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Khan MA, Shamma T. Complement factor and T-cell interactions during alloimmune inflammation in transplantation. J Leukoc Biol 2018; 105:681-694. [PMID: 30536904 DOI: 10.1002/jlb.5ru0718-288r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 10/25/2018] [Accepted: 11/21/2018] [Indexed: 02/06/2023] Open
Abstract
Complement factor and T-cell signaling during an effective alloimmune response plays a key role in transplant-associated injury, which leads to the progression of chronic rejection (CR). During an alloimmune response, activated complement factors (C3a and C5a) bind to their corresponding receptors (C3aR and C5aR) on a number of lymphocytes, including T-regulatory cells (Tregs), and these cell-molecular interactions have been vital to modulate an effective immune response to/from Th1-effector cell and Treg activities, which result in massive inflammation, microvascular impairments, and fibrotic remodeling. Involvement of the complement-mediated cell signaling during transplantation signifies a crucial role of complement components as a key therapeutic switch to regulate ongoing inflammatory state, and further to avoid the progression of CR of the transplanted organ. This review highlights the role of complement-T cell interactions, and how these interactions shunt the effector immune response during alloimmune inflammation in transplantation, which could be a novel therapeutic tool to protect a transplanted organ and avoid progression of CR.
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Affiliation(s)
- Mohammad Afzal Khan
- Organ Transplant Research Section, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - Talal Shamma
- Organ Transplant Research Section, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
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52
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Gour N, Smole U, Yong HM, Lewkowich IP, Yao N, Singh A, Gabrielson E, Wills-Karp M, Lajoie S. C3a is required for ILC2 function in allergic airway inflammation. Mucosal Immunol 2018; 11:1653-1662. [PMID: 30104625 PMCID: PMC6279480 DOI: 10.1038/s41385-018-0064-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 06/23/2018] [Indexed: 02/04/2023]
Abstract
Aberrant type 2 responses underlie the pathologies in allergic diseases like asthma, yet, our understanding of the mechanisms that drive them remains limited. Recent evidence suggests that dysregulated innate immune factors can perpetuate asthma pathogenesis. In susceptible individuals, allergen exposure triggers the activation of complement, a major arm of innate immunity, leading to the aberrant generation of the C3a anaphylatoxin. C3 and C3a have been shown to be important for the development of Th2 responses, yet remarkably, the mechanisms by which C3a regulates type 2 immunity are relatively unknown. We demonstrate a central role for C3a in driving type 2 innate lymphoid cells (ILC2)-mediated inflammation in response to allergen and IL-33. Our data suggests that ILC2 recruitment is C3a-dependent. Further, we show that ILC2s directly respond to C3a, promoting type 2 responses by specifically: (1) inducing IL-13 and granulocyte-macrophage colony-stimulating factor, whereas inhibiting IL-10 production from ILC2; and (2) enhancing their antigen-presenting capability during ILC-T-cell cross-talk. In summary, we identify a novel mechanism by which C3a can mediate aberrant type 2 responses to aeroallergen exposure, which involves a yet unrecognized cross-talk between two major innate immune components-complement and group 2 innate lymphoid cells.
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Affiliation(s)
- Naina Gour
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD,Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD
| | - Ursula Smole
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD,Institute of Immunology, Center for Pathophysiology, Infectiology, and Immunology, Medical University of Vienna, Vienna, Austria
| | - Hwan-Mee Yong
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - Ian P. Lewkowich
- Department of Immunobiology, Cincinnati Childrens Hospital Medical Center, Cincinnati, OH
| | - Nu Yao
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - Anju Singh
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - Edward Gabrielson
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Marsha Wills-Karp
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - Stephane Lajoie
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
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53
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Arens K, Filippis C, Kleinfelder H, Goetzee A, Reichmann G, Crauwels P, Waibler Z, Bagola K, van Zandbergen G. Anti-Tumor Necrosis Factor α Therapeutics Differentially Affect Leishmania Infection of Human Macrophages. Front Immunol 2018; 9:1772. [PMID: 30108591 PMCID: PMC6079256 DOI: 10.3389/fimmu.2018.01772] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 07/17/2018] [Indexed: 01/18/2023] Open
Abstract
Tumor necrosis factor α (TNFα) drives the pathophysiology of human autoimmune diseases and consequently, neutralizing antibodies (Abs) or Ab-derived molecules directed against TNFα are essential therapeutics. As treatment with several TNFα blockers has been reported to entail a higher risk of infectious diseases such as leishmaniasis, we established an in vitro model based on Leishmania-infected human macrophages, co-cultured with autologous T-cells, for the analysis and comparison of anti-TNFα therapeutics. We demonstrate that neutralization of soluble TNFα (sTNFα) by the anti-TNFα Abs Humira®, Remicade®, and its biosimilar Remsima® negatively affects infection as treatment with these agents significantly reduces Leishmania-induced T-cell proliferation and increases the number of infected macrophages. By contrast, we show that blockade of sTNFα by Cimzia® does not affect T-cell proliferation and infection rates. Moreover, compared to Remicade®, treatment with Cimzia® does not impair the expression of cytolytic effector proteins in proliferating T-cells. Our data demonstrate that Cimzia® supports parasite control through its conjugated polyethylene glycol (PEG) moiety as PEGylation of Remicade® improves the clearance of intracellular Leishmania. This effect can be linked to complement activation, with levels of complement component C5a being increased upon treatment with Cimzia® or a PEGylated form of Remicade®. Taken together, we provide an in vitro model of human leishmaniasis that allows direct comparison of different anti-TNFα agents. Our results enhance the understanding of the efficacy and adverse effects of TNFα blockers and they contribute to evaluate anti-TNFα therapy for patients living in countries with a high prevalence of leishmaniasis.
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Affiliation(s)
- Katharina Arens
- Division of Immunology, Paul-Ehrlich-Institut, Langen, Germany
| | | | | | - Arthur Goetzee
- Division of Immunology, Paul-Ehrlich-Institut, Langen, Germany
| | | | - Peter Crauwels
- Division of Immunology, Paul-Ehrlich-Institut, Langen, Germany
| | - Zoe Waibler
- Division of Immunology, Paul-Ehrlich-Institut, Langen, Germany
| | - Katrin Bagola
- Division of Immunology, Paul-Ehrlich-Institut, Langen, Germany
| | - Ger van Zandbergen
- Division of Immunology, Paul-Ehrlich-Institut, Langen, Germany.,Institute of Immunology, Johannes Gutenberg University, Mainz, Germany
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54
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Khan MA, Alanazi F, Ahmed HA, Vater A, Assiri AM, Broering DC. C5a Blockade Increases Regulatory T Cell Numbers and Protects Against Microvascular Loss and Epithelial Damage in Mouse Airway Allografts. Front Immunol 2018; 9:1010. [PMID: 29881374 PMCID: PMC5976734 DOI: 10.3389/fimmu.2018.01010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 04/23/2018] [Indexed: 12/15/2022] Open
Abstract
Microvascular injury during acute rejection has been associated with massive infiltration of CD4+ T effector cells, and the formation of complement products (C3a and C5a). Regulatory T cells (Tregs) are potent immunosuppressors of the adaptive immune system and have proven sufficient to rescue microvascular impairments. Targeting C5a has been linked with improved microvascular recovery, but its effects on the Treg and T effector balance is less well known. Here, we demonstrate the impact of C5a blockade on Treg induction and microvascular restoration in rejecting mouse airway allografts. BALB/c→C57BL/6 allografts were treated with a C5a-neutralizing l-aptamer (10 mg/kg, i.p. at d0 and every second day thereafter), and allografts were serially monitored for Treg infiltration, tissue oxygenation (tpO2), microvascular blood flow, and functional microvasculature between donor and recipients during allograft rejection. We demonstrated that C5a blocking significantly leads to enhanced presence of Tregs in the allograft, reinstates donor-recipient functional microvasculature, improves tpO2, microvascular blood flow, and epithelial repair, followed by an upregulation of IL-5, TGF-β, IL-10 vascular endothelial growth factor, and ANGPT1 gene expression, while it maintained a healthy epithelium and prevented subepithelial collagen deposition at d28 posttransplantation. Together, these data indicate that inhibition of C5a signaling has potential to preserve microvasculature and rescue allograft from a sustained hypoxic/ischemic phase, limits airway tissue remodeling through the induction of Treg-mediated immune tolerance. These findings may be useful in designing anti-C5a therapy in combination with existing immunosuppressive regimens to rescue tissue/organ rejection.
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Affiliation(s)
- Mohammad Afzal Khan
- Comparative Medicine Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
- Organ Transplant Centre, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Fatimah Alanazi
- Comparative Medicine Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
- Organ Transplant Centre, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Hala Abdalrahman Ahmed
- Comparative Medicine Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | | | - Abdullah Mohammed Assiri
- Comparative Medicine Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
- College of Medicine, AlFaisal University, Riyadh, Saudi Arabia
- Institute for Research and Medical Consultations, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Dieter Clemens Broering
- Organ Transplant Centre, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
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Fribourg M, Ni J, Papavasiliou FN, Yue Z, Heeger PS, Leventhal JS. Allospecific Memory B Cell Responses Are Dependent on Autophagy. Am J Transplant 2018; 18:102-112. [PMID: 28621910 PMCID: PMC5732898 DOI: 10.1111/ajt.14394] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 06/07/2017] [Accepted: 06/08/2017] [Indexed: 01/25/2023]
Abstract
Long-lived, donor-reactive memory B cells (Bmems) can produce alloantibodies that mediate transplant injury. Autophagy, an intrinsic mechanism of cell organelle/component recycling, is required for Bmem survival in infectious and model antigen systems, but whether autophagy affects alloreactive Bmem is unknown. We studied mice with an inducible yellow fluorescent protein (YFP) reporter expressed under the activation-induced cytidine deaminase (AID) promoter active in B cells undergoing germinal center reactions. Up to 12 months after allogeneic sensitization, splenic YFP+ B cells were predominantly IgD- IgM- IgG+ and expressed CD73, CD80, and PD-L2, consistent with Bmems. Labeled cells contained significantly more cells with autophagosomes and more autophagosomes per cell than unlabeled, naïve B cells. To test for a functional link, we quantified alloantibody formation in mice with B cells conditionally deficient in the requisite autophagy gene ATG7. These experiments revealed absent B cell ATG7 (1) prevented B cell autophagy, (2) inhibited secondary alloantibody responses without altering primary alloantibody formation, and (3) diminished frequencies of alloreactive Bmems. Pharmacological autophagy inhibition with 3-methyladenine had similar effects on wild-type mice. Together with new documentation of increased autophagosomes within human Bmems, our data indicate that targeting autophagy has potential for eliminating donor-reactive Bmems in transplant recipients.
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Affiliation(s)
- Miguel Fribourg
- Department of Neurology and Center for Translational Systems Biology, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Jie Ni
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, USA
| | - F. Nina Papavasiliou
- Department of Immunology, Virology, and Microbiology, The Rockefeller University, New York, USA
| | - Zhenyu Yue
- Department of Neurology, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Peter S. Heeger
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, USA,Transplant Research Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Jeremy S. Leventhal
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, USA,Transplant Research Institute, Icahn School of Medicine at Mount Sinai, New York, USA,Renal Division, James J Peters Bronx VA Medical Center, Bronx, New York, USA
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56
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Fisher AJ, Cipolla E, Varre A, Gu H, Mickler EA, Vittal R. Potential Mechanisms Underlying TGF-β-mediated Complement Activation in Lung Fibrosis. ACTA ACUST UNITED AC 2017; 3. [PMID: 29377033 DOI: 10.21767/2573-5365.100037] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
While our previous studies suggest that limiting bleomycin-induced complement activation suppresses TGF-β signaling, the specific hierarchical interactions between TGF-β and complement in lung fibrosis are unclear. Herein, we investigated the mechanisms underlying TGF-β-induced complement activation in the pathogenesis of lung fibrosis. C57-BL6 mice were given intratracheal instillations of adenoviral vectors overexpressing TGF-β (Ad-TGFβ) or the firefly gene-luciferase (Ad-Luc; control). Two weeks later, mice with fibrotic lungs were instilled RNAi specific to receptors for C3a or C5a-C3ar or C5ar, and sacrificed at day 28. Histopathological analyses revealed that genetic silencing of C3ar or C5ar arrested the progression of TGF-β-induced lung fibrosis, collagen deposition and content (hydroxyproline, col1a1/2); and significantly suppressed local complement activation. With genetic silencing of either C3ar or C5ar, in Ad-TGFβ-injured lungs: we detected the recovery of Smad7 (TGF-β inhibitor) and diminished local release of DAF (membrane-bound complement inhibitor); in vitro: TGF-β-mediated loss of DAF was prevented. Conversely, blockade of the TGF-β receptor prevented C3a-mediated loss of DAF in both normal primary human alveolar and small airway epithelial cells. Of the 52 miRNAs analyzed as part of the Affymetrix array, normal primary human SAECs exposed to C3a, C5a or TGF-β caused discrete and overlapping miRNA regulation related to epithelial proliferation or apoptosis (miR-891A, miR-4442, miR-548, miR-4633), cellular contractility (miR-1197) and lung fibrosis (miR-21, miR-200C, miR-31HG, miR-503). Our studies present potential mechanisms by which TGF-β activates complement and promotes lung fibrosis.
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Affiliation(s)
- Amanda J Fisher
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Ellyse Cipolla
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of Michigan, Ann Arbor, USA
| | - Ananya Varre
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of Michigan, Ann Arbor, USA
| | - Hongmei Gu
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Elizabeth A Mickler
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Ragini Vittal
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of Michigan, Ann Arbor, USA
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57
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Jane-Wit D, Fang C, Goldstein DR. Innate immune mechanisms in transplant allograft vasculopathy. Curr Opin Organ Transplant 2017; 21:253-7. [PMID: 27077602 DOI: 10.1097/mot.0000000000000314] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE OF REVIEW Allograft vasculopathy is the leading cause of late allograft loss following solid organ transplantation. Ischemia reperfusion injury and donor-specific antibody-induced complement activation confer heightened risk for allograft vasculopathy via numerous innate immune mechanisms, including MyD88, high-mobility group box 1 (HMGB1), and complement-induced noncanonical nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling. RECENT FINDINGS The role of MyD88, a signal adaptor downstream of the Toll-like receptors (TLR), has been defined in an experimental heart transplant model, which demonstrated that recipient MyD88 enhanced allograft vasculopathy. Importantly, triggering receptor on myeloid receptor 1, a MyD88 amplifying signal, was present in rejecting human cardiac transplant biopsies and enhanced the development of allograft vasculopathy in mice. HMGB1, a nuclear protein that activates Toll-like receptors, also enhanced the development of allograft vasculopathy. Complement activation elicits assembly of membrane attack complexes on endothelial cells which activate noncanonical NF-κB signaling, a novel complement effector pathway that induces proinflammatory genes and potentiates endothelial cell-mediated alloimmune T-cell activation, processes which enhance allograft vasculopathy. SUMMARY Innate immune mediators, including HMGB1, MyD88, and noncanonical NF-κB signaling via complement activation contribute to allograft vasculopathy. These pathways represent potential therapeutic targets to reduce allograft vasculopathy after solid organ transplantation.
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Affiliation(s)
- Dan Jane-Wit
- aDepartment of Cardiovascular Medicine bDepartment of Immunobiology, Yale School of Medicine, New Haven, Connecticut, USA
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58
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Abstract
PURPOSE OF REVIEW Despite considerable advances in controlling acute rejection, the longevity of cardiac and renal allografts remains significantly limited by chronic rejection in the form of allograft vasculopathy. This review discusses recently reported mechanistic insights of allograft vasculopathy pathogenesis as well as recent clinical evaluations of new therapeutic approaches. RECENT FINDINGS Although adaptive immunity is the major driver of allograft vasculopathy, natural killer cells mediate vasculopathic changes in a transplanted mouse heart following treatment with donor-specific antibody (DSA). However, natural killer cells may also dampen chronic inflammatory responses by killing donor-derived tissue-resident CD4 T cells that provide help to host B cells, the source of DSA. DSA may directly contribute to vascular inflammation by inducing intracellular signaling cascades that upregulate leukocyte adhesion molecules, facilitating recruitment of neutrophils and monocytes. DSA-mediated complement activation additionally enhances endothelial alloimmunogenicity through activation of noncanonical NF-κB signaling. New clinical studies evaluating mammalian target of rapamycin and proteasome inhibitors to target these pathways have been reported. SUMMARY Allograft vasculopathy is a disorder resulting from several innate and adaptive alloimmune responses. Mechanistic insights from preclinical studies have identified agents that are currently being investigated in clinical trials.
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Complement-Mediated Enhancement of Monocyte Adhesion to Endothelial Cells by HLA Antibodies, and Blockade by a Specific Inhibitor of the Classical Complement Cascade, TNT003. Transplantation 2017. [PMID: 28640789 PMCID: PMC5482566 DOI: 10.1097/tp.0000000000001486] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Background Antibody-mediated rejection (AMR) of most solid organs is characterized by evidence of complement activation and/or intragraft macrophages (C4d + and CD68+ biopsies). We previously demonstrated that crosslinking of HLA I by antibodies triggered endothelial activation and monocyte adhesion. We hypothesized that activation of the classical complement pathway at the endothelial cell surface by HLA antibodies would enhance monocyte adhesion through soluble split product generation, in parallel with direct endothelial activation downstream of HLA signaling. Methods Primary human aortic endothelial cells (HAEC) were stimulated with HLA class I antibodies in the presence of intact human serum complement. C3a and C5a generation, endothelial P-selectin expression, and adhesion of human primary and immortalized monocytes (Mono Mac 6) were measured. Alternatively, HAEC or monocytes were directly stimulated with purified C3a or C5a. Classical complement activation was inhibited by pretreatment of complement with an anti-C1s antibody (TNT003). Results Treatment of HAEC with HLA antibody and human complement increased the formation of C3a and C5a. Monocyte recruitment by human HLA antibodies was enhanced in the presence of intact human serum complement or purified C3a or C5a. Specific inhibition of the classical complement pathway using TNT003 or C1q-depleted serum significantly reduced adhesion of monocytes in the presence of human complement. Conclusions Despite persistent endothelial viability in the presence of HLA antibodies and complement, upstream complement anaphylatoxin production exacerbates endothelial exocytosis and leukocyte recruitment. Upstream inhibition of classical complement may be therapeutic to dampen mononuclear cell recruitment and endothelial activation characteristic of microvascular inflammation during AMR. Valenzuela et al show that HLA antibody binding to human endothelial cells in vitro, triggered complement C3a and C5a deposition that mediated monocyte recruitment, and the salutary effects of inhibiting the classical complement pathway with an anti-C1s antibody. Supplemental digital content is available in the text.
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60
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Erdei A, Sándor N, Mácsik-Valent B, Lukácsi S, Kremlitzka M, Bajtay Z. The versatile functions of complement C3-derived ligands. Immunol Rev 2017; 274:127-140. [PMID: 27782338 DOI: 10.1111/imr.12498] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The complement system is a major component of immune defense. Activation of the complement cascade by foreign substances and altered self-structures may lead to the elimination of the activating agent, and during the enzymatic cascade, several biologically active fragments are generated. Most immune regulatory effects of complement are mediated by the activation products of C3, the central component. The indispensable role of C3 in opsonic phagocytosis as well as in the regulation of humoral immune response is known for long, while the involvement of complement in T-cell biology have been revealed in the past few years. In this review, we discuss the immune modulatory functions of C3-derived fragments focusing on their role in processes which have not been summarized so far. The importance of locally synthesized complement will receive special emphasis, as several immunological processes take place in tissues, where hepatocyte-derived complement components might not be available at high concentrations. We also aim to call the attention to important differences between human and mouse systems regarding C3-mediated processes.
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Affiliation(s)
- Anna Erdei
- Department of Immunology, Eötvös Loránd University, Budapest, Hungary. , .,MTA-ELTE Immunology Research Group, Budapest, Eötvös Loránd University, Budapest, Hungary. ,
| | - Noémi Sándor
- MTA-ELTE Immunology Research Group, Budapest, Eötvös Loránd University, Budapest, Hungary
| | | | - Szilvia Lukácsi
- Department of Immunology, Eötvös Loránd University, Budapest, Hungary
| | - Mariann Kremlitzka
- MTA-ELTE Immunology Research Group, Budapest, Eötvös Loránd University, Budapest, Hungary
| | - Zsuzsa Bajtay
- Department of Immunology, Eötvös Loránd University, Budapest, Hungary
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61
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Dixon KO, O'Flynn J, Klar-Mohamad N, Daha MR, van Kooten C. Properdin and factor H production by human dendritic cells modulates their T-cell stimulatory capacity and is regulated by IFN-γ. Eur J Immunol 2017; 47:470-480. [PMID: 28105653 PMCID: PMC5363362 DOI: 10.1002/eji.201646703] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 12/16/2016] [Accepted: 01/17/2017] [Indexed: 12/12/2022]
Abstract
Dendritic cells (DCs) and complement are both key members of the innate and adaptive immune response. Recent experimental mouse models have shown that production of alternative pathway (AP) components by DCs strongly affects their ability to activate and regulate T-cell responses. In this study we investigated the production and regulation of properdin (fP) and factor H (fH) both integral regulators of the AP, by DCs and tolerogenic DCs (tolDCs). Both fP and fH were produced by DCs, with significantly higher levels of both AP components produced by tolDCs. Upon activation with IFN-γ both cells increased fH production, while simultaneously decreasing production of fP. IL-27, a member of the IL-12 family, increased fH, but production of fP remained unaffected. The functional capacity of fP and fH produced by DCs and tolDCs was confirmed by their ability to bind C3b. Inhibition of fH production by DCs resulted in a greater ability to induce allogenic CD4+ T-cell proliferation. In contrast, inhibition of fP production led to a significantly reduced allostimulatory capacity. In summary, this study shows that production of fP and fH by DCs, differentially regulates their immunogenicity, and that the local cytokine environment can profoundly affect the production of fP and fH.
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Affiliation(s)
- Karen O Dixon
- Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands.,Evergrande Center for Immunologic Diseases at Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
| | - Joseph O'Flynn
- Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ngaisah Klar-Mohamad
- Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands
| | - Mohamed R Daha
- Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands
| | - Cees van Kooten
- Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands
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62
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Quell KM, Karsten CM, Kordowski A, Almeida LN, Briukhovetska D, Wiese AV, Sun J, Ender F, Antoniou K, Schröder T, Schmudde I, Berger JL, König P, Vollbrandt T, Laumonnier Y, Köhl J. Monitoring C3aR Expression Using a Floxed tdTomato-C3aR Reporter Knock-in Mouse. THE JOURNAL OF IMMUNOLOGY 2017. [PMID: 28626064 DOI: 10.4049/jimmunol.1700318] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
C3a exerts multiple biologic functions through activation of its cognate C3a receptor. C3-/- and C3aR-/- mice have been instrumental in defining important roles of the C3a/C3aR axis in the regulation of acute and chronic inflammatory diseases, including ischemia/reperfusion injury, allergic asthma, autoimmune nephritis, and rheumatoid arthritis. Surprisingly little is known about C3aR expression and function in immune and stromal cells. To close this gap, we generated a floxed tandem-dye Tomato (tdTomato)-C3aR reporter knock-in mouse, which we used to monitor C3aR expression in cells residing in the lung, airways, lamina propria (LP) of the small intestine, brain, visceral adipose tissue, bone marrow (BM), spleen, and the circulation. We found a strong expression of tdTomato-C3aR in the brain, lung, LP, and visceral adipose tissue, whereas it was minor in the spleen, blood, BM, and the airways. Most macrophage and eosinophil populations were tdTomato-C3aR+ Interestingly, most tissue eosinophils and some macrophage populations expressed C3aR intracellularly. BM-derived dendritic cells (DCs), lung-resident cluster of differentiation (CD) 11b+ conventional DCs (cDCs) and monocyte-derived DCs, LP CD103+, and CD11b+ cDCs but not pulmonary CD103+ cDCs and splenic DCs were tdTomato-C3aR+ Surprisingly, neither BM, blood, lung neutrophils, nor mast cells expressed C3aR. Similarly, all lymphoid-derived cells were tdTomato-C3aR-, except some LP-derived type 3 innate lymphoid cells. Pulmonary and LP-derived epithelial cells expressed at best minor levels of C3aR. In summary, we provide novel insights into the expression pattern of C3aR in mice. The floxed C3aR knock-in mouse will help to reliably track and conditionally delete C3aR expression in experimental models of inflammation.
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Affiliation(s)
- Katharina M Quell
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Christian M Karsten
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Anna Kordowski
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | | | - Daria Briukhovetska
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Anna V Wiese
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Jing Sun
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Fanny Ender
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Konstantina Antoniou
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Torsten Schröder
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Inken Schmudde
- Institute of Anatomy, University of Lübeck, Lübeck 23562, Germany
| | - Johann L Berger
- Institute of Anatomy, University of Lübeck, Lübeck 23562, Germany
| | - Peter König
- Institute of Anatomy, University of Lübeck, Lübeck 23562, Germany
| | - Tillman Vollbrandt
- Cell Analysis Core Facility, University of Lübeck, Lübeck 23562, Germany; and
| | - Yves Laumonnier
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany;
| | - Jörg Köhl
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany; .,Division of Immunobiology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH 45229
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63
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Cernoch M, Viklicky O. Complement in Kidney Transplantation. Front Med (Lausanne) 2017; 4:66. [PMID: 28611987 PMCID: PMC5447724 DOI: 10.3389/fmed.2017.00066] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 05/09/2017] [Indexed: 12/12/2022] Open
Abstract
The complement system is considered to be an important part of innate immune system with a significant role in inflammation processes. The activation can occur through classical, alternative, or lectin pathway, resulting in the creation of anaphylatoxins C3a and C5a, possessing a vast spectrum of immune functions, and the assembly of terminal complement cascade, capable of direct cell lysis. The activation processes are tightly regulated; inappropriate activation of the complement cascade plays a significant role in many renal diseases including organ transplantation. Moreover, complement cascade is activated during ischemia/reperfusion injury processes and influences delayed graft function of kidney allografts. Interestingly, complement system has been found to play a role in both acute cellular and antibody-mediated rejections and thrombotic microangiopathy. Therefore, complement system may represent an interesting therapeutical target in kidney transplant pathologies.
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Affiliation(s)
- Marek Cernoch
- Transplant Laboratory, Transplant Center, Institute for Clinical and Experimental Medicine, Prague, Czechia
| | - Ondrej Viklicky
- Transplant Laboratory, Transplant Center, Institute for Clinical and Experimental Medicine, Prague, Czechia.,Department of Nephrology, Transplant Center, Institute for Clinical and Experimental Medicine, Prague, Czechia
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64
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Sheen JH, Strainic MG, Liu J, Zhang W, Yi Z, Medof ME, Heeger PS. TLR-Induced Murine Dendritic Cell (DC) Activation Requires DC-Intrinsic Complement. THE JOURNAL OF IMMUNOLOGY 2017; 199:278-291. [PMID: 28539427 DOI: 10.4049/jimmunol.1700339] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/04/2017] [Indexed: 01/04/2023]
Abstract
Induction of proinflammatory T cell immunity is augmented by innate dendritic cell (DC) maturation commonly initiated by TLR signaling. We demonstrate that ligation of TLR3, TLR4, and TLR9 induces murine DC production of complement components and local production of the anaphylatoxin C5a. In vitro, ex vivo, and in vivo analyses show that TLR-induced DC maturation, as assessed by surface phenotype, expression profiling by gene array, and functional ability to stimulate T cell responses, requires autocrine C3a receptor and C5a receptor (C3ar1/C5ar1) signaling. Studies using bone marrow chimeric animals and Foxp3-GFP/ERT2-Cre/dTomato fate-mapping mice show that TLR-initiated DC autocrine C3ar1/C5ar1 signaling causes expansion of effector T cells and instability of regulatory T cells and contributes to T cell-dependent transplant rejection. Together, our data position immune cell-derived complement production and autocrine/paracrine C3ar1/C5ar1 signaling as crucial intermediary processes that link TLR stimulation to DC maturation and the subsequent development of effector T cell responses.
