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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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Cai Y, Folkerts G, Braber S. Non-Digestible Oligosaccharides: A Novel Treatment for Respiratory Infections? Nutrients 2022; 14:nu14235033. [PMID: 36501062 PMCID: PMC9736878 DOI: 10.3390/nu14235033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 11/29/2022] Open
Abstract
Emerging antimicrobial resistance in respiratory infections requires novel intervention strategies. Non-digestible oligosaccharides (NDOs) are a diverse group of carbohydrates with broad protective effects. In addition to promoting the colonization of beneficial gut microbiota and maintaining the intestinal homeostasis, NDOs act as decoy receptors, effectively blocking the attachment of pathogens on host cells. NDOs also function as a bacteriostatic agent, inhibiting the growth of specific pathogenic bacteria. Based on this fact, NDOs potentiate the actions of antimicrobial drugs. Therefore, there is an increasing interest in characterizing the anti-infective properties of NDOs. This focused review provides insights into the mechanisms by which representative NDOs may suppress respiratory infections by targeting pathogens and host cells. We summarized the most interesting mechanisms of NDOs, including maintenance of gut microbiota homeostasis, interference with TLR-mediated signaling, anti-oxidative effects and bacterial toxin neutralization, bacteriostatic and bactericidal effects, and anti-adhesion or anti-invasive properties. A detailed understanding of anti-infective mechanisms of NDOs against respiratory pathogens may contribute to the development of add-on therapy or alternatives to antimicrobials.
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Affiliation(s)
- Yang Cai
- Department of Pharmacology, School of Medicine, Southeast University, Nanjing 210009, China
- Correspondence: (Y.C.); (S.B.)
| | - Gert Folkerts
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Saskia Braber
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584 CG Utrecht, The Netherlands
- Correspondence: (Y.C.); (S.B.)
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Galili U. Biosynthesis of α-Gal Epitopes (Galα1-3Galβ1-4GlcNAc-R) and Their Unique Potential in Future α-Gal Therapies. Front Mol Biosci 2021; 8:746883. [PMID: 34805272 PMCID: PMC8601398 DOI: 10.3389/fmolb.2021.746883] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 09/21/2021] [Indexed: 11/19/2022] Open
Abstract
The α-gal epitope is a carbohydrate antigen which appeared early in mammalian evolution and is synthesized in large amounts by the glycosylation enzyme α1,3galactosyltransferase (α1,3GT) in non-primate mammals, lemurs, and New-World monkeys. Ancestral Old-World monkeys and apes synthesizing α-gal epitopes underwent complete extinction 20–30 million years ago, and their mutated progeny lacking α-gal epitopes survived. Humans, apes, and Old-World monkeys which evolved from the surviving progeny lack α-gal epitopes and produce the natural anti-Gal antibody which binds specifically to α-gal epitopes. Because of this reciprocal distribution of the α-gal epitope and anti-Gal in mammals, transplantation of organs from non-primate mammals (e.g., pig xenografts) into Old-World monkeys or humans results in hyperacute rejection following anti-Gal binding to α-gal epitopes on xenograft cells. The in vivo immunocomplexing between anti-Gal and α-gal epitopes on molecules, pathogens, cells, or nanoparticles may be harnessed for development of novel immunotherapies (referred to as “α-gal therapies”) in various clinical settings because such immune complexes induce several beneficial immune processes. These immune processes include localized activation of the complement system which can destroy pathogens and generate chemotactic peptides that recruit antigen-presenting cells (APCs) such as macrophages and dendritic cells, targeting of antigens presenting α-gal epitopes for extensive uptake by APCs, and activation of recruited macrophages into pro-reparative macrophages. Some of the suggested α-gal therapies associated with these immune processes are as follows: 1. Increasing efficacy of enveloped-virus vaccines by synthesizing α-gal epitopes on vaccinating inactivated viruses, thereby targeting them for extensive uptake by APCs. 2. Conversion of autologous tumors into antitumor vaccines by expression of α-gal epitopes on tumor cell membranes. 3. Accelerating healing of external and internal injuries by α-gal nanoparticles which decrease the healing time and diminish scar formation. 4. Increasing anti-Gal–mediated protection against zoonotic viruses presenting α-gal epitopes and against protozoa, such as Trypanosoma, Leishmania, and Plasmodium, by vaccination for elevating production of the anti-Gal antibody. The efficacy and safety of these therapies were demonstrated in transgenic mice and pigs lacking α-gal epitopes and producing anti-Gal, raising the possibility that these α-gal therapies may be considered for further evaluation in clinical trials.
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Affiliation(s)
- Uri Galili
- Department of Medicine, Rush University Medical Center, Chicago, IL, United States
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In Situ "Humanization" of Porcine Bioprostheses: Demonstration of Tendon Bioprostheses Conversion into Human ACL and Possible Implications for Heart Valve Bioprostheses. Bioengineering (Basel) 2021; 8:bioengineering8010010. [PMID: 33445522 PMCID: PMC7826727 DOI: 10.3390/bioengineering8010010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/06/2021] [Accepted: 01/07/2021] [Indexed: 11/21/2022] Open
Abstract
This review describes the first studies on successful conversion of porcine soft-tissue bioprostheses into viable permanently functional tissue in humans. This process includes gradual degradation of the porcine tissue, with concomitant neo-vascularization and reconstruction of the implanted bioprosthesis with human cells and extracellular matrix. Such a reconstruction process is referred to in this review as “humanization”. Humanization was achieved with porcine bone-patellar-tendon-bone (BTB), replacing torn anterior-cruciate-ligament (ACL) in patients. In addition to its possible use in orthopedic surgery, it is suggested that this humanization method should be studied as a possible mechanism for converting implanted porcine bioprosthetic heart-valves (BHV) into viable tissue valves in young patients. Presently, these patients are only implanted with mechanical heart-valves, which require constant anticoagulation therapy. The processing of porcine bioprostheses, which enables humanization, includes elimination of α-gal epitopes and partial (incomplete) crosslinking with glutaraldehyde. Studies on implantation of porcine BTB bioprostheses indicated that enzymatic elimination of α-gal epitopes prevents subsequent accelerated destruction of implanted tissues by the natural anti-Gal antibody, whereas the partial crosslinking by glutaraldehyde molecules results in their function as “speed bumps” that slow the infiltration of macrophages. Anti-non gal antibodies produced against porcine antigens in implanted bioprostheses recruit macrophages, which infiltrate at a pace that enables slow degradation of the porcine tissue, neo-vascularization, and infiltration of fibroblasts. These fibroblasts align with the porcine collagen-fibers scaffold, secrete their collagen-fibers and other extracellular-matrix (ECM) components, and gradually replace porcine tissues degraded by macrophages with autologous functional viable tissue. Porcine BTB implanted in patients completes humanization into autologous ACL within ~2 years. The similarities in cells and ECM comprising heart-valves and tendons, raises the possibility that porcine BHV undergoing a similar processing, may also undergo humanization, resulting in formation of an autologous, viable, permanently functional, non-calcifying heart-valves.
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Host Synthesized Carbohydrate Antigens on Viral Glycoproteins as "Achilles' Heel" of Viruses Contributing to Anti-Viral Immune Protection. Int J Mol Sci 2020; 21:ijms21186702. [PMID: 32933166 PMCID: PMC7555091 DOI: 10.3390/ijms21186702] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 09/09/2020] [Accepted: 09/09/2020] [Indexed: 01/10/2023] Open
Abstract
The glycans on enveloped viruses are synthesized by host-cell machinery. Some of these glycans on zoonotic viruses of mammalian reservoirs are recognized by human natural antibodies that may protect against such viruses. These antibodies are produced mostly against carbohydrate antigens on gastrointestinal bacteria and fortuitously, they bind to carbohydrate antigens synthesized in other mammals, neutralize and destroy viruses presenting these antigens. Two such antibodies are: anti-Gal binding to α-gal epitopes synthesized in non-primate mammals, lemurs, and New World monkeys, and anti-N-glycolyl neuraminic acid (anti-Neu5Gc) binding to N-glycolyl-neuraminic acid (Neu5Gc) synthesized in apes, Old World monkeys, and many non-primate mammals. Anti-Gal appeared in Old World primates following accidental inactivation of the α1,3galactosyltransferase gene 20–30 million years ago. Anti-Neu5Gc appeared in hominins following the inactivation of the cytidine-monophosphate-N-acetyl-neuraminic acid hydroxylase gene, which led to the loss of Neu5Gc <6 million-years-ago. It is suggested that an epidemic of a lethal virus eliminated ancestral Old World-primates synthesizing α-gal epitopes, whereas few mutated offspring lacking α-gal epitopes and producing anti-Gal survived because anti-Gal destroyed viruses presenting α-gal epitopes, following replication in parental populations. Similarly, anti-Neu5Gc protected few mutated hominins lacking Neu5Gc in lethal virus epidemics that eliminated parental hominins synthesizing Neu5Gc. Since α-gal epitopes are presented on many zoonotic viruses it is suggested that vaccines elevating anti-Gal titers may be of protective significance in areas endemic for such zoonotic viruses. This protection would be during the non-primate mammal to human virus transmission, but not in subsequent human to human transmission where the virus presents human glycans. In addition, production of viral vaccines presenting multiple α-gal epitopes increases their immunogenicity because of effective anti-Gal-mediated targeting of vaccines to antigen presenting cells for extensive uptake of the vaccine by these cells.
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Hryhorowicz M, Lipiński D, Hryhorowicz S, Nowak-Terpiłowska A, Ryczek N, Zeyland J. Application of Genetically Engineered Pigs in Biomedical Research. Genes (Basel) 2020; 11:genes11060670. [PMID: 32575461 PMCID: PMC7349405 DOI: 10.3390/genes11060670] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/16/2020] [Accepted: 06/17/2020] [Indexed: 02/07/2023] Open
Abstract
Progress in genetic engineering over the past few decades has made it possible to develop methods that have led to the production of transgenic animals. The development of transgenesis has created new directions in research and possibilities for its practical application. Generating transgenic animal species is not only aimed towards accelerating traditional breeding programs and improving animal health and the quality of animal products for consumption but can also be used in biomedicine. Animal studies are conducted to develop models used in gene function and regulation research and the genetic determinants of certain human diseases. Another direction of research, described in this review, focuses on the use of transgenic animals as a source of high-quality biopharmaceuticals, such as recombinant proteins. The further aspect discussed is the use of genetically modified animals as a source of cells, tissues, and organs for transplantation into human recipients, i.e., xenotransplantation. Numerous studies have shown that the pig (Sus scrofa domestica) is the most suitable species both as a research model for human diseases and as an optimal organ donor for xenotransplantation. Short pregnancy, short generation interval, and high litter size make the production of transgenic pigs less time-consuming in comparison with other livestock species This review describes genetically modified pigs used for biomedical research and the future challenges and perspectives for the use of the swine animal models.
