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Mathew BJ, Gupta P, Naaz T, Rai R, Gupta S, Gupta S, Chaurasiya SK, Purwar S, Biswas D, Vyas AK, Singh AK. Role of Streptococcus pneumoniae extracellular glycosidases in immune evasion. Front Cell Infect Microbiol 2023; 13:1109449. [PMID: 36816580 PMCID: PMC9937060 DOI: 10.3389/fcimb.2023.1109449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Accepted: 01/16/2023] [Indexed: 02/05/2023] Open
Abstract
Streptococcus pneumoniae (pneumococcus) typically colonizes the human upper airway asymptomatically but upon reaching other sites of the host body can cause an array of diseases such as pneumonia, bacteremia, otitis media, and meningitis. Be it colonization or progression to disease state, pneumococcus faces multiple challenges posed by host immunity ranging from complement mediated killing to inflammation driven recruitment of bactericidal cells for the containment of the pathogen. Pneumococcus has evolved several mechanisms to evade the host inflicted immune attack. The major pneumococcal virulence factor, the polysaccharide capsule helps protect the bacteria from complement mediated opsonophagocytic killing. Another important group of pneumococcal proteins which help bacteria to establish and thrive in the host environment is surface associated glycosidases. These enzymes can hydrolyze host glycans on glycoproteins, glycolipids, and glycosaminoglycans and consequently help bacteria acquire carbohydrates for growth. Many of these glycosidases directly or indirectly facilitate bacterial adherence and are known to modulate the function of host defense/immune proteins likely by removing glycans and thereby affecting their stability and/or function. Furthermore, these enzymes are known to contribute the formation of biofilms, the bacterial communities inherently resilient to antimicrobials and host immune attack. In this review, we summarize the role of these enzymes in host immune evasion.
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Affiliation(s)
- Bijina J. Mathew
- Department of Biological Science and Engineering, Maulana Azad National Institute of Technology, Bhopal, India
| | - Priyal Gupta
- Department of Microbiology, All India Institute of Medical Sciences, Bhopal, India
| | - Tabassum Naaz
- Department of Microbiology, All India Institute of Medical Sciences, Bhopal, India
| | - Rupal Rai
- Department of Biological Science and Engineering, Maulana Azad National Institute of Technology, Bhopal, India
| | - Sudheer Gupta
- Research and Development, 3B Blackbio Biotech India Ltd., Bhopal, India
| | - Sudipti Gupta
- Abigail Wexner Research Institute, Nationwide Children’s Hospital, Columbus, OH, United States
| | - Shivendra K. Chaurasiya
- Department of Biological Science and Engineering, Maulana Azad National Institute of Technology, Bhopal, India
| | - Shashank Purwar
- Department of Microbiology, All India Institute of Medical Sciences, Bhopal, India
| | - Debasis Biswas
- Department of Microbiology, All India Institute of Medical Sciences, Bhopal, India
| | - Ashish Kumar Vyas
- John C Martin Centre for Liver Research and Innovation, Liver Foundation Sonarpur, Kolkata, India
| | - Anirudh K. Singh
- School of Sciences, SAM Global University, Raisen, India,*Correspondence: Anirudh K. Singh,
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2
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Gingerich AD, Mousa JJ. Diverse Mechanisms of Protective Anti-Pneumococcal Antibodies. Front Cell Infect Microbiol 2022; 12:824788. [PMID: 35155281 PMCID: PMC8834882 DOI: 10.3389/fcimb.2022.824788] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 01/11/2022] [Indexed: 02/05/2023] Open
Abstract
The gram-positive bacterium Streptococcus pneumoniae is a leading cause of pneumonia, otitis media, septicemia, and meningitis in children and adults. Current prevention and treatment efforts are primarily pneumococcal conjugate vaccines that target the bacterial capsule polysaccharide, as well as antibiotics for pathogen clearance. While these methods have been enormously effective at disease prevention and treatment, there has been an emergence of non-vaccine serotypes, termed serotype replacement, and increasing antibiotic resistance among these serotypes. To combat S. pneumoniae, the immune system must deploy an arsenal of antimicrobial functions. However, S. pneumoniae has evolved a repertoire of evasion techniques and is able to modulate the host immune system. Antibodies are a key component of pneumococcal immunity, targeting both the capsule polysaccharide and protein antigens on the surface of the bacterium. These antibodies have been shown to play a variety of roles including increasing opsonophagocytic activity, enzymatic and toxin neutralization, reducing bacterial adherence, and altering bacterial gene expression. In this review, we describe targets of anti-pneumococcal antibodies and describe antibody functions and effectiveness against S. pneumoniae.
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Affiliation(s)
- Aaron D. Gingerich
- Center for Vaccines and Immunology, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Jarrod J. Mousa
- Center for Vaccines and Immunology, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
- Department of Biochemistry and Molecular Biology, Franklin College of Arts and Sciences, University of Georgia, Athens, GA, United States
- *Correspondence: Jarrod J. Mousa,
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3
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Marshall H, José RJ, Kilian M, Petersen FC, Brown JS. Effects of Expression of Streptococcus pneumoniae PspC on the Ability of Streptococcus mitis to Evade Complement-Mediated Immunity. Front Microbiol 2021; 12:773877. [PMID: 34880844 PMCID: PMC8646030 DOI: 10.3389/fmicb.2021.773877] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 11/01/2021] [Indexed: 11/13/2022] Open
Abstract
Streptococcus pneumoniae and Streptococcus mitis are genetically closely related and both frequently colonise the naso-oropharynx, yet S. pneumoniae is a common cause of invasive infections whereas S. mitis is only weakly pathogenic. We hypothesise that sensitivity to innate immunity may underlie these differences in virulence phenotype. We compared the sensitivity of S. pneumoniae and S. mitis strains to complement-mediated immunity, demonstrating S. mitis strains were susceptible to complement-mediated opsonophagocytosis. S. pneumoniae resistance to complement is partially dependent on binding of the complement regulator Factor H by the surface protein PspC. However, S. mitis was unable to bind factor H. The S. pneumoniae TIGR4 strain pspC was expressed in the S. mitis SK142 strain to create a S. mitis pspC+ strain. Immunoblots demonstrated the S. mitis pspC+ strain expressed PspC, and flow cytometry confirmed this resulted in Factor H binding to S. mitis, reduced susceptibility to complement and improved survival in whole human blood compared to the wild-type S. mitis strain. However, in mouse models the S. mitis pspC+ strain remained unable to establish persistent infection. Unlike S. pneumoniae strains, culture in serum or blood did not support increased CFU of the S. mitis strains. These results suggest S. mitis is highly sensitive to opsonisation with complement partially due to an inability to bind Factor H, but even when complement sensitivity was reduced by expression of pspC, poor growth in physiological fluid limited the virulence of S. mitis in mice.
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Affiliation(s)
- Helina Marshall
- Centre for Inflammation and Tissue Repair, UCL Respiratory, Department of Medicine, Royal Free and University College Medical School, University College London, London, United Kingdom.,Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
| | - Ricardo J José
- Centre for Inflammation and Tissue Repair, UCL Respiratory, Department of Medicine, Royal Free and University College Medical School, University College London, London, United Kingdom
| | - Mogens Kilian
- Department of Biomedicine, Faculty of Health, Aarhus University, Aarhus, Denmark
| | - Fernanda C Petersen
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - Jeremy S Brown
- Centre for Inflammation and Tissue Repair, UCL Respiratory, Department of Medicine, Royal Free and University College Medical School, University College London, London, United Kingdom
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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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Venkataranganayaka Abhilasha K, Kedihithlu Marathe G. Bacterial lipoproteins in sepsis. Immunobiology 2021; 226:152128. [PMID: 34488139 DOI: 10.1016/j.imbio.2021.152128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 07/09/2021] [Accepted: 08/10/2021] [Indexed: 01/05/2023]
Abstract
Bacterial lipoproteins are membrane proteins derived from both gram-negative and gram-positive bacteria. They seem to have diverse functions not only on bacterial growth, but also play an important role in host's virulence. Bacterial lipoproteins exert their action on host immune cells via TLR2/1 or TLR2/6. Therefore, bacterial lipoproteins also need to be considered while addressing bacterial pathogenicity besides classical bacterial endotoxin like LPS and other microbial associated molecular patterns such as LTA, and peptidoglycans. In this mini-review, we provide an overview of general bacterial lipoprotein biosynthesis and the need to understand the lipoprotein-mediated pathogenicity in diseases like sepsis.
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Affiliation(s)
- Kandahalli Venkataranganayaka Abhilasha
- Department of Studies in Biochemistry, University of Mysore, Manasagangothri, Mysuru 570006, Karnataka, India; Cancer and Developmental Biology Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | - Gopal Kedihithlu Marathe
- Department of Studies in Biochemistry, University of Mysore, Manasagangothri, Mysuru 570006, Karnataka, India; Department of Studies in Molecular Biology, University of Mysore, Manasagangothri, Mysuru 570006, Karnataka, India.
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7
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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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8
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Hirschmann S, Gómez-Mejia A, Kohler TP, Voß F, Rohde M, Brendel M, Hammerschmidt S. The Two-Component System 09 of Streptococcus pneumoniae Is Important for Metabolic Fitness and Resistance during Dissemination in the Host. Microorganisms 2021; 9:microorganisms9071365. [PMID: 34201716 PMCID: PMC8306541 DOI: 10.3390/microorganisms9071365] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/12/2021] [Accepted: 06/18/2021] [Indexed: 11/24/2022] Open
Abstract
The two-component regulatory system 09 of Streptococcus pneumoniae has been shown to modulate resistance against oxidative stress as well as capsule expression. These data and the implication of TCS09 in cell wall integrity have been shown for serotype 2 strain D39. Other data have suggested strain-specific regulatory effects of TCS09. Contradictory data are known on the impact of TCS09 on virulence, but all have been explored using only the rr09-mutant. In this study, we have therefore deleted one or both components of the TCS09 (SP_0661 and SP_0662) in serotype 4 S. pneumoniae TIGR4. In vitro growth assays in chemically defined medium (CDM) using sucrose or lactose as a carbon source indicated a delayed growth of nonencapsulated tcs09-mutants, while encapsulated wild-type TIGR4 and tcs09-mutants have reduced growth in CDM with glucose. Using a set of antigen-specific antibodies, immunoblot analysis showed that only the pilus 1 backbone protein RrgB is significantly reduced in TIGR4ΔcpsΔhk09. Electron microscopy, adherence and phagocytosis assays showed no impact of TCS09 on the TIGR4 cell morphology and interaction with host cells. In contrast, in vivo infections and in particular competitive co-infection experiments demonstrated that TCS09 enhances robustness during dissemination in the host by maintaining bacterial fitness.
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Affiliation(s)
- Stephanie Hirschmann
- Center for Functional Genomics of Microbes, Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, 17487 Greifswald, Germany; (S.H.); (A.G.-M.); (T.P.K.); (F.V.); (M.B.)
| | - Alejandro Gómez-Mejia
- Center for Functional Genomics of Microbes, Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, 17487 Greifswald, Germany; (S.H.); (A.G.-M.); (T.P.K.); (F.V.); (M.B.)
| | - Thomas P. Kohler
- Center for Functional Genomics of Microbes, Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, 17487 Greifswald, Germany; (S.H.); (A.G.-M.); (T.P.K.); (F.V.); (M.B.)
| | - Franziska Voß
- Center for Functional Genomics of Microbes, Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, 17487 Greifswald, Germany; (S.H.); (A.G.-M.); (T.P.K.); (F.V.); (M.B.)
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany;
| | - Max Brendel
- Center for Functional Genomics of Microbes, Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, 17487 Greifswald, Germany; (S.H.); (A.G.-M.); (T.P.K.); (F.V.); (M.B.)
| | - Sven Hammerschmidt
- Center for Functional Genomics of Microbes, Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, 17487 Greifswald, Germany; (S.H.); (A.G.-M.); (T.P.K.); (F.V.); (M.B.)
- Correspondence:
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9
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Park SS, Gonzalez-Juarbe N, Martínez E, Hale JY, Lin YH, Huffines JT, Kruckow KL, Briles DE, Orihuela CJ. Streptococcus pneumoniae Binds to Host Lactate Dehydrogenase via PspA and PspC To Enhance Virulence. mBio 2021; 12:e00673-21. [PMID: 33947761 PMCID: PMC8437407 DOI: 10.1128/mbio.00673-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 03/22/2021] [Indexed: 02/06/2023] Open
Abstract
Pneumococcal surface protein A (PspA) and pneumococcal surface protein C (PspC, also called CbpA) are major virulence factors of Streptococcus pneumoniae (Spn). These surface-exposed choline-binding proteins (CBPs) function independently to inhibit opsonization, neutralize antimicrobial factors, or serve as adhesins. PspA and PspC both carry a proline-rich domain (PRD) whose role, other than serving as a flexible connector between the N-terminal and C-terminal domains, was up to this point unknown. Herein, we demonstrate that PspA binds to lactate dehydrogenase (LDH) released from dying host cells during infection. Using recombinant versions of PspA and isogenic mutants lacking PspA or specific domains of PspA, this property was mapped to a conserved 22-amino-acid nonproline block (NPB) found within the PRD of most PspAs and PspCs. The NPB of PspA had specific affinity for LDH-A, which converts pyruvate to lactate. In a mouse model of pneumonia, preincubation of Spn carrying NPB-bearing PspA with LDH-A resulted in increased bacterial titers in the lungs. In contrast, incubation of Spn carrying a version of PspA lacking the NPB with LDH-A or incubation of wild-type Spn with enzymatically inactive LDH-A did not enhance virulence. Preincubation of NPB-bearing Spn with lactate alone enhanced virulence in a pneumonia model, indicating exogenous lactate production by Spn-bound LDH-A had an important role in pneumococcal pathogenesis. Our observations show that lung LDH, released during the infection, is an important binding target for Spn via PspA/PspC and that pneumococci utilize LDH-A derived lactate for their benefit in vivoIMPORTANCEStreptococcus pneumoniae (Spn) is the leading cause of community-acquired pneumonia. PspA and PspC are among its most important virulence factors, and these surface proteins carry the proline-rich domain (PRD), whose role was unknown until now. Herein, we show that a conserved 22-amino-acid nonproline block (NPB) found within most versions of the PRD binds to host-derived lactate dehydrogenase A (LDH-A), a metabolic enzyme which converts pyruvate to lactate. PspA-mediated binding of LDH-A increased Spn titers in the lungs and this required LDH-A enzymatic activity. Enhanced virulence was also observed when Spn was preincubated with lactate, suggesting LDH-A-derived lactate is a vital food source. Our findings define a role for the NPB of the PRD and show that Spn co-opts host enzymes for its benefit. They advance our understanding of pneumococcal pathogenesis and have key implications on the susceptibility of individuals with preexisting airway damage that results in LDH-A release.
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Affiliation(s)
- Sang-Sang Park
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Norberto Gonzalez-Juarbe
- Infectious Diseases and Genomic Medicine Group, J Craig Venter Institute, Rockville, Maryland, USA
| | - Eriel Martínez
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Joanetha Yvette Hale
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Yi-Han Lin
- Infectious Diseases and Genomic Medicine Group, J Craig Venter Institute, Rockville, Maryland, USA
| | - Joshua T Huffines
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Katherine L Kruckow
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - David E Briles
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Carlos J Orihuela
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
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10
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Eichner H, Karlsson J, Spelmink L, Pathak A, Sham LT, Henriques-Normark B, Loh E. RNA thermosensors facilitate Streptococcus pneumoniae and Haemophilus influenzae immune evasion. PLoS Pathog 2021; 17:e1009513. [PMID: 33914847 PMCID: PMC8084184 DOI: 10.1371/journal.ppat.1009513] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 03/29/2021] [Indexed: 11/18/2022] Open
Abstract
Bacterial meningitis is a major cause of death and disability in children worldwide. Two human restricted respiratory pathogens, Streptococcus pneumoniae and Haemophilus influenzae, are the major causative agents of bacterial meningitis, attributing to 200,000 deaths annually. These pathogens are often part of the nasopharyngeal microflora of healthy carriers. However, what factors elicit them to disseminate and cause invasive diseases, remain unknown. Elevated temperature and fever are hallmarks of inflammation triggered by infections and can act as warning signals to pathogens. Here, we investigate whether these respiratory pathogens can sense environmental temperature to evade host complement-mediated killing. We show that productions of two vital virulence factors and vaccine components, the polysaccharide capsules and factor H binding proteins, are temperature dependent, thus influencing serum/opsonophagocytic killing of the bacteria. We identify and characterise four novel RNA thermosensors in S. pneumoniae and H. influenzae, responsible for capsular biosynthesis and production of factor H binding proteins. Our data suggest that these bacteria might have independently co-evolved thermosensing abilities with different RNA sequences but distinct secondary structures to evade the immune system.
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Affiliation(s)
- Hannes Eichner
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - Jens Karlsson
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - Laura Spelmink
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - Anuj Pathak
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - Lok-To Sham
- Infectious Disease Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Birgitta Henriques-Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
- Clinical Microbiology, Bioclinicum, Karolinska University Hospital, Solna, Sweden
- Lee Kong Chian School of Medicine and Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Edmund Loh
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
- Clinical Microbiology, Bioclinicum, Karolinska University Hospital, Solna, Sweden
- Lee Kong Chian School of Medicine and Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
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11
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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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12
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Pneumococcal Choline-Binding Proteins Involved in Virulence as Vaccine Candidates. Vaccines (Basel) 2021; 9:vaccines9020181. [PMID: 33672701 PMCID: PMC7924319 DOI: 10.3390/vaccines9020181] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/15/2021] [Accepted: 02/18/2021] [Indexed: 01/25/2023] Open
Abstract
Streptococcus pneumoniae is a pathogen responsible for millions of deaths worldwide. Currently, the available vaccines for the prevention of S. pneumoniae infections are the 23-valent pneumococcal polysaccharide-based vaccine (PPV-23) and the pneumococcal conjugate vaccines (PCV10 and PCV13). These vaccines only cover some pneumococcal serotypes (up to 100 different serotypes have been identified) and are unable to protect against non-vaccine serotypes and non-encapsulated pneumococci. The emergence of antibiotic-resistant non-vaccine serotypes after these vaccines is an increasing threat. Therefore, there is an urgent need to develop new pneumococcal vaccines which could cover a wide range of serotypes. One of the vaccines most characterized as a prophylactic alternative to current PPV-23 or PCVs is a vaccine based on pneumococcal protein antigens. The choline-binding proteins (CBP) are found in all pneumococcal strains, giving them the characteristic to be potential vaccine candidates as they may protect against different serotypes. In this review, we have focused the attention on different CBPs as vaccine candidates because they are involved in the pathogenesis process, confirming their immunogenicity and protection against pneumococcal infection. The review summarizes the major contribution of these proteins to virulence and reinforces the fact that antibodies elicited against many of them may block or interfere with their role in the infection process.
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13
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Du S, Vilhena C, King S, Sahagún-Ruiz A, Hammerschmidt S, Skerka C, Zipfel PF. Molecular analyses identifies new domains and structural differences among Streptococcus pneumoniae immune evasion proteins PspC and Hic. Sci Rep 2021; 11:1701. [PMID: 33462258 PMCID: PMC7814132 DOI: 10.1038/s41598-020-79362-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/07/2020] [Indexed: 12/13/2022] Open
Abstract
The PspC and Hic proteins of Streptococcuspneumoniae are some of the most variable microbial immune evasion proteins identified to date. Due to structural similarities and conserved binding profiles, it was assumed for a long time that these pneumococcal surface proteins represent a protein family comprised of eleven subgroups. Recently, however, the evaluation of more proteins revealed a greater diversity of individual proteins. In contrast to previous assumptions a pattern evaluation of six PspC and five Hic variants, each representing one of the previously defined subgroups, revealed distinct structural and likely functionally regions of the proteins, and identified nine new domains and new domain alternates. Several domains are unique to PspC and Hic variants, while other domains are also present in other virulence factors encoded by pneumococci and other bacterial pathogens. This knowledge improved pattern evaluation at the level of full-length proteins, allowed a sequence comparison at the domain level and identified domains with a modular composition. This novel strategy increased understanding of individual proteins variability and modular domain composition, enabled a structural and functional characterization at the domain level and furthermore revealed substantial structural differences between PspC and Hic proteins. Given the exceptional genomic diversity of the multifunctional PspC and Hic proteins a detailed structural and functional evaluation need to be performed at the strain level. Such knowledge will also be useful for molecular strain typing and characterizing PspC and Hic proteins from new clinical S. pneumoniae strains.
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Affiliation(s)
- Shanshan Du
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Cláudia Vilhena
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Samantha King
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA.,Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| | - Alfredo Sahagún-Ruiz
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany.,Molecular Immunology Laboratory, Department of Microbiology and Immunology, Faculty of Veterinary Medicine and Animal Husbandry, National Autonomous University of Mexico, Mexico City, Mexico
| | - Sven Hammerschmidt
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Christine Skerka
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Peter F Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany. .,Institute of Microbiology, Friedrich-Schiller-University, Jena, Germany.
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14
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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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15
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Innate Immune Pattern Recognition Receptors of Mycobacterium tuberculosis: Nature and Consequences for Pathogenesis of Tuberculosis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1313:179-215. [PMID: 34661896 DOI: 10.1007/978-3-030-67452-6_9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Innate immunity against Mycobacterium tuberculosis is a critical early response to prevent the establishment of the infection. Despite recent advances in understanding the host-pathogen dialogue in the early stages of tuberculosis (TB), much has yet to be learnt. The nature and consequences of this dialogue ultimately determine the path of infection: namely, either early clearance of M. tuberculosis, or establishment of M. tuberculosis infection leading to active TB disease and/or latent TB infection. On the frontline in innate immunity are pattern recognition receptors (PRRs), with soluble factors (e.g. collectins and complement) and cell surface factors (e.g. Toll-like receptors and other C-type lectin receptors (Dectin 1/2, Nod-like receptors, DC-SIGN, Mincle, mannose receptor, and MCL) that play a central role in recognising M. tuberculosis and facilitating its clearance. However, in a 'double-edged sword' scenario, these factors can also be involved in enhancement of pathogenesis as well. Furthermore, innate immunity is also a critical bridge in establishing the subsequent adaptive immune response, which is also responsible for granuloma formation that cordons off M. tuberculosis infection, establishing latency and acting as a reservoir for bacterial persistence and dissemination of future disease. This chapter discusses the current understanding of pattern recognition of M. tuberculosis by innate immunity and the role this plays in the pathogenesis and protection against TB.
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16
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Chaguza C, Yang M, Cornick JE, du Plessis M, Gladstone RA, Kwambana-Adams BA, Lo SW, Ebruke C, Tonkin-Hill G, Peno C, Senghore M, Obaro SK, Ousmane S, Pluschke G, Collard JM, Sigaùque B, French N, Klugman KP, Heyderman RS, McGee L, Antonio M, Breiman RF, von Gottberg A, Everett DB, Kadioglu A, Bentley SD. Bacterial genome-wide association study of hyper-virulent pneumococcal serotype 1 identifies genetic variation associated with neurotropism. Commun Biol 2020; 3:559. [PMID: 33033372 PMCID: PMC7545184 DOI: 10.1038/s42003-020-01290-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/11/2020] [Indexed: 12/19/2022] Open
Abstract
Hyper-virulent Streptococcus pneumoniae serotype 1 strains are endemic in Sub-Saharan Africa and frequently cause lethal meningitis outbreaks. It remains unknown whether genetic variation in serotype 1 strains modulates tropism into cerebrospinal fluid to cause central nervous system (CNS) infections, particularly meningitis. Here, we address this question through a large-scale linear mixed model genome-wide association study of 909 African pneumococcal serotype 1 isolates collected from CNS and non-CNS human samples. By controlling for host age, geography, and strain population structure, we identify genome-wide statistically significant genotype-phenotype associations in surface-exposed choline-binding (P = 5.00 × 10-08) and helicase proteins (P = 1.32 × 10-06) important for invasion, immune evasion and pneumococcal tropism to CNS. The small effect sizes and negligible heritability indicated that causation of CNS infection requires multiple genetic and other factors reflecting a complex and polygenic aetiology. Our findings suggest that certain pathogen genetic variation modulate pneumococcal survival and tropism to CNS tissue, and therefore, virulence for meningitis.
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Affiliation(s)
- Chrispin Chaguza
- Parasites and Microbes Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, UK.
- Darwin College, University of Cambridge, Silver Street, Cambridge, UK.
| | - Marie Yang
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Jennifer E Cornick
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Mignon du Plessis
- Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases, Johannesburg, South Africa
- School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Rebecca A Gladstone
- Parasites and Microbes Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, UK
| | - Brenda A Kwambana-Adams
- NIHR Global Health Research Unit on Mucosal Pathogens, Division of Infection and Immunity, University College London, London, UK
- Medical Research Council (MRC) Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Stephanie W Lo
- Parasites and Microbes Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, UK
| | - Chinelo Ebruke
- Medical Research Council (MRC) Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Gerry Tonkin-Hill
- Parasites and Microbes Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, UK
| | - Chikondi Peno
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- MRC Centre for Inflammation Research, Queens Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Madikay Senghore
- Medical Research Council (MRC) Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard TH Chan School of Public Health, Boston, MA, USA
| | - Stephen K Obaro
- Division of Pediatric Infectious Disease, University of Nebraska Medical Center Omaha, Omaha, NE, USA
- International Foundation against Infectious Diseases in Nigeria, Abuja, Nigeria
| | - Sani Ousmane
- Centre de Recherche Médicale et Sanitaire, Niamey, Niger
| | - Gerd Pluschke
- Swiss Tropical and Public Health Institute, Basel, Switzerland
| | | | - Betuel Sigaùque
- Centro de Investigação em Saúde da Manhiça, Maputo, Mozambique
| | - Neil French
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Keith P Klugman
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Robert S Heyderman
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- NIHR Global Health Research Unit on Mucosal Pathogens, Division of Infection and Immunity, University College London, London, UK
| | - Lesley McGee
- Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Martin Antonio
- Medical Research Council (MRC) Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
- Warwick Medical School, University of Warwick, Coventry, UK
| | - Robert F Breiman
- Emory Global Health Institute, Emory University, Atlanta, GA, USA
| | - Anne von Gottberg
- Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases, Johannesburg, South Africa
- School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Dean B Everett
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- MRC Centre for Inflammation Research, Queens Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Aras Kadioglu
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Stephen D Bentley
- Parasites and Microbes Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, UK.
- Department of Pathology, University of Cambridge, Cambridge, UK.
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17
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Development of Next Generation Streptococcus pneumoniae Vaccines Conferring Broad Protection. Vaccines (Basel) 2020; 8:vaccines8010132. [PMID: 32192117 PMCID: PMC7157650 DOI: 10.3390/vaccines8010132] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/22/2020] [Accepted: 02/29/2020] [Indexed: 02/06/2023] Open
Abstract
Streptococcus pneumoniae is a major pathogen causing pneumonia with over 2 million deaths annually, especially in young children and the elderly. To date, at least 98 different pneumococcal capsular serotypes have been identified. Currently, the vaccines for prevention of S. pneumoniae infections are the 23-valent pneumococcal polysaccharide-based vaccine (PPV23) and the pneumococcal conjugate vaccines (PCV10 and PCV13). These vaccines only cover some pneumococcal serotypes and are unable to protect against non-vaccine serotypes and unencapsulated S. pneumoniae. This has led to a rapid increase in antibiotic-resistant non-vaccine serotypes. Hence, there is an urgent need to develop new, effective, and affordable pneumococcal vaccines, which could cover a wide range of serotypes. This review discusses the new approaches to develop effective vaccines with broad serotype coverage as well as recent development of promising pneumococcal vaccines in clinical trials. New vaccine candidates are the inactivated whole-cell vaccine strain (Δpep27ΔcomD mutant) constructed by mutations of specific genes and several protein-based S. pneumoniae vaccines using conserved pneumococcal antigens, such as lipoprotein and surface-exposed protein (PspA). Among the vaccines in Phase 3 clinical trials are the pneumococcal conjugate vaccines, PCV-15 (V114) and 20vPnC. The inactivated whole-cell and several protein-based vaccines are either in Phase 1 or 2 trials. Furthermore, the recent progress of nanoparticles that play important roles as delivery systems and adjuvants to improve the performance, as well as the immunogenicity of the nanovaccines, are reviewed.
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18
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Morais V, Texeira E, Suarez N. Next-Generation Whole-Cell Pneumococcal Vaccine. Vaccines (Basel) 2019; 7:E151. [PMID: 31623286 PMCID: PMC6963273 DOI: 10.3390/vaccines7040151] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 10/04/2019] [Accepted: 10/14/2019] [Indexed: 11/16/2022] Open
Abstract
Streptococcus pneumoniae remains a major public health hazard. Although Pneumococcal Conjugate Vaccines (PCVs) are available and have significantly reduced the rate of invasive pneumococcal diseases, there is still a need for new vaccines with unlimited serotype coverage, long-lasting protection, and lower cost to be developed. One of the most promising candidates is the Whole-Cell Pneumococcal Vaccine (WCV). The new generation of whole-cell vaccines is based on an unencapsulated serotype that allows the expression of many bacterial antigens at a lower cost than a recombinant vaccine. These vaccines have been extensively studied, are currently in human trial phase 1/2, and seem to be the best treatment choice for pneumococcal diseases, especially for developing countries.
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Affiliation(s)
- Victor Morais
- Department of Biotechnology, Institute of Hygiene, Faculty of Medicine, University of the Republic, Montevideo 11600, Uruguay.
| | - Esther Texeira
- Department of Biotechnology, Institute of Hygiene, Faculty of Medicine, University of the Republic, Montevideo 11600, Uruguay.
| | - Norma Suarez
- Department of Biotechnology, Institute of Hygiene, Faculty of Medicine, University of the Republic, Montevideo 11600, Uruguay.
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19
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Morris FC, Dexter C, Kostoulias X, Uddin MI, Peleg AY. The Mechanisms of Disease Caused by Acinetobacter baumannii. Front Microbiol 2019; 10:1601. [PMID: 31379771 PMCID: PMC6650576 DOI: 10.3389/fmicb.2019.01601] [Citation(s) in RCA: 155] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 06/26/2019] [Indexed: 01/29/2023] Open
Abstract
Acinetobacter baumannii is a Gram negative opportunistic pathogen that has demonstrated a significant insurgence in the prevalence of infections over recent decades. With only a limited number of “traditional” virulence factors, the mechanisms underlying the success of this pathogen remain of great interest. Major advances have been made in the tools, reagents, and models to study A. baumannii pathogenesis, and this has resulted in a substantial increase in knowledge. This article provides a comprehensive review of the bacterial virulence factors, the host immune responses, and animal models applicable for the study of this important human pathogen. Collating the most recent evidence characterizing bacterial virulence factors, their cellular targets and genetic regulation, we have encompassed numerous aspects important to the success of this pathogen, including membrane proteins and cell surface adaptations promoting immune evasion, mechanisms for nutrient acquisition and community interactions. The role of innate and adaptive immune responses is reviewed and areas of paucity in our understanding are highlighted. Finally, with the vast expansion of available animal models over recent years, we have evaluated those suitable for use in the study of Acinetobacter disease, discussing their advantages and limitations.
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Affiliation(s)
- Faye C Morris
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Carina Dexter
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Xenia Kostoulias
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Muhammad Ikhtear Uddin
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Anton Y Peleg
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, VIC, Australia
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20
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van den Broek B, van der Flier M, de Groot R, de Jonge MI, Langereis JD. Common Genetic Variants in the Complement System and their Potential Link with Disease Susceptibility and Outcome of Invasive Bacterial Infection. J Innate Immun 2019; 12:131-141. [PMID: 31269507 DOI: 10.1159/000500545] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 04/19/2019] [Indexed: 01/01/2023] Open
Abstract
Streptococcus pneumoniae and Neisseria meningitidis are pathogens that frequently colonize the nasopharynx in an asymptomatic manner but are also a cause of invasive bacterial infections mainly in young children. The complement system plays a crucial role in humoral immunity, complementing the ability of antibodies to clear microbes, thereby protecting the host against bacterial infections, including S. pneumoniae and N. meningitidis. While it is widely accepted that complement deficiencies due to rare genetic variants increase the risk for invasive bacterial infection, not much is known about the common genetic variants in the complement system in relation to disease susceptibility. In this review, we provide an overview of the effects of common genetic variants on complement activation and on complement-mediated inflammation.
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Affiliation(s)
- Bryan van den Broek
- Paediatric Infectious Diseases and Immunology, Amalia Children's Hospital, Nijmegen, The Netherlands.,Section Paediatric Infectious Diseases, Laboratory of Medical Immunology, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, The Netherlands.,Radboud Center for Infectious Diseases, Radboudumc, Nijmegen, The Netherlands
| | - Michiel van der Flier
- Paediatric Infectious Diseases and Immunology, Amalia Children's Hospital, Nijmegen, The Netherlands.,Expertise Center for Immunodeficiency and Auto inflammation (REIA), Radboudumc, Nijmegen, The Netherlands.,Section Paediatric Infectious Diseases, Laboratory of Medical Immunology, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, The Netherlands.,Radboud Center for Infectious Diseases, Radboudumc, Nijmegen, The Netherlands
| | - Ronald de Groot
- Section Paediatric Infectious Diseases, Laboratory of Medical Immunology, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, The Netherlands.,Radboud Center for Infectious Diseases, Radboudumc, Nijmegen, The Netherlands
| | - Marien I de Jonge
- Section Paediatric Infectious Diseases, Laboratory of Medical Immunology, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, The Netherlands.,Radboud Center for Infectious Diseases, Radboudumc, Nijmegen, The Netherlands
| | - Jeroen D Langereis
- Section Paediatric Infectious Diseases, Laboratory of Medical Immunology, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, The Netherlands, .,Radboud Center for Infectious Diseases, Radboudumc, Nijmegen, The Netherlands,
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21
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Crystal structure of the choline-binding protein CbpJ from Streptococcus pneumoniae. Biochem Biophys Res Commun 2019; 514:1192-1197. [PMID: 31104766 DOI: 10.1016/j.bbrc.2019.05.053] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 05/06/2019] [Indexed: 02/04/2023]
Abstract
The choline-binding proteins play essential roles in pneumococcal colonization and virulence. It has been suggested that the choline-binding protein J (termed CbpJ; encoded by the gene sp_0378) from Streptococcus pneumoniae TIGR4 involves in the colonization in host and contributes to evasion of neutrophil killing. Here we report the 2.0 Å crystal structure of CbpJ in complex with choline. CbpJ consists of an N-terminal putative functional domain (N-domain) followed by a C-terminal choline-binding domain (CBD). The N-domain harbors four degenerated choline-binding repeats (CBRs) that lose the capacity of binding to choline, whereas the CBD is composed of seven typical CBRs. Further functional assays showed that the CBD contributes to the pneumococcal adhesion to human lung epithelial cell A549. These findings provide insights into the pneumococcal pathogenesis and broaden our understanding on the functions of choline-binding proteins.
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22
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Abstract
ABSTRACT
Streptococcus pneumoniae
undergoes phase variation or spontaneous, reversible phenotypic variation in colony opacity, encapsulation, and pilus expression. The variation in colony opacity appears to occur in all strains, whereas the switches in the production of the capsule and pilus have been observed in several strains. This chapter elaborates on the variation in colony opacity since this phenomenon has been extensively characterized.
S. pneumoniae
produces opaque and transparent colonies on the translucent agar medium. The different colony phases are fundamentally distinct phenotypes in their metabolism and multiple characteristics, as exemplified by cell surface features and phenotypes in colonization and virulence. Opaque variants, which express more capsular polysaccharides and fewer teichoic acids, are more virulent in animal models of sepsis but colonize the nasopharynx poorly. In contrast, transparent variants, with fewer capsular polysaccharides and more teichoic acid, colonize the nasopharynx in animal models more efficiently but are relatively avirulent. Lastly, pneumococcal opacity variants are generated by differential methylation of the genome DNA variation. The reversible switch in the methylation pattern is caused by DNA inversions in three homologous
hsdS
genes of the colony opacity determinant (
cod
) or SpnD39III locus, a conserved type I restriction-modification (RM) system. The
hsdS
gene encodes the sequence recognition subunit of the type I RM DNA methyltransferase. The combination of DNA inversion and differential methylation, a complex mechanism of phase variation, generates a mixed population that may allow for the selection of organisms
in vivo
with characteristics permissive for either carriage or systemic infection.
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Comparison of four adjuvants revealed the strongest protection against lethal pneumococcal challenge following immunization with PsaA-PspA fusion protein and AS02 as adjuvant. Med Microbiol Immunol 2019; 208:215-226. [PMID: 30707297 DOI: 10.1007/s00430-019-00579-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 01/14/2019] [Indexed: 10/27/2022]
Abstract
Streptococcuspneumoniae, or pneumococcus, is a major respiratory-tract pathogen that causes high levels of mortality and morbidity in infants and elderly individuals. Despite the development of various capsular polysaccharide vaccines to prevent pneumococcal disease, it remains epidemic. Pneumococcal surface protein A (PspA) is a highly immunogenic surface protein existing in all strains of S. pneumoniae, and it can elicit immunizing protection against pneumococcal infection. In our previous studies, a fusion protein (PsaA-PspA23), consisting of PspA and pneumococcal surface antigen A (PsaA), displayed greater immunogenicity and provided better protection in mice against S. pneumoniae strains than either PsaA or PspA. In this study, the fusion protein PsaA-PspA23, together with PspA4, was formulated with four adjuvants Al(OH)3, MF59, AS03, and AS02, and subsequently subjected to dose optimization and immunological evaluation for determination of the antibody titers, bacterial burden, survival rates, and levels of cytokines in mice. All vaccines with high adjuvant doses displayed higher antigen-specific immunoglobulin G (IgG) titers. Bacterial burdens were notably decreased to different extents in the lungs and blood of mice immunized with the antigen and various adjuvants. Among these adjuvants, AS02 provided outstanding protection against challenge with pathogenic bacteria from different families and clades; it also induced high titers of IgG1 and IgG2a. Moreover, only AS02 elicited high levels of cytokines, such as TNF-α, IFN-γ, IL-2, and IL-4. These results suggest that PsaA-PspA23 and PspA4 formulated with AS02 may potentially be used as a subunit vaccine against deadly pneumococcal infection.
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The Pneumococcal Surface Proteins PspA and PspC Sequester Host C4-Binding Protein To Inactivate Complement C4b on the Bacterial Surface. Infect Immun 2018; 87:IAI.00742-18. [PMID: 30323030 DOI: 10.1128/iai.00742-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 10/11/2018] [Indexed: 12/15/2022] Open
Abstract
Complement is a critical component of antimicrobial immunity. Various complement regulatory proteins prevent host cells from being attacked. Many pathogens have acquired the ability to sequester complement regulators from host plasma to evade complement attack. We describe here how Streptococcus pneumoniae adopts a strategy to prevent the formation of the C3 convertase C4bC2a by the rapid conversion of surface bound C4b and iC4b into C4dg, which remains bound to the bacterial surface but no longer forms a convertase complex. Noncapsular virulence factors on the pneumococcus are thought to facilitate this process by sequestering C4b-binding protein (C4BP) from host plasma. When S. pneumoniae D39 was opsonized with human serum, the larger C4 activation products C4b and iC4b were undetectable, but the bacteria were liberally decorated with C4dg and C4BP. With targeted deletions of either PspA or PspC, C4BP deposition was markedly reduced, and there was a corresponding reduction in C4dg and an increase in the deposition of C4b and iC4b. The effect was greatest when PspA and PspC were both knocked out. Infection experiments in mice indicated that the deletion of PspA and/or PspC resulted in the loss of bacterial pathogenicity. Recombinant PspA and PspC both bound serum C4BP, and both led to increased C4b and reduced C4dg deposition on S. pneumoniae D39. We conclude that PspA and PspC help the pneumococcus to evade complement attack by binding C4BP and so inactivating C4b.
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25
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Leonard A, Lalk M. Infection and metabolism – Streptococcus pneumoniae metabolism facing the host environment. Cytokine 2018; 112:75-86. [DOI: 10.1016/j.cyto.2018.07.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 07/15/2018] [Accepted: 07/16/2018] [Indexed: 12/21/2022]
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Pathak A, Bergstrand J, Sender V, Spelmink L, Aschtgen MS, Muschiol S, Widengren J, Henriques-Normark B. Factor H binding proteins protect division septa on encapsulated Streptococcus pneumoniae against complement C3b deposition and amplification. Nat Commun 2018; 9:3398. [PMID: 30139996 PMCID: PMC6107515 DOI: 10.1038/s41467-018-05494-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 07/05/2018] [Indexed: 01/20/2023] Open
Abstract
Streptococcus pneumoniae evades C3-mediated opsonization and effector functions by expressing an immuno-protective polysaccharide capsule and Factor H (FH)-binding proteins. Here we use super-resolution microscopy, mutants and functional analysis to show how these two defense mechanisms are functionally and spatially coordinated on the bacterial cell surface. We show that the pneumococcal capsule is less abundant at the cell wall septum, providing C3/C3b entry to underlying nucleophilic targets. Evasion of C3b deposition at division septa and lateral amplification underneath the capsule requires localization of the FH-binding protein PspC at division sites. Most pneumococcal strains have one PspC protein, but successful lineages in colonization and disease may have two, PspC1 and PspC2, that we show affect virulence differently. We find that spatial localization of these FH-recruiting proteins relative to division septa and capsular layer is instrumental for pneumococci to resist complement-mediated opsonophagocytosis, formation of membrane-attack complexes, and for the function as adhesins. Streptococcus pneumoniae evades the action of the complement system by expressing an immuno-protective polysaccharide capsule as well as Factor H-binding proteins. Here, Pathak et al. show that these two defence mechanisms are functionally and spatially coordinated on the bacterial cell surface.
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Affiliation(s)
- Anuj Pathak
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77, Stockholm, Sweden
| | - Jan Bergstrand
- Department Applied Physics, Royal Institute of Technology (KTH), Experimental Biomolecular Physics, SE-106 91, Stockholm, Sweden
| | - Vicky Sender
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77, Stockholm, Sweden
| | - Laura Spelmink
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77, Stockholm, Sweden
| | - Marie-Stephanie Aschtgen
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77, Stockholm, Sweden
| | - Sandra Muschiol
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77, Stockholm, Sweden
| | - Jerker Widengren
- Department Applied Physics, Royal Institute of Technology (KTH), Experimental Biomolecular Physics, SE-106 91, Stockholm, Sweden
| | - Birgitta Henriques-Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77, Stockholm, Sweden. .,Lee Kong Chian School of Medicine (LKC) and Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, 639798, Singapore. .,Department of Clinical Microbiology, Karolinska University Hospital, SE-171 76, Stockholm, Sweden.
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Antibiotic Susceptibility and Prevalence of Adhesion Genes in Streptococcus pneumoniae Isolates Detected in Carrier Children in Tehran. Jundishapur J Microbiol 2018. [DOI: 10.5812/jjm.13256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Abstract
Gram-positive bacteria, including the major respiratory pathogen Streptococcus pneumoniae, were recently shown to produce extracellular vesicles (EVs) that likely originate from the plasma membrane and are released into the extracellular environment. EVs may function as cargo for many bacterial proteins, however, their involvement in cellular processes and their interactions with the innate immune system are poorly understood. Here, EVs from pneumococci were characterized and their immunomodulatory effects investigated. Pneumococcal EVs were protruding from the bacterial surface and released into the medium as 25 to 250 nm lipid stained vesicles containing a large number of cytosolic, membrane, and surface-associated proteins. The cytosolic pore-forming toxin pneumolysin was significantly enriched in EVs compared to a total bacterial lysate but was not required for EV formation. Pneumococcal EVs were internalized into A549 lung epithelial cells and human monocyte-derived dendritic cells and induced proinflammatory cytokine responses irrespective of pneumolysin content. EVs from encapsulated pneumococci were recognized by serum proteins, resulting in C3b deposition and formation of C5b-9 membrane attack complexes as well as factor H recruitment, depending on the presence of the choline binding protein PspC. Addition of EVs to human serum decreased opsonophagocytic killing of encapsulated pneumococci. Our data suggest that EVs may act in an immunomodulatory manner by allowing delivery of vesicle-associated proteins and other macromolecules into host cells. In addition, EVs expose targets for complement factors in serum, promoting pneumococcal evasion of humoral host defense. Streptococcus pneumoniae is a major contributor to morbidity and mortality worldwide, being the major cause of milder respiratory tract infections such as otitis and sinusitis and of severe infections such as community-acquired pneumonia, with or without septicemia, and meningitis. More knowledge is needed on how pneumococci interact with the host, deliver virulence factors, and activate immune defenses. Here we show that pneumococci form extracellular vesicles that emanate from the plasma membrane and contain virulence properties, including enrichment of pneumolysin. We found that pneumococcal vesicles can be internalized into epithelial and dendritic cells and bind complement proteins, thereby promoting pneumococcal evasion of complement-mediated opsonophagocytosis. They also induce pneumolysin-independent proinflammatory responses. We suggest that these vesicles can function as a mechanism for delivery of pneumococcal proteins and other immunomodulatory components into host cells and help pneumococci to avoid complement deposition and phagocytosis-mediated killing, thereby possibly contributing to the symptoms found in pneumococcal infections.
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29
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Antigenic Variation in Streptococcus pneumoniae PspC Promotes Immune Escape in the Presence of Variant-Specific Immunity. mBio 2018. [PMID: 29535198 PMCID: PMC5850329 DOI: 10.1128/mbio.00264-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Genomic analysis reveals extensive sequence variation and hot spots of recombination in surface proteins of Streptococcus pneumoniae. While this phenomenon is commonly attributed to diversifying selection by host immune responses, there is little mechanistic evidence for the hypothesