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Detection of otosclerosis-specific measles virus receptor (cd46) protein isoforms. ISRN OTOLARYNGOLOGY 2013; 2013:479482. [PMID: 23864959 PMCID: PMC3706069 DOI: 10.1155/2013/479482] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Accepted: 06/05/2013] [Indexed: 11/18/2022]
Abstract
Genetic predisposition of otosclerosis has long been suspected, but unclarified. Unique coexpression pattern of measles virus receptor (CD46) splicing isoforms in the human otic capsule is assumed, since otosclerosis is a measles virus-associated organ-specific disease. In order to identify CD46 involved in the pathogenesis of otosclerosis, we used representative groups of histologically diagnosed otosclerotic, nonotosclerotic, and normal stapes footplates (n = 109). Consecutive histopathological examinations and CD46-specific Western blot analysis were performed. Normal and nonotosclerotic stapes footplates showed consistent expression of the conventional c, d, e, f, and l CD46 isoforms. In contrast, four novel isoforms (os1–4) translated as intact proteins were additionally detected in each otosclerotic specimen. The study herein presented provides evidence for the otosclerosis-associated expression pattern of CD46. This finding might explain the organ-specific, virus-associated and autoimmune-inflammatory pathogenesis of otosclerosis. Regarding our current knowledge, this is the first report that confirms the presence of four new disease-specific protein variants of CD46.
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Abstract
Complement has been studied for over a century and its role in promoting the effector side of antibody-mediated immune reactions and of inducing inflammation is well understood. Nevertheless, it has proved surprisingly difficult to translate this information into pharmaceutical agents that can be used to treat immunopathological and inflammatory disease. There are, however, now clear signs that this situation will change. New types of therapeutic agents to interfere with complement function are being developed and it has become apparent quite recently that some common and otherwise untreatable diseases such as age-related macular degeneration are very largely due to mutations in the complement system that leads to a hyperinflammatory state. This has stimulated a renaissance of interest in the complement system as a therapeutic target and in this short review we discuss the possible ways of taking complement to the clinic, and the indications for which this may be carried out.
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Affiliation(s)
- P J Lachmann
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.
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Oliaro J, Pasam A, Waterhouse NJ, Browne KA, Ludford-Menting MJ, Trapani JA, Russell SM. Ligation of the cell surface receptor, CD46, alters T cell polarity and response to antigen presentation. Proc Natl Acad Sci U S A 2006; 103:18685-90. [PMID: 17116876 PMCID: PMC1693723 DOI: 10.1073/pnas.0602458103] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Lymphocyte function in vivo is dictated by multiple external cues, but the integration of different signals is not well understood. Here, we show that competition for the axis of polarization dictates functional outcomes. We investigated the effect of ligation of the immunoregulatory cell surface receptor, CD46, on lymphocyte polarity during antigen presentation and cytotoxic effector function. Ligation of CD46 on human T cells prevented recruitment of the microtubule organizing center, CD3, and perforin to the interface with the antigen-presenting cell and caused a reduction in IFN-gamma production. In human NK cells, similar changes in polarity induced by CD46 ligation inhibited the recruitment of the microtubule organizing center and perforin to the interface with target cells and correlated with reduced killing. These data indicate that external signals can alter lymphocyte polarization toward antigen-presenting cells or target cells, inhibiting lymphocyte function.
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Affiliation(s)
- Jane Oliaro
- *Immune Signalling Laboratory and
- Department of Pathology, Faculty of Medicine, University of Melbourne, Melbourne VIC 3010, Australia; and
| | - Anupama Pasam
- *Immune Signalling Laboratory and
- Department of Pathology, Faculty of Medicine, University of Melbourne, Melbourne VIC 3010, Australia; and
| | - Nigel J. Waterhouse
- Cancer Cell Death Laboratory, Peter MacCallum Cancer Centre, and
- Department of Pathology, Faculty of Medicine, University of Melbourne, Melbourne VIC 3010, Australia; and
| | - Kylie A. Browne
- Cancer Cell Death Laboratory, Peter MacCallum Cancer Centre, and
| | | | - Joseph A. Trapani
- Cancer Cell Death Laboratory, Peter MacCallum Cancer Centre, and
- Department of Pathology, Faculty of Medicine, University of Melbourne, Melbourne VIC 3010, Australia; and
| | - Sarah M. Russell
- *Immune Signalling Laboratory and
- Centre for MicroPhotonics, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn VIC 3122, Australia
- To whom correspondence should be addressed at:
Peter MacCallum Cancer Centre, St. Andrew's Place, East Melbourne VIC 3002, Australia. E-mail:
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Abstract
The involvement of complement in the pathogenesis of a great number of partly life threatening diseases defines the importance to develop inhibitors which specifically interfere with its deleterious action. Endogenous soluble complement-inhibitors, antibodies or low molecular weight antagonists, either blocking key proteins of the cascade reaction or neutralizing the action of the complement-derived anaphylatoxins have successfully been tested in various animal models over the past years. Promising results consequently led to first clinical trials. This review is focused on different approaches for the development of inhibitors, on their site of action in the cascade, on possible indications for complement inhibition based on experimental animal data, and on potential side effects of such treatment.
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Affiliation(s)
- Tom E Mollnes
- Institute of Immunology, Rikshospitalet University Hospital and University of Oslo, N-0027 Oslo, Norway.
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Abstract
The continued and growing success of lung allotransplantation has intensified the worldwide shortage of donor organs. Yet, xenotransplantation remains a daunting challenge. Additional molecular incompatibilities and unforeseen complications will continue to be discovered. Progress has been made, notably on the generation of alpha-Gal double knockout pigs. Progressive increases in organ survival times have been seen for most organs after significant investments of time and money. The lung continues to be an organ with the lowest supply of cadaveric donors and the least potential for expanded living donation or mechanical alternatives. As such, the impetus for xenotransplantation is strong. The lung appears to be exquisitely sensitive to xenograft rejection and resistant to strategies that have been moderately successful in other organs. A complex program involving genetically modified donor organs, recipient preparation for antibody removal or tolerance promotion, and multitargeted drug therapy will likely be required for successful clinical application.
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Affiliation(s)
- Thomas K Waddell
- Department of Surgery, Division of Thoracic Surgery, Toronto General Hospital, 200 Elizabeth Street, EN 10-233, Toronto, Ontario M5G 2C4, Canada.
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Roos A, Daha MR. Antibody-mediated activation of the classical complement pathway in xenograft rejection. Transpl Immunol 2002; 9:257-70. [PMID: 12180840 DOI: 10.1016/s0966-3274(02)00042-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Transplant rejection is a multifactorial process involving complex interactions between components of the innate and the acquired immune system. In view of the shortage of donor organs available for transplantation, xenotransplantation of pig organs into man has been considered as a potential solution. However, in comparison to allografts, xenografts are subject to extremely potent rejection processes that are currently incompletely defined. Consequently, an appropriate and safe treatment protocol ensuring long-term graft survival is not yet available. The first barrier that has to be taken for a xenograft is hyperacute rejection, a rapid process induced by the binding of pre-formed antibodies from the host to the graft endothelium, followed by activation of the classical complement pathway. The present review concentrates on the role of antibodies and complement in xenograft rejection as well as on the approaches for treatment that target these components. The first part focuses on porcine xenoantigens that are recognized by human xenoreactive antibodies and the different treatment strategies that aim on interference in antibody binding. The second part of the review deals with complement activation by xenoreactive antibodies, and summarizes the role of complement in the induction of endothelial cell damage and cell activation. Finally, various options that are currently under development for complement inhibition are discussed, with special reference to the specific inhibition of the classical complement pathway by soluble complement inhibitors.
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Affiliation(s)
- Anja Roos
- Department of Nephrology, Leiden University Medical Center, The Netherlands.
