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Sándor N, Schneider AE, Matola AT, Barbai VH, Bencze D, Hammad HH, Papp A, Kövesdi D, Uzonyi B, Józsi M. The human factor H protein family - an update. Front Immunol 2024; 15:1135490. [PMID: 38410512 PMCID: PMC10894998 DOI: 10.3389/fimmu.2024.1135490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 01/08/2024] [Indexed: 02/28/2024] Open
Abstract
Complement is an ancient and complex network of the immune system and, as such, it plays vital physiological roles, but it is also involved in numerous pathological processes. The proper regulation of the complement system is important to allow its sufficient and targeted activity without deleterious side-effects. Factor H is a major complement regulator, and together with its splice variant factor H-like protein 1 and the five human factor H-related (FHR) proteins, they have been linked to various diseases. The role of factor H in inhibiting complement activation is well studied, but the function of the FHRs is less characterized. Current evidence supports the main role of the FHRs as enhancers of complement activation and opsonization, i.e., counter-balancing the inhibitory effect of factor H. FHRs emerge as soluble pattern recognition molecules and positive regulators of the complement system. In addition, factor H and some of the FHR proteins were shown to modulate the activity of immune cells, a non-canonical function outside the complement cascade. Recent efforts have intensified to study factor H and the FHRs and develop new tools for the distinction, quantification and functional characterization of members of this protein family. Here, we provide an update and overview on the versatile roles of factor H family proteins, what we know about their biological functions in healthy conditions and in diseases.
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Affiliation(s)
- Noémi Sándor
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
- HUN-REN-ELTE Complement Research Group, Hungarian Research Network, Budapest, Hungary
| | | | | | - Veronika H. Barbai
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Dániel Bencze
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Hani Hashim Hammad
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Alexandra Papp
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Dorottya Kövesdi
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
- HUN-REN-ELTE Complement Research Group, Hungarian Research Network, Budapest, Hungary
| | - Barbara Uzonyi
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
- HUN-REN-ELTE Complement Research Group, Hungarian Research Network, Budapest, Hungary
| | - Mihály Józsi
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
- HUN-REN-ELTE Complement Research Group, Hungarian Research Network, Budapest, Hungary
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2
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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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Murugaiah V, Varghese PM, Beirag N, DeCordova S, Sim RB, Kishore U. Complement Proteins as Soluble Pattern Recognition Receptors for Pathogenic Viruses. Viruses 2021; 13:v13050824. [PMID: 34063241 PMCID: PMC8147407 DOI: 10.3390/v13050824] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 04/28/2021] [Indexed: 12/11/2022] Open
Abstract
The complement system represents a crucial part of innate immunity. It contains a diverse range of soluble activators, membrane-bound receptors, and regulators. Its principal function is to eliminate pathogens via activation of three distinct pathways: classical, alternative, and lectin. In the case of viruses, the complement activation results in effector functions such as virion opsonisation by complement components, phagocytosis induction, virolysis by the membrane attack complex, and promotion of immune responses through anaphylatoxins and chemotactic factors. Recent studies have shown that the addition of individual complement components can neutralise viruses without requiring the activation of the complement cascade. While the complement-mediated effector functions can neutralise a diverse range of viruses, numerous viruses have evolved mechanisms to subvert complement recognition/activation by encoding several proteins that inhibit the complement system, contributing to viral survival and pathogenesis. This review focuses on these complement-dependent and -independent interactions of complement components (especially C1q, C4b-binding protein, properdin, factor H, Mannose-binding lectin, and Ficolins) with several viruses and their consequences.
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Affiliation(s)
- Valarmathy Murugaiah
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK; (V.M.); (P.M.V.); (N.B.); (S.D.)
| | - Praveen M. Varghese
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK; (V.M.); (P.M.V.); (N.B.); (S.D.)
| | - Nazar Beirag
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK; (V.M.); (P.M.V.); (N.B.); (S.D.)
| | - Syreeta DeCordova
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK; (V.M.); (P.M.V.); (N.B.); (S.D.)
| | - Robert B. Sim
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK;
| | - Uday Kishore
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK; (V.M.); (P.M.V.); (N.B.); (S.D.)
