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Oh JW, Yoon CH, Ryu JS, Kim KP, Kim MK. Proteomics Analysis of Aqueous Humor and Rejected Graft in Pig-to-Non-Human Primate Corneal Xenotransplantation. Front Immunol 2022; 13:859929. [PMID: 35401527 PMCID: PMC8986976 DOI: 10.3389/fimmu.2022.859929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 02/25/2022] [Indexed: 11/23/2022] Open
Abstract
Although pig-to-non-human primate (NHP) corneal xenotransplantation has shown long-term graft survival, xenogeneic antigen-related immune responses are still stronger than allogeneic antigen-associated responses. Therefore, there is an unmet need to investigate major rejection pathways in corneal xenotransplantation, even with immunosuppression. This study aimed to identify biomarkers in aqueous humor for predicting rejection and to investigate rejection-related pathways in grafts from NHPs transplanted with porcine corneas following the administration of steroids combined with tacrolimus/rituximab. NHPs who had received corneas from wild-type (WT) or α-1,3-galactosyltransferase gene-knockout (GTKO) pigs were divided into groups with or without rejection according to clinical examinations. Liquid chromatography-mass spectrometry (LC-MS) was used to analyze the proteomes of corneal tissues or aqueous humor. The biological functions of differentially expressed proteins (DEPs) were assessed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) for pathways and protein–protein interaction network analysis. Among the 66 DEPs in aqueous humor, complement proteins (C3, C5, and C9) and cholesterol metabolic proteins (APOA1 and APOA2) were related to xenogeneic rejection as biomarkers, and alternative pathways of the complement system seemed to be important in xenogeneic graft rejection. Among the 416 DEPs of the cornea, NF-κB1 and proteosomes (PSMD7, PSMA5, and PSMD3) seemed to be related to xenogeneic graft rejection. Additionally, oxidative phosphorylation and leukocyte activation-related pathways are involved in rejection. Overall, our proteomic approach highlights the important role of NF-κB1, proteosomes, oxidative phosphorylation, and leukocyte activation-related inflammation in the cornea and the relevance of complement pathways of the aqueous humor as a predictive biomarker of xenogeneic rejection.
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Affiliation(s)
- Jae Won Oh
- Department of Applied Chemistry, Institute of Natural Science, Global Center for Pharmaceutical Ingredient Materials, Kyung Hee University, Yongin, South Korea
- Department of Biomedical Science and Technology, Kyung Hee Medical Science Research Institute, Kyung Hee University, Seoul, South Korea
| | - Chang Ho Yoon
- Laboratory of Ocular Regenerative Medicine and Immunology, Seoul Artificial Eye Center, Seoul National University Hospital Biomedical Research Institute, Seoul, South Korea
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, South Korea
- Department of Ophthalmology, Seoul National University Hospital, Seoul, South Korea
| | - Jin Suk Ryu
- Laboratory of Ocular Regenerative Medicine and Immunology, Seoul Artificial Eye Center, Seoul National University Hospital Biomedical Research Institute, Seoul, South Korea
| | - Kwang Pyo Kim
- Department of Applied Chemistry, Institute of Natural Science, Global Center for Pharmaceutical Ingredient Materials, Kyung Hee University, Yongin, South Korea
- Department of Biomedical Science and Technology, Kyung Hee Medical Science Research Institute, Kyung Hee University, Seoul, South Korea
- *Correspondence: Mee Kum Kim, ; Kwang Pyo Kim,
| | - Mee Kum Kim
- Laboratory of Ocular Regenerative Medicine and Immunology, Seoul Artificial Eye Center, Seoul National University Hospital Biomedical Research Institute, Seoul, South Korea
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, South Korea
- Department of Ophthalmology, Seoul National University Hospital, Seoul, South Korea
- Transplantation Research Institute, Seoul National University Medical Research Center, Seoul, South Korea
- *Correspondence: Mee Kum Kim, ; Kwang Pyo Kim,
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Li P, Walsh JR, Lopez K, Isidan A, Zhang W, Chen AM, Goggins WC, Higgins NG, Liu J, Brutkiewicz RR, Smith LJ, Hara H, Cooper DKC, Ekser B. Genetic engineering of porcine endothelial cell lines for evaluation of human-to-pig xenoreactive immune responses. Sci Rep 2021; 11:13131. [PMID: 34162938 PMCID: PMC8222275 DOI: 10.1038/s41598-021-92543-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 06/08/2021] [Indexed: 01/25/2023] Open
Abstract
Xenotransplantation (cross-species transplantation) using genetically-engineered pig organs offers a potential solution to address persistent organ shortage. Current evaluation of porcine genetic modifications is to monitor the nonhuman primate immune response and survival after pig organ xenotransplantation. This measure is an essential step before clinical xenotransplantation trials, but it is time-consuming, costly, and inefficient with many variables. We developed an efficient approach to quickly examine human-to-pig xeno-immune responses in vitro. A porcine endothelial cell was characterized and immortalized for genetic modification. Five genes including GGTA1, CMAH, β4galNT2, SLA-I α chain, and β2-microglobulin that are responsible for the production of major xenoantigens (αGal, Neu5Gc, Sda, and SLA-I) were sequentially disrupted in immortalized porcine endothelial cells using CRISPR/Cas9 technology. The elimination of αGal, Neu5Gc, Sda, and SLA-I dramatically reduced the antigenicity of the porcine cells, though the cells still retained their ability to provoke human natural killer cell activation. In summary, evaluation of human immune responses to genetically modified porcine cells in vitro provides an efficient method to identify ideal combinations of genetic modifications for improving pig-to-human compatibility, which should accelerate the application of xenotransplantation to humans.
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Affiliation(s)
- Ping Li
- Division of Transplant Surgery, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA.
| | - Julia R Walsh
- Division of Transplant Surgery, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA.,Weldon School of Biomedical Engineering, West Lafayette, IN, USA
| | - Kevin Lopez
- Division of Transplant Surgery, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Abdulkadir Isidan
- Division of Transplant Surgery, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Wenjun Zhang
- Division of Transplant Surgery, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Angela M Chen
- Division of Transplant Surgery, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - William C Goggins
- Division of Transplant Surgery, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | | | - Jianyun Liu
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Randy R Brutkiewicz
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Lester J Smith
- Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA.,3D Bioprinting Core, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Hidetaka Hara
- Xenotransplantation Program, Department of Surgery, University of Birmingham at Alabama, Birmingham, AL, USA
| | - David K C Cooper
- Xenotransplantation Program, Department of Surgery, University of Birmingham at Alabama, Birmingham, AL, USA
| | - Burcin Ekser
- Division of Transplant Surgery, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA.
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Burlak C, Taylor RT, Wang ZY, Tector AJ. Human anti‐α‐fucose antibodies are xenoreactive toward GGTA1/CMAH knockout pigs. Xenotransplantation 2020; 27:e12629. [DOI: 10.1111/xen.12629] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 05/28/2020] [Accepted: 06/22/2020] [Indexed: 11/29/2022]
Affiliation(s)
| | - R. Travis Taylor
- Department of Medical Microbiology and Immunology University of Toledo Medical Center Toledo OH USA
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Byrne G, Ahmad-Villiers S, Du Z, McGregor C. B4GALNT2 and xenotransplantation: A newly appreciated xenogeneic antigen. Xenotransplantation 2018; 25:e12394. [PMID: 29604134 PMCID: PMC6158069 DOI: 10.1111/xen.12394] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 03/08/2018] [Accepted: 03/13/2018] [Indexed: 12/20/2022]
Abstract