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Affiliation(s)
- Magdalena Hryhorowicz
- Department of Biochemistry and Biotechnology, Poznan University of Life Sciences, Dojazd 11, 60-632 Poznań, Poland; (D.L.); (A.N.-T.); (N.R.); (J.Z.)
- Correspondence:
| | - Daniel Lipiński
- Department of Biochemistry and Biotechnology, Poznan University of Life Sciences, Dojazd 11, 60-632 Poznań, Poland; (D.L.); (A.N.-T.); (N.R.); (J.Z.)
| | - Szymon Hryhorowicz
- Institute of Human Genetics, Polish Academy of Sciences, Strzeszyńska 32, 60-479 Poznań, Poland;
| | - Agnieszka Nowak-Terpiłowska
- Department of Biochemistry and Biotechnology, Poznan University of Life Sciences, Dojazd 11, 60-632 Poznań, Poland; (D.L.); (A.N.-T.); (N.R.); (J.Z.)
| | - Natalia Ryczek
- Department of Biochemistry and Biotechnology, Poznan University of Life Sciences, Dojazd 11, 60-632 Poznań, Poland; (D.L.); (A.N.-T.); (N.R.); (J.Z.)
| | - Joanna Zeyland
- Department of Biochemistry and Biotechnology, Poznan University of Life Sciences, Dojazd 11, 60-632 Poznań, Poland; (D.L.); (A.N.-T.); (N.R.); (J.Z.)
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Lu T, Yang B, Wang R, Qin C. Xenotransplantation: Current Status in Preclinical Research. Front Immunol 2020; 10:3060. [PMID: 32038617 PMCID: PMC6989439 DOI: 10.3389/fimmu.2019.03060] [Citation(s) in RCA: 116] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 12/16/2019] [Indexed: 12/13/2022] Open
Abstract
The increasing life expectancy of humans has led to a growing numbers of patients with chronic diseases and end-stage organ failure. Transplantation is an effective approach for the treatment of end-stage organ failure; however, the imbalance between organ supply and the demand for human organs is a bottleneck for clinical transplantation. Therefore, xenotransplantation might be a promising alternative approach to bridge the gap between the supply and demand of organs, tissues, and cells; however, immunological barriers are limiting factors in clinical xenotransplantation. Thanks to advances in gene-editing tools and immunosuppressive therapy as well as the prolonged xenograft survival time in pig-to-non-human primate models, clinical xenotransplantation has become more viable. In this review, we focus on the evolution and current status of xenotransplantation research, including our current understanding of the immunological mechanisms involved in xenograft rejection, genetically modified pigs used for xenotransplantation, and progress that has been made in developing pig-to-pig-to-non-human primate models. Three main types of rejection can occur after xenotransplantation, which we discuss in detail: (1) hyperacute xenograft rejection, (2) acute humoral xenograft rejection, and (3) acute cellular rejection. Furthermore, in studies on immunological rejection, genetically modified pigs have been generated to bridge cross-species molecular incompatibilities; in the last decade, most advances made in the field of xenotransplantation have resulted from the production of genetically engineered pigs; accordingly, we summarize the genetically modified pigs that are currently available for xenotransplantation. Next, we summarize the longest survival time of solid organs in preclinical models in recent years, including heart, liver, kidney, and lung xenotransplantation. Overall, we conclude that recent achievements and the accumulation of experience in xenotransplantation mean that the first-in-human clinical trial could be possible in the near future. Furthermore, we hope that xenotransplantation and various approaches will be able to collectively solve the problem of human organ shortage.
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Affiliation(s)
- Tianyu Lu
- Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing, China.,NHC Key Laboratory of Human Disease Comparative Medicine, The Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.,Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, Beijing, China
| | - Bochao Yang
- Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing, China.,NHC Key Laboratory of Human Disease Comparative Medicine, The Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.,Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, Beijing, China
| | - Ruolin Wang
- Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing, China.,NHC Key Laboratory of Human Disease Comparative Medicine, The Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.,Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, Beijing, China
| | - Chuan Qin
- Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing, China.,NHC Key Laboratory of Human Disease Comparative Medicine, The Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.,Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, Beijing, China
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Carter MC, Akin C, Castells MC, Scott EP, Lieberman P. Idiopathic anaphylaxis yardstick: Practical recommendations for clinical practice. Ann Allergy Asthma Immunol 2019; 124:16-27. [PMID: 31513910 DOI: 10.1016/j.anai.2019.08.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 08/20/2019] [Accepted: 08/27/2019] [Indexed: 12/18/2022]
Abstract
Anaphylaxis is considered idiopathic when there is no known trigger. The signs and symptoms of idiopathic anaphylaxis (IA) are identical to those of anaphylaxis because of a known cause and can include cutaneous, circulatory, respiratory, gastrointestinal, and neurologic symptoms. Idiopathic anaphylaxis can be a frustrating disease for patients and health care providers. Episodes are unpredictable, and differential diagnosis is challenging. Current anaphylaxis guidelines have little specific guidance regarding differential diagnosis and long-term management of IA. Therefore, the objective of the Idiopathic Anaphylaxis Yardstick is to use published data and the authors' combined clinical experience to provide practical recommendations for the diagnosis and management of patients with IA.
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Affiliation(s)
| | - Cem Akin
- Department of Medicine, University of Michigan, Ann Arbor, Michigan
| | - Mariana C Castells
- Department of Medicine, Division of Rheumatology, Immunology, and Allergy, Mastocytosis Center, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | | | - Phil Lieberman
- Departments of Medicine and Pediatrics, Divisions of Allergy and Immunology, University of Tennessee, Memphis, Tennessee.
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Galili U. Evolution in primates by “Catastrophic‐selection” interplay between enveloped virus epidemics, mutated genes of enzymes synthesizing carbohydrate antigens, and natural anti‐carbohydrate antibodies. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 168:352-363. [DOI: 10.1002/ajpa.23745] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 10/09/2018] [Accepted: 10/16/2018] [Indexed: 02/01/2023]
Affiliation(s)
- Uri Galili
- Department of MedicineRush Medical College Chicago Illinois
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10
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Porcine to Human Heart Transplantation: Is Clinical Application Now Appropriate? J Immunol Res 2017; 2017:2534653. [PMID: 29238731 PMCID: PMC5697125 DOI: 10.1155/2017/2534653] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 10/08/2017] [Indexed: 11/24/2022] Open
Abstract
Cardiac xenotransplantation (CXTx) is a promising solution to the chronic shortage of donor hearts. Recent advancements in immune suppression have greatly improved the survival of heterotopic CXTx, now extended beyond 2 years, and life-supporting kidney XTx. Advances in donor genetic modification (B4GALNT2 and CMAH mutations) with proven Gal-deficient donors expressing human complement regulatory protein(s) have also accelerated, reducing donor pig organ antigenicity. These advances can now be combined and tested in life-supporting orthotopic preclinical studies in nonhuman primates and immunologically appropriate models confirming their efficacy and safety for a clinical CXTx program. Preclinical studies should also allow for organ rejection to develop xenospecific assays and therapies to reverse rejection. The complexity of future clinical CXTx presents a substantial and unique set of regulatory challenges which must be addressed to avoid delay; however, dependent on these prospective life-supporting preclinical studies in NHPs, it appears that the scientific path forward is well defined and the era of clinical CXTx is approaching.
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Galili U. α-Gal Nanoparticles in Wound and Burn Healing Acceleration. Adv Wound Care (New Rochelle) 2017; 6:81-92. [PMID: 28289553 PMCID: PMC5346952 DOI: 10.1089/wound.2016.0703] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 10/02/2016] [Indexed: 12/26/2022] Open
Abstract
Significance: Rapid recruitment and activation of macrophages may accelerate wound healing. Such accelerated healing was observed in wounds and burns of experimental animals treated with α-gal nanoparticles. Recent Advances: α-Gal nanoparticles present multiple α-gal epitopes (Galα1-3Galβ1-4GlcNAc-R). α-Gal nanoparticles applied to wounds bind anti-Gal (the most abundant antibody in humans) and generate chemotactic complement peptides, which rapidly recruit macrophages. Fc/Fc receptor interaction between anti-Gal coating the α-gal nanoparticles and recruited macrophages activates macrophages to produce cytokines that accelerate healing. α-Gal nanoparticles applied to burns and wounds in mice and pigs producing anti-Gal, decreased healing time by 40-60%. In mice, this accelerated healing avoided scar formation. α-Gal nanoparticle-treated wounds, in diabetic mice producing anti-Gal, healed within 12 days, whereas saline-treated wounds became chronic wounds. α-Gal nanoparticles are stable for years and may be applied dried, in suspension, aerosol, ointments, or within biodegradable materials. Critical Issues: α-Gal nanoparticle therapy can be evaluated only in mammalian models producing anti-Gal, including α1,3-galactosyltransferase knockout mice and pigs or Old World primates. Traditional experimental animal models synthesize α-gal epitopes and lack anti-Gal. Future Directions: Since anti-Gal is naturally produced in all humans, it is of interest to determine safety and efficacy of α-gal nanoparticles in accelerating wound and burn healing in healthy individuals and in patients with impaired wound healing such as diabetic patients and elderly individuals. In addition, efficacy of α-gal nanoparticle therapy should be studied in healing and regeneration of internal injuries such as surgical incisions, ischemic myocardium following myocardial infarction, and injured nerves.
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Affiliation(s)
- Uri Galili
- Correspondence: 910 South Michigan Avenue, Apartment 1404, Chicago, IL 60605(e-mail: )
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12
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Cooper DKC. Modifying the sugar icing on the transplantation cake. Glycobiology 2016; 26:571-81. [PMID: 26935763 DOI: 10.1093/glycob/cww028] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 02/25/2016] [Indexed: 12/13/2022] Open
Abstract
As a transplant surgeon, my interest in glycobiology began through my research into ABO-incompatible allotransplantation, and grew when my goal became overcoming the shortage of organs from deceased human donors by the transplantation of pig organs into patients with terminal organ failure (xenotransplantation/cross-species transplantation). The major target for human "natural" (preformed) anti-pig antibodies is galactose-α(1,3)-galactose (the "Gal" epitope), which is expressed on many pig cells, including the vascular endothelium. The binding of human IgM and IgG antibodies to Gal antigens initiates the process of hyperacute rejection, resulting in destruction of the pig graft within minutes or hours. This major barrier has been overcome by the production of pigs in which the gene for the enzyme α(1,3)-galactosyltransferase (GT) has been deleted by genetic engineering, resulting in GT knockout (GTKO) pigs. The two other known carbohydrate antigenic targets on pig cells for human anti-pig antibodies are (i) the product of the cytidine monophosphate-N-acetylneuraminic acid hydroxylase (CMAH) gene, i.e., N-glycolylneuraminic acid, and (ii) the product of the β1,4 N-acetylgalactosaminyltransferase gene, i.e., the Sd(a) antigen. Expression of these two has also been deleted in pigs. These genetic manipulations, together with others directed to overcoming primate complement and coagulation activation (the latter of which also relates to glycobiology) have contributed to the prolongation of pig graft survival in nonhuman primate recipients to many months rather than a few minutes. Clinical trials of the transplantation of pig cells are already underway and transplantation of pig organs may be expected within the relatively near future.