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Affiliation(s)
- Joong-Hyuk Sheen
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Translational Transplant Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Precision Institute of Immunology, Icahn School of Medicine at Mount Sinai, New York, NY 10029; and
| | - Michael G Strainic
- Institute of Pathology, Case Western Reserve University, Cleveland, OH 44106
| | - Jinbo Liu
- Institute of Pathology, Case Western Reserve University, Cleveland, OH 44106
| | - Weijia Zhang
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Translational Transplant Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Zhengzi Yi
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Translational Transplant Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - M Edward Medof
- Institute of Pathology, Case Western Reserve University, Cleveland, OH 44106
| | - Peter S Heeger
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029; .,Translational Transplant Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Precision Institute of Immunology, Icahn School of Medicine at Mount Sinai, New York, NY 10029; and
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65
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Lubbers R, van Essen MF, van Kooten C, Trouw LA. Production of complement components by cells of the immune system. Clin Exp Immunol 2017; 188:183-194. [PMID: 28249350 DOI: 10.1111/cei.12952] [Citation(s) in RCA: 302] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2017] [Indexed: 12/14/2022] Open
Abstract
The complement system is an important part of the innate immune defence. It contributes not only to local inflammation, removal and killing of pathogens, but it also assists in shaping of the adaptive immune response. Besides a role in inflammation, complement is also involved in physiological processes such as waste disposal and developmental programmes. The complement system comprises several soluble and membrane-bound proteins. The bulk of the soluble proteins is produced mainly by the liver. While several complement proteins are produced by a wide variety of cell types, other complement proteins are produced by only a few related cell types. As these data suggest that local production by specific cell types may have specific functions, more detailed studies have been employed recently analysing the local and even intracellular role of these complement proteins. Here we review the current knowledge about extrahepatic production and/or secretion of complement components. More specifically, we address what is known about complement synthesis by cells of the human immune system.
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Affiliation(s)
- R Lubbers
- Department of Rheumatology, Leiden University Medical Center, Leiden, the Netherlands
| | - M F van Essen
- Department of Nephrology, Leiden University Medical Center, Leiden, the Netherlands
| | - C van Kooten
- Department of Nephrology, Leiden University Medical Center, Leiden, the Netherlands
| | - L A Trouw
- Department of Rheumatology, Leiden University Medical Center, Leiden, the Netherlands
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66
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Not All Antibodies Are Created Equal: Factors That Influence Antibody Mediated Rejection. J Immunol Res 2017; 2017:7903471. [PMID: 28373996 PMCID: PMC5360970 DOI: 10.1155/2017/7903471] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 02/17/2017] [Accepted: 02/23/2017] [Indexed: 12/13/2022] Open
Abstract
Consistent with Dr. Paul Terasaki's "humoral theory of rejection" numerous studies have shown that HLA antibodies can cause acute and chronic antibody mediated rejection (AMR) and decreased graft survival. New evidence also supports a role for antibodies to non-HLA antigens in AMR and allograft injury. Despite the remarkable efforts by leaders in the field who pioneered single antigen bead technology for detection of donor specific antibodies, a considerable amount of work is still needed to better define the antibody attributes that are associated with AMR pathology. This review highlights what is currently known about the clinical context of pre and posttransplant antibodies, antibody characteristics that influence AMR, and the paths after donor specific antibody production (no rejection, subclinical rejection, and clinical dysfunction with AMR).
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67
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Khan MA. T regulatory cell mediated immunotherapy for solid organ transplantation: A clinical perspective. Mol Med 2017; 22:892-904. [PMID: 27878210 PMCID: PMC5319206 DOI: 10.2119/molmed.2016.00050] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 11/11/2016] [Indexed: 12/12/2022] Open
Abstract
T regulatory cells (Tregs) play a vital role in suppressing heightened immune responses, and thereby promote a state of immunological tolerance. Tregs modulate both innate and adaptive immunity, which make them a potential candidate for cell-based immunotherapy to suppress uncontrolled activation of graft specific inflammatory cells and their toxic mediators. These grafts specific inflammatory cells (T effector cells) and other inflammatory mediators (Immunoglobulins, active complement mediators) are mainly responsible for graft vascular deterioration followed by acute/chronic rejection. Treg mediated immunotherapy is under investigation to induce allospecific tolerance in various ongoing clinical trials in organ transplant recipients. Treg immunotherapy is showing promising results but the key issues regarding Treg immunotherapy are not yet fully resolved including their mechanism of action, and specific Treg cell phenotype responsible for a state of tolerance. This review highlights the involvement of various subsets of Tregs during immune suppression, novelty of Tregs functions, effects on angiogenesis, emerging technologies for effective Treg expansion, plasticity and safety associated with clinical applications. Altogether this information will assist in designing single/combined Treg mediated therapies for successful clinical trials in solid organ transplantations.
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Affiliation(s)
- Mohammad Afzal Khan
- Comparative Medicine Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia 11211
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68
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Khan MA, Alanazi F, Ahmed HA, Al-Mohanna FH, Assiri AM, Broering DC. FOXP3 + regulatory T cell ameliorates microvasculature in the rejection of mouse orthotopic tracheal transplants. Clin Immunol 2016; 174:84-98. [PMID: 27939405 DOI: 10.1016/j.clim.2016.11.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 10/23/2016] [Accepted: 11/20/2016] [Indexed: 12/18/2022]
Abstract
Microvascular loss may be a root cause of chronic rejection in lung transplants, which leads to the bronchiolitis obliterans syndrome. Previous research implicates T regulatory cell (Treg) as a key component of immune modulation, however, Treg has never been examined as a reparative mediator to salvage microvasculature during transplantation. Here, we reconstituted purified Tregs in to allografts, and serially monitored allografts for tissue oxygenation, microvascular perfusion for four weeks. We demonstrated that Tregs reconstitution of allografts significantly improve tissue oxygenation, microvascular flow, epithelial repair, number of CD4+CD25highFOXP3+ Tregs, followed by an upregulation of proinflammatory, angiogenic and regulatory genes, while prevented subepithelial deposition of CD4+T cells at d10, and collagen at d28 post-transplantation. Altogether, these findings concluded that Treg-mediated immunotherapy has potential to preserve microvasculature and rescue allograft from sustained hypoxic/ischemic phase, limits airway tissue remodeling, and therefore may be a useful therapeutic tool to prevent chronic rejection after organ transplantation.
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Affiliation(s)
- Mohammad Afzal Khan
- Organ Transplant Research Section, Comparative Medicine Department, King Faisal Specialist Hospital and Research Centre, MBC 03, P.O. Box 3354, Riyadh 11211, Saudi Arabia.
| | - Fatimah Alanazi
- Organ Transplant Research Section, Comparative Medicine Department, King Faisal Specialist Hospital and Research Centre, MBC 03, P.O. Box 3354, Riyadh 11211, Saudi Arabia.
| | - Hala Abdalrahman Ahmed
- Comparative Medicine Department, King Faisal Specialist Hospital and Research Centre, MBC 03, P.O. Box 3354, Riyadh 11211, Saudi Arabia.
| | - Falah Hassan Al-Mohanna
- Comparative Medicine Department, King Faisal Specialist Hospital and Research Centre, MBC 03, P.O. Box 3354, Riyadh 11211, Saudi Arabia.
| | - Abdullah Mohammed Assiri
- Comparative Medicine Department, King Faisal Specialist Hospital and Research Centre, MBC 03, P.O. Box 3354, Riyadh 11211, Saudi Arabia.
| | - Dieter Clemens Broering
- Organ Transplant Research Section, Comparative Medicine Department, King Faisal Specialist Hospital and Research Centre, MBC 03, P.O. Box 3354, Riyadh 11211, Saudi Arabia.
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69
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Blurring the Lines Between Innate and Adaptive Immunity. Transplantation 2016; 100:1789-1790. [PMID: 27542068 DOI: 10.1097/tp.0000000000001429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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70
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Montero RM, Sacks SH, Smith RA. Complement-here, there and everywhere, but what about the transplanted organ? Semin Immunol 2016; 28:250-9. [PMID: 27179705 DOI: 10.1016/j.smim.2016.04.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 04/20/2016] [Accepted: 04/26/2016] [Indexed: 12/15/2022]
Abstract
The part of the innate immune system that communicates and effectively primes the adaptive immune system was termed "complement" by Ehrlich to reflect its complementarity to antibodies having previously been described as "alexine" (i.e protective component of serum) by Buchner and Bordet. It has been established that complement is not solely produced systemically but may have origin in different tissues where it can influence organ specific functions that may affect the outcome of transplanted organs. This review looks at the role of complement in particular to kidney transplantation. We look at current literature to determine whether blockade of the peripheral or central compartments of complement production may prevent ischaemic reperfusion injury or rejection in the transplanted organ. We also review new therapeutics that have been developed to inhibit components of the complement cascade with varying degrees of success leading to an increase in our understanding of the multiple triggers of this complex system. In addition, we consider whether biomarkers in this field are effective markers of disease or treatment.
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Affiliation(s)
- R M Montero
- MRC Centre for Transplantation, Division of Transplant Immunology and Mucosal Biology, NIHR Comprehensive Biomedical Research Centre, King's College London, Guy's & St Thomas' NHS Foundation Trust, United Kingdom
| | - S H Sacks
- MRC Centre for Transplantation, Division of Transplant Immunology and Mucosal Biology, NIHR Comprehensive Biomedical Research Centre, King's College London, Guy's & St Thomas' NHS Foundation Trust, United Kingdom.
| | - R A Smith
- MRC Centre for Transplantation, Division of Transplant Immunology and Mucosal Biology, NIHR Comprehensive Biomedical Research Centre, King's College London, Guy's & St Thomas' NHS Foundation Trust, United Kingdom
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71
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Fung A, Zhao H, Yang B, Lian Q, Ma D. Ischaemic and inflammatory injury in renal graft from brain death donation: an update review. J Anesth 2016; 30:307-16. [DOI: 10.1007/s00540-015-2120-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 12/08/2015] [Indexed: 12/20/2022]
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72
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Khan MA, Hsu JL, Assiri AM, Broering DC. Targeted complement inhibition and microvasculature in transplants: a therapeutic perspective. Clin Exp Immunol 2015; 183:175-86. [PMID: 26404106 DOI: 10.1111/cei.12713] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/17/2015] [Indexed: 12/18/2022] Open
Abstract
Active complement mediators play a key role in graft-versus-host diseases, but little attention has been given to the angiogenic balance and complement modulation during allograft acceptance. The complement cascade releases the powerful proinflammatory mediators C3a and C5a anaphylatoxins, C3b, C5b opsonins and terminal membrane attack complex into tissues, which are deleterious if unchecked. Blocking complement mediators has been considered to be a promising approach in the modern drug discovery plan, and a significant number of therapeutic alternatives have been developed to dampen complement activation and protect host cells. Numerous immune cells, especially macrophages, develop both anaphylatoxin and opsonin receptors on their cell surface and their binding affects the macrophage phenotype and their angiogenic properties. This review discusses the mechanism that complement contributes to angiogenic injury, and the development of future therapeutic targets by antagonizing activated complement mediators to preserve microvasculature in rejecting the transplanted organ.
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Affiliation(s)
- M A Khan
- Organ Transplant Centre, Comparative Medicine Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - J L Hsu
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - A M Assiri
- Organ Transplant Centre, Comparative Medicine Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - D C Broering
- Organ Transplant Centre, Comparative Medicine Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
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73
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Abstract
PURPOSE OF REVIEW To summarize the current knowledge regarding mechanisms linking the complement system to transplant injury, highlighting findings reported since 2013. RECENT FINDINGS Building upon the documentation that complement activation is a pathogenic mediator of posttransplant ischemia-reperfusion injury, emerging evidence from animal models indicates that blocking either the classical or lectin pathways attenuates ischemia-reperfusion injury. Immune cell-derived and locally activated complement, including intracellular C3, positively modulates alloreactive T-cell activation and expansion, whereby simultaneously inhibiting regulatory T-cell induction and function, and together promoting transplant rejection. Although alloantibody-initiated complement activation directly injures target cells, complement-dependent signals activate endothelial cells to facilitate T-cell-dependent inflammation. Complement activation within allografts contributes to progressive chronic injury and fibrosis. SUMMARY The complement cascade, traditionally considered to be relevant to transplantation only as an effector mechanism of antibody-initiated allograft injury, is now understood to damage the allograft through multiple mechanisms. Complement activation promotes posttransplant ischemia-reperfusion injury, formation and function of alloantibody, differentiation and function of alloreactive T cells, and contributes to chronic progressive allograft failure. The recognition that complement affects transplant injury at many levels provides a foundation for targeting complement as a therapy to prolong transplant survival and improve patient health.
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74
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Zhang L, Bell BA, Yu M, Chan CC, Peachey NS, Fung J, Zhang X, Caspi RR, Lin F. Complement anaphylatoxin receptors C3aR and C5aR are required in the pathogenesis of experimental autoimmune uveitis. J Leukoc Biol 2015; 99:447-54. [PMID: 26394814 DOI: 10.1189/jlb.3a0415-157r] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 09/03/2015] [Indexed: 12/19/2022] Open
Abstract
Recent studies have suggested that reagents inhibiting complement activation could be effective in treating T cell mediated autoimmune diseases such as autoimmune uveitis. However, the precise role of the complement anaphylatoxin receptors (C3a and C5a receptors) in the pathogenesis of autoimmune uveitis remains elusive and controversial. We induced experimental autoimmune uveitis in mice deficient or sufficient in both C3a and C5a receptors and rigorously compared their retinal phenotype using various imaging techniques, including indirect ophthalmoscopy, confocal scanning laser ophthalmoscopy, spectral domain optical coherence tomography, topical endoscopic fundus imaging, and histopathological analysis. We also assessed retinal function using electroretinography. Moreover, we performed Ag-specific T cell recall assays and T cell adoptive transfer experiments to compare pathogenic T cell activity between wild-type and knockout mice with experimental autoimmune uveitis. These experiments showed that C3a receptor/C5a receptor-deficient mice developed much less severe uveitis than did control mice using all retinal examination methods and that these mice had reduced pathogenic T cell responses. Our data demonstrate that both complement anaphylatoxin receptors are important for the development of experimental autoimmune uveitis, suggesting that targeting these receptors could be a valid approach for treating patients with autoimmune uveitis.
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Affiliation(s)
- Lingjun Zhang
- *Eye Research Institute, Tianjin Medical University Eye Center, Tianjin, China; Department of Immunology, Lerner Research Institute, Department of Ophthalmic Research, Cole Eye Institute, and Digestive Disease Institute, Cleveland Clinic, Cleveland, Ohio, USA; and Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Brent A Bell
- *Eye Research Institute, Tianjin Medical University Eye Center, Tianjin, China; Department of Immunology, Lerner Research Institute, Department of Ophthalmic Research, Cole Eye Institute, and Digestive Disease Institute, Cleveland Clinic, Cleveland, Ohio, USA; and Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Minzhong Yu
- *Eye Research Institute, Tianjin Medical University Eye Center, Tianjin, China; Department of Immunology, Lerner Research Institute, Department of Ophthalmic Research, Cole Eye Institute, and Digestive Disease Institute, Cleveland Clinic, Cleveland, Ohio, USA; and Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Chi-Chao Chan
- *Eye Research Institute, Tianjin Medical University Eye Center, Tianjin, China; Department of Immunology, Lerner Research Institute, Department of Ophthalmic Research, Cole Eye Institute, and Digestive Disease Institute, Cleveland Clinic, Cleveland, Ohio, USA; and Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Neal S Peachey
- *Eye Research Institute, Tianjin Medical University Eye Center, Tianjin, China; Department of Immunology, Lerner Research Institute, Department of Ophthalmic Research, Cole Eye Institute, and Digestive Disease Institute, Cleveland Clinic, Cleveland, Ohio, USA; and Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - John Fung
- *Eye Research Institute, Tianjin Medical University Eye Center, Tianjin, China; Department of Immunology, Lerner Research Institute, Department of Ophthalmic Research, Cole Eye Institute, and Digestive Disease Institute, Cleveland Clinic, Cleveland, Ohio, USA; and Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Xiaoming Zhang
- *Eye Research Institute, Tianjin Medical University Eye Center, Tianjin, China; Department of Immunology, Lerner Research Institute, Department of Ophthalmic Research, Cole Eye Institute, and Digestive Disease Institute, Cleveland Clinic, Cleveland, Ohio, USA; and Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Rachel R Caspi
- *Eye Research Institute, Tianjin Medical University Eye Center, Tianjin, China; Department of Immunology, Lerner Research Institute, Department of Ophthalmic Research, Cole Eye Institute, and Digestive Disease Institute, Cleveland Clinic, Cleveland, Ohio, USA; and Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Feng Lin
- *Eye Research Institute, Tianjin Medical University Eye Center, Tianjin, China; Department of Immunology, Lerner Research Institute, Department of Ophthalmic Research, Cole Eye Institute, and Digestive Disease Institute, Cleveland Clinic, Cleveland, Ohio, USA; and Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
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75
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Thomas KA, Valenzuela NM, Gjertson D, Mulder A, Fishbein MC, Parry GC, Panicker S, Reed EF. An Anti-C1s Monoclonal, TNT003, Inhibits Complement Activation Induced by Antibodies Against HLA. Am J Transplant 2015; 15:2037-49. [PMID: 25904443 PMCID: PMC4654252 DOI: 10.1111/ajt.13273] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 02/10/2015] [Accepted: 02/17/2015] [Indexed: 01/25/2023]
Abstract
Antibody-mediated rejection (AMR) of solid organ transplants (SOT) is characterized by damage triggered by donor-specific antibodies (DSA) binding donor Class I and II HLA (HLA-I and HLA-II) expressed on endothelial cells. While F(ab')2 portions of DSA cause cellular activation and proliferation, Fc regions activate the classical complement cascade, resulting in complement deposition and leukocyte recruitment, both hallmark features of AMR. We characterized the ability of an anti-C1s monoclonal antibody, TNT003, to inhibit HLA antibody (HLA-Ab)-induced complement activation. Complement deposition induced by HLA-Ab was evaluated using novel cell- and bead-based assays. Human aortic endothelial cells (HAEC) were cultured with HLA-Ab and human complement; production of activated complement proteins was measured by flow cytometry. Additionally, C3d deposition was measured on single antigen beads (SAB) mixed with HLA-Ab and human complement. TNT003 inhibited HLA-Ab mediated complement deposition on HAEC in a concentration-dependent manner; C3a, C4a and C5a anaphylatoxin production was also diminished by TNT003. Finally, TNT003 blocked C3d deposition induced by Class I (HLAI-Ab)- and Class II (HLAII-Ab)-specific antibodies on SAB. These data suggest TNT003 may be useful for modulating the effects of DSA, as TNT003 inhibits complement deposition and split product formation generated by HLA-I/II-Ab in vitro.
