1
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Revisiting an IgG Fc Loss-of-Function Experiment: the Role of Complement in HIV Broadly Neutralizing Antibody b12 Activity. mBio 2021; 12:e0174321. [PMID: 34634936 PMCID: PMC8510540 DOI: 10.1128/mbio.01743-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The role of the complement system in HIV-1 immunity and pathogenesis is multifaceted, and an improved understanding of complement activities mediated by HIV-1-specific antibodies has the potential to inform and advance clinical development efforts. A seminal nonhuman primate challenge experiment suggested that complement was dispensable for the protective effect of the early broadly neutralizing antibody (bnAb) b12, but recent experiments have raised questions about the breadth of circumstances under which this conclusion may hold. Here, we reassess the original observation using Fc variants of IgG1 b12 that enhance complement activity and report that complement fixation on recombinant antigen, virions, and cells and complement-dependent viral and cellular lysis in vitro vary among bnAbs. Specifically, while the clinically significant V3 glycan-specific bnAb 10-1074 demonstrates activity, we found that b12 does not meaningfully activate the classical complement cascade. Consistent with avid engagement by C1q and its complex system of regulatory factors, these results suggest that complement-mediated antibody activities demonstrate a high degree of context dependence and motivate revisiting the role of complement in antibody-mediated prevention of HIV-1 infection by next-generation bnAbs in new translational studies in animal models.
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2
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Grzywa TM, Nowis D, Golab J. The role of CD71 + erythroid cells in the regulation of the immune response. Pharmacol Ther 2021; 228:107927. [PMID: 34171326 DOI: 10.1016/j.pharmthera.2021.107927] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 05/13/2021] [Accepted: 05/18/2021] [Indexed: 02/07/2023]
Abstract
Complex regulation of the immune response is necessary to support effective defense of an organism against hostile invaders and to maintain tolerance to harmless microorganisms and autoantigens. Recent studies revealed previously unappreciated roles of CD71+ erythroid cells (CECs) in regulation of the immune response. CECs physiologically reside in the bone marrow where erythropoiesis takes place. Under stress conditions, CECs are enriched in some organs outside of the bone marrow as a result of extramedullary erythropoiesis. However, the role of CECs goes well beyond the production of erythrocytes. In neonates, increased numbers of CECs contribute to their vulnerability to infectious diseases. On the other side, neonatal CECs suppress activation of immune cells in response to abrupt colonization with commensal microorganisms after delivery. CECs are also enriched in the peripheral blood of pregnant women as well as in the placenta and are responsible for the regulation of feto-maternal tolerance. In patients with cancer, anemia leads to increased frequency of CECs in the peripheral blood contributing to diminished antiviral and antibacterial immunity, as well as to accelerated cancer progression. Moreover, recent studies revealed the role of CECs in HIV and SARS-CoV-2 infections. CECs use a full arsenal of mechanisms to regulate immune response. These cells suppress proinflammatory responses of myeloid cells and T-cell proliferation by the depletion of ʟ-arginine by arginase. Moreover, CECs produce reactive oxygen species to decrease T-cell proliferation. CECs also secrete cytokines, including transforming growth factor β (TGF-β), which promotes T-cell differentiation into regulatory T-cells. Here, we comprehensively describe the role of CECs in orchestrating immune response and indicate some therapeutic approaches that might be used to regulate their effector functions in the treatment of human conditions.
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Affiliation(s)
- Tomasz M Grzywa
- Department of Immunology, Medical University of Warsaw, Nielubowicza 5 Street, 02-097 Warsaw, Poland; Doctoral School, Medical University of Warsaw, Zwirki and Wigury 61 Street, 02-091 Warsaw, Poland; Laboratory of Experimental Medicine, Medical University of Warsaw, Nielubowicza 5 Street, 02-097 Warsaw, Poland.
| | - Dominika Nowis
- Department of Immunology, Medical University of Warsaw, Nielubowicza 5 Street, 02-097 Warsaw, Poland; Laboratory of Experimental Medicine, Medical University of Warsaw, Nielubowicza 5 Street, 02-097 Warsaw, Poland.
| | - Jakub Golab
- Department of Immunology, Medical University of Warsaw, Nielubowicza 5 Street, 02-097 Warsaw, Poland; Centre of Preclinical Research, Medical University of Warsaw, Banacha 1b Street, 02-097 Warsaw, Poland.
