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Elalouf A, Elalouf H, Rosenfeld A. Modulatory immune responses in fungal infection associated with organ transplant - advancements, management, and challenges. Front Immunol 2023; 14:1292625. [PMID: 38143753 PMCID: PMC10748506 DOI: 10.3389/fimmu.2023.1292625] [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: 09/11/2023] [Accepted: 11/20/2023] [Indexed: 12/26/2023] Open
Abstract
Organ transplantation stands as a pivotal achievement in modern medicine, offering hope to individuals with end-stage organ diseases. Advancements in immunology led to improved organ transplant survival through the development of immunosuppressants, but this heightened susceptibility to fungal infections with nonspecific symptoms in recipients. This review aims to establish an intricate balance between immune responses and fungal infections in organ transplant recipients. It explores the fundamental immune mechanisms, recent advances in immune response dynamics, and strategies for immune modulation, encompassing responses to fungal infections, immunomodulatory approaches, diagnostics, treatment challenges, and management. Early diagnosis of fungal infections in transplant patients is emphasized with the understanding that innate immune responses could potentially reduce immunosuppression and promise efficient and safe immuno-modulating treatments. Advances in fungal research and genetic influences on immune-fungal interactions are underscored, as well as the potential of single-cell technologies integrated with machine learning for biomarker discovery. This review provides a snapshot of the complex interplay between immune responses and fungal infections in organ transplantation and underscores key research directions.
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Affiliation(s)
- Amir Elalouf
- Department of Management, Bar-Ilan University, Ramat Gan, Israel
| | - Hadas Elalouf
- Information Science Department, Bar-Ilan University, Ramat Gan, Israel
| | - Ariel Rosenfeld
- Information Science Department, Bar-Ilan University, Ramat Gan, Israel
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2
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MacNabb BW, Kline J. MHC cross-dressing in antigen presentation. Adv Immunol 2023; 159:115-147. [PMID: 37996206 DOI: 10.1016/bs.ai.2023.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2023]
Abstract
Dendritic cells (DCs) orchestrate T cell responses by presenting antigenic peptides on major histocompatibility complex (MHC) and providing costimulation and other instructive signals. Professional antigen presenting cells (APCs), including DCs, are uniquely capable of generating and presenting peptide antigens derived from exogenous proteins. In addition to these canonical cross-presentation and MHC-II presentation pathways, APCs can also display exogenous peptide/MHC (p/MHC) acquired from neighboring cells and extracellular vesicles (EVs). This process, known as MHC cross-dressing, has been implicated in the regulation of T cell responses in a variety of in vivo contexts, including allogeneic solid organ transplantation, tumors, and viral infection. Although the occurrence of MHC cross-dressing has been clearly demonstrated, the importance of this antigen presentation mechanism continues to be elucidated. The contribution of MHC cross-dressing to overall antigen presentation has been obfuscated by the fact that DCs express the same MHC alleles as all other cells in the host, making it difficult to distinguish p/MHC generated within the DC from p/MHC acquired from another cell. As a result, much of what is known about MHC cross-dressing comes from studies using allogeneic organ transplantation and bone marrow chimeric mice, though recent development of mice bearing conditional knockout MHC and β2-microglobulin alleles should facilitate substantial progress in the coming years. In this review, we highlight recent advances in our understanding of MHC cross-dressing and its role in activating T cell responses in various contexts, as well as the experimental insights into the mechanism by which it occurs.
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Affiliation(s)
- Brendan W MacNabb
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, United States.
| | - Justin Kline
- Department of Medicine, Committee on Immunology, and Committee on Cancer Biology, University of Chicago, Chicago, IL, United States.
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3
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Carnel N, Lancia HH, Guinier C, Benichou G. Pathways of Antigen Recognition by T Cells in Allograft Rejection. Transplantation 2023; 107:827-837. [PMID: 36398330 PMCID: PMC10600686 DOI: 10.1097/tp.0000000000004420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The adaptive immune response leading to the rejection of allogeneic transplants is initiated and orchestrated by recipient T cells recognizing donor antigens. T-cell allorecognition is mediated via 3 distinct mechanisms: the direct pathway in which T cells recognize allogeneic major histocompatibility complex (MHC) molecules on donor cells, the indirect pathway through which T cells interact with donor peptides bound with self-MHC molecules on recipient antigen-presenting cells, and the recently described semidirect pathway whereby T cells recognize donor MHC proteins on recipient antigen-presenting cells. In this article, we present a description of each of these allorecognition pathways and discuss their role in acute and chronic rejection of allogeneic transplants.
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Affiliation(s)
- Natacha Carnel
- Department of Surgery, Center for Transplantation Sciences, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Hyshem H. Lancia
- Department of Surgery, Center for Transplantation Sciences, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Claire Guinier
- Department of Surgery, Center for Transplantation Sciences, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Gilles Benichou
- Department of Surgery, Center for Transplantation Sciences, Massachusetts General Hospital, Harvard Medical School, Boston, MA
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4
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Cheung A, Levitsky J. CAQ Corner: Basic concepts of transplant immunology. Liver Transpl 2023; 29:331-339. [PMID: 37160065 PMCID: PMC9935643 DOI: 10.1002/lt.26501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/15/2022] [Accepted: 05/04/2022] [Indexed: 01/12/2023]
Affiliation(s)
- Amanda Cheung
- Division of Gastroenterology and Hepatology, Comprehensive Transplant Center , Northwestern University Feinberg School of Medicine , Chicago , Illinois , USA
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5
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Gangadaran P, Madhyastha H, Madhyastha R, Rajendran RL, Nakajima Y, Watanabe N, Velikkakath AKG, Hong CM, Gopi RV, Muthukalianan GK, Valsala Gopalakrishnan A, Jeyaraman M, Ahn BC. The emerging role of exosomes in innate immunity, diagnosis and therapy. Front Immunol 2023; 13:1085057. [PMID: 36726968 PMCID: PMC9885214 DOI: 10.3389/fimmu.2022.1085057] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 12/16/2022] [Indexed: 01/17/2023] Open
Abstract
Exosomes, which are nano-sized transport bio-vehicles, play a pivotal role in maintaining homeostasis by exchanging genetic or metabolic information between different cells. Exosomes can also play a vital role in transferring virulent factors between the host and parasite, thereby regulating host gene expression and the immune interphase. The association of inflammation with disease development and the potential of exosomes to enhance or mitigate inflammatory pathways support the notion that exosomes have the potential to alter the course of a disease. Clinical trials exploring the role of exosomes in cancer, osteoporosis, and renal, neurological, and pulmonary disorders are currently underway. Notably, the information available on the signatory efficacy of exosomes in immune-related disorders remains elusive and sporadic. In this review, we discuss immune cell-derived exosomes and their application in immunotherapy, including those against autoimmune connective tissue diseases. Further, we have elucidated our views on the major issues in immune-related pathophysiological processes. Therefore, the information presented in this review highlights the role of exosomes as promising strategies and clinical tools for immune regulation.