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Affiliation(s)
- K A Thomas
- Department of Pathology and Laboratory Medicine, University of CaliforniaLos Angeles, CA
| | - N M Valenzuela
- Department of Pathology and Laboratory Medicine, University of CaliforniaLos Angeles, CA
| | - D Gjertson
- Department of Pathology and Laboratory Medicine, University of CaliforniaLos Angeles, CA
| | - A Mulder
- Department of Immunohematology and Blood Transfusion, Leiden University Medical CenterLeiden, the Netherlands
| | - M C Fishbein
- Department of Pathology and Laboratory Medicine, University of CaliforniaLos Angeles, CA
| | - G C Parry
- True North Therapeutics, Inc.South San Francisco, CA
| | - S Panicker
- True North Therapeutics, Inc.South San Francisco, CA
| | - E F Reed
- Department of Pathology and Laboratory Medicine, University of CaliforniaLos Angeles, CA,*Corresponding author: Elaine F. Reed,
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76
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Salvadori M, Rosso G, Bertoni E. Complement involvement in kidney diseases: From physiopathology to therapeutical targeting. World J Nephrol 2015; 4:169-184. [PMID: 25949931 PMCID: PMC4419127 DOI: 10.5527/wjn.v4.i2.169] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 12/04/2014] [Accepted: 01/19/2015] [Indexed: 02/06/2023] Open
Abstract
Complement cascade is involved in several renal diseases and in renal transplantation. The different components of the complement cascade might represent an optimal target for innovative therapies. In the first section of the paper the authors review the physiopathology of complement involvement in renal diseases and transplantation. In some cases this led to a reclassification of renal diseases moving from a histopathological to a physiopathological classification. The principal issues afforded are: renal diseases with complement over activation, renal diseases with complement dysregulation, progression of renal diseases and renal transplantation. In the second section the authors discuss the several complement components that could represent a therapeutic target. Even if only the anti C5 monoclonal antibody is on the market, many targets as C1, C3, C5a and C5aR are the object of national or international trials. In addition, many molecules proved to be effective in vitro or in preclinical trials and are waiting to move to human trials in the future.
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77
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The perfect storm: HLA antibodies, complement, FcγRs, and endothelium in transplant rejection. Trends Mol Med 2015; 21:319-29. [PMID: 25801125 DOI: 10.1016/j.molmed.2015.02.004] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 01/29/2015] [Accepted: 02/11/2015] [Indexed: 02/07/2023]
Abstract
The pathophysiology of antibody-mediated rejection (AMR) in solid organ transplants is multifaceted and predominantly caused by antibodies directed against polymorphic donor human leukocyte antigens (HLAs). Despite the clearly detrimental impact of HLA antibodies (HLA-Abs) on graft function and survival, the prevention, diagnosis, and treatment of AMR remain a challenge. The histological manifestations of AMR reflect the signatures of HLA-Ab-triggered injury, specifically endothelial changes, recipient leukocytic infiltrate, and complement deposition. We review the interconnected mechanisms of HLA-Ab-mediated injury that might synergize in a 'perfect storm' of inflammation. Characterization of antibody features that are critical for effector functions may help to identify HLA-Abs that are more likely to cause rejection. We also highlight recent advances that may pave the way for new, more effective therapies.
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78
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Török K, Dezső B, Bencsik A, Uzonyi B, Erdei A. Complement receptor type 1 (CR1/CD35) expressed on activated human CD4+ T cells contributes to generation of regulatory T cells. Immunol Lett 2015; 164:117-24. [PMID: 25742728 DOI: 10.1016/j.imlet.2015.02.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 02/18/2015] [Accepted: 02/19/2015] [Indexed: 11/25/2022]
Abstract
The role of complement in the regulation of T cell immunity has been highlighted recently by several groups. We were prompted to reinvestigate the role of complement receptor type 1 (CR1, CD35) [corrected] in human T cells based on our earlier data showing that activated human T cells produce C3 (Torok et al. (2012) [48]) and also by results demonstrating that engagement of Membrane Cofactor Protein (MCP, CD46) induces a switch of anti-CD35-activated [corrected] helper T cells into regulatory T cells (Kemper et al. (2003) [17]). We demonstrate here that co-ligation of CD46 and CD35, [corrected] the two C3b-binding structures present on activated CD4+ human T cells significantly enhances CD25 expression, elevates granzyme B production and synergistically augments cell proliferation. The role of CR1 in the development of the Treg phenotype was further confirmed by demonstrating that its engagement enhances IL-10 production and reduces IFNγ release by the activated CD4+ T cells in the presence of excess IL-2. The functional in vivo relevance of our findings was highlighted by the immunohistochemical staining of tonsils, revealing the presence of CD4/CD35 [corrected] double positive lymphocytes mainly in the inter-follicular regions where direct contact between CD4+ T cells and B lymphocytes occurs. Regarding the in vivo relevance of the complement-dependent generation of regulatory T cells in secondary lymphoid organs we propose a scenario shown in the figure. The depicted process involves the sequential binding of locally produced C3 fragments to CD46 and CD35 [corrected] expressed on activated T cells, which - in the presence of excess IL-2 - leads to the development of Treg cells.
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Affiliation(s)
- Katalin Török
- MTA-ELTE Immunology Research Group, Budapest, Hungary
| | - Balázs Dezső
- Department of Pathology, Medical Center, University of Debrecen, Hungary
| | | | | | - Anna Erdei
- MTA-ELTE Immunology Research Group, Budapest, Hungary; Department of Immunology, Eötvös Loránd University, Budapest, Hungary.
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79
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Melis JPM, Strumane K, Ruuls SR, Beurskens FJ, Schuurman J, Parren PWHI. Complement in therapy and disease: Regulating the complement system with antibody-based therapeutics. Mol Immunol 2015; 67:117-30. [PMID: 25697848 DOI: 10.1016/j.molimm.2015.01.028] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 01/26/2015] [Accepted: 01/27/2015] [Indexed: 12/23/2022]
Abstract
Complement is recognized as a key player in a wide range of normal as well as disease-related immune, developmental and homeostatic processes. Knowledge of complement components, structures, interactions, and cross-talk with other biological systems continues to grow and this leads to novel treatments for cancer, infectious, autoimmune- or age-related diseases as well as for preventing transplantation rejection. Antibodies are superbly suited to be developed into therapeutics with appropriate complement stimulatory or inhibitory activity. Here we review the design, development and future of antibody-based drugs that enhance or dampen the complement system.
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Affiliation(s)
| | | | | | | | | | - Paul W H I Parren
- Genmab, Utrecht, The Netherlands; Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands.
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80
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Abstract
PURPOSE OF REVIEW Much research in transplantation focuses on treatments for rejection and induction of tolerance. Recent evidence has shown that initial inflammation induced by innate immune effectors after transplantation has a key role in modulating adaptive immune responses that cause organ rejection. Here, we describe the role of the innate immune system, particularly the complement activation pathways, and how they influence adaptive immune responses post-transplantation and current strategies, which are under development to block these innate pathways. RECENT FINDINGS Anaphylatoxins and their respective receptors are proving to be important in T-cell-mediated immunity and make attractive targets for therapies designed to promote tolerance in solid organ transplantation. Additionally, regulators of complement activation are currently being tested in clinical trials, with improvements in drug delivery. SUMMARY Preventing ischaemia-reperfusion injury in transplanted organs significantly reduces immune activation and promotes graft survival. Research into the mechanisms of complement activation in both native organ ischaemia and transplantation models detail emerging roles for complement intermediates that can serve as targets for intervention, with the aim of reducing early post-transplant inflammation, reducing the intensity of immunosuppressive regimens, leading to prolonged graft survival.