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Affiliation(s)
- David K C Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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Cooper DKC, Ezzelarab MB, Hara H, Iwase H, Lee W, Wijkstrom M, Bottino R. The pathobiology of pig-to-primate xenotransplantation: a historical review. Xenotransplantation 2016; 23:83-105. [PMID: 26813438 DOI: 10.1111/xen.12219] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 12/22/2015] [Indexed: 12/16/2022]
Abstract
The immunologic barriers to successful xenotransplantation are related to the presence of natural anti-pig antibodies in humans and non-human primates that bind to antigens expressed on the transplanted pig organ (the most important of which is galactose-α1,3-galactose [Gal]), and activate the complement cascade, which results in rapid destruction of the graft, a process known as hyperacute rejection. High levels of elicited anti-pig IgG may develop if the adaptive immune response is not prevented by adequate immunosuppressive therapy, resulting in activation and injury of the vascular endothelium. The transplantation of organs and cells from pigs that do not express the important Gal antigen (α1,3-galactosyltransferase gene-knockout [GTKO] pigs) and express one or more human complement-regulatory proteins (hCRP, e.g., CD46, CD55), when combined with an effective costimulation blockade-based immunosuppressive regimen, prevents early antibody-mediated and cellular rejection. However, low levels of anti-non-Gal antibody and innate immune cells and/or platelets may initiate the development of a thrombotic microangiopathy in the graft that may be associated with a consumptive coagulopathy in the recipient. This pathogenic process is accentuated by the dysregulation of the coagulation-anticoagulation systems between pigs and primates. The expression in GTKO/hCRP pigs of a human coagulation-regulatory protein, for example, thrombomodulin, is increasingly being associated with prolonged pig graft survival in non-human primates. Initial clinical trials of islet and corneal xenotransplantation are already underway, and trials of pig kidney or heart transplantation are anticipated within the next few years.
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Affiliation(s)
- David K C Cooper
- The Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mohamed B Ezzelarab
- The Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Hidetaka Hara
- The Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Hayato Iwase
- The Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Whayoung Lee
- The Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Martin Wijkstrom
- The Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Rita Bottino
- Institute for Cellular Therapeutics, Allegheny-Singer Research Institute, Pittsburgh, PA, USA
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Cooper DKC, Ekser B, Tector AJ. Immunobiological barriers to xenotransplantation. Int J Surg 2015; 23:211-216. [PMID: 26159291 PMCID: PMC4684773 DOI: 10.1016/j.ijsu.2015.06.068] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 06/19/2015] [Indexed: 01/26/2023]
Abstract
Binding of natural anti-pig antibodies in humans and nonhuman primates to carbohydrate antigens expressed on the transplanted pig organ, the most important of which is galactose-α1,3-galactose (Gal), activate the complement cascade, which results in destruction of the graft within minutes or hours, known as hyperacute rejection. Even if antibody is removed from the recipient's blood by plasmapheresis, recovery of antibody is associated with acute humoral xenograft rejection. If immunosuppressive therapy is inadequate, the development of high levels of T cell-dependent elicited anti-pig IgG similarly results in graft destruction, though classical acute cellular rejection is rarely seen. Vascular endothelial activation by low levels of anti-nonGal antibody, coupled with dysregulation of the coagulation-anticoagulation systems between pigs and primates, leads to a thrombotic microangiopathy in the graft that may be associated with a consumptive coagulopathy in the recipient. The most successful approach to overcoming these barriers is by genetically-engineering the pig to provide it with resistance to the human humoral and cellular immune responses and to correct the coagulation discrepancies between the two species. Organs and cells from pigs that (i) do not express the important Gal antigen, (ii) express a human complement-regulatory protein, and (iii) express a human coagulation-regulatory protein, when combined with an effective immunosuppressive regimen, have been associated with prolonged pig graft survival in nonhuman primates.
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Affiliation(s)
- David K C Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Burcin Ekser
- Transplant Division, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - A Joseph Tector
- Transplant Division, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
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Galili U. Avoiding Detrimental Human Immune Response Against Mammalian Extracellular Matrix Implants. TISSUE ENGINEERING PART B-REVIEWS 2015; 21:231-41. [DOI: 10.1089/ten.teb.2014.0392] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Uri Galili
- Department of Surgery, University of Massachusetts Medical School, Worcester, Massachusetts
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Acceleration of wound healing by α-gal nanoparticles interacting with the natural anti-Gal antibody. J Immunol Res 2015; 2015:589648. [PMID: 25922849 PMCID: PMC4397477 DOI: 10.1155/2015/589648] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 03/18/2015] [Indexed: 12/16/2022] Open
Abstract
Application of α-gal nanoparticles to wounds and burns induces accelerated healing by harnessing the natural anti-Gal antibody which constitutes ~1% of human immunoglobulins. α-gal nanoparticles present multiple α-gal epitopes (Galα1-3Galβ1-4GlcNAc-R), the carbohydrate ligand of anti-Gal. Studied α-gal nanoparticles were comprised of glycolipids with α-gal epitopes, phospholipids, and cholesterol. Binding of anti-Gal to α-gal nanoparticles in wounds activates the complement cascade, resulting in formation of chemotactic complement cleavage peptides that induce rapid recruitment of many macrophages. The Fc/Fcγ receptors interaction between anti-Gal coating α-gal nanoparticles and the recruited macrophages activates macrophages to produce cytokines/growth factors that promote wound healing and recruit stem cells. Studies of wound healing by α-gal nanoparticles were feasible in α1,3galactosyltransferase knockout mice and pigs. In contrast to other nonprimate mammals, these mice and pigs lack the α-gal epitope, and thus they are not immunotolerant to it and produce anti-Gal. Treatment of skin wounds and burns with α-gal nanoparticles resulted in 40-60% decrease in healing time in comparison with control wounds treated with saline. This accelerated healing is associated with increased recruitment of macrophages and extensive angiogenesis in wounds, faster regrowth of epidermis, and regeneration of the dermis. The accelerated healing further decreases and may completely eliminate fibrosis and scar formation in wounds. Since healing of internal injuries is mediated by mechanisms similar to those in external wound healing, it is suggested that α-gal nanoparticles treatment may also improve regeneration and restoration of biological function following internal injuries such as surgical incisions, myocardial ischemia following infarction, and nerve injuries.
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Significance of the evolutionary α1,3-galactosyltransferase (GGTA1) gene inactivation in preventing extinction of apes and old world monkeys. J Mol Evol 2014; 80:1-9. [PMID: 25315716 DOI: 10.1007/s00239-014-9652-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Accepted: 10/06/2014] [Indexed: 10/24/2022]
Abstract
The α1,3-galactosyltransferase (α1,3GT or GGTA1) gene displays unique evolutionary characteristics. This gene appeared early in mammalian evolution and is absent in other vertebrates. The α1,3GT gene is active in marsupials, nonprimate placental mammals, lemurs (prosimians) and New World monkeys, encoding the α1,3GT enzyme that synthesizes a carbohydrate antigen called "α-gal epitope." The α-gal epitope is present in large numbers on cell membrane glycolipids and glycoproteins. The α1,3GT gene was inactivated in ancestral Old World monkeys and apes by frameshift single-base deletions forming premature stop codons. Because of this gene inactivation, humans, apes, and Old World monkeys lack α-gal epitopes and naturally produce an antibody called the "anti-Gal antibody" which binds specifically to α-gal epitopes and which is the most abundant antibody in humans. The evolutionary event that resulted in the inactivation of the α1,3GT gene in ancestral Old World primates could have been mediated by a pathogen endemic to Eurasia-Africa landmass that exerted pressure for selection of primate populations lacking the α-gal epitope. Once the α-gal epitope was eliminated, primates could produce the anti-Gal antibody, possibly as means of defense against pathogens expressing this epitope. This assumption is supported by the fossil record demonstrating an almost complete extinction of apes in the late Miocene and failure of Old World monkeys to radiate into multiple species before that period. A present outcome of this evolutionary event is the anti-Gal-mediated rejection of mammalian xenografts expressing α-gal epitopes in humans, apes, and Old World monkeys.
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Byrne GW, Du Z, Stalboerger P, Kogelberg H, McGregor CGA. Cloning and expression of porcine β1,4 N-acetylgalactosaminyl transferase encoding a new xenoreactive antigen. Xenotransplantation 2014; 21:543-54. [PMID: 25176027 PMCID: PMC4262693 DOI: 10.1111/xen.12124] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 05/28/2014] [Indexed: 01/03/2023]
Abstract
Background Xenograft rejection of pigs organs with an engineered mutation in the GGTA-1 gene (GTKO) remains a predominantly antibody mediated process which is directed to a variety of non-Gal protein and carbohydrate antigens. We previously used an expression library screening strategy to identify six porcine endothelial cell cDNAs which encode pig antigens that bind to IgG induced after pig-to-primate cardiac xenotransplantation. One of these gene products was a glycosyltransferase with homology to the bovine β1,4 N-acetylgalactosaminyltransferase (B4GALNT2). We now characterize the porcine B4GALNT2 gene sequence, genomic organization, expression, and functional significance. Methods The porcine B4GALNT2 cDNA was recovered from the original library isolate, subcloned, sequenced, and used to identify a bacterial artificial chromosome (BAC) containing the entire B4GALNT2 locus from the Children's Hospital Oakland Research Institute BACPAC Resource Centre (#AC173453). PCR primers were designed to map the intron/exon genomic organization in the BAC clone. A stable human embryonic kidney (HEK) cell line expressing porcine B4GALNT2 (HEK-B4T) was produced. Expression of porcine B4GALNT2 in HEK-B4T cells was characterized by immune staining and siRNA transfection. The effects of B4GALNT2 expression in HEK-B4T cells was measured by flow cytometry and complement mediated lysis. Antibody binding to HEK and HEK-B4T cells was used to detect an induced antibody response to the B4GALNT2 produced glycan and the results were compared to GTKO PAEC specific non-Gal antibody induction. Expression of porcine B4GALNT2 in pig cells and tissues was measured by qualitative and quantitative real time reverse transcriptase PCR and by Dolichos biflorus agglutinin (DBA) tissue staining. Results The porcine B4GALNT2 gene shares a conserved genomic organization and encodes an open reading frame with 76 and 70% amino acid identity to the human and murine B4GALNT2 genes, respectively. The B4GALNT2 gene is expressed in porcine endothelial cells and shows a broadly distributed expression pattern. Expression of porcine B4GALNT2 in human HEK cells (HEK-B4T) results in increased binding of antibody to the B4GALNT2 enzyme, and increased reactivity with anti-Sda and DBA. HEK-B4T cells show increased sensitivity to complement mediated lysis when challenged with serum from primates after pig to primate cardiac xenotransplantation. In GTKO and GTKO:CD55 cardiac xenotransplantation recipients there is a significant correlation between the induction of a non-Gal antibody, measured using GTKO PAECs, and the induction of antibodies which preferentially bind to HEK-B4T cells. Conclusion The functional isolation of the porcine B4GALNT2 gene from a PAEC expression library, the pattern of B4GALNT2 gene expression and its sensitization of HEK-B4T cells to antibody binding and complement mediated lysis indicates that the enzymatic activity of porcine B4GALNT2 produces a new immunogenic non-Gal glycan which contributes in part to the non-Gal immune response detected after pig-to-baboon cardiac xenotransplantation.
