - Yi Wang
- Department of Critical Care Medicine, Sichuan Academy of Medical Science and Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China,*Correspondence: Carmen Gonelle-Gispert, ; Yi Wang, ; Leo H. Buhler,
| | - Leo H. Buhler
- Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland,*Correspondence: Carmen Gonelle-Gispert, ; Yi Wang, ; Leo H. Buhler,
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4
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Eisenson DL, Hisadome Y, Santillan MR, Yamada K. Progress in islet xenotransplantation: Immunologic barriers, advances in gene editing, and tolerance induction strategies for xenogeneic islets in pig-to-primate transplantation. FRONTIERS IN TRANSPLANTATION 2022; 1:989811. [PMID: 38390384 PMCID: PMC10883655 DOI: 10.3389/frtra.2022.989811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
Islet transplantation has emerged as a curative therapy for diabetes in select patients but remains rare due to shortage of suitable donor pancreases. Islet transplantation using porcine islets has long been proposed as a solution to this organ shortage. There have already been several small clinical trials using porcine islets in humans, but results have been mixed and further trials limited by calls for more rigorous pre-clinical data. Recent progress in heart and kidney xenograft transplant, including three studies of pig-to-human xenograft transplant, have recaptured popular imagination and renewed interest in clinical islet xenotransplantation. This review outlines immunologic barriers to islet transplantation, summarizes current strategies to overcome these barriers with a particular focus on approaches to induce tolerance, and describes an innovative strategy for treatment of diabetic nephropathy with composite islet-kidney transplantation.
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Affiliation(s)
- Daniel L Eisenson
- Department of Surgery, The Johns Hopkins Hospital, Baltimore, MD, United States
| | - Yu Hisadome
- Department of Surgery, The Johns Hopkins Hospital, Baltimore, MD, United States
| | | | - Kazuhiko Yamada
- Department of Surgery, The Johns Hopkins Hospital, Baltimore, MD, United States
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5
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Sykes M, Sachs DH. Progress in xenotransplantation: overcoming immune barriers. Nat Rev Nephrol 2022; 18:745-761. [PMID: 36198911 DOI: 10.1038/s41581-022-00624-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2022] [Indexed: 11/09/2022]
Abstract
A major limitation of organ allotransplantation is the insufficient supply of donor organs. Consequently, thousands of patients die every year while waiting for a transplant. Progress in xenotransplantation that has permitted pig organ graft survivals of years in non-human primates has led to renewed excitement about the potential of this approach to alleviate the organ shortage. In 2022, the first pig-to-human heart transplant was performed on a compassionate use basis, and xenotransplantation experiments using pig kidneys in deceased human recipients provided encouraging data. Many advances in xenotransplantation have resulted from improvements in the ability to genetically modify pigs using CRISPR-Cas9 and other methodologies. Gene editing has the capacity to generate pig organs that more closely resemble those of humans and are hence more physiologically compatible and less prone to rejection. Despite such modifications, immune responses to xenografts remain powerful and multi-faceted, involving innate immune components that do not attack allografts. Thus, the induction of innate and adaptive immune tolerance to prevent rejection while preserving the capacity of the immune system to protect the recipient and the graft from infection is desirable to enable clinical xenotransplantation.
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Affiliation(s)
- Megan Sykes
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University, New York, NY, USA. .,Department of Surgery, Columbia University, New York, NY, USA. .,Department of Microbiology and Immunology, Columbia University, New York, NY, USA.
| | - David H Sachs
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University, New York, NY, USA. .,Department of Surgery, Columbia University, New York, NY, USA.
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6
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Eisenson DL, Hisadome Y, Yamada K. Progress in Xenotransplantation: Immunologic Barriers, Advances in Gene Editing, and Successful Tolerance Induction Strategies in Pig-To-Primate Transplantation. Front Immunol 2022; 13:899657. [PMID: 35663933 PMCID: PMC9157571 DOI: 10.3389/fimmu.2022.899657] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 04/20/2022] [Indexed: 02/05/2023] Open
Abstract
Organ transplantation is the most effective treatment for end stage organ failure, but there are not enough organs to meet burgeoning demand. One potential solution to this organ shortage is xenotransplantation using pig tissues. Decades of progress in xenotransplantation, accelerated by the development of rapid genome editing tools, particularly the advent of CRISPR-Cas9 gene editing technologies, have enabled remarkable advances in kidney and heart xenotransplantation in pig-to-nonhuman primates. These breakthroughs in large animal preclinical models laid the foundation for three recent pig-to-human transplants by three different groups: two kidney xenografts in brain dead recipients deemed ineligible for transplant, and one heart xenograft in the first clinical grade study of pig-to-human transplantation. However, despite tremendous progress, recent data including the first clinical case suggest that gene-modification alone will not overcome all xenogeneic immunologic barriers, and thus an active and innovative immunologic strategy is required for successful xenotransplantation. This review highlights xenogeneic immunologic barriers, advances in gene editing, and tolerance-inducing strategies in pig-to-human xenotransplantation.
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Affiliation(s)
- Daniel L Eisenson
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, United States.,Department of Surgery, The Johns Hopkins Hospital, Baltimore, MD, United States
| | - Yu Hisadome
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, United States
| | - Kazuhiko Yamada
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, United States.,Department of Surgery, Columbia University Irving Medical Center, New York, NY, United States
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7
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Takeuchi K, Ariyoshi Y, Shimizu A, Okumura Y, Cara-Fuentes G, Garcia GE, Pomposelli T, Watanabe H, Boyd L, Ekanayake-Alper DK, Amarnath D, Sykes M, Sachs DH, Johnson RJ, Yamada K. Expression of human CD47 in pig glomeruli prevents proteinuria and prolongs graft survival following pig-to-baboon xenotransplantation. Xenotransplantation 2021; 28:e12708. [PMID: 34418164 DOI: 10.1111/xen.12708] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 07/29/2021] [Accepted: 08/01/2021] [Indexed: 12/19/2022]
Abstract
BACKGROUND Nephrotic syndrome is a common complication of pig-to-baboon kidney xenotransplantation (KXTx) that adversely affects outcomes. We have reported that upregulation of CD80 and down-regulation of SMPDL-3b in glomeruli have an important role in the development of proteinuria following pig-to-baboon KXTx. Recently we found induced expression of human CD47 (hCD47) on endothelial cells and podocytes isolated from hCD47 transgenic (Tg) swine markedly reduced phagocytosis by baboon and human macrophages. These observations led us to hypothesize that transplanting hCD47 Tg porcine kidneys could overcome the incompatibility of the porcine CD47-baboon SIRPα interspecies ligand-receptor interaction and prevent the development of proteinuria following KXTx. METHODS Ten baboons received pig kidneys with vascularized thymic grafts (n = 8) or intra-bone bone marrow transplants (n = 2). Baboons were divided into three groups (A, B, and C) based on the transgenic expression of hCD47 in GalT-KO pigs. Baboons in Group A received kidney grafts with expression of hCD47 restricted to glomerular cells (n = 2). Baboons in Group B received kidney grafts with high expression of hCD47 on both glomerular and tubular cells of the kidneys (n = 4). Baboons in Group C received kidney grafts with low/no glomerular expression of hCD47, and high expression of hCD47 on renal tubular cells (n = 4). RESULTS Consistent with this hypothesis, GalT-KO/hCD47 kidney grafts with high expression of hCD47 on glomerular cells developed minimal proteinuria. However, high hCD47 expression in all renal cells including renal tubular cells induced an apparent destructive inflammatory response associated with upregulated thrombospondin-1. This response could be avoided by a short course of weekly anti-IL6R antibody administration, resulting in prolonged survival without proteinuria (mean 170.5 days from 47.8 days). CONCLUSION Data showed that transgenic expression of hCD47 on glomerular cells in the GalT-KO donor kidneys can prevent xenograft nephropathy, a significant barrier for therapeutic applications of xenotransplantation. The ability to prevent nephrotic syndrome following KXTx overcomes a critical barrier for future clinical applications of KXTx.
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Affiliation(s)
- Kazuhiro Takeuchi
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University, New York, New York, USA
| | - Yuichi Ariyoshi
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University, New York, New York, USA
| | - Akira Shimizu
- Department of Analytic Human Pathology, Nippon Medical School, Tokyo, Japan
| | - Yuichiro Okumura
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University, New York, New York, USA
| | - Gabriel Cara-Fuentes
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, Colorado, USA
| | - Gabriela E Garcia
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, Colorado, USA
| | - Thomas Pomposelli
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University, New York, New York, USA
| | - Hironosuke Watanabe
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University, New York, New York, USA
| | - Lennan Boyd
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University, New York, New York, USA
| | - Dilrukshi K Ekanayake-Alper
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University, New York, New York, USA
| | - Dasari Amarnath
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University, New York, New York, USA
| | - Megan Sykes
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University, New York, New York, USA.,Department of Surgery, Columbia University Medical Center, New York, New York, USA
| | - David H Sachs
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University, New York, New York, USA.,Department of Surgery, Columbia University Medical Center, New York, New York, USA
| | - Richard J Johnson
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, Colorado, USA
| | - Kazuhiko Yamada
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University, New York, New York, USA.,Department of Surgery, Columbia University Medical Center, New York, New York, USA
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8
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Extensive germline genome engineering in pigs. Nat Biomed Eng 2020; 5:134-143. [PMID: 32958897 DOI: 10.1038/s41551-020-00613-9] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 08/22/2020] [Indexed: 12/30/2022]
Abstract
The clinical applicability of porcine xenotransplantation-a long-investigated alternative to the scarce availability of human organs for patients with organ failure-is limited by molecular incompatibilities between the immune systems of pigs and humans as well as by the risk of transmitting porcine endogenous retroviruses (PERVs). We recently showed the production of pigs with genomically inactivated PERVs. Here, using a combination of CRISPR-Cas9 and transposon technologies, we show that pigs with all PERVs inactivated can also be genetically engineered to eliminate three xenoantigens and to express nine human transgenes that enhance the pigs' immunological compatibility and blood-coagulation compatibility with humans. The engineered pigs exhibit normal physiology, fertility and germline transmission of the 13 genes and 42 alleles edited. Using in vitro assays, we show that cells from the engineered pigs are resistant to human humoral rejection, cell-mediated damage and pathogenesis associated with dysregulated coagulation. The extensive genome engineering of pigs for greater compatibility with the human immune system may eventually enable safe and effective porcine xenotransplantation.
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9
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Sykes M, Sachs DH. Transplanting organs from pigs to humans. Sci Immunol 2020; 4:4/41/eaau6298. [PMID: 31676497 DOI: 10.1126/sciimmunol.aau6298] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 10/02/2019] [Indexed: 12/20/2022]
Abstract
The success of organ transplantation is limited by the complications of immunosuppression, by chronic rejection, and by the insufficient organ supply, and thousands of patients die every year while waiting for a transplant. With recent progress in xenotransplantation permitting porcine organ graft survival of months or even years in nonhuman primates, there is renewed interest in its potential to alleviate the organ shortage. Many of these advances are the result of our heightened capacity to modify pigs genetically, particularly with the development of CRISPR-Cas9-based gene editing methodologies. Although this approach allows the engineering of pig organs that are less prone to rejection, the clinical application of xenotransplantation will require the ability to avoid the ravages of a multifaceted attack on the immune system while preserving the capacity to protect both the recipient and the graft from infectious microorganisms. In this review, we will discuss the potential and limitations of these modifications and how the engineering of the graft can be leveraged to alter the host immune response so that all types of immune attack are avoided.