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Salerno CT, Kulick DM, Yeh CG, Guzman-Paz M, Higgins PJ, Benson BA, Park SJ, Shumway SJ, Bolman RM, Dalmasso AP. A soluble chimeric inhibitor of C3 and C5 convertases, complement activation blocker-2, prolongs graft survival in pig-to-rhesus monkey heart transplantation. Xenotransplantation 2002; 9:125-34. [PMID: 11897005 DOI: 10.1034/j.1399-3089.2002.1o042.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Complement plays a critical role in many pathologic processes and in xenograft rejection. Therefore, effective complement inhibitors are of great interest. In pig-to-primate organ transplantation, hyperacute rejection results from antibody deposition and complement activation. Complement activation blocker-2 (CAB-2), a recombinant soluble chimeric protein derived from human decay accelerating factor (DAF) and membrane cofactor protein, inhibits C3 and C5 convertases of both classical and alternative pathways. CAB-2 reduces complement-mediated tissue injury of a pig heart perfused ex vivo with human blood. Therefore, we studied the efficacy of CAB-2 when a pig heart is transplanted heterotopically into rhesus monkeys receiving no immunosuppression. Graft survival in three control monkeys was 1.26 +/- 0.2 h; it was markedly prolonged in eight monkeys that received CAB-2. Of the six monkeys that received a single dose of CAB-2 (15 mg/kg i.v.), four had graft survivals of 21, 95, 96, and 108 h, and two died at 7 to 11 h post-transplant with a beating graft, as a result of technical complications. The two monkeys given multiple doses of CAB-2 had graft survivals of 95 and 96 h. CAB-2 markedly inhibited complement activation, as shown by a strong reduction in generation of C3a and SC5b-9. At graft rejection, tissue deposition of iC3b, C4 and C9 was similar or slightly reduced from controls, and deposition of IgG, IgM, C1q and fibrin did not change. Thus, complement inhibition with CAB-2 abrogates hyperacute rejection of pig hearts transplanted into rhesus monkeys, but does not prevent delayed/acute vascular rejection. These studies demonstrate that the beneficial effects of complement inhibition on survival of a pig heart xenograft in rhesus monkeys are similar to those in other primate species and that CAB-2 may be useful in xenotransplantation and other complement-mediated conditions.
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Abstract
Xenotransplantation is being pursued vigorously to solve the shortage of allogeneic donor organs. Experimental studies of the major xenoantigen (Gal) and of complement regulation enable model xenografts to survive hyperacute rejection. When the Gal antigen is removed or reduced and complement activation is controlled, the major barriers to xenograft survival include unregulated coagulation within the graft and cellular reactions involving macrophages, neutrophils, natural killer (NK) cells, and T lymphocytes. Unlike allografts, where specific immune responses are the sole barrier to graft survival, molecular differences between xenograft and recipient that affect normal receptor-ligand interactions (largely active at the cell surface and which may not be immunogenic), are also involved in xenograft failure. Transgenic strategies provide the best options to control antigen expression, complement activation, and coagulation. Although the Gal antigen can be eliminated by gene knockout in mice, that outcome has only become a possibility in pigs due to the recent cloning of pigs after nuclear transfer. Instead, the use of transgenic glycosyl transferase enzymes and glycosidases, which generate alternative terminal carbohydrates on glycolipids and glycoproteins, has reduced antigen in experimental models. As a result, novel strategies are being tested to seek the most effective solution. Transgenic pigs expressing human complement-regulating proteins (DAF/CD55, MCP/CD46, or CD59) have revealed that disordered regulation of the coagulation system requires attention. There will undoubtedly be other molecular incompatibilities that need addressing. Xenotransplantation, however, offers hope as a therapeutic solution and provides much information about homeostatic mechanisms.
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Affiliation(s)
- M S Sandrin
- Molecular Immunogenetics Laboratory, The Austin Research Institute, Heidelberg, Victoria, Australia.
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Auchincloss H. Literature update 2000, part 1. Xenotransplantation 2000; 7:230-4. [PMID: 11021669 DOI: 10.1034/j.1399-3089.2000.00079.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- H Auchincloss
- Surgical Services, Massachusetts General Hospital, Boston 02114, USA
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