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Avdonin PP, Blinova MS, Generalova GA, Emirova KM, Avdonin PV. The Role of the Complement System in the Pathogenesis of Infectious Forms of Hemolytic Uremic Syndrome. Biomolecules 2023; 14:39. [PMID: 38254639 PMCID: PMC10813406 DOI: 10.3390/biom14010039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 11/24/2023] [Accepted: 12/18/2023] [Indexed: 01/24/2024] Open
Abstract
Hemolytic uremic syndrome (HUS) is an acute disease and the most common cause of childhood acute renal failure. HUS is characterized by a triad of symptoms: microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. In most of the cases, HUS occurs as a result of infection caused by Shiga toxin-producing microbes: hemorrhagic Escherichia coli and Shigella dysenteriae type 1. They account for up to 90% of all cases of HUS. The remaining 10% of cases grouped under the general term atypical HUS represent a heterogeneous group of diseases with similar clinical signs. Emerging evidence suggests that in addition to E. coli and S. dysenteriae type 1, a variety of bacterial and viral infections can cause the development of HUS. In particular, infectious diseases act as the main cause of aHUS recurrence. The pathogenesis of most cases of atypical HUS is based on congenital or acquired defects of complement system. This review presents summarized data from recent studies, suggesting that complement dysregulation is a key pathogenetic factor in various types of infection-induced HUS. Separate links in the complement system are considered, the damage of which during bacterial and viral infections can lead to complement hyperactivation following by microvascular endothelial injury and development of acute renal failure.
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Affiliation(s)
- Piotr P. Avdonin
- Koltzov Institute of Developmental Biology RAS, ul. Vavilova, 26, 119334 Moscow, Russia; (M.S.B.); (P.V.A.)
| | - Maria S. Blinova
- Koltzov Institute of Developmental Biology RAS, ul. Vavilova, 26, 119334 Moscow, Russia; (M.S.B.); (P.V.A.)
| | - Galina A. Generalova
- Saint Vladimir Moscow City Children’s Clinical Hospital, 107014 Moscow, Russia; (G.A.G.); (K.M.E.)
- Department of Pediatrics, A.I. Evdokimov Moscow State University of Medicine and Dentistry, 127473 Moscow, Russia
| | - Khadizha M. Emirova
- Saint Vladimir Moscow City Children’s Clinical Hospital, 107014 Moscow, Russia; (G.A.G.); (K.M.E.)
- Department of Pediatrics, A.I. Evdokimov Moscow State University of Medicine and Dentistry, 127473 Moscow, Russia
| | - Pavel V. Avdonin
- Koltzov Institute of Developmental Biology RAS, ul. Vavilova, 26, 119334 Moscow, Russia; (M.S.B.); (P.V.A.)
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2
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Bertacchi G, Posch W, Wilflingseder D. HIV-1 Trans Infection via TNTs Is Impeded by Targeting C5aR. Biomolecules 2022; 12:biom12020313. [PMID: 35204813 PMCID: PMC8868603 DOI: 10.3390/biom12020313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/03/2022] [Accepted: 02/10/2022] [Indexed: 02/04/2023] Open
Abstract
Nonadjacent immune cells communicate through a complex network of tunneling nanotubes (TNTs). TNTs can be hijacked by HIV-1, allowing it to spread between connected cells. Dendritic cells (DCs) are among the first cells to encounter HIV-1 at mucosal sites, but they are usually efficiently infected only at low levels. However, HIV-1 was demonstrated to productively infect DCs when the virus was complement-opsonized (HIV-C). Such HIV-C-exposed DCs mediated an improved antiviral and T-cell stimulatory capacity. The role of TNTs in combination with complement in enhancing DC infection with HIV-C remains to be addressed. To this aim, we evaluated TNT formation on the surface of DCs or DC/CD4+ T-cell co-cultures incubated with non- or complement-opsonized HIV-1 (HIV, HIV-C) and the role of TNTs or locally produced complement in the infection process using either two different TNT or anaphylatoxin receptor antagonists. We found that HIV-C significantly increased the formation of TNTs between DCs or DC/CD4+ T-cell co-cultures compared to HIV-exposed DCs or co-cultures. While augmented TNT formation in DCs promoted productive infection, as was previously observed, a significant reduction in productive infection was observed in DC/CD4+ T-cell co-cultures, indicating antiviral activity in this setting. As expected, TNT inhibitors significantly decreased infection of HIV-C-loaded-DCs as well as HIV- and HIV-C-infected-DC/CD4+ T-cell co-cultures. Moreover, antagonizing C5aR significantly inhibited TNT formation in DCs as well as DC/CD4+ T-cell co-cultures and lowered the already decreased productive infection in co-cultures. Thus, local complement mobilization via DC stimulation of complement receptors plays a pivotal role in TNT formation, and our findings herein might offer an exciting opportunity for novel therapeutic approaches to inhibit trans infection via C5aR targeting.
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3
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Abstract
Complement-opsonized HIV-1 triggers efficient antiviral type I interferon (IFN) responses in dendritic cells (DCs), which play an important role in protective responses at the earliest stages in retroviral infection. In contrast, HIV-1 suppresses or escapes sensing by STING- and MAVS-associated sensors. Here, we identified a complement receptor-mediated sensing pathway, where DCs are activated in CCR5/RLR (RIG-I/MDA5)/MAVS/TBK1-dependent fashion. Increased fusion of complement-opsonized HIV-1 via complement receptor 4 and CCR5 leads to increased incoming HIV-1 RNA in the cytoplasm, sensed by a nonredundant cooperative effect of RIG-I and MDA5. Moreover, complement-opsonized HIV-1 down-modulated the MAVS-suppressive Raf-1/PLK1 pathway, thereby opening the antiviral recognition pathway via MAVS. This in turn was followed by MAVS aggregation and subsequent TBK1/IRF3/NF-κB activation in DCs exposed to complement- but not non-opsonized HIV-1. Our data strongly suggest that complement is important in the induction of efficient antiviral immune responses by preventing HIV-1 suppressive mechanisms as well as inducing specific cytosolic sensors.
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4
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Syed I, Wooten RM. Interactions Between Pathogenic Burkholderia and the Complement System: A Review of Potential Immune Evasion Mechanisms. Front Cell Infect Microbiol 2021; 11:701362. [PMID: 34660335 PMCID: PMC8515183 DOI: 10.3389/fcimb.2021.701362] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 09/15/2021] [Indexed: 12/12/2022] Open
Abstract
The genus Burkholderia contains over 80 different Gram-negative species including both plant and human pathogens, the latter of which can be classified into one of two groups: the Burkholderia pseudomallei complex (Bpc) or the Burkholderia cepacia complex (Bcc). Bpc pathogens Burkholderia pseudomallei and Burkholderia mallei are highly virulent, and both have considerable potential for use as Tier 1 bioterrorism agents; thus there is great interest in the development of novel vaccines and therapeutics for the prevention and treatment of these infections. While Bcc pathogens Burkholderia cenocepacia, Burkholderia multivorans, and Burkholderia cepacia are not considered bioterror threats, the incredible impact these infections have on the cystic fibrosis community inspires a similar demand for vaccines and therapeutics for the prevention and treatment of these infections as well. Understanding how these pathogens interact with and evade the host immune system will help uncover novel therapeutic targets within these organisms. Given the important role of the complement system in the clearance of bacterial pathogens, this arm of the immune response must be efficiently evaded for successful infection to occur. In this review, we will introduce the Burkholderia species to be discussed, followed by a summary of the complement system and known mechanisms by which pathogens interact with this critical system to evade clearance within the host. We will conclude with a review of literature relating to the interactions between the herein discussed Burkholderia species and the host complement system, with the goal of highlighting areas in this field that warrant further investigation.
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Affiliation(s)
- Irum Syed
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
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5
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Nijmeijer BM, Bermejo-Jambrina M, Kaptein TM, Ribeiro CMS, Wilflingseder D, Geijtenbeek TBH. HIV-1 subverts the complement system in semen to enhance viral transmission. Mucosal Immunol 2021; 14:743-750. [PMID: 33568786 PMCID: PMC8075950 DOI: 10.1038/s41385-021-00376-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 12/13/2020] [Accepted: 01/04/2021] [Indexed: 02/04/2023]
Abstract
Semen is important in determining HIV-1 susceptibility but it is unclear how it affects virus transmission during sexual contact. Mucosal Langerhans cells (LCs) are the first immune cells to encounter HIV-1 during sexual contact and have a barrier function as LCs are restrictive to HIV-1. As semen from people living with HIV-1 contains complement-opsonized HIV-1, we investigated the effect of complement on HIV-1 dissemination by human LCs in vitro and ex vivo. Notably, pre-treatment of HIV-1 with semen enhanced LC infection compared to untreated HIV-1 in the ex vivo explant model. Infection of LCs and transmission to target cells by opsonized HIV-1 was efficiently inhibited by blocking complement receptors CR3 and CR4. Complement opsonization of HIV-1 enhanced uptake, fusion, and integration by LCs leading to an increased transmission of HIV-1 to target cells. However, in the absence of both CR3 and CR4, C-type lectin receptor langerin was able to restrict infection of complement-opsonized HIV-1. These data suggest that complement enhances HIV-1 infection of LCs by binding CR3 and CR4, thereby bypassing langerin and changing the restrictive nature of LCs into virus-disseminating cells. Targeting complement factors might be effective in preventing HIV-1 transmission.
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Affiliation(s)
- Bernadien M Nijmeijer
- Department of Experimental Immunology, Amsterdam Infection and Immunity Institute, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, the Netherlands
| | - Marta Bermejo-Jambrina
- Department of Experimental Immunology, Amsterdam Infection and Immunity Institute, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, the Netherlands
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Tanja M Kaptein
- Department of Experimental Immunology, Amsterdam Infection and Immunity Institute, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, the Netherlands
| | - Carla M S Ribeiro
- Department of Experimental Immunology, Amsterdam Infection and Immunity Institute, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, the Netherlands
| | - Doris Wilflingseder
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria.
| | - Teunis B H Geijtenbeek
- Department of Experimental Immunology, Amsterdam Infection and Immunity Institute, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, the Netherlands.