- Correspondence: or
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4
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Moore SR, Menon SS, Cortes C, Ferreira VP. Hijacking Factor H for Complement Immune Evasion. Front Immunol 2021; 12:602277. [PMID: 33717083 PMCID: PMC7947212 DOI: 10.3389/fimmu.2021.602277] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 01/15/2021] [Indexed: 12/15/2022] Open
Abstract
The complement system is an essential player in innate and adaptive immunity. It consists of three pathways (alternative, classical, and lectin) that initiate either spontaneously (alternative) or in response to danger (all pathways). Complement leads to numerous outcomes detrimental to invaders, including direct killing by formation of the pore-forming membrane attack complex, recruitment of immune cells to sites of invasion, facilitation of phagocytosis, and enhancement of cellular immune responses. Pathogens must overcome the complement system to survive in the host. A common strategy used by pathogens to evade complement is hijacking host complement regulators. Complement regulators prevent attack of host cells and include a collection of membrane-bound and fluid phase proteins. Factor H (FH), a fluid phase complement regulatory protein, controls the alternative pathway (AP) both in the fluid phase of the human body and on cell surfaces. In order to prevent complement activation and amplification on host cells and tissues, FH recognizes host cell-specific polyanionic markers in combination with complement C3 fragments. FH suppresses AP complement-mediated attack by accelerating decay of convertases and by helping to inactivate C3 fragments on host cells. Pathogens, most of which do not have polyanionic markers, are not recognized by FH. Numerous pathogens, including certain bacteria, viruses, protozoa, helminths, and fungi, can recruit FH to protect themselves against host-mediated complement attack, using either specific receptors and/or molecular mimicry to appear more like a host cell. This review will explore pathogen complement evasion mechanisms involving FH recruitment with an emphasis on: (a) characterizing the structural properties and expression patterns of pathogen FH binding proteins, as well as other strategies used by pathogens to capture FH; (b) classifying domains of FH important in pathogen interaction; and (c) discussing existing and potential treatment strategies that target FH interactions with pathogens. Overall, many pathogens use FH to avoid complement attack and appreciating the commonalities across these diverse microorganisms deepens the understanding of complement in microbiology.
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Affiliation(s)
- Sara R Moore
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Smrithi S Menon
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Claudio Cortes
- Department of Foundational Medical Sciences, Oakland University William Beaumont School of Medicine, Rochester, MI, United States
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
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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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6
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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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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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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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Berra S, Clivio A. Rapid isolation of pure Complement Factor H from serum for functional studies by the use of a monoclonal antibody that discriminates FH from all the other isoforms. Mol Immunol 2016; 72:65-73. [PMID: 26972487 DOI: 10.1016/j.molimm.2016.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 02/26/2016] [Accepted: 03/01/2016] [Indexed: 11/30/2022]
Abstract
Several mutations have been identified in the gene coding for Complement Factor H (FH) from patients with atypical Hemolytic Uraemic Syndrome (aHUS), Age-related Macular Degeneration (AMD) and Membranoproliferative Glomerulonephritis (MPGN). These data allow for a precise description of the structural changes affecting FH, but a simple test for specifically assessing FH function routinely is not yet of common use. We have produced and characterised a monoclonal antibody (5H5) which discriminates between FH and the smaller FH-like 1 and FH-related proteins and show here that it specifically binds to FH without detecting the smaller isoforms. We therefore used this mAb for a quick, one-step micro-purification of FH directly from control sera and showed that this affinity chromatography procedure is not disruptive of its cofactor function. We also developed a modified sheep erythrocytes haemolysis test using our antibody and affinity-purified FH. These tests can be used in conjunction for assessing the function of FH purified from patients affected by FH-related diseases. Moreover we used this mAb to develop a FH-specific ELISA test.
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Affiliation(s)
- Silvia Berra
- "L. Sacco" Department of Biomedical and Clinical Sciences (DIBIC), University of Milan, Italy.
| | - Alberto Clivio
- "L. Sacco" Department of Biomedical and Clinical Sciences (DIBIC), University of Milan, Italy
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Shetty V, Jain P, Nickens Z, Sinnathamby G, Mehta A, Philip R. Investigation of plasma biomarkers in HIV-1/HCV mono- and coinfected individuals by multiplex iTRAQ quantitative proteomics. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2012; 15:705-17. [PMID: 21978398 DOI: 10.1089/omi.2011.0004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The analysis of plasma samples from HIV-1/HCV mono- and coinfected individuals by quantitative proteomics is an efficient strategy to investigate changes in protein abundances and to characterize the proteins that are the effectors of cellular functions involved in viral pathogenesis. In this study, the infected and healthy plasma samples (in triplicate) were treated with ProteoMiner beads to equalize protein concentrations and subjected to 4-plex iTRAQ labeling and liquid chromatography/mass spectrometry (LC-MS/MS) analysis. A total of 70 proteins were identified with high confidence in the triplicate analysis of plasma proteins and 65% of the proteins were found to be common among the three replicates. Apolipoproteins and complement proteins are the two major classes of proteins that exhibited differential regulation. The results of quantitative analysis revealed that APOA2, APOC2, APOE, C3, HRG proteins were upregulated in the plasma of all the three HIV-1 mono-, HCV mono-, and coinfected patient samples compared to healthy control samples. Ingenuity pathway analysis (IPA) of the upregulated proteins revealed that they are implicated in the hepatic lipid metabolism, inflammation, and acute-phase response signaling pathways. Thus, we identified several differentially regulated proteins in HIV-1/HCV mono and coinfected plasma samples that may be potential biomarkers for liver disease.
