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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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Menon SS, Ramirez-Toloza G, Wycoff KL, Ehinger S, Shaughnessy J, Ram S, Ferreira VP. Mechanisms by which Factor H protects Trypanosoma cruzi from the alternative pathway of complement. Front Immunol 2024; 15:1152000. [PMID: 38361922 PMCID: PMC10867245 DOI: 10.3389/fimmu.2024.1152000] [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: 01/27/2023] [Accepted: 01/16/2024] [Indexed: 02/17/2024] Open
Abstract
Chagas disease, a chronic disabling disease caused by the protozoan Trypanosoma cruzi, has no standardized treatment or preventative vaccine. The infective trypomastigote form of T. cruzi is highly resistant to killing by the complement immune system. Factor H (FH), a negative regulator of the alternative pathway (AP) of complement on cell surfaces and in blood, contains 20 short consensus repeat domains. The four N-terminal domains of FH inactivate the AP, while the other domains interact with C3b/d and glycan markers on cell surfaces. Various pathogens bind FH to inactivate the AP. T. cruzi uses its trans-sialidase enzyme to transfer host sialic acids to its own surface, which could be one of the approaches it uses to bind FH. Previous studies have shown that FH binds to complement-opsonized T. cruzi and parasite desialylation increases complement-mediated lysis of trypomastigotes. However, the molecular basis of FH binding to T. cruzi remain unknown. Only trypomastigotes, but not epimastigotes (non-infective, complement susceptible) bound FH directly, independent of C3 deposition, in a dose-dependent manner. Domain mapping experiments using 3-5 FH domain fragments showed that domains 5-8 competitively inhibited FH binding to the trypomastigotes by ~35% but did not decrease survival in complement. FH-Fc or mutant FH-Fc fusion proteins (3-11 contiguous FH domains fused to the IgG Fc) also did not kill trypomastigotes. FH-related protein-5, whose domains bear significant sequence identity to all known polyanion-binding FH domains (6-7, 10-14, 19-20), fully inhibited FH binding to trypomastigotes and reduced trypomastigote survival to < 24% in the presence of serum. In conclusion, we have elucidated the role of FH in complement resistance of trypomastigotes.
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Affiliation(s)
- Smrithi S. Menon
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Galia Ramirez-Toloza
- Laboratory of Parasitology, Department of Animal Preventive Medicine, Faculty of Veterinary Medicine and Livestock Sciences, University of Chile, Santiago, Chile
| | | | - Sean Ehinger
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA, United States
| | - Sanjay Ram
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA, 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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Su YC, Kadari M, Straw ML, Janoušková M, Jonsson S, Thofte O, Jalalvand F, Matuschek E, Sandblad L, Végvári Á, Zubarev RA, Riesbeck K. Non-typeable Haemophilus influenzae major outer membrane protein P5 contributes to bacterial membrane stability, and affects the membrane protein composition crucial for interactions with the human host. Front Cell Infect Microbiol 2023; 13:1085908. [PMID: 37305414 PMCID: PMC10250671 DOI: 10.3389/fcimb.2023.1085908] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 04/10/2023] [Indexed: 06/13/2023] Open
Abstract
Non-typeable Haemophilus influenzae (NTHi) is a Gram-negative human pathogen that causes a wide range of airway diseases. NTHi has a plethora of mechanisms to colonize while evading the host immune system for the establishment of infection. We previously showed that the outer membrane protein P5 contributes to bacterial serum resistance by the recruitment of complement regulators. Here, we report a novel role of P5 in maintaining bacterial outer membrane (OM) integrity and protein composition important for NTHi-host interactions. In silico analysis revealed a peptidoglycan-binding motif at the periplasmic C-terminal domain (CTD) of P5. In a peptidoglycan-binding assay, the CTD of P5 (P5CTD) formed a complex with peptidoglycan. Protein profiling analysis revealed that deletion of CTD or the entire P5 changed the membrane protein composition of the strains NTHi 3655Δp5CTD and NTHi 3655Δp5, respectively. Relative abundance of several membrane-associated virulence factors that are crucial for adherence to the airway mucosa, and serum resistance were altered. This was also supported by similar attenuated pathogenic phenotypes observed in both NTHi 3655Δp5 CTD and NTHi 3655Δp5. We found (i) a decreased adherence to airway epithelial cells and fibronectin, (ii) increased complement-mediated killing, and (iii) increased sensitivity to the β-lactam antibiotics in both mutants compared to NTHi 3655 wild-type. These mutants were also more sensitive to lysis at hyperosmotic conditions and hypervesiculated compared to the parent wild-type bacteria. In conclusion, our results suggest that P5 is important for bacterial OM stability, which ultimately affects the membrane proteome and NTHi pathogenesis.
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Affiliation(s)
- Yu-Ching Su
- Department of Translational Medicine, Clinical Microbiology, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Mahendar Kadari
- Department of Translational Medicine, Clinical Microbiology, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Megan L. Straw
- Department of Translational Medicine, Clinical Microbiology, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Martina Janoušková
- Department of Translational Medicine, Clinical Microbiology, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Sandra Jonsson
- Department of Translational Medicine, Clinical Microbiology, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Oskar Thofte
- Department of Translational Medicine, Clinical Microbiology, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Farshid Jalalvand
- Department of Translational Medicine, Clinical Microbiology, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Erika Matuschek
- European Committee on Antimicrobial Susceptibility Testing (EUCAST) Development Laboratory, c/o Clinical Microbiology, Central Hospital, Växjö, Sweden
| | - Linda Sandblad
- Department of Chemistry and The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Ákos Végvári
- Division of Chemistry I, Department of Medical Biochemistry & Biophysics (MBB), Proteomics Biomedicum, Karolinska Institute, Stockholm, Sweden
| | - Roman A. Zubarev
- Division of Chemistry I, Department of Medical Biochemistry & Biophysics (MBB), Proteomics Biomedicum, Karolinska Institute, Stockholm, Sweden
| | - Kristian Riesbeck
- Department of Translational Medicine, Clinical Microbiology, Faculty of Medicine, Lund University, Malmö, Sweden
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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: 3] [Impact Index Per Article: 1.0] [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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Thofte O, Bettoni S, Su YC, Thegerström J, Jonsson S, Mattsson E, Sandblad L, Martí S, Garmendia J, Blom AM, Riesbeck K. Nontypeable Haemophilus influenzae P5 Binds Human C4b-Binding Protein, Promoting Serum Resistance. THE JOURNAL OF IMMUNOLOGY 2021; 207:1566-1577. [PMID: 34433620 PMCID: PMC8428749 DOI: 10.4049/jimmunol.2100105] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 07/14/2021] [Indexed: 01/03/2023]
Abstract
Exposure of P5 at the surface of NTHi positively correlates with C4BP binding. C4BP bound to the bacterial surface retains its complement inhibitory capacity. C4BP binding to P5 is important for NTHi serum resistance.