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6
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Syed I, Wooten RM. Interactions Between Pathogenic Burkholderia and the Complement System: A Review of Potential Immune Evasion Mechanisms. Front Cell Infect Microbiol 2021. [PMID: 34660335 DOI: 10.1086/69216810.3389/fcimb.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023] Open
Abstract
The genus Burkholderia contains over 80 different Gram-negative species including both plant and human pathogens, the latter of which can be classified into one of two groups: the Burkholderia pseudomallei complex (Bpc) or the Burkholderia cepacia complex (Bcc). Bpc pathogens Burkholderia pseudomallei and Burkholderia mallei are highly virulent, and both have considerable potential for use as Tier 1 bioterrorism agents; thus there is great interest in the development of novel vaccines and therapeutics for the prevention and treatment of these infections. While Bcc pathogens Burkholderia cenocepacia, Burkholderia multivorans, and Burkholderia cepacia are not considered bioterror threats, the incredible impact these infections have on the cystic fibrosis community inspires a similar demand for vaccines and therapeutics for the prevention and treatment of these infections as well. Understanding how these pathogens interact with and evade the host immune system will help uncover novel therapeutic targets within these organisms. Given the important role of the complement system in the clearance of bacterial pathogens, this arm of the immune response must be efficiently evaded for successful infection to occur. In this review, we will introduce the Burkholderia species to be discussed, followed by a summary of the complement system and known mechanisms by which pathogens interact with this critical system to evade clearance within the host. We will conclude with a review of literature relating to the interactions between the herein discussed Burkholderia species and the host complement system, with the goal of highlighting areas in this field that warrant further investigation.
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Affiliation(s)
- Irum Syed
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - R Mark Wooten
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
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7
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Abstract
The innate immune system is comprised of both cellular and humoral players that recognise and eradicate invading pathogens. Therefore, the interplay between retroviruses and innate immunity has emerged as an important component of viral pathogenesis. HIV-1 infection in humans that results in hematologic abnormalities and immune suppression is well represented by changes in the CD4/CD8 T cell ratio and consequent cell death causing CD4 lymphopenia. The innate immune responses by mucosal barriers such as complement, DCs, macrophages, and NK cells as well as cytokine/chemokine profiles attain great importance in acute HIV-1 infection, and thus, prevent mucosal capture and transmission of HIV-1. Conversely, HIV-1 has evolved to overcome innate immune responses through RNA-mediated rapid mutations, pathogen-associated molecular patterns (PAMPs) modification, down-regulation of NK cell activity and complement receptors, resulting in increased secretion of inflammatory factors. Consequently, epithelial tissues lining up female reproductive tract express innate immune sensors including anti-microbial peptides responsible for forming primary barriers and have displayed an effective potent anti-HIV activity during phase I/II clinical trials.
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8
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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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9
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Maloney BE, Perera KD, Saunders DRD, Shadipeni N, Fleming SD. Interactions of viruses and the humoral innate immune response. Clin Immunol 2020; 212:108351. [PMID: 32028020 DOI: 10.1016/j.clim.2020.108351] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/01/2020] [Accepted: 02/01/2020] [Indexed: 12/13/2022]
Abstract
The innate immune response is crucial for defense against virus infections where the complement system, coagulation cascade and natural antibodies play key roles. These immune components are interconnected in an intricate network and are tightly regulated to maintain homeostasis and avoid uncontrolled immune responses. Many viruses in turn have evolved to modulate these interactions through various strategies to evade innate immune activation. This review summarizes the current understanding on viral strategies to inhibit the activation of complement and coagulation cascades, evade natural antibody-mediated clearance and utilize complement regulatory mechanisms to their advantage.
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Affiliation(s)
- Bailey E Maloney
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA
| | - Krishani Dinali Perera
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA
| | - Danielle R D Saunders
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA
| | - Naemi Shadipeni
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA
| | - Sherry D Fleming
- Division of Biology, Kansas State University, Manhattan, KS, USA.
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10
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Bertram KM, Tong O, Royle C, Turville SG, Nasr N, Cunningham AL, Harman AN. Manipulation of Mononuclear Phagocytes by HIV: Implications for Early Transmission Events. Front Immunol 2019; 10:2263. [PMID: 31616434 PMCID: PMC6768965 DOI: 10.3389/fimmu.2019.02263] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 09/09/2019] [Indexed: 12/11/2022] Open
Abstract
Mononuclear phagocytes are antigen presenting cells that play a key role in linking the innate and adaptive immune systems. In tissue, these consist of Langerhans cells, dendritic cells and macrophages, all of which express the key HIV entry receptors CD4 and CCR5 making them directly infectible with HIV. Mononuclear phagocytes are the first cells of the immune system to interact with invading pathogens such as HIV. Each cell type expresses a specific repertoire of pathogen binding receptors which triggers pathogen uptake and the release of innate immune cytokines. Langerhans cells and dendritic cells migrate to lymph nodes and present antigens to CD4 T cells, whereas macrophages remain tissue resident. Here we review how HIV-1 manipulates these cells by blocking their ability to produce innate immune cytokines and taking advantage of their antigen presenting cell function in order to gain transport to its primary target cells, CD4 T cells.
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Affiliation(s)
- Kirstie Melissa Bertram
- School of Medical Sciences, University of Sydney, Sydney, NSW, Australia.,Center for Virus Research, The Westmead Institute for Medical Research, Sydney, NSW, Australia
| | - Orion Tong
- School of Medical Sciences, University of Sydney, Sydney, NSW, Australia.,Center for Virus Research, The Westmead Institute for Medical Research, Sydney, NSW, Australia
| | - Caroline Royle
- School of Medical Sciences, University of Sydney, Sydney, NSW, Australia.,Center for Virus Research, The Westmead Institute for Medical Research, Sydney, NSW, Australia
| | - Stuart Grant Turville
- HIV Biology, Kirby Institute, Kensington, NSW, Australia.,The University of New South Whales, Sydney, NSW, Australia
| | - Najla Nasr
- School of Medical Sciences, University of Sydney, Sydney, NSW, Australia.,Center for Virus Research, The Westmead Institute for Medical Research, Sydney, NSW, Australia
| | - Anthony Lawrence Cunningham
- School of Medical Sciences, University of Sydney, Sydney, NSW, Australia.,Center for Virus Research, The Westmead Institute for Medical Research, Sydney, NSW, Australia
| | - Andrew Nicholas Harman
- School of Medical Sciences, University of Sydney, Sydney, NSW, Australia.,Center for Virus Research, The Westmead Institute for Medical Research, Sydney, NSW, Australia
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11
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Pipperger L, Koske I, Wild N, Müllauer B, Krenn D, Stoiber H, Wollmann G, Kimpel J, von Laer D, Bánki Z. Xenoantigen-Dependent Complement-Mediated Neutralization of Lymphocytic Choriomeningitis Virus Glycoprotein-Pseudotyped Vesicular Stomatitis Virus in Human Serum. J Virol 2019; 93:e00567-19. [PMID: 31243134 PMCID: PMC6714799 DOI: 10.1128/jvi.00567-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 06/18/2019] [Indexed: 01/09/2023] Open
Abstract
Neutralization by antibodies and complement limits the effective dose and thus the therapeutic efficacy of oncolytic viruses after systemic application. We and others previously showed that pseudotyping of oncolytic rhabdoviruses such as maraba virus and vesicular stomatitis virus (VSV) with the lymphocytic choriomeningitis virus glycoprotein (LCMV-GP) results in only a weak induction of neutralizing antibodies. Moreover, LCMV-GP-pseudotyped VSV (VSV-GP) was significantly more stable in normal human serum (NHS) than VSV. Here, we demonstrate that depending on the cell line used for virus production, VSV-GP showed different complement sensitivities in nonimmune NHS. The NHS-mediated titer reduction of VSV-GP was dependent on activation of the classical complement pathway, mainly by natural IgM antibodies against xenoantigens such as galactose-α-(1,3)-galactose (α-Gal) or N-glycolylneuraminic acid (Neu5Gc) expressed on nonhuman production cell lines. VSV-GP produced on human cell lines was stable in NHS. However, VSV-GP generated in transduced human cells expressing α-Gal became sensitive to NHS. Furthermore, GP-specific antibodies induced complement-mediated neutralization of VSV-GP independently of the producer cell line, suggesting that complement regulatory proteins potentially acquired by the virus during the budding process are not sufficient to rescue the virus from antibody-dependent complement-mediated lysis. Thus, our study points to the importance of a careful selection of cell lines for viral vector production for clinical use.IMPORTANCE Systemic application aims to deliver oncolytic viruses to tumors as well as to metastatic lesions. However, we found that xenoantigens incorporated onto the viral surface from nonhuman production cell lines are recognized by natural antibodies in human serum and that the virus is thereby inactivated by complement lysis. Hence, to maximize the effective dose, careful selection of cell lines for virus production is crucial.