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Affiliation(s)
- Vivekananda Shetty
- Immunotope, Inc., Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
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12
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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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13
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Ferreira VP, Pangburn MK, Cortés C. Complement control protein factor H: the good, the bad, and the inadequate. Mol Immunol 2010; 47:2187-97. [PMID: 20580090 DOI: 10.1016/j.molimm.2010.05.007] [Citation(s) in RCA: 298] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The complement system is an essential component of the innate immune system that participates in elimination of pathogens and altered host cells and comprises an essential link between the innate and adaptive immune system. Soluble and membrane-bound complement regulators protect cells and tissues from unintended complement-mediated injury. Complement factor H is a soluble complement regulator essential for controlling the alternative pathway in blood and on cell surfaces. Normal recognition of self-cell markers (i.e. polyanions) and C3b/C3d fragments is necessary for factor H function. Inadequate recognition of host cell surfaces by factor H due to mutations and polymorphisms have been associated with complement-mediated tissue damage and disease. On the other hand, unwanted recognition of pathogens and altered self-cells (i.e. cancer) by factor H is used as an immune evasion strategy. This review will focus on the current knowledge related to these versatile recognition properties of factor H.
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Affiliation(s)
- Viviana P Ferreira
- Department of Medical Microbiology and Immunology, College of Medicine, University of Toledo, Toledo, OH 43614, United States.
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14
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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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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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16
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Ngampasutadol J, Ram S, Gulati S, Agarwal S, Li C, Visintin A, Monks B, Madico G, Rice PA. Human factor H interacts selectively with Neisseria gonorrhoeae and results in species-specific complement evasion. THE JOURNAL OF IMMUNOLOGY 2008; 180:3426-35. [PMID: 18292569 DOI: 10.4049/jimmunol.180.5.3426] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Complement forms a key arm of innate immune defenses against gonococcal infection. Sialylation of gonococcal lipo-oligosaccharide, or expression of porin 1A (Por1A) protein, enables Neisseria gonorrhoeae to bind the alternative pathway complement inhibitor, factor H (fH), and evade killing by human complement. Using recombinant fH fragment-murine Fc fusion proteins, we localized two N. gonorrhoeae Por1A-binding regions in fH: one in complement control protein domain 6, the other in complement control proteins 18-20. The latter is similar to that reported previously for sialylated Por1B gonococci. Upon incubation with human serum, Por1A and sialylated Por1B strains bound full-length human fH (HufH) and fH-related protein 1. In addition, Por1A strains bound fH-like protein 1 weakly. Only HufH, but not fH from other primates, bound directly to gonococci. Consistent with direct HufH binding, unsialylated Por1A gonococci resisted killing only by human complement, but not complement from other primates, rodents or lagomorphs; adding HufH to these heterologous sera restored serum resistance. Lipo-oligosaccharide sialylation of N. gonorrhoeae resulted in classical pathway regulation as evidenced by decreased C4 binding in human, chimpanzee, and rhesus serum but was accompanied by serum resistance only in human and chimpanzee serum. Direct-binding specificity of HufH only to gonococci that prevents serum killing is restricted to humans and may in part explain species-specific restriction of natural gonococcal infection. Our findings may help to improve animal models for gonorrhea while also having implications in the choice of complement sources to evaluate neisserial vaccine candidates.
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Affiliation(s)
- Jutamas Ngampasutadol
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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17
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Cummings KL, Waggoner SN, Tacke R, Hahn YS. Role of complement in immune regulation and its exploitation by virus. Viral Immunol 2008; 20:505-24. [PMID: 18158725 DOI: 10.1089/vim.2007.0061] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Complement is activated during the early phase of viral infection and promotes destruction of virus particles as well as the initiation of inflammatory responses. Recently, complement and complement receptors have been reported to play an important role in the regulation of innate as well as adaptive immune responses during infection. The regulation of host immune responses by complement involves modulation of dendritic cell activity in addition to direct effects on T-cell function. Intriguingly, many viruses encode homologs of complement regulatory molecules or proteins that interact with complement receptors on antigen-presenting cells and lymphocytes. The evolution of viral mechanisms to alter complement function may augment pathogen persistence and limit immune-mediated tissue destruction. These observations suggest that complement may play an important role in both innate and adaptive immune responses to infection as well as virus-mediated modulation of host immunity.
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Affiliation(s)
- Kara L Cummings
- Beirne Carter Center for Immunology Research and Department of Microbiology, University of Virginia, Charlottesville, Virginia
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18
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Abstract
Humoral immunity is considered a key component of effective vaccines against HIV-1. Hence, an enormous effort has been put into investigating the neutralizing antibody response to HIV-1 over the past 20 years which generated key information on epitope specificity, potency, breadth and in vivo activity of the neutralizing antibodies. Less clear is still the role of antibody-mediated effector functions (antibody-dependent cellular cytotoxicity, phagocytosis, complement system) and uncertainty prevails whether Fc-mediated mechanisms are largely beneficial or detrimental for the host. The current knowledge on the manifold functions of the humoral immune response in HIV infection, their underlying mechanisms and potential in vaccine-induced immunity will be discussed in this review.
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Affiliation(s)
- M Huber
- Division of Infectious Diseases, University Hospital Zurich, Zurich, Switzerland
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19
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Iglesias E, Thompson R, Carrazana Y, Lobaina Y, García D, Sánchez J, García J, Cruz O, Brown E, Martin A, Muzio VL, Aguilar JC. Coinoculation with hepatitis B surface and core antigen promotes a Th1 immune response to a multiepitopic protein of HIV-1. Immunol Cell Biol 2006; 84:174-83. [PMID: 16519735 DOI: 10.1111/j.1440-1711.2005.01408.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
It has been defined that strong and multispecific cellular immune responses correlate with a better prognosis during the course of chronic diseases. A cross-enhancing effect on the resulting immune response obtained by the coadministration of recombinant hepatitis B virus (HBV) surface and core Ag was recently observed. With the objective of studying the effect of such Ag on the immune response to coinoculated heterologous Ag and vice versa, several formulations containing the recombinant HBV Ag and a multiepitopic protein (CR3) composed by CTL and Th epitopes from HIV-1 were evaluated by s.c. and mucosal administration. Combinations of two and three Ag were evaluated for cellular and humoral immune responses. The results showed that the best Ag combination for nasal immunization was the mixture comprising the CR3 recombinant HIV protein and both HBV Ag. Similarly, it was also the best formulation for s.c. immunization in aluminium phosphate adjuvant. In conclusion, it is possible to induce a Th1 stimulation of the cellular immune response specific for a HIV-based recombinant protein by formulating this Ag with the recombinant HBV Ag.
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20
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Bánki Z, Stoiber H, Dierich MP. HIV and human complement: inefficient virolysis and effective adherence. Immunol Lett 2004; 97:209-14. [PMID: 15752560 DOI: 10.1016/j.imlet.2004.11.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2004] [Revised: 11/08/2004] [Accepted: 11/08/2004] [Indexed: 02/02/2023]
Abstract
Both, HIV envelope proteins gp120 and gp41 can directly activate complement system, even in the absence of HIV-specific antibodies. During the budding process HIV acquires host membrane-associated molecules among these complement regulatory proteins (CRPs). The presence of CRPs on the viral surface rescues HIV from complement-mediated virolysis. The inefficient virolysis results in the deposition of complement-fragments on the viral surface allowing interactions of HIV with complement receptor expressing cells. In this review, the interaction of HIV with the complement system and the consequences of complement opsonisation on virus infection will be discussed.
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Affiliation(s)
- Zoltán Bánki
- Department of Hygiene, Microbiology and Social Medicine, Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria and Ludwig-Boltzmann-Institute for AIDS research, Fritz-Pregl-Str. 3., 6020 Innsbruck, Austria
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21
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Stoiber H, Speth C, Dierich MP. Role of complement in the control of HIV dynamics and pathogenesis. Vaccine 2003; 21 Suppl 2:S77-82. [PMID: 12763687 DOI: 10.1016/s0264-410x(03)00203-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In all ex vivo preparations of HIV tested so far, C3 fragments and, after seroconversion, antibodies were detected on the viral surface. This indicates that HIV survives complement-mediated lysis. The virus has adopted different protection mechanisms to keep complement activation under the threshold necessary to induce virolysis. Among them are complement regulatory proteins that remain functionally active on the surface of HIV and turn down the complement cascade and serum proteins with complement regulatory activities. Therefore, opsonized virions accumulate in HIV-infected individuals, and subsequently adhere to complement receptor (CR) expressing cells. Among them are B cells, which bind opsonized virus. Such bound virus is efficiently transferred to autologous T cells, which subsequently are infected. Other cells interacting via CR with opsonized HIV are follicular dendritic cells (FDC). As shown by ex vivo experiments, up to 80% of virus is bound to follicular dendritic cells through C3-CR interactions. In the brain, HIV is not only interacting with complement proteins, but is able to induce their expression. Thus, interaction of HIV with the complement system is a main mechanism for pathogenesis to AIDS, since retention of (complement-resistant) opsonized viral particles on cell surfaces via CRs occurs in different compartments in HIV-infected individuals, thereby promoting transmission of virus to other permissive cells.