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Affiliation(s)
- Guerard W Byrne
- Department of Surgery, Mayo Clinic, Rochester, MN, USA; Institute of Cardiovascular Science, University College London, London, UK
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Cooper DKC, Satyananda V, Ekser B, van der Windt DJ, Hara H, Ezzelarab MB, Schuurman HJ. Progress in pig-to-non-human primate transplantation models (1998-2013): a comprehensive review of the literature. Xenotransplantation 2014; 21:397-419. [PMID: 25176336 DOI: 10.1111/xen.12127] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 06/03/2014] [Indexed: 12/11/2022]
Abstract
BACKGROUND The pig-to-non-human primate model is the standard choice for in vivo studies of organ and cell xenotransplantation. In 1998, Lambrigts and his colleagues surveyed the entire world literature and reported all experimental studies in this model. With the increasing number of genetically engineered pigs that have become available during the past few years, this model is being utilized ever more frequently. METHODS We have now reviewed the literature again and have compiled the data we have been able to find for the period January 1, 1998 to December 31, 2013, a period of 16 yr. RESULTS The data are presented for transplants of the heart (heterotopic and orthotopic), kidney, liver, lung, islets, neuronal cells, hepatocytes, corneas, artery patches, and skin. Heart, kidney, and, particularly, islet xenograft survival have increased significantly since 1998. DISCUSSION The reasons for this are briefly discussed. A comment on the limitations of the model has been made, particularly with regard to those that will affect progression of xenotransplantation toward the clinic.
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Affiliation(s)
- David K C Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
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20
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Therapeutic Strategies for Xenotransplantation. Xenotransplantation 2014. [DOI: 10.1128/9781555818043.ch6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Iwase H, Ezzelarab MB, Ekser B, Cooper DKC. The role of platelets in coagulation dysfunction in xenotransplantation, and therapeutic options. Xenotransplantation 2014; 21:201-20. [PMID: 24571124 DOI: 10.1111/xen.12085] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 01/08/2014] [Indexed: 12/11/2022]
Abstract
Xenotransplantation could resolve the increasing discrepancy between the availability of deceased human donor organs and the demand for transplantation. Most advances in this field have resulted from the introduction of genetically engineered pigs, e.g., α1,3-galactosyltransferase gene-knockout (GTKO) pigs transgenic for one or more human complement-regulatory proteins (e.g., CD55, CD46, CD59). Failure of these grafts has not been associated with the classical features of acute humoral xenograft rejection, but with the development of thrombotic microangiopathy in the graft and/or consumptive coagulopathy in the recipient. Although the precise mechanisms of coagulation dysregulation remain unclear, molecular incompatibilities between primate coagulation factors and pig natural anticoagulants exacerbate the thrombotic state within the xenograft vasculature. Platelets play a crucial role in thrombosis and contribute to the coagulation disorder in xenotransplantation. They are therefore important targets if this barrier is to be overcome. Further genetic manipulation of the organ-source pigs, such as pigs that express one or more coagulation-regulatory genes (e.g., thrombomodulin, endothelial protein C receptor, tissue factor pathway inhibitor, CD39), is anticipated to inhibit platelet activation and the generation of thrombus. In addition, adjunctive pharmacologic anti-platelet therapy may be required. The genetic manipulations that are currently being tested are reviewed, as are the potential pharmacologic agents that may prove beneficial.
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Affiliation(s)
- Hayato Iwase
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
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Holgersson J, Rydberg L, Breimer ME. Molecular deciphering of the ABO system as a basis for novel diagnostics and therapeutics in ABO incompatible transplantation. Int Rev Immunol 2013; 33:174-94. [PMID: 24350817 DOI: 10.3109/08830185.2013.857408] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
In recent years ABO incompatible kidney transplantation (KTx) has become a more or less clinical routine procedure with graft and patient survival similar to those of ABO compatible transplants. Antigen-specific immunoadsorption (IA) for anti-A and anti-B antibody removal constitutes in many centers an important part of the treatment protocol. ABO antibody titration by hemagglutination is guiding the treatment; both if the recipient can be transplanted as well as in cases of suspected rejections if antibody removal should be performed. Despite the overall success of ABO incompatible KTx, there is still room for improvements and an extension of the technology to include other solid organs. Based on an increased understanding of the structural complexity and tissue distribution of ABH antigens and the fine epitope specificity of the ABO antibody repertoire, improved IA matrices and ABO antibody diagnostics should be developed. Furthermore, understanding the molecular mechanisms behind accommodation of ABO incompatible renal allografts could make it possible to induce long-term allograft acceptance also in human leukocyte antigen (HLA) sensitized recipients and, perhaps, also make clinical xenotransplantation possible.
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Affiliation(s)
- Jan Holgersson
- 1Department of Clinical Chemistry and Transfusion Medicine and
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Kennedy JL, Stallings AP, Platts-Mills TA, Oliveira WM, Workman L, James HR, Tripathi A, Lane CJ, Matos L, Heymann PW, Commins SP. Galactose-α-1,3-galactose and delayed anaphylaxis, angioedema, and urticaria in children. Pediatrics 2013; 131:e1545-52. [PMID: 23569097 PMCID: PMC3639458 DOI: 10.1542/peds.2012-2585] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND AND OBJECTIVE Despite a thorough history and comprehensive testing, many children who present with recurrent symptoms consistent with allergic reactions elude diagnosis. Recent research has identified a novel cause for "idiopathic" allergic reactions; immunoglobulin E (IgE) antibody specific for the carbohydrate galactose-α-1,3-galactose (α-Gal) has been associated with delayed urticaria and anaphylaxis that occurs 3 to 6 hours after eating beef, pork, or lamb. We sought to determine whether IgE antibody to α-Gal was present in sera of pediatric patients who reported idiopathic anaphylaxis or urticaria. METHODS Patients aged 4 to 17 were enrolled in an institutional review board-approved protocol at the University of Virginia and private practice allergy offices in Lynchburg, VA. Sera was obtained and analyzed by ImmunoCAP for total IgE and specific IgE to α-Gal, beef, pork, cat epithelium and dander, Fel d 1, dog dander, and milk. RESULTS Forty-five pediatric patients were identified who had both clinical histories supporting delayed anaphylaxis or urticaria to mammalian meat and IgE antibody specific for α-Gal. In addition, most of these cases had a history of tick bites within the past year, which itched and persisted. CONCLUSIONS A novel form of anaphylaxis and urticaria that occurs 3 to 6 hours after eating mammalian meat is not uncommon among children in our area. Identification of these cases may not be straightforward and diagnosis is best confirmed by specific testing, which should certainly be considered for children living in the area where the Lone Star tick is common.
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Affiliation(s)
- Joshua L. Kennedy
- Division of Allergy and Immunology, Department of Internal Medicine and
| | - Amy P. Stallings
- Division of Allergy and Immunology, Department of Internal Medicine and
| | | | | | - Lisa Workman
- Division of Allergy and Immunology, Department of Internal Medicine and
| | - Haley R. James
- Division of Allergy and Immunology, Department of Internal Medicine and
| | - Anubha Tripathi
- Division of Allergy and Immunology, Department of Internal Medicine and
| | | | - Luis Matos
- Asthma and Allergy Center of Lynchburg, Lynchburg, Virginia
| | - Peter W. Heymann
- Pediatrics, University of Virginia Health System, Charlottesville, Virginia
| | - Scott P. Commins
- Division of Allergy and Immunology, Department of Internal Medicine and,Pediatrics, University of Virginia Health System, Charlottesville, Virginia
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24
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Galili U. Discovery of the natural anti-Gal antibody and its past and future relevance to medicine. Xenotransplantation 2013; 20:138-47. [PMID: 23577774 DOI: 10.1111/xen.12034] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 03/15/2013] [Indexed: 12/11/2022]
Abstract
This is a personal account of the discovery of the natural anti-Gal antibody, the most abundant natural antibody in humans, the reciprocal distribution of this antibody and its ligand the α-gal epitope in mammals and the immunological barrier this antibody has formed in porcine to human xenotransplantation. This barrier has been overcome in the recent decade with the generation of α1,3-galactosyltransferase gene-knockout pigs. However, anti-Gal continues to be relevant in medicine as it can be harnessed for various therapeutic effects. Anti-Gal converts tumor lesions injected with α-gal glycolipids into vaccines that elicit a protective anti-tumor immune response by in situ targeting of tumor cells for uptake by antigen-presenting cells. This antibody further accelerates wound and burn healing by interaction with α-gal nanoparticles applied to injured areas and induction of rapid recruitment and activation of macrophages. Anti-Gal/α-gal nanoparticle immune complexes may further induce rapid recruitment and activation of macrophages in ischemic myocardium and injured nerves, thereby inducing tissue regeneration and prevention of fibrosis.
