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Singireddy S, Tully A, Galindo J, Ayares D, Singh AK, Mohiuddin MM. Genetic Engineering of Donor Pig for the First Human Cardiac Xenotransplantation: Combatting Rejection, Coagulopathy, Inflammation, and Excessive Growth. Curr Cardiol Rep 2023; 25:1649-1656. [PMID: 37938425 DOI: 10.1007/s11886-023-01978-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/04/2023] [Indexed: 11/09/2023]
Abstract
PURPOSE OF REVIEW The first successful pig to human cardiac xenotransplantation in January 2022 represented a major step forward in the fields of heart failure, immunology, and applied genetic engineering, using a 10-gene edited (GE) pig. This review summarizes the evolution of preclinical modelling data which informed the use of each of the 10 genes modified in the 10-GE pig: GGTA1, Β4GalNT2, CMAH, CD46, CD55, TBM, EPCR, CD47, HO-1, and growth hormone receptor. RECENT FINDINGS The translation of the 10-GE pig from preclinical modelling to clinical compassionate xenotransplant use was the culmination of decades of research combating rejection, coagulopathy, inflammation, and excessive xenograft growth. Understanding these 10 genes with a view to their combinatorial effects will be useful in anticipated xenotransplant clinical trials.
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Affiliation(s)
| | - Andy Tully
- Program in Cardiac Xenotransplantation, Department of Surgery, University of Maryland, Baltimore, MD, USA
| | - Javier Galindo
- Program in Cardiac Xenotransplantation, Department of Surgery, University of Maryland, Baltimore, MD, USA
| | | | - Avneesh K Singh
- Program in Cardiac Xenotransplantation, Department of Surgery, University of Maryland, Baltimore, MD, USA
| | - Muhammad M Mohiuddin
- Program in Cardiac Xenotransplantation, Department of Surgery, University of Maryland, Baltimore, MD, USA.
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Tseng HT, Lin YW, Huang CY, Shih CM, Tsai YT, Liu CW, Tsai CS, Lin FY. Animal Models for Heart Transplantation Focusing on the Pathological Conditions. Biomedicines 2023; 11:biomedicines11051414. [PMID: 37239085 DOI: 10.3390/biomedicines11051414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/29/2023] [Accepted: 05/05/2023] [Indexed: 05/28/2023] Open
Abstract
Cardiac transplant recipients face many complications due to transplant rejection. Scientists must conduct animal experiments to study disease onset mechanisms and develop countermeasures. Therefore, many animal models have been developed for research topics including immunopathology of graft rejection, immunosuppressive therapies, anastomotic techniques, and graft preservation techniques. Small experimental animals include rodents, rabbits, and guinea pigs. They have a high metabolic rate, high reproductive rate, small size for easy handling, and low cost. Additionally, they have genetically modified strains for pathological mechanisms research; however, there is a lacuna, as these research results rarely translate directly to clinical applications. Large animals, including canines, pigs, and non-human primates, have anatomical structures and physiological states that are similar to those of humans; therefore, they are often used to validate the results obtained from small animal studies and directly speculate on the feasibility of applying these results in clinical practice. Before 2023, PubMed Central® at the United States National Institute of Health's National Library of Medicine was used for literature searches on the animal models for heart transplantation focusing on the pathological conditions. Unpublished reports and abstracts from conferences were excluded from this review article. We discussed the applications of small- and large-animal models in heart transplantation-related studies. This review article aimed to provide researchers with a complete understanding of animal models for heart transplantation by focusing on the pathological conditions created by each model.
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Affiliation(s)
- Horng-Ta Tseng
- Taipei Heart Institute, Taipei Medical University, Taipei 11031, Taiwan
- Division of Cardiology and Cardiovascular Research Center, Taipei Medical University Hospital, Taipei 11031, Taiwan
- Departments of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
| | - Yi-Wen Lin
- Institute of Oral Biology, National Yang Ming Chiao Tung University (Yangming Campus), Taipei 112304, Taiwan
| | - Chun-Yao Huang
- Taipei Heart Institute, Taipei Medical University, Taipei 11031, Taiwan
- Division of Cardiology and Cardiovascular Research Center, Taipei Medical University Hospital, Taipei 11031, Taiwan
- Departments of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
| | - Chun-Ming Shih
- Taipei Heart Institute, Taipei Medical University, Taipei 11031, Taiwan
- Division of Cardiology and Cardiovascular Research Center, Taipei Medical University Hospital, Taipei 11031, Taiwan
- Departments of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
| | - Yi-Ting Tsai
- Division of Cardiovascular Surgery, Tri-Service General Hospital, Defense Medical Center, Taipei 11490, Taiwan
| | - Chen-Wei Liu
- Department of Basic Medical Science, College of Medicine, University of Arizona, Phoenix, AZ 85721, USA
| | - Chien-Sung Tsai
- Taipei Heart Institute, Taipei Medical University, Taipei 11031, Taiwan
- Division of Cardiovascular Surgery, Tri-Service General Hospital, Defense Medical Center, Taipei 11490, Taiwan
- Department and Graduate Institute of Pharmacology, National Defense Medical Center, Taipei 11490, Taiwan
| | - Feng-Yen Lin
- Taipei Heart Institute, Taipei Medical University, Taipei 11031, Taiwan
- Division of Cardiology and Cardiovascular Research Center, Taipei Medical University Hospital, Taipei 11031, Taiwan
- Departments of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
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Mohiuddin MM, Singh AK, Goerlich CE. Preclinical rationale and current pathways to support the first human clinical trials in cardiac xenotransplantation. Hum Immunol 2023; 84:34-42. [PMID: 35851182 PMCID: PMC10154071 DOI: 10.1016/j.humimm.2022.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 06/29/2022] [Accepted: 07/07/2022] [Indexed: 01/05/2023]
Abstract
Recent initiation of the first FDA-approved cardiac xenotransplantation suggests xenotransplantation could soon become a therapeutic option for patients unable to undergo allotransplantation. Until xenotransplantation is widely applied in clinical practice, consideration of benefit versus risk and approaches to management of clinical xenografts will based at least in part on observations made in experimental xenotransplantation in non-human primates. Indeed, the decision to proceed with clinical trials reflects significant progress in last few years in experimental solid organ and cellular xenotransplantation. Our laboratory at the NIH and now at University of Maryland contributed to this progress, with heterotopic cardiac xenografts surviving more than two years and life-supporting cardiac xenografts survival up to 9 months. Here we describe our contributions to the understanding of the mechanism of cardiac xenograft rejection and development of methods to overcome past hurdles, and finally we share our opinion on the remaining barriers to clinical translation. We also discuss how the first in human xenotransplants might be performed, recipients managed, and graft function monitored.
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Improved efficiencies in the generation of multigene-modified pigs by recloning and using sows as the recipient. ZYGOTE 2021; 30:103-110. [PMID: 34176529 DOI: 10.1017/s0967199421000423] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This study was performed to improve production efficiency at the level of recipient pig and donor nuclei of transgenic cloned pigs used for xenotransplantation. To generate transgenic pigs, human endothelial protein C receptor (hEPCR) and human thrombomodulin (hTM) genes were introduced using the F2A expression vector into GalT-/-/hCD55+ porcine neonatal ear fibroblasts used as donor cells and cloned embryos were transferred to the sows and gilts. Cloned fetal kidney cells were also used as donor cells for recloning to increase production efficiency. Pregnancy and parturition rates after embryo transfer and preimplantation developmental competence were compared between cloned embryos derived from adult and fetal cells. Significantly higher parturition rates were shown in the group of sows (50.0 vs. 4.1%), natural oestrus (20.8 vs. 0%), and ovulated ovary (16.7 vs. 5.6%) compared with gilt, induced and non-ovulated, respectively (P < 0.05). When using gilts as recipients, final parturitions occurred in only the fetal cell groups and significantly higher blastocyst rates (15.1% vs. 21.3%) were seen (P < 0.05). Additionally, gene expression levels related to pluripotency were significantly higher in the fetal cell group (P < 0.05). In conclusion, sows can be recommended as recipients due to their higher efficiency in the generation of transgenic cloned pigs and cloned fetal cells also can be recommended as donor cells through correct nuclear reprogramming.
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Nowak-Terpiłowska A, Lipiński D, Hryhorowicz M, Juzwa W, Jura J, Słomski R, Mazurkiewicz N, Gawrońska B, Zeyland J. Production of ULBP1-KO pigs with human CD55 expression using CRISPR technology. JOURNAL OF APPLIED ANIMAL RESEARCH 2020. [DOI: 10.1080/09712119.2020.1735396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
| | - Daniel Lipiński
- Department of Biochemistry and Biotechnology, Poznan University of Life Sciences, Poznań, Poland
| | - Magdalena Hryhorowicz
- Department of Biochemistry and Biotechnology, Poznan University of Life Sciences, Poznań, Poland
| | - Wojciech Juzwa
- Department of Biotechnology and Food Microbiology, Poznan University of Life Sciences, Poznań, Poland
| | - Jacek Jura
- Department of Animal Reproduction, National Research Institute of Animal Production, Balice, Poland
| | - Ryszard Słomski
- Institute of Human Genetics, Polish Academy of Sciences, Poznań, Poland
| | - Natalia Mazurkiewicz
- Department of Biochemistry and Biotechnology, Poznan University of Life Sciences, Poznań, Poland
| | - Barbara Gawrońska
- Department of Biochemistry and Biotechnology, Poznan University of Life Sciences, Poznań, Poland
| | - Joanna Zeyland
- Department of Biochemistry and Biotechnology, Poznan University of Life Sciences, Poznań, Poland
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Abstract
Swine are used in biomedical research as models for biomedical research and for teaching. This chapter covers normative biology and behavior along with common and emerging swine diseases. Xenotransplantation is discussed along with similarities and differences of swine immunology.
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Affiliation(s)
- Kristi L. Helke
- Departments of Comparative Medicine and Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA
| | | | - Raimon Duran-Struuck
- Columbia Center of Translational Immunology, Department of Surgery; Institute of Comparative Medicine; Columbia University Medical Center, New York, NY, USA
| | - M. Michael Swindle
- Medical University of South Carolina, Department of Comparative Medicine and Department of Surgery, Charleston, SC, USA
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Touzot M, Obada EN, Beaudreuil S, François H, Durrbach A. Complement modulation in solid-organ transplantation. Transplant Rev (Orlando) 2014; 28:119-25. [PMID: 24996770 DOI: 10.1016/j.trre.2014.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 03/08/2014] [Indexed: 01/18/2023]
Abstract
The complement system is a major constituent of the innate immune system. It has a critical role in defense against pathogens but dysregulation of complement activation may lead to tissue injury and modulate the adaptive immune response. In organ transplantation, local complement activation is involved in hyper-acute rejection and antibody-mediated rejection. This last decade, interest in complement activation has increased due to new insights into the pathophysiology of antibody-mediated rejection, but also since the availability of news drugs that target terminal complement activation. In this review, we discuss our current understanding of how local complement activation induces acute and chronic graft injury, and review recent advances in clinical trials that block complement activation using the anti-C5 monoclonal antibody, eculizumab. Finally, we discuss how complement-targeted therapy may be integrated into our current immunosuppressive regimen and what type of patient will benefit most from this therapy.
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Affiliation(s)
- Maxime Touzot
- Nephrology Department, IFRNT, Le Kremlin-Bicêtre, France; Institut National de la Santé et de la Recherche Médicale INSERM U1014, Villejuif, France
| | | | - Severine Beaudreuil
- Nephrology Department, IFRNT, Le Kremlin-Bicêtre, France; Institut National de la Santé et de la Recherche Médicale INSERM U1014, Villejuif, France
| | - Hélène François
- Nephrology Department, IFRNT, Le Kremlin-Bicêtre, France; Institut National de la Santé et de la Recherche Médicale INSERM U1014, Villejuif, France
| | - Antoine Durrbach
- Nephrology Department, IFRNT, Le Kremlin-Bicêtre, France; Institut National de la Santé et de la Recherche Médicale INSERM U1014, Villejuif, France.
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Abstract
Seminal studies in rabbits and rodent transplantation models by Peter Medawar revealed that cellular processes, rather than humoral antibodies, are central to the acute rejection of transplanted organs, and much of basic transplantation research continues to be focused on the biology and control of these cells, which were subsequently shown to be T cells. However, the success of current immunosuppression at controlling T-cell-mediated rejection has resulted in an increasing awareness of antibody-mediated rejection in the clinic. This, in turn, has fueled an emerging interest in the biology of allospecific antibodies, the B cells that produce these antibodies, and the development of mouse models that allow their investigation. Here we summarize some of the more widely used mouse models that have been developed to study the immunobiology of alloreactivity, transplantation rejection and tolerance, and used to identify therapeutic strategies that modulate these events.
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Affiliation(s)
- Anita S Chong
- Section of Transplantation, Department of Surgery, The University of Chicago, Chicago, Illinois 60637
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Heemann U, Lutz J. Pathophysiology and treatment options of chronic renal allograft damage. Nephrol Dial Transplant 2013; 28:2438-46. [DOI: 10.1093/ndt/gft087] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Dorling A. Transplant accommodation--are the lessons learned from xenotransplantation pertinent for clinical allotransplantation? Am J Transplant 2012; 12:545-53. [PMID: 22050724 DOI: 10.1111/j.1600-6143.2011.03821.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
"Accommodation" refers to a vascularized transplant that has acquired resistance to antibody-mediated rejection (AMR). The term was coined in 1990, but the phenomenon was first described after clinical ABO-incompatible (ABOi) renal transplantation in the 1980s and is recognized as a common outcome in this context today. Because of the absence, until recently of reliable animal models of allograft accommodation, it has been studied extensively by investigators in the xenotransplantation field. With recent advances in the ability to recognize and diagnose AMR in human organs, the growth of desensitization programmes for transplantation into sensitized recipients and the availability of therapies that have the potential to promote accommodation, it is timely to review the literature in this area, identifying lessons that may inform preclinical and clinical studies in the future.
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Affiliation(s)
- A Dorling
- Medical Research Council Centre for Transplantation & Innate Immunity Section, Division of Transplantation Immunology and Mucosal Biology, King's College London, Guy's Hospital, Great Maze Pond, London, UK
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Smith RN, Colvin RB. Chronic alloantibody mediated rejection. Semin Immunol 2011; 24:115-21. [PMID: 22051115 DOI: 10.1016/j.smim.2011.09.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 09/30/2011] [Indexed: 12/15/2022]
Abstract
Alloantibodies clearly cause acute antibody mediated rejection, and all available evidence supports their pathogenic etiology in the development of chronic alloantibody mediated rejection (CAMR). But the slow evolution of this disease, the on-going immunosuppression, the variations in titer of alloantibodies, and variation in antigenic targets all complicate identifying which dynamic factors are most important clinically and pathologically. This review highlights the pathological factors related to the diagnosis of CAMR, the time course and natural history of this disease. What is known about CAMR pathogenesis is discussed including alloantibodies, the role of complement, gene activation, and Fc effector cell function. Therapy, which is problematic for this disease, is also discussed, including on-going and potential therapies and their limitations.
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Affiliation(s)
- R Neal Smith
- Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
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El-Amouri IS, Bani-Ahmad M, Tang-Feldman Y, Lin F, Ko C, Pomeroy C, Oakley OR. Increased morbidity and mortality in murine cytomegalovirus-infected mice following allogeneic bone marrow transplant is associated with reduced surface decay accelerating factor expression. Clin Exp Immunol 2010; 162:379-91. [PMID: 20840652 DOI: 10.1111/j.1365-2249.2010.04241.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Infection with cytomegalovirus (CMV) remains a significant cause of morbidity and mortality following allogeneic bone marrow transplantation (allo-BMT). The manifestations of CMV infection can range from neurological and haematological abnormalities to diminished graft survival and, in extreme cases, death. Many clinical studies have shown a direct correlation between cytomegalovirus infection and increased morbidity and mortality post allo-BMT, yet the exact mechanism is not well understood. Although driven primarily by T cell responses, the role of complement activation in acute and chronic graft-versus-host disease (GVHD) has also become more evident in recent years. The present studies were performed to examine the effects of murine cytomegalovirus (MCMV) infection on decay accelerating factor (DAF) and MCMVs role in exacerbating morbidity and mortality post-allo-BMT. Mice infected previously with a sublethal dose of MCMV (1 × 10⁵ plaque-forming units) have reduced expression of DAF on lung tissues and lymphocytes following allo-BMT. More importantly, mortality rates post-allo-BMT in recipient DAF knock-out mice receiving wild-type bone marrow are increased, similar to wild-type MCMV-infected recipient mice. Similarly, DAF knock-out mice showed greater intracellular interferon (IFN)-γ production by lung CD8 T cells, and infection with MCMV further exacerbated both intracellular IFN-γ production by CD8 T cells and mortality rates post-allo-BMT. Together, these data support the hypothesis that MCMV infection augments morbidity and mortality post-allo-BMT by reducing surface DAF expression.
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Affiliation(s)
- I S El-Amouri
- Center of Excellence in Reproductive Sciences, University of Kentucky, Lexington, 40536-0084, USA
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Expression of the decay-accelerating factor (CD55) in renal transplants--a possible prediction marker of allograft survival. Transplantation 2009; 88:457-64. [PMID: 19696627 DOI: 10.1097/tp.0b013e3181b0517d] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Decay-accelerating factor (CD55) accelerates the decay of C3 and C5 convertases, participating in classical and alternative complement activation pathways. Complement activation plays a major role in antibody-mediated rejection of allografts (AMR); C4d is used as a marker of AMR. Emerging evidence suggests an important role of CD55 in the pathogenesis of AMR. The aim of this study was to investigate the expression of CD55 in renal allografts and to correlate it with the expression of C4d, allograft survival, changes in serum creatinine (SC). METHODS More than 200 renal allograft biopsies, performed for allograft dysfunction, were assessed for peritubular capillary (PTC) C4d and CD55 expression. RESULTS We found significant correlation between changes in SC and PTC CD55 staining pattern in patients with no PTC C4d staining. In these patients, SC increased from baseline by 2.2+0.34, 1.7+0.36, and 0.93+0.24 mg/dL in negative, focal, and diffuse PTC CD55 staining subgroups, respectively. Survival of renal allografts was better in diffuse PTC CD55 staining subgroup than in negative PTC CD55 staining subgroup. CONCLUSIONS These data suggest that CD55 expression has a protective effect on PTC C4d negative renal allografts, and the pattern of PTC CD55 expression may be used as a potential marker of renal allograft survival in patients with no evidence of AMR.