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Affiliation(s)
- Megan Sykes
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University Medical Center, NY, USA. .,Department of Microbiology and Immunology, Columbia University Medical Center, NY, USA.,Department of Surgery, Columbia University Medical Center, NY, USA
| | - David H Sachs
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University Medical Center, NY, USA.,Department of Surgery, Columbia University Medical Center, NY, USA
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10
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Zeng S, Xiao Z, Wang Q, Guo Y, He Y, Zhu Q, Zou Y. Strategies to achieve immune tolerance in allogeneic solid organ transplantation. Transpl Immunol 2020; 58:101250. [DOI: 10.1016/j.trim.2019.101250] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 10/19/2019] [Accepted: 10/21/2019] [Indexed: 12/14/2022]
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11
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Thomas A, Hawthorne WJ, Burlak C. Xenotransplantation literature update, November/December 2019. Xenotransplantation 2020; 27:e12582. [PMID: 31984549 DOI: 10.1111/xen.12582] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Accepted: 01/14/2020] [Indexed: 12/13/2022]
Abstract
The ever-increasing disparity between the lack of organ donors and patients on the transplant waiting list is increasing worldwide. For the past several decades xenotransplantation has led the way to correct this deficit and remains clearly the only feasible option to provide a means to meet the demand for patients in need of an organ transplant. Xenotransplantation's ability to provide a specifically designed unlimited supply of organs, suited to treat the various needs for transplant organs and cells, has recently been championed by successful pre-clinical trials that have run long-term in non-human primate studies. In this review we show how these improvements have come about due to long-term dedicated research and recent advances in biomedical engineering technology, such as genome editing tools including zinc finger nucleases, TALEN, and CRISPER/Cas9 which have paved the way for significant breakthroughs in improving xenograft outcomes through genetic modifications to the donor source pig. Other novel approaches include the development of decellularized porcine tissue, such as corneas which can now be transplanted into patients with the minimal need for immunosuppression or other side effects. Further genetic variants of the porcine genome are also now being optimized to abrogate rejection. The emergence of new modalities such as; mesenchymal stem cells, donor thymic vascularization, in vivo bioreactors, chemokine and cytokine therapies have come to show improvements in xenograft outcomes. Furthermore, new studies confirm the safety status of using porcine xenografts, verifying that with current technologies and approaches, the issue of PERV transmission is a moot point. These breakthroughs and technological advancements push the reality of xenotransplantation one step closer to the clinic.
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Affiliation(s)
- Adwin Thomas
- The Centre for Transplant & Renal Research, The Westmead Institute for Medical Research, Westmead, NSW, Australia
| | - Wayne J Hawthorne
- The Centre for Transplant & Renal Research, The Westmead Institute for Medical Research, Westmead, NSW, Australia.,The Department of Surgery, University of Sydney, Westmead Hospital, Westmead, NSW, Australia
| | - Christopher Burlak
- Department of Surgery, Schulze Diabetes Institute, University of Minnesota Medical School, Minneapolis, Minnesota
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12
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Yamada K, Ariyoshi Y, Pomposelli T, Sekijima M. Co-transplantation of Vascularized Thymic Graft with Kidney in Pig-to-Nonhuman Primates for the Induction of Tolerance Across Xenogeneic Barriers. Methods Mol Biol 2020; 2110:151-171. [PMID: 32002908 DOI: 10.1007/978-1-0716-0255-3_11] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Using advanced gene editing technologies, xenotransplantation from multi-transgenic alpha-1,3-galactosyltransferase knockout pigs has demonstrated marked prolongation of renal xenograft survival, ranging from days to greater than several months for life-supporting kidneys and >2 years in a heterotopic non-life-supporting cardiac xenograft model. However, continuous administration of multiple immunosuppressive drugs continues to be required, and attempts to taper immunosuppression have been unsuccessful. These data are consistent with previous reports indicating that the human-anti-porcine T cell response is similar or stronger than that across allogeneic barriers. Due to the strength of both the innate and adaptive immune responses in xenotransplantation, the level of continuous immunosuppression needed to control these responses and prolong xenograft survival has been associated with prohibitive morbidity and mortality. These facts provide compelling rationale to pursue a clinically applicable strategy for the induction of tolerance.Mixed chimerism and thymic tissue transplantation have both achieved xenogeneic tolerance in pig-to-mouse models, and both have recently been extended to pig-to-baboon models. Although these strategies are promising in small animal models, neither direct intravenous injection of porcine bone marrow cells nor direct fetal thymic tissue transplantation into recipients was able to achieve >2 days chimerism following BM Tx or the engraftment of thymic tissues across xenogeneic barriers in pig-to-nonhuman primate models. Several innovative procedures have been largely developed by Kazuhiko Yamada to overcome these failures. These include vascularized thymic transplantation, combined with either thymokidney (TK) or vascularized thymic lobe (VTL) transplantation. Utilizing the strategy of transplanting vascularized thymic grafts with kidney from the same GalT-KO donor without further gene modification, we have achieved longer than 6 months survival of life-supporting kidneys in a baboon. Notably, the recipient became donor specific unresponsive and developed new thymic emigrants. In this chapter, we introduce a brief summary of our achievements to date toward the successful induction of tolerance by utilizing our novel strategy of vascularized thymic transplantation (including thymokidney transplantation), as well as describe the step-by-step methodology of surgical and in vitro procedures which are required for this experiment.
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Affiliation(s)
- Kazuhiko Yamada
- Yamada Laboratory, Department of Surgery, Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY, USA.
| | - Yuichi Ariyoshi
- Yamada Laboratory, Department of Surgery, Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY, USA
| | - Thomas Pomposelli
- Yamada Laboratory, Department of Surgery, Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY, USA
| | - Mitsuhiro Sekijima
- Yamada Laboratory, Department of Surgery, Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY, USA
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13
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Intra-bone Bone Marrow Transplantation in Pig-to-Nonhuman Primates for the Induction of Tolerance Across Xenogeneic Barriers. Methods Mol Biol 2020; 2110:213-225. [PMID: 32002911 DOI: 10.1007/978-1-0716-0255-3_14] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mixed chimerism and thymic tissue transplantation strategies have achieved xenogeneic tolerance in pig-to-mouse models, and both have been extended to pig-to-baboon models. A mixed chimerism strategy has shown promise toward inducing tolerance in allogeneic models in mice, pigs, nonhuman primates (NHP), humans, and a rat-to-mouse small animal xeno-model. However, even though α-1,3-galactosyltransferase gene knockout (GalTKO) pigs have been used as bone marrow (BM) donors, direct intravenous injection of porcine BM cells was detected for only up to 4 days (peripheral macro-chimerism) in one case, and the rest lost chimerism within 2 days.Recent data in allogeneic models demonstrated that direct injection of donor BM cells into recipient BM spaces (intra-bone bone marrow transplantation: IBBMTx) produces rapid reconstitution and a higher survival rate compared to i.v. injection. In order to minimize the loss of injected porcine BM peripherally before reaching the BM space, Yamada developed a xeno-specific regimen including IBBMTx coated with a collagen gel matrix in a preclinical pig-to-baboon model (Yamada IBBMTx). This strategy aims to achieve improved, persistent macro-chimerism as well as engraftment of BM across a xenogeneic barrier. The initial study published in 2015 demonstrated that this IBBMTx strategy leads to markedly prolonged peripheral macro-chimerism detectable for up to 23 days. Furthermore, a more recent study using human CD47-transgenic (Tg) GalTKO pigs as xeno-donors achieved long-lasting macro-chimerism >60 days with evidence of reduction of anti-pig natural antibodies (nAb). This is the longest macro-chimerism that has ever been achieved in a preclinical large animal xenotransplant model to date. In this chapter, we introduce a brief summary of our achievements in regard to successful tolerance induction by utilizing our novel strategy of IBBMTx as well as describe the step-by-step methodology of surgical and in vitro procedures that are required for this project.
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14
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Nauman G, Borsotti C, Danzl N, Khosravi-Maharlooei M, Li HW, Chavez E, Stone S, Sykes M. Reduced positive selection of a human TCR in a swine thymus using a humanized mouse model for xenotolerance induction. Xenotransplantation 2020; 27:e12558. [PMID: 31565822 PMCID: PMC7007369 DOI: 10.1111/xen.12558] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 08/27/2019] [Accepted: 09/13/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND Tolerance-inducing approaches to xenotransplantation would be optimal and may be necessary for long-term survival of transplanted pig organs in human patients. The ideal approach would generate donor-specific unresponsiveness to the pig organ without suppressing the patient's normal immune function. Porcine thymus transplantation has shown efficacy in promoting xenotolerance in humanized mice and large animal models. However, murine studies demonstrate that T cells selected in a swine thymus are positively selected only by swine thymic epithelial cells, and therefore, cells expressing human HLA-restricted TCRs may not be selected efficiently in a transplanted pig thymus. This may lead to suboptimal patient immune function. METHODS To assess human thymocyte selection in a pig thymus, we used a TCR transgenic humanized mouse model to study positive selection of cells expressing the MART1 TCR, a well-characterized human HLA-A2-restricted TCR, in a grafted pig thymus. RESULTS Positive selection of T cells expressing the MART1 TCR was inefficient in both a non-selecting human HLA-A2- or swine thymus compared with an HLA-A2+ thymus. Additionally, CD8 MART1 TCRbright T cells were detected in the spleens of mice transplanted with HLA-A2+ thymi but were significantly reduced in the spleens of mice transplanted with swine or HLA-A2- thymi. [Correction added on October 15, 2019, after first online publication: The missing superscript values +, -, and bright have been included in the Results section.] CONCLUSIONS: Positive selection of cells expressing a human-restricted TCR in a transplanted pig thymus is inefficient, suggesting that modifications to improve positive selection of cells expressing human-restricted TCRs in a pig thymus may be necessary to support development of a protective human T-cell pool in future patients.