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81
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Karsten CM, Laumonnier Y, Eurich B, Ender F, Bröker K, Roy S, Czabanska A, Vollbrandt T, Figge J, Köhl J. Monitoring and cell-specific deletion of C5aR1 using a novel floxed GFP-C5aR1 reporter knock-in mouse. THE JOURNAL OF IMMUNOLOGY 2015; 194:1841-55. [PMID: 25589074 DOI: 10.4049/jimmunol.1401401] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Many of the biological properties of C5a are mediated through activation of its receptor (C5aR1), the expression of which has been demonstrated convincingly on myeloid cells, such as neutrophils, monocytes, and macrophages. In contrast, conflicting results exist regarding C5aR1 expression in dendritic cells (DCs) and lymphoid lineage cells. In this article, we report the generation of a floxed GFP-C5aR1 reporter knock-in mouse. Using this mouse strain, we confirmed strong C5aR1 expression in neutrophils from bone marrow, blood, lung, and spleen, as well as in peritoneal macrophages. Further, we show C5aR1 expression in lung eosinophils, lung- and lamina propria-resident and alveolar macrophages, bone marrow-derived DCs, and lung-resident CD11b(+) and monocyte-derived DCs, whereas intestinal and pulmonary CD103(+) DCs stained negative. Also, some splenic NKT cells expressed GFP, whereas naive NK cells and B2 cells lacked GFP expression. Finally, we did not observe any C5aR1 expression in naive or activated CD4(+) Th cells in vitro or in vivo. Mating the floxed GFP-C5aR1 mouse strain with LysMCre mice, we were able to specifically delete C5aR1 in neutrophils and macrophages, whereas C5aR1 expression was retained in DCs. In summary, our findings suggest that C5aR1 expression in mice is largely restricted to cells of the myeloid lineage. The novel floxed C5aR1 reporter knock-in mouse will prove useful to track C5aR1 expression in experimental models of acute and chronic inflammation and to conditionally delete C5aR1 in immune cells.
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Affiliation(s)
- Christian M Karsten
- Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany
| | - Yves Laumonnier
- Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany
| | - Benjamin Eurich
- Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany
| | - Fanny Ender
- Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany
| | - Katharina Bröker
- Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany
| | - Sreeja Roy
- Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany
| | - Anna Czabanska
- Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany
| | | | - Julia Figge
- Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany
| | - Jörg Köhl
- Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany; Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
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82
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von Rossum A, Laher I, Choy JC. Immune-mediated vascular injury and dysfunction in transplant arteriosclerosis. Front Immunol 2015; 5:684. [PMID: 25628623 PMCID: PMC4290675 DOI: 10.3389/fimmu.2014.00684] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 12/18/2014] [Indexed: 12/16/2022] Open
Abstract
Solid organ transplantation is the only treatment for end-stage organ failure but this life-saving procedure is limited by immune-mediated rejection of most grafts. Blood vessels within transplanted organs are targeted by the immune system and the resultant vascular damage is a main contributor to acute and chronic graft failure. The vasculature is a unique tissue with specific immunological properties. This review discusses the interactions of the immune system with blood vessels in transplanted organs and how these interactions lead to the development of transplant arteriosclerosis, a leading cause of heart transplant failure.
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Affiliation(s)
- Anna von Rossum
- Department of Molecular Biology and Biochemistry, Simon Fraser University , Burnaby, BC , Canada
| | - Ismail Laher
- Department of Anaesthesiology, Pharmacology and Therapeutics, University of British Columbia , Vancouver, BC , Canada
| | - Jonathan C Choy
- Department of Molecular Biology and Biochemistry, Simon Fraser University , Burnaby, BC , Canada
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83
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Mathern DR, Heeger PS. Molecules Great and Small: The Complement System. Clin J Am Soc Nephrol 2015; 10:1636-50. [PMID: 25568220 DOI: 10.2215/cjn.06230614] [Citation(s) in RCA: 185] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The complement cascade, traditionally considered an effector arm of innate immunity required for host defense against pathogens, is now recognized as a crucial pathogenic mediator of various kidney diseases. Complement components produced by the liver and circulating in the plasma undergo activation through the classical and/or mannose-binding lectin pathways to mediate anti-HLA antibody-initiated kidney transplant rejection and autoantibody-initiated GN, the latter including membranous glomerulopathy, antiglomerular basement membrane disease, and lupus nephritis. Inherited and/or acquired abnormalities of complement regulators, which requisitely limit restraint on alternative pathway complement activation, contribute to the pathogenesis of the C3 nephropathies and atypical hemolytic uremic syndrome. Increasing evidence links complement produced by endothelial cells and/or tubular cells to the pathogenesis of kidney ischemia-reperfusion injury and progressive kidney fibrosis. Data emerging since the mid-2000s additionally show that immune cells, including T cells and antigen-presenting cells, produce alternative pathway complement components during cognate interactions. The subsequent local complement activation yields production of the anaphylatoxins C3a and C5a, which bind to their respective receptors (C3aR and C5aR) on both partners to augment effector T-cell proliferation and survival, while simultaneously inhibiting regulatory T-cell induction and function. This immune cell-derived complement enhances pathogenic alloreactive T-cell immunity that results in transplant rejection and likely contributes to the pathogenesis of other T cell-mediated kidney diseases. C5a/C5aR ligations on neutrophils have additionally been shown to contribute to vascular inflammation in models of ANCA-mediated renal vasculitis. New translational immunology efforts along with the development of pharmacologic agents that block human complement components and receptors now permit testing of the intriguing concept that targeting complement in patients with an assortment of kidney diseases has the potential to abrogate disease progression and improve patient health.
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Affiliation(s)
- Douglas R Mathern
- Translational Transplant Research Center, Department of Medicine, Recanati Miller Transplant Institute, Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Peter S Heeger
- Translational Transplant Research Center, Department of Medicine, Recanati Miller Transplant Institute, Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, New York
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84
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Tsai EW, Reed EF. MHC class I signaling: new functional perspectives for an old molecule. ACTA ACUST UNITED AC 2015; 83:375-81. [PMID: 24828054 DOI: 10.1111/tan.12381] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Donor-specific antibodies are associated with refractory rejection episodes and poor allograft outcomes in solid organ transplantation. Our understanding of antibody-mediated allograft injury is expanding beyond complement deposition. In fact, unique mechanisms of alloantibodies are advancing our knowledge about transplant vasculopathy and antibody-mediated rejection. These include direct effects on the endothelium, resulting in the recruitment of leukocytes, chemokine and cytokine production, and stimulation of innate and adaptive alloresponses. These effects will be the focus of the following review.
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Affiliation(s)
- E W Tsai
- Mattel Children's Hospital UCLA, Division of Pediatric Nephrology, Los Angeles, CA, USA
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85
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Danobeitia JS, Djamali A, Fernandez LA. The role of complement in the pathogenesis of renal ischemia-reperfusion injury and fibrosis. FIBROGENESIS & TISSUE REPAIR 2014. [PMID: 25383094 DOI: 10.1186/1755‐1536‐7‐16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The complement system is a major component of innate immunity and has been commonly identified as a central element in host defense, clearance of immune complexes, and tissue homeostasis. After ischemia-reperfusion injury (IRI), the complement system is activated by endogenous ligands that trigger proteolytic cleavage of complement components via the classical, lectin and/or alternative pathway. The result is the formation of terminal complement components C3a, C5a, and the membrane attack complex (C5b-9 or MAC), all of which play pivotal roles in the amplification of the inflammatory response, chemotaxis, neutrophil/monocyte recruitment and activation, and direct tubular cell injury. However, recent evidence suggests that complement activity transcends innate host defense and there is increasing data suggesting complement as a regulator in processes such as allo-immunity, stem cell differentiation, tissue repair, and progression to fibrosis. In this review, we discuss recent advances addressing the role of complement as a regulator of IRI and renal fibrosis after organ donation for transplantation. We will also briefly discuss currently approved therapies that target complement activity in kidney ischemia-reperfusion and transplantation.
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Affiliation(s)
- Juan S Danobeitia
- Department of Surgery, Division of Transplantation, University of Wisconsin-Madison School of Medicine and Public Health, H4/782 Clinical Science Center, 600 Highland Avenue, 53792 Madison, WI, USA
| | - Arjang Djamali
- Department of Medicine, Division of Nephrology, University of Wisconsin- Madison School of Medicine and Public Health, UW Medical Foundation Centennial Building, 1685 Highland Avenue, 53705 Madison, WI, USA
| | - Luis A Fernandez
- Department of Surgery, Division of Transplantation, University of Wisconsin-Madison School of Medicine and Public Health, H4/782 Clinical Science Center, 600 Highland Avenue, 53792 Madison, WI, USA
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86
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Danobeitia JS, Djamali A, Fernandez LA. The role of complement in the pathogenesis of renal ischemia-reperfusion injury and fibrosis. FIBROGENESIS & TISSUE REPAIR 2014; 7:16. [PMID: 25383094 PMCID: PMC4224961 DOI: 10.1186/1755-1536-7-16] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Accepted: 09/17/2014] [Indexed: 01/04/2023]
Abstract
The complement system is a major component of innate immunity and has been commonly identified as a central element in host defense, clearance of immune complexes, and tissue homeostasis. After ischemia-reperfusion injury (IRI), the complement system is activated by endogenous ligands that trigger proteolytic cleavage of complement components via the classical, lectin and/or alternative pathway. The result is the formation of terminal complement components C3a, C5a, and the membrane attack complex (C5b-9 or MAC), all of which play pivotal roles in the amplification of the inflammatory response, chemotaxis, neutrophil/monocyte recruitment and activation, and direct tubular cell injury. However, recent evidence suggests that complement activity transcends innate host defense and there is increasing data suggesting complement as a regulator in processes such as allo-immunity, stem cell differentiation, tissue repair, and progression to fibrosis. In this review, we discuss recent advances addressing the role of complement as a regulator of IRI and renal fibrosis after organ donation for transplantation. We will also briefly discuss currently approved therapies that target complement activity in kidney ischemia-reperfusion and transplantation.