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Li SZ, Qu YC, Liu BQ, Wang GY, Zhang Y, Ma ZF, Ma TX, Qiu M, Han RF. Synergistic effects of alpha-1,2-fucosyltransferase, DAF, and CD59 in suppression of xenogenic immunological responses. Xenotransplantation 2009; 16:27-33. [PMID: 19243558 DOI: 10.1111/j.1399-3089.2009.00509.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Previous studies showed that alpha-1,2-fucosyltransferase (HT), decay accelerating factor (DAF), and CD59 have an inhibitory effect on the immunological rejection of xenogenic transplantation. METHODS To investigate their possible synergistic effects in suppression of heterogeneic transplantation, we produced transgenic mouse lines expressing human HT, DAF, and/or CD59 by the standard pronuclear injection approach. PCR and Southern blot were used to identify the transgenic founder lines. Flow cytometry confirmed the high-level expression of HT, DAF, or CD59 in the transgenic mice. RESULTS The deposition of IgM, C3c, or C9 in the cardiac vascular endothelial cells of the HT, HT/CD59, and/or DAF multiple positive transgenic mice was markedly decreased. The survival time and function of the hearts of the co-transgenic mice were significantly longer and higher than that of the single HT-positive transgenic mice (P < 0.05). CONCLUSION The mice co-expressing HT/DAF or HT/CD59 could resist the hyperacute rejection better than those expressing HT alone. It is feasible to use HT and C-reactive proteins co-transgenic tissues to resist hyperacute rejection and xenograft rejection.
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Affiliation(s)
- Sheng-Zhi Li
- Tianjin Institute of Urology and Second Hospital of Tianjin Medical University, Tianjin, China
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Pavlov V, Raedler H, Yuan S, Leisman S, Kwan WH, Lalli PN, Medof ME, Heeger PS. Donor deficiency of decay-accelerating factor accelerates murine T cell-mediated cardiac allograft rejection. THE JOURNAL OF IMMUNOLOGY 2008; 181:4580-9. [PMID: 18802060 DOI: 10.4049/jimmunol.181.7.4580] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Decay-accelerating factor (DAF) is a cell surface regulator that accelerates the dissociation of C3/C5 convertases and thereby prevents the amplification of complement activation on self cells. In the context of transplantation, DAF has been thought to primarily regulate antibody-mediated allograft injury, which is in part serum complement-dependent. Based on our previously delineated link between DAF and CD4 T cell responses, we evaluated the effects of donor Daf1 (the murine homolog of human DAF) deficiency on CD8 T cell-mediated cardiac allograft rejection. MHC-disparate Daf1(-/-) allografts were rejected with accelerated kinetics compared with wild-type grafts. The accelerated rejection predominantly tracked with DAF's absence on bone marrow-derived cells in the graft and required allograft production of C3. Transplantation of Daf1(-/-) hearts into wild-type allogeneic hosts augmented the strength of the anti-donor (direct pathway) T cell response, in part through complement-dependent proliferative and pro-survival effects on alloreactive CD8 T cells. The accelerated allograft rejection of Daf1(-/-) hearts occurred in recipients lacking anti-donor Abs. The results reveal that donor DAF expression, by controlling local complement activation on interacting T cell APC partners, regulates the strength of the direct alloreactive CD8(+) T cell response. The findings provide new insights into links between innate and adaptive immunity that could be exploited to limit T cell-mediated injury to an allograft following transplantation.
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Affiliation(s)
- Vasile Pavlov
- Department of Medicine, Transplant Institute and Immunology Institute, Mount. Sinai School of Medicine, New York, NY 10029, USA
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Lin CC, Cooper DKC, Dorling A. Coagulation dysregulation as a barrier to xenotransplantation in the primate. Transpl Immunol 2008; 21:75-80. [PMID: 19000927 DOI: 10.1016/j.trim.2008.10.008] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Accepted: 10/09/2008] [Indexed: 11/28/2022]
Abstract
PURPOSE OF REVIEW The ability to generate pigs expressing a human complement regulatory protein (hCRP) and/or pigs in which the alpha1,3-galactosyltransferase gene has been knocked out (GT-KO) has largely overcome the barrier of hyperacute rejection of a pig organ transplanted into a primate. However, acute humoral xenograft rejection (AHXR), presenting as microvascular thrombosis and/or consumptive coagulopathy, remains a major hurdle to successful xenotransplantation. This review summarizes recent studies of the coagulation problems associated with xenotransplantation, and discusses potential strategies to overcome them. RECENT PROGRESS Organ transplantation into nonhuman primates from GT-KO pigs that express a hCRP are not susceptible to hyperacute rejection. Nevertheless, most recipients of GT-KO and/or hCRP transgenic pig organs develop a consumptive coagulopathy, even when the graft remains functioning. This is associated with platelet aggregation, thrombocytopenia, anemia, and a tendency to bleed. Whilst this may reflect an ongoing immune response against the graft, (as exposure to anti-nonGal antibodies in vitro induces procoagulant changes in porcine ECs, even in the absence of complement), histological examination of the graft often shows only minimal features of immune injury, unlike grafts undergoing typical AHXR. Importantly, recent in vitro studies have indicated that the coincubation of porcine endothelial cells (ECs) with human platelets activates the platelets to express tissue factor, independent of a humoral immune response. These observations suggest that the use of organs from GT-KO pigs that express a hCRP may not be sufficient to prevent the development of a coagulation disorder following xenotransplantation, even if complete immunological tolerance can be achieved. SUMMARY Both thrombotic microangiopathy and systemic consumptive coagulopathy are increasingly recognized as barriers to successful xenotransplantation. The breeding of transgenic pigs with one or more human anticoagulant genes, such as CD39 or tissue factor pathway inhibitor, is anticipated to inhibit the procoagulant changes that take place on the graft ECs, and thus may prevent or reduce platelet activation that arises as a result of immune-mediated injury. The identification of the molecular mechanisms that develop between porcine ECs and human platelets may allow pharmacological approaches to be determined that inhibit the development of thrombotic microangiopathy and consumptive coagulopathy. Hopefully, further genetic modification of the organ-source pigs, combined with systemic drug therapy to the recipient, will prolong graft survival further.