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3
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Kumar NA, Kunnakkadan U, Thomas S, Johnson JB. In the Crosshairs: RNA Viruses OR Complement? Front Immunol 2020; 11:573583. [PMID: 33133089 PMCID: PMC7550403 DOI: 10.3389/fimmu.2020.573583] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 08/24/2020] [Indexed: 12/02/2022] Open
Abstract
Complement, a part of the innate arm of the immune system, is integral to the frontline defense of the host against innumerable pathogens, which includes RNA viruses. Among the major groups of viruses, RNA viruses contribute significantly to the global mortality and morbidity index associated with viral infection. Despite multiple routes of entry adopted by these viruses, facing complement is inevitable. The initial interaction with complement and the nature of this interaction play an important role in determining host resistance versus susceptibility to the viral infection. Many RNA viruses are potent activators of complement, often resulting in virus neutralization. Yet, another facet of virus-induced activation is the exacerbation in pathogenesis contributing to the overall morbidity. The severity in disease and death associated with RNA virus infections shows a tip in the scale favoring viruses. Growing evidence suggest that like their DNA counterparts, RNA viruses have co-evolved to master ingenious strategies to remarkably restrict complement. Modulation of host genes involved in antiviral responses contributed prominently to the adoption of unique strategies to keep complement at bay, which included either down regulation of activation components (C3, C4) or up regulation of complement regulatory proteins. All this hints at a possible “hijacking” of the cross-talk mechanism of the host immune system. Enveloped RNA viruses have a selective advantage of not only modulating the host responses but also recruiting membrane-associated regulators of complement activation (RCAs). This review aims to highlight the significant progress in the understanding of RNA virus–complement interactions.
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Affiliation(s)
- Nisha Asok Kumar
- Viral Disease Biology, Department of Pathogen Biology, Rajiv Gandhi Center for Biotechnology, Thiruvananthapuram, India.,Manipal Academy of Higher Education, Manipal, India
| | - Umerali Kunnakkadan
- Viral Disease Biology, Department of Pathogen Biology, Rajiv Gandhi Center for Biotechnology, Thiruvananthapuram, India.,Department of Biotechnology, University of Kerala, Thiruvananthapuram, India
| | - Sabu Thomas
- Cholera and Biofilm Research Lab, Department of Pathogen Biology, Rajiv Gandhi Center for Biotechnology, Thiruvananthapuram, India
| | - John Bernet Johnson
- Viral Disease Biology, Department of Pathogen Biology, Rajiv Gandhi Center for Biotechnology, Thiruvananthapuram, India
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4
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Elahi S, Mashhouri S. Immunological consequences of extramedullary erythropoiesis: immunoregulatory functions of CD71 + erythroid cells. Haematologica 2020; 105:1478-1483. [PMID: 32354873 PMCID: PMC7271582 DOI: 10.3324/haematol.2019.243063] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 04/06/2020] [Indexed: 12/22/2022] Open
Affiliation(s)
- Shokrollah Elahi
- School of Dentistry, University of Alberta, Alberta .,Department of Medical Microbiology and Immunology, University of Alberta, Alberta.,Department of Medical Oncology, Faculty of Medicine and Dentistry, University of Alberta, Alberta.,Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta, Canada
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5
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Lukácsi S, Mácsik-Valent B, Nagy-Baló Z, Kovács KG, Kliment K, Bajtay Z, Erdei A. Utilization of complement receptors in immune cell-microbe interaction. FEBS Lett 2020; 594:2695-2713. [PMID: 31989596 DOI: 10.1002/1873-3468.13743] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/15/2020] [Accepted: 01/16/2020] [Indexed: 12/19/2022]
Abstract
The complement system is a major humoral component of immunity and is essential for the fast elimination of pathogens invading the body. In addition to its indispensable role in innate immunity, the complement system is also involved in pathogen clearance during the effector phase of adaptive immunity. The fastest way of killing the invader is lysis by the membrane attack complex, which is formed by the terminal components of the complement cascade. Not all pathogens are lysed however and, if opsonized by a variety of molecules, they undergo phagocytosis and disposal inside immune cells. The most important complement-derived opsonins are C1q, the first component of the classical pathway, MBL, the initiator of the lectin pathway and C3-derived activation fragments, including C3b, iC3b and C3d, which all serve as ligands for their corresponding receptors. In this review, we discuss how complement receptors are utilized by various immune cells to tackle invading microbes, or by pathogens to evade host response.