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Affiliation(s)
- Grace Nauman
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University Medical Center, Columbia University, New York, NY, USA
- Department of Microbiology and Immunology, Columbia University Medical Center, Columbia University, New York, NY, USA
| | - Chiara Borsotti
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University Medical Center, Columbia University, New York, NY, USA
| | - Nichole Danzl
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University Medical Center, Columbia University, New York, NY, USA
| | - Mohsen Khosravi-Maharlooei
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University Medical Center, Columbia University, New York, NY, USA
| | - Hao-Wei Li
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University Medical Center, Columbia University, New York, NY, USA
| | - Estefania Chavez
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University Medical Center, Columbia University, New York, NY, USA
| | - Samantha Stone
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University Medical Center, Columbia University, New York, NY, USA
| | - Megan Sykes
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University Medical Center, Columbia University, New York, NY, USA
- Department of Microbiology and Immunology, Columbia University Medical Center, Columbia University, New York, NY, USA
- Department of Surgery, Columbia University Medical Center, Columbia University, New York, NY, USA
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15
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Xenotransplantation tolerance: applications for recent advances in modified swine. Curr Opin Organ Transplant 2019; 23:642-648. [PMID: 30379724 DOI: 10.1097/mot.0000000000000585] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW The aim of this study was to review the recent progress in xenotransplantation achieved through genetic engineering and discuss the potential of tolerance induction to overcome remaining barriers to extended xenograft survival. RECENT FINDINGS The success of life-saving allotransplantation has created a demand for organ transplantation that cannot be met by the supply of human organs. Xenotransplantation is one possible solution that would allow for a nearly unlimited supply of organs. Recent genetic engineering of swine has decreased the reactivity of preformed antibodies to some, but not all, potential human recipients. Experiments using genetically modified swine organs have now resulted in survival of life-supporting kidneys for over a year. However, the grafts show evidence of antibody-mediated rejection on histology, suggesting additional measures will be required for further extension of graft survival. Tolerance induction through mixed chimerism or thymic transplantation across xenogeneic barriers would be well suited for patients with a positive crossmatch to genetically modified swine or relatively negative crossmatches to genetically modified swine, respectively. SUMMARY This review highlights the current understanding of the immunologic processes in xenotransplantation and describes the development and application of strategies designed to overcome them from the genetic modification of the source animal to the induction of tolerance to xenografts.
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Sekijima M, Sahara H, Shimizu A, Iwanaga T, Murokawa T, Ariyoshi Y, Pomposelli T, Khosravi Maharlooei M, Sykes M, Yamada K. Preparation of hybrid porcine thymus containing non-human primate thymic epithelial cells in miniature swine. Xenotransplantation 2019; 26:e12543. [PMID: 31293016 DOI: 10.1111/xen.12543] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 05/26/2019] [Accepted: 06/04/2019] [Indexed: 01/17/2023]
Abstract
BACKGROUND We have achieved greater than a 6-month survival of a life-supporting kidney co-transplanted with a vascularized thymic graft into non-human primates (NHPs). Although we have achieved pig-specific unresponsiveness in vitro, immunosuppression was not able to be fully weaned. Studies in mice and humanized mice suggest that a hybrid pig thymus (Hyb-thy)-containing host thymic epithelial cells (TECs) can optimize intra-thymic selection, achieving xenograft tolerance with improved reconstitution of T-cell function. METHODS We have tested the feasibility of the preparation of a Hyb-thy that contains NHP TECs in the donor thymic grafts. We first prepared the Hyb-thy in the donor pigs 2-3 weeks before xeno-Tx. We performed six cases of Hyb-thy preparation in six juvenile miniature swine. Two pigs received non-manipulated cynomolgus monkey thymic cells that were isolated from an excised atrophic thymus via injection into their thymic lobes (Group 1). The remaining four received thymic cells that were isolated from non-atrophic thymic glands (Groups 2 and 3). Pigs in Group 2 received unmanipulated thymic cells in one thymic lobe, as well as CD2-positive cell-depleted TEC-enriched cells in the contralateral lobe. Pigs in Group 3 received TEC-enriched cells alone. RESULTS All thymus-injected pigs received tacrolimus and rapamycin until endpoint (POD16). We detected cynomolgus monkey TEC networks in pig thymus from Groups 1 and 3, while pigs in Group 2 rejected the thymic cells. We demonstrated the preparation of Hyb-thy in pigs using tacrolimus plus rapamycin therapy. CONCLUSIONS Our results suggest that the enrichment of TEC from the excised NHP thymus facilitated NHP TEC engraftment in pig thymus.
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Affiliation(s)
- Mitsuhiro Sekijima
- Division of Organ Replacement and Xenotransplantation Surgery, Center for Advanced Biomedical Science and Swine Research, Kagoshima University, Kagoshima, Japan
| | - Hisashi Sahara
- Division of Organ Replacement and Xenotransplantation Surgery, Center for Advanced Biomedical Science and Swine Research, Kagoshima University, Kagoshima, Japan.,Department of Surgery, Columbia University Center for Translational Immunology, Columbia University, New York, New York
| | - Akira Shimizu
- Department of Analytic Human Pathology, Nippon Medical School, Tokyo, Japan
| | - Takehiro Iwanaga
- Division of Organ Replacement and Xenotransplantation Surgery, Center for Advanced Biomedical Science and Swine Research, Kagoshima University, Kagoshima, Japan
| | - Takahiro Murokawa
- Division of Organ Replacement and Xenotransplantation Surgery, Center for Advanced Biomedical Science and Swine Research, Kagoshima University, Kagoshima, Japan
| | - Yuichi Ariyoshi
- Division of Organ Replacement and Xenotransplantation Surgery, Center for Advanced Biomedical Science and Swine Research, Kagoshima University, Kagoshima, Japan
| | - Thomas Pomposelli
- Department of Surgery, Columbia University Center for Translational Immunology, Columbia University, New York, New York
| | - Mohsen Khosravi Maharlooei
- Department of Surgery, Columbia University Center for Translational Immunology, Columbia University, New York, New York
| | - Megan Sykes
- Department of Surgery, Columbia University Center for Translational Immunology, Columbia University, New York, New York
| | - Kazuhiko Yamada
- Department of Surgery, Columbia University Center for Translational Immunology, Columbia University, New York, New York
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Sykes M. IXA Honorary Member Lecture, 2017: The long and winding road to tolerance. Xenotransplantation 2018; 25:e12419. [PMID: 29913040 DOI: 10.1111/xen.12419] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 05/03/2018] [Indexed: 12/18/2022]
Abstract
The last 15 years or so have seen exciting progress in xenotransplantation, with porcine organ grafts surviving months or even years in non-human primates. These advances reflect the application of new scientific knowledge, improved immunosuppressive agents, and genetic engineering. The field has recently enjoyed a renaissance of interest and hope, largely due to the exponential increase in our capacity to genetically engineer porcine source animals. However, immune responses to xenografts are very powerful and widespread clinical application of xenotransplantation will depend on the ability to suppress these immune responses while preserving the capacity to protect both the recipient and the graft from infectious microorganisms. Our work over the last three decades has aimed to engineer the immune system of the recipient in a manner that achieves specific tolerance to the xenogeneic donor while preserving otherwise normal immune function. Important proofs of principle have been obtained, first in rodents, and later in human immune systems in "humanized mice" and finally in non-human primates, demonstrating the capacity and potential synergy of mixed xenogeneic chimerism and xenogeneic thymic transplantation in tolerizing multiple arms of the immune system. Considering the fact that clinical tolerance has recently been achieved for allografts and the even greater importance of avoiding excessive immunosuppression for xenografts, it is my belief that it is both possible and imperative that we likewise achieve xenograft tolerance. I expect this to be accomplished through the availability of targeted approaches to recipient immune conditioning, understanding of immunological mechanisms of tolerance, advanced knowledge of physiological incompatibilities, and the availability of inbred miniature swine with optimized use of genetic engineering.
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Affiliation(s)
- Megan Sykes
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY, USA.,Department of Medicine, Columbia University, New York, NY, USA.,Department of Microbiology & Immunology, Columbia University, New York, NY, USA.,Department of Surgery, Columbia University, New York, NY, USA
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18
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Watanabe H, Sahara H, Nomura S, Tanabe T, Ekanayake-Alper DK, Boyd LK, Louras NJ, Asfour A, Danton MA, Ho SH, Arn JS, Hawley RJ, Shimizu A, Nagayasu T, Ayares D, Lorber MI, Sykes M, Sachs DH, Yamada K. GalT-KO pig lungs are highly susceptible to acute vascular rejection in baboons, which may be mitigated by transgenic expression of hCD47 on porcine blood vessels. Xenotransplantation 2018; 25:e12391. [PMID: 29527745 PMCID: PMC6135720 DOI: 10.1111/xen.12391] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 01/12/2018] [Accepted: 02/08/2018] [Indexed: 12/20/2022]
Abstract
BACKGROUND Despite recent progress in survival times of xenografts in non-human primates, there are no reports of survival beyond 5 days of histologically well-aerated porcine lung grafts in baboons. Here, we report our initial results of pig-to-baboon xeno-lung transplantation (XLTx). METHODS Eleven baboons received genetically modified porcine left lungs from either GalT-KO alone (n = 3), GalT-KO/humanCD47(hCD47)/hCD55 (n = 3), GalT-KO/hD47/hCD46 (n = 4), or GalT-KO/hCD39/hCD46/hCD55/TBM/EPCR (n = 1) swine. The first 2 XLTx procedures were performed under a non-survival protocol that allowed a 72-hour follow-up of the recipients with general anesthesia, while the remaining 9 underwent a survival protocol with the intention of weaning from ventilation. RESULTS Lung graft survivals in the 2 non-survival animals were 48 and >72 hours, while survivals in the other 9 were 25 and 28 hours, at 5, 5, 6, 7, >7, 9, and 10 days. One baboon with graft survival >7 days, whose entire lung graft remained well aerated, was euthanized on POD 7 due to malfunction of femoral catheters. hCD47 expression of donor lungs was detected in both alveoli and vessels only in the 3 grafts surviving >7, 9, and 10 days. All other grafts lacked hCD47 expression in endothelial cells and were completely rejected with diffuse hemorrhagic changes and antibody/complement deposition detected in association with early graft loss. CONCLUSIONS To our knowledge, this is the first evidence of histologically viable porcine lung grafts beyond 7 days in baboons. Our results indicate that GalT-KO pig lungs are highly susceptible to acute humoral rejection and that this may be mitigated by transgenic expression of hCD47.
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Affiliation(s)
- Hironosuke Watanabe
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY
| | - Hisashi Sahara
- Division of Organ Replacement and Xenotransplantation Surgery, Center for Advanced Biomedical Science and Swine Research, Kagoshima University, Kagoshima, Japan
| | - Shunichiro Nomura
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY
| | - Tatsu Tanabe
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY
| | | | - Lennan K. Boyd
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY
| | - Nathan J. Louras
- Transplantation Biology Research Laboratories, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Arsenoi Asfour
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY
| | - Makenzie A. Danton
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY
| | - Siu-Hong Ho
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY
| | - J. Scott Arn
- Transplantation Biology Research Laboratories, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Robert J. Hawley
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY
| | - Akira Shimizu
- Department of Analytic Human Pathology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Takeshi Nagayasu
- Department of Surgical Oncology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | | | | | - Megan Sykes
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY
| | - David H. Sachs
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY
- Transplantation Biology Research Laboratories, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Kazuhiko Yamada
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY
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19
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Ezekian B, Schroder PM, Freischlag K, Yoon J, Kwun J, Knechtle SJ. Contemporary Strategies and Barriers to Transplantation Tolerance. Transplantation 2018; 102:1213-1222. [PMID: 29757903 PMCID: PMC6059978 DOI: 10.1097/tp.0000000000002242] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 12/30/2022]
Abstract
The purpose of this review is to discuss immunologic tolerance as it applies to solid organ transplantation and to identify barriers that hinder the achievement of this long-term goal. First, the definition of tolerance and an introduction of mechanisms by which tolerance exists or can be achieved will be discussed. Next, a review of contemporary attempts at achieving transplant tolerance will be described. Finally, a discussion of the humoral barriers to transplantation tolerance and potential ways to overcome these barriers will be presented.
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Affiliation(s)
- Brian Ezekian
- Duke Transplant Center, Department of Surgery, Duke University Medical Center, Durham, NC
| | - Paul M. Schroder
- Duke Transplant Center, Department of Surgery, Duke University Medical Center, Durham, NC
| | - Kyle Freischlag
- Duke Transplant Center, Department of Surgery, Duke University Medical Center, Durham, NC
| | - Janghoon Yoon
- Duke Transplant Center, Department of Surgery, Duke University Medical Center, Durham, NC
| | - Jean Kwun
- Duke Transplant Center, Department of Surgery, Duke University Medical Center, Durham, NC
| | - Stuart J. Knechtle
- Duke Transplant Center, Department of Surgery, Duke University Medical Center, Durham, NC
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20
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Liu L, He C, Liu J, Lv Z, Wang G, Gao H, Dai Y, Cooper DKC, Cai Z, Mou L. Transplant Tolerance: Current Insights and Strategies for Long-Term Survival of Xenografts. Arch Immunol Ther Exp (Warsz) 2018; 66:355-364. [PMID: 29992337 DOI: 10.1007/s00005-018-0517-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 06/18/2018] [Indexed: 12/20/2022]
Abstract
Xenotransplantation is an attractive solution to the problem of allograft shortage. However, transplants across discordant species barriers are subject to vigorous immunologic and pathobiologic hurdles, some of which might be overcome with the induction of immunologic tolerance. Several strategies have been designed to induce tolerance to a xenograft at both the central (including induction of mixed chimerism and thymic transplantation) and peripheral (including adoptive transfer of regulatory cells and blocking T cell costimulation) levels. Currently, xenograft tolerance has been well-established in rodent models, but these protocols have not yet achieved similar success in nonhuman primates. This review will discuss the major barriers that impede the establishment of immunological tolerance across xenogeneic barriers and the potential solution to these challenges, and provide a perspective on the future of the development of novel tolerance-inducing strategies.
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Affiliation(s)
- Lu Liu
- Shenzhen Xenotransplantation Medical Engineering Research and Development Center' Institute of Translational Medicine, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen University School of Medicine, Shenzhen University Health Science Center, Shenzhen, 518035, Guangdong, China.,Department of Gastroenterology' Center For Digestive Diseases, People's Hospital of Baoan District, The 8th people's Hospital of Shenzhen, Shenzhen, 518101, Guangdong, China
| | - Chen He
- Department of Ophthalmology, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen, 518035, Guangdong, China
| | - Jintao Liu
- Department of Gastroenterology' Center For Digestive Diseases, People's Hospital of Baoan District, The 8th people's Hospital of Shenzhen, Shenzhen, 518101, Guangdong, China
| | - Zhiwu Lv
- Department of Gastroenterology' Center For Digestive Diseases, People's Hospital of Baoan District, The 8th people's Hospital of Shenzhen, Shenzhen, 518101, Guangdong, China
| | - Ganlu Wang
- Department of Gastroenterology' Center For Digestive Diseases, People's Hospital of Baoan District, The 8th people's Hospital of Shenzhen, Shenzhen, 518101, Guangdong, China
| | - Hanchao Gao
- Shenzhen Xenotransplantation Medical Engineering Research and Development Center' Institute of Translational Medicine, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen University School of Medicine, Shenzhen University Health Science Center, Shenzhen, 518035, Guangdong, China
| | - Yifan Dai
- Jiangsu Key Laboratory of Xenotransplantation, Nanjing Medical University, Nanjing, 210029, Jiangsu, China
| | - David K C Cooper
- Xenotransplantation Program/Department of Surgery, The University of Alabama at Birmingham, Birmingham, AL, 35233, USA
| | - Zhiming Cai
- Shenzhen Xenotransplantation Medical Engineering Research and Development Center' Institute of Translational Medicine, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen University School of Medicine, Shenzhen University Health Science Center, Shenzhen, 518035, Guangdong, China
| | - Lisha Mou
- Shenzhen Xenotransplantation Medical Engineering Research and Development Center' Institute of Translational Medicine, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen University School of Medicine, Shenzhen University Health Science Center, Shenzhen, 518035, Guangdong, China.
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21
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Zuber J, Sykes M. Mechanisms of Mixed Chimerism-Based Transplant Tolerance. Trends Immunol 2017; 38:829-843. [PMID: 28826941 PMCID: PMC5669809 DOI: 10.1016/j.it.2017.07.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 06/24/2017] [Accepted: 07/19/2017] [Indexed: 02/06/2023]
Abstract
Immune responses to allografts represent a major barrier in organ transplantation. Immune tolerance to avoid chronic immunosuppression is a critical goal in the field, recently achieved in the clinic by combining bone marrow transplantation (BMT) with kidney transplantation following non-myeloablative conditioning. At high levels of chimerism such protocols can permit central deletional tolerance, but with a significant risk of graft-versus-host (GVH) disease (GVHD). By contrast, transient chimerism-based tolerance is devoid of GVHD risk and appears to initially depend on regulatory T cells (Tregs) followed by gradual, presumably peripheral, clonal deletion of donor-reactive T cells. Here we review recent mechanistic insights into tolerance and the development of more robust and safer protocols for tolerance induction that will be guided by innovative immune monitoring tools.
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Affiliation(s)
- Julien Zuber
- Service de Transplantation Rénale, Hôpital Necker, Université Paris Descartes, Paris, France; INSERM UMRS_1163, IHU Imagine, Paris, France.
| | - Megan Sykes
- Columbia Center for Translational Immunology, Department of Medicine, Columbia University, New York, NY 10032, USA; Department of Surgery, Columbia University, New York, NY 10032, USA; Department of Microbiology and Immunology, Columbia University Center, New York, NY 10032, USA.
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22
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Prolonged Survival of Pig Skin on Baboons After Administration of Pig Cells Expressing Human CD47. Transplantation 2017; 101:316-321. [PMID: 27232934 DOI: 10.1097/tp.0000000000001267] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Successful xenotransplantation will likely depend, in part, on the induction of immunological tolerance, because the high levels of immunosuppression otherwise required would likely have unacceptable side effects. Rapid clearance of administered porcine hematopoietic stem cells by primate macrophages has hampered previous attempts to induce tolerance through mixed hematopoietic chimerism across a pig-to-primate barrier. Phagocytosis is normally inhibited by binding of cell surface protein CD47 to macrophage signal regulatory protein α receptors. However, pig CD47 has previously been shown to be ineffective in transducing signals through primate signal regulatory protein α. METHODS Mobilized peripheral blood hematopoietic cells from transgenic swine expressing high or low levels of human CD47 were infused into conditioned baboons at 3 time points over a 9-week period. Xenogeneic peripheral blood chimerism was assessed after each infusion. Split thickness skin grafts from the hematopoietic cell donor swine were placed on recipients 5 weeks after the last cell infusion and 7 weeks after the discontinuation of all immunosuppression to test immune response. RESULTS The level and duration of transient chimerism were substantially greater in baboons receiving hematopoietic cells from a pig expressing high levels of human CD47. Skin graft survival on high CD47 recipients was prolonged as well, in 1 case showing no signs of rejection at least 53 days after placement. CONCLUSIONS Prolongation of transient porcine chimerism via transgenic expression of human CD47 in a primate model is associated with an immune modulating effect, leading to markedly prolonged survival of donor swine skin xenografts that may be applicable to clinical solid organ xenotransplantation.
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Yamada K, Shah JA, Tanabe T, Lanaspa MA, Johnson RJ. Xenotransplantation: Where Are We with Potential Kidney Recipients? Recent Progress and Potential Future Clinical Trials. CURRENT TRANSPLANTATION REPORTS 2017; 4:101-109. [PMID: 28989853 DOI: 10.1007/s40472-017-0149-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
PURPOSE Inter-species transplantation, xenotransplantation, is becoming a realistic strategy to solve the organ shortage crisis. Here we focus on seminal publications that have driven research in xenotransplantation, as well as recently published literature and future endeavors. RECENT FINDINGS Advances in gene editing technology have allowed for the efficient production of multi-transgenic porcine donors leading improved xenograft survival in baboons, up to 2-years following heterotopic heart xenotransplantation and from weeks to several months following life-supporting kidney xenotransplanation. As technology evolves, additional challenges have arisen, including the development of proteinuria, early graft loss associated with porcine CMV, disparities in organ growth between donors and recipients as well as high-dose continuous immunosuppression requirements. To address these issues, our laboratory developed a tolerance-inducing protocol which has allowed for >6 months survival of a life-supporting kidney with further approaches currently underway to address the challenges mentioned above. SUMMARY Our recent findings, reviewed in this article, led us to develop methods to overcome obstacles, which, in conjunction with the work of others, are promising for future clinical applications of xenotransplantation.
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Affiliation(s)
- Kazuhiko Yamada
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY
| | - Jigesh A Shah
- Transplantation Biology Research Laboratories, Massachusetts general Hospital, Harvard Medical School, Boston, MA
| | - Tatsu Tanabe
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY
| | - Miguel A Lanaspa
- Division of Renal Diseases and Hypertension, University of Colorado, Aurora CO
| | - Richard J Johnson
- Division of Renal Diseases and Hypertension, University of Colorado, Aurora CO
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Pan H, Gazarian A, Dubernard JM, Belot A, Michallet MC, Michallet M. Transplant Tolerance Induction in Newborn Infants: Mechanisms, Advantages, and Potential Strategies. Front Immunol 2016; 7:116. [PMID: 27092138 PMCID: PMC4823304 DOI: 10.3389/fimmu.2016.00116] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 03/14/2016] [Indexed: 12/26/2022] Open
Abstract
Although several tolerance induction protocols have been successfully implemented in adult renal transplantation, no tolerance induction approach has, as yet, been defined for solid organ transplantations in young infants. Pediatric transplant recipients have a pressing demand for the elaboration of tolerance induction regimens. Indeed, since they display a longer survival time, they are exposed to a higher level of risks linked to long-term immunosuppression (IS) and to chronic rejection. Interestingly, central tolerance induction may be of great interest in newborns, because of their immunological immaturity and the important role of the thymus at this early stage in life. The present review aims to clarify mechanisms and strategies of tolerance induction in these immunologically premature recipients. We first introduce the discovery and mechanisms of neonatal tolerance in murine experimental models and subsequently analyze tolerance induction in human newborn infants. Hematopoietic mixed chimerism in neonates is also discussed based on in utero hematopoietic stem cell (HSC) transplant studies. Then, we review the recent advances in tolerance induction approaches in adults, including the infusion of HSCs associated with less toxic conditioning regimens, regulatory T cells/facilitating cells/mesenchymal stem cells transplantation, costimulatory blockade, and thymus manipulation. Finally, IS withdrawal in pediatric solid organ transplant is discussed. In conclusion, the establishment of transplant tolerance induction in infants is promising and deserves further investigations. Future studies could focus on the selection of patients, on less toxic conditioning regimens, and on biomarkers for IS minimization or withdrawal.