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Affiliation(s)
- Chih Che Lin
- Department of Immunology, Imperial College London, Hammersmith Hospital, London, UK
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Onzuka T, Shimizu I, Tomita Y, Iwai T, Okano S, Tominaga R. Application of cyclophosphamide-induced tolerance in alpha1,3-galactosyltransferase knockout mice presensitized with Gal alpha 1-3Gal beta-4-GlcNAc antigens. Surg Today 2008; 38:807-14. [PMID: 18751946 DOI: 10.1007/s00595-007-3715-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Accepted: 09/27/2007] [Indexed: 11/28/2022]
Abstract
PURPOSE Hyperacute rejection (HAR) mediated by the natural antibody (nAb) against Gal alpha 1-3Gal beta-4-GlcNAc (alpha Gal) is the major obstacle in xenogeneic organ transplantation. Previously, we reported the acceptance of donor heart grafts in anti-alpha Gal nAb-producing galactosyltransferase knockout (GalT KO) mice after cyclophosphamide (CP)-induced tolerance conditioning. In the present study, we applied our tolerance induction conditioning in presensitized recipient mice. METHODS GalT KO (alpha Gal(-/-), H-2(b/d)) recipient mice were presensitized with alpha Gal(+) rabbit red blood cells (RRBCs). Presensitized or nonsensitized recipient mice were treated with CP-induced tolerance conditioning, consisting of AKR (alpha Gal(+/+), H-2(k)) spleen cells (SC), CP, busulfan (BU), and AKR bone marrow cells (BMC). We assessed the survival of donor hearts and skin grafts and analyzed the production of anti-alpha Gal Abs by flow cytometry. RESULTS Donor mixed chimerism was achieved in the presensitized GalT KO mice treated with CP-induced tolerance conditioning. In parallel with the disappearance of anti-alpha Gal Abs, permanent acceptance of donor heart grafts and skin grafts was observed in presensitized and GalT KO mice treated with CP-induced tolerance conditioning. CONCLUSIONS Both B-cell and T-cell tolerance was achieved in the presence of a higher titer of anti-alpha Gal Abs after treatment with CP-induced tolerance conditioning.
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Affiliation(s)
- Tatsushi Onzuka
- Department of Cardiovascular Surgery, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
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Smith RN, Kawai T, Boskovic S, Nadazdin O, Sachs DH, Cosimi AB, Colvin RB. Four stages and lack of stable accommodation in chronic alloantibody-mediated renal allograft rejection in Cynomolgus monkeys. Am J Transplant 2008; 8:1662-72. [PMID: 18557724 PMCID: PMC2796366 DOI: 10.1111/j.1600-6143.2008.02303.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The etiology of immunologically mediated chronic renal allograft failure is unclear. One cause is thought to be alloantibodies. Previously in Cynomolgus monkeys, we observed a relationship among donor-specific alloantibodies (DSA), C4d staining, allograft glomerulopathy, allograft arteriopathy and progressive renal failure. To define the natural history of chronic antibody-mediated rejection and its effect on renal allograft survival, we now extend this report to include 417 specimens from 143 Cynomolgus monkeys with renal allografts. A subset of animals with long-term renal allografts made DSA (48%), were C4d positive (29%), developed transplant glomerulopathy (TG) (22%) and chronic allograft arteriopathy (CAA) (19%). These four features were highly correlated and associated with statistically significant shortened allograft survival. Acute cellular rejection, either Banff type 1 or 2, did not correlate with alloantibodies, C4d deposition or TG. However, endarteritis (Banff type 2) correlated with later CAA. Sequential analysis identified four progressive stages of chronic antibody-mediated rejection: (1) DSA, (2) deposition of C4d, (3) TG and (4) rising creatinine/renal failure. These new findings provide strong evidence that chronic antibody-mediated rejection develops without enduring stable accommodation, progresses through four defined clinical pathological stages and shortens renal allograft survival.
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Cornell LD, Smith RN, Colvin RB. Kidney transplantation: mechanisms of rejection and acceptance. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2008; 3:189-220. [PMID: 18039144 DOI: 10.1146/annurev.pathmechdis.3.121806.151508] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We describe the molecular and cellular mechanisms believed to be responsible for the rejection of renal allografts, including acute T cell-mediated rejection, acute antibody-mediated (humoral) rejection, rejection mediated by the innate immune system, and chronic rejection. We present mechanisms of graft acceptance, including accommodation, regulation, and tolerance. Studies in animals have replicated many pathologic features of acute and chronic rejection. We illuminate the pathogenesis of human pathology by reflection from experimental models.
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Affiliation(s)
- Lynn D Cornell
- Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
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20
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Liu B, Cheng C, Wu Y, Wei J, Li G, Ma T. Transgenic mice designed to express human alpha-1,2-fucosyltransferase in combination of human DAF and CD59 to avoid xenograft rejection. SCIENCE IN CHINA. SERIES C, LIFE SCIENCES 2008; 51:199-204. [PMID: 18246307 DOI: 10.1007/s11427-008-0019-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Accepted: 11/29/2007] [Indexed: 11/24/2022]
Abstract
The expression of human alpha-1,2-fucosyltransferase (HT) or complement regulatory proteins has been proved as an strategy to overcome hypercute rejection in discordant xenogeneic organ transplantation. In this study, we examined whether peripheral blood mononuclear cells (PBMCs) from polytransgenic mice expressing the human HT, and complement regulatory proteins (DAF and CD59), can provide more effective protection against xenograft rejection. Transgenic mice were produced by co-injection of gene constructs for human HT, DAF and/or CD59. Flow Cytometry (FCM) was used to screen the positive transgenic mice. PBMCs from transgenic mice were incubated with 15% human serum to evaluate natural antibody binding, complement activation and expression of adhesion molecules. Three transgenes were strongly expressed in PBMCs of transgenic mice, and HT expression significantly reduced expression of the major xenoepitope galactose-alpha-1,3-galactose (alpha-Gal). Functional studies with PBMCs showed that co-expression of HT and DAF or CD59 markedly increased their resistance to human serum-mediated cytolysis when compared with single transgenic PBMCs. Moreover, the combined expression of triple transgenes in PBMCs led to the greatest protection against human serum-mediated cytolysis, avoided hyperacute rejection and reduced expression of adhesion molecules. Strong co-expression of triple transgenes was completely protected from xenograft hyperacute rejection and partially inhibited acute vascular rejection. The studies suggest that engineering mice to express triple molecules represents an critical step toward prolonging xenograft survival and might be more suitable for xenotransplantation.