Analysis of non‐Gal antibody induced after pig‐to‐baboon cardiac xenotransplantation identified the glycan produced by porcine beta‐1,4‐N‐acetyl‐galactosaminyltransferase 2 (B4GALNT2) as an immunogenic xenotransplantation antigen. The porcine B4GALNT2 enzyme is homologous to the human enzyme, which synthesizes the human SDa blood group antigen. Most humans produce low levels of anti‐SDa IgM which polyagglutinates red blood cells from rare individuals with high levels of SDa expression. The SDa glycan is also present on GM2 gangliosides. Clinical GM2 vaccination studies for melanoma patients suggest that a human antibody response to SDa can be induced. Expression of porcine B4GALNT2 in human HEK293 cells results in increased binding of anti‐SDa antibody and increased binding of Dolichos biflorus agglutinin (DBA), a lectin commonly used to detect SDa. In pigs, B4GALNT2 is expressed by vascular endothelial cells and endothelial cells from a wide variety of pig backgrounds stain with DBA, suggesting that porcine vascular expression of B4GALNT2 is not polymorphic. Mutations in B4GALNT2 have been engineered in mice and pigs. In both species, the B4GALNT2‐KO animals are apparently normal and no longer show evidence of SDa antigen expression. Pig tissues with a mutation in B4GALNT2, added to a background of alpha‐1,3‐galactosyltransferase deficient (GGTA1‐KO) and cytidine monophosphate‐N‐acetylneuraminic acid hydroxylase deficient (CMAH‐KO), show reduced antibody binding, confirming the presence of B4GALNT2‐dependent antibodies in both humans and non‐human primates. Preclinical xenotransplantation using B4GALNT2‐deficient donors has recently been reported. Elimination of this source of immunogenic pig antigen should minimize acute injury by preformed anti‐pig antibody and eliminate an induced clinical immune response to this newly appreciated xenotransplantation antigen.
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Affiliation(s)
- Guerard Byrne
- Institute of Cardiovascular Science, University College London, London, UK.,Department of Surgery, Mayo Clinic, Rochester, MN, USA
| | | | - Zeji Du
- Department of Surgery, Mayo Clinic, Rochester, MN, USA
| | - Christopher McGregor
- Institute of Cardiovascular Science, University College London, London, UK.,Department of Surgery, Mayo Clinic, Rochester, MN, USA
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5
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Zhang Z, Gao B, Zhao C, Long C, Qi H, Ezzelarab M, Cooper DK, Hara H. The impact of serum incubation time on IgM/IgG binding to porcine aortic endothelial cells. Xenotransplantation 2017; 24. [PMID: 28547819 DOI: 10.1111/xen.12312] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 04/05/2017] [Accepted: 04/06/2017] [Indexed: 12/25/2022]
Abstract
The results of the assay for measuring anti-non-Gal antibodies (which affect pig xenograft survival) in recipients are important. Serum incubation time and concentration may be important factors in the extent of antibody binding to the graft. The aim of this in vitro study was to determine the optimal incubation time and serum concentration for measuring anti-non-Gal antibody binding to porcine aortic endothelial cells (pAECs). Pooled human, naive, and sensitized baboon sera were incubated with wild-type, α1,3-galactosyltransferase gene-knockout (GTKO), and GTKO/human CD55 pAECs. IgM/IgG binding to pAECs after varying serum incubation times (0.5, 1, 2, and 3 hour) and concentrations (5, 10, 20, and 40 μL) was determined by flow cytometry. An increase in incubation time from 30 minutes to 2 hour was associated with increases in anti-non-Gal IgM/IgG binding to GTKO and GTKO/hCD55 pAECs of pooled human, naive and sensitized baboon sera (P<.05). Pooled human serum showed a significant increase in anti-non-Gal IgM (1.5 times) and a minimal increase in anti-non-Gal IgG antibody binding. IgM/IgG binding of sensitized baboon serum to GTKO pAECs after 2-hour incubation was 1.5 times and 2 times greater than after 30-minutes incubation, respectively, whereas naïve baboon sera showed minimal (non-significant) increase in anti-non-Gal IgM/IgG antibody binding. With 2-hour incubation, increasing the serum concentration from 5 μL to 20 μL significantly increased antibody binding to non-Gal antigens in pooled human and sensitized baboon serum. With naïve baboon serum, only IgG was significantly increased. Increasing the serum incubation time contributed to improve the sensitivity of detecting anti-non-Gal antibodies, without affecting cell viability in vitro.
