401
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Robson SC, Siegel JB, Lesnikoski BA, Kopp C, Candinas D, Ryan U, Bach FH. Aggregation of human platelets induced by porcine endothelial cells is dependent upon both activation of complement and thrombin generation. Xenotransplantation 1996. [DOI: 10.1111/j.1399-3089.1996.tb00115.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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402
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Mora M, Mulder LC, Lazzeri M, Boschi M, Ciccopiedi E, Melli CM, Bruzzone P, Alfani D, Cortesini R, Rossini M. Protection from complement-mediated injury in livers and kidneys of transgenic mice expressing human complement regulators. Xenotransplantation 1996. [DOI: 10.1111/j.1399-3089.1996.tb00120.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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403
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Cozzi E, Langford G, Pino-Chávez G, Wright L, Levy A, Miller N, Davies H, Chatterjee M, Lancaster R, Tolan M, White D. Longitudinal analysis of the expression of human decay accelerating factor (HDAF) on lymphocytes, in the plasma, and in the skin biopsies of transgenic pigs. Xenotransplantation 1996. [DOI: 10.1111/j.1399-3089.1996.tb00129.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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404
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Yang YG, Sergio JJ, Swenson K, Glaser RM, Monroy R, Sykes M. Donor-specific growth factors promote swine hematopoiesis in severe combined immune deficient mice. Xenotransplantation 1996. [DOI: 10.1111/j.1399-3089.1996.tb00125.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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405
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Takeuchi Y, Porter CD, Strahan KM, Preece AF, Gustafsson K, Cosset FL, Weiss RA, Collins MK. Sensitization of cells and retroviruses to human serum by (alpha 1-3) galactosyltransferase. Nature 1996; 379:85-8. [PMID: 8538747 DOI: 10.1038/379085a0] [Citation(s) in RCA: 223] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Mammalian C-type retroviruses are inactivated by human serum, following triggering of the classical complement cascade. This may have inhibited transmission to humans of C-type oncoviruses from other mammals. Indeed, the retroviruses human immunodeficiency virus and human T-cell leukaemia virus are resistant to human complement. Antibody-independent activation of human C1q, the first component of the classical pathway, by retroviral envelope proteins has been described. However, retroviruses produced from human cells are resistant to inactivation by human complement and human serum is known to contain antibodies directed against carbohydrates on retroviral envelopes. Gal(alpha 1-3)Gal terminal carbohydrates are expressed by most mammals but are absent in humans, which lack a functional (alpha 1-3)galactosyltransferase gene. Here, we demonstrate that anti-Gal(alpha 1-3)Gal antibodies in human serum inactivate retroviruses produced from animal cells. Expression of porcine (alpha 1-3)galactosyltransferase in human cells renders the cells and the retroviruses they produce sensitive to human serum.
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Affiliation(s)
- Y Takeuchi
- Chester Beatty Laboratories, Institute of Cancer Research, London, UK
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406
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Abstract
The complement system has developed a remarkably simple but elegant manner of regulating itself. It has faced and successfully dealt with how to facilitate activation on a microbe while preventing the same on host tissue. It solved this problem primarily by creating a series of secreted and membrane-regulatory proteins that prevent two highly undesirable events: activation in the fluid phase (no target) and on host tissue (inappropriate target). Also, if not checked, even on an appropriate target, the system would go to exhaustion and have nothing left for the next microbe. Therefore, the complement enzymes have an intrinsic instability and the fluid-phase control proteins play a major role in limiting activation in time. The symmetry of the regulatory process between fluid phase and membrane inhibitors at the C4/C3 step of amplification and convertase formation as well as at the MAC steps are particularly striking features of the self/nonself discrimination system. The use of glycolipid anchored proteins on membranes to decay enzymes and block membrane insertion events is unlikely to be by chance. Finally, it is economical for the cofactor regulatory activity to produce derivatives of C3b that now specifically engage additional receptors. Likewise, C1-Inh leads to C1q remaining on the immune complex to interact with the C1q receptor. Thus the complement system is designed to allow rapid, efficient, unimpeded activation on an appropriate foreign target while regulatory proteins intervene to prevent three undesirable consequences of complement activation: excessive activation on a single target, fluid phase activation, and activation on self.
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Affiliation(s)
- M K Liszewski
- Department of Medicine, Washington University School of Medicine, St Louis, Missouri 63110, USA
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407
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Affiliation(s)
- J L Platt
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, USA
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408
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409
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Sandrin MS, Fodor WL, Mouhtouris E, Osman N, Cohney S, Rollins SA, Guilmette ER, Setter E, Squinto SP, McKenzie IF. Enzymatic remodelling of the carbohydrate surface of a xenogenic cell substantially reduces human antibody binding and complement-mediated cytolysis. Nat Med 1995; 1:1261-7. [PMID: 7489406 DOI: 10.1038/nm1295-1261] [Citation(s) in RCA: 235] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The major obstacle to successful discordant xenotransplantation is the phenomenon of hyperacute rejection (HAR). In the pig-to-primate discordant transplant setting, HAR results from the deposition of high-titre anti-alpha-galactosyl antibodies and complement activation leading to endothelial cell destruction and rapid graft failure. To overcome HAR, we developed an enzymatic carbohydrate remodelling strategy designed to replace expression of the Gal alpha-1,3-Gal xenoepitope on the surface of porcine cells with the non-antigenic universal donor human blood group O antigen, the alpha-1,2-fucosyl lactosamine moiety (H-epitope). Xenogenic cells expressing the human alpha-1,2-fucosyltransferase expressed high levels of the H-epitope and significantly reduced Gal alpha-1,3-Gal expression. As a result, these cells were shown to be resistant to human natural antibody binding and complement-mediated cytolysis.
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Affiliation(s)
- M S Sandrin
- Molecular Immunogenetics Laboratory, Austin Research Institute, Heidelberg, Vic., Australia
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410
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Magee JC, Collins BH, Harland RC, Lindman BJ, Bollinger RR, Frank MM, Platt JL. Immunoglobulin prevents complement-mediated hyperacute rejection in swine-to-primate xenotransplantation. J Clin Invest 1995; 96:2404-12. [PMID: 7593628 PMCID: PMC185892 DOI: 10.1172/jci118297] [Citation(s) in RCA: 152] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Immunoglobulins regulate the complement system by activating complement on foreign surfaces and diverting reactive complement proteins away from autologous cell surfaces. Based on this model, we explored the ability of Ig to balance complement activation versus control in a pig-to-primate cardiac xenotransplantation model in which the binding of xenoreactive antibodies of the recipient to graft blood vessels and the activation of complement cause hyperacute rejection. Human IgG added to human serum caused a dose-dependent decrease in deposition of iC3b, cytotoxicity, and heparan sulfate release when the serum was incubated with porcine endothelial cells. This decrease was not caused by alteration in antibody binding or consumption of complement but presumably reflected decreased formation of C3 convertase on the endothelial cells. Infusion of purified human IgG into nonhuman primates prevented hyperacute rejection of porcine hearts transplanted into the primates. As expected, the transplants contained deposits of recipient Ig and C1q but not other complement components. The inhibition of complement on endothelial cell surfaces and in the xenotransplantation model supports the idea that IgG regulates the classical complement pathway and supports therapeutic use of that agent in humoral-mediated disease.
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Affiliation(s)
- J C Magee
- Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
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411
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Hayashi S, Emi N, Isobe KI, Okada H, Yokoyama I, Takagi H. Evidence that double transfection to xenoendothelial cells using GPI-anchoring complement regulatory factor (DAF and HRF20) genes is useful for the inhibition of human complement-mediated cytolysis. Xenotransplantation 1995. [DOI: 10.1111/j.1399-3089.1995.tb00110.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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412
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413
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Affiliation(s)
- E Cozzi
- Instituto de Medicina Interna, Padua University, Italy
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414
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Bach FH, Robson SC, Winkler H, Ferran C, Stuhlmeier KM, Wrighton CJ, Hancock WW. Barriers to xenotransplantation. Nat Med 1995; 1:869-73. [PMID: 7585204 DOI: 10.1038/nm0995-869] [Citation(s) in RCA: 213] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- F H Bach
- Sandoz Center for Immunobiology, New England Deaconess Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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415
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Abstract
Once complement-mediated HAR has been inhibited, the full spectrum of cellular and antibody-mediated inflammatory and immune responses characteristic of acute and chronic rejection will need to be counter-manded. But the fact remains that if xenotransplantation is to become a clinical reality, a clinically relevant means of inhibiting complement activation will be required. Soluble complement receptor type 1 provides such a therapeutic option and an option where the dosing regimen is under the control of the physician and can be adjusted in response to the needs of the patient.
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Affiliation(s)
- U S Ryan
- T Cell Sciences, Inc., Needham, Massachusetts 02194, USA
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416
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Affiliation(s)
- J W Fabre
- Institute of Child Health, University of London, UK
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