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Affiliation(s)
- Prakash Gangadaran
- BK21 FOUR KNU Convergence Educational Program of Biomedical Sciences for Creative Future Talents, Department of Biomedical Science, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
- Department of Nuclear Medicine, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Harishkumar Madhyastha
- Department of Cardiovascular Physiology, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Radha Madhyastha
- Department of Cardiovascular Physiology, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Ramya Lakshmi Rajendran
- Department of Nuclear Medicine, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Yuichi Nakajima
- Department of Cardiovascular Physiology, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Nozomi Watanabe
- Department of Cardiovascular Physiology, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Anoop Kumar G. Velikkakath
- Center for System Biology and Molecular Medicine, Yenepoya Research center, Yenepoya (Deemed to be University), Mangaluru, Karnataka, India
| | - Chae Moon Hong
- Department of Nuclear Medicine, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Rahul Velikkakath Gopi
- Department of Tissue Engineering and Regeneration Technologies, Sree Chitra Thirunal Institute of Medical Sciences and Technology, Thiruvananthapuram, India
| | | | | | - Madhan Jeyaraman
- Department of Orthopaedics, Faculty of Medicine, Sri Lalithambigai Medical College and Hospital, Dr MGR Educational and Research Institute, Chennai, Tamil Nadu, India
| | - Byeong-Cheol Ahn
- BK21 FOUR KNU Convergence Educational Program of Biomedical Sciences for Creative Future Talents, Department of Biomedical Science, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
- Department of Nuclear Medicine, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, Republic of Korea
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6
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Sanders JM, Jeyamogan S, Mathew JM, Leventhal JR. Foxp3+ regulatory T cell therapy for tolerance in autoimmunity and solid organ transplantation. Front Immunol 2022; 13:1055466. [PMID: 36466912 PMCID: PMC9714335 DOI: 10.3389/fimmu.2022.1055466] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/02/2022] [Indexed: 08/03/2023] Open
Abstract
Regulatory T cells (Tregs) are critical for tolerance in humans. The exact mechanisms by which the loss of peripheral tolerance leads to the development of autoimmunity and the specific role Tregs play in allograft tolerance are not fully understood; however, this population of T cells presents a unique opportunity in the development of targeted therapeutics. In this review, we discuss the potential roles of Foxp3+ Tregs in the development of tolerance in transplantation and autoimmunity, and the available data regarding their use as a treatment modality.
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Affiliation(s)
- Jes M. Sanders
- Department of Surgery, Comprehensive Transplant Center Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Shareni Jeyamogan
- Department of Surgery, Comprehensive Transplant Center Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - James M. Mathew
- Department of Surgery, Comprehensive Transplant Center Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
- Simpson Querrey Institute for BioNanotechnology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Joseph R. Leventhal
- Department of Surgery, Comprehensive Transplant Center Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
- Simpson Querrey Institute for BioNanotechnology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
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7
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Duneton C, Winterberg PD, Ford ML. Activation and regulation of alloreactive T cell immunity in solid organ transplantation. Nat Rev Nephrol 2022; 18:663-676. [PMID: 35902775 PMCID: PMC9968399 DOI: 10.1038/s41581-022-00600-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/23/2022] [Indexed: 01/18/2023]
Abstract
Transplantation is the only curative treatment for patients with kidney failure but it poses unique immunological challenges that must be overcome to prevent allograft rejection and ensure long-term graft survival. Alloreactive T cells are important contributors to graft rejection, and a clearer understanding of the mechanisms by which these cells recognize donor antigens - through direct, indirect or semi-direct pathways - will facilitate their therapeutic targeting. Post-T cell priming rejection responses can also be modified by targeting pathways that regulate T cell trafficking, survival cytokines or innate immune activation. Moreover, the quantity and quality of donor-reactive memory T cells crucially shape alloimmune responses. Of note, many fundamental concepts in transplant immunology have been derived from models of infection. However, the programmed differentiation of allograft-specific T cell responses is probably distinct from that of pathogen-elicited responses, owing to the dearth of pathogen-derived innate immune activation in the transplantation setting. Understanding the fundamental (and potentially unique) immunological pathways that lead to allograft rejection is therefore a prerequisite for the rational development of therapeutics that promote transplantation tolerance.
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Affiliation(s)
- Charlotte Duneton
- Paediatric Nephrology, Robert Debré Hospital, Paris, France
- Emory Transplant Center, Emory University School of Medicine, Atlanta, GA, USA
| | - Pamela D Winterberg
- Paediatric Nephrology, Emory University Department of Paediatrics and Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Mandy L Ford
- Emory Transplant Center, Emory University School of Medicine, Atlanta, GA, USA.
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8
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Betjes MGH, Peereboom ETM, Otten HG, Spierings E. The number of donor HLA-derived T cell epitopes available for indirect antigen presentation determines the risk for vascular rejection after kidney transplantation. Front Immunol 2022; 13:973968. [PMID: 36110856 PMCID: PMC9468767 DOI: 10.3389/fimmu.2022.973968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 08/15/2022] [Indexed: 11/13/2022] Open
Abstract
The role of the indirect T-cell recognition pathway of allorecognition in acute T cell-mediated rejection (aTCMR) is not well defined. The amount of theoretical T-cell epitopes available for indirect allorecognition can be quantified for donor-recipient combinations by the Predicted Indirectly ReCognizable HLA Epitopes algorithm (PIRCHE-II). The PIRCHE-II score was calculated for 688 donor kidney-recipient combinations and associated with the incidence of first-time diagnosed cases of TCMR. A diagnosis of TCMR was made in 182 cases; 121 cases of tubulo-interstitial rejection cases (79 cases of borderline TCMR, 42 cases of TCMR IA-B) and 61 cases of vascular TCMR (TCMR II-III). The PIRCHE-II score for donor HLA-DR/DQ (PIRCHE-II DR/DQ) was highly associated with vascular rejection. At one year after transplantation, the cumulative percentage of recipients with a vascular rejection was 12.7%, 8.6% and 2.1% within respectively the high, medium and low tertile of the PIRCHE-II DR/DQ score (p<0.001). In a multivariate regression analysis this association remained significant (p<0.001 for PIRCHE-II DR/DQ tertiles). The impact of a high PIRCHE-II DR/DQ score was mitigated by older recipient age and a living donor kidney. In conclusion, indirect antigen presentation of donor HLA-peptides may significantly contribute to the risk for acute vascular rejection.
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Affiliation(s)
- Michiel G. H. Betjes
- Department of Internal Medicine, Section of Nephrology and Transplantation, Erasmus Medical Center (MC), University Medical Center, Rotterdam, Netherlands
- *Correspondence: Michiel G. H. Betjes,
| | - Emma T. M. Peereboom
- Center for Translational Immunology, University Medical Center, Utrecht, Netherlands
| | - Henny G. Otten
- Center for Translational Immunology, University Medical Center, Utrecht, Netherlands
| | - Eric Spierings
- Center for Translational Immunology, University Medical Center, Utrecht, Netherlands
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9
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Ravindranath MH, El Hilali F, Filippone EJ. The Impact of Inflammation on the Immune Responses to Transplantation: Tolerance or Rejection? Front Immunol 2021; 12:667834. [PMID: 34880853 PMCID: PMC8647190 DOI: 10.3389/fimmu.2021.667834] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 10/11/2021] [Indexed: 12/21/2022] Open
Abstract
Transplantation (Tx) remains the optimal therapy for end-stage disease (ESD) of various solid organs. Although alloimmune events remain the leading cause of long-term allograft loss, many patients develop innate and adaptive immune responses leading to graft tolerance. The focus of this review is to provide an overview of selected aspects of the effects of inflammation on this delicate balance following solid organ transplantation. Initially, we discuss the inflammatory mediators detectable in an ESD patient. Then, the specific inflammatory mediators found post-Tx are elucidated. We examine the reciprocal relationship between donor-derived passenger leukocytes (PLs) and those of the recipient, with additional emphasis on extracellular vesicles, specifically exosomes, and we examine their role in determining the balance between tolerance and rejection. The concept of recipient antigen-presenting cell "cross-dressing" by donor exosomes is detailed. Immunological consequences of the changes undergone by cell surface antigens, including HLA molecules in donor and host immune cells activated by proinflammatory cytokines, are examined. Inflammation-mediated donor endothelial cell (EC) activation is discussed along with the effect of donor-recipient EC chimerism. Finally, as an example of a specific inflammatory mediator, a detailed analysis is provided on the dynamic role of Interleukin-6 (IL-6) and its receptor post-Tx, especially given the potential for therapeutic interdiction of this axis with monoclonal antibodies. We aim to provide a holistic as well as a reductionist perspective of the inflammation-impacted immune events that precede and follow Tx. The objective is to differentiate tolerogenic inflammation from that enhancing rejection, for potential therapeutic modifications. (Words 247).
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Affiliation(s)
- Mepur H. Ravindranath
- Department of Hematology and Oncology, Children’s Hospital, Los Angeles, CA, United States
- Terasaki Foundation Laboratory, Santa Monica, CA, United States
| | | | - Edward J. Filippone
- Division of Nephrology, Department of Medicine, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA, United States
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10
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Samojlik MM, Stabler CL. Designing biomaterials for the modulation of allogeneic and autoimmune responses to cellular implants in Type 1 Diabetes. Acta Biomater 2021; 133:87-101. [PMID: 34102338 PMCID: PMC9148663 DOI: 10.1016/j.actbio.2021.05.039] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 05/05/2021] [Accepted: 05/20/2021] [Indexed: 12/15/2022]
Abstract
The effective suppression of adaptive immune responses is essential for the success of allogeneic cell therapies. In islet transplantation for Type 1 Diabetes, pre-existing autoimmunity provides an additional hurdle, as memory autoimmune T cells mediate both an autoantigen-specific attack on the donor beta cells and an alloantigen-specific attack on the donor graft cells. Immunosuppressive agents used for islet transplantation are generally successful in suppressing alloimmune responses, but dramatically hinder the widespread adoption of this therapeutic approach and fail to control memory T cell populations, which leaves the graft vulnerable to destruction. In this review, we highlight the capacity of biomaterials to provide local and nuanced instruction to suppress or alter immune pathways activated in response to an allogeneic islet transplant. Biomaterial immunoisolation is a common approach employed to block direct antigen recognition and downstream cell-mediated graft destruction; however, immunoisolation alone still permits shed donor antigens to escape into the host environment, resulting in indirect antigen recognition, immune cell activation, and the creation of a toxic graft site. Designing materials to decrease antigen escape, improve cell viability, and increase material compatibility are all approaches that can decrease the local release of antigen and danger signals into the implant microenvironment. Implant materials can be further enhanced through the local delivery of anti-inflammatory, suppressive, chemotactic, and/or tolerogenic agents, which serve to control both the innate and adaptive immune responses to the implant with a benefit of reduced systemic effects. Lessons learned from understanding how to manipulate allogeneic and autogenic immune responses to pancreatic islets can also be applied to other cell therapies to improve their efficacy and duration. STATEMENT OF SIGNIFICANCE: This review explores key immunologic concepts and critical pathways mediating graft rejection in Type 1 Diabetes, which can instruct the future purposeful design of immunomodulatory biomaterials for cell therapy. A summary of immunological pathways initiated following cellular implantation, as well as current systemic immunomodulatory agents used, is provided. We then outline the potential of biomaterials to modulate these responses. The capacity of polymeric encapsulation to block some powerful rejection pathways is covered. We also highlight the role of cellular health and biocompatibility in mitigating immune responses. Finally, we review the use of bioactive materials to proactively modulate local immune responses, focusing on key concepts of anti-inflammatory, suppressive, and tolerogenic agents.
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Affiliation(s)
- Magdalena M Samojlik
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - Cherie L Stabler
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA; University of Florida Diabetes Institute, Gainesville, FL, USA; Graduate Program in Biomedical Sciences, College of Medicine, University of Florida, Gainesville, FL, USA.
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11
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Hennessy C, Lewik G, Cross A, Hester J, Issa F. Recent advances in our understanding of the allograft response. Fac Rev 2021; 10:21. [PMID: 33718938 PMCID: PMC7946390 DOI: 10.12703/r/10-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Organ transplantation is a life-saving treatment for end-stage organ failure. However, despite advances in immunosuppression, donor matching, tissue typing, and organ preservation, many organs are still lost each year to rejection. Ultimately, tolerance in the absence of immunosuppression is the goal, and although this seldom occurs spontaneously, a deeper understanding of alloimmunity may provide avenues for future therapies which aid in its establishment. Here, we highlight the recent key advances in our understanding of the allograft response. On the innate side, recent work has highlighted the previously unrecognised role of innate lymphoid cells as well as natural killer cells in promoting the alloresponse. The two major routes of allorecognition have recently been joined by a third newly identified pathway, semi-direct allorecognition, which is proving to be a key active pathway in transplantation. Through this review, we detail these newly defined areas in the allograft response and highlight areas for potential future therapeutic intervention.
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Affiliation(s)
- Conor Hennessy
- Transplantation Research Immunology Group, Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK
| | - Guido Lewik
- Transplantation Research Immunology Group, Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK
| | - Amy Cross
- Transplantation Research Immunology Group, Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK
| | - Joanna Hester
- Transplantation Research Immunology Group, Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK
| | - Fadi Issa
- Transplantation Research Immunology Group, Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK
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12
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Ronca V, Wootton G, Milani C, Cain O. The Immunological Basis of Liver Allograft Rejection. Front Immunol 2020; 11:2155. [PMID: 32983177 PMCID: PMC7492390 DOI: 10.3389/fimmu.2020.02155] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 08/07/2020] [Indexed: 12/15/2022] Open
Abstract
Liver allograft rejection remains a significant cause of morbidity and graft failure in liver transplant recipients. Rejection is caused by the recognition of non-self donor alloantigens by recipient T-cells. Antigen recognition results in proliferation and activation of T-cells in lymphoid tissue before migration to the allograft. Activated T-cells have a variety of effector mechanisms including direct T-cell mediated damage to bile ducts, endothelium and hepatocytes and indirect effects through cytokine production and recruitment of tissue-destructive inflammatory cells. These effects explain the histological appearances of typical acute T-cell mediated rejection. In addition, donor specific antibodies, most typically against HLA antigens, may give rise to antibody-mediated rejection causing damage to the allograft primarily through endothelial injury. However, as an immune-privileged site there are several mechanisms in the liver capable of overcoming rejection and promoting tolerance to the graft, particularly in the context of recruitment of regulatory T-cells and promotors of an immunosuppressive environment. Indeed, around 20% of transplant recipients can be successfully weaned from immunosuppression. Hence, the host immunological response to the liver allograft is best regarded as a balance between rejection-promoting and tolerance-promoting factors. Understanding this balance provides insight into potential mechanisms for novel anti-rejection therapies.