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Affiliation(s)
- Zhongqiang Zhang
- Department of Organ Transplantation and General Surgery, Second Xiangya Hospital of the Central South University, Hunan, Changsha, China.,Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, USA
| | - Bingsi Gao
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, USA
| | - Chengjiang Zhao
- Shenzhen Xenotransplantation Medical Engineering Research and Development Center, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen, China
| | - Cassandra Long
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, USA
| | - Haizhi Qi
- Department of Organ Transplantation and General Surgery, Second Xiangya Hospital of the Central South University, Hunan, Changsha, China
| | - Mohamed Ezzelarab
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, USA
| | - David Kc Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, USA
| | - Hidetaka Hara
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, USA
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Abstract
The availability of cells, tissues and organs from a non-human species such as the pig could, at least in theory, meet the demand of organs necessary for clinical transplantation. At this stage, the important goal of getting over the first year of survival has been reported for both cellular and solid organ xenotransplantation in relevant preclinical primate models. In addition, xenotransplantation is already in the clinic as shown by the broad use of animal-derived medical devices, such as bioprosthetic heart valves and biological materials used for surgical tissue repair. At this stage, however, prior to starting a wide-scale clinical application of xenotransplantation of viable cells and organs, the important obstacle represented by the humoral immune response will need to be overcome. Likewise, the barriers posed by the activation of the innate immune system and coagulative pathway will have to be controlled. As far as xenogeneic nonviable xenografts, increasing evidence suggests that considerable immune reactions, mediated by both innate and adaptive immunity, take place and influence the long-term outcome of xenogeneic materials in patients, possibly precluding the use of bioprosthetic heart valves in young individuals. In this context, the present article provides an overview of current knowledge on the immune processes following xenotransplantation and on the possible therapeutic interventions to overcome the immunological drawbacks involved in xenotransplantation.
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Affiliation(s)
- M Vadori
- CORIT (Consortium for Research in Organ Transplantation), Via dell'Università 10, 35020 Legnaro, Padua, Italy
| | - E Cozzi
- CORIT (Consortium for Research in Organ Transplantation), Via dell'Università 10, 35020 Legnaro, Padua, Italy.,Transplant Immunology Unit, Department of Transfusion Medicine, Padua University Hospital, Via Giustiniani, 2, 35128 Padua, Italy
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7
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Lin Y, Miyagi N, Byrne GW, Du Z, Kogelberg H, Gazi MH, Tazelaar HD, Wang C, McGregor CGA. A pig-to-mouse coronary artery transplantation model for investigating the pathogenicity of anti-pig antibody. Xenotransplantation 2015; 22:458-67. [PMID: 26490445 PMCID: PMC10022689 DOI: 10.1111/xen.12198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 08/25/2015] [Indexed: 11/30/2022]
Abstract
BACKGROUND Rejection of Gal-free (GTKO) donor pig cardiac xenografts is strongly associated with vascular non-Gal antibody binding, endothelial cell (EC) injury, and activation and microvascular thrombosis. We adopted a pig-to-SCID/beige small animal transplant model to compare the pathogenicity of baboon and human anti-pig antibody. METHODS Wild-type (GT(+) ) or GTKO porcine coronary arteries (PCAs) were transplanted into the infrarenal aorta of SCID/beige mice. Three days after transplant, recipients were infused with anti-pig antibody (anti-SLA class I, an isotype control, naive or sensitized baboon serum, or naive human serum). PCAs were recovered 24 h after antibody infusion and examined using histology, immunohistochemistry, and in situ hybridization. RESULTS Dose-dependent intragraft thrombosis occurred after infusion of anti-SLA I antibody (but not isotype control) in GT(+) and GTKO PCA recipients. Naive baboon serum induced thrombosis in GT(+) grafts. Thrombosis was significantly reduced by pre-treating naive baboon serum with Gal polymer and not observed when this serum was infused to GTKO PCA recipients. Naive human serum caused dose-dependent intragraft thrombosis of GTKO PCAs. In all cases, thrombosis involved graft-specific vascular antibody and complement deposition, macrophage adherence, EC delamination, and subendothelial thrombus formation. CONCLUSIONS This study provides the first direct in vivo comparison of the pathogenicity of naive human and baboon serum. The results suggest that human preformed non-Gal antibody may have increased pathogenicity compared to baboon. This model, which showed a rejected graft histopathology similar to antibody-mediated rejection in cardiac xenotransplantation, may be useful to assess the pathogenicity of individual protein or carbohydrate specific non-Gal reactive antibodies.