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Affiliation(s)
- Heribert Stoiber
- Institute of Hygiene and Social Medicine and Ludwig Boltzmann Institute for AIDS Research, University Innsbruck, Fritz Pregl-Strasse 3, A-6020 Innsbruck, Austria.
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22
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Abstract
The complement system is a potent innate immune mechanism consisting of cascades of proteins which are designed to fight against and annul intrusion of all the foreign pathogens. Although viruses are smaller in size and have relatively simple structure, they are not immune to complement attack. Thus, activation of the complement system can lead to neutralization of cell-free viruses, phagocytosis of C3b-coated viral particles, lysis of virus-infected cells, and generation of inflammatory and specific immune responses. However, to combat host responses and succeed as pathogens, viruses not only have developed/adopted mechanisms to control complement, but also have turned these interactions to their own advantage. Important examples include poxviruses, herpesviruses, retroviruses, paramyxoviruses and picornaviruses. In this review, we provide information on the various complement evasion strategies that viruses have developed to thwart the complement attack of the host. A special emphasis is given on the interactions between the viral proteins that are involved in molecular mimicry and the complement system.
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Affiliation(s)
- John Bernet
- National Centre for Cell Science, Pune University Campus, 411 007 Ganeshkhind, Pune, India
| | - Jayati Mullick
- National Centre for Cell Science, Pune University Campus, 411 007 Ganeshkhind, Pune, India
| | - Akhilesh K. Singh
- National Centre for Cell Science, Pune University Campus, 411 007 Ganeshkhind, Pune, India
| | - Arvind Sahu
- National Centre for Cell Science, Pune University Campus, 411 007 Ganeshkhind, Pune, India
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23
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Stoiber H, Ammann C, Spruth M, Müllauer B, Eberhart A, Harris CL, Huber CG, Longhi R, Falkensammer B, Würzner R, Dierich MP. Enhancement of complement-mediated lysis by a peptide derived from SCR 13 of complement factor H. Immunobiology 2001; 203:670-86. [PMID: 11402501 DOI: 10.1016/s0171-2985(01)80016-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Complement factor H (fH) is an important regulator of complement activation. It contributes to protection of cells against homologous complement attack. In this study we tested the effect of fH-depletion of normal human serum (NHS) on lysis of antibody-coated sheep and human erythrocytes (EshA and EhuA). In the absence of fH, lysis of sensitised Esh and Ehu was clearly increased. Addition of fH to fH-depleted serum re-established protection of cells against complement similar to that seen with NHS. A fH-derived peptide (pepAred), covering the N-terminal half of SCR 13 in fH, was able to enhance complement-mediated lysis of EhuA significantly. However, the oxidised form of this peptide (pepAox) had no effect. Biotinylated pepAred, but not pepAox, was able to directly bind to cells. Additionally, pepAred competed with direct fH-cell interaction which was observable only after treatment of purified fH with mercaptoethanol. Only pepAred increased the amount of C3 fragments and reduced levels of fH detectable on cells as shown by FACS analysis and radio-immuno assay. Furthermore, fH and factor I (fI)-mediated cleavage of agarose bound C3b into iC3b was decreased in the presence of pepAred. These data indicate that a fH-derived peptide can enhance complement-mediated lysis. We will continue to investigate whether the use of a fH peptide can be exploited for therapeutical purposes.
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Affiliation(s)
- H Stoiber
- Institute of Hygiene and Social Medicine, Innsbruck, Austria.
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24
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25
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Abstract
Retroviral vectors have become a standard tool for gene transfer technology. Compared with other gene transfer systems, retroviral vectors have several advantages, including their ability to transduce a variety of cell types, to integrate efficiently into the genomic DNA of the recipient cells and to express the transduced gene at high levels. The relatively well understood biology of retroviruses has made possible the development of packaging cell lines which provide in trans all the viral proteins required for viral particle formation. The design of different types of packaging cells has evolved to reduce the possibility of helper virus production. The host range of retroviruses has been expanded by pseudotyping the vectors with heterologous viral glycoproteins and receptor-specific ligands. The development of lentivirus vectors has allowed efficient gene transfer to quiescent cells. This review describes different strategies adopted for developing vectors to be used in gene therapy applications.
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Affiliation(s)
- G Palù
- Department of Histology, Microbiology and Medical Biotechnologies, University of Padova, Italy
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26
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Pintér C, Beltrami S, Stoiber H, Negri DR, Titti F, Clivio A. Interference with complement regulatory molecules as a possible therapeutic strategy in HIV infection. Expert Opin Investig Drugs 2000; 9:199-205. [PMID: 11060671 DOI: 10.1517/13543784.9.2.199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Drugs which inhibit different stages of the HIV infection process, such as cell entry through CD4 and chemokine receptors, production of double stranded DNA from the HIV genome and maturation of newly produced viruses, are now proposed for AIDS therapy. None of these treatments, however, solve the problem of complete HIV eradication and the frequent appearance of mutants displaying drug resistance. We have recently detailed a strategy describing how HIV protects itself from the human complement and propose that interference of this resistance could be a possible target for therapy.
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Affiliation(s)
- C Pintér
- Department of Preclinical Sciences, University of Milano, via G.B. Grassi, 74, I-20157 Milano, Italy
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27
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Ram S, Mackinnon FG, Gulati S, McQuillen DP, Vogel U, Frosch M, Elkins C, Guttormsen HK, Wetzler LM, Oppermann M, Pangburn MK, Rice PA. The contrasting mechanisms of serum resistance of Neisseria gonorrhoeae and group B Neisseria meningitidis. Mol Immunol 1999; 36:915-28. [PMID: 10698346 DOI: 10.1016/s0161-5890(99)00114-5] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Neisseria gonorrhoeae and Neisseria meningitidis have evolved intricate mechanisms to evade complement-mediated killing. Sialylation of gonococcal lipooligosaccharide (LOS) results in conversion of previously serum sensitive strains to unstable serum resistance, which is mediated by factor H binding. Porin (Por) is also instrumental in mediating stable serum resistance in gonococci. The 5th loop of certain gonococcal PorlAs binds factor H, which efficiently inactivates C3b to iC3b. Factor H glycan residues may be essential for factor H binding to certain Por1A strains. Por1A strains can also regulate the classical pathway by binding to C4b-binding protein (C4bp) probably via the 1st loop of the Por molecule. Certain serum resistant Por1 B strains can also regulate complement by binding C4bp through a loop other than loop 1. Purified C4b can inhibit binding of C4bp to Por 1B, but not Por1A, suggesting different binding sites on C4bp for the two Por types. Unlike serum resistant gonococci, resistant meningococci have abundant C3b on their surface, which is only partially processed to iC3b. The main mechanism of complement evasion by group B meningococci is inhibition of membrane attack complex (MAC) insertion by their polysaccharide capsule. LOS structure may act in concert with capsule to prevent MAC insertion. Meningococcal strains with Class 3 Por preferentially bind factor H, suggesting Class 3 Por acts as a receptor for factor H.
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Affiliation(s)
- S Ram
- The Maxwell Finland Laboratory for Infectious Diseases, Boston Medical Center, MA 02118, USA.
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28
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Ram S, McQuillen DP, Gulati S, Elkins C, Pangburn MK, Rice PA. Binding of complement factor H to loop 5 of porin protein 1A: a molecular mechanism of serum resistance of nonsialylated Neisseria gonorrhoeae. J Exp Med 1998; 188:671-80. [PMID: 9705949 PMCID: PMC2213355 DOI: 10.1084/jem.188.4.671] [Citation(s) in RCA: 204] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/1998] [Revised: 06/02/1998] [Indexed: 01/15/2023] Open
Abstract
Neisseria gonorrhoeae isolated from patients with disseminated infection are often of the porin (Por1A) serotype and resist killing by nonimmune normal human serum. The molecular basis of this resistance (termed stable serum resistance) in these strains has not been fully defined but is not related to sialylation of lipooligosaccharide. Here we demonstrate that Por1A bearing gonococcal strains bind more factor H, a critical downregulator of the alternative complement pathway, than their Por1B counterparts. This results in a sevenfold reduction in C3b, which is >75% converted to iC3b. Factor H binding to isogenic gonococcal strains that differed only in their porin serotype, confirmed that Por1A was the acceptor molecule for factor H. We identified a surface exposed region on the Por1A molecule that served as the binding site for factor H. We used gonococcal strains with hybrid Por1A/B molecules that differed in their surface exposed domains to localize the factor H binding site to loop 5 of Por1A. This was confirmed by inhibition of factor H binding using synthetic peptides corresponding to the putative exposed regions of the porin loops. The addition of Por1A loop 5 peptide in a serum bactericidal assay, which inhibited binding of factor H to the bacterial surface, permitted 50% killing of an otherwise completely serum resistant gonococcal strain. Collectively, these data provide a molecular basis to explain serum resistance of Por1A strains of N. gonorrhoeae.