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Affiliation(s)
- Vincenzo Ronca
- Division of Gastroenterology and Centre for Autoimmune Liver Diseases, Department of Medicine and Surgery, University of Milan Bicocca, Milan, Italy.,National Institute of Health Research Liver Biomedical Research Unit Birmingham, Centre for Liver Research, Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom.,Liver Unit, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Grace Wootton
- National Institute of Health Research Liver Biomedical Research Unit Birmingham, Centre for Liver Research, Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | - Chiara Milani
- Division of Gastroenterology and Centre for Autoimmune Liver Diseases, Department of Medicine and Surgery, University of Milan Bicocca, Milan, Italy
| | - Owen Cain
- Department of Cellular Pathology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
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13
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Keshavarz Shahbaz S, Foroughi F, Soltaninezhad E, Jamialahmadi T, Penson PE, Sahebkar A. Application of PLGA nano/microparticle delivery systems for immunomodulation and prevention of allotransplant rejection. Expert Opin Drug Deliv 2020; 17:767-780. [PMID: 32223341 DOI: 10.1080/17425247.2020.1748006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Allograft transplantation is an effective end-point therapy to replace the function of an impaired organ. The main problem associated with allotransplantation is the induction of immune responses that results in acute and chronic graft rejection. To modulate the response of the immune system, transplant recipients generally take high dose immunosuppressant drugs for life. These drugs are associated with serious side effects such as infection with opportunistic pathogens and the development of neoplasia. AREAS COVERED We reviewed the obstacles to successful transplantation and PLGA-based strategies to reduce immune-mediated allograft rejection. EXPERT OPINION Biomaterial-based approaches using micro- and nanoparticles such as poly (lactic-co-glycolic acid) (PLGA) can be used to achieve controlled release of drugs. This approach decreases the required effective dose of drugs and enables local delivery of these agents to specific tissues and cells, whilst decreasing systemic effects.
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Affiliation(s)
- Sanaz Keshavarz Shahbaz
- Department of Immunology, School of Medicine, Mashhad University of Medical Sciences , Mashhad, Iran
| | - Farshad Foroughi
- Cellular and Molecular Research Center, Qazvin University of Medical Sciences , Qazvin, Iran
| | - Ehsan Soltaninezhad
- Department of Immunology, Faculty of Medical Science, Tarbiat Modares University , Tehran, Iran
| | - Tannaz Jamialahmadi
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences , Mashhad, Iran.,Department of Nutrition, Mashhad University of Medical Sciences , Mashhad, Iran
| | - Peter E Penson
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University , Liverpool, UK
| | - Amirhossein Sahebkar
- Halal Research Center of IRI, FDA , Tehran, Iran.,Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences , Mashhad, Iran.,School of Pharmacy, Mashhad University of Medical Sciences , Mashhad, Iran
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14
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Lei H, Reinke P, Volk HD, Lv Y, Wu R. Mechanisms of Immune Tolerance in Liver Transplantation-Crosstalk Between Alloreactive T Cells and Liver Cells With Therapeutic Prospects. Front Immunol 2019; 10:2667. [PMID: 31803188 PMCID: PMC6877506 DOI: 10.3389/fimmu.2019.02667] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/28/2019] [Indexed: 12/11/2022] Open
Abstract
Liver transplantation (LTx) is currently the most powerful treatment for end-stage liver disease. Although liver allograft is more tolerogenic compared to other solid organs, the majority of LTx recipients still require long-term immune suppression (IS) to control the undesired alloimmune responses, which can lead to severe side effects. Thus, understanding the mechanism of liver transplant tolerance and crosstalk between immune cells, especially alloreactive T cells and liver cells, can shed light on more specific tolerance induction strategies for future clinical translation. In this review, we focus on alloreactive T cell mediated immune responses and their crosstalk with liver sinusoidal endothelial cells (LSECs), hepatocytes, hepatic stellate cells (HSCs), and cholangiocytes in transplant setting. Liver cells mainly serve as antigen presenting cells (APCs) to T cells, but with low expression of co-stimulatory molecules. Crosstalk between them largely depends on the different expression of adhesion molecules and chemokine receptors. Inflammatory cytokines secreted by immune cells further elaborate this crosstalk and regulate the fate of naïve T cells differentiation within the liver graft. On the other hand, regulatory T cells (Tregs) play an essential role in inducing and keeping immune tolerance in LTx. Tregs based adoptive cell therapy provides an excellent therapeutic option for clinical transplant tolerance induction. However, many questions regarding cell therapy still need to be solved. Here we also address the current clinical trials of adoptive Tregs therapy and other tolerance induction strategies in LTx, together with future challenges for clinical translation from bench to bedside.
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Affiliation(s)
- Hong Lei
- National Local Joint Engineering Research Center for Precision Surgery and Regenerative Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.,Berlin Institute of Health Center for Regenerative Therapies, Charité University Medicine Berlin, Berlin, Germany
| | - Petra Reinke
- Berlin Institute of Health Center for Regenerative Therapies, Charité University Medicine Berlin, Berlin, Germany.,Berlin Center of Advanced Therapies, Berlin, Germany
| | - Hans-Dieter Volk
- Berlin Institute of Health Center for Regenerative Therapies, Charité University Medicine Berlin, Berlin, Germany.,Institute of Medical Immunology, Charité University Medicine Berlin, Berlin, Germany
| | - Yi Lv
- National Local Joint Engineering Research Center for Precision Surgery and Regenerative Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Rongqian Wu
- National Local Joint Engineering Research Center for Precision Surgery and Regenerative Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
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Abstract
PURPOSE OF REVIEW This article reviews recent literature on the nature of extracellular vesicles released by allogeneic transplants and examine their role in T-cell alloimmunity involved in rejection and tolerance of these grafts. RECENT FINDINGS Donor cells release extracellular vesicles, including exosomes, after transplantation of allogeneic organs and tissues. Consequently, recipient APCs take up these exosomes and present donor MHC antigens on their surface (allo-MHC cross-dressing) thus, activating some alloreactive T cells via a mechanism called semi-direct pathway of allorecognition. In addition, one study shows that exosomes carrying noninherited maternal antigens are associated with maternal microchimerism and tolerance in offspring. Finally, a few studies describe potential utilization of exosomes as modulators of alloimmunity and biomarkers of rejection in allotransplantation. SUMMARY Extracellular vesicles, including exosomes, released by allografts contribute to recognition of donor antigens by T cells after allotransplantation. This occurs through cross-dressing of recipient APCs with donor MHC antigens and subsequent activation of T cells, a process called semi-direct alloreactivity. The relevance of this phenomenon in rejection and tolerance of allografts and the potential utilization of exosomes as biomarkers in transplantation are discussed.
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16
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Longoni A, Knežević L, Schepers K, Weinans H, Rosenberg AJWP, Gawlitta D. The impact of immune response on endochondral bone regeneration. NPJ Regen Med 2018; 3:22. [PMID: 30510772 PMCID: PMC6265275 DOI: 10.1038/s41536-018-0060-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 10/26/2018] [Indexed: 12/29/2022] Open
Abstract
Tissue engineered cartilage substitutes, which induce the process of endochondral ossification, represent a regenerative strategy for bone defect healing. Such constructs typically consist of multipotent mesenchymal stromal cells (MSCs) forming a cartilage template in vitro, which can be implanted to stimulate bone formation in vivo. The use of MSCs of allogeneic origin could potentially improve the clinical utility of the tissue engineered cartilage constructs in three ways. First, ready-to-use construct availability can speed up the treatment process. Second, MSCs derived and expanded from a single donor could be applied to treat several patients and thus the costs of the medical interventions would decrease. Finally, it would allow more control over the quality of the MSC chondrogenic differentiation. However, even though the envisaged clinical use of allogeneic cell sources for bone regeneration is advantageous, their immunogenicity poses a significant obstacle to their clinical application. The aim of this review is to increase the awareness of the role played by immune cells during endochondral ossification, and in particular during regenerative strategies when the immune response is altered by the presence of implanted biomaterials and/or cells. More specifically, we focus on how this balance between immune response and bone regeneration is affected by the implantation of a cartilaginous tissue engineered construct of allogeneic origin.
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Affiliation(s)
- A Longoni
- 1Department of Oral and Maxillofacial Surgery & Special Dental Care, University Medical Center Utrecht, Utrecht University, Utrecht, G05.222, PO Box 85500, 3508 GA The Netherlands.,Regenerative Medicine Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - L Knežević
- 1Department of Oral and Maxillofacial Surgery & Special Dental Care, University Medical Center Utrecht, Utrecht University, Utrecht, G05.222, PO Box 85500, 3508 GA The Netherlands.,3Faculty of Health Sciences, University of Bristol, Biomedical Sciences Building, Bristol, BS8 1TD UK
| | - K Schepers
- 4Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, 2300RC Leiden, The Netherlands
| | - H Weinans
- 5Department of Orthopaedics, University Medical Center Utrecht, Utrecht University, 3508 GA Utrecht, The Netherlands.,6Department of Rheumatology, University Medical Center Utrecht, Utrecht University, 3584CX Utrecht, The Netherlands.,7Department of Biomechanical Engineering, Delft University of Technology, 2628CD Delft, The Netherlands
| | - A J W P Rosenberg
- 1Department of Oral and Maxillofacial Surgery & Special Dental Care, University Medical Center Utrecht, Utrecht University, Utrecht, G05.222, PO Box 85500, 3508 GA The Netherlands
| | - D Gawlitta
- 1Department of Oral and Maxillofacial Surgery & Special Dental Care, University Medical Center Utrecht, Utrecht University, Utrecht, G05.222, PO Box 85500, 3508 GA The Netherlands.,Regenerative Medicine Center Utrecht, 3584 CT Utrecht, The Netherlands
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17
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Siu JHY, Surendrakumar V, Richards JA, Pettigrew GJ. T cell Allorecognition Pathways in Solid Organ Transplantation. Front Immunol 2018; 9:2548. [PMID: 30455697 PMCID: PMC6230624 DOI: 10.3389/fimmu.2018.02548] [Citation(s) in RCA: 138] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Accepted: 10/17/2018] [Indexed: 02/02/2023] Open
Abstract
Transplantation is unusual in that T cells can recognize alloantigen by at least two distinct pathways: as intact MHC alloantigen on the surface of donor cells via the direct pathway; and as self-restricted processed alloantigen via the indirect pathway. Direct pathway responses are viewed as strong but short-lived and hence responsible for acute rejection, whereas indirect pathway responses are typically thought to be much longer lasting and mediate the progression of chronic rejection. However, this is based on surprisingly scant experimental evidence, and the recent demonstration that MHC alloantigen can be re-presented intact on recipient dendritic cells-the semi-direct pathway-suggests that the conventional view may be an oversimplification. We review recent advances in our understanding of how the different T cell allorecognition pathways are triggered, consider how this generates effector alloantibody and cytotoxic CD8 T cell alloresponses and assess how these responses contribute to early and late allograft rejection. We further discuss how this knowledge may inform development of cellular and pharmacological therapies that aim to improve transplant outcomes, with focus on the use of induced regulatory T cells with indirect allospecificity and on the development of immunometabolic strategies. KEY POINTS Acute allograft rejection is likely mediated by indirect and direct pathway CD4 T cell alloresponses.Chronic allograft rejection is largely mediated by indirect pathway CD4 T cell responses. Direct pathway recognition of cross-dressed endothelial derived MHC class II alloantigen may also contribute to chronic rejection, but the extent of this contribution is unknown.Late indirect pathway CD4 T cell responses will be composed of heterogeneous populations of allopeptide specific T helper cell subsets that recognize different alloantigens and are at various stages of effector and memory differentiation.Knowledge of the precise indirect pathway CD4 T cell responses active at late time points in a particular individual will likely inform the development of alloantigen-specific cellular therapies and will guide immunometabolic modulation.
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18
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Extracellular vesicle-mediated MHC cross-dressing in immune homeostasis, transplantation, infectious diseases, and cancer. Semin Immunopathol 2018; 40:477-490. [PMID: 29594331 DOI: 10.1007/s00281-018-0679-8] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 03/16/2018] [Indexed: 12/19/2022]
Abstract
Eukaryotic cells employ different types of extracellular vesicles (EVs) to exchange proteins, mRNAs, non-coding regulatory RNAs, carbohydrates, and lipids. Cells of the immune system, in particular antigen (Ag)-presenting cells (APCs), acquire major histocompatibility complex (MHC) class I and II molecules loaded with antigenic peptides from leukocytes and tissue parenchymal and stromal cells, through a mechanism known as MHC cross-dressing. Increasing evidence indicates that cross-dressing of APCs with pre-formed Ag-peptide/MHC complexes (pMHCs) is mediated via passage of clusters of EVs with characteristics of exosomes. A percentage of the transferred EVs remain attached to the acceptor APCs, with the appropriate orientation, at sufficient concentration within localized areas of the plasma membrane, and for sufficient time, so the preformed pMHCs carried by the EVs are presented without further processing, to cognate T cells. Although its biological relevance is not fully understood, numerous studies have demonstrated that MHC cross-dressing of APCs represents a pathway of Ag presentation of acquired pre-formed pMHCs to T cells-alternative to direct and cross-presentation-participate in immune homeostasis and T cell tolerance, cross-regulate alloreactive T cells with different MHC restricted specificities, and is a mechanism of Ag spreading for autologous, allogeneic, microbial, tumor, or vaccine-delivered Ags. Here, we compare MHC cross-dressing with other mechanisms and terminologies used for pMHC transfer, including trogocytosis. We discuss the experimental evidence, mostly from in vitro and ex vivo studies, of the role of MHC cross-dressing of APCs via EVs in positive or negative regulation of T cell immunity in the steady state, transplantation, microbial diseases, and cancer.