Nontypeable Haemophilus influenzae (NTHi) is a Gram-negative human pathogen that causes infections mainly in the upper and lower respiratory tract. The bacterium is associated with bronchitis and exacerbations in patients suffering from chronic obstructive pulmonary disease and frequently causes acute otitis media in preschool children. We have previously demonstrated that the binding of C4b binding protein (C4BP) is important for NTHi complement evasion. In this study, we identified outer membrane protein 5 (P5) of NTHi as a novel ligand of C4BP. Importantly, we observed significantly lower C4BP binding and decreased serum resistance in P5-deficient NTHi mutants. Surface expression of recombinant P5 on Escherichia coli conferred C4BP binding and consequently increased serum resistance. Moreover, P5 expression was positively correlated with C4BP binding in a series of clinical isolates. We revealed higher levels of P5 surface expression and consequently more C4BP binding in isolates from the lower respiratory tract of chronic obstructive pulmonary disease patients and tonsil specimens compared with isolates from the upper respiratory tract and the bloodstream (invasive strains). Our results highlight P5 as an important protein for protecting NTHi against complement-mediated killing.
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Affiliation(s)
- Oskar Thofte
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Serena Bettoni
- Protein Chemistry, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Yu-Ching Su
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - John Thegerström
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Sandra Jonsson
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Emma Mattsson
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Linda Sandblad
- Department of Molecular Biology, Umeå University, Umea, Sweden
| | - Sara Martí
- Microbiology Department, Research Network for Respiratory Diseases, Bellvitge Institute for Biomedical Research, Bellvitge University Hospital, Barcelona, Spain; and
| | - Junkal Garmendia
- Instituto de Agrobiotecnología, Consejo Superior de Investigaciones Científicas-Gobierno de Navarra, Mutilva, Spain
| | - Anna M Blom
- Protein Chemistry, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Kristian Riesbeck
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden;
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6
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Yu Y, Wang J, Han R, Wang L, Zhang L, Zhang AY, Xin J, Li S, Zeng Y, Shao G, Feng Z, Xiong Q. Mycoplasma hyopneumoniae evades complement activation by binding to factor H via elongation factor thermo unstable (EF-Tu). Virulence 2021; 11:1059-1074. [PMID: 32815770 PMCID: PMC7549910 DOI: 10.1080/21505594.2020.1806664] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Mycoplasmas persist in the host for a long time, suggesting that they possess mechanisms for immune evasion. Factor H is a negative regulator of the complement system, which binds to host cells to avoid unexpected complement activation. In this study, we revealed that many mycoplasmas, such as Mycoplasma hyopneumoniae, Mycoplasma hyorhinis, Mycoplasma hyosynoviae, Mycoplasma gallisepticum, Mycoplasma pneumoniae, Mycoplasma genitalium, Mycoplasma flocculare, and Mycoplasma bovis could hijack factor H such that they present themselves as a host tissue and thus escape from complement attack. Furthermore, the mechanism of recruiting factor H was identified in M. hyopneumoniae. M. hyopneumoniae binds factor H via factor H binding proteins, such as elongation factor thermo unstable (EF-Tu), P146, pyruvate dehydrogenase (acetyl-transferring) E1 component subunit alpha (PdhA), P46, Pyruvate dehydrogenase E1 component subunit beta (PdhB), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and three different hypothetical proteins. The binding of factor H by EF-Tu further contributes to decreased C3 deposition on the M. hyopneumoniae surface and ultimately blocks further complement activation. In fact, binding of factor H occurs in a multifactorial manner; factor H is not only exploited by M. hyopneumoniae via its regulator activity to help mycoplasmas escape from complement killing, but also increases M. hyopneumoniae adhesion to swine tracheal epithelial cells, partially through EF-Tu. Meanwhile, the high sequence identity among EF-Tu proteins in the above-mentioned mycoplasmas implied the universality of the mechanism. This is the first report that mycoplasmas can escape complement killing by binding to factor H.