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Affiliation(s)
- Uri Galili
- Department of Surgery, University of Massachusetts Medical School, Worcester, MA, USA
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Hamsten C, Starkhammar M, Tran TAT, Johansson M, Bengtsson U, Ahlén G, Sällberg M, Grönlund H, van Hage M. Identification of galactose-α-1,3-galactose in the gastrointestinal tract of the tick Ixodes ricinus; possible relationship with red meat allergy. Allergy 2013; 68:549-52. [PMID: 23414348 DOI: 10.1111/all.12128] [Citation(s) in RCA: 147] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/02/2013] [Indexed: 11/28/2022]
Abstract
Patients with IgE antibodies against the carbohydrate epitope galactose-α-1,3-galactose (α-Gal) have reported severe allergic reactions after consumption of red meat. Investigations have revealed associations between IgE to α-Gal and tick bites. We provide the first direct evidence that α-Gal is present within ticks thus potentially explaining the relationship between tick exposure and sensitization to α-Gal, with development of red meat allergy as a secondary phenomena. Serum from Swedish patients with delayed severe reactions to red meat was included in the study. A dose-dependent inhibition of IgE responses to α-Gal by the tick Ixodes ricinus is demonstrated. Furthermore, using cryostat-cut sections of I. ricinus, we show that both a monoclonal and a polyclonal antibody against α-Gal stains the gastrointestinal tract of the tick. The same pattern is seen when staining with patient sera IgE positive to α-Gal. These results confirm that the α-Gal epitope is present in I. ricinus and imply host exposure to α-Gal during a tick bite. This provides further evidence that tick bites are associated with IgE responses to α-Gal and red meat allergy.
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Affiliation(s)
| | - M. Starkhammar
- Department of Internal Medicine; Södersjukhuset; Stockholm; Sweden
| | - T. A. T. Tran
- Department of Medicine Solna; Clinical Immunology and Allergy Unit; Karolinska Institutet and University Hospital Solna; Stockholm; Sweden
| | | | - U. Bengtsson
- Department of Internal Medicine; Södersjukhuset; Stockholm; Sweden
| | - G. Ahlén
- Division of Clinical Microbiology; Department of Laboratory Medicine; Karolinska Institutet and University Hospital Huddinge; Stockholm; Sweden
| | - M. Sällberg
- Division of Clinical Microbiology; Department of Laboratory Medicine; Karolinska Institutet and University Hospital Huddinge; Stockholm; Sweden
| | - H. Grönlund
- Department of Medicine Solna; Clinical Immunology and Allergy Unit; Karolinska Institutet and University Hospital Solna; Stockholm; Sweden
| | - M. van Hage
- Department of Medicine Solna; Clinical Immunology and Allergy Unit; Karolinska Institutet and University Hospital Solna; Stockholm; Sweden
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Shen Z, Ye W, Ten X. Suppression of NF-kappaB p65 expression attenuates delayed xenograft rejection. Xenotransplantation 2013; 20:123-30. [PMID: 23489828 DOI: 10.1111/xen.12027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 02/17/2013] [Indexed: 11/28/2022]
Abstract
BACKGROUND Delayed xenograft rejection (DXR) involves type II vascular endothelial cell (VEC) activation including upregulation of pro-inflammatory genes, which contributes to infiltration into the graft and a complex process of cytokine production. Approaches to prevent DXR have shown limited success. In this study, we modified heart donors using siRNA in an attempt to attenuate DXR and to improve xenograft survival in the mouse-to-rat heterotopic heart transplant model. METHODS siRNA technology was used to inhibit NF-kappaB p65 gene expression in vivo in mice. After the donor was transfected with siRNA, the effects of NF-kappaB siRNA on DXR and expression of NF-kappaB and pro-inflammatory genes were evaluated in a concordant mouse-to-rat cardiac xenograft model. RESULTS Treatment of NF-kappaB siRNA prolonged median heart graft survival time in the recipient rats from 1.7 days in a PBS control group to 5.4 days in the NF-kappaB siRNA-treated group (P < 0.05). Compared with normal mouse hearts, the NF-kappaB p65 mRNA relative levels following siRNA injection in the donors decreased significantly (approximately 70% reduction) in grafts harvested 12 h after transplantation. The mRNA levels of VCAM-1, ICAM-1, and interleukin-1 displayed a similar reduction. Histological evaluation using light and electron microscopy showed that damage of endothelial cells after NF-kappaB siRNA treament occured at a later time. CONCLUSION Transfection of NF-kappaB p65 siRNA in donor animals can delay the emergence of DXR. This treatment may be used as part of strategies to minimize the complex and multi-faceted rejection responses in vascularized xenografts.
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Affiliation(s)
- Zhenya Shen
- Department of Cardiovascular Surgery of the First affiliated Hospital, Institute for Cardiovascular Science of Soochow University, Suzhou, Jiangsu 215006, China.
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Jappe U. [Update on meat allergy. α-Gal: a new epitope, a new entity?]. DER HAUTARZT 2012; 63:299-306. [PMID: 22418768 DOI: 10.1007/s00105-011-2266-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The association between the carbohydrate galactose-[alpha]-1,3-galactose (α-Gal) and anaphylaxis was first documented after severe hypersensitivity reactions to cetuximab, a chimeric mouse-human IgG1 monoclonal antibody approved for targeted therapy of carcinomas of colon, as well as of the head and neck region. α-Gal is a ubiquitous glycan moiety expressed on cells and tissue of non-primate mammals. Since this epitope is not expressed in humans, it is very immunogenic for them. α-Gal is located on the Fab portion of cetuximab and thus on the murine part of the chimera. The anaphylactic reactions to the antibody were mediated by IgE specific for α-Gal. Anti-α-Gal-IgE were first detected in sera of patients from the southeastern U.S. and reacted with a wide range of mammalian allergens. The geographic distribution prompted investigations of sensitization routes apart from the ingestion of red meat, such as tick bites und parasitic infections. Anti-α-Gal-IgE seems to be of clinical relevance for allergy to red meat and for the pork-cat syndrome. It is also associated with a novel form of delayed anaphylaxis, which appears more than 3 hours following the ingestion of red meat (beef, pork and lamb), a phenomenon which is still to be elucidated. For most of these patients conventional skin prick tests with commercial reagents proved insufficient for diagnosis.
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Affiliation(s)
- U Jappe
- Klinik für Dermatologie, Allergologie und Venerologie, Universität Lübeck, Lübeck, Deutschland.
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Abstract
Anti-non gal antibodies are produced in xenograft recipients against multiple xenogeneic antigens. Studies in monkeys transplanted with pig organs lacking α-gal epitopes have suggested that anti-non gal antibodies mediate acute and chronic rejection of xenografts. This overview describes studies of these antibodies in patients who received xenografts and includes (1) an ovarian carcinoma patient receiving three intraperitoneal infusions of mouse fibroblasts in a gene therapy study, (2) orthopedic patients with torn anterior cruciate ligament replaced by a ligament made of pig patellar tendon, and (3) diabetic patients receiving fetal pig islet cell clusters xenograft together with a kidney allograft. Anti-non gal antibodies were found to be continuously produced as long as the xenograft was present in the recipient and were directed against a large number of pig proteins. Monitoring the immune response in the recipient of mouse fibroblasts indicated that the production of anti-non gal antibodies is much slower than that of the anti-Gal antibody, suggesting that they are generated by multiple B-cell clones, each initially comprising relatively few cells. Potent immunosuppression to prevent allograft rejection does not fully inhibit the production of anti-non gal antibodies. Much of this antibody response seems to be due to the differences in amino acid sequences between pig and human orthologous proteins as a result of evolutionary mutations. Overcoming the anti-non gal antibody barrier will require immunosuppressive agents that preferentially inhibit this immune response while maintaining protection against pathogens, or alternatively development of methods for induction of immune tolerance to xenogeneic pig antigens.
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Impaired allergy diagnostics among parasite-infected patients caused by IgE antibodies to the carbohydrate epitope galactose-α 1,3-galactose. J Allergy Clin Immunol 2011; 127:1024-8. [PMID: 21376382 DOI: 10.1016/j.jaci.2011.01.033] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 01/12/2011] [Accepted: 01/13/2011] [Indexed: 12/18/2022]
Abstract
BACKGROUND The carbohydrate epitope galactose-α 1,3-galactose (α-Gal) is abundantly expressed on nonprimate mammalian proteins. We have recently shown that α-Gal is responsible for the IgE binding to cat IgA, a newly identified cat allergen (Fel d 5). OBJECTIVE We sought to investigate the diagnostic relevance of IgE antibodies to Fel d 5 and α-Gal among parasite-infected patients from central Africa without cat allergy compared with patients with cat allergy from the same region. METHODS Sera from 47 parasite-infected patients and 31 patients with cat allergy were analyzed for total IgE and IgE antibodies against cat dander extract (CDE) by using the ImmunoCAP system. Inhibition assay was performed with α-Gal on solid phase-bound CDE. The presence of IgE specific for the major cat allergen Fel d 1, Fel d 5, and α-Gal was analyzed by means of ELISA. RESULTS Among the 47 parasite-infected patients, 85% had IgE antibodies against α-Gal (OD; median, 0.175; range, 0.102-1.466) and 66% against Fel d 5 (OD; median, 0.13; range, 0.103-1.285). Twenty-four of the parasite-infected patients were sensitized to CDE, and 21 of them had IgE antibodies to Fel d 5 and α-Gal. There was no correlation between IgE levels to CDE and rFel d 1 among the parasite-infected patients but a strong correlation between CDE and Fel d 5 and α-Gal (P < .001). Among the group with cat allergy, only 5 patients had IgE to α-Gal, and nearly 75% (n = 23) had IgE to rFel d 1 (median, 7.07 kU(A)/L; range, 0.51-148.5 kU(A)/L). In contrast, among the patients with cat allergy, there was a correlation between IgE levels to CDE and rFel d 1 (P < .05) but no correlation between CDE and Fel d 5 and α-Gal. CONCLUSION IgE to α-Gal causes impaired allergy diagnostics in parasite-infected patients. Screening for IgE to rFel d 1 and other allergens without carbohydrates might identify patients with true cat sensitization/allergy in parasite-infested areas.
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Ekser B, Cooper DKC. Overcoming the barriers to xenotransplantation: prospects for the future. Expert Rev Clin Immunol 2010; 6:219-30. [PMID: 20402385 PMCID: PMC2857338 DOI: 10.1586/eci.09.81] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cross-species transplantation (xenotransplantation) has immense potential to solve the critical need for organs, tissues and cells for clinical transplantation. The increasing availability of genetically engineered pigs is enabling progress to be made in pig-to-nonhuman primate experimental models. Potent pharmacologic immunosuppressive regimens have largely prevented T-cell rejection and a T-cell-dependent elicited antibody response. However, coagulation dysfunction between the pig and primate is proving to be a major problem, and this can result in life-threatening consumptive coagulopathy. This complication is unlikely to be overcome until pigs expressing a human 'antithrombotic' or 'anticoagulant' gene, such as thrombomodulin, tissue factor pathway inhibitor or CD39, become available. Progress in islet xenotransplantation has been more encouraging, and diabetes has been controlled in nonhuman primates for periods in excess of 6 months, although this has usually been achieved using immunosuppressive protocols that might not be clinically applicable. Further advances are required to overcome the remaining barriers.