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Affiliation(s)
- Yi Lin
- Department of Surgery, Mayo Clinic, Rochester, MN, USA.,Department of Cardiovascular Surgery, Zhongshan Hospital of Fudan University, Shanghai, China
| | - Naoto Miyagi
- Department of Surgery, Mayo Clinic, Rochester, MN, USA
| | - Guerard W Byrne
- Department of Surgery, Mayo Clinic, Rochester, MN, USA.,Institute of Cardiovascular Science, University College London, London, UK
| | - Zeji Du
- Department of Surgery, Mayo Clinic, Rochester, MN, USA
| | - Heide Kogelberg
- Institute of Cardiovascular Science, University College London, London, UK
| | | | - Henry D Tazelaar
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Scottsdale, AZ, USA
| | - Chunsheng Wang
- Department of Cardiovascular Surgery, Zhongshan Hospital of Fudan University, Shanghai, China
| | - Christopher G A McGregor
- Department of Surgery, Mayo Clinic, Rochester, MN, USA.,Institute of Cardiovascular Science, University College London, London, UK
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8
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Byrne GW, McGregor CGA, Breimer ME. Recent investigations into pig antigen and anti-pig antibody expression. Int J Surg 2015; 23:223-228. [PMID: 26306769 DOI: 10.1016/j.ijsu.2015.07.724] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 07/22/2015] [Accepted: 07/26/2015] [Indexed: 01/17/2023]
Abstract
Genetic engineering of donor pigs to eliminate expression of the dominant xenogeneic antigen galactose α1,3 galactose (Gal) has created a sea change in the immunobiology of xenograft rejection. Antibody mediated xenograft rejection of GGTA-1 α-galactosyltransferase (GTKO) deficient organs is now directed to a combination of non-Gal pig protein and carbohydrate antigens. Glycan analysis of GTKO tissues identified no new neo-antigens but detected high levels of N-acetylneuraminic acid (Neu5Gc) modified glycoproteins and glycolipids. Humans produce anti-Neu5Gc antibody and in very limited clinical studies sometimes show an induced anti-Neu5Gc antibody response after challenge with pig tissue. The pathogenicity of anti-Neu5Gc antibody in xenotransplantation is not clear however as non-human transplant models, critical for modelling anti-Gal immunity, do not produce anti-Neu5Gc antibody. Antibody induced after xenotransplantation in non-human primates is directed to an array of pig endothelial cells proteins and to a glycan produced by the pig B4GALNT2 gene. We anticipate that immune suppression will significantly affect the T-cell dependent and independent specificity of an induced antibody response and that donor pigs deficient in synthesis of multiple xenogeneic glycans will be important to future studies.
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Affiliation(s)
- Guerard W Byrne
- Department of Surgery, Mayo Clinic, Rochester, MN 55905, USA; Institute of Cardiovascular Science, University College London, London WC1E 6JF, UK.
| | - Christopher G A McGregor
- Department of Surgery, Mayo Clinic, Rochester, MN 55905, USA; Institute of Cardiovascular Science, University College London, London WC1E 6JF, UK
| | - Michael E Breimer
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy at Gothenburg University, Gothenburg, Sweden
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Azimzadeh AM, Byrne GW, Ezzelarab M, Welty E, Braileanu G, Cheng X, Robson SC, McGregor CGA, Cooper DKC, Pierson RN. Development of a consensus protocol to quantify primate anti-non-Gal xenoreactive antibodies using pig aortic endothelial cells. Xenotransplantation 2014; 21:555-66. [PMID: 25176173 DOI: 10.1111/xen.12125] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 05/30/2014] [Indexed: 01/05/2023]
Abstract
BACKGROUND Scientists working in the field of xenotransplantation do not employ a uniform method to measure and report natural and induced antibody responses to non-Galα(1,3)Gal (non-Gal) epitopes. Such humoral responses are thought to be particularly pathogenic after transplantation of vascularized GalTKO pig organs and having a more uniform assay and reporting format would greatly facilitate comparisons between laboratories. METHODS Flow cytometry allows examination of antibody reactivity to intact antigens in their natural location and conformation on cell membranes. We have established a simple and reproducible flow cytometric assay to detect antibodies specific for non-Gal pig antigens using primary porcine aortic endothelial cells (pAECs) and cell culture-adapted pAEC cell lines generated from wild type and α1,3galactosyl transferase knockout (GalTKO) swine. RESULTS The consensus protocol we propose here is based on procedures routinely used in four xenotransplantation centers and was independently evaluated at three sites using shared cells and serum samples. Our observation support use of the cell culture-adapted GalTKO pAEC KO:15502 cells as a routine method to determine the reactivity of anti-non-Gal antibodies in human and baboon serum. CONCLUSIONS We have developed an assay that allows the detection of natural and induced non-Gal xenoreactive antibodies present in human or baboon serum in a reliable and consistent manner. This consensus assay and format for reporting the data should be accessible to laboratories and will be useful for assessing experimental results between multiple research centers. Adopting this assay and format for reporting the data should facilitate the detection, monitoring, and detailed characterization of non-Gal antibody responses.
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Affiliation(s)
- Agnes M Azimzadeh
- Division of Cardiac Surgery, University of Maryland and VAMC Baltimore, Baltimore, MD, USA
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Stewart JM, Tarantal AF, Hawthorne WJ, Salvaris EJ, O'Connell PJ, Nottle MB, d'Apice AJF, Cowan PJ, Kearns-Jonker M. Rhesus monkeys and baboons develop clotting factor VIII inhibitors in response to porcine endothelial cells or islets. Xenotransplantation 2014; 21:341-52. [PMID: 24806998 DOI: 10.1111/xen.12100] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 03/14/2014] [Indexed: 01/15/2023]
Abstract
BACKGROUND Xenotransplantation of porcine organs holds promise of solving the human organ donor shortage. The use of α-1,3-galactosyltransferase knockout (GTKO) pig donors mitigates hyperacute rejection, while delayed rejection is currently precipitated by potent immune and hemostatic complications. Previous analysis by our laboratory suggests that clotting factor VIII (FVIII) inhibitors might be elicited by the structurally restricted xenoantibody response which occurs after transplantation of either pig GTKO/hCD55/hCD59/hHT transgenic neonatal islet cell clusters or GTKO endothelial cells. METHODS A recombinant xenoantibody was generated using sequences from baboons demonstrating an active xenoantibody response at day 28 after GTKO/hCD55/hCD59/hHT transgenic pig neonatal islet cell cluster transplantation. Rhesus monkeys were immunized with GTKO pig endothelial cells to stimulate an anti-non-Gal xenoantibody response. Serum was collected at days 0 and 7 after immunization. A two-stage chromogenic assay was used to measure FVIII cofactor activity and identify antibodies which inhibit FVIII function. Molecular modeling and molecular dynamics simulations were used to predict antibody structure and the residues which contribute to antibody-FVIII interactions. Competition ELISA was used to verify predictions at the domain structural level. RESULTS Antibodies that inhibit recombinant human FVIII function are elicited after non-human primates are transplanted with either GTKO pig neonatal islet cell clusters or endothelial cells. There is an apparent increase in inhibitor titer by 15 Bethesda units (Bu) after transplant, where an increase greater than 5 Bu can indicate pathology in humans. Furthermore, competition ELISA verifies the computer modeled prediction that the recombinant xenoantibody, H66K12, binds the C1 domain of FVIII. CONCLUSIONS The development of FVIII inhibitors is a novel illustration of the potential impact the humoral immune response can have on coagulative dysfunction in xenotransplantation. However, the contribution of these antibodies to rejection pathology requires further evaluation because "normal" coagulation parameters after successful xenotransplantation are not fully understood.