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Affiliation(s)
- Yanfei Yu
- Key Laboratory of Veterinary Biological Engineering and Technology of Ministry of Agriculture, National Center for Engineering Research of Veterinary Bioproducts, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences , Nanjing, China.,School of Food and Biological Engineering, Jiangsu University , Zhenjiang, China
| | - Jia Wang
- Key Laboratory of Veterinary Biological Engineering and Technology of Ministry of Agriculture, National Center for Engineering Research of Veterinary Bioproducts, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences , Nanjing, China.,College of Agriculture, Engineering & Science, University of KwaZulu-Natal , Durban, South Africa
| | - Rui Han
- Key Laboratory of Veterinary Biological Engineering and Technology of Ministry of Agriculture, National Center for Engineering Research of Veterinary Bioproducts, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences , Nanjing, China.,High Magnetic Field Laboratory, Chinese Academy of Sciences , Hefei, China
| | - Li Wang
- Key Laboratory of Veterinary Biological Engineering and Technology of Ministry of Agriculture, National Center for Engineering Research of Veterinary Bioproducts, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences , Nanjing, China
| | - Lei Zhang
- Key Laboratory of Veterinary Biological Engineering and Technology of Ministry of Agriculture, National Center for Engineering Research of Veterinary Bioproducts, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences , Nanjing, China
| | - Amy Yimin Zhang
- College of Veterinary Medicine, Cornell University , Cornell, NY, USA
| | - Jiuqing Xin
- Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences , Harbin, China
| | - Shaoli Li
- Department of Bacteriology, Capital Institute of Pediatrics , Beijing, China
| | - Yanhua Zeng
- Institute of Pathogenic Biology, Hengyang Medical College, University of South China , Hengyang, China
| | - Guoqing Shao
- Key Laboratory of Veterinary Biological Engineering and Technology of Ministry of Agriculture, National Center for Engineering Research of Veterinary Bioproducts, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences , Nanjing, China.,School of Food and Biological Engineering, Jiangsu University , Zhenjiang, China
| | - Zhixin Feng
- Key Laboratory of Veterinary Biological Engineering and Technology of Ministry of Agriculture, National Center for Engineering Research of Veterinary Bioproducts, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences , Nanjing, China
| | - Qiyan Xiong
- Key Laboratory of Veterinary Biological Engineering and Technology of Ministry of Agriculture, National Center for Engineering Research of Veterinary Bioproducts, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences , Nanjing, China.,Institute of Life Sciences, Jiangsu University , Zhenjiang, China
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7
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Unraveling Haemophilus influenzae virulence mechanisms enable discovery of new targets for antimicrobials and vaccines. Curr Opin Infect Dis 2021; 33:231-237. [PMID: 32304471 DOI: 10.1097/qco.0000000000000645] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PURPOSE OF REVIEW The human upper respiratory tract is colonized with a variety of bacterial microorganisms including Haemophilus influenzae. The species H. influenzae consists of typeable and nontypeable H. influenzae (NTHi) variants. Typeable H. influenzae are subdivided into types a through f, based on the polysaccharide capsule, whereas the NTHi strains do not express a polysaccharide capsule. In this review, we highlight the current advances in the field of H. influenzae, with the focus on bacterial virulence mechanisms that facilitate bacterial colonization and disease, particularly for NTHi. RECENT FINDINGS In the past decade, it has become apparent that NTHi has the ability to cause invasive infections. Recently, a number of adhesins have been shown to be crucial for bacterial colonization and invasion and these proteins were investigated as vaccine antigens. Although NTHi lacks a polysaccharide capsule, it expresses lipooligosaccharide that contribute to adhesion and evasion of complement-mediated killing, both contributing to bacterial virulence, which could potentially be targeted by novel antimicrobial drugs or vaccines. SUMMARY The unraveling of H. influenzae virulence mechanisms resulted in the identification of promising targets for novel antimicrobials and vaccine antigens aiming to prevent or treat both typeable and nontypeable H. influenzae infections.
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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: 42] [Impact Index Per Article: 14.0] [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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Exploring the Impact of Ketodeoxynonulosonic Acid in Host-Pathogen Interactions Using Uptake and Surface Display by Nontypeable Haemophilus influenzae. mBio 2021; 12:mBio.03226-20. [PMID: 33468699 PMCID: PMC7845648 DOI: 10.1128/mbio.03226-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
All cells in vertebrates are coated with a dense array of glycans often capped with sugars called sialic acids. Sialic acids have many functions, including serving as a signal for recognition of “self” cells by the immune system, thereby guiding an appropriate immune response against foreign “nonself” and/or damaged cells. Surface expression of the common vertebrate sialic acid (Sia) N-acetylneuraminic acid (Neu5Ac) by commensal and pathogenic microbes appears structurally to represent “molecular mimicry” of host sialoglycans, facilitating multiple mechanisms of host immune evasion. In contrast, ketodeoxynonulosonic acid (Kdn) is a more ancestral Sia also present in prokaryotic glycoconjugates that are structurally quite distinct from vertebrate sialoglycans. We detected human antibodies against Kdn-terminated glycans, and sialoglycan microarray studies found these anti-Kdn antibodies to be directed against Kdn-sialoglycans structurally similar to those on human cell surface Neu5Ac-sialoglycans. Anti-Kdn-glycan antibodies appear during infancy in a pattern similar to those generated following incorporation of the nonhuman Sia N-glycolylneuraminic acid (Neu5Gc) onto the surface of nontypeable Haemophilus influenzae (NTHi), a human commensal and opportunistic pathogen. NTHi grown in the presence of free Kdn took up and incorporated the Sia into its lipooligosaccharide (LOS). Surface display of the Kdn within NTHi LOS blunted several virulence attributes of the pathogen, including Neu5Ac-mediated resistance to complement and whole blood killing, complement C3 deposition, IgM binding, and engagement of Siglec-9. Upper airway administration of Kdn reduced NTHi infection in human-like Cmah null (Neu5Gc-deficient) mice that express a Neu5Ac-rich sialome. We propose a mechanism for the induction of anti-Kdn antibodies in humans, suggesting that Kdn could be a natural and/or therapeutic “Trojan horse” that impairs colonization and virulence phenotypes of free Neu5Ac-assimilating human pathogens.
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10
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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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11
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de Boer ECW, van Mourik AG, Jongerius I. Therapeutic Lessons to be Learned From the Role of Complement Regulators as Double-Edged Sword in Health and Disease. Front Immunol 2020; 11:578069. [PMID: 33362763 PMCID: PMC7758290 DOI: 10.3389/fimmu.2020.578069] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/12/2020] [Indexed: 12/22/2022] Open
Abstract
The complement system is an important part of the innate immune system, providing a strong defense against pathogens and removing apoptotic cells and immune complexes. Due to its strength, it is important that healthy human cells are protected against damage induced by the complement system. To be protected from complement, each cell type relies on a specific combination of both soluble and membrane-bound regulators. Their importance is indicated by the amount of pathologies associated with abnormalities in these complement regulators. Here, we will discuss the current knowledge on complement regulatory protein polymorphisms and expression levels together with their link to disease. These diseases often result in red blood cell destruction or occur in the eye, kidney or brain, which are tissues known for aberrant complement activity or regulation. In addition, complement regulators have also been associated with different types of cancer, although their mechanisms here have not been elucidated yet. In most of these pathologies, treatments are limited and do not prevent the complement system from attacking host cells, but rather fight the consequences of the complement-mediated damage, using for example blood transfusions in anemic patients. Currently only few drugs targeting the complement system are used in the clinic. With further demand for therapeutics rising linked to the wide range of complement-mediated disease we should broaden our horizon towards treatments that can actually protect the host cells against complement. Here, we will discuss the latest insights on how complement regulators can benefit therapeutics. Such therapeutics are currently being developed extensively, and can be categorized into full-length complement regulators, engineered complement system regulators and antibodies targeting complement regulators. In conclusion, this review provides an overview of the complement regulatory proteins and their links to disease, together with their potential in the development of novel therapeutics.
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Affiliation(s)
- Esther C W de Boer
- Sanquin Research, Department of Immunopathology, and Landsteiner Laboratory, Amsterdam University Medical Centre, Amsterdam Infection and Immunity Institute, Amsterdam, Netherlands.,Department of Pediatric Immunology, Rheumatology, and Infectious Diseases, Emma Children's Hospital, Amsterdam University Medical Centre, Amsterdam, Netherlands
| | - Anouk G van Mourik
- Sanquin Research, Department of Immunopathology, and Landsteiner Laboratory, Amsterdam University Medical Centre, Amsterdam Infection and Immunity Institute, Amsterdam, Netherlands
| | - Ilse Jongerius
- Sanquin Research, Department of Immunopathology, and Landsteiner Laboratory, Amsterdam University Medical Centre, Amsterdam Infection and Immunity Institute, Amsterdam, Netherlands.,Department of Pediatric Immunology, Rheumatology, and Infectious Diseases, Emma Children's Hospital, Amsterdam University Medical Centre, Amsterdam, Netherlands
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12
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Laabei M, Colineau L, Bettoni S, Maziarz K, Ermert D, Riesbeck K, Ram S, Blom AM. Antibacterial Fusion Proteins Enhance Moraxella catarrhalis Killing. Front Immunol 2020; 11:2122. [PMID: 32983170 PMCID: PMC7492680 DOI: 10.3389/fimmu.2020.02122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 08/05/2020] [Indexed: 01/10/2023] Open
Abstract
Moraxella catarrhalis is a human-specific commensal of the respiratory tract and an opportunistic pathogen. It is one of the leading cause of otitis media in children and of acute exacerbations in patients with chronic obstructive pulmonary disease, resulting in significant morbidity and economic burden. Vaccines and new immunotherapeutic strategies to treat this emerging pathogen are needed. Complement is a key component of innate immunity that mediates the detection, response, and subsequent elimination of invading pathogens. Many pathogens including M. catarrhalis have evolved complement evasion mechanisms, which include the binding of human complement inhibitors such as C4b-binding protein (C4BP) and Factor H (FH). Inhibiting C4BP and FH acquisition by M. catarrhalis may provide a novel therapeutic avenue to treat infections. To achieve this, we created two chimeric proteins that combined the Moraxella-binding domains of C4BP and FH fused to human immunoglobulin Fcs: C4BP domains 1 and 2 and FH domains 6 and 7 fused to IgM and IgG Fc, respectively. As expected, FH6-7/IgG displaced FH from the bacterial surface while simultaneously activating complement via Fc-C1q interactions, together increasing pathogen elimination. C4BP1-2/IgM also increased serum killing of the bacteria through enhanced complement deposition, but did not displace C4BP from the surface of M. catarrhalis. These Fc fusion proteins could act as anti-infective immunotherapies. Many microbes bind the complement inhibitors C4BP and FH through the same domains as M. catarrhalis, therefore these Fc fusion proteins may be promising candidates as adjunctive therapy against many different drug-resistant pathogens.
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Affiliation(s)
- Maisem Laabei
- Division of Medical Protein Chemistry, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden.,Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Lucie Colineau
- Division of Medical Protein Chemistry, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Serena Bettoni
- Division of Medical Protein Chemistry, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Karolina Maziarz
- Division of Medical Protein Chemistry, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - David Ermert
- Division of Medical Protein Chemistry, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Kristian Riesbeck
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Sanjay Ram
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA, United States
| | - Anna M Blom
- Division of Medical Protein Chemistry, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
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13
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Complement Evasion Strategies of Human Pathogenic Bacteria. Indian J Microbiol 2020; 60:283-296. [PMID: 32655196 DOI: 10.1007/s12088-020-00872-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 04/07/2020] [Indexed: 12/21/2022] Open
Abstract
Human pathogens need to overcome an elaborate network of host defense mechanisms in order to establish their infection, colonization, proliferation and eventual dissemination. The interaction of pathogens with different effector molecules of the immune system results in their neutralization and elimination from the host. The complement system is one such integral component of innate immunity that is critically involved in the early recognition and elimination of the pathogen. Hence, under this immune pressure, all virulent pathogens capable of inducing active infections have evolved immune evasive strategies that primarily target the complement system, which plays an essential and central role for host defense. Recent reports on several bacterial pathogens have elucidated the molecular mechanisms underlying complement evasion, inhibition of opsonic phagocytosis and cell lysis. This review aims to comprehensively summarize the recent findings on the various strategies adopted by pathogenic bacteria to escape complement-mediated clearance.