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Affiliation(s)
- Burcin Ekser
- Thomas E Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA, USA, and Department of Surgery and Organ Transplantation, University of Padua, Padua, Italy
| | - David KC Cooper
- Thomas E Starzl Transplantation Institute, University of Pittsburgh Medical Center, Starzl Biomedical Science Tower, W1543, 200 Lothrop Street, Pittsburgh, PA 15261, USA, Tel.: +1 412 383 6961, Fax: +1 412 624 1172,
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Commins SP, Satinover SM, Hosen J, Mozena J, Borish L, Lewis BD, Woodfolk JA, Platts-Mills TAE. Delayed anaphylaxis, angioedema, or urticaria after consumption of red meat in patients with IgE antibodies specific for galactose-alpha-1,3-galactose. J Allergy Clin Immunol 2009; 123:426-33. [PMID: 19070355 PMCID: PMC3324851 DOI: 10.1016/j.jaci.2008.10.052] [Citation(s) in RCA: 459] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Revised: 09/26/2008] [Accepted: 10/28/2008] [Indexed: 02/06/2023]
Abstract
BACKGROUND Carbohydrate moieties are frequently encountered in food and can elicit IgE responses, the clinical significance of which has been unclear. Recent work, however, has shown that IgE antibodies to galactose-alpha-1,3-galactose (alpha-gal), a carbohydrate commonly expressed on nonprimate mammalian proteins, are capable of eliciting serious, even fatal, reactions. OBJECTIVE We sought to determine whether IgE antibodies to alpha-gal are present in sera from patients who report anaphylaxis or urticaria after eating beef, pork, or lamb. METHODS Detailed histories were taken from patients presenting to the University of Virginia Allergy Clinic. Skin prick tests (SPTs), intradermal skin tests, and serum IgE antibody analysis were performed for common indoor, outdoor, and food allergens. RESULTS Twenty-four patients with IgE antibodies to alpha-gal were identified. These patients described a similar history of anaphylaxis or urticaria 3 to 6 hours after the ingestion of meat and reported fewer or no episodes when following an avoidance diet. SPTs to mammalian meat produced wheals of usually less than 4 mm, whereas intradermal or fresh-food SPTs provided larger and more consistent wheal responses. CAP-RAST testing revealed specific IgE antibodies to beef, pork, lamb, cow's milk, cat, and dog but not turkey, chicken, or fish. Absorption experiments indicated that this pattern of sensitivity was explained by an IgE antibody specific for alpha-gal. CONCLUSION We report a novel and severe food allergy related to IgE antibodies to the carbohydrate epitope alpha-gal. These patients experience delayed symptoms of anaphylaxis, angioedema, or urticaria associated with eating beef, pork, or lamb.
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Affiliation(s)
- Scott P. Commins
- Asthma and Allergic Diseases Center, University of Virginia Health System, Charlottesville
| | - Shama M. Satinover
- Asthma and Allergic Diseases Center, University of Virginia Health System, Charlottesville
| | - Jacob Hosen
- Asthma and Allergic Diseases Center, University of Virginia Health System, Charlottesville
| | | | - Larry Borish
- Asthma and Allergic Diseases Center, University of Virginia Health System, Charlottesville
| | | | - Judith A. Woodfolk
- Asthma and Allergic Diseases Center, University of Virginia Health System, Charlottesville
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Honorary Membership of International Xenotransplantation Association Conferred Upon Professor Ian F C McKenzie (September 18, 2007). Xenotransplantation 2008; 15:285-9. [DOI: 10.1111/j.1399-3089.2008.00491.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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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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Cooper DK. Frankenswine, or bringing home the bacon: How close are we to clinical trials in xenotransplantation? Organogenesis 2008; 4:1-10. [PMID: 19279708 DOI: 10.4161/org.5383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Accepted: 01/31/2008] [Indexed: 11/19/2022] Open
Abstract
Xenotransplantation-specifically from pig into human-could resolve the critical shortage of organs, tissues and cells for clinical transplantation. Genetic engineering techniques in pigs are relatively well-developed and to date have largely been aimed at producing pigs that either (1) express high levels of one or more human complement-regulatory protein(s), such as decay-accelerating factor or membrane cofactor protein, or (2) have deletion of the gene responsible for the expression of the oligosaccharide, Galalpha1,3Gal (Gal), the major target for human anti-pig antibodies, or (3) have both manipulations. Currently the transplantation of pig organs in adequately-immunosuppressed baboons results in graft function for periods of 2-6 months (auxiliary hearts) and 2-3 months (life-supporting kidneys). Pig islets have maintained normoglycemia in diabetic monkeys for >6 months. The remaining immunologic barriers to successful xenotransplantation are discussed, and brief reviews made of (1) the potential risk of the transmission of an infectious microorganism from pig to patient and possibly to the public at large, (2) the potential physiologic incompatibilities between a pig organ and its human counterpart, (3) the major ethical considerations of clinical xenotransplantation, and (4) the possible alternatives that compete with xenotransplantation in the field of organ or cell replacement, such as mechanical devices, tissue engineering, stem cell biology and organogenesis. Finally, the proximity of clinical trials is discussed. Islet xenotransplantation is already at the stage where clinical trials are actively being considered, but the transplantation of pig organs will probably require further genetic modifications to be made to the organ-source pigs to protect their tissues from the coagulation/anticoagulation dysfunction that plays a significant role in pig graft failure after transplantation in primates.
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Affiliation(s)
- David Kc Cooper
- Thomas E. Starzl Transplantation Institute; Department of Surgery; University of Pittsburgh; Pittsburgh, Pennsylvania USA
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The Galalpha1,3Galbeta1,4GlcNAc-R (alpha-Gal) epitope: a carbohydrate of unique evolution and clinical relevance. Biochim Biophys Acta Gen Subj 2007; 1780:75-88. [PMID: 18047841 DOI: 10.1016/j.bbagen.2007.11.003] [Citation(s) in RCA: 307] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Revised: 11/10/2007] [Accepted: 11/13/2007] [Indexed: 11/22/2022]
Abstract
In 1985, we reported that a naturally occurring human antibody (anti-Gal), produced as the most abundant antibody (1% of immunoglobulins) throughout the life of all individuals, recognizes a carbohydrate epitope Galalpha1-3Galbeta1-4GlcNAc-R (the alpha-gal epitope). Since that time, an extensive literature has developed on discoveries related to the alpha-gal epitope and the anti-Gal antibody, including the barrier they form in xenotransplantation and their reciprocity in mammalian evolution. This review covers these topics and new avenues of clinical importance related to this unique antigen/antibody system (alpha-gal epitope/anti-Gal) in improving the efficacy of viral vaccines and in immunotherapy against cancer.
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Fischer-Lougheed J, Gregory C, White Z, Shulkin I, Gunthart M, Kearns-Jonker M. Identification of an anti-idiotypic antibody that defines a B-cell subset(s) producing xenoantibodies in primates. Immunology 2007; 123:390-7. [PMID: 17916162 DOI: 10.1111/j.1365-2567.2007.02704.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Synthetic anti-idiotypic antibodies represent a potentially valuable tool for the isolation and characterization of B cells that produce xenoantibodies. An anti-idiotypic antibody that binds to a subset of B cells producing antibodies encoded by the variable-region heavy chain 3 (V(H)3) germline genes DP35 [immunoglobulin variable-region heavy chain 3-11 (IGHV3-11)], DP-53 and DP-54 plus a small number of V(H)4 gene-encoded antibodies in humans has recently been identified. These germline progenitors also encode xenoantibodies in humans. We tested whether the small, clearly defined group of B cells identified with this anti-idiotypic antibody produce xenoantibodies in non-human primates mounting active immune responses to porcine xenografts. Peripheral blood B cells were sorted by flow cytometry on the basis of phenotype, and cDNA libraries were prepared from each of these sorted groups of cells. Immunoglobulin V(H) gene libraries were prepared from the sorted cells, and the V(H) genes expressed in each of the sorted groups were identified by nucleic acid sequencing. Our results indicate that xenoantibody-producing peripheral blood B cells, defined on the basis of binding to fluorescein isothiocyanate (FITC)-conjugated galactose alpha(1,3) galactose-bovine serum albumin (Gal-BSA) and the anti-idiotypic antibody 2G10, used the IGHV3-11 germline gene to encode xenoantibodies and were phenotypically CD11b+ (Mac-1+) and CD5-. This novel reagent may be used in numerous applications including definition of xenoantibody-producing B-cell subsets in humans and non-human primates and immunosuppression by depletion of B cells producing anti-Gal xenoantibodies.
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Affiliation(s)
- Jacqueline Fischer-Lougheed
- Department of Cardiothoracic Surgery, Saban Research Institute of the Children's Hospital of Los Angeles, University of Southern California Keck School of Medicine, Los Angeles, CA, USA
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Brandl U, Erhardt M, Michel S, Jöckle H, Burdorf L, Bittmann I, Rössle M, Mordstein V, Brenner P, Hammer C, Reichart B, Schmoeckel M. Soluble Galalpha(1,3)Gal conjugate combined with hDAF preserves morphology and improves function of cardiac xenografts. Xenotransplantation 2007; 14:323-32. [PMID: 17669174 DOI: 10.1111/j.1399-3089.2007.00410.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Cytotoxic anti-Galalpha(1,3)Gal antibodies play a key role in the rejection of pig organs transplanted into primates. Regimens reducing anti-Galalpha(1,3)Gal antibodies were associated with severe side effects unable to prevent antibody rebound until soluble synthetic oligosaccharides with terminal Galalpha(1,3)Gal inhibiting antigen binding became available. We displayed kinetics of anti-pig and anti-Galalpha(1,3)Gal IgM and IgG antibody levels using GAS914, a Galalpha(1,3)Gal trisaccharide conjugated to poly-l-lysine, and investigated corresponding changes of parameters of heart function. METHODS Using a working heart model, hDAF pig hearts were perfused with human blood containing GAS914 (group 1). As controls hDAF pig hearts (group 2) and landrace pig hearts (group 3) were perfused with human blood only. Levels of anti-Galalpha(1,3)Gal (IgM, IgG) and anti-pig antibodies were assessed to prove the effectiveness of GAS914. As parameters of heart function, cardiac output (CO), stroke work index (SWI), coronary blood flow (CBF) and coronary resistance were measured. Creatine phosphokinases, lactate dehydrogenase and aspartate aminotransferase were evaluated as markers of myocardial damage. Histological and immunohistochemical investigations were performed at the end of perfusion. RESULTS In group 1 an immediate and extensive reduction in both IgM and IgG anti-Galalpha(1,3)Gal was found. Anti-pig antibodies were eliminated accordingly. Antibody binding to GAS914 was complete before the start of organ perfusion. Corresponding to rapid antibody elimination in group 1 GAS914 not only was able to significantly prolong the beating time of the heart in hDAF pigs, but also to clearly improve functional parameters. When switching to the working heart mode hDAF pig hearts perfused with human blood containing GAS914 (group 1) revealed a CO starting at a significantly higher level than hDAF (group 2) and non-transgenic pig hearts (group 3) perfused with human blood only. Similarly, in group 1 SWI was significantly increased at the beginning of perfusion compared to that of group 2 and group 3. The increase in CBF during perfusion and the corresponding fall of coronary resistance occurred without significant differences between the groups revealing the independence of hDAF and GAS914. CONCLUSIONS Due to an immediate and profound reduction in Galalpha(1,3)Gal-specific antibodies, soluble Galalpha(1,3)Gal conjugates not only prolong survival, but also improve the hemodynamic performance of the heart in DAF pigs.
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Affiliation(s)
- Ulrike Brandl
- Department of Cardiac Surgery, Ludwig-Maximilians-University Munich, Munich, Germany.
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Dwyer KM, Deaglio S, Crikis S, Gao W, Enjyoji K, Strom TB, Cowan PJ, d'Apice AJ, Robson SC. Salutary roles of CD39 in transplantation. Transplant Rev (Orlando) 2007. [DOI: 10.1016/j.trre.2007.01.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Abstract
A series of immunological and physiological barriers must be overcome for the successful clinical application of xenotransplantation. The acute phases of xenograft rejection have been prevented or at least attenuated by a variety of interventions including treatment of the recipient and genetic modification of the donor. However, recent data suggest that xenografts have a heightened susceptibility to intravascular thrombosis, a process that is emerging as a major contributor to xenograft loss. Current data strongly suggest that thrombosis is primarily a direct consequence of the rejection process, but it may also be facilitated by the failure of porcine regulators of coagulation to efficiently regulate the primate coagulation cascade. Systemic anticoagulant therapy has met with limited success and poses significant risks. Genetic strategies to express antithrombotic agents on xenograft endothelium appear to be more promising and achievable, with candidate molecules including human and leech anticoagulants and the antiplatelet enzyme CD39. Deletion of porcine procoagulants may also prove to be a useful approach.
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Affiliation(s)
- Sandra Crikis
- Immunology Research Centre and the Department of Medicine, St. Vincent's Health, University of Melbourne, Melbourne, Australia
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Wang J, Zhang B, Fang J, Sujino K, Li H, Otter A, Hindsgaul O, Palcic MM, Wang PG. Frontal Affinity Chromatography Coupled to Mass Spectrometry: An Effective Method for KdDetermination and Screening of α‐Gal Derivatives Binding to Anti‐Gal Antibodies (IgG). J Carbohydr Chem 2006. [DOI: 10.1081/car-120025323] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Jianqiang Wang
- a Department of Chemistry , University of Alberta , Edmonton, Alberta, T6G 2G2, Canada
- b Department of Chemistry , Wayne State University , Detroit, Michigan, 48202, USA
- c Triad Therapeutics, Inc. , 9381 Judicial Drive, San Diego, California, 92121, USA
| | - Boyan Zhang
- a Department of Chemistry , University of Alberta , Edmonton, Alberta, T6G 2G2, Canada
| | - Jianwen Fang
- b Department of Chemistry , Wayne State University , Detroit, Michigan, 48202, USA
| | - Keiko Sujino
- a Department of Chemistry , University of Alberta , Edmonton, Alberta, T6G 2G2, Canada
| | - Hong Li
- a Department of Chemistry , University of Alberta , Edmonton, Alberta, T6G 2G2, Canada
| | - Albin Otter
- a Department of Chemistry , University of Alberta , Edmonton, Alberta, T6G 2G2, Canada
| | - Ole Hindsgaul
- a Department of Chemistry , University of Alberta , Edmonton, Alberta, T6G 2G2, Canada
| | - Monica M. Palcic
- a Department of Chemistry , University of Alberta , Edmonton, Alberta, T6G 2G2, Canada
| | - Peng George Wang
- b Department of Chemistry , Wayne State University , Detroit, Michigan, 48202, USA
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Galili U. Xenotransplantation and ABO incompatible transplantation: The similarities they share. Transfus Apher Sci 2006; 35:45-58. [PMID: 16905361 DOI: 10.1016/j.transci.2006.05.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Accepted: 05/19/2006] [Indexed: 11/15/2022]
Abstract
Transplantation of kidney allografts across the ABO barrier has been feasible with the development of technologies for removal of anti-blood group antibodies from the circulation of the recipent. The recipients of ABO incompatible grafts display tolerance, accommodation or rejection of the graft. Understanding the factors that determine the outcome of the immune response against incompatible blood group antigens has required the study of an appropriate experimental animal model. The model used is that of knockout (KO) mice for the alpha1,3galactosyltransferase gene, lacking the alpha-gal epitopes and transplanted with wild type mouse heart expressing the alpha-gal epitope. The alpha-gal epitope (Galalpha1-3Galbeta1-(3)4GlcNAc-R) is one of the most abundant carbohydrate epitopes on cells of non-primate mammals and New World monkeys, where it is synthesized by the glycosylation enzyme alpha1,3galactosyltransferase. In humans, apes and Old World monkeys, this epitope is absent due to an evolutionary event that led to the inactivation of the alpha1,3galactosyltransferase gene in ancestral Old World primates. Instead, humans, apes and Old World monkeys produce a natural antibody, the anti-Gal antibody, that is the most abundant natural antibody in humans (approximately 1% of circulating immunoglobulins) and which specifically interacts with alpha-gal epitopes. The interaction between anti-Gal and alpha-gal epitopes is a major immunologic barrier in xenotransplantation, preventing transplantation of pig organs or tissues (i.e. xenografts) into humans. Anti-Gal antibodies also comprise a large proportion of anti-blood group B activity in A and O individuals. Moreover, in recipients of ABO incompatible grafts, much of the elicited anti-A and anti-B antibodies are in fact anti-Gal antibodies capable of binding also to the incompatible blood group antigens. Since the alpha-gal epitope is very similar in its structure to blood groups A and B, understanding anti-Gal response to alpha-gal epitopes is likely to provide information on the immune response to ABO incompatible antigens. Studies on the immune response to alpha-gal epitopes in KO mice have indicated that this epitope can not activate T cells. Anti-Gal B cells engaging alpha-gal epitopes on transplated wild type mouse heart can be activated to produce their antibodies only if they receive help from T cells that are activated by allogeneic or xenogeneic peptides. If T cell help is not available for several days the B cells are induced to differentiate into cells capable of producing accommodating antibodies. Accommodating anti-Gal antibodies bind to the incompatible carbohydrate antigen but do not induce rejection. Prolonged exposure of anti-Gal B cells to the incompatible alpha-gal epitope on the wild type mouse heart graft induces tolerance due to the deletion of these B cells. These studies imply that similar variation in the availability of T cell help in recipients of ABO incompatible grafts result in rejection, accommodation or tolerance, to the blood group antigen. The studies on immune response to incompatible alpha-gal epitopes have further indicated that tolerance to incompatible blood group antigens can be achieved by gene therapy with autologous bone marrow cells or autologous lymphocytes engineered to express the incompatible blood group antigen. Studies in the mouse model suggest that administration into the patient such autologous cells engineered to express the incompatible transplantation carbohydrate antigen induces deletion of anti-blood group B cells and induction of tolerance, provided that the anti-blood group antibodies are removed. Such tolerance is perpetuated indefinitely by the subsequent transplantation of the organ expressing the incompatible blood group antigen.
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Affiliation(s)
- Uri Galili
- Department of Medicine, University of Massachusetts Medical School, LRB, Worcester, MA 01605, USA.
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Shimizu I, Tomita Y, Iwai T, Kajiwara T, Okano S, Nomoto K, Tominaga R. Sequential analysis of anti-alpha Gal natural antibody-producing B cells in GalT knockout mice in cyclophosphamide-induced tolerance. Scand J Immunol 2006; 63:435-43. [PMID: 16764697 DOI: 10.1111/j.1365-3083.2006.001763.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Previously, we have shown that cyclophosphamide (CP)-induced tolerance, marked by permanent acceptance of donor skin graft and establishment of donor mixed chimerism, was readily induced with treatment with donor spleen cells (SC), CP, busulfan (BU) and donor bone marrow cells (BMC). Here, we investigated the mechanism of anti-donor natural antibody (nAb) producing B-cell tolerance in our CP-induced tolerance systems in alpha1,3-galactosyltransferase-deficient knockout mice (GalT KO; GalT-/-, H-2(b/d)). After induction of tolerance using donor AKR SC and BMC, survival of donor heart and skin grafts and production of anti-Galalpha1-3Galbeta1-4GlcNAc (anti-alphaGal) Ab in recipient GalT KO mice were analyzed. In addition, the production of anti-alphaGal Ab and the presence of Gal-BSA binding B cells in GalT KO mice were analyzed by flow cytometry (FCM) after treatments with rabbit red blood cells (RRBC) and CP. Permanent acceptance of donor skin and heart grafts and abrogation of anti-alphaGal Ab were achieved in GalT KO mice treated with donor SC + CP/BU + BMC. However, in the GalT KO mice treated with donor SC and CP, donor skin grafts were acutely rejected, even though anti-alphaGal Ab was undetectable. Similarly, anti-alphaGal Ab was undetectable in GalT KO mice treated with RRBC and CP. Our data strongly indicated the following mechanisms: the clonal destruction in the early stage and the clonal anergy or ignorance in the late stage after conventional conditioning with RRBC and CP. In conclusion, our drug-induced tolerance protocols are effective to induce tolerance in recipients that produce anti-donor nAb.