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Affiliation(s)
- Hua Pan
- Chair of Transplantation, VetAgro Sup-Campus Vétérinaire de Lyon, Marcy l'Etoile, France; Plastic and Reconstructive Surgery Department, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Aram Gazarian
- Chair of Transplantation, VetAgro Sup-Campus Vétérinaire de Lyon, Marcy l'Etoile, France; Department of Hand Surgery, Clinique du Parc, Lyon, France
| | - Jean-Michel Dubernard
- Chair of Transplantation, VetAgro Sup-Campus Vétérinaire de Lyon, Marcy l'Etoile, France; Department of Transplantation, Hôpital Edouard Herriot, Lyon, France
| | - Alexandre Belot
- International Center for Infectiology Research (CIRI), Université de Lyon , Lyon , France
| | - Marie-Cécile Michallet
- Chair of Transplantation, VetAgro Sup-Campus Vétérinaire de Lyon, Marcy l'Etoile, France; Cancer Research Center Lyon (CRCL), UMR INSERM 1052 CNRS 5286, Centre Leon Berard, Lyon, France
| | - Mauricette Michallet
- Chair of Transplantation, VetAgro Sup-Campus Vétérinaire de Lyon, Marcy l'Etoile, France; Department of Hematology, Centre Hospitalier Lyon-Sud, Pierre Benite, France
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Progress towards inducing tolerance of pig-to-primate xenografts. Int J Surg 2015; 23:291-295. [PMID: 26296932 DOI: 10.1016/j.ijsu.2015.07.720] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 07/16/2015] [Accepted: 07/22/2015] [Indexed: 10/23/2022]
Abstract
Xenotransplantation remains the best near-term solution to the shortage of transplantable organs that currently limits the field of transplantation. However, because the immune response to xenografts is considerably stronger than it is to allografts, the amount of non-specific immunosuppression required to avoid xenograft rejection may limit clinical applicability. For this reason, we consider it likely that the success of clinical xenotransplantation will depend on finding ways of safely inducing tolerance across xenogeneic barriers rather than relying entirely on non-specific immunosuppressive agents. In this laboratory, two approaches are being studied for the induction of pig-to-primate tolerance: a) the simultaneous transplantation of vascularized thymus and solid organs; and b) mixed hematopoietic chimerism. A summary of the development of these two approaches and their current status is the subject of this review.
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Griesemer A, Yamada K, Sykes M. Xenotransplantation: immunological hurdles and progress toward tolerance. Immunol Rev 2015; 258:241-58. [PMID: 24517437 DOI: 10.1111/imr.12152] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The discrepancy between organ need and organ availability represents one of the major limitations in the field of transplantation. One possible solution to this problem is xenotransplantation. Research in this field has identified several obstacles that have so far prevented the successful development of clinical xenotransplantation protocols. The main immunologic barriers include strong T-cell and B-cell responses to solid organ and cellular xenografts. In addition, components of the innate immune system can mediate xenograft rejection. Here, we review these immunologic and physiologic barriers and describe some of the strategies that we and others have developed to overcome them. We also describe the development of two strategies to induce tolerance across the xenogeneic barrier, namely thymus transplantation and mixed chimerism, from their inception in rodent models through their current progress in preclinical large animal models. We believe that the addition of further beneficial transgenes to Gal knockout swine, combined with new therapies such as Treg administration, will allow for successful clinical application of xenotransplantation.
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Affiliation(s)
- Adam Griesemer
- Columbia Center for Translational Immunology, Columbia University College of Physicians and Surgeons, New York, NY, USA
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Tena A, Kurtz J, Leonard DA, Dobrinsky JR, Terlouw SL, Mtango N, Verstegen J, Germana S, Mallard C, Arn JS, Sachs DH, Hawley RJ. Transgenic expression of human CD47 markedly increases engraftment in a murine model of pig-to-human hematopoietic cell transplantation. Am J Transplant 2014; 14:2713-22. [PMID: 25278264 PMCID: PMC4236244 DOI: 10.1111/ajt.12918] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/16/2014] [Accepted: 07/06/2014] [Indexed: 01/25/2023]
Abstract
Mixed chimerism approaches for induction of tolerance of solid organ transplants have been applied successfully in animal models and in the clinic. However, in xenogeneic models (pig-to-primate), host macrophages participate in the rapid clearance of porcine hematopoietic progenitor cells, hindering the ability to achieve mixed chimerism. CD47 is a cell-surface molecule that interacts in a species-specific manner with SIRPα receptors on macrophages to inhibit phagocytosis and expression of human CD47 (hCD47) on porcine cells has been shown to inhibit phagocytosis by primate macrophages. We report here the generation of hCD47 transgenic GalT-KO miniature swine that express hCD47 in all blood cell lineages. The effect of hCD47 expression on xenogeneic hematopoietic engraftment was tested in an in vivo mouse model of human hematopoietic cell engraftment. High-level porcine chimerism was observed in the bone marrow of hCD47 progenitor cell recipients and smaller but readily measurable chimerism levels were observed in the peripheral blood of these recipients. In contrast, transplantation of WT progenitor cells resulted in little or no bone marrow engraftment and no detectable peripheral chimerism. These results demonstrate a substantial protective effect of hCD47 expression on engraftment and persistence of porcine cells in this model, presumably by modulation of macrophage phagocytosis.
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Affiliation(s)
- Aseda Tena
- Transplantation Biology Research Center, Massachusetts General Hospital, Boston, MA
| | - Josef Kurtz
- Transplantation Biology Research Center, Massachusetts General Hospital, Boston, MA,Department of Biology, Emmanuel College, Boston, MA
| | - David A. Leonard
- Transplantation Biology Research Center, Massachusetts General Hospital, Boston, MA
| | | | | | | | | | - Sharon Germana
- Transplantation Biology Research Center, Massachusetts General Hospital, Boston, MA
| | - Christopher Mallard
- Transplantation Biology Research Center, Massachusetts General Hospital, Boston, MA
| | - J. Scott Arn
- Transplantation Biology Research Center, Massachusetts General Hospital, Boston, MA
| | - David H. Sachs
- Transplantation Biology Research Center, Massachusetts General Hospital, Boston, MA
| | - Robert J. Hawley
- Transplantation Biology Research Center, Massachusetts General Hospital, Boston, MA
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Vadori M, Cozzi E. Immunological challenges and therapies in xenotransplantation. Cold Spring Harb Perspect Med 2014; 4:a015578. [PMID: 24616201 DOI: 10.1101/cshperspect.a015578] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Xenotransplantation, or the transplantation of cells, tissues, or organs between different species, was proposed a long time ago as a possible solution to the worldwide shortage of human organs and tissues for transplantation. In this setting, the pig is currently seen as the most likely candidate species. In the last decade, progress in this field has been remarkable and includes a better insight into the immunological mechanisms underlying the rejection process. Several immunological hurdles nonetheless remain, such as the strong antibody-mediated and innate or adaptive cellular immune responses linked to coagulation derangements, precluding indefinite xenograft survival. This article reviews our current understanding of the immunological mechanisms involved in xenograft rejection and the potential strategies that may enable xenotransplantation to become a clinical reality in the not-too-distant future.
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Affiliation(s)
- Marta Vadori
- CORIT (Consortium for Research in Organ Transplantation), Legnaro, 35020 Padua, Italy
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Kalscheuer H, Onoe T, Dahmani A, Li HW, Hölzl M, Yamada K, Sykes M. Xenograft tolerance and immune function of human T cells developing in pig thymus xenografts. THE JOURNAL OF IMMUNOLOGY 2014; 192:3442-50. [PMID: 24591363 DOI: 10.4049/jimmunol.1302886] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Transplantation of xenogeneic thymus tissue allows xenograft tolerance induction in the highly disparate pig-to-mouse model. Fetal swine thymus (SW THY) can support the generation of a diverse human T cell repertoire that is tolerant of the pig in vitro. We demonstrate that SW THY generates all human T cell subsets, including regulatory T cells (Tregs), in similar numbers as fetal human thymus (HU THY) grafts in immunodeficient mice receiving the same human CD34(+) cells. Peripheral T cells are specifically tolerant to the mouse and to the human and porcine donors, with robust responses to nondonor human and pig Ags. Specific tolerance is observed to pig skin grafts sharing the THY donor MHC. SW THY-generated peripheral Tregs show similar function, but include lower percentages of naive-type Tregs compared with HU THY-generated Tregs. Tregs contribute to donor-pig specific tolerance. Peripheral human T cells generated in SW THY exhibit reduced proportions of CD8(+) T cells and reduced lymphopenia-driven proliferation and memory-type conversion, accelerated decay of memory-type cells, and reduced responses to protein Ags. Thus, SW thymus transplantation is a powerful xenotolerance approach for human T cells. However, immune function may be further enhanced by strategies to permit positive selection by autologous HLA molecules.
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Affiliation(s)
- Hannes Kalscheuer
- Transplantation Biology Research Center, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114
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Scalea J, Hanecamp I, Robson SC, Yamada K. T-cell-mediated immunological barriers to xenotransplantation. Xenotransplantation 2012; 19:23-30. [PMID: 22360750 DOI: 10.1111/j.1399-3089.2011.00687.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Xenotransplantion remains the most viable option for significant expansion of the donor organ pool in clinical transplantation. With the advent of nuclear transfer technologies, the production of transgenic swine has become a possibility. These animals have allowed transplant investigators to overcome humoral mechanisms of hyperacute xenograft rejection in experimental pig-to-non-human primate models. However, other immunologic barriers preclude long-term acceptance of xenografts. This review article focuses on a major feature of xenogeneic rejection: xenogeneic T cell responses. Evidence obtained from both small and large animal models, particularly those using either islet cells or kidneys, have demonstrated that T cell responses play a major role in xenogeneic rejection, and that immunosuppression alone is likely incapable of completely suppressing these responses. Additionally, both the direct and indirect pathway of antigen presentation appear to be involved in these anti donor processes. Enhanced understanding of (i) CD47 and its role in transduced xeno-bone marrow (ii) CD39 and its role in coagulation dysregulation and (iii) thymic transplantation have provided us with encouraging results. Presently, experiments evaluating the possibility of xenogeneic tolerance are underway.