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14
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Riesbeck K. Complement evasion by the human respiratory tract pathogens Haemophilus influenzae and Moraxella catarrhalis. FEBS Lett 2020; 594:2586-2597. [PMID: 32053211 DOI: 10.1002/1873-3468.13758] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 01/26/2020] [Accepted: 02/09/2020] [Indexed: 12/14/2022]
Abstract
All infective bacterial species need to conquer the innate immune system in order to colonize and survive in their hosts. The human respiratory pathogens Haemophilus influenzae and Moraxella catarrhalis are no exceptions and have developed sophisticated mechanisms to evade complement-mediated killing. Both bacterial species carry lipooligosaccharides preventing complement attacks and attract and utilize host complement regulators C4b binding protein and factor H to inhibit the classical and alternative pathways of complement activation, respectively. In addition, the regulator of the terminal pathway of complement activation, vitronectin, is hijacked by both bacteria. An array of different outer membrane proteins (OMP) in H. influenzae and M. catarrhalis simultaneously binds complement regulators, but also plasminogen. Several of the bacterial complement-binding proteins are important adhesins and contain highly conserved regions for interactions with the host. Thus, some of the OMP are viable targets for new therapeutics, including vaccines aimed at preventing respiratory tract diseases such as otitis media in children and exacerbations in patients suffering from chronic obstructive pulmonary disease.
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Affiliation(s)
- Kristian Riesbeck
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
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15
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Galeas-Pena M, McLaughlin N, Pociask D. The role of the innate immune system on pulmonary infections. Biol Chem 2019; 400:443-456. [PMID: 29604208 DOI: 10.1515/hsz-2018-0304] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 09/19/2018] [Indexed: 12/15/2022]
Abstract
Inhalation is required for respiration and life in all vertebrates. This process is not without risk, as it potentially exposes the host to environmental pathogens with every breath. This makes the upper respiratory tract one of the most common routes of infection and one of the leading causes of morbidity and mortality in the world. To combat this, the lung relies on the innate immune defenses. In contrast to the adaptive immune system, the innate immune system does not require sensitization, previous exposure or priming to attack foreign particles. In the lung, the innate immune response starts with the epithelial barrier and mucus production and is reinforced by phagocytic cells and T cells. These cells are vital for the production of cytokines, chemokines and anti-microbial peptides that are critical for clearance of infectious agents. In this review, we discuss all aspects of the innate immune response, with a special emphasis on ways to target aspects of the immune response to combat antibiotic resistant bacteria.
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Affiliation(s)
- Michelle Galeas-Pena
- Department of Pulmonary Critical Care and Environmental Medicine, Tulane University School of Medicine, 333 S. Liberty St., New Orleans, LA 70112, USA
| | - Nathaniel McLaughlin
- Department of Pulmonary Critical Care and Environmental Medicine, Tulane University School of Medicine, 333 S. Liberty St., New Orleans, LA 70112, USA
| | - Derek Pociask
- Department of Pulmonary Critical Care and Environmental Medicine, Tulane University School of Medicine, 333 S. Liberty St., New Orleans, LA 70112, USA
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16
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Bettoni S, Shaughnessy J, Maziarz K, Ermert D, Gulati S, Zheng B, Mörgelin M, Jacobsson S, Riesbeck K, Unemo M, Ram S, Blom AM. C4BP-IgM protein as a therapeutic approach to treat Neisseria gonorrhoeae infections. JCI Insight 2019; 4:131886. [PMID: 31661468 PMCID: PMC6962029 DOI: 10.1172/jci.insight.131886] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 10/23/2019] [Indexed: 12/21/2022] Open
Abstract
Gonorrhea is a sexually transmitted infection with 87 million new cases per year globally. Increasing antibiotic resistance has severely limited treatment options. A mechanism that Neisseria gonorrhoeae uses to evade complement attack is binding of the complement inhibitor C4b-binding protein (C4BP). We screened 107 porin B1a (PorB1a) and 83 PorB1b clinical isolates randomly selected from a Swedish strain collection over the last 10 years and noted that 96/107 (89.7%) PorB1a and 16/83 (19.3%) PorB1b bound C4BP; C4BP binding substantially correlated with the ability to evade complement-dependent killing (r = 0.78). We designed 2 chimeric proteins that fused C4BP domains to the backbone of IgG or IgM (C4BP-IgG; C4BP-IgM) with the aim of enhancing complement activation and killing of gonococci. Both proteins bound gonococci (KD C4BP-IgM = 2.4 nM; KD C4BP-IgG 980.7 nM), but only hexameric C4BP-IgM efficiently outcompeted heptameric C4BP from the bacterial surface, resulting in enhanced complement deposition and bacterial killing. Furthermore, C4BP-IgM substantially attenuated the duration and burden of colonization of 2 C4BP-binding gonococcal isolates but not a non-C4BP-binding strain in a mouse vaginal colonization model using human factor H/C4BP-transgenic mice. Our preclinical data present C4BP-IgM as an adjunct to conventional antimicrobials for the treatment of gonorrhea.
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Affiliation(s)
- Serena Bettoni
- Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Jutamas Shaughnessy
- Department of Medicine, Division of Infectious Diseases, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Karolina Maziarz
- Department of Translational Medicine, Lund University, Malmö, Sweden
| | - David Ermert
- Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Sunita Gulati
- Department of Medicine, Division of Infectious Diseases, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Bo Zheng
- Department of Medicine, Division of Infectious Diseases, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | | | - Susanne Jacobsson
- World Health Organization (WHO) Collaborating Centre for Gonorrhoea and other STIs, Department of Laboratory Medicine, Örebro University, Örebro, Sweden
| | - Kristian Riesbeck
- Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Magnus Unemo
- World Health Organization (WHO) Collaborating Centre for Gonorrhoea and other STIs, Department of Laboratory Medicine, Örebro University, Örebro, Sweden
| | - Sanjay Ram
- Department of Medicine, Division of Infectious Diseases, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Anna M. Blom
- Department of Translational Medicine, Lund University, Malmö, Sweden
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17
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New therapeutic targets for the prevention of infectious acute exacerbations of COPD: role of epithelial adhesion molecules and inflammatory pathways. Clin Sci (Lond) 2019; 133:1663-1703. [PMID: 31346069 DOI: 10.1042/cs20181009] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 06/27/2019] [Accepted: 06/28/2019] [Indexed: 12/15/2022]
Abstract
Chronic respiratory diseases are among the leading causes of mortality worldwide, with the major contributor, chronic obstructive pulmonary disease (COPD) accounting for approximately 3 million deaths annually. Frequent acute exacerbations (AEs) of COPD (AECOPD) drive clinical and functional decline in COPD and are associated with accelerated loss of lung function, increased mortality, decreased health-related quality of life and significant economic costs. Infections with a small subgroup of pathogens precipitate the majority of AEs and consequently constitute a significant comorbidity in COPD. However, current pharmacological interventions are ineffective in preventing infectious exacerbations and their treatment is compromised by the rapid development of antibiotic resistance. Thus, alternative preventative therapies need to be considered. Pathogen adherence to the pulmonary epithelium through host receptors is the prerequisite step for invasion and subsequent infection of surrounding structures. Thus, disruption of bacterial-host cell interactions with receptor antagonists or modulation of the ensuing inflammatory profile present attractive avenues for therapeutic development. This review explores key mediators of pathogen-host interactions that may offer new therapeutic targets with the potential to prevent viral/bacterial-mediated AECOPD. There are several conceptual and methodological hurdles hampering the development of new therapies that require further research and resolution.