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Affiliation(s)
- Ichiro Shimizu
- Department of Cardiovascular Surgery, Kyushu University, Fukuoka, Japan
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Mitsuhashi N, Fischer-Lougheed J, Shulkin I, Kleihauer A, Kohn DB, Weinberg KI, Starnes VA, Kearns-Jonker M. Tolerance induction by lentiviral gene therapy with a nonmyeloablative regimen. Blood 2006; 107:2286-93. [PMID: 16291598 DOI: 10.1182/blood-2005-03-1172] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractAntibodies (Abs) directed at the Galα1,3Galβ1,4GlcNAc-R (αGal) carbohydrate epitope initiate xenograft rejection. Previously, we have shown that bone marrow transplantation (BMT) with lentivirus-mediated gene transfer of porcine α1,3 galactosyltransferase (GalT) is able to induce tolerance to αGal-expressing heart grafts following a lethal dose of irradiation. Here we show the first demonstration of permanent survival of αGal+ hearts following transplantation with autologous, lentivirus-transduced BM using a nonmyeloablative regimen. Autologous BM from GalT knockout (GalT–/–) mice was transduced with a lentiviral vector expressing porcine GalT and transplanted into sublethally irradiated (3 Gy) GalT–/– mice. Chimerism in the peripheral blood cells (PBCs) remained low but was higher in the BM, especially within the stromal cell population. Mice reconstituted with GalT did not produce anti-αGal Abs over time. We immunized these mice with αGal-expressing cells and assessed humoral immune responses. Anti-αGal xenoantibodies were not produced in mice reconstituted with GalT, but normal Ab responses to other xenoantigens were detected. Mice reconstituted with GalT accepted αGal+ heart grafts over 100 days. Transduction with lentiviral vectors results in chimerism at levels sufficient to induce long-term tolerance under nonmyeloablative conditions.
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Affiliation(s)
- Noboru Mitsuhashi
- Childrens Hospital of Los Angeles, Department of Cardiothoracic Surgery, Los Angeles, CA 90027, USA
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Galili U. The alpha-gal epitope and the anti-Gal antibody in xenotransplantation and in cancer immunotherapy. Immunol Cell Biol 2005; 83:674-86. [PMID: 16266320 DOI: 10.1111/j.1440-1711.2005.01366.x] [Citation(s) in RCA: 253] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The alpha-gal epitope (Galalpha1-3Galbeta1-(3)4GlcNAc-R) is abundantly synthesized on glycolipids and glycoproteins of non-primate mammals and New World monkeys by the glycosylation enzyme alpha1,3galactosyltransferase (alpha1,3GT). In humans, apes and Old World monkeys, this epitope is absent because the alpha1,3GT gene was inactivated in ancestral Old World primates. Instead, humans, apes and Old World monkeys produce the anti-Gal antibody, which specifically interacts with alpha-gal epitopes and which constitutes approximately 1% of circulating immunoglobulins. Anti-Gal has functioned as an immunological barrier, preventing the transplantation of pig organs into humans, because anti-Gal binds to the alpha-gal epitopes expressed on pig cells. The recent generation of alpha1,3GT knockout pigs that lack alpha-gal epitopes has resulted in the elimination of this immunological barrier. Anti-Gal can be exploited for clinical use in cancer immunotherapy by targeting autologous tumour vaccines to APC, thereby increasing their immunogenicity. Autologous intact tumour cells from haematological malignancies, or autologous tumour cell membranes from solid tumours are processed to express alpha-gal epitopes by incubation with neuraminidase, recombinant alpha1,3GT and with uridine diphosphate galactose. Subsequent immunization with such autologous tumour vaccines results in in vivo opsonization by anti-Gal IgG binding to these alpha-gal epitopes. The interaction of the Fc portion of the vaccine-bound anti-Gal with Fcgamma receptors of APC induces effective uptake of the vaccinating tumour cell membranes by the APC, followed by effective transport of the vaccinating tumour membranes to the regional lymph nodes, and processing and presentation of the tumour-associated antigen (TAA) peptides. Activation of tumour-specific T cells within the lymph nodes by autologous TAA peptides may elicit an immune response that in some patients will be potent enough to eradicate the residual tumour cells that remain after completion of standard therapy. A similar expression of alpha-gal epitopes can be achieved by transduction of tumour cells with an adenovirus vector (or other vectors) containing the alpha1,3GT gene, thus enabling anti-Gal-mediated targeting of the vaccinating transduced cells to APC. Intratumoral delivery of the alpha1,3GT gene by various vectors results in the expression of alpha-gal epitopes. Such expression of the xenograft carbohydrate phenotype is likely to induce anti-Gal-mediated destruction of the tumour lesion, similar to rejection of xenografts by this antibody. Opsonization of the destroyed tumour cell membranes by anti-Gal IgG further targets them to APC, thus converting the tumour lesion, treated by the alpha1,3GT gene, into an in situ autologous tumour vaccine.
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Affiliation(s)
- Uri Galili
- Division of Hematology/Oncology, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
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Holgersson J, Gustafsson A, Breimer ME. Characteristics of protein-carbohydrate interactions as a basis for developing novel carbohydrate-based antirejection therapies. Immunol Cell Biol 2005; 83:694-708. [PMID: 16266322 DOI: 10.1111/j.1440-1711.2005.01373.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The relative shortage of human organs for transplantation is today the major barrier to a broader use of transplantation as a means of treating patients with end-stage organ failure. This barrier could be partly overcome by an increased use of blood group ABO-incompatible live donors, and such trials are currently underway at several transplant centres. If xenotransplantation can be used clinically in the future, the human organ shortage will, in principle, be eradicated. In both these cases, carbohydrate antigens and the corresponding anti-carbohydrate antibodies are the major primary immunological barriers to overcome. Refined carbohydrate-based therapeutics may permit an increased number of ABO-incompatible transplantations to be carried out, and may remove the initial barriers to clinical xenotransplantation. Here, we will discuss the chemical characteristics of protein-carbohydrate interactions and outline carbohydrate-based antirejection therapies as used today in experimental as well as in clinical settings. Novel mucin-based adsorbers of natural anti-carbohydrate antibodies will also be described.
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Affiliation(s)
- Jan Holgersson
- Division of Clinical Immunology, Karolinska Institute, Karolinska University Hospital at Huddinge, Stockholm, Sweden
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Milland J, Christiansen D, Sandrin MS. α1,3‐Galactosyltransferase knockout pigs are available for xenotransplantation: Are glycosyltransferases still relevant? Immunol Cell Biol 2005; 83:687-93. [PMID: 16266321 DOI: 10.1111/j.1440-1711.2005.01398.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the early 1990s, the Galalpha(1,3)Gal carbohydrate linkage was found to be the major xenoepitope causing hyperacute rejection. This carbohydrate, the antibodies that bind to it, and the enzyme that produces it (alpha1,3-galactosyltransferase) were the foci of research by many groups. Nearly a decade later, alpha1,3-galactosyltransferase knockout pigs were finally produced; hyperacute rejection could be avoided in these pigs. Having achieved this goal, enthusiasm declined for the study of glycosyltransferases and their carbohydrate products. To examine whether this decline was premature, we evaluate whether gene deletion has indeed solved the initial rejection problem or, in fact, created new problems. This review addresses this by examining the impact of the gene deletion on cell surface carbohydrate. Surprisingly, Galalpha(1,3)Gal is still present in alpha1,3-galactosyltransferase knockout animals: it is possibly synthesized on lipid by iGb3 synthase. Furthermore, removal of alphaGal resulted in the exposure of the N-acetyllactosamine epitope. This exposed epitope can bind natural antibodies and perhaps should be capped by transgenic expression of another transferase. We believe the continued study of glycosyltransferases is essential to examine the new issues raised by the deletion of alpha1,3-galactosyltransferase.
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Affiliation(s)
- Julie Milland
- The Austin Research Institute, Austin Health, Melbourne, Victoria, Australia
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Foldvari M, Jaafari MR, Radhi J, Segal D. Efficacy of the antiadhesin octyl O-(2-acetamido-2-deoxy-beta-D-galactopyranosyl)-(1-4)-2-O-propyl-beta-D-galactopyranoside (Fimbrigal-P) in a rat oral candidiasis model. Antimicrob Agents Chemother 2005; 49:2887-94. [PMID: 15980365 PMCID: PMC1168655 DOI: 10.1128/aac.49.7.2887-2894.2005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Adherence of Candida albicans to buccal epithelial cells via its fimbrial subunit requires the minimal disaccharide sequence beta-GalNAc(1-4)-beta-galactosidase in host cell receptors asialo-GM1 or asialo-GM2. This and other disaccharides and some of its synthetic derivatives have been shown to inhibit purified fimbrial or pathogen binding in vitro. This study evaluates the in vivo efficacy of the propyl derivative of this disaccharide, octyl O-(2-acetamido-2-deoxy-beta-D-galactopyranosyl)-(1-4)-2-O-propyl-beta-D-galactopyranoside, or Fimbrigal-P, incorporated into a mucoadhesive polymer formulation in a rat oral candidiasis model. Colony counts of microcurette samples from the oral cavity and tongue homogenates were used to estimate the effectiveness of four treatment modalities to reduce oral fungal burden. All treatment modalities (preventative, premixing with the Candida inoculant, drinking water, and treatment) significantly reduced fungal burden compared to untreated control animals by day 9; however, the preventative and pre-mixing approaches provided a faster rate of fungal clearance. The low toxicity and immunogenicity of this synthetic carbohydrate and its stability in saliva, as demonstrated by high-performance liquid chromatography, make it a promising candidate for the prevention and treatment of microbial infections in which the pathogen relies on the beta-GalNAc(1-4)-beta-galactosidase disaccharide to establish adherence.
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Affiliation(s)
- M Foldvari
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada.
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Abstract
The success of allotransplantation has led to an increasing shortage of human organs from deceased donors. This crisis could be resolved by the use of organs from an anatomically suitable animal, such as the pig. The pig and human have, however, been evolving differently for approximately 80 million years, and numerous immunological and physiological barriers have developed that need to be overcome. Differences in carbohydrate epitopes on pig and human cells have been found to play a major role in some of the immunological barriers that have been identified to date. The rejection caused by the presence of galactose-alpha1,3-galactose (Gal) on the pig vascular endothelium and of natural anti-Gal antibodies in humans has recently been prevented by the breeding of pigs that do not express Gal, achieved by knocking out the gene for the enzyme alpha1,3-galactosyltransferase, which was made possible by the introduction of nuclear transfer/embryo transfer techniques. N-glycolylneuraminic acid (the so-called Hanganutziu-Deicher antigen) has been identified as another carbohydrate antigen present in pigs that may need to be deleted if xenotransplantation is to be successful, although some doubt remains regarding its importance. There remain other antipig antibodies against hitherto unidentified antigenic targets that may well be involved in graft destruction; their possible carbohydrate target epitopes are discussed.
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Affiliation(s)
- Mohamed Ezzelarab
- Thomas E Starzl Transplantation Institute, University of Pittsburgh MedicalCenter, Pittsburgh, Pennsylvania 15261, USA
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Wang Y, Yan Q, Wu J, Zhang LH, Ye XS. A new one-pot synthesis of α-Gal epitope derivatives involved in the hyperacute rejection response in xenotransplantation. Tetrahedron 2005. [DOI: 10.1016/j.tet.2005.02.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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