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Affiliation(s)
- Joseph Scalea
- Transplantation Biology Research Center, Massachusetts General Hospital, Boston, MA 02129, USA
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Abstract
PURPOSE OF REVIEW The present review updates the current status of research regarding the immunologic responses of the recipient following xenotransplantation. Additionally, we present the recent progress with attempts to induce xenogeneic tolerance induction. RECENT FINDINGS There continues to be great interest in xenotransplantation. Recently, descriptions of the mechanisms responsible for attempted T-cell xenogeneic tolerance in both large and small animal models have improved xenogeneic graft survivals. Additionally, the cellular signaling mechanisms, such as those involving CD39, CD44, and CD47, are proving to be highly important. Using the mixed chimerism approach to tolerance in xenogeneic model may be encouraging, especially given the recent clarification of the role for macrophage-induced phagocytosis of xenogeneic donor cells. SUMMARY Induction of tolerance to xenogeneic antigens has been accomplished only in small animals; however, graft survivals in large animal models continue to improve. Further clarification of both the adaptive and innate immune responses to xenogeneic antigens is required for success to continue.
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Affiliation(s)
- Kazuhiko Yamada
- Transplantation Biology Research Center, Massachusetts General Hospital, Boston, Massachusetts 02129, USA.
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Thymic transplantation in pig-to-nonhuman primates for the induction of tolerance across xenogeneic barriers. Methods Mol Biol 2012; 885:191-212. [PMID: 22565997 DOI: 10.1007/978-1-61779-845-0_12] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
With the advent of knockout pigs for α1,3-galactosyltransferease (GalT-KO, which lack a cell-surface antigen to which humans have preformed antibodies), investigators have extended the survival of life-supporting xenorenal grafts. However, despite these increases, nonhuman primates transplanted with GalT-KO renal grafts are susceptible to anti-donor T-cell responses that are strong or stronger than allogeneic responses. In order to prevent rejection, recipients must be subjected to morbidly high levels of immunosuppression. For these reasons, our laboratory has attempted to develop novel methods of xenogeneic tolerance using vascularized porcine thymic grafts in order to reteach the recipient's immune system to accept the xenogeneic organ as self. These strategies, largely developed by Dr. Kazuhiko Yamada, involve the co-transplantation of a vascularized donor thymus with a kidney. This has been successfully done in two ways. The first method involves the preparation of a composite tissue "thymokidney" and the second utilizes the transplantation of an isolated vascularized thymic lobe. Both strategies involve the transplantation of fully vascularized thymic tissue at the time of xenotransplantation, a fact which is crucial for function of the thymic tissue immediately after xenografting and reeducation of recipient T-cells. These strategies have successfully induced tolerance across fully allogeneic models in miniature swine and prolonged graft survival in our pig-to-baboon model of life-supporting xenotransplantation to greater than 80 days with in vitro evidence of donor-specific unresponsiveness. Although it is too early for the development of clinical renal xenotransplantation protocols, this chapter describes the authors' unique experience with one of the most promising preclinical large-animal models of xenotransplantation. Furthermore, understanding the importance and measurement of T-cell responses in xenotransplantation is contingent upon a functional knowledge of these procedures.
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Burrell BE, Ding Y, Nakayama Y, Park KS, Xu J, Yin N, Bromberg JS. Tolerance and lymphoid organ structure and function. Front Immunol 2011; 2:64. [PMID: 22566853 PMCID: PMC3342028 DOI: 10.3389/fimmu.2011.00064] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 11/07/2011] [Indexed: 12/11/2022] Open
Abstract
This issue of Frontiers in Immunologic Tolerance explores barriers to tolerance from a variety of views of cells, molecules, and processes of the immune system. Our laboratory has spent over a decade focused on the migration of the cells of the immune system, and dissecting the signals that determine how and where effector and suppressive regulatory T cells traffic from one site to another in order to reject or protect allografts. These studies have led us to a greater appreciation of the anatomic structure of the immune system, and the realization that the path taken by lymphocytes during the course of the immune response to implanted organs determines the final outcome. In particular, the structures, microanatomic domains, and the cells and molecules that lymphocytes encounter during their transit through blood, tissues, lymphatics, and secondary lymphoid organs are powerful determinants for whether tolerance is achieved. Thus, the understanding of complex cellular and molecular processes of tolerance will not come from “96-well plate immunology,” but from an integrated understanding of the temporal and spatial changes that occur during the response to the allograft. The study of the precise positioning and movement of cells in lymphoid organs has been difficult since it is hard to visualize cells within their three-dimensional setting; instead techniques have tended to be dominated by two-dimensional renderings, although advanced confocal and two-photon systems are changing this view. It is difficult to precisely modify key molecules and events in lymphoid organs, so that existing knockouts, transgenics, inhibitors, and activators have global and pleiotropic effects, rather than precise anatomically restricted influences. Lastly, there are no well-defined postal codes or tracking systems for leukocytes, so that while we can usually track cells from point A to point B, it is exponentially more difficult or even impossible to track them to point C and beyond. We believe this represents one of the fundamental barriers to understanding the immune system and devising therapeutic approaches that take into account anatomy and structure as major controlling principles of tolerance.
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Affiliation(s)
- Bryna E Burrell
- Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine Baltimore, MD, USA
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First experience with the use of a recombinant CD3 immunotoxin as induction therapy in pig-to-primate xenotransplantation: the effect of T-cell depletion on outcome. Transplantation 2011; 92:641-7. [PMID: 21822171 DOI: 10.1097/tp.0b013e31822b92a5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND We have previously reported life-supporting kidney xenograft-survival greater than 80 days using a steroid-free antithymocyte globulin (ATG)-based induction regimen (ATG regimen) in a GalT-KO pig-to-baboon thymokidney (TK) model. We evaluated two induction regimens, a newly developed anti-monkey CD3 recombinant immunotoxin (anti-CD3 rIT) and an anti-human CD2 antibody (LoCD2), by assessing T-cell depletion (TCD) and graft survival. METHODS Four baboons received anti-CD3 rIT; the time course of TCD was studied in two animals and the other two received GalT-KO TK transplants. Two additional baboons underwent GalT-KO TK transplantation after treatment with LoCD2. All other treatments were identical to previous TCD studies with ATG. TCD was assessed by flow-cytometry; renal function was evaluated by serum creatinine and histology. RESULTS Baboons that received the anti-CD3 rIT died from pneumonia or cardiac failure on days 15 and 23. Both animals in the rIT group died with functioning grafts. Thymokidney grafts from baboons treated with the LoCD2 regimen were rejected by day 14. TCD levels in baboons receiving the anti-CD3 rIT regimen were 150 to 250 cells/μL for at least 14 days, whereas baboons receiving the LoCD2 recovered to more than 300 cells/μL by day 7. CONCLUSIONS The newly developed anti-CD3 rIT could be a useful TCD agent in baboons. However, optimal dosage, treatment duration, and bioactivity must be studied to avoid side effects. A LoCD2-based regimen was not effective for preventing xenogeneic rejection. Optimal TCD levels less than 250/μL during the induction period seem to be important for success of xeno-thymokidney transplantation.
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Tena A, Vallabhajosyula P, Hawley RJ, Griesemer A, Yamada K, Sachs DH. Quantification of baboon thymopoiesis in porcine thymokidney xenografts by the signal-joining T-cell receptor excision circle assay. Transplantation 2011; 91:639-44. [PMID: 21285918 DOI: 10.1097/tp.0b013e31820b6b52] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Transplantation of vascularized donor thymic tissue along with a kidney transplant has markedly improved graft survival across the discordant pig-to-baboon xenogeneic barrier. To quantify the production of baboon T cells by the porcine thymic tissue, we recently developed an assay to measure the excised DNA products of baboon T-cell receptor (TCR) gene rearrangement (signal-joining TCR excision circles, sjTREC). METHODS Initial polymerase chain reaction (PCR) analysis documented that TCR δREC-ψJα rearrangement occurs in baboons. Primers, specific to baboon sjTREC sequence were designed and used to quantify sjTREC molecules in peripheral blood mononuclear cells and thymic tissue using a quantitative PCR assay. RESULTS sjTREC levels were higher in phenotypically naïve (CD3CD45RA) T cells (650 copies/100,000 cells) than in phenotypically memory (CD3CD45RA) T cells, with sjTREC below the limit of detection (40 copies/100,000 cells). Surgical removal of the native thymus in two baboons led to a significant decrease of sjTREC in peripheral blood (from 1104 and 920 copies to 184 and 190 copies/100,000 cells, respectively), confirming the role of the thymus in maintaining the peripheral T-cell pool. In two thymectomized baboons that received porcine thymokidney xenografts, sjTREC levels remained low in the peripheral blood (<40 copies/100,000 cells), but increased to 52 and 192 copies/100,000 cells in thymic biopsies, implying that baboon thymopoiesis had begun to occur in the porcine thymic xenografts. CONCLUSIONS Baboon sjTREC can be quantified by quantitative PCR using primers specific to baboon sequence. Initial results suggest that baboon thymopoiesis occurs in vascularized porcine thymus xenografts.
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Affiliation(s)
- Aseda Tena
- Transplantation Biology Research Center, Massachusetts General Hospital, Boston, MA 02129, USA
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Qu Y, Zhang B, Liu S, Zhang A, Wu T, Zhao Y. 2-Gy whole-body irradiation significantly alters the balance of CD4+ CD25- T effector cells and CD4+ CD25+ Foxp3+ T regulatory cells in mice. Cell Mol Immunol 2010; 7:419-27. [PMID: 20871628 PMCID: PMC4002961 DOI: 10.1038/cmi.2010.45] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 07/06/2010] [Accepted: 07/07/2010] [Indexed: 12/25/2022] Open
Abstract
CD4(+)CD25(+) T regulatory (Treg) cells are critical in inducing and maintaining immunological self-tolerance as well as transplant tolerance. The effect of low doses of whole-body irradiation (WBI) on CD4(+)CD25(+)Foxp3(+) Treg cells has not been determined. The proportion, phenotypes and function of CD4(+)CD25(+) Treg cells were investigated 0.5, 5 and 15 days after euthymic, thymectomized or allogeneic bone marrow transplanted C57BL/6 mice received 2-Gy γ-rays of WBI. The 2-Gy WBI significantly enhanced the ratios of CD4(+)CD25(+) Treg cells and CD4(+)CD25(+)Foxp3(+) Treg cells to CD4(+) T cells in peripheral blood, lymph nodes, spleens and thymi of mice. The CD4(+)CD25(+) Treg cells of the WBI-treated mice showed immunosuppressive activities on the immune response of CD4(+)CD25(-) T effector cells to alloantigens or mitogens as efficiently as the control mice. Furthermore, 2-Gy γ-ray WBI significantly increased the percentage of CD4(+)CD25(+)Foxp3(+) Treg cells in the periphery of either thymectomized mice or allogeneic bone marrow transplanted mice. The in vitro assay showed that ionizing irradiation induced less cell death in CD4(+)CD25(+)Foxp3(+) Treg cells than in CD4(+)CD25(-) T cells. Thus, a low dose of WBI could significantly enhance the level of functional CD4(+)CD25(+)Foxp3(+) Treg cells in the periphery of naive or immunized mice. The enhanced proportion of CD4(+)CD25(+)Foxp3(+) Treg cells in the periphery by a low dose of WBI may make hosts more susceptible to immune tolerance induction.