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Affiliation(s)
- BingQian Liu
- Department of Urology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
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21
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Distribution of the alphaGal- and the non-alphaGal T-antigens in the pig kidney: potential targets for rejection in pig-to-man xenotransplantation. Immunol Cell Biol 2008; 86:363-71. [PMID: 18301385 DOI: 10.1038/icb.2008.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Carbohydrate antigens, present on pig vascular endothelial cells, seem to be the prime agents responsible for graft rejection, and although genetically modified animals that express less amounts of carbohydrate antigen are available, it is still useful to decide the localization of the reactive xenoantigens in organs contemplated for xenotransplantation. Here we compare the distribution in pig kidney of antigens important in xenograft destruction, namely the Galalpha1-3Gal (alphaGal) glycans, with the localization of the T-antigen (Galbeta1-3GalNAc). The alpha-galactose-specific lectin Griffonia simplicifolia isolectin 1B4 was used to detect the Galalpha1-3Gal glycans, whereas Arachis hypogaea (PNA) lectin and a monoclonal antibody (3C9) detected T-antigen. In addition, two vascular markers (anti-caveolin-1 and anti-von Willebrand factor) served to identify vascular structures of the kidney. Both conventional fluorescence and confocal microscopy were used to distinguish lectin and immunohistochemical staining. On the basis of fluorescence signals, the results indicate that the carbohydrate antigens are heterogeneously distributed in the pig kidney. alphaGal epitopes were sparse in the capillary loops forming the glomeruli and in the capillaries surrounding the convoluted tubules, but showed stronger staining in capillaries surrounding the limbs of Henle. In addition, the brush border and basement membranes of the convoluted tubules strongly reacted with the GS1-B4-lectin. Finally, the Galalpha1-3Gal glycans were also present on epithelial cells of the large collecting tubules. Regarding the T-antigen, PNA and 3C9 reacted with different glomerular cells, whereas both reacted strongly with the endothelial cells lining the large kidney vessels. Human serum incubation of pig kidney sections, in which the alphaGal epitopes were blocked by unconjugated GS1-B4, showed staining of the same vascular structures as were obtained after incubation with the T-antigen-detecting agents. The study thus proves a complex spatial distribution of carbohydrate antigens relevant for xenotransplantation of pig kidney.
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22
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Sykes M. 2007 IXA Presidential Address. Progress toward an ideal source animal: opportunities and challenges in a changing world. Xenotransplantation 2008; 15:7-13. [DOI: 10.1111/j.1399-3089.2008.00441.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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23
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Park CG, Kim JS, Kim YH. Current Status and Future Perspectives of Xenotransplantation and Stem Cell Research in Transplantation Field. JOURNAL OF THE KOREAN MEDICAL ASSOCIATION 2008. [DOI: 10.5124/jkma.2008.51.8.732] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Chung-Gyu Park
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Korea.
| | - Jung-Sik Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Korea.
| | - Yong-Hee Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Korea.
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Ding JW, Zhou T, Ma L, Yin D, Shen J, Ding CPY, Tang IY, Byrne GW, Chong AS. Expression of complement regulatory proteins in accommodated xenografts induced by anti-alpha-Gal IgG1 in a rat-to-mouse model. Am J Transplant 2008; 8:32-40. [PMID: 17973967 DOI: 10.1111/j.1600-6143.2007.02016.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Anti-graft antibodies are often associated with graft rejection. Under special conditions, grafts continue to function normally even in the presence of anti-graft antibodies and complement. This condition is termed accommodation. We developed a xenograft accommodation model in which baby Lewis rat hearts are transplanted into Rag/GT-deficient mice, and accommodation is induced by repeated i.v. injections of low-dose anti-alpha-Gal IgG(1). The accommodated grafts survived a bolus dose of anti-alpha-Gal IgG(1), while freshly transplanted second grafts were rejected. To study the mechanism of anti-alpha-Gal IgG(1)-mediated accommodation, both real-time PCR and immunohistochemical staining revealed elevated expression of DAF, Crry and CD59 in the accommodated grafts. In vitro exposure of rat endothelial cells to anti-alpha-Gal IgG(1) also induced the up-regulation of DAF, Crry and CD59, as revealed by Western blot analyses, and was associated with an acquired resistance to antibody and complement-mediated lysis in vitro. Collectively, these studies suggest that the up-regulation of complement regulatory proteins may abrogate complement-mediated rejection and permit the development of xenograft accommodation.
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Affiliation(s)
- J Wen Ding
- Section of Transplantation, Department of Surgery, University of Chicago, Chicago, IL, USA
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25
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Yang YG, Sykes M. Xenotransplantation: current status and a perspective on the future. Nat Rev Immunol 2007; 7:519-31. [PMID: 17571072 DOI: 10.1038/nri2099] [Citation(s) in RCA: 231] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Xenotransplantation using pigs as the transplant source has the potential to resolve the severe shortage of human organ donors. Although the development of relatively non-toxic immunosuppressive or tolerance-inducing regimens will be required to justify clinical trials using pig organs, recent advances in our understanding of the biology of xenograft rejection and zoonotic infections, and the generation of alpha1,3-galactosyltransferase-deficient pigs have moved this approach closer to clinical application. This Review highlights the major obstacles impeding the translation of xenotransplantation into clinical therapies and the potential solutions, providing a perspective on the future of clinical xenotransplantation.