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Affiliation(s)
- Szilvia Lukácsi
- MTA-ELTE Immunology Research Group, Eötvös Loránd University, Budapest, Hungary
| | | | - Zsuzsa Nagy-Baló
- Department of Immunology, Eötvös Loránd University, Budapest, Hungary
| | - Kristóf G Kovács
- Department of Immunology, Eötvös Loránd University, Budapest, Hungary
| | | | - Zsuzsa Bajtay
- MTA-ELTE Immunology Research Group, Eötvös Loránd University, Budapest, Hungary.,Department of Immunology, Eötvös Loránd University, Budapest, Hungary
| | - Anna Erdei
- MTA-ELTE Immunology Research Group, Eötvös Loránd University, Budapest, Hungary.,Department of Immunology, Eötvös Loránd University, Budapest, Hungary
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6
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Perez LG, Martinez DR, deCamp AC, Pinter A, Berman PW, Francis D, Sinangil F, Lee C, Greene K, Gao H, Nitayaphan S, Rerks-Ngarm S, Kaewkungwal J, Pitisuttithum P, Tartaglia J, O’Connell RJ, Robb ML, Michael NL, Kim JH, Gilbert P, Montefiori DC. V1V2-specific complement activating serum IgG as a correlate of reduced HIV-1 infection risk in RV144. PLoS One 2017; 12:e0180720. [PMID: 28678869 PMCID: PMC5498072 DOI: 10.1371/journal.pone.0180720] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 06/20/2017] [Indexed: 12/18/2022] Open
Abstract
Non-neutralizing IgG to the V1V2 loop of HIV-1 gp120 correlates with a decreased risk of HIV-1 infection but the mechanism of protection remains unknown. This V1V2 IgG correlate was identified in RV144 Thai trial vaccine recipients, who were primed with a canarypox vector expressing membrane-bound gp120 (vCP1521) and boosted with vCP1521 plus a mixture gp120 proteins from clade B and clade CRF01_AE (B/E gp120). We sought to determine whether the mechanism of vaccine protection might involve antibody-dependent complement activation. Complement activation was measured as a function of complement component C3d deposition on V1V2-coated beads in the presence of RV144 sera. Variable levels of complement activation were detected two weeks post final boosting in RV144, which is when the V1V2 IgG correlate was identified. The magnitude of complement activation correlated with V1V2-specific serum IgG and was stronger and more common in RV144 than in HIV-1 infected individuals and two related HIV-1 vaccine trials, VAX003 and VAX004, where no protection was seen. After adjusting for gp120 IgA, V1V2 IgG, gender, and risk score, complement activation by case-control plasmas from RV144 correlated inversely with a reduced risk of HIV-1 infection, with odds ratio for positive versus negative response to TH023-V1V2 0.42 (95% CI 0.18 to 0.99, p = 0.048) and to A244-V1V2 0.49 (95% CI 0.21 to 1.10, p = 0.085). These results suggest that complement activity may have contributed in part to modest protection against the acquisition of HIV-1 infection seen in the RV144 trial.