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Affiliation(s)
- Yanyan Qu
- Transplantation Biology Research Division, State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
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Abstract
The thymus serves as the central organ of immunologic self-nonself discrimination. Thymocytes undergo both positive and negative selection, resulting in T cells with a broad range of reactivity to foreign antigens but with a lack of reactivity to self-antigens. The thymus is also the source of a subset of regulatory T cells that inhibit autoreactivity of T-cell clones that may escape negative selection. As a result of these functions, the thymus has been shown to be essential for the induction of tolerance in many rodent and large animal models. Proper donor antigen presentation in the thymus after bone marrow, dendritic cell, or solid organ transplantation has been shown to induce tolerance to allografts. The molecular mechanisms of positive and negative selection and regulatory T-cell development must be understood if a tolerance-inducing therapeutic intervention is to be designed effectively. In this brief and selective review, we present some of the known information on T-cell development and on the role of the thymus in experimental models of transplant tolerance. We also cite some clinical attempts to induce tolerance to allografts using pharmacologic or biologic interventions.
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Shimizu A, Yamada K. Histopathology of xenografts in pig to non-human primate discordant xenotransplantation. Clin Transplant 2010; 24 Suppl 22:11-5. [PMID: 20590687 DOI: 10.1111/j.1399-0012.2010.01270.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Xenotransplantation could provide a solution to the critical shortage of organs for transplantation in humans. Swine have been proposed as a suitable donor species. Swine organs, however, when transplanted to primates, are rapidly rejected by hyperacute rejection (HAR) and acute humoral xenograft rejection (AHXR). Both HAR and AHXR are triggered by xenoreactive natural antibodies directed against a specific epitope (galactose alpha1-3 galactose: Gal) on porcine vascular endothelium. In attempt to prevent HAR and AHXR, alpha1,3-galactosyltransferase gene knockout (GalT-KO) pigs have been produced. GalT-KO pig organs do not express the Gal epitope (antigen), and it therefore can eliminate the anti-Gal antibody--Gal antigen immunoreaction in xenotransplantation. We reported our initial study of kidney transplantation from GalT-KO miniature swine to baboons with either immunosuppression protocol or with a tolerance inducing protocol. Here, we discussed the pathology of xenografts in GalT-KO pig to non-human primate kidney transplantation.
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Affiliation(s)
- Akira Shimizu
- Transplantation Biology Research Center, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA.
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[Communication around the cancer diagnosis: patient satisfaction and process quality in French Comprehensive Cancer Centers]. Bull Cancer 2010; 97:1163-72. [PMID: 20947476 DOI: 10.1684/bdc.2010.1196] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Our survey was designed to evaluate the satisfaction of patients treated in French Comprehensive Cancer Centers (CCC) with the communication of their cancer diagnosis and treatments, and to use the data obtained to optimize current practices. METHODS One thousand six hundred (and) six CCC patients participated in a telephone survey. Eligible patients were attending a visit to a CCC for initial care of their disease (i.e. not a relapse). The questionnaire assessed patient satisfaction with the communication of diagnosis and treatment options, globally and with respect to potential individual determinants of satisfaction. FINDINGS Complete satisfaction was recorded by 77% of patients with their overall care at the CCC and by 63% of patients with the initial consultation when diagnosis was communicated and/or treatment discussed. Overall, 90% of patients were satisfied with the level of their implication in discussions about their care. A model established by Partial Least Squares (PLS) regression analysis, identified four major areas and their relative contributions to patient satisfaction: patient's relationship with their physician (64%); nature of the information provided (14%; influenced strongly by information on type, duration and practical organization of planned treatment); agenda/diary issues (14%; influenced strongly by waiting room delay); accompaniment (8%; influenced equally by support from close family and patient association/self-help groups). INTERPRETATION Overall satisfaction was high in cancer patients attending visits for initial care in French CCC. The model we devised to understand components of satisfaction could serve as a benchmark for evolution of outcomes in this field.
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Wang Y, Wang H, Wang S, Fu Y, Yang YG. Survival and function of CD47-deficient thymic grafts in mice. Xenotransplantation 2010; 17:160-5. [PMID: 20522249 DOI: 10.1111/j.1399-3089.2010.00578.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND We have previously shown that the interspecies incompatibility of CD47 plays an important role in triggering rejection of xenogeneic hematopoietic cells by macrophages. However, it remains unknown whether CD47 incompatibility also contributes to the rejection of non-hematopoietic xenografts. AIMS Here, we investigated the role of CD47 in preventing macrophage-mediated rejection of thymic epithelial cells in a mouse model of thymic transplantation across the CD47 barrier. METHODS Wild-type (WT) and CD47 KO mice were thymectomized and treated with T cell-depleting mAbs, and implanted with fetal thymus from syngeneic WT or CD47 KO donors. RESULTS Transplantation of CD47 KO mouse thymus led to T cell recovery in thymectomized, T cell-depleted WT mice. Similar to the control WT mouse thymic grafts, CD47 KO mouse thymic grafts showed a normal distribution of thymocyte subsets, and almost all of the thymocytes were recipient origin. Furthermore, histological analysis confirmed long-term survival of CD47 KO mouse thymic epithelial cells in WT mouse recipients. CONCLUSIONS These results demonstrate that, unlike hematopoietic cells, CD47 KO mouse thymus can survive and function in WT mice. Furthermore, our data implicate that the role of CD47 in xenograft rejection may differ for different types of xenografts, and that CD47 incompatibility is unlikely to impede thymic xenotransplantation, a potential approach to inducing xenotolerance, by triggering macrophage-mediated rejection.
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Affiliation(s)
- Yuantao Wang
- First Hospital of Jilin University, Changchun, Jilin, China
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41
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Griesemer AD, Hirakata A, Shimizu A, Moran S, Tena A, Iwaki H, Ishikawa Y, Schule P, Arn JS, Robson SC, Fishman JA, Sykes M, Sachs DH, Yamada K. Results of gal-knockout porcine thymokidney xenografts. Am J Transplant 2009; 9:2669-78. [PMID: 19845583 PMCID: PMC2801602 DOI: 10.1111/j.1600-6143.2009.02849.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Clinical transplantation for the treatment of end-stage organ disease is limited by a shortage of donor organs. Successful xenotransplantation could immediately overcome this limitation. The development of homozygous alpha1,3-galactosyltransferase knockout (GalT-KO) pigs removed hyperacute rejection as the major immunologic hurdle to xenotransplantation. Nevertheless, GalT-KO organs stimulate robust immunologic responses that are not prevented by immunosuppressive drugs. Murine studies show that recipient thymopoiesis in thymic xenografts induces xenotolerance. We transplanted life-supporting composite thymokidneys (composite thymus and kidneys) prepared in GalT-KO miniature swine to baboons in an attempt to induce tolerance in a preclinical xenotransplant model. Here, we report the results of seven xenogenic thymokidney transplants using a steroid-free immunosuppressive regimen that eliminated whole-body irradiation in all but one recipient. The regimen resulted in average recipient survival of over 50 days. This was associated with donor-specific unresponsiveness in vitro and early baboon thymopoiesis in the porcine thymus tissue of these grafts, suggesting the development of T-cell tolerance. The kidney grafts had no signs of cellular infiltration or deposition of IgG, and no grafts were lost due to rejection. These results show that xenogeneic thymus transplantation can support early primate thymopoiesis, which in turn may induce T-cell tolerance to solid organ xenografts.
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Affiliation(s)
- Adam D. Griesemer
- Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Atsushi Hirakata
- Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Akira Shimizu
- Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Shannon Moran
- Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Aseda Tena
- Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Hideyuki Iwaki
- Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Yoshinori Ishikawa
- Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Patrick Schule
- Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - J. Scott Arn
- Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Simon C. Robson
- Transplant Center, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Jay A. Fishman
- Division of Infectious Diseases, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Megan Sykes
- Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - David H. Sachs
- Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Kazuhiko Yamada
- Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA,Address all correspondence to: Kazuhiko Yamada, M.D. PhD., MGH-East; 13 Street, CNY-149, 9019; Boston, MA 02129. Head, Organ Transplantation Tolerance and Xenotransplantation Lab. Transplantation Biology Research Center, Massachusetts General Hospital/Harvard Medical School, Boston, USA,
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Habiro K, Sykes M, Yang YG. Induction of human T-cell tolerance to pig xenoantigens via thymus transplantation in mice with an established human immune system. Am J Transplant 2009; 9:1324-9. [PMID: 19459808 PMCID: PMC2752337 DOI: 10.1111/j.1600-6143.2009.02646.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Thymus xenotransplantation has been shown to induce tolerance to porcine xenografts in mice and to permit survival of alpha1,3Gal-transferase knockout porcine kidney xenografts for months in nonhuman primates. We evaluated the ability of porcine thymus xenotransplantation to induce human T-cell tolerance using a humanized mouse (hu-mouse) model, where a human immune system is preestablished by implantation of fetal human thymus tissue under the kidney capsule and intravenous injection of CD34(+) hematopoietic stem/progenitor cells. Human T-cell depletion with an anti-CD2 mAb following surgical removal of human thymic grafts prevented the initial rejection of porcine thymic xenografts in hu-mice. In these hu-mice, porcine thymic grafts were capable of supporting human thymopoiesis and T-cell development, and inducing human T-cell tolerance to porcine xenoantigens. Human T cells from these mice responded strongly to third-party pig, but not to the thymic donor swine leukocyte antigen (SLA)-matched pig stimulators in a mixed lymphocyte reaction (MLR) assay. Anti-pig xenoreactive antibodies declined in these hu-mice, whereas antibody levels increased in nontolerant animals that rejected porcine thymus grafts. These data show that porcine thymic xenotransplantation can induce donor-specific tolerance in immunocompetent hu-mice, supporting this approach for tolerance induction in clinical xenotransplantation.
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Affiliation(s)
- Katsuyoshi Habiro
- Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129
| | - Megan Sykes
- Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129
| | - Yong-Guang Yang
- Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, Corresponding Author: Yong-Guang Yang, MD, PhD, Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, MGH-East, Building 149-5102, 13 street, Boston, MA 02129, USA, Tel: 617/726-6959; Fax: 617/724-9892; E-mail:
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Zhang B, Zhang A, Qu Y, Liu J, Niu Z, Zhao Y. Development of mouse CD4+CD25+Foxp3+ regulatory T cells in xenogeneic pig thymic grafts. Transpl Immunol 2009; 20:180-5. [DOI: 10.1016/j.trim.2008.09.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 09/01/2008] [Accepted: 09/10/2008] [Indexed: 02/07/2023]
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Cozzi E, Bosio E, Seveso M, Rubello D, Ancona E. Xenotransplantation as a model of integrated, multidisciplinary research. Organogenesis 2009; 5:288-96. [PMID: 19568350 PMCID: PMC2659370 DOI: 10.4161/org.7578] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Accepted: 11/19/2008] [Indexed: 11/19/2022] Open
Abstract
Xenotransplantation was proposed a long time ago as a possible solution to the world-wide shortage of human organs. For years, researchers in this field have almost exclusively directed their efforts towards combating the immunological barrier that precluded long-term xenograft survival. Studies have been conducted in both small and large animal models and the most relevant results have been obtained in pre-clincal studies, specifically those utilising the pig-to-nonhuman primate combination. In this context, a better understanding of the immunological mechanisms underlying the rejection of a xenograft have allowed the identification of specific targets of intervention that have resulted in considerable improvements in survival of porcine organs or cells in nonhuman primates. However it has also become apparent that if xenotransplantation has to enter the clinical arena, a multidisciplinary approach will be needed to comprehensively tackle the different issues related to the use of a xenograft to cure human disease.In this regard, the safety, ethics and regulatory aspects of xenotransplantation are currently being aggressively addressed to enable the initiation of xenotransplantation with a favourable risk/benefit ratio.
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Affiliation(s)
- Emanuele Cozzi
- Direzione Sanitaria; Padua General Hospital; Padua, Italy; Department of Surgical and Gastroenterological Sciences; University of Padua; Padua, Italy; CORIT (Consorzio per la Ricerca sul Trapianto d'Organi); Padua, Italy; Department of Nuclear Medicine; PET Centre; S. Maria della Misericordia Hospital; Rovigo, Italy; Clinica Chirurgica III; Padua General Hospital; Padua, Italy
| | - Erika Bosio
- Direzione Sanitaria; Padua General Hospital; Padua, Italy; Department of Surgical and Gastroenterological Sciences; University of Padua; Padua, Italy; CORIT (Consorzio per la Ricerca sul Trapianto d'Organi); Padua, Italy; Department of Nuclear Medicine; PET Centre; S. Maria della Misericordia Hospital; Rovigo, Italy; Clinica Chirurgica III; Padua General Hospital; Padua, Italy
| | - Michela Seveso
- Direzione Sanitaria; Padua General Hospital; Padua, Italy; Department of Surgical and Gastroenterological Sciences; University of Padua; Padua, Italy; CORIT (Consorzio per la Ricerca sul Trapianto d'Organi); Padua, Italy; Department of Nuclear Medicine; PET Centre; S. Maria della Misericordia Hospital; Rovigo, Italy; Clinica Chirurgica III; Padua General Hospital; Padua, Italy
| | - Domenico Rubello
- Direzione Sanitaria; Padua General Hospital; Padua, Italy; Department of Surgical and Gastroenterological Sciences; University of Padua; Padua, Italy; CORIT (Consorzio per la Ricerca sul Trapianto d'Organi); Padua, Italy; Department of Nuclear Medicine; PET Centre; S. Maria della Misericordia Hospital; Rovigo, Italy; Clinica Chirurgica III; Padua General Hospital; Padua, Italy
| | - Ermanno Ancona
- Direzione Sanitaria; Padua General Hospital; Padua, Italy; Department of Surgical and Gastroenterological Sciences; University of Padua; Padua, Italy; CORIT (Consorzio per la Ricerca sul Trapianto d'Organi); Padua, Italy; Department of Nuclear Medicine; PET Centre; S. Maria della Misericordia Hospital; Rovigo, Italy; Clinica Chirurgica III; Padua General Hospital; Padua, Italy
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Fudaba Y, Onoe T, Chittenden M, Shimizu A, Shaffer JM, Bronson R, Sykes M. Abnormal regulatory and effector T cell function predispose to autoimmunity following xenogeneic thymic transplantation. THE JOURNAL OF IMMUNOLOGY 2008; 181:7649-59. [PMID: 19017953 DOI: 10.4049/jimmunol.181.11.7649] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Porcine thymus grafts support robust murine and human thymopoiesis, generating a diverse T cell repertoire that is deleted of donor and host-reactive cells, achieving specific xenograft tolerance. Positive selection is mediated exclusively by the xenogeneic thymic MHC. Although thymectomized, T cell-depleted normal mice usually remain healthy following xenogeneic thymic transplantation, thymus-grafted congenitally athymic mice frequently develop multiorgan autoimmunity. We investigated the etiology of this syndrome by adoptively transferring lymphocyte populations from fetal pig thymus-grafted BALB/c nude mice to secondary BALB/c nude recipients. Fetal pig thymus-grafted nude mice generated normal numbers of CD25(+)Foxp3(+)CD4 T cells, but these cells lacked the capacity to block autoimmunity. Moreover, thymocytes and peripheral CD4(+)CD25(-) cells from fetal pig thymus-grafted nude mice, but not those from normal mice, induced autoimmunity in nude recipients. Injection of thymic epithelial cells from normal BALB/c mice into fetal pig thymus grafts reduced autoimmunity and enhanced regulatory function of splenocytes. Our data implicate abnormalities in postthymic maturation, expansion, and/or survival of T cells positively selected by a xenogeneic MHC, as well as incomplete intrathymic deletion of thymocytes recognizing host tissue-specific Ags, in autoimmune pathogenesis. Regulatory cell function is enhanced and negative selection of host-specific thymocytes may potentially also be improved by coimplantation of recipient thymic epithelial cells in the thymus xenograft.
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Affiliation(s)
- Yasuhiro Fudaba
- Department of Surgery, Transplantation Biology Research Center, Massachusetts General Hospital/Harvard Medical School, Boston, MA 02129, USA
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Sachs DH, Sykes M, Yamada K. Achieving tolerance in pig-to-primate xenotransplantation: reality or fantasy. Transpl Immunol 2008; 21:101-5. [PMID: 19059481 DOI: 10.1016/j.trim.2008.11.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Accepted: 11/18/2008] [Indexed: 02/06/2023]
Abstract
Because the immunologic differences between species are far greater than those within species, it is likely that the amount of immunosuppression that would be required for successful xenografting would be so much greater than that now used for allografting, that the side-effects and complications would be unacceptable. Tolerance approaches to xenotransplantation would overcome this concern. Studies in humanized mouse models have demonstrated that human T cells can be tolerized to porcine xenografts, providing important proofs of principle of the potential feasibility of pig-to-primate xenograft tolerance. The results available from studies of pig-to-primate xenotransplantation to date have demonstrated that while chronic immunosuppressive drugs have not completely avoided either T cell responses or humoral rejection, approaches directed toward tolerance induction have been encouraging with regard to avoiding immunization at both of these levels.
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Affiliation(s)
- David H Sachs
- Transplantation Biology Research Center, Massachusetts General Hospital and Harvard Medical School Boston, Massachusetts, USA.
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Comparison of human T cell repertoire generated in xenogeneic porcine and human thymus grafts. Transplantation 2008; 86:601-10. [PMID: 18724231 DOI: 10.1097/tp.0b013e318182d47a] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Xenogeneic thymus transplantation is an effective approach to achieving T cell tolerance across highly disparate xenogeneic species barriers. We have previously demonstrated that phenotypically normal, specifically tolerant human T cells are generated in porcine thymic grafts. In this study, we assessed the diversity of the human T cell repertoire generated in porcine thymic xenografts. We also examined the ability of porcine thymus grafts to coexist with human thymus grafts. METHODS Fetal swine (SW) or human (HU) thymus with human fetal liver fragments were transplanted under the kidney capsule of 3Gy irradiated NOD/SCID mouse recipients. Thymus tissue was harvested approximately 16 weeks posttransplant for analysis of mixed lymphocyte reactions and spectratyping of human CD4 and CD8 single positive thymocytes. RESULTS T cell receptor beta genes of human CD4 and CD8 single positive cells developing in HU and SW thymus grafts showed similar, normal CDR3 length distributions. Human T cells developing in SW thymus grafts showed specific unresponsiveness to the major histocompatibility complex of the donor swine in mixed leukocyte reaction assays. In two of three animals receiving SW and HU thymus grafts under opposite kidney capsules, both grafts functioned. In animals with surviving SW grafts, thymocytes from the SW but not the HU grafts showed specific unresponsiveness to the SW donor. CONCLUSION Swine thymus grafts support generation of human T cells with a diverse T cell receptor repertoire. Human thymocytes in human thymus grafts are not tolerized by the presence of an additional porcine thymus, but tolerance might be achieved by postthymic encounter with porcine antigens.
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Occurrence of autoimmunity after xenothymus transplantation in T-cell-deficient mice depends on the thymus transplant technique. Transplantation 2008; 85:640-4. [PMID: 18347545 DOI: 10.1097/tp.0b013e3181613f0c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Xenothymus transplantation under the kidney capsule in athymic rodents frequently leads to multiorgan autoimmunity. Herein, we explore whether this is an intrinsic risk of xenothymus grafting or whether it depends on the transplant technique. We developed a new technique of "venous pouch" thymus grafting (heart-xenothymus) and compared this with the conventional kidney subcapsular technique (kidney-xenothymus) in a rat-into-nude-mouse model. Whereas lethal autoimmunity developed in 90% of kidney-xenothymus recipients, all heart-xenothymus grafted mice remained completely healthy. Autoimmunity in heart-xenothymus recipients was absent despite a significantly improved T-cell generation and was associated with significantly higher CD4+CD25+ T-cell frequencies and CD4+CD25+ cell Foxp3 mRNA levels than those observed in kidney-xenothymus recipients. In conclusion, we describe a novel vascular pouch technique of xenothymus transplantation that prevents the development of autoimmunity in nude mice. Our data further suggest that prevention of autoimmunity is related to a superior development of regulatory T-cells.
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Li S, Yan Y, Lin Y, Bullens DM, Rutgeerts O, Goebels J, Segers C, Boon L, Kasran A, De Vos R, Dewolf-Peeters C, Waer M, Billiau AD. Rapidly induced, T-cell–independent xenoantibody production is mediated by marginal zone B cells and requires help from NK cells. Blood 2007; 110:3926-35. [PMID: 17630353 DOI: 10.1182/blood-2007-01-065482] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
AbstractXenoantibody production directed at a wide variety of T lymphocyte–dependent and T lymphocyte–independent xenoantigens remains the major immunologic obstacle for successful xenotransplantation. The B lymphocyte subpopulations and their helper factors, involved in T-cell–independent xenoantibody production are only partially understood, and their identification will contribute to the clinical applicability of xenotransplantation. Here we show, using models involving T-cell–deficient athymic recipient mice, that rapidly induced, T-cell–independent xenoantibody production is mediated by marginal zone B lymphocytes and requires help from natural killer (NK) cells. This collaboration neither required NK-cell–mediated IFN-γ production, nor NK-cell–mediated cytolytic killing of xenogeneic target cells. The T-cell–independent IgM xenoantibody response could be partially suppressed by CD40L blockade.
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Affiliation(s)
- Shengqiao Li
- Laboratory of Experimental Transplantation, University of Leuven, Leuven, Belgium
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Abstract
The achievement of immune tolerance, a state of specific unresponsiveness to the donor graft, has the potential to overcome the current major limitations to progress in organ transplantation, namely late graft loss, organ shortage and the toxicities of chronic nonspecific immumnosuppressive therapy. Advances in our understanding of immunological processes, mechanisms of rejection and tolerance have led to encouraging developments in animal models, which are just beginning to be translated into clinical pilot studies. These advances are reviewed here and the appropriate timing for clinical trials is discussed.
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Affiliation(s)
- M Sykes
- Transplantation Biology Research Center, Bone Marrow Transplantation Section, Massachusetts General Hospital/Harvard Medical School, Boston, MA 02129, USA.
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