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18
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Kenno S, Speth C, Rambach G, Binder U, Chatterjee S, Caramalho R, Haas H, Lass-Flörl C, Shaughnessy J, Ram S, Gow NAR, Orth-Höller D, Würzner R. Candida albicans Factor H Binding Molecule Hgt1p - A Low Glucose-Induced Transmembrane Protein Is Trafficked to the Cell Wall and Impairs Phagocytosis and Killing by Human Neutrophils. Front Microbiol 2019; 9:3319. [PMID: 30697200 PMCID: PMC6340940 DOI: 10.3389/fmicb.2018.03319] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 12/20/2018] [Indexed: 12/15/2022] Open
Abstract
Complement is a tightly controlled arm of the innate immune system, facilitating phagocytosis and killing of invading pathogens. Factor H (FH) is the main fluid-phase inhibitor of the alternative pathway. Many pathogens can hijack FH from the host and protect themselves from complement-dependent killing. Candida albicans is a clinically important opportunistic yeast, expressing different FH binding molecules on its cell surface, which allow complement evasion. One such FH binding molecule is the transmembrane protein "High affinity glucose transporter 1" (Hgt1p), involved in glucose metabolism. This study demonstrated that Hgt1p transcription and expression is induced and highest at the low, but physiological glucose concentration of 0.1%. Thus, this concentration was used throughout the study. We also demonstrated the transport of Hgt1p to the fungal cell wall surface by vesicle trafficking and its release by exosomes containing Hgt1p integrated in the vesicular membrane. We corroborated Hgt1p as FH binding molecule. A polyclonal anti-Hgt1p antibody was created which interfered with the binding of FH, present in normal human serum to the fungal cell wall. A chimeric molecule consisting of FH domains 6 and 7 fused to human IgG1 Fc (FH6.7/Fc) even more comprehensively blocked FH binding, likely because FH6.7/Fc diverted FH away from fungal FH ligands other than Hgt1p. Reduced FH binding to the yeast was associated with a concomitant increase in C3b/iC3b deposition and resulted in significantly increased in vitro phagocytosis and killing by human neutrophils. In conclusion, Hgt1p also exhibits non-canonical functions such as binding FH after its export to the cell wall. Blocking Hgt1p-FH interactions may represent a tool to enhance complement activation on the fungal surface to promote phagocytosis and killing of C. albicans.
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Affiliation(s)
- Samyr Kenno
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Cornelia Speth
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Günter Rambach
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Ulrike Binder
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Sneha Chatterjee
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Rita Caramalho
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Hubertus Haas
- Division of Molecular Biology, Medical University of Innsbruck, Innsbruck, Austria
| | - Cornelia Lass-Flörl
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA, United States
| | - Sanjay Ram
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA, United States
| | - Neil A R Gow
- School of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Dorothea Orth-Höller
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Reinhard Würzner
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
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19
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Shaughnessy J, Lewis LA, Zheng B, Carr C, Bass I, Gulati S, DeOliveira RB, Gose S, Reed GW, Botto M, Rice PA, Ram S. Human Factor H Domains 6 and 7 Fused to IgG1 Fc Are Immunotherapeutic against Neisseria gonorrhoeae. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2018; 201:2700-2709. [PMID: 30266769 PMCID: PMC6200640 DOI: 10.4049/jimmunol.1701666] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 08/27/2018] [Indexed: 01/15/2023]
Abstract
Novel therapeutics against multidrug-resistant Neisseria gonorrhoeae are urgently needed. Gonococcal lipooligosaccharide often expresses lacto-N-neotetraose (LNnT), which becomes sialylated in vivo, enhancing factor H (FH) binding and contributing to the organism's ability to resist killing by complement. We previously showed that FH domains 18-20 (with a D-to-G mutation at position 1119 in domain 19) fused to Fc (FHD1119G/Fc) displayed complement-dependent bactericidal activity in vitro and attenuated gonococcal vaginal colonization of mice. Gonococcal lipooligosaccharide phase variation can result in loss of LNnT expression. Loss of sialylated LNnT, although associated with a considerable fitness cost, could decrease efficacy of FHD1119G/Fc. Similar to N. meningitidis, gonococci also bind FH domains 6 and 7 through Neisserial surface protein A (NspA). In this study, we show that a fusion protein comprising FH domains 6 and 7 fused to human IgG1 Fc (FH6,7/Fc) bound to 15 wild-type antimicrobial resistant isolates of N. gonorrhoeae and to each of six lgtA gonococcal deletion mutants. FH6,7/Fc mediated complement-dependent killing of 8 of the 15 wild-type gonococcal isolates and effectively reduced the duration and burden of vaginal colonization of three gonococcal strains tested in wild-type mice, including two strains that resisted complement-dependent killing but on which FH6,7/Fc enhanced C3 deposition. FH/Fc lost efficacy when Fc was mutated to abrogate C1q binding and in C1q-/- mice, highlighting the requirement of the classical pathway for its activity. Targeting gonococci with FH6,7/Fc provides an additional immunotherapeutic approach against multidrug-resistant gonorrhea.
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Affiliation(s)
- Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Lisa A Lewis
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Bo Zheng
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Caleb Carr
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Isaac Bass
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Sunita Gulati
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Rosane B DeOliveira
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Severin Gose
- San Francisco Department of Public Health, San Francisco, CA 94102; and
| | - George W Reed
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Marina Botto
- Faculty of Medicine, Imperial College London, London SW7 2AZ, United Kingdom
| | - Peter A Rice
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Sanjay Ram
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605;
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20
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Pastor Y, Camacho AI, Zúñiga-Ripa A, Merchán A, Rosas P, Irache JM, Gamazo C. Towards a subunit vaccine from a Shigella flexneri ΔtolR mutant. Vaccine 2018; 36:7509-7519. [PMID: 30420041 DOI: 10.1016/j.vaccine.2018.10.066] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 09/12/2018] [Accepted: 10/17/2018] [Indexed: 11/24/2022]
Abstract
Disruption of one or more components of the Tol-Pal system, involved in maintaining the integrity of the outer membrane of Gram-negative bacteria, has been proposed as a method to increase the yield obtained from natural production of outer membrane vesicles (OMV). We present a new OMV-based product, obtained from genetically modified Shigella flexneri 2a with a non-polar deletion in tolR and heat-inactivated (HT-ΔtolR). The S. flexneri ΔtolR strain lead to a higher release of vesicles, more than 8-times when compared to the yield obtained from chemically inactivated wild type strain. S. flexneri mutant strain appeared to be more sensitive to different chemical compounds, including antibiotics, bile salts or human complement and it was also less virulent in both in vitro and in vivo assays. The mutation produced some changes in the LPS O-chain and protein expression. S. flexneri ΔtolR was enriched in long and very long LPS O-chain and expressed a different pattern of surface proteins or lipoproteins. In vitro toxicity and activation properties were determined in Raw 267.4 macrophage cell line. HT-ΔtolR antigenic complex was non-cytotoxic and activation markers, such as MHC-II or CD40, were highly expressed during incubation with this product. Finally, preliminary studies on the antibody response elicited by HT-ΔtolR demonstrated a robust and diverse response in mice. Considering these promising results, HT-ΔtolR antigenic extract appears as a new potential vaccine candidate to face shigellosis.
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Affiliation(s)
- Yadira Pastor
- Department of Microbiology, Institute of Tropical Health - University of Navarra, 31008 Pamplona, Spain
| | - Ana Isabel Camacho
- Department of Microbiology, Institute of Tropical Health - University of Navarra, 31008 Pamplona, Spain
| | - Amaia Zúñiga-Ripa
- Department of Microbiology, Institute of Tropical Health - University of Navarra, 31008 Pamplona, Spain
| | - Aritz Merchán
- Department of Microbiology, Institute of Tropical Health - University of Navarra, 31008 Pamplona, Spain
| | - Pablo Rosas
- Department of Microbiology, Institute of Tropical Health - University of Navarra, 31008 Pamplona, Spain
| | - Juan M Irache
- Department of Pharmaceutical Technology, Institute of Tropical Health - University of Navarra, 31008 Pamplona, Spain
| | - Carlos Gamazo
- Department of Microbiology, Institute of Tropical Health - University of Navarra, 31008 Pamplona, Spain.
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21
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Laabei M, Ermert D. Catch Me if You Can: Streptococcus pyogenes Complement Evasion Strategies. J Innate Immun 2018; 11:3-12. [PMID: 30269134 DOI: 10.1159/000492944] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 08/16/2018] [Indexed: 12/27/2022] Open
Abstract
The human host has evolved elaborate protection mechanisms to prevent infection from the billions of microorganisms to which it host is exposed and is home. One of these systems, complement, is an evolutionary ancient arm of innate immunity essential for combatting bacterial infection. Complement permits the efficient labelling of bacteria with opsonins, supports phagocytosis, and facilitates phagocyte recruitment to the site of infection through the production of chemoattractants. However, it is by no means perfect, and certain organisms engage in an evolutionary arms race with the host where complement has become a major target to promote immune evasion. Streptococcus pyogenes is a major human pathogen that causes significant morbidity and mortality globally. S. pyogenes is also a member of an elite group of bacterial pathogens possessing a sophisticated arsenal of virulence determinants capable of interfering with complement. In this review, we focus on these complement evasins, their mechanism of action, and their importance in disease progression. Finally, we highlight new therapeutic options for fighting S. pyogenes, by interfering with one of its main mechanisms of complement evasion.
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22
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Recognition of conserved antigens by Th17 cells provides broad protection against pulmonary Haemophilus influenzae infection. Proc Natl Acad Sci U S A 2018; 115:E7149-E7157. [PMID: 29987031 DOI: 10.1073/pnas.1802261115] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is a major cause of community acquired pneumonia and exacerbation of chronic obstructive pulmonary disease. A current effort in NTHi vaccine development has focused on generating humoral responses and has been greatly impeded by antigenic variation among the numerous circulating NTHi strains. In this study, we showed that pulmonary immunization of mice with killed NTHi generated broad protection against lung infection by different strains. While passive transfer of immune antibodies protected only against the homologous strain, transfer of immune T cells conferred protection against both homologous and heterologous strains. Further characterization revealed a strong Th17 response that was cross-reactive with different NTHi strains. Responding Th17 cells recognized both cytosolic and membrane-associated antigens, while immune antibodies preferentially responded to surface antigens and were highly strain specific. We further identified several conserved proteins recognized by lung Th17 cells during NTHi infection. Two proteins yielding the strongest responses were tested as vaccine candidates by immunization of mice with purified proteins plus an adjuvant. Immunization induced antigen-specific Th17 cells that recognized different strains and, upon adoptive transfer, conferred protection. Furthermore, immunized mice were protected against challenge with not only NTHi strains but also a fully virulent, encapsulated strain. Together, these results show that the immune mechanism of cross-protection against pneumonia involves Th17 cells, which respond to a broad spectrum of antigens, including those that are highly conserved among NTHi strains. These mechanistic insights suggest that inclusion of Th17 antigens in subunit vaccines offers the advantage of inducing broad protection and complements the current antibody-based approaches.