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Affiliation(s)
- Lautaro G. Perez
- Duke University Medical Center, Durham, North Carolina, United States of America
| | - David R. Martinez
- Duke University Medical Center, Durham, North Carolina, United States of America
| | - Allan C. deCamp
- Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Abraham Pinter
- Public Health Research Institute, Newark, New Jersey, United States of America
| | - Phillip W. Berman
- Baskin School of Engineering, University of California, Santa Cruz, California, United States of America
| | - Donald Francis
- Global Solutions for Infectious Diseases, South San Francisco, California, United States of America
| | - Faruk Sinangil
- Global Solutions for Infectious Diseases, South San Francisco, California, United States of America
| | - Carter Lee
- Global Solutions for Infectious Diseases, South San Francisco, California, United States of America
| | - Kelli Greene
- Duke University Medical Center, Durham, North Carolina, United States of America
| | - Hongmei Gao
- Duke University Medical Center, Durham, North Carolina, United States of America
| | | | | | | | | | - James Tartaglia
- Department of Research and Development, Sanofi Pasteur, Swiftwater, Pennsylvania, United States of America
| | - Robert J. O’Connell
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
- Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Merlin L. Robb
- Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Nelson L. Michael
- Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Jerome H. Kim
- International Vaccine Institute, Seoul, Republic of Korea
| | - Peter Gilbert
- Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - David C. Montefiori
- Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
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7
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Avirutnan P, Mehlhop E, Diamond MS. Complement and its role in protection and pathogenesis of flavivirus infections. Vaccine 2009; 26 Suppl 8:I100-7. [PMID: 19388173 PMCID: PMC2768071 DOI: 10.1016/j.vaccine.2008.11.061] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The complement system is a family of serum and cell surface proteins that recognize pathogen-associated molecular patterns, altered-self ligands, and immune complexes. Activation of the complement cascade triggers several antiviral functions including pathogen opsonization and/or lysis, and priming of adaptive immune responses. In this review, we will examine the role of complement activation in protection and/or pathogenesis against infection by Flaviviruses, with an emphasis on experiments with West Nile and Dengue viruses.
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Affiliation(s)
- Panisadee Avirutnan
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, United States
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8
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Khera R, Das N. Complement Receptor 1: disease associations and therapeutic implications. Mol Immunol 2008; 46:761-72. [PMID: 19004497 PMCID: PMC7125513 DOI: 10.1016/j.molimm.2008.09.026] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 09/15/2008] [Accepted: 09/15/2008] [Indexed: 11/17/2022]
Abstract
Exaggerated complement activation is a key event in the pathogenesis of a range of autoimmune and inflammatory diseases. Complement Receptor 1 (CR1) has emerged as a molecule of immense interest in gaining insight to the susceptibility, pathophysiology, diagnosis, prognosis and therapy of such diseases. This review brings forth a composite view of the current understanding on the structure, functions, genetics, disease associations and therapeutic implications of CR1.
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Affiliation(s)
- Rohan Khera
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi 110029, India
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9
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Complement-HIV interactions during all steps of viral pathogenesis. Vaccine 2007; 26:3046-54. [PMID: 18191309 DOI: 10.1016/j.vaccine.2007.12.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Revised: 11/27/2007] [Accepted: 12/01/2007] [Indexed: 01/24/2023]
Abstract
Upon crossing the endothelial barrier of the host, HIV initiates immediate responses of the immunity system. Among its components, the complement system is one of the first the first elements, which are activated to affect HIV propagation. Complement participates not only in the early phase of the immune response, but its effects can be observed continuously and also concern the induction and modification of the adaptive immune response. Here we discuss the role of complement in early and late stages of HIV pathogenesis and review the escape mechanisms, which protect HIV from destruction by the complement system.
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10
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Fierer DS, Vargas J, Patel N, Clover G. Absence of erythrocyte-associated HIV-1 in vivo. J Infect Dis 2007; 196:587-90. [PMID: 17624845 PMCID: PMC1950676 DOI: 10.1086/519741] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2006] [Accepted: 03/12/2007] [Indexed: 11/03/2022] Open
Abstract
A recent study found high levels of human immunodeficiency virus type 1 (HIV-1) bound to erythrocytes in HIV-1-infected patients with long-term undetectable plasma HIV-1 loads, potentially representing a novel and important reservoir of HIV-1 infection. To attempt to confirm this finding, we purified erythrocytes from 13 HIV-1-infected patients with long-term undetectable plasma viral load and depleted contaminating CD3(+)CD4(+) lymphocytes using magnetic beads. HIV-1 load of the purified erythrocyte fraction was <20 copies/mL in 11 of 13 patients and 42 and 52 copies/mL in 2 patients. Contrary to the prior report, therefore, erythrocytes do not represent a novel reservoir of HIV-1 infection in these patients.
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Affiliation(s)
- Daniel Seth Fierer
- Division of Infectious Diseases, Mount Sinai School of Medicine, New York, NY 10029, USA.
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11
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Bánki Z, Wilflingseder D, Ammann CG, Pruenster M, Müllauer B, Holländer K, Meyer M, Sprinzl GM, van Lunzen J, Stellbrink HJ, Dierich MP, Stoiber H. Factor I-mediated processing of complement fragments on HIV immune complexes targets HIV to CR2-expressing B cells and facilitates B cell-mediated transmission of opsonized HIV to T cells. THE JOURNAL OF IMMUNOLOGY 2006; 177:3469-76. [PMID: 16920989 DOI: 10.4049/jimmunol.177.5.3469] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Our study demonstrates that binding of complement-opsonized HIV to complement receptor type 1 on human erythrocytes (E) via C3b fragments is followed by a rapid normal human serum-mediated detachment of HIV from E. The release was dependent on the presence of factor I indicating a conversion of C3b fragments to iC3b and C3d on the viral surface. This in turn resulted in an efficient binding of opsonized HIV to CR2-expressing B cells, thus facilitating B cell-mediated transmission of HIV to T cells. These data provide a new dynamic view of complement opsonization of HIV, suggesting that association of virus with E might be a transient phenomenon and the factor I-mediated processing of C3b to iC3b and C3d on HIV targets the virus to complement receptor type 2-expressing cells. Thus, factor I in concert with CR1 on E and factor H in serum due to their cofactor activity are likely to be important contributors for the generation of C3d-opsonized infectious HIV reservoirs on follicular dendritic cells and/or B cells in HIV-infected individuals.
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Affiliation(s)
- Zoltán Bánki
- Department of Hygiene, Microbiology and Social Medicine, Innsbruck Medical University, Austria.
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12
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Sadallah S, Heim M, Hess C, Klimkait T, Battegay M, Schifferli JA. Contrary to HIV, hepatitis C virus is not associated with erythrocytes in vivo. J Hepatol 2005; 42:150-2. [PMID: 15629525 DOI: 10.1016/j.jhep.2004.07.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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13
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Bánki Z, Stoiber H, Dierich MP. HIV and human complement: inefficient virolysis and effective adherence. Immunol Lett 2004; 97:209-14. [PMID: 15752560 DOI: 10.1016/j.imlet.2004.11.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2004] [Revised: 11/08/2004] [Accepted: 11/08/2004] [Indexed: 02/02/2023]
Abstract
Both, HIV envelope proteins gp120 and gp41 can directly activate complement system, even in the absence of HIV-specific antibodies. During the budding process HIV acquires host membrane-associated molecules among these complement regulatory proteins (CRPs). The presence of CRPs on the viral surface rescues HIV from complement-mediated virolysis. The inefficient virolysis results in the deposition of complement-fragments on the viral surface allowing interactions of HIV with complement receptor expressing cells. In this review, the interaction of HIV with the complement system and the consequences of complement opsonisation on virus infection will be discussed.
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Affiliation(s)
- Zoltán Bánki
- Department of Hygiene, Microbiology and Social Medicine, Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria and Ludwig-Boltzmann-Institute for AIDS research, Fritz-Pregl-Str. 3., 6020 Innsbruck, Austria
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14
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Horakova E, Gasser O, Sadallah S, Inal JM, Bourgeois G, Ziekau I, Klimkait T, Schifferli JA. Complement Mediates the Binding of HIV to Erythrocytes. THE JOURNAL OF IMMUNOLOGY 2004; 173:4236-41. [PMID: 15356175 DOI: 10.4049/jimmunol.173.6.4236] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A fraction of HIV is associated with erythrocytes even when the virus becomes undetectable in plasma under antiretroviral therapy. The aim of the present work was to further characterize this association in vitro. We developed an in vitro model to study the factors involved in the adherence of HIV-1 to erythrocytes. Radiolabeled HIV-1 (HIV) and preformed HIV-1/anti-HIV immune complexes (HIV-IC) were opsonized in various human sera, purified using sucrose density gradient ultracentrifugation, and incubated with human erythrocytes. We observed that, when opsonized in normal human serum, not only HIV-IC, but also HIV, bound to erythrocytes, although the adherence of HIV was lower than that of HIV-IC. The adherence was abolished when the complement system was blocked, but was maintained in hypogammaglobulinemic sera. Complement-deficient sera indicated that both pathways of complement were important for optimal adherence. No adherence was seen in C1q-deficient serum, and the adherence of HIV was reduced when the alternative pathway was blocked using anti-factor D Abs. The adherence could be inhibited by an mAb against complement receptor 1. At supraphysiological concentrations, purified C1q mediated the binding of a small fraction of HIV and HIV-IC to erythrocytes. In conclusion, HIV-IC bound to erythrocytes as other types of IC do when exposed to complement. Of particular interest was that HIV alone bound also to erythrocytes in a complement/complement receptor 1-dependent manner. Thus, erythrocytes may not only deliver HIV-IC to organs susceptible to infection, but free HIV as well. This may play a crucial role in the progression of the primary infection.
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Affiliation(s)
- Eliska Horakova
- Laboratory of Immunonephrology, Department of Research, and University of Basel, Switzerland
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15
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Garber DA, Silvestri G, Barry AP, Fedanov A, Kozyr N, McClure H, Montefiori DC, Larsen CP, Altman JD, Staprans SI, Feinberg MB. Blockade of T cell costimulation reveals interrelated actions of CD4+ and CD8+ T cells in control of SIV replication. J Clin Invest 2004. [DOI: 10.1172/jci200419442] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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16
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Garber DA, Silvestri G, Barry AP, Fedanov A, Kozyr N, McClure H, Montefiori DC, Larsen CP, Altman JD, Staprans SI, Feinberg MB. Blockade of T cell costimulation reveals interrelated actions of CD4+ and CD8+ T cells in control of SIV replication. J Clin Invest 2004; 113:836-45. [PMID: 15067316 PMCID: PMC362114 DOI: 10.1172/jci19442] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2003] [Accepted: 12/16/2003] [Indexed: 11/17/2022] Open
Abstract
In vivo blockade of CD28 and CD40 T cell costimulation pathways during acute simian immunodeficiency virus (SIV) infection of rhesus macaques was performed to assess the relative contributions of CD4+ T cells, CD8+ T cells, and Ab responses in modulating SIV replication and disease progression. Transient administration of CTLA4-Ig and anti-CD40L mAb to SIV-infected rhesus macaques resulted in dramatic inhibition of the generation of both SIV-specific cellular and humoral immune responses. Acute levels of proliferating CD8+ T cells were associated with early control of SIV viremia but did not predict ensuing set point viremia or survival. The level of in vivo CD4+ T cell proliferation during acute SIV infection correlated with concomitant peak levels of SIV plasma viremia, whereas measures of in vivo CD4+ T cell proliferation that extended into chronic infection correlated with lower SIV viral load and increased survival. These results suggest that proliferating CD4+ T cells function both as sources of virus production and as antiviral effectors and that increased levels of CD4+ T cell proliferation during SIV infections reflect antigen-driven antiviral responses rather than a compensatory homeostatic response. These results highlight the interrelated actions of CD4+ and CD8+ T cell responses in vivo that modulate SIV replication and pathogenesis.
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Abstract
Erythrocytes bind immune complexes (ICs) composed of antibodies binding their respective antigen (e.g., bacteria, parasites, viruses, or autoantigen) plus complement proteins via complement receptors [immune adherence (IA)]. In vivo studies have shown that erythrocytes act as an inert shuttle, targeting ICs to fixed macrophages in liver and spleen. Here we outline established and emerging implications of IA in health and disease.