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Affiliation(s)
- Yong-Guang Yang
- Bone Marrow Transplantation Section, Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02129, USA
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26
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Weeks C, Moratz C, Zacharia A, Stracener C, Egan R, Peckham R, Moore FD, Tsokos GC. Decay-accelerating factor attenuates remote ischemia-reperfusion-initiated organ damage. Clin Immunol 2007; 124:311-27. [PMID: 17631050 DOI: 10.1016/j.clim.2007.05.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2007] [Revised: 05/04/2007] [Accepted: 05/08/2007] [Indexed: 01/28/2023]
Abstract
Complement activation contributes to the expression of local and remote organ injury in animal models of ischemia-reperfusion (IR). We demonstrate here that a soluble form of decay-accelerating factor (DAF) protects normal C57Bl/6 and autoimmunity-prone B6.MRL/lpr mice subjected to hindlimb IR from remote intestinal and lung injury without affecting the degree of local skeletal muscle injury. In addition, DAF treatment attenuates remote organ injury in mice subjected to mesenteric IR. Soluble DAF allowed the deposition of complement 3 in local and remote injury sites while it limited the presence of terminal membrane attack complex and did not increase animal susceptibility to sepsis. These data provide evidence that soluble DAF might offer clinical benefit to patients suffering remote intestinal or lung damage in response to muscle or other organ injury.
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Affiliation(s)
- Christine Weeks
- Department of Surgery, Brigham and Women's Hospital, Boston, MA 02115, USA
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27
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Zahorsky-Reeves JL, Kearns-Jonker MK, Lam TT, Jackson JR, Morris RE, Starnes VA, Cramer DV. The xenoantibody response and immunoglobulin gene expression profile of cynomolgus monkeys transplanted with hDAF-transgenic porcine hearts. Xenotransplantation 2007; 14:135-44. [PMID: 17381688 DOI: 10.1111/j.1399-3089.2007.00381.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Recent work has indicated a role for anti-Gal alpha 1-3Gal (Gal) and anti-non-Gal xenoantibodies in the primate humoral rejection response against human-decay accelerating factor (hDAF) transgenic pig organs. Our laboratory has shown that anti-porcine xenograft antibodies in humans and non-human primates are encoded by a small number of germline IgV(H) progenitors. In this study, we extended our analysis to identify the IgV(H) genes encoding xenoantibodies in immunosuppressed cynomolgus monkeys (Macaca fascicularis) transplanted with hDAF-transgenic pig organs. METHODS Three immunosuppressed monkeys underwent heterotopic heart transplantation with hDAF porcine heart xenografts. Two of three animals were given GAS914, a poly-L-lysine derivative shown to bind to anti-Gal xenoantibodies and neutralize them. One animal rejected its heart at post-operative day (POD) 39; a second animal rejected the transplanted heart at POD 78. The third monkey was euthanized on POD 36 but the heart was not rejected. Peripheral blood leukocytes (PBL) and serum were obtained from each animal before and at multiple time points after transplantation. We analyzed the immune response by enzyme-linked immunosorbent assay (ELISA) to confirm whether anti-Gal or anti-non-Gal xenoantibodies were induced after graft placement. Immunoglobulin heavy-chain gene (V(H)) cDNA libraries were then produced and screened. We generated soluble single-chain antibodies (scFv) to establish the binding specificity of the cloned immunoglobulin genes. RESULTS Despite immunosuppression, which included the use of the polymer GAS914, the two animals that rejected their hearts showed elevated levels of cytotoxic anti-pig red blood cell (RBC) antibodies and anti-pig aortic endothelial cell (PAEC) antibodies. The monkey that did not reject its graft showed a decline in serum anti-RBC, anti-PAEC, and anti-Gal xenoantibodies when compared with pre-transplant levels. A V(H)3 family gene with a high level of sequence similarity to an allele of V(H)3-11, designated V(H)3-11(cyno), was expressed at elevated levels in the monkey that was not given GAS914 and whose graft was not rejected until POD 78. IgM but not IgG xenoantibodies directed at N-acetyl lactosamine (a precursor of the Gal epitope) were also induced in this animal. We produced soluble scFv from this new gene to determine whether this antibody could bind to the Gal carbohydrate, and demonstrated that this protein was capable of blocking the binding of human serum xenoantibody to Gal oligosaccharide, as had previously been shown with human V(H)3-11 scFv. CONCLUSIONS DAF-transgenic organs transplanted into cynomolgus monkeys induce anti-Gal and anti-non-Gal xenoantibody responses mediated by both IgM and IgG xenoantibodies. Anti-non-Gal xenoantibodies are induced at high levels in animals treated with GAS914. Antibodies that bind to the Gal carbohydrate and to N-acetyl lactosamine are induced in the absence of GAS914 treatment. The animal whose heart remained beating for 78 days demonstrated increased usage of an antibody encoded by a germline progenitor that is structurally related, but distinct from IGHV311. This antibody binds to the Gal carbohydrate but does not induce the rapid rejection of the xenograft when expressed at high levels as early as day 8 post-transplantation.
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Affiliation(s)
- Joanne L Zahorsky-Reeves
- Cardiothoracic Surgery Research, The Saban Research Institute of Childrens Hospital Los Angeles, The Keck School of Medicine, University of Southern California, Los Angeles, CA 90027, USA
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Stussi G, West L, Cooper DKC, Seebach JD. ABO-incompatible allotransplantation as a basis for clinical xenotransplantation. Xenotransplantation 2007; 13:390-9. [PMID: 16925662 DOI: 10.1111/j.1399-3089.2006.00324.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The 8th Congress of the International Xenotransplantation Association (IXA), held in Goteborg in September, 2005, immediately followed the 2nd International Symposium on ABO-Incompatibility in Transplantation, both congresses organized by Michael Breimer and Lennart Rydberg. The Proceedings of the Symposium on ABO-Incompatibility in Transplantation have been published (Xenotransplantation 2006; 13 (2)). The present paper provides an overview of a workshop held at the 8th Congress of the IXA, and highlights the immunological concepts emerging from ABO-incompatible allotransplants and discusses them in relation to xenotransplantation. Using specified immunomodulatory protocols, ABO-incompatible solid organ allotransplantation has become a clinical reality for a small number of patients over the last two decades. ABO-incompatible adult kidney and infant heart transplants have similar patient and graft survivals as their ABO-compatible counterparts. In contrast, ABO-incompatibility is present in up to 30% of all patients receiving hematopoietic stem cell transplants in the absence of specific immunomodulation, without affecting overall survival. Consequently, ABO-incompatible solid organ transplants and hematopoietic stem cell transplants may serve as in vivo models to elucidate the immunological mechanisms of accommodation and/or tolerance in the clinical setting. Because of similarities in the immunological hurdles that need to be overcome, knowledge obtained from ABO-incompatible allotransplantation might further promote advances in the field of xenotransplantation. The similarities and differences between ABO-incompatible allotransplantation and xenotransplantation are discussed.