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Affiliation(s)
- Lisa Pipperger
- Division of Virology, Medical University of Innsbruck, Innsbruck, Austria
| | - Iris Koske
- Division of Virology, Medical University of Innsbruck, Innsbruck, Austria
| | - Nicole Wild
- Division of Virology, Medical University of Innsbruck, Innsbruck, Austria
| | - Brigitte Müllauer
- Division of Virology, Medical University of Innsbruck, Innsbruck, Austria
| | - Daniela Krenn
- Division of Virology, Medical University of Innsbruck, Innsbruck, Austria
| | - Heribert Stoiber
- Division of Virology, Medical University of Innsbruck, Innsbruck, Austria
| | - Guido Wollmann
- Division of Virology, Medical University of Innsbruck, Innsbruck, Austria
- Christian Doppler Laboratory for Viral Immunotherapy of Cancer, Medical University of Innsbruck, Innsbruck, Austria
| | - Janine Kimpel
- Division of Virology, Medical University of Innsbruck, Innsbruck, Austria
| | - Dorothee von Laer
- Division of Virology, Medical University of Innsbruck, Innsbruck, Austria
| | - Zoltán Bánki
- Division of Virology, Medical University of Innsbruck, Innsbruck, Austria
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12
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Dittmer U, Sutter K, Kassiotis G, Zelinskyy G, Bánki Z, Stoiber H, Santiago ML, Hasenkrug KJ. Friend retrovirus studies reveal complex interactions between intrinsic, innate and adaptive immunity. FEMS Microbiol Rev 2019; 43:435-456. [PMID: 31087035 PMCID: PMC6735856 DOI: 10.1093/femsre/fuz012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 05/13/2019] [Indexed: 12/14/2022] Open
Abstract
Approximately 4.4% of the human genome is comprised of endogenous retroviral sequences, a record of an evolutionary battle between man and retroviruses. Much of what we know about viral immunity comes from studies using mouse models. Experiments using the Friend virus (FV) model have been particularly informative in defining highly complex anti-retroviral mechanisms of the intrinsic, innate and adaptive arms of immunity. FV studies have unraveled fundamental principles about how the immune system controls both acute and chronic viral infections. They led to a more complete understanding of retroviral immunity that begins with cellular sensing, production of type I interferons, and the induction of intrinsic restriction factors. Novel mechanisms have been revealed, which demonstrate that these earliest responses affect not only virus replication, but also subsequent innate and adaptive immunity. This review on FV immunity not only surveys the complex host responses to a retroviral infection from acute infection to chronicity, but also highlights the many feedback mechanisms that regulate and counter-regulate the various arms of the immune system. In addition, the discovery of molecular mechanisms of immunity in this model have led to therapeutic interventions with implications for HIV cure and vaccine development.
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Affiliation(s)
- Ulf Dittmer
- Institute for Virology, University Clinics Essen, University of Duisburg-Essen, Virchowstr. 179, 45147 Essen, Germany
| | - Kathrin Sutter
- Institute for Virology, University Clinics Essen, University of Duisburg-Essen, Virchowstr. 179, 45147 Essen, Germany
| | - George Kassiotis
- Retroviral Immunology, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Department of Medicine, Faculty of Medicine, Imperial College London, St Mary's Hospital, Praed St, Paddington, London W2 1NY, UK
| | - Gennadiy Zelinskyy
- Institute for Virology, University Clinics Essen, University of Duisburg-Essen, Virchowstr. 179, 45147 Essen, Germany
| | - Zoltán Bánki
- Division of Virology, Medical University of Innsbruck, Peter-Mayrstr. 4b, A-6020 Innsbruck, Austria
| | - Heribert Stoiber
- Division of Virology, Medical University of Innsbruck, Peter-Mayrstr. 4b, A-6020 Innsbruck, Austria
| | - Mario L Santiago
- University of Colorado School of Medicine, 12700E 19th Ave, Aurora, CO 80045, USA
| | - Kim J Hasenkrug
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, NIH, 903S 4th Street, Hamilton, MT 59840, USA
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13
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Analysis of Complement-Mediated Lysis of Simian Immunodeficiency Virus (SIV) and SIV-Infected Cells Reveals Sex Differences in Vaccine-Induced Immune Responses in Rhesus Macaques. J Virol 2018; 92:JVI.00721-18. [PMID: 30021899 DOI: 10.1128/jvi.00721-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 07/16/2018] [Indexed: 01/06/2023] Open
Abstract
An effective human immunodeficiency virus (HIV) vaccine has yet to be developed, and defining immune correlates of protection against HIV infection is of paramount importance to inform future vaccine design. The complement system is a component of innate immunity that can directly lyse pathogens and shape adaptive immunity. To determine if complement lysis of simian immunodeficiency virus (SIV) and/or SIV-infected cells represents a protective immune correlate against SIV infection, sera from previously vaccinated and challenged rhesus macaques were analyzed for the induction of antibody-dependent complement-mediated lysis (ADCML). Importantly, the vaccine regimen, consisting of a replication-competent adenovirus type 5 host-range mutant SIV recombinant prime followed by a monomeric gp120 or oligomeric gp140 boost, resulted in overall delayed SIV acquisition only in females. Here, sera from all vaccinated animals induced ADCML of SIV and SIV-infected cells efficiently, regardless of sex. A modest correlation of SIV lysis with a reduced infection rate in males but not females, together with a reduced peak viremia in all animals boosted with gp140, suggested a potential for influencing protective efficacy. Gag-specific IgG and gp120-specific IgG and IgM correlated with SIV lysis in females, while Env-specific IgM correlated with SIV-infected cell lysis in males, indicating sex differences in vaccine-induced antibody characteristics and function. In fact, gp120/gp140-specific antibody functional correlates between antibody-dependent cellular cytotoxicity, antibody-dependent phagocytosis, and ADCML as well as the gp120-specific IgG glycan profiles and the corresponding ADCML correlations varied depending on the sex of the vaccinees. Overall, these data suggest that sex influences vaccine-induced antibody function, which should be considered in the design of globally effective HIV vaccines in the future.IMPORTANCE An HIV vaccine would thwart the spread of HIV infection and save millions of lives. Unfortunately, the immune responses conferring universal protection from HIV infection are poorly defined. The innate immune system, including the complement system, is an evolutionarily conserved, basic means of protection from infection. Complement can prevent infection by directly lysing incoming pathogens. We found that vaccination against SIV in rhesus macaques induces antibodies that are capable of directing complement lysis of SIV and SIV-infected cells in both sexes. We also found sex differences in vaccine-induced antibody species and their functions. Overall, our data suggest that sex affects vaccine-induced antibody characteristics and function and that males and females might require different immune responses to protect against HIV infection. This information could be used to generate highly effective HIV vaccines for both sexes in the future.
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Relative Contribution of Cellular Complement Inhibitors CD59, CD46, and CD55 to Parainfluenza Virus 5 Inhibition of Complement-Mediated Neutralization. Viruses 2018; 10:v10050219. [PMID: 29693588 PMCID: PMC5977212 DOI: 10.3390/v10050219] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 04/20/2018] [Accepted: 04/22/2018] [Indexed: 12/22/2022] Open
Abstract
The complement system is a part of the innate immune system that viruses need to face during infections. Many viruses incorporate cellular regulators of complement activation (RCA) to block complement pathways and our prior work has shown that Parainfluenza virus 5 (PIV5) incorporates CD55 and CD46 to delay complement-mediated neutralization. In this paper, we tested the role of a third individual RCA inhibitor CD59 in PIV5 interactions with complement pathways. Using a cell line engineered to express CD59, we show that small levels of functional CD59 are associated with progeny PIV5, which is capable of blocking assembly of the C5b-C9 membrane attack complex (MAC). PIV5 containing CD59 (PIV5-CD59) showed increased resistance to complement-mediated neutralization in vitro comparing to PIV5 lacking regulators. Infection of A549 cells with PIV5 and RSV upregulated CD59 expression. TGF-beta treatment of PIV5-infected cells also increased cell surface CD59 expression and progeny virions were more resistant to complement-mediated neutralization. A comparison of individual viruses containing only CD55, CD46, or CD59 showed a potency of inhibiting complement-mediated neutralization, which followed a pattern of CD55 > CD46 > CD59.
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15
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Somiya M, Liu Q, Kuroda S. Current Progress of Virus-mimicking Nanocarriers for Drug Delivery. Nanotheranostics 2017; 1:415-429. [PMID: 29188175 PMCID: PMC5704007 DOI: 10.7150/ntno.21723] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Accepted: 10/09/2017] [Indexed: 12/14/2022] Open
Abstract
Nanomedicines often involve the use of nanocarriers as a delivery system for drugs or genes for maximizing the therapeutic effect and/or minimizing the adverse effect. From drug administration to therapeutic activity, nanocarriers must evade the host's immune system, specifically and efficiently target and enter the cell, and release their payload into the cell cytoplasm by endosomal escape. These processes constitute the early infection stage of viruses. Viruses are a powerful natural nanomaterial for the efficient delivery of genetic information by sophisticated mechanisms. Over the past two decades, many virus-inspired nanocarriers have been generated to permit successful drug and gene delivery. In this review, we summarize the early infection machineries of viruses, of which the part has so far been utilized for delivery systems. Furthermore, we describe basics and applications of the bio-nanocapsule, which is a hepatitis B virus-mimicking nanoparticle harboring nearly all activities involved in the early infection machineries (i.e., stealth activity, targeting activity, cell entry activity, endosomal escaping activity).
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Affiliation(s)
| | | | - Shun'ichi Kuroda
- The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan
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16
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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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17
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Agrawal P, Nawadkar R, Ojha H, Kumar J, Sahu A. Complement Evasion Strategies of Viruses: An Overview. Front Microbiol 2017; 8:1117. [PMID: 28670306 PMCID: PMC5472698 DOI: 10.3389/fmicb.2017.01117] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 05/31/2017] [Indexed: 12/11/2022] Open
Abstract
Being a major first line of immune defense, the complement system keeps a constant vigil against viruses. Its ability to recognize large panoply of viruses and virus-infected cells, and trigger the effector pathways, results in neutralization of viruses and killing of the infected cells. This selection pressure exerted by complement on viruses has made them evolve a multitude of countermeasures. These include targeting the recognition molecules for the avoidance of detection, targeting key enzymes and complexes of the complement pathways like C3 convertases and C5b-9 formation - either by encoding complement regulators or by recruiting membrane-bound and soluble host complement regulators, cleaving complement proteins by encoding protease, and inhibiting the synthesis of complement proteins. Additionally, viruses also exploit the complement system for their own benefit. For example, they use complement receptors as well as membrane regulators for cellular entry as well as their spread. Here, we provide an overview on the complement subversion mechanisms adopted by the members of various viral families including Poxviridae, Herpesviridae, Adenoviridae, Flaviviridae, Retroviridae, Picornaviridae, Astroviridae, Togaviridae, Orthomyxoviridae and Paramyxoviridae.