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Affiliation(s)
- Christoph Hess
- Department of Medicine, Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital/Harvard Medical School, Charlestown, Massachusetts 02129, USA
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18
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Hess C, Klimkait T, Schlapbach L, Del Zenero V, Sadallah S, Horakova E, Balestra G, Werder V, Schaefer C, Battegay M, Schifferli JA. Association of a pool of HIV-1 with erythrocytes in vivo: a cohort study. Lancet 2002; 359:2230-4. [PMID: 12103286 DOI: 10.1016/s0140-6736(02)09291-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND Treatment of HIV-1-infected individuals with antiretrovirals can result in sustained suppression of plasma viral RNA at concentrations below the detection limit of available assays. However, continuing virus replication has been detected in patients with viral RNA in plasma suppressed for months to years, and many cell types are known to act as reservoirs or carriers for the virus. In vitro, erythrocytes bind HIV-1 immune complexes, so we tested for a circulating pool of HIV-1 associated with erythrocytes in people with HIV-1 infection. METHODS We investigated 82 chronically HIV-1-infected individuals. Plasma, white cells, and erythrocytes were tested for HIV-1 RNA by RT-PCR. FINDINGS Erythrocyte-associated HIV-1 RNA was detected in 80 of 82 individuals. In 23, plasma HIV-1 RNA had been undetectable (<20 copies/mL) for up to 32 months; in corresponding erythrocyte samples, there were up to 82878 HIV-1 RNA copies per mL whole blood. HIV-1 associated with erythrocytes in vivo was shown to be infectious. Within the subgroup of patients with undetectable plasma viral load, higher numbers of HIV-1 associated with erythrocytes were correlated with a history of advanced clinical stages of HIV-1 infection (p=0.014). INTERPRETATION A pool of HIV-1 is associated with erythrocytes even after long-term suppression of viral RNA in plasma. This finding is direct evidence for continuing virus replication or release in these individuals. Quantification of this viral pool may help to judge suppression of HIV-1 replication in individuals with undetectable plasma HIV-1 RNA.
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Affiliation(s)
- Christoph Hess
- Department of Research, Immunonephrology Laboratory, University Hospital Basel, Basel, Switzerland.
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19
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Schmitz JE, Lifton MA, Reimann KA, Montefiori DC, Shen L, Racz P, Tenner-Racz K, Ollert MW, Forman MA, Gelman RS, Vogel CW, Letvin NL. Effect of complement consumption by cobra venom factor on the course of primary infection with simian immunodeficiency virus in rhesus monkeys. AIDS Res Hum Retroviruses 1999; 15:195-202. [PMID: 10029251 DOI: 10.1089/088922299311619] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cobra venom factor (CVF)-induced consumption of complement proteins was used to investigate the role of complement in vivo in the immunopathogenesis of simian immunodeficiency virus of macaques (SIVmac) infection in rhesus monkeys. Repeated administration of CVF was shown to deplete complement to <5% of baseline hemolytic activity of serum complement for 10 days in a normal monkey. Three groups of SIVmac-infected animals were then evaluated: monkeys treated with CVF resulting in complement depletion from days -1 to 10 postinfection, monkeys treated with CVF resulting in complement depletion from days 10 to 21 postinfection, and control monkeys that received no CVF. CD8+ SIVmac-specific cytotoxic T lymphocyte (CTL) generation and CD4+ T lymphocyte depletion during primary infection were not affected by CVF treatment. Viral load, assessed by measurements of plasma p27gag antigen and viral RNA, was transiently higher during the first 4 weeks following infection in the CVF-treated monkeys and the subsequent clinical course in these treated animals was accelerated. These results suggest that complement proteins may participate in immune defense mechanisms that decrease virus replication following the initial burst of intense viremia during primary SIVmac infection. However, we cannot rule out that the observed increased virus replication was induced by immune activation resulting from the administration of a foreign antigen to these monkeys.
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Affiliation(s)
- J E Schmitz
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
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20
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Abstract
In the recent years, advances in biochemistry and molecular genetics have contributed to establish the structure of the genes and proteins from most of the 23 blood group systems presently known. From these findings, five functional classes of molecules can be schematically distinguished: (i) transporters and channels, (ii) receptors for ligands, viruses, bacteria and parasites, (iii) adhesion molecules, (iv) enzymes, and (v) structural proteins. Recent advances on these molecules will be reviewed, particularly by illustrating available structure-function relationships.