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19
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Abstract
BACKGROUND The liver immune environment is tightly regulated to balance immune activation with immune tolerance. Understanding the dominant immune pathways initiated in the liver is important because the liver is a site for cell transplantation, such as for islet and hepatocyte transplantation. The purpose of this study is to examine the consequences of alloimmune stimulation when allogeneic cells are transplanted to the liver in comparison to a different immune locale, such as the kidney. METHODS We investigated cellular and humoral immune responses when allogeneic hepatocytes are transplanted directly to the recipient liver by intraportal injection. A heterotopic kidney engraftment site was used for comparison to immune activation in the liver microenvironment. RESULTS Transplantation of allogeneic hepatocytes delivered directly to the liver, via recipient portal circulation, stimulated long-term, high magnitude CD8 T cell-mediated allocytotoxicity. CD8 T cells initiated significant in vivo allocytotoxicity as well as rapid rejection of hepatocytes transplanted to the liver even in the absence of secondary lymph nodes or CD4 T cells. In contrast, in the absence of recipient peripheral lymphoid tissue and CD4 T cells, CD8-mediated in vivo allocytotoxicity was abrogated, and rejection was delayed when hepatocellular allografts were transplanted to the kidney subcapsular site. CONCLUSIONS These results highlight the CD8-dominant proinflammatory immune responses unique to the liver microenvironment. Allogeneic cells transplanted directly to the liver do not enjoy immune privilege but rather require immunosuppression to prevent rejection by a robust and persistent CD8-dependent allocytotoxicity primed in the liver.
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20
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Morelli AE, Bracamonte-Baran W, Burlingham WJ. Donor-derived exosomes: the trick behind the semidirect pathway of allorecognition. Curr Opin Organ Transplant 2017; 22:46-54. [PMID: 27898464 PMCID: PMC5407007 DOI: 10.1097/mot.0000000000000372] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE OF REVIEW The passenger leukocyte hypothesis predicts that after transplantation, donor antigen-presenting cells (APCs) from the graft present donor MHC molecules to directly alloreactive T cells in lymphoid organs. However, in certain transplantation models, recent evidence contradicts this long-standing concept. New findings demonstrate that host, instead of donor, APCs play a prominent role in allosensitization against donor MHC molecules via the semidirect pathway. A similar mechanism operates in development of T-cell split tolerance to noninherited maternal antigens. RECENT FINDINGS Following fully mismatch skin or heart transplantation in mice, no or extremely few donor migrating APCs (i.e. conventional dendritic cells) are detected in the draining lymphoid organs. Instead, recipient dendritic cells that have captured donor extracellular vesicles (i.e. exosomes) carrying donor MHC molecules and APC costimulatory signals present donor MHC molecules to directly alloreactive T cells. This semidirect pathway can also give rise to a form of 'split' tolerance during chronic alloantigen exposure, as indirectly alloreactive T helper cells and directly alloreactive T-cell effectors are differentially impacted by host dendritic cells 'cross-dressed' with extracellular vesicles/exosomes derived from maternal microchimerism. SUMMARY Acquisition by recipient APCs of donor exosomes (and likely other extracellular vesicles) released by passenger leukocytes or the graft explains the potent T-cell allosensitization against donor MHC molecules, in the absence or presence of few passenger leukocytes in lymphoid organs. It also provides the basic mechanism and in-vivo relevance of the elusive semidirect pathway. Its degree of coordination with the allopeptide - specific, indirect pathway of T-cell help may determine whether semidirect allopresentation results in a sustained, effective, acute rejection response, or rather, in abortive acute rejection and 'split' tolerance.
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Affiliation(s)
- Adrian E Morelli
- aT.E. Starzl Transplantation Institute, Department of Surgery and Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania bDivision of Immunology, Department of Pathology, Johns Hopkins University, Baltimore, Maryland cDivision of Transplantation, Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin, USA
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21
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Smyth LA, Lechler RI, Lombardi G. Continuous Acquisition of MHC:Peptide Complexes by Recipient Cells Contributes to the Generation of Anti-Graft CD8 + T Cell Immunity. Am J Transplant 2017; 17:60-68. [PMID: 27495898 PMCID: PMC5213774 DOI: 10.1111/ajt.13996] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 07/26/2016] [Accepted: 07/26/2016] [Indexed: 01/25/2023]
Abstract
Understanding the evolution of the direct and indirect pathways of allorecognition following tissue transplantation is essential in the design of tolerance-promoting protocols. On the basis that donor bone marrow-derived antigen-presenting cells are eliminated within days of transplantation, it has been argued that the indirect response represents the major threat to long-term transplant survival, and is consequently the key target for regulation. However, the detection of MHC transfer between cells, and particularly the capture of MHC:peptide complexes by dendritic cells (DCs), led us to propose a third, semidirect, pathway of MHC allorecognition. Persistence of this pathway would lead to sustained activation of direct-pathway T cells, arguably persisting for the life of the transplant. In this study, we focused on the contribution of acquired MHC-class I on recipient DCs during the life span of a skin graft. We observed that MHC-class I acquisition by recipient DCs occurs for at least 1 month following transplantation and may be the main source of alloantigen that drives CD8+ cytotoxic T cell responses. In addition, acquired MHC-class I:peptide complexes stimulate T cell responses in vivo, further emphasizing the need to regulate both pathways to induce indefinite survival of the graft.
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Affiliation(s)
- L. A. Smyth
- Medical Research Council (MRC) Centre for TransplantationKing's College LondonLondonUK,National Institute for Health Research (NIHR) Comprehensive Biomedical Research CentreGuy's and St. Thomas’ NHS Foundation Trust and King's College LondonLondonUK,School of Health, Sport and BioscienceUniversity of East LondonLondonUK
| | - R. I. Lechler
- Medical Research Council (MRC) Centre for TransplantationKing's College LondonLondonUK,National Institute for Health Research (NIHR) Comprehensive Biomedical Research CentreGuy's and St. Thomas’ NHS Foundation Trust and King's College LondonLondonUK
| | - G. Lombardi
- Medical Research Council (MRC) Centre for TransplantationKing's College LondonLondonUK,National Institute for Health Research (NIHR) Comprehensive Biomedical Research CentreGuy's and St. Thomas’ NHS Foundation Trust and King's College LondonLondonUK
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22
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Alegre ML, Lakkis FG, Morelli AE. Antigen Presentation in Transplantation. Trends Immunol 2016; 37:831-843. [PMID: 27743777 DOI: 10.1016/j.it.2016.09.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 09/12/2016] [Accepted: 09/15/2016] [Indexed: 02/07/2023]
Abstract
Transplantation of solid organs between genetically distinct individuals leads, in the absence of immunosuppression, to T cell-dependent transplant rejection. Activation of graft-reactive T cells relies on the presentation of transplant-derived antigens (intact donor MHC molecules or processed peptides on host MHC molecules) by mature dendritic cells (DCs). This review focuses on novel insights regarding the steps for maturation and differentiation of DCs that are necessary for productive presentation of transplant antigens to host T cells. These steps include the licensing of DCs by the microbiota, their activation and maturation following recognition of allogeneic non-self, and their capture of donor cell exosomes to amplify the presentation of transplant antigens.