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Affiliation(s)
- Palak Agrawal
- Complement Biology Laboratory, National Centre for Cell Science, Savitribai Phule Pune UniversityPune, India
| | - Renuka Nawadkar
- Complement Biology Laboratory, National Centre for Cell Science, Savitribai Phule Pune UniversityPune, India
| | - Hina Ojha
- Complement Biology Laboratory, National Centre for Cell Science, Savitribai Phule Pune UniversityPune, India
| | - Jitendra Kumar
- Complement Biology Laboratory, National Centre for Cell Science, Savitribai Phule Pune UniversityPune, India
| | - Arvind Sahu
- Complement Biology Laboratory, National Centre for Cell Science, Savitribai Phule Pune UniversityPune, India
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18
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Leong YA, Atnerkar A, Yu D. Human Immunodeficiency Virus Playing Hide-and-Seek: Understanding the T FH Cell Reservoir and Proposing Strategies to Overcome the Follicle Sanctuary. Front Immunol 2017; 8:622. [PMID: 28620380 PMCID: PMC5449969 DOI: 10.3389/fimmu.2017.00622] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 05/10/2017] [Indexed: 12/20/2022] Open
Abstract
Human immunodeficiency virus (HIV) infects millions of people worldwide, and new cases continue to emerge. Once infected, the virus cannot be cleared by the immune system and causes acquired immunodeficiency syndrome. Combination antiretroviral therapeutic regimen effectively suppresses viral replication and halts disease progression. The treatment, however, does not eliminate the virus-infected cells, and interruption of treatment inevitably leads to viral rebound. The rebound virus originates from a group of virus-infected cells referred to as the cellular reservoir of HIV. Identifying and eliminating the HIV reservoir will prevent viral rebound and cure HIV infection. In this review, we focus on a recently discovered HIV reservoir in a subset of CD4+ T cells called the follicular helper T (TFH) cells. We describe the potential mechanisms for the emergence of reservoir in TFH cells, and the strategies to target and eliminate this viral reservoir.
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Affiliation(s)
- Yew Ann Leong
- Infection and Immunity Program, Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Anurag Atnerkar
- Infection and Immunity Program, Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Di Yu
- Infection and Immunity Program, Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Department of Immunology and Infectious Disease, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
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19
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Imran M, Manzoor S, Saalim M, Resham S, Ashraf J, Javed A, Waqar AB. HIV-1 and hijacking of the host immune system: the current scenario. APMIS 2016; 124:817-31. [PMID: 27539675 DOI: 10.1111/apm.12579] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 06/04/2016] [Indexed: 12/25/2022]
Abstract
Human immunodeficiency virus (HIV) infection is a major health burden across the world which leads to the development of acquired immune deficiency syndrome (AIDS). This review article discusses the prevalence of HIV, its major routes of transmission, natural immunity, and evasion from the host immune system. HIV is mostly prevalent in Sub-Saharan Africa and low income countries. It is mostly transmitted by sharing syringe needles, blood transfusion, and sexual routes. The host immune system is categorized into three main types; the innate, the adaptive, and the intrinsic immune system. Regarding the innate immune system against HIV, the key players are mucosal membrane, dendritic cells (DCs), complement system, interferon, and host Micro RNAs. The major components of the adaptive immune system exploited by HIV are T cells mainly CD4+ T cells and B cells. The intrinsic immune system confronted by HIV involves (apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G) APOBEC3G, tripartite motif 5-α (TRIM5a), terherin, and (SAM-domain HD-domain containing protein) SAMHD1. HIV-1 efficiently interacts with the host immune system, exploits the host machinery, successfully replicates and transmits from one cell to another. Further research is required to explore evasion strategies of HIV to develop novel therapeutic approaches against HIV.
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Affiliation(s)
- Muhammad Imran
- Atta-ur-Rahman School of Applied Bio-Sciences, Department of Healthcare Biotechnology, National University of Sciences and Technology (NUST), Islamabad, Pakistan.,Department of Medical Laboratory Sciences, Faculty of Health and Allied Sciences, Imperial College of Business Studies (ICBS), Lahore, Pakistan
| | - Sobia Manzoor
- Atta-ur-Rahman School of Applied Bio-Sciences, Department of Healthcare Biotechnology, National University of Sciences and Technology (NUST), Islamabad, Pakistan. ,
| | - Muhammad Saalim
- Atta-ur-Rahman School of Applied Bio-Sciences, Department of Healthcare Biotechnology, National University of Sciences and Technology (NUST), Islamabad, Pakistan
| | - Saleha Resham
- Atta-ur-Rahman School of Applied Bio-Sciences, Department of Healthcare Biotechnology, National University of Sciences and Technology (NUST), Islamabad, Pakistan
| | | | - Aneela Javed
- Atta-ur-Rahman School of Applied Bio-Sciences, Department of Healthcare Biotechnology, National University of Sciences and Technology (NUST), Islamabad, Pakistan
| | - Ahmed Bilal Waqar
- Department of Medical Laboratory Sciences, Faculty of Health and Allied Sciences, Imperial College of Business Studies (ICBS), Lahore, Pakistan.,Imperial Post Graduate Medical Institute, Imperial College of Business Studies (ICBS), Lahore, Pakistan
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20
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Boesch AW, Brown EP, Ackerman ME. The role of Fc receptors in HIV prevention and therapy. Immunol Rev 2016; 268:296-310. [PMID: 26497529 DOI: 10.1111/imr.12339] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Over the past decade, a wealth of experimental evidence has accumulated supporting the importance of Fc receptor (FcR) ligation in antibody-mediated pathology and protection in many disease states. Here we present the diverse evidence base that has accumulated as to the importance of antibody effector functions in the setting of HIV prevention and therapy, including clinical correlates, genetic associations, viral evasion strategies, and a rapidly growing number of compelling animal model experiments. Collectively, this work identifies antibody interactions with FcR as important to both therapeutic and prophylactic strategies involving both passive and active immunity. These findings mirror those in other fields as investigators continue to work toward identifying the right antibodies and the right effectors to be present at the right sites at the right time.
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Affiliation(s)
- Austin W Boesch
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Eric P Brown
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Margaret E Ackerman
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA.,Molecular and Cellular Biology Program, Dartmouth College, Hanover, NH, USA.,Department of Microbiology and Immunology, Geisel School of Medicine, Lebanon, NH, USA
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21
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HIV-1 strategies to overcome the immune system by evading and invading innate immune system. HIV & AIDS REVIEW 2016. [DOI: 10.1016/j.hivar.2015.07.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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22
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Blockage of CD59 Function Restores Activities of Neutralizing and Nonneutralizing Antibodies in Triggering Antibody-Dependent Complement-Mediated Lysis of HIV-1 Virions and Provirus-Activated Latently Infected Cells. J Virol 2015; 89:9393-406. [PMID: 26136568 DOI: 10.1128/jvi.01614-15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 06/23/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Both HIV-1 virions and infected cells use their surface regulators of complement activation (RCA) to resist antibody-dependent complement-mediated lysis (ADCML). Blockage of the biological function of RCA members, particularly CD59 (a key RCA member that controls formation of the membrane attack complex at the terminal stage of the complement activation cascades via all three activation pathways), has rendered both HIV-1 virions and infected cells sensitive to ADCML mediated by anti-Env antibodies (Abs) or sera/plasma from patients at different stages of viral infection. In the current study, we used the well-characterized anti-HIV-1 neutralizing Abs (nAbs), including 2G12, 2F5, and 4E10, and non-nAbs, including 2.2C, A32, N5-i5, and N12-i15, to investigate whether the enhancement of ADCML by blockage of CD59 function is mediated by nAbs, non-nAbs, or both. We found that all nAbs and two non-nAbs (N5-i5 and A32) strongly reacted to three HIV-1 laboratory strains (R5, X4, and R5/X4), six primary isolates, and provirus-activated ACH-2 cells examined. In contrast, two non-nAbs, 2.2C and N12-i15, reacted weakly and did not react to these targets, respectively. After blockage of CD59 function, the reactive Abs, regardless of their neutralizing activities, significantly enhanced specific ADCML of HIV-1 virions (both laboratory strains and primary isolates) and provirus-activated latently infected cells. The ADMCL efficacy positively correlated with the enzyme-linked immunosorbent assay-reactive intensity of those Abs with their targets. Thus, blockage of RCA function represents a novel approach to restore activities of both nAbs and non-nAbs in triggering ADCML of HIV-1 virions and provirus-activated latently infected cells. IMPORTANCE There is a renewed interest in the potential role of non-nAbs in the control of HIV-1 infection. Our data, for the first time, demonstrated that blockage of the biological function of RCA members rendered both HIV-1 virions and infected cells sensitive to ADCML mediated by not only nAbs but also non-nAbs. Our results are significant in developing novel immune-based approaches to restore the functions of nAbs and non-nAbs in the circulation of HIV-1-infected individuals to specifically target and clear HIV-1 virions and infected cells. Our data also provide new insights into the mechanisms by which HIV-1 virions and infected cells escape Ab-mediated immunity and could aid in the design and/or development of therapeutic HIV-1 vaccines. In addition, a combination of antiretroviral therapy with RCA blockage, provirus activators, and therapeutic vaccines may represent a novel approach to eliminate HIV-1 reservoirs, i.e., the infected cells harboring replication-competent proviruses and residual viremia.
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23
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Complement-Opsonized HIV-1 Overcomes Restriction in Dendritic Cells. PLoS Pathog 2015; 11:e1005005. [PMID: 26121641 PMCID: PMC4485899 DOI: 10.1371/journal.ppat.1005005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 06/05/2015] [Indexed: 11/19/2022] Open
Abstract
DCs express intrinsic cellular defense mechanisms to specifically inhibit HIV-1 replication. Thus, DCs are productively infected only at very low levels with HIV-1, and this non-permissiveness of DCs is suggested to go along with viral evasion. We now illustrate that complement-opsonized HIV-1 (HIV-C) efficiently bypasses SAMHD1 restriction and productively infects DCs including BDCA-1 DCs. Efficient DC infection by HIV-C was also observed using single-cycle HIV-C, and correlated with a remarkable elevated SAMHD1 T592 phosphorylation but not SAMHD1 degradation. If SAMHD1 phosphorylation was blocked using a CDK2-inhibitor HIV-C-induced DC infection was also significantly abrogated. Additionally, we found a higher maturation and co-stimulatory potential, aberrant type I interferon expression and signaling as well as a stronger induction of cellular immune responses in HIV-C-treated DCs. Collectively, our data highlight a novel protective mechanism mediated by complement opsonization of HIV to effectively promote DC immune functions, which might be in the future exploited to tackle HIV infection. We here give insight into a substantial novel way of dendritic cell modulation at least during acute HIV-1 infection by triggering integrin receptor signaling. We found that complement-opsonization of the virus is able to relieve SAMHD1 restriction in DCs, thereby initiating strong maturation and co-stimulatory capacity of the cells and stimulating efficient cellular and humoral antiviral immune responses. This newly described way of DC modulation by complement might be exploited to find novel therapeutic targets promoting DC immune functions against HIV.