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Affiliation(s)
- John M Stewart
- Division of Human Anatomy, School of Medicine, Loma Linda University, Loma Linda, CA, USA
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11
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Stewart JM, Tarantal AF, Chen Y, Appleby NC, Fuentes TI, Lee CCI, Salvaris EJ, d'Apice AJF, Cowan PJ, Kearns-Jonker M. Anti-non-Gal-specific combination treatment with an anti-idiotypic Ab and an inhibitory small molecule mitigates the xenoantibody response. Xenotransplantation 2014; 21:254-66. [PMID: 24635144 DOI: 10.1111/xen.12096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 02/14/2014] [Indexed: 11/28/2022]
Abstract
BACKGROUND B-cell depletion significantly extends survival of α-1,3-galactosyltranferase knockout (GTKO) porcine organs in pig-to-primate models. Our previous work demonstrated that the anti-non-Gal xenoantibody response is structurally restricted. Selective inhibition of xenoantigen/xenoantibody interactions could prolong xenograft survival while preserving B-cell-mediated immune surveillance. METHODS The anti-idiotypic antibody, B4N190, was selected from a synthetic human phage display library after enrichment against a recombinant anti-non-Gal xenoantibody followed by functional testing in vitro. The inhibitory small molecule, JMS022, was selected from the NCI diversity set III using virtual screening based on predicted xenoantibody structure. Three rhesus monkeys were pre-treated with anti-non-Gal-specific single-chain anti-idiotypic antibody, B4N190. A total of five monkeys, including two untreated controls, were then immunized with GTKO porcine endothelial cells to initiate an anti-non-α-1,3-Gal (non-Gal) xenoantibody response. The efficacy of the inhibitory small molecule specific for anti-non-Gal xenoantibody, JMS022, was tested in vitro. RESULTS After the combination of in vivo anti-id and in vitro small molecule treatments, IgM xenoantibody binding to GTKO cells was reduced to pre-immunization levels in two-thirds of animals; however, some xenoantibodies remained in the third animal. Furthermore, when treated with anti-id alone, all three experimental animals displayed a lower anti-non-Gal IgG xenoantibody response compared with controls. Treatment with anti-idiotypic antibody alone reduced IgM xenoantibody response intensity in only one of three monkeys injected with GTKO pig endothelial cells. In the one experimental animal, which displayed reduced IgM and IgG responses, select B-cell subsets were also reduced by anti-id therapy alone. Furthermore, natural antibody responses, including anti-laminin, anti-ssDNA, and anti-thyroglobulin antibodies were intact despite targeted depletion of anti-non-Gal xenoantibodies in vivo indicating that selective reduction of xenoantibodies can be accomplished without total B-cell depletion. CONCLUSIONS This preliminary study demonstrates the strength of approaches designed to selectively inhibit anti-non-Gal xenoantibody. Both anti-non-Gal-specific anti-idiotypic antibody and small molecules can be used to selectively limit xenoantibody responses.
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Affiliation(s)
- John M Stewart
- Department of Human Anatomy, Loma Linda University School of Medicine, Loma Linda, CA, USA
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12
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Schneider MKJ, Seebach JD. Xenotransplantation literature update, September-October 2013. Xenotransplantation 2013; 20:481-6. [PMID: 24289471 DOI: 10.1111/xen.12076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 10/15/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Mårten K J Schneider
- Laboratory of Vascular Immunology, Division of Internal Medicine, University Hospital Zurich, Zurich, Switzerland
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