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Affiliation(s)
- Maria-Luisa Alegre
- Department of Medicine, University of Chicago, 924 East 57th Street, JFK-R312, Chicago, IL 60637, USA.
| | - Fadi G Lakkis
- Thomas E. Starzl Transplantation Institute and Departments of Surgery and Immunology, University of Pittsburgh School of Medicine, Biomedical Science Tower, 200 Lothrop Street, Pittsburgh, PA 15261, USA; Thomas E. Starzl Transplantation Institute and Department of Medicine, University of Pittsburgh School of Medicine, Biomedical Science Tower, 200 Lothrop Street, Pittsburgh, PA 15261, USA
| | - Adrian E Morelli
- Thomas E. Starzl Transplantation Institute and Departments of Surgery and Immunology, University of Pittsburgh School of Medicine, Biomedical Science Tower, 200 Lothrop Street, Pittsburgh, PA 15261, USA
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23
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Abstract
Direct allorecognition is the process by which donor-derived major histocompatibility complex (MHC)-peptide complexes, typically presented by donor-derived ‘passenger’ dendritic cells, are recognised directly by recipient T cells. In this review, we discuss the two principle theories which have been proposed to explain why individuals possess a high-precursor frequency of T cells with direct allospecificity and how self-restricted T cells recognise allogeneic MHC-peptide complexes. These theories, both of which are supported by functional and structural data, suggest that T cells recognising allogeneic MHC-peptide complexes focus either on the allopeptides bound to the allo-MHC molecules or the allo-MHC molecules themselves. We discuss how direct alloimmune responses may be sustained long term, the consequences of this for graft outcome and highlight novel strategies which are currently being investigated as a potential means of reducing rejection mediated through this pathway.
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Affiliation(s)
- Dominic A Boardman
- MRC Centre for Transplantation, King's College London, Guy's Hospital, London, SE1 9RT UK ; NIHR Biomedical Research Centre, Guy's & St Thomas' NHS Foundation Trust & King's College London, Guy's Hospital, London, SE1 9RT UK
| | - Jacinta Jacob
- MRC Centre for Transplantation, King's College London, Guy's Hospital, London, SE1 9RT UK
| | - Lesley A Smyth
- MRC Centre for Transplantation, King's College London, Guy's Hospital, London, SE1 9RT UK ; School of Health, Sport and Bioscience, Stratford Campus, University of East London, London, E15 4LZ UK
| | - Giovanna Lombardi
- MRC Centre for Transplantation, King's College London, Guy's Hospital, London, SE1 9RT UK ; NIHR Biomedical Research Centre, Guy's & St Thomas' NHS Foundation Trust & King's College London, Guy's Hospital, London, SE1 9RT UK
| | - Robert I Lechler
- MRC Centre for Transplantation, King's College London, Guy's Hospital, London, SE1 9RT UK ; NIHR Biomedical Research Centre, Guy's & St Thomas' NHS Foundation Trust & King's College London, Guy's Hospital, London, SE1 9RT UK
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Liu Q, Rojas-Canales DM, Divito SJ, Shufesky WJ, Stolz DB, Erdos G, Sullivan MLG, Gibson GA, Watkins SC, Larregina AT, Morelli AE. Donor dendritic cell-derived exosomes promote allograft-targeting immune response. J Clin Invest 2016; 126:2805-20. [PMID: 27348586 DOI: 10.1172/jci84577] [Citation(s) in RCA: 220] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 05/04/2016] [Indexed: 12/11/2022] Open
Abstract
The immune response against transplanted allografts is one of the most potent reactions mounted by the immune system. The acute rejection response has been attributed to donor dendritic cells (DCs), which migrate to recipient lymphoid tissues and directly activate alloreactive T cells against donor MHC molecules. Here, using a murine heart transplant model, we determined that only a small number of donor DCs reach lymphoid tissues and investigated how this limited population of donor DCs efficiently initiates the alloreactive T cell response that causes acute rejection. In our mouse model, efficient passage of donor MHC molecules to recipient conventional DCs (cDCs) was dependent on the transfer of extracellular vesicles (EVs) from donor DCs that migrated from the graft to lymphoid tissues. These EVs shared characteristics with exosomes and were internalized or remained attached to the recipient cDCs. Recipient cDCs that acquired exosomes became activated and triggered full activation of alloreactive T cells. Depletion of recipient cDCs after cardiac transplantation drastically decreased presentation of donor MHC molecules to directly alloreactive T cells and delayed graft rejection in mice. These findings support a key role for transfer of donor EVs in the generation of allograft-targeting immune responses and suggest that interrupting this process has potential to dampen the immune response to allografts.
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25
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CD8 T-cell recognition of acquired alloantigen promotes acute allograft rejection. Proc Natl Acad Sci U S A 2015; 112:12788-93. [PMID: 26420874 DOI: 10.1073/pnas.1513533112] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Adaptive CD8 T-cell immunity is the principal arm of the cellular alloimmune response, but its development requires help. This can be provided by CD4 T cells that recognize alloantigen "indirectly," as self-restricted allopeptide, but this process remains unexplained, because the target epitopes for CD4 and CD8 T-cell recognition are "unlinked" on different cells (recipient and donor antigen presenting cells (APCs), respectively). Here, we test the hypothesis that the presentation of intact and processed MHC class I alloantigen by recipient dendritic cells (DCs) (the "semidirect" pathway) allows linked help to be delivered by indirect-pathway CD4 T cells for generating destructive cytotoxic CD8 T-cell alloresponses. We show that CD8 T-cell-mediated rejection of murine heart allografts that lack hematopoietic APCs requires host secondary lymphoid tissue (SLT). SLT is necessary because within it, recipient dendritic cells can acquire MHC from graft parenchymal cells and simultaneously present it as intact protein to alloreactive CD8 T cells and as processed peptide alloantigen for recognition by indirect-pathway CD4 T cells. This enables delivery of essential help for generating cytotoxic CD8 T-cell responses that cause rapid allograft rejection. In demonstrating the functional relevance of the semidirect pathway to transplant rejection, our findings provide a solution to a long-standing conundrum as to why SLT is required for CD8 T-cell allorecognition of graft parenchymal cells and suggest a mechanism by which indirect-pathway CD4 T cells provide help for generating effector cytotoxic CD8 T-cell alloresponses at late time points after transplantation.
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26
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27
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Abstract
With the advent of cellular therapies, it has become clear that the success of future therapies in prolonging allograft survival will require an intimate understanding of the allorecognition pathways and effector mechanisms that are responsible for chronic rejection and late graft loss.Here, we consider current understanding of T-cell allorecognition pathways and discuss the most likely mechanisms by which these pathways collaborate with other effector mechanisms to cause allograft rejection. We also consider how this knowledge may inform development of future strategies to prevent allograft rejection.Although both direct and indirect pathway CD4 T cells appear active immediately after transplantation, it has emerged that indirect pathway CD4 T cells are likely to be the dominant alloreactive T-cell population late after transplantation. Their ability to provide help for generating long-lived alloantibody is likely one of the main mechanisms responsible for the progression of allograft vasculopathy and chronic rejection.Recent work has suggested that regulatory T cells may be an effective cellular therapy in transplantation. Given the above, adoptive therapy with CD4 regulatory T cells with indirect allospecificity is a rational first choice in attempting to attenuate the development and progression of chronic rejection; those with additional properties that enable inhibition of germinal center alloantibody responses hold particular appeal.