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24
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Herrero R, Real LM, Rivero-Juárez A, Pineda JA, Camacho Á, Macías J, Laplana M, Konieczny P, Márquez FJ, Souto JC, Soria JM, Saulle I, Lo Caputo S, Biasin M, Rivero A, Fibla J, Caruz A. Association of complement receptor 2 polymorphisms with innate resistance to HIV-1 infection. Genes Immun 2015; 16:134-41. [PMID: 25569262 DOI: 10.1038/gene.2014.71] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 11/10/2014] [Accepted: 11/12/2014] [Indexed: 11/09/2022]
Abstract
HIV-1 induces activation of complement through the classical and lectin pathways. However, the virus incorporates several membrane-bound or soluble regulators of complement activation (RCA) that inactivate complement. HIV-1 can also use the complement receptors (CRs) for complement-mediated antibody-dependent enhancement of infection (Ć-ADE). We hypothesize that hypofunctional polymorphisms in RCA or CRs may protect from HIV-1 infection. For this purpose, 139 SNPs located in 19 RCA and CRs genes were genotyped in a population of 201 Spanish HIV-1-exposed seronegative individuals (HESN) and 250 HIV-1-infected patients. Two SNPs were associated with infection susceptibility, rs1567190 in CR2 (odds ratio (OR) = 2.27, P = 1 × 10(-4)) and rs2842704 in C4BPA (OR = 2.11, P = 2 × 10(-4)). To replicate this finding, we analyzed a cohort of Italian, sexually HESN individuals. Although not significant (P = 0.25, OR = 1.57), similar genotypic proportions were obtained for the CR2 marker rs1567190. The results of the two association analyses were combined through a random effect meta-analysis, with a significant P-value of 2.6 x 10(-5) (OR = 2.07). Furthermore, we found that the protective CR2 genotype is correlated with lower levels CR2 mRNA as well as differences in the ratio of the long and short CR2 isoforms.
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Affiliation(s)
- R Herrero
- Immunogenetics Unit, Department of Experimental Biology, University of Jaen, Jaen, Spain
| | - L M Real
- Infectious Diseases and Microbiology Clinical Unit. Valme Hospital, Seville, Spain
| | - A Rivero-Juárez
- Maimonides Institute for Research in Biomedicine of Cordoba (IMIBIC)/Reina Sofia University Hospital, Cordoba, Spain
| | - J A Pineda
- Infectious Diseases and Microbiology Clinical Unit. Valme Hospital, Seville, Spain
| | - Á Camacho
- Maimonides Institute for Research in Biomedicine of Cordoba (IMIBIC)/Reina Sofia University Hospital, Cordoba, Spain
| | - J Macías
- Infectious Diseases and Microbiology Clinical Unit. Valme Hospital, Seville, Spain
| | - M Laplana
- Human Genetics Unit, Department of Basic Medical Sciences, University of Lleida IRBLleida, Lleida, Catalonia, Spain
| | - P Konieczny
- Immunogenetics Unit, Department of Experimental Biology, University of Jaen, Jaen, Spain
| | - F J Márquez
- Immunogenetics Unit, Department of Experimental Biology, University of Jaen, Jaen, Spain
| | - J C Souto
- Institut d'Investigació Biomèdica Sant Pau (IIB-Sant Pau), Hospital de la Santa Creu i de Sant Pau, Barcelone, Spain
| | - J M Soria
- Institut d'Investigació Biomèdica Sant Pau (IIB-Sant Pau), Hospital de la Santa Creu i de Sant Pau, Barcelone, Spain
| | - I Saulle
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | | | - M Biasin
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - A Rivero
- Maimonides Institute for Research in Biomedicine of Cordoba (IMIBIC)/Reina Sofia University Hospital, Cordoba, Spain
| | - J Fibla
- Human Genetics Unit, Department of Basic Medical Sciences, University of Lleida IRBLleida, Lleida, Catalonia, Spain
| | - A Caruz
- Immunogenetics Unit, Department of Experimental Biology, University of Jaen, Jaen, Spain
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25
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Complement and HIV-I infection/HIV-associated neurocognitive disorders. J Neurovirol 2014; 20:184-98. [PMID: 24639397 DOI: 10.1007/s13365-014-0243-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 02/07/2014] [Accepted: 02/11/2014] [Indexed: 10/25/2022]
Abstract
The various neurological complications associated with HIV-1 infection, specifically HIV-associated neurocognitive disorders (HAND) persist as a major public health burden worldwide. Despite the widespread use of anti-retroviral therapy, the prevalence of HAND is significantly high. HAND results from the direct effects of an HIV-1 infection as well as secondary effects of HIV-1-induced immune reaction and inflammatory response. Complement, a critical mediator of innate and acquired immunity, plays important roles in defeating many viral infections by the formation of a lytic pore or indirectly by opsonization and recruitment of phagocytes. While the role of complement in the pathogenesis of HIV-1 infection and HAND has been previously recognized for over 15 years, it has been largely underestimated thus far. Complement can be activated through HIV-1 envelope proteins, mannose-binding lectins (MBL), and anti-HIV-1 antibodies. Complement not only fights against HIV-1 infection but also enhances HIV-1 infection. In addition, HIV-1 can hijack complement regulators such as CD59 and CD55 and can utilize these regulators and factor H to escape from complement attack. Normally, complement levels in brain are much lower than plasma levels and there is no or little complement deposition in brain cells. Interestingly, local production and deposition of complement are dramatically increased in HIV-1-infected brain, indicating that complement may contribute to the pathogenesis of HAND. Here, we review the current understanding of the role of complement in HIV-1 infection and HAND, as well as potential therapeutic approaches targeting the complement system for the treatment and eradications of HIV-1 infection.
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Huber G, Bánki Z, Kunert R, Stoiber H. Novel bifunctional single-chain variable antibody fragments to enhance virolysis by complement: generation and proof-of-concept. BIOMED RESEARCH INTERNATIONAL 2014; 2014:971345. [PMID: 24524088 PMCID: PMC3913500 DOI: 10.1155/2014/971345] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 10/03/2013] [Indexed: 12/20/2022]
Abstract
When bound to the envelope of viruses, factor H (FH), a soluble regulator of complement activation, contributes to the protection against a potent immune defense mechanism, the complement-mediated lysis (CML). Thus, removing FH from the surface renders viruses, such as HIV, susceptible to CML. For a proof of concept, we developed a construct consisting of recombinant bifunctional single-chain variable fragment (scFv) based on a monoclonal antibody against Friend murine leukemia virus (F-MuLV) envelope protein gp70, which was coupled to specific binding domains (short consensus repeats 19-20; SCR1920) of FH. We used Pichia pastoris as expression system in common shake flasks and optimized expression in high density bench top fermentation. Specific binding of recombinant scFv was proven by flow cytometry. The recombinant scFv-SCR significantly enhanced CML of F-MuLV in vitro implying that FH binding to the viral surface was impaired by the scFv-SCR. This novel concept to enhance virolysis may provide a new approach for antiviral treatment.
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Affiliation(s)
- Georg Huber
- Division of Virology, Innsbruck Medical University, Peter-Mayr-Straße 4b, 6020 Innsbruck, Austria
| | - Zoltán Bánki
- Division of Virology, Innsbruck Medical University, Peter-Mayr-Straße 4b, 6020 Innsbruck, Austria
| | - Renate Kunert
- Department of Biotechnology, VIBT, BOKU-University of Natural Resources and Life Sciences, Muthgasse 11, 1190 Vienna, Austria
| | - Heribert Stoiber
- Division of Virology, Innsbruck Medical University, Peter-Mayr-Straße 4b, 6020 Innsbruck, Austria
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Innate immune evasion strategies by human immunodeficiency virus type 1. ISRN AIDS 2013; 2013:954806. [PMID: 24052891 PMCID: PMC3767209 DOI: 10.1155/2013/954806] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 07/09/2013] [Indexed: 12/21/2022]
Abstract
Host immune components play both beneficial and pathogenic roles in human immunodeficiency virus type 1 (HIV-1) infection. During the initial stage of viral infection, a complex network of innate immune factors are activated. For instance, the immune cells express a number of inflammatory proteins including cytokines, chemokines, and antiviral restriction factors. These factors, specifically, interferons (IFNs) play a crucial role in antiviral defense system by modulating the downstream signaling events, by inducing maturation of dendritic cells (DCs), and by activation of macrophages, natural killer (NK) cells, and B and T cells. However, HIV-1 has evolved to utilize a number of strategies to overcome the antiviral effects of the host innate immune system. This review discusses the pathways and strategies utilized by HIV-1 to establish latent and persistent infection by defeating host's innate defense system.
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Effect of complement on HIV-2 plasma antiviral activity is intratype specific and potent. J Virol 2012; 87:273-81. [PMID: 23077299 DOI: 10.1128/jvi.01640-12] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus type 2 (HIV-2)-infected individuals develop immunodeficiency with a considerable delay and transmit the virus at rates lower than HIV-1-infected persons. Conceivably, comparative studies on the immune responsiveness of HIV-1- and HIV-2-infected hosts may help to explain the differences in pathogenesis and transmission between the two types of infection. Previous studies have shown that the neutralizing antibody response is more potent and broader in HIV-2 than in HIV-1 infection. In the present study, we have examined further the function of the humoral immune response and studied the effect of complement on the antiviral activity of plasma from singly HIV-1- or HIV-2-infected individuals, as well as HIV-1/HIV-2 dually infected individuals. The neutralization and antibody-dependent complement-mediated inactivation of HIV-1 and HIV-2 isolates were tested in a plaque reduction assay using U87.CD4.CCR5 cells. The results showed that the addition of complement increased intratype antiviral activities of both HIV-1 and HIV-2 plasma samples, although the complement effect was more pronounced with HIV-2 than HIV-1 plasma. Using an area-under-the-curve (AUC)-based readout, multivariate statistical analysis confirmed that the type of HIV infection was independently associated with the magnitude of the complement effect. The analyses carried out with purified IgG indicated that the complement effect was largely exerted through the classical complement pathway involving IgG in both HIV-1 and HIV-2 infections. In summary, these findings suggest that antibody binding to HIV-2 structures facilitates the efficient use of complement and thereby may be one factor contributing to a strong antiviral activity present in HIV-2 infection.
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Ejaz A, Steinmann E, Bánki Z, Anggakusuma, Khalid S, Lengauer S, Wilhelm C, Zoller H, Schloegl A, Steinmann J, Grabski E, Kleines M, Pietschmann T, Stoiber H. Specific acquisition of functional CD59 but not CD46 or CD55 by hepatitis C virus. PLoS One 2012; 7:e45770. [PMID: 23049856 PMCID: PMC3458075 DOI: 10.1371/journal.pone.0045770] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 08/22/2012] [Indexed: 01/07/2023] Open
Abstract
Viruses of different families encode for regulators of the complement system (RCAs) or acquire such RCAs from the host to get protection against complement-mediated lysis (CML). As hepatitis C virus (HCV) shares no genetic similarity to any known RCA and is detectable at high titers in sera of infected individuals, we investigated whether HCV has adapted host-derived RCAs to resist CML. Here we report that HCV selectively incorporates CD59 while neither CD55, nor CD46 are associated with the virus. The presence of CD59 was shown by capture assays using patient- and cell culture-derived HCV isolates. Association of CD59 with HCV was further confirmed by Western blot analysis using purified viral supernatants from infected Huh 7.5 cells. HCV captured by antibodies specific for CD59 remained infectious for Huh 7.5 cells. In addition, blocking of CD59 in the presence of active complement reduced the titer of HCV most likely due to CML. HCV produced in CD59 knock-down cells were more significantly susceptible to CML compared to wild type virus, but neither replication, assembly nor infectivity of the virus seemed to be impaired in the absence of CD59. In summary our data indicate that HCV incorporates selectively CD59 in its envelope to gain resistance to CML in serum of infected individuals.
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Affiliation(s)
- Asim Ejaz
- Institute of Virology, Innsbruck Medical University, Innsbruck, Austria
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Virion-associated complement regulator CD55 is more potent than CD46 in mediating resistance of mumps virus and vesicular stomatitis virus to neutralization. J Virol 2012; 86:9929-40. [PMID: 22761385 DOI: 10.1128/jvi.01154-12] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enveloped viruses can incorporate host cell membrane proteins during the budding process. Here we demonstrate that mumps virus (MuV) and vesicular stomatitis virus (VSV) assemble to include CD46 and CD55, two host cell regulators which inhibit propagation of complement pathways through distinct mechanisms. Using viruses which incorporated CD46 alone, CD55 alone, or both CD46 and CD55, we have tested the relative contribution of these regulators in resistance to complement-mediated neutralization. Virion-associated CD46 and CD55 were biologically active, with VSV showing higher levels of activity of both cofactors, which promoted factor I-mediated cleavage of C3b into iC3b as well as decay-accelerating factor (DAF) activity against the C3 convertase, than MuV. Time courses of in vitro neutralization with normal human serum (NHS) showed that both regulators could delay neutralization, but viruses containing CD46 alone were neutralized faster and more completely than viruses containing CD55 alone. A dominant inhibitory role for CD55 was most evident for VSV, where virus containing CD55 alone was not substantially different in neutralization kinetics from virus harboring both regulators. Electron microscopy showed that VSV neutralization proceeded through virion aggregation followed by lysis, with virion-associated CD55 providing a delay in both aggregation and lysis more substantial than that conferred by CD46. Our results demonstrate the functional significance of incorporation of host cell factors during virion envelope assembly. They also define pathways of virus complement-mediated neutralization and suggest the design of more effective viral vectors.
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The rickettsial OmpB β-peptide of Rickettsia conorii is sufficient to facilitate factor H-mediated serum resistance. Infect Immun 2012; 80:2735-43. [PMID: 22615250 DOI: 10.1128/iai.00349-12] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Pathogenic species of the spotted fever group Rickettsia are subjected to repeated exposures to the host complement system through cyclic infections of mammalian and tick hosts. The serum complement machinery is a formidable obstacle for bacteria to overcome if they endeavor to endure this endozoonotic cycle. We have previously demonstrated that that the etiologic agent of Mediterranean spotted fever, Rickettsia conorii, is susceptible to complement-mediated killing only in the presence of specific monoclonal antibodies. We have also shown that in the absence of particular neutralizing antibody, R. conorii is resistant to the effects of serum complement. We therefore hypothesized that the interactions between fluid-phase complement regulators and conserved rickettsial outer membrane-associated proteins are critical to mediate serum resistance. We demonstrate here that R. conorii specifically interacts with the soluble host complement inhibitor, factor H. Depletion of factor H from normal human serum renders R. conorii more susceptible to C3 and membrane attack complex deposition and to complement-mediated killing. We identified the autotransporter protein rickettsial OmpB (rOmpB) as a factor H ligand and further demonstrate that the rOmpB β-peptide is sufficient to mediate resistance to the bactericidal properties of human serum. Taken together, these data reveal an additional function for the highly conserved rickettsial surface cell antigen, rOmpB, and suggest that the ability to evade complement-mediated clearance from the hematogenous circulation is a novel virulence attribute for this class of pathogens.
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Pyaram K, Yadav VN, Reza MJ, Sahu A. Virus–complement interactions: an assiduous struggle for dominance. Future Virol 2010. [DOI: 10.2217/fvl.10.60] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The complement system is a major component of the innate immune system that recognizes invading pathogens and eliminates them by means of an array of effector mechanisms, in addition to using direct lytic destruction. Viruses, in spite of their small size and simple composition, are also deftly recognized and neutralized by the complement system. In turn, as a result of years of coevolution with the host, viruses have developed multiple mechanisms to evade the host complement. These complex interactions between the complement system and viruses have been an area of focus for over three decades. In this article, we provide a broad overview of the field using key examples and up-to-date information on the complement-evasion strategies of viruses.
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Affiliation(s)
- Kalyani Pyaram
- National Centre for Cell Science, Pune University Campus, Ganeshkhind, Pune 411007, India
| | - Viveka Nand Yadav
- National Centre for Cell Science, Pune University Campus, Ganeshkhind, Pune 411007, India
| | - Malik Johid Reza
- National Centre for Cell Science, Pune University Campus, Ganeshkhind, Pune 411007, India
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Jia L, Xu Y, Zhang C, Wang Y, Chong H, Qiu S, Wang L, Zhong Y, Liu W, Sun Y, Qiao F, Tomlinson S, Song H, Zhou Y, He Y. A novel trifunctional IgG-like bispecific antibody to inhibit HIV-1 infection and enhance lysis of HIV by targeting activation of complement. Virol J 2010; 7:142. [PMID: 20584336 PMCID: PMC2904741 DOI: 10.1186/1743-422x-7-142] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Accepted: 06/29/2010] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The complement system is not only a key component of innate immunity but also provides a first line of defense against invading pathogens, especially for viral pathogens. Human immunodeficiency virus (HIV), however, possesses several mechanisms to evade complement-mediated lysis (CoML) and exploit the complement system to enhance viral infectivity. Responsible for this intrinsic resistance against complement-mediated virolysis are complement regulatory membrane proteins derived from the host cell that inherently downregulates complement activation at several stages of the cascade. In addition, HIV is protected from complement-mediated lysis by binding soluble factor H (fH) through the viral envelope proteins, gp120 and gp41. Whereas inhibition of complement activity is the desired outcome in the vast majority of therapeutic approaches, there is a broader potential for complement-mediated inhibition of HIV by complement local stimulation. PRESENTATION OF THE HYPOTHESIS Our previous studies have proven that the complement-mediated antibody-dependent enhancement of HIV infection is mediated by the association of complement receptor type 2 bound to the C3 fragment and deposited on the surface of HIV virions. Thus, we hypothesize that another new activator of complement, consisting of two dsFv (against gp120 and against C3d respectively) linked to a complement-activating human IgG1 Fc domain ((anti-gp120 x anti-C3d)-Fc), can not only target and amplify complement activation on HIV virions for enhancing the efficiency of HIV lysis, but also reduce the infectivity of HIV through blocking the gp120 and C3d on the surface of HIV. TESTING THE HYPOTHESIS Our hypothesis was tested using cell-free HIV-1 virions cultivated in vitro and assessment of virus opsonization was performed by incubating appropriate dilutions of virus with medium containing normal human serum and purified (anti-gp120 x anti-C3d)-Fc proteins. As a control group, viruses were incubated with normal human serum under the same conditions. Virus neutralization assays were used to estimate the degree of (anti-gp120 x anti-C3d)-Fc lysis of HIV compared to untreated virus. IMPLICATIONS OF THE HYPOTHESIS The targeted complement activator, (anti-gp120 x anti-C3d)-Fc, can be used as a novel approach to HIV therapy by abrogating the complement-enhanced HIV infection of cells.
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Affiliation(s)
- Leili Jia
- Institute of Disease Control and Prevention, Academy of Military Medical Science, Beijing 100071, PR China
| | - Yuanyong Xu
- Institute of Disease Control and Prevention, Academy of Military Medical Science, Beijing 100071, PR China
| | - Chuanfu Zhang
- Institute of Disease Control and Prevention, Academy of Military Medical Science, Beijing 100071, PR China
| | - Yong Wang
- Institute of Disease Control and Prevention, Academy of Military Medical Science, Beijing 100071, PR China
| | - Huihui Chong
- Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, PR China
| | - Shaofu Qiu
- Institute of Disease Control and Prevention, Academy of Military Medical Science, Beijing 100071, PR China
| | - Ligui Wang
- Institute of Disease Control and Prevention, Academy of Military Medical Science, Beijing 100071, PR China
| | - Yanwei Zhong
- The 302nd Hospital of People's Liberation Army, Beijing 100039, PR China
| | - Weijing Liu
- Institute of Disease Control and Prevention, Academy of Military Medical Science, Beijing 100071, PR China
| | - Yansong Sun
- Institute of Disease Control and Prevention, Academy of Military Medical Science, Beijing 100071, PR China
| | - Fei Qiao
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
| | - Stephen Tomlinson
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
| | - Hongbin Song
- Institute of Disease Control and Prevention, Academy of Military Medical Science, Beijing 100071, PR China
| | - Yusen Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Yuxian He
- Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, PR China
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Jenabian MA, Saïdi H, Charpentier C, Bouhlal H, Schols D, Balzarini J, Bell TW, Vanham G, Bélec L. Differential activity of candidate microbicides against early steps of HIV-1 infection upon complement virus opsonization. AIDS Res Ther 2010; 7:16. [PMID: 20546571 PMCID: PMC2895573 DOI: 10.1186/1742-6405-7-16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 06/14/2010] [Indexed: 11/29/2022] Open
Abstract
Background HIV-1 in genital secretions may be opsonized by several molecules including complement components. Opsonized HIV-1 by complement enhances the infection of various mucosal target cells, such as dendritic cells (DC) and epithelial cells. Results We herein evaluated the effect of HIV-1 complement opsonization on microbicide candidates' activity, by using three in vitro mucosal models: CCR5-tropic HIV-1JR-CSF transcytosis through epithelial cells, HIV-1JR-CSF attachment on immature monocyte-derived dendritic cells (iMDDC), and infectivity of iMDDC by CCR5-tropic HIV-1BaL and CXCR4-tropic HIV-1NDK. A panel of 10 microbicide candidates [T20, CADA, lectines HHA & GNA, PVAS, human lactoferrin, and monoclonal antibodies IgG1B12, 12G5, 2G12 and 2F5], were investigated using cell-free unopsonized or opsonized HIV-1 by complements. Only HHA and PVAS were able to inhibit HIV trancytosis. Upon opsonization, transcytosis was affected only by HHA, HIV-1 adsorption on iMDDC by four molecules (lactoferrin, IgG1B12, IgG2G5, IgG2G12), and replication in iMDDC of HIV-1BaL by five molecules (lactoferrin, CADA, T20, IgG1B12, IgG2F5) and of HIV-1NDK by two molecules (lactoferrin, IgG12G5). Conclusion These observations demonstrate that HIV-1 opsonization by complements may modulate in vitro the efficiency of candidate microbicides to inhibit HIV-1 infection of mucosal target cells, as well as its crossing through mucosa.
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Radhakrishnan A, Yeo D, Brown G, Myaing MZ, Iyer LR, Fleck R, Tan BH, Aitken J, Sanmun D, Tang K, Yarwood A, Brink J, Sugrue RJ. Protein analysis of purified respiratory syncytial virus particles reveals an important role for heat shock protein 90 in virus particle assembly. Mol Cell Proteomics 2010; 9:1829-48. [PMID: 20530633 DOI: 10.1074/mcp.m110.001651] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
In this study, we used imaging and proteomics to identify the presence of virus-associated cellular proteins that may play a role in respiratory syncytial virus (RSV) maturation. Fluorescence microscopy of virus-infected cells revealed the presence of virus-induced cytoplasmic inclusion bodies and mature virus particles, the latter appearing as virus filaments. In situ electron tomography suggested that the virus filaments were complex structures that were able to package multiple copies of the virus genome. The virus particles were purified, and the protein content was analyzed by one-dimensional nano-LC MS/MS. In addition to all the major virus structural proteins, 25 cellular proteins were also detected, including proteins associated with the cortical actin network, energy pathways, and heat shock proteins (HSP70, HSC70, and HSP90). Representative actin-associated proteins, HSC70, and HSP90 were selected for further biological validation. The presence of beta-actin, filamin-1, cofilin-1, HSC70, and HSP90 in the virus preparation was confirmed by immunoblotting using relevant antibodies. Immunofluorescence microscopy of infected cells stained with antibodies against relevant virus and cellular proteins confirmed the presence of these cellular proteins in the virus filaments and inclusion bodies. The relevance of HSP90 to virus infection was examined using the specific inhibitors 17-N-Allylamino-17-demethoxygeldanamycin. Although virus protein expression was largely unaffected by these drugs, we noted that the formation of virus particles was inhibited, and virus transmission was impaired, suggesting an important role for HSP90 in virus maturation. This study highlights the utility of proteomics in facilitating both our understanding of the role that cellular proteins play during RSV maturation and, by extrapolation, the identification of new potential targets for antiviral therapy.
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Affiliation(s)
- Anuradha Radhakrishnan
- Division of Molecular and Cell Biology, School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
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Impaired immunogenicity of a meningococcal factor H-binding protein vaccine engineered to eliminate factor h binding. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2010; 17:1074-8. [PMID: 20519444 DOI: 10.1128/cvi.00103-10] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Meningococcal factor H-binding protein (fHbp) is a promising antigen that is part of two vaccines in clinical development. The protein specifically binds human complement factor H (fH), which downregulates complement activation on the bacterial surface and enables the organism to evade host defenses. In humans, the vaccine antigen forms a complex with fH, which may affect anti-fHbp antibody repertoire and decrease serum bactericidal activity by covering important fHbp epitopes. In a recent study, fHbp residues in contact with fH were identified from a crystal structure. Two fHbp glutamate residues that mediated ion-pair interactions with fH were replaced with alanine, and the resulting E218A/E239A mutant no longer bound the fH fragment. In the present study, we generated the E218A/E239A mutant recombinant protein and confirmed the lack of fH binding. By enzyme-linked immunosorbent assay (ELISA), the mutant fHbp showed similar respective concentration-dependent inhibition of binding of four bactericidal anti-fHbp monoclonal antibodies (MAbs) to fHbp, compared with inhibition by the soluble wild-type protein. In two mouse strains, the mutant fHbp elicited up to 4-fold-lower IgG anti-fHbp antibody titers and up to 20-fold-lower serum bactericidal titers than those elicited by the wild-type fHbp vaccine. Thus, although introduction of the two alanine substitutions to eliminate fH binding did not appear to destabilize the molecule globally, the mutations resulted in decreased immunogenicity in mouse models in which neither the mutant nor the wild-type control vaccine bound fH. These results cast doubt on the vaccine potential in humans of this mutant fHbp.
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Abstract
The complement system, a key component of innate immunity, is a first-line defender against foreign pathogens such as HIV-1. The role of the complement system in HIV-1 pathogenesis appears to be multifaceted. Although the complement system plays critical roles in clearing and neutralizing HIV-1 virions, it also represents a critical factor for the spread and maintenance of the virus in the infected host. In addition, complement regulators such as human CD59 present in the envelope of HIV-1 prevent complement-mediated lysis of HIV-1. Some novel approaches are proposed to combat HIV-1 infection through the enhancement of antibody-dependent complement activity against HIV-1. In this paper, we will review these diverse roles of complement in HIV-1 infection.
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Abstract
PURPOSE OF REVIEW Because complement is present in all fluids of the body, including serum, saliva and seminal fluid, and is found at mucosal surfaces and in the brain, all pathogens have to deal with complement proteins. Thus, immediately upon entering the host, independent on the route of infection, HIV activates the complement system. Although a first line of immune defense, complement cannot eliminate retroviral infections completely. RECENT FINDINGS Recent data indicate that complement, in concert with non-neutralizing antibodies, contributes to the control of HIV replication at early stages of infection. In parallel or at later stages, complement and non-neutralizing antibodies may counteract the immune response by enhancing HIV infection via complement and Fc-receptor-positive cells in 'cis' and 'trans'. SUMMARY This review highlights current knowledge in this field and emphasizes the contribution of complement and non-neutralizing antibodies in controlling versus and enhancing infection.
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Acquisition of complement resistance through incorporation of CD55/decay-accelerating factor into viral particles bearing baculovirus GP64. J Virol 2010; 84:3210-9. [PMID: 20071581 DOI: 10.1128/jvi.02519-09] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
A major obstacle to gene transduction by viral vectors is inactivation by human complement in vivo. One way to overcome this is to incorporate complement regulatory proteins, such as CD55/decay accelerating factor (DAF), into viral particles. Lentivirus vectors pseudotyped with the baculovirus envelope protein GP64 have been shown to acquire more potent resistance to serum inactivation and longer transgene expression than those pseudotyped with the vesicular stomatitis virus (VSV) envelope protein G. However, the molecular mechanisms underlying resistance to serum inactivation in pseudotype particles bearing the GP64 have not been precisely elucidated. In this study, we generated pseudotype and recombinant VSVs bearing the GP64. Recombinant VSVs generated in human cell lines exhibited the incorporation of human DAF in viral particles and were resistant to serum inactivation, whereas those generated in insect cells exhibited no incorporation of human DAF and were sensitive to complement inactivation. The GP64 and human DAF were detected on the detergent-resistant membrane and were coprecipitated by immunoprecipitation analysis. A pseudotype VSV bearing GP64 produced in human DAF knockdown cells reduced resistance to serum inactivation. In contrast, recombinant baculoviruses generated in insect cells expressing human DAF or carrying the human DAF gene exhibited resistance to complement inactivation. These results suggest that the incorporation of human DAF into viral particles by interacting with baculovirus GP64 is involved in the acquisition of resistance to serum inactivation.
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Hu W, Yu Q, Hu N, Byrd D, Amet T, Shikuma C, Shiramizu B, Halperin JA, Qin X. A high-affinity inhibitor of human CD59 enhances complement-mediated virolysis of HIV-1: implications for treatment of HIV-1/AIDS. THE JOURNAL OF IMMUNOLOGY 2009; 184:359-68. [PMID: 19955519 DOI: 10.4049/jimmunol.0902278] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Many pathogenic enveloped viruses, including HIV-1, escape complement-mediated virolysis by incorporating host cell regulators of complement activation into their own viral envelope. The presence of complement regulators including CD59 on the external surface of the viral envelope confers resistance to complement-mediated virolysis, which may explain why human pathogenic viruses such as HIV-1 are not neutralized by complement in human fluids, even in the presence of high Ab titers against the viral surface proteins. In this study, we report the development of a recombinant form of the fourth domain of the bacterial toxin intermedilysin (the recombinant domain 4 of intermedilysin [rILYd4]), a 114 aa protein that inhibits human CD59 function with high affinity and specificity. In the presence of rILYd4, HIV-1 virions derived from either cell lines or peripheral blood mononuclear cells of HIV-1-infected patients became highly sensitive to complement-mediated lysis activated by either anti-HIV-1 gp120 Abs or by viral infection-induced Abs present in the plasma of HIV-1-infected individuals. We also demonstrated that rILYd4 together with serum or plasma from HIV-1-infected patients as a source of anti-HIV-1 Abs and complement did not mediate complement-mediated lysis of either erythrocytes or peripheral blood mononuclear cells. These results indicate that rILYd4 may represent a novel therapeutic agent against HIV-1/AIDS.