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Affiliation(s)
- Georg Stussi
- Laboratory for Transplantation Immunology, Department of Internal Medicine, University Hospital Zürich, Zürich, Switzerland
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29
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Liu D, Kobayashi T, Onishi A, Furusawa T, Iwamoto M, Suzuki S, Miwa Y, Nagasaka T, Maruyama S, Kadomatsu K, Uchida K, Nakao A. Relation between human decay-accelerating factor (hDAF) expression in pig cells and inhibition of human serum anti-pig cytotoxicity: value of highly expressed hDAF for xenotransplantation. Xenotransplantation 2007; 14:67-73. [PMID: 17214706 DOI: 10.1111/j.1399-3089.2006.00365.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Although the successful production of alpha1,3-galactosyltransferase-knockout (GT-KO) pigs has increased expectations of clinical xenotransplantation, additional modifications of genetically engineered pigs are still being explored, because even GT-KO pigs are incapable of inhibiting the host's immunological response completely. One of the potential candidates is a complement-regulatory protein, such as human decay-accelerating factor (hDAF). However, there are few reports on how high the expression level of hDAF in pig cells would be required for suppression of complement activation. The purpose of this study was to examine the relationship between the level of hDAF expression and its inhibitory effect on human serum cytotoxicity. METHODS An expression (pCAGGS) vector containing the hDAF gene was transfected into pig fibroblasts using an electroporation system (Gene Pulser II). Forty-eight to fifty-two hours after transfection, the cells were stained with FITC-labeled anti-hDAF antibody and then applied to the cell sorter. hDAF-transfected cells with various expression levels were collected by gating on fluorescence intensity. The level of hDAF expression was determined relative to that in human control endothelial cells. Collected cells expressing x1, x5, x10, x15 and x30 hDAF were incubated into 96-well plates for 16 h, and the cells were subjected to 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide (MTT) assay. RESULTS hDAF expression levels in transfected cells at the time of MTT assay (16 h after sorting) were comparable to those immediately after sorting. hDAF expression in pig cells five times higher than in human endothelial cells was effective in inhibiting complement-dependent cytotoxicity of most human sera. However, 15- to 30-fold expression of hDAF was required for effective inhibition of human sera with the highest cytotoxic capacity. CONCLUSIONS A much higher level of hDAF expression in pig cells than previously considered necessary might be required to provide additional benefit in inhibiting antibody-mediated rejection. Genetically engineered pigs that express very high levels of hDAF would be beneficial for xenotransplantation.
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Affiliation(s)
- DaGe Liu
- Department of Surgery II, Nagoya University School of Medicine, Nagoya, Japan
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30
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Abstract
Recently, Galalpha1-3Galbeta1-4GlcNAc (Gal) knockout (k/o) pigs have been developed using genetic cloning technologies. This remarkable achievement has generated great enthusiasm in xenotransplantation studies. This review summarizes the current status of nonhuman primate experiments using Gal k/o pig organs. Briefly, when Gal k/o pig organs are transplanted into primates, hyperacute rejection does not occur. Although graft survival has been prolonged up to a few months in some cases, the overall results were not better than those using Gal-positive pig organs with human complement regulatory protein transgenes. Gal k/o pig kidneys rapidly developed rejection which was associated with increased anti-non-Gal antibodies. Although the precise mechanisms of Gal k/o pig organ rejection are not clear, it could result from incomplete deletion of Gal, up-regulation of new antigen (non-Gal antigen) and/or production of non-Gal antibodies. Future work in xenotransplantation should place emphasis on further modification of donors, such as combining human complement regulatory genes with Gal k/o, deleting non-Gal antigens and adding protective/surviving genes or a gene that inhibits coagulation. Induction of donor-specific T- and B-cell tolerance and promotion of accommodation are also warranted.
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Affiliation(s)
- R Zhong
- Department of Surgery, University of Western Ontario, Multi-Organ Transplant Program, London Health Sciences Centre, Transplantation Group, Robarts Research Institute, London, Ontario, Canada
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Tomita Y, Shimizu I, Iwai T, Zhang QW, Okano S, Kajiwara T, Onzuka T, Tominaga R. Application of chimerism-based drug-induced tolerance to rat into mouse xenotransplantation. Scand J Immunol 2006; 64:392-7. [PMID: 16970680 DOI: 10.1111/j.1365-3083.2006.01831.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The current critical shortage of human donor organs has stimulated the feasibility of the xenogenic transplantation, such as swine to primate. We have previously reported the induction of donor-specific tolerance in MHC-disparated recipient mice by using our cyclophosphamide (CP)-induced tolerance conditioning. In this study, we examined the efficacy of our CP-induced tolerance conditioning in xenogenic transplantation model. F344 rats and B10 mice were used as donors and recipients. Recipient mice were treated with donor spleen cells, CP, Busulfan and bone marrow cells, with or without prior NK-cell depletion. Donor mixed chimerism, and the presence of donor reactive T-cell population were analysed by flow cytometry. The survival of the donor skin grafts were observed after the conditioning. Donor mixed chimerism was temporary induced but terminated at 10 weeks after treatments. Donor-specific prolongation of the skin graft survival was observed after the treatments, however, grafts were rejected in the long term. NK-cell depletion, prior to the treatments, did not affect the levels of the mixed chimerism or graft prolongation. The donor-reactive recipient T-cell population was remained the same level as the untreated mice, suggesting the failure of the induction of the central T-cell tolerance. Thus, partial efficacy of our CP-induced tolerance treatments in the rat to mice xenotransplantation was observed. Our results suggested that the additional treatments were required to establish the stable xenogenic tolerance.
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Affiliation(s)
- Y Tomita
- Department of Cardiovascular Surgery, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
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Affiliation(s)
- Reto M Baertschiger
- Surgical Research Unit, Department of Surgery, University Hospital Geneva, Geneva, Switzerland
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