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28
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Ruiz P, Maldonado P, Hidalgo Y, Gleisner A, Sauma D, Silva C, Saez JJ, Nuñez S, Rosemblatt M, Bono MR. Transplant tolerance: new insights and strategies for long-term allograft acceptance. Clin Dev Immunol 2013; 2013:210506. [PMID: 23762087 PMCID: PMC3665173 DOI: 10.1155/2013/210506] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 04/12/2013] [Accepted: 04/13/2013] [Indexed: 02/08/2023]
Abstract
One of the greatest advances in medicine during the past century is the introduction of organ transplantation. This therapeutic strategy designed to treat organ failure and organ dysfunction allows to prolong the survival of many patients that are faced with no other treatment option. Today, organ transplantation between genetically dissimilar individuals (allogeneic grafting) is a procedure widely used as a therapeutic alternative in cases of organ failure, hematological disease treatment, and some malignancies. Despite the potential of organ transplantation, the administration of immunosuppressive drugs required for allograft acceptance induces severe immunosuppression in transplanted patients, which leads to serious side effects such as infection with opportunistic pathogens and the occurrence of neoplasias, in addition to the known intrinsic toxicity of these drugs. To solve this setback in allotransplantation, researchers have focused on manipulating the immune response in order to create a state of tolerance rather than unspecific immunosuppression. Here, we describe the different treatments and some of the novel immunotherapeutic strategies undertaken to induce transplantation tolerance.
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Affiliation(s)
- Paulina Ruiz
- Departamento de Biologia, Facultad de Ciencias, Universidad de Chile, 7800024 Santiago, Chile
- Programa de Ciencias Biomedicas, Facultad de Medicina, Universidad de Chile, 8380453 Santiago, Chile
| | - Paula Maldonado
- Departamento de Biologia, Facultad de Ciencias, Universidad de Chile, 7800024 Santiago, Chile
| | - Yessia Hidalgo
- Departamento de Biologia, Facultad de Ciencias, Universidad de Chile, 7800024 Santiago, Chile
| | - Alejandra Gleisner
- Departamento de Biologia, Facultad de Ciencias, Universidad de Chile, 7800024 Santiago, Chile
| | - Daniela Sauma
- Departamento de Biologia, Facultad de Ciencias, Universidad de Chile, 7800024 Santiago, Chile
- Fundacion Ciencia y Vida, 7780272 Santiago, Chile
| | - Cinthia Silva
- Departamento de Biologia, Facultad de Ciencias, Universidad de Chile, 7800024 Santiago, Chile
| | - Juan Jose Saez
- Departamento de Biologia, Facultad de Ciencias, Universidad de Chile, 7800024 Santiago, Chile
| | - Sarah Nuñez
- Departamento de Biologia, Facultad de Ciencias, Universidad de Chile, 7800024 Santiago, Chile
| | - Mario Rosemblatt
- Departamento de Biologia, Facultad de Ciencias, Universidad de Chile, 7800024 Santiago, Chile
- Fundacion Ciencia y Vida, 7780272 Santiago, Chile
- Facultad de Ciencias Biologicas, Universidad Andres Bello, 8370146 Santiago, Chile
| | - Maria Rosa Bono
- Departamento de Biologia, Facultad de Ciencias, Universidad de Chile, 7800024 Santiago, Chile
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29
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Sivaganesh S, Harper SJ, Conlon TM, Callaghan CJ, Saeb-Parsy K, Negus MC, Motallebzadeh R, Bolton EM, Bradley JA, Pettigrew GJ. Copresentation of intact and processed MHC alloantigen by recipient dendritic cells enables delivery of linked help to alloreactive CD8 T cells by indirect-pathway CD4 T cells. THE JOURNAL OF IMMUNOLOGY 2013; 190:5829-38. [PMID: 23630361 DOI: 10.4049/jimmunol.1300458] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In transplantation, direct-pathway CD8 T cells that recognize alloantigen on donor cells require CD4 help for activation and cytolytic function. The ability of indirect-pathway CD4 T cells to provide this help remains unexplained, because a fundamental requirement for epitope linkage is seemingly broken. The simultaneous presentation, by host dendritic cells (DCs), of both intact MHC class I alloantigen and processed alloantigen would deliver linked help, but has not been demonstrated definitively. In this study, we report that following in vitro coculture with BALB/c DCs, small numbers (~1.5%) of C57BL/6 (B6) DCs presented acquired H-2(d) alloantigen both as processed allopeptide and as unprocessed Ag. This represented class I alloantigen provides a conformational epitope for direct-pathway allorecognition, because B6 DCs isolated from cocultures and transferred to naive B6 mice provoked cytotoxic CD8 T cell alloimmunity. Crucially, this response was dependent upon simultaneous presentation of class II-restricted allopeptide, because despite acquiring similar amounts of H-2(d) alloantigen upon coculture, MHC class II-deficient B6 DCs failed to elicit cytotoxic alloimmunity. The relevance of this pathway to solid-organ transplantation was then confirmed by the demonstration that CD8 T cell cytotoxicity was provoked in secondary recipients by transfer of DCs purified from wild-type, but not from MHC class II-deficient, C57BL/6 recipients of BALB/c heart transplants. These experiments demonstrate that representation of conformationally intact MHC alloantigen by recipient APC can induce cytotoxic alloimmunity, but simultaneous copresentation of processed allopeptide is essential, presumably because this facilitates linked recognition by indirect-pathway CD4 Th cells.
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Affiliation(s)
- Siva Sivaganesh
- Department of Surgery, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
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Sagoo P, Lombardi G, Lechler RI. Relevance of regulatory T cell promotion of donor-specific tolerance in solid organ transplantation. Front Immunol 2012; 3:184. [PMID: 22811678 PMCID: PMC3395995 DOI: 10.3389/fimmu.2012.00184] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 06/14/2012] [Indexed: 01/29/2023] Open
Abstract
Current clinical strategies to control the alloimmune response after transplantation do not fully prevent induction of the immunological processes which lead to acute and chronic immune-mediated graft rejection, and as such the survival of a solid organ allograft is limited. Experimental research on naturally occurring CD4+CD25highFoxP3+ Regulatory T cells (Tregs) has indicated their potential to establish stable long-term graft acceptance, with the promise of providing a more effective therapy for transplant recipients. Current approaches for clinical use are based on the infusion of freshly isolated or ex vivo polyclonally expanded Tregs into graft recipients with an aim to redress the in vivo balance of T effector cells to Tregs. However mounting evidence suggests that regulation of donor-specific immunity may be central to achieving immunological tolerance. Therefore, the next stages in optimizing translation of Tregs to organ transplantation will be through the refinement and development of donor alloantigen-specific Treg therapy. The altering kinetics and intensity of alloantigen presentation pathways and alloimmune priming following transplantation may indeed influence the specificity of the Treg required and the timing or frequency at which it needs to be administered. Here we review and discuss the relevance of antigen-specific regulation of alloreactivity by Tregs in experimental and clinical studies of tolerance and explore the concept of delivering an optimal Treg for the induction and maintenance phases of achieving transplantation tolerance.
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Affiliation(s)
- Pervinder Sagoo
- Department Transplantation, Immunoregulation and Mucosal Biology, MRC Centre for Transplantation, King's College London London, UK
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