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Affiliation(s)
- Weiguo Hu
- Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
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Shah K. Controlled modulation of Factors H and D. Mol Immunol 2009. [DOI: 10.1016/j.molimm.2009.05.322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Hildgartner A, Wilflingseder D, Gassner C, Dierich MP, Stoiber H, Bánki Z. Induction of complement-mediated lysis of HIV-1 by a combination of HIV-specific and HLA allotype-specific antibodies. Immunol Lett 2009; 126:85-90. [DOI: 10.1016/j.imlet.2009.08.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Revised: 08/11/2009] [Accepted: 08/11/2009] [Indexed: 11/26/2022]
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Xu Y, Zhang C, Jia L, Wen C, Liu H, Wang Y, Sun Y, Huang L, Zhou Y, Song H. A novel approach to inhibit HIV-1 infection and enhance lysis of HIV by a targeted activator of complement. Virol J 2009; 6:123. [PMID: 19671191 PMCID: PMC3224960 DOI: 10.1186/1743-422x-6-123] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Accepted: 08/12/2009] [Indexed: 02/02/2023] Open
Abstract
Background The complement system is one of the most potent weapons of innate immunity. It is not only a mechanism for direct protection against invading pathogens but it also interacts with the adaptive immunity to optimize the pathogen-specific humoral and cellular defense cascades in the body. Complement-mediated lysis of HIV is inefficient but the presence of HIV particles results in complement activation by the generation of many C3-fragments, such as C3dg and C3d. It has been demonstrated that activation of complement can enhance HIV infection through the binding of special complement receptor type 2 expression on the surface of mature B cells and follicular dendritic cells. Presentation of the hypothesis Previous studies have proven that the complement-mediated antibody-dependent enhancement of HIV infection is mediated by the association of complement receptor type 2 bound to the C3 fragment and deposited on the surface of HIV virions. Thus, we hypothesize that a new activator of complement, consisting of a target domain (C3-binding region of complement receptor type 2) linked to a complement-activating human IgG1 Fc domain (CR2-Fc), can target and amplify complement deposition on HIV virions and enhance the efficiency of HIV lysis. Testing the hypothesis Our hypothesis was tested using cell-free HIV-1 virions cultivated in vitro and assessment of virus opsonization was performed by incubating appropriate dilutions of virus with medium containing normal human serum and purified CR2-Fc proteins. As a control group, viruses were incubated with normal human serum under the same conditions. Virus neutralization assays were used to estimate the degree of CR2-Fc-enhanced lysis of HIV compared to untreated virus. Implications of the hypothesis The targeted complement activator, CR2-Fc, can be used as a novel approach to HIV therapy by abrogating the complement-enhanced HIV infection of cells.
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Affiliation(s)
- Yuanyong Xu
- Institute of Disease Control and Prevention, Academy of Military Medical Science, Beijing, PR China.
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The paramyxoviruses simian virus 5 and mumps virus recruit host cell CD46 to evade complement-mediated neutralization. J Virol 2009; 83:7602-11. [PMID: 19457998 DOI: 10.1128/jvi.00713-09] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The complement system is a critical component of the innate immune response that all animal viruses must face during natural infections. Our previous results have shown that treatment of the paramyxovirus simian virus 5 (SV5) with human serum results in deposition of complement C3-derived polypeptides on virion particles. Here, we show that the virion-associated C3 component includes the inactive form iC3b, suggesting that SV5 may have mechanisms to evade the host complement system. Electron microscopy, gradient centrifugation, and Western blot analysis indicated that purified SV5 virions derived from human A549 cells contained CD46, a plasma membrane-expressed regulator of complement that acts as a cofactor for cleavage and inactivation of C3b into iC3b. In vitro cleavage assays with purified complement components showed that SV5 virions had C3b cofactor activity, resulting in specific factor I-mediated cleavage of C3b into inactive iC3b. SV5 particles generated in CHO cells, which do not express CD46, did not have cofactor activity. Conversely, virions derived from a CHO cell line that was engineered to overexpress human CD46 contained elevated levels of virion-associated CD46 and displayed enhanced C3b cofactor activity. In comparison with C3b, purified SV5 virions had very low cofactor activity against C4b, consistent with the known preference of CD46 for C3b versus C4b. Similar results were obtained for the closely related mumps virus (MuV), except that MuV particles derived from CHO-CD46 cells had higher C4b cofactor activity than SV5 virions. In neutralization assays with human serum, SV5 and MuV containing CD46 showed slower kinetics and more resistance to neutralization than SV5 and MuV that lacked CD46. Our results support a model in which the rubulaviruses SV5 and MuV incorporate cell surface complement inhibitors into progeny virions as a mechanism to limit complement-mediated neutralization.
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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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Stoiber H, Soederholm A, Wilflingseder D, Gusenbauer S, Hildgartner A, Dierich MP. Complement and antibodies: a dangerous liaison in HIV infection? Vaccine 2009; 26 Suppl 8:I79-85. [PMID: 19388170 DOI: 10.1016/j.vaccine.2008.11.050] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Due to ongoing recombination and mutations, HIV permanently escapes from neutralizing antibody (nAb) responses of the host. By the masking of epitopes or shedding of gp120, HIV-1 further impedes an efficient neutralization by Abs. Therefore, nAbs responses of the host are chasing behind a rapidly evolving virus and mainly non-neutralizing antibodies (non-nAbs) are present in the host. At the same time, complement deposition on immune-complexed HIV may counteract the immune response by enhancing the infection. On the other hand, complement-mediated lysis is a putative effector mechanism to control viral replication. Here we review the complex interplay between complement, neutralizing and non-neutralizing Abs during HIV infection and discuss the contribution of Abs and complement in blocking versus enhancing the course of infection.
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Affiliation(s)
- Heribert Stoiber
- Department Hygiene and Microbiology, Innsbruck Medical University, Fritz-Preglstr. 3, A-6020 Innsbruck, Austria.
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Willey S, Aasa-Chapman MMI. Humoral immunity to HIV-1: neutralisation and antibody effector functions. Trends Microbiol 2008; 16:596-604. [PMID: 18964020 DOI: 10.1016/j.tim.2008.08.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 08/04/2008] [Accepted: 08/21/2008] [Indexed: 10/21/2022]
Abstract
Several features of HIV have frustrated efforts to develop a vaccine able to induce broadly neutralising antibodies. The enormous genetic diversity of HIV is a major factor, accompanied by the camouflaged nature of the envelope spike, upon which HIV depends for cellular entry and to which antibodies must bind to neutralise. The picture is further complicated by the presence of nonfunctional envelope glycoproteins on the surface of HIV that are immunogenic. Consequently, HIV attracts antibodies that do not directly neutralise the virus but still activate complement and engage Fc receptors, which can both enhance and inhibit infection. The various effects that anti-envelope antibodies have on HIV infection will be reviewed here. Further research is needed to determine if these in vitro-characterised activities have relevance in vivo, and if some of the undesirable effects of non-neutralising antibodies can be avoided or the beneficial effects harnessed.
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Affiliation(s)
- Suzanne Willey
- MRC/UCL Centre for Medical Molecular Virology, Division of Infection and Immunity, University College London, 46 Cleveland Street, London W1T 4JF, UK
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Immune evasion in Kaposi's sarcoma-associated herpes virus associated oncogenesis. Semin Cancer Biol 2008; 18:423-36. [PMID: 18948197 DOI: 10.1016/j.semcancer.2008.09.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Accepted: 09/26/2008] [Indexed: 12/11/2022]
Abstract
A hallmark of herpesviruses is a lifelong persistent infection, which often leads to diseases upon immune suppression of infected host. Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV8), is etiologically linked to the development of Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and Multicentric Castleman's disease (MCD). In order to establish a persistent infection, KSHV dedicates a large portion of its genomic information to sabotage almost every aspect of host immune system. Thus, understanding the interplay between KSHV and the host immune system is important in not only unraveling the complexities of viral persistence and pathogenesis, but also discovering novel therapeutic targets. This review summarizes current knowledge of host immune evasion strategies of KSHV and their contributions to KSHV-associated diseases.
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Potent human immunodeficiency virus-neutralizing and complement lysis activities of antibodies are not obligatorily linked. J Virol 2008; 82:3834-42. [PMID: 18234794 DOI: 10.1128/jvi.02569-07] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To evaluate the contribution of complement-mediated lysis to the in vivo activities of neutralizing antibodies, we analyzed the influence of complement activation on treatment success in a recent passive immunization trial with the neutralizing monoclonal antibodies 2G12, 2F5, and 4E10. Administration of monoclonal antibodies led to an immediate, high activation of the complement system even in the absence of viremia in the 14 participating human immunodeficiency virus-infected individuals. Lysis activity measured in patient plasma increased during passive immunization; however, the increases were modest and only partially attributable to the administration of antibodies. We found that unlike neutralization activity, lysis activity was not associated with treatment success in this trial. Compared to complement lysis mounted by the polyclonal antibody response in vivo, monoclonal antibodies were weak inducers of this activity, suggesting that polyclonal responses are more effective in reaching the required threshold of complement activation. Importantly, strong neutralization activity of the monoclonal antibodies did not predict complement lysis activity against patient and reference viruses, suggesting that these activities are not linked. In summary, our data support the notion that the in vivo activities of 2G12, 2F5, and 4E10 are likely due to direct neutralization or Fc receptor-mediated mechanisms such as phagocytosis and antibody-dependent cellular cytotoxicity.
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