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Jalalvand F, Riesbeck K. Update on non-typeable Haemophilus influenzae-mediated disease and vaccine development. Expert Rev Vaccines 2018; 17:503-512. [DOI: 10.1080/14760584.2018.1484286] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Farshid Jalalvand
- Centre for Bacterial Stress Response and Persistence, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Kristian Riesbeck
- Clinical Microbiology, Department of Translational Medicine, Lund University, Malmö, Sweden
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Blom AM, Magda M, Kohl L, Shaughnessy J, Lambris JD, Ram S, Ermert D. Factor H-IgG Chimeric Proteins as a Therapeutic Approach against the Gram-Positive Bacterial Pathogen Streptococcus pyogenes. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2017; 199:3828-3839. [PMID: 29084837 PMCID: PMC5698128 DOI: 10.4049/jimmunol.1700426] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 09/30/2017] [Indexed: 11/19/2022]
Abstract
Bacteria can cause life-threatening infections, such as pneumonia, meningitis, or sepsis. Antibiotic therapy is a mainstay of treatment, although antimicrobial resistance has drastically increased over the years. Unfortunately, safe and effective vaccines against most pathogens have not yet been approved, and thus developing alternative treatments is important. We analyzed the efficiency of factor H (FH)6-7/Fc, a novel antibacterial immunotherapeutic protein against the Gram-positive bacterium Streptococcus pyogenes This protein is composed of two domains of complement inhibitor human FH (FH complement control protein modules 6 and 7) that bind to S. pyogenes, linked to the Fc region of IgG (FH6-7/Fc). FH6-7/Fc has previously been shown to enhance complement-dependent killing of, and facilitate bacterial clearance in, animal models of the Gram-negative pathogens Haemophilus influenzae and Neisseria meningitidis We hypothesized that activation of complement by FH6-7/Fc on the surface of Gram-positive bacteria such as S. pyogenes will enable professional phagocytes to eliminate the pathogen. We found that FH6-7/Fc alleviated S. pyogenes-induced sepsis in a transgenic mouse model expressing human FH (S. pyogenes binds FH in a human-specific manner). Furthermore, FH6-7/Fc, which binds to protein H and selected M proteins, displaced FH from the bacterial surface, enhanced alternative pathway activation, and reduced bacterial blood burden by opsonophagocytosis in a C3-dependent manner in an ex vivo human whole-blood model. In conclusion, FH-Fc chimeric proteins could serve as adjunctive treatments against multidrug-resistant bacterial infections.
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Affiliation(s)
- Anna M Blom
- Department of Translational Medicine, Medical Protein Chemistry, Lund University, Skåne County Council, Malmö 20502, Sweden
| | - Michal Magda
- Department of Translational Medicine, Medical Protein Chemistry, Lund University, Skåne County Council, Malmö 20502, Sweden
| | - Lisa Kohl
- Department of Translational Medicine, Medical Protein Chemistry, Lund University, Skåne County Council, Malmö 20502, Sweden
| | - Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605; and
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Sanjay Ram
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605; and
| | - David Ermert
- Department of Translational Medicine, Medical Protein Chemistry, Lund University, Skåne County Council, Malmö 20502, Sweden;
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605; and
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25
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Ram S, Shaughnessy J, DeOliveira RB, Lewis LA, Gulati S, Rice PA. Utilizing complement evasion strategies to design complement-based antibacterial immunotherapeutics: Lessons from the pathogenic Neisseriae. Immunobiology 2016; 221:1110-23. [PMID: 27297292 DOI: 10.1016/j.imbio.2016.05.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 05/27/2016] [Indexed: 12/30/2022]
Abstract
Novel therapies are urgently needed to combat the global threat of multidrug-resistant pathogens. Complement forms an important arm of innate defenses against infections. In physiological conditions, complement activation is tightly controlled by soluble and membrane-associated complement inhibitors, but must be selectively activated on invading pathogens to facilitate microbial clearance. Many pathogens, including Neisseria gonorrhoeae and N. meningitidis, express glycans, including N-acetylneuraminic acid (Neu5Ac), that mimic host structures to evade host immunity. Neu5Ac is a negatively charged 9-cabon sugar that inhibits complement, in part by enhancing binding of the complement inhibitor factor H (FH) through C-terminal domains (19 and 20) on FH. Other microbes also bind FH, in most instances through FH domains 6 and 7 or 18-20. Here we describe two strategies to target complement activation on Neisseriae. First, microbial binding domains of FH were fused to IgG Fc to create FH18-20/Fc (binds gonococci) and FH6,7/Fc (binds meningococci). A point mutation in FH domain 19 eliminated hemolysis caused by unmodified FH18-20, but retained binding to gonococci. FH18-20/Fc and FH6,7/Fc mediated complement-dependent killing in vitro and showed efficacy in animal models of gonorrhea and meningococcal bacteremia, respectively. The second strategy utilized CMP-nonulosonate (CMP-NulO) analogs of sialic acid that were incorporated into LOS and prevented complement inhibition by physiologic CMP-Neu5Ac and resulted in attenuated gonococcal infection in mice. While studies to establish the safety of these agents are needed, enhancing complement activation on microbes may represent a promising strategy to treat antimicrobial resistant organisms.
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Affiliation(s)
- Sanjay Ram
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
| | - Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Rosane B DeOliveira
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Lisa A Lewis
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Sunita Gulati
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Peter A Rice
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
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