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Affiliation(s)
- Juan S Danobeitia
- Department of Surgery, Division of Transplantation, University of Wisconsin-Madison School of Medicine and Public Health, H4/782 Clinical Science Center, 600 Highland Avenue, 53792 Madison, WI, USA
| | - Arjang Djamali
- Department of Medicine, Division of Nephrology, University of Wisconsin- Madison School of Medicine and Public Health, UW Medical Foundation Centennial Building, 1685 Highland Avenue, 53705 Madison, WI, USA
| | - Luis A Fernandez
- Department of Surgery, Division of Transplantation, University of Wisconsin-Madison School of Medicine and Public Health, H4/782 Clinical Science Center, 600 Highland Avenue, 53792 Madison, WI, USA
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87
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Kshirsagar S, Riedl M, Billing H, Tönshoff B, Thangavadivel S, Steuber C, Staude H, Wechselberger G, Edelbauer M. Akt-dependent enhanced migratory capacity of Th17 cells from children with lupus nephritis. THE JOURNAL OF IMMUNOLOGY 2014; 193:4895-903. [PMID: 25339666 DOI: 10.4049/jimmunol.1400044] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Th17 cells infiltrate the kidneys of patients with lupus nephritis (LN) and are critical for the pathogenesis of this disease. In this study, we show that enhanced activity of Stat3 in CD4(+)CD45RA(-)Foxp3(-) and Foxp3(low) effector T cells from children with LN correlates with increased frequencies of IL-17-producing cells within these T cell populations. The levels of retinoic acid-related orphan receptor c and IL-17 mRNA are significantly higher in PBMCs from children with LN than in those from controls. Mammalian target of rapamycin inhibition by rapamycin reduces both Stat3 activation in effector T cells and the frequency of IL-17-producing T cells in lupus patients. Complement factor C5a slightly increases the expression of IL-17 and induces activation of Akt in anti-CD3-activated lupus effector T cells. Th17 cells from children with LN exhibit high Akt activity and enhanced migratory capacity. Inhibition of the Akt signaling pathway significantly decreases Th17 cell migration. These findings indicate that the Akt signaling pathway plays a significant role in the migratory activity of Th17 cells from children with LN and suggest that therapeutic modulation of the Akt activity may inhibit Th17 cell trafficking to sites of inflammation and thus suppress chronic inflammatory processes in children with LN.
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Affiliation(s)
- Sudhir Kshirsagar
- Department of Pediatrics I, Innsbruck Medical University, A-6020 Innsbruck, Austria
| | - Magdalena Riedl
- Department of Pediatrics I, Innsbruck Medical University, A-6020 Innsbruck, Austria
| | - Heiko Billing
- University Children's Hospital, Heidelberg, 69120 Heidelberg, Germany; University Children's Hospital, 72076 Tuebeingen, Germany
| | - Burkhard Tönshoff
- University Children's Hospital, Heidelberg, 69120 Heidelberg, Germany
| | | | | | - Hagen Staude
- Department of Pediatrics, University Children's Hospital, 18075 Rostock, Germany; and
| | - Gottfried Wechselberger
- Department of Plastic, Aesthetic, and Reconstructive Surgery, Hospital of the Barmherzige Brüder Salzburg, Paracelsus Medical University, 5020 Salzburg, Austria
| | - Monika Edelbauer
- Department of Pediatrics I, Innsbruck Medical University, A-6020 Innsbruck, Austria;
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88
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Lu Y, Hu XB. C5a stimulates the proliferation of breast cancer cells via Akt-dependent RGC-32 gene activation. Oncol Rep 2014; 32:2817-23. [PMID: 25230890 DOI: 10.3892/or.2014.3489] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 08/14/2014] [Indexed: 11/05/2022] Open
Abstract
Complement system activation contributes to various immune and inflammatory diseases, as well as cancers.However, the role of complement activation in the proliferation of cancer cells is not clear. In the present study, we investigated the consequences of complement activation on the proliferation of breast cancer cells and its possible mechanisms. We focused our study on the potential roles of the anaphylatoxins C3a and C5a in the proliferation of human breast cancer, as two important immune mediators generated after complement activation. Our study revealed that C5a stimulation, but not C3a, enhanced the proliferation of human breast cancer cells in vitro. Moreover, the expression of response gene to complement 32 (RGC-32) was pronounced in breast cancer cells in response to C5a stimulation. Notably, blockade of the C5a receptor markedly reduced the expression of RGC-32 and the proliferation of breast cancer cells stimulated by C5a. Meanwhile, silencing of RGC-32 expression reduced the proliferation of breast cancer cells induced by C5a treatment. Further investigation revealed that Akt activation was involved in C5a-induced RGC-32 expression and breast cancer cell proliferation. In conclusion, the present study indicates that C5a may promote the proliferation of breast cancer cells through Akt1 activation of the RGC-32 gene.
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Affiliation(s)
- Yi Lu
- Department of General Surgery, Suzhou Kowloon Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, Suzhou, Jiangsu 215021, P.R. China
| | - Xiao-Bo Hu
- Department of Breast Surgery, The Affiliated Tumor Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, P.R. China
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89
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Abstract
Complement proteins are generated both by the liver (systemic compartment) and by peripheral tissue-resident cells and migratory immune cells (local compartment). The immune cell-derived, alternative pathway complement components activate spontaneously, yielding local, but not systemic, production of C3a and C5a. These anaphylatoxins bind to their respective G-protein-coupled receptors, the C3a receptor and the C5a receptor, expressed on T cells and antigen-presenting cells, leading to their reciprocal activation and driving T-cell differentiation, expansion, and survival. Complement deficiency or blockade attenuates T-cell-mediated autoimmunity and delays allograft rejection in mice. Increasing complement activation, achieved by genetic removal of the complement regulatory protein decay accelerating factor, enhances murine T-cell immunity and accelerates allograft rejection. Signaling through the C3a receptor and the C5a receptor reduces suppressive activity of natural regulatory T cells and the generation and stability of induced regulatory T cells. The concepts, initially generated in mice, recently were confirmed in human immune cells, supporting the need for testing of complement targeting therapies in organ transplants patients.
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Affiliation(s)
- Paolo Cravedi
- Department of Medicine, Recanati Miller Transplant Institute and Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY
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90
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Cravedi P, Heeger PS. Complement as a multifaceted modulator of kidney transplant injury. J Clin Invest 2014; 124:2348-54. [PMID: 24892709 DOI: 10.1172/jci72273] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Improvements in clinical care and immunosuppressive medications have positively affected outcomes following kidney transplantation, but graft survival remains suboptimal, with half-lives of approximately 11 years. Late graft loss results from a confluence of processes initiated by ischemia-reperfusion injury and compounded by effector mechanisms of uncontrolled alloreactive T cells and anti-HLA antibodies. When combined with immunosuppressant toxicity, post-transplant diabetes and hypertension, and recurrent disease, among other factors, the result is interstitial fibrosis, tubular atrophy, and graft failure. Emerging evidence over the last decade unexpectedly identified the complement cascade as a common thread in this process. Complement activation and function affects allograft injury at essentially every step. These fundamental new insights, summarized herein, provide the foundation for testing the efficacy of various complement antagonists to improve kidney transplant function and long-term graft survival.
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91
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Antibody-mediated graft injury: complement-dependent and complement-independent mechanisms. Curr Opin Organ Transplant 2014; 19:33-40. [PMID: 24316758 DOI: 10.1097/mot.0000000000000040] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE OF REVIEW Antibody-mediated rejection (AMR) is emerging as the leading cause of chronic rejection and allograft failure. Traditionally, the mechanisms of graft injury mediated by donor-specific antibodies beyond complement activation were not well appreciated. However, an evolving paradigm of Fc-independent antibody functions, along with clinical recognition of C4d-negative AMR, has increased awareness of the action of antibodies leading to endothelial activation and dysfunction. RECENT FINDINGS Herein, we address current clinical trends, including the signature of microvascular inflammation in biopsies of grafts undergoing AMR, the prevalence of antibodies to human leukocyte antigen class II DQ locus (HLA-DQ) and non-HLA targets, and the functional characterization of HLA immunoglobulin G (IgG) subclasses and complement-fixing capacity. We also discuss recent experimental evidence revealing new mechanisms of endothelial and smooth muscle cell activation by HLA antibodies, which may contribute to vascular inflammation and chronic rejection. Finally, we touch upon novel discoveries of the interplay between antibodies, the complement system, and CD4 T-cell-mediated alloimmunity. SUMMARY The current literature suggests that, although complement-fixing antibodies may have some prognostic value for graft outcome, complement-independent mechanisms of graft injury are increasingly relevant. Therapeutic strategies, which target endothelial activation induced by antibodies may ameliorate vascular inflammation and mononuclear cell infiltration characteristic of AMR.
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