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Affiliation(s)
- J P Cartron
- INSERM U76 et Institut national de la transfusion sanguine, Paris, France
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Affiliation(s)
- S Lu
- Department of Medicine, University of Massachusetts Medical Center, Worcester 01655, USA
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22
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Montefiori DC. Role of complement and Fc receptors in the pathogenesis of HIV-1 infection. SPRINGER SEMINARS IN IMMUNOPATHOLOGY 1997; 18:371-90. [PMID: 9089955 DOI: 10.1007/bf00813504] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- D C Montefiori
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
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23
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Reimann KA, Li JT, Voss G, Lekutis C, Tenner-Racz K, Racz P, Lin W, Montefiori DC, Lee-Parritz DE, Lu Y, Collman RG, Sodroski J, Letvin NL. An env gene derived from a primary human immunodeficiency virus type 1 isolate confers high in vivo replicative capacity to a chimeric simian/human immunodeficiency virus in rhesus monkeys. J Virol 1996; 70:3198-206. [PMID: 8627800 PMCID: PMC190183 DOI: 10.1128/jvi.70.5.3198-3206.1996] [Citation(s) in RCA: 211] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
To explore the roles played by specific human immunodeficiency virus type 1 (HIV-1) genes in determining the in vivo replicative capacity of AIDS viruses, we have examined the replication kinetics and virus-specific immune responses in rhesus monkeys following infection with two chimeric simian/human immunodeficiency viruses (SHIVs). These viruses were composed of simian immunodeficiency virus SIVmac239 expressing HIV-1 env and the associated auxiliary HIV-1 genes tat, vpu, and rep. Virus replication was assessed during primary infection of rhesus monkeys by measuring plasma SIVmac p27 levels and by quantifying virus replication in lymph nodes using in situ hybridization. SHIV-HXBc2, which expresses the HIV-1 env of a T-cell-tropic, laboratory-adapted strain of HIV-1 (HXBc2), replicated well in rhesus monkey peripheral blood leukocytes (PBL) in vitro but replicated only to low levels when inoculated in rhesus monkeys. In contrast, SHIV-89.6 was constructed with the HIV-1 env gene of a T-cell- and macrophage-tropic clone of a patient isolate of HIV-1 (89.6). This virus replicated to a lower level in monkey PBL in vitro but replicated to a higher degree in monkeys during primary infection. Moreover, monkeys infected with SHIV-89.6 developed an inversion in the PBL CD4/CD8 ratio coincident with the clearance of primary viremia. The differences in the in vivo consequences of infection by these two SHIVs could not be explained by differences in the immune responses elicited by these viruses, since infected animals had comparable type-specific neutralizing antibody titers, proliferative responses to recombinant HIV-1 gp120, and virus-specific cytolytic effector T-cell responses. With the demonstration that a chimeric SHIV can replicate to high levels during primary infection in rhesus monkeys, this model can now be used to define genetic determinants of HIV-1 pathogenicity.
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Affiliation(s)
- K A Reimann
- Division of Viral Pathogenesis, Beth Israel Hospital, Boston, Massachusetts 02115, USA
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Montefiori DC, Reimann KA, Letvin NL, Zhou J, Hu SL. Studies of complement-activating antibodies in the SIV/macaque model of acute primary infection and vaccine protection. AIDS Res Hum Retroviruses 1995; 11:963-70. [PMID: 7492443 DOI: 10.1089/aid.1995.11.963] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Questions regarding the potential impact of complement-activating antibodies on lentivirus pathogenesis and vaccine development were addressed in the SIV/macaque model by evaluating sera for activity related to complement-mediated, antibody-dependent enhancement (C'-ADE) of SIV infection in vitro. C'-ADE activity in sera obtained during acute primary infection in macaques inoculated with SIVmac251 appeared before neutralizing antibodies and coincided with the initial peak and decline of plasma antigenemia. The power of C'-ADE activity (i.e., virus production measured by p24 immunoassay) decreased as titers of neutralizing antibodies increased in these animals, suggesting a balance in the net effect between C'-ADE and neutralizing activities in vitro. Antibodies with C'-ADE activity were also induced in macaques immunized with live-attenuated SIVmac239/nef-deletion or primed with recombinant SIVmne gp120 vaccinia virus and boosted with SIVmne rgp160. The titer (i.e., last serum dilution to show enhancement), peak (i.e., serum dilution producing the greatest enhancement as measured by p24 production), and power (i.e., magnitude of p24 production at the peak titer) of C'-ADE activity in sera obtained from vaccinated macaques on the day of challenge were comparable to those of sera from infected macaques and showed no correlation with vaccine outcome, where some protected animals had C'-ADE profiles that resembled those of unprotected animals. The results of these studies suggest that antibodies having C'-ADE activity in vitro could contribute to virus replication or, alternatively, to virus clearance during the acute stage of SIV infection in macaques.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- D C Montefiori
- Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
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