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Affiliation(s)
- S Ram
- The Maxwell Finland Laboratory for Infectious Diseases and the Evans Memorial Department of Clinical Research and Department of Medicine, Boston Medical Center, Boston, Massachusetts 02118, USA.
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29
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Ram S, Sharma AK, Simpson SD, Gulati S, McQuillen DP, Pangburn MK, Rice PA. A novel sialic acid binding site on factor H mediates serum resistance of sialylated Neisseria gonorrhoeae. J Exp Med 1998; 187:743-52. [PMID: 9480984 PMCID: PMC2212180 DOI: 10.1084/jem.187.5.743] [Citation(s) in RCA: 303] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/1997] [Indexed: 02/06/2023] Open
Abstract
Factor H (fH), a key alternative complement pathway regulator, is a cofactor for factor I-mediated cleavage of C3b. fH consists of 20 short consensus repeat (SCR) domains. Sialic acid binding domains have previously been localized to fH SCRs 6-10 and 13. To examine fH binding on a sialylated microbial surface, we grew Neisseria gonorrhoeae in the presence of 5'-cytidinemonophospho-N-acetylneuraminic acid, which sialylates lipooligosaccharide and converts to serum resistance gonococci previously sensitive to nonimmune serum killing. fH domains necessary for binding sialylated gonococci were determined by incubating organisms with recombinant human fH (rH) and nine mutant rH molecules (deletions spanning the entire fH molecule). rH and all mutant rH molecules that contained SCRs 16-20 bound to the sialylated strain; no mutant molecule bound to serum-sensitive nonsialylated organisms. Sialic acid was demonstrated to be the fH target by flow cytometry that showed a fourfold increase in fH binding that was reversed by neuraminidase-mediated cleavage of sialic acid off gonococci. Functional specificity of fH was confirmed by decreased total C3 binding and almost complete conversion to iC3b on sialylated gonococci. Sialic acid can therefore bind fH uniquely through SCRs 16-20. This blocks complement pathway activation for N. gonorrhoeae at the level of C3.
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Affiliation(s)
- S Ram
- The Maxwell Finland Laboratory for Infectious Diseases, Boston Medical Center, Boston, Massachusetts 02118, USA.
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30
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Montefiori DC. Role of complement and Fc receptors in the pathogenesis of HIV-1 infection. SPRINGER SEMINARS IN IMMUNOPATHOLOGY 1997; 18:371-90. [PMID: 9089955 DOI: 10.1007/bf00813504] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- D C Montefiori
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
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31
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Abstract
In human plasma, HIV activates the complement system, even in the absence of specific antibodies. Complement activation would, however, be harmful to the virus if the reactions were allowed to go to completion, since their final outcome would be virolysis. This is avoided by complement regulatory molecules, which either are included in the virus membrane upon budding from the infected cells (e.g. DAF/CD55) or are secondarily attached to HIV envelope glycoproteins as in the case of factor H. By using this strategy of interaction with complement components, HIV takes advantage of human complement activation for enhancement of infectivity, for follicular localization, and for broadening its target cell range at the same time that it displays an intrinsic resistance against the lytic action of human complement. This intrinsic resistance to complement-mediated virolysis can be overcome by monoclonal antibodies inhibiting recruitment of human factor H to the virus surface, suggesting a new therapeutic principle.
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Affiliation(s)
- H Stoiber
- Institut für Hygiene, Innsbruck, Austria.
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32
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Dierich MP, Frank I, Stoiber H, Clivio A, Spruth M, Steindl F, Katinger HW. The envelope of HIV. Immunol Lett 1996; 54:205-6. [PMID: 9052879 DOI: 10.1016/s0165-2478(96)02674-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- M P Dierich
- Institut fur Hygiene, University of Innsbruck, Austria
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33
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Abstract
The human immunodeficiency virus uses the human complement system to its advantage. Is it possible to turn the tables with a vaccine?
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Affiliation(s)
- M P Dierich
- Institut für Hygiene and Ludwig Boltzmann Institut für AIDS-Forschung, Innsbruck, Austria
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34
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Stoiber H, Pintér C, Siccardi AG, Clivio A, Dierich MP. Efficient destruction of human immunodeficiency virus in human serum by inhibiting the protective action of complement factor H and decay accelerating factor (DAF, CD55). J Exp Med 1996; 183:307-10. [PMID: 8551237 PMCID: PMC2192395 DOI: 10.1084/jem.183.1.307] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Activation of the human complement system leads to complement deposition on human immunodeficiency virus (HIV) and HIV-infected cells without causing efficient complement-mediated lysis. Even in the presence of HIV-specific antibodies, only a few particles are destroyed, demonstrating that HIV is intrinsically resistant to human complement. Here we report that, in addition to decay accelerating factor (DAF) being partially responsible, human complement factor H (CFH), a humoral negative regulator of complement activation, is most critical for this resistance. In the presence of HIV-specific antibodies, sera devoid of CFH (total genetic deficiency or normal human serum depleted of CFH by affinity chromatography) lysed free virus and HIV-infected but not uninfected cells. In the presence of CFH, lysis of HIV was only obtained when binding of CFH to gp41 was inhibited by a monoclonal antibody against a main CFH-binding site in gp41. Since CFH is an abundant protein in serum, and high local concentration of CFH can be obtained at the surface of HIV as the result of specific interactions of CFH with the HIV envelope, it is proposed that the resistance of HIV and HIV-infected cells against complement-mediated lysis in vivo is dependent on DAF and CFH and can be overcome by suppressing this protection. Neutralization of HIV may be achieved by antibodies against DAF and, more importantly, antibodies against CFH-binding sites on HIV envelope proteins.
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Affiliation(s)
- H Stoiber
- Institut für Hygiene, Ludwig Boltzmann Institut für AIDS Forschung, Innsbruck, Austria
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35
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Wu SC, Spouge JL, Conley SR, Tsai WP, Merges MJ, Nara PL. Human plasma enhances the infectivity of primary human immunodeficiency virus type 1 isolates in peripheral blood mononuclear cells and monocyte-derived macrophages. J Virol 1995; 69:6054-62. [PMID: 7666510 PMCID: PMC189502 DOI: 10.1128/jvi.69.10.6054-6062.1995] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Physiological microenvironments such as blood, seminal plasma, mucosal secretions, or lymphatic fluids may influence the biology of the virus-host cell and immune interactions for human immunodeficiency virus type 1 (HIV-1). Relative to media, physiological levels of human plasma were found to enhance the infectivity of HIV-1 primary isolates in both phytohemagglutinin-stimulated peripheral blood mononuclear cells and monocyte-derived macrophages. Enhancement was observed only when plasma was present during the virus-cell incubation and resulted in a 3- to 30-fold increase in virus titers in all of the four primary isolates tested. Both infectivity and virion binding experiments demonstrated a slow, time-dependent process generally requiring between 1 and 10 h. Human plasma collected in anticoagulants CPDA-1 and heparin, but not EDTA, exhibited this effect at concentrations from 90 to 40%. Furthermore, heat-inactivated plasma resulted in a loss of enhancement in peripheral blood mononuclear cells but not in monocyte-derived macrophages. Physiological concentrations of human plasma appear to recruit additional infectivity, thus increasing the infectious potential of the virus inoculum.
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Affiliation(s)
- S C Wu
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, Maryland 20894, USA
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36
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Pintér C, Siccardi AG, Lopalco L, Longhi R, Clivio A. HIV glycoprotein 41 and complement factor H interact with each other and share functional as well as antigenic homology. AIDS Res Hum Retroviruses 1995; 11:971-80. [PMID: 7492444 DOI: 10.1089/aid.1995.11.971] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
We have shown that complement factor H (CFH) interacts with HIV-1 at the level of the sequence Env 105-119, contained in the C1 domain of gp120. CFH interaction with HIV was evident only after dissociation of the Env complex induced by exposure to sCD4. We hypothesized that CFH could act as a gp41 analog in the interaction with Env 105-119. A panel of partially overlapping, synthetic peptides reproducing the extracellular portion of gp41 was therefore used to compete the binding of CFH to Env 105-119. Three sets of peptides that competed this interaction were identified. These peptides defined a region of functional homology between the gp41 molecule and CFH (Env 580-600), and two regions of interaction (Env 620-640 and Env 650-670). In addition to this, a monoclonal antibody directed against peptide Env 580-600 and a polyclonal mouse antiserum raised against recombinant gp41 were shown to recognize CFH in Western blots and ELISA, respectively, also defining a region of antigenic homology between gp41 and CFH. These data provide evidence for interaction and molecular mimicry between an HIV structural protein and a negative regulator of the complement pathway. We show here that CFH can interact with both HIV Env proteins, suggesting a possible and efficient mechanism of downregulation of the complement cascade at the surface of infected cells.
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Affiliation(s)
- C Pintér
- Dipartimento di Biologia e Genetica per le Scienze Mediche, L.I.T.A. Vialba, Università degli Studi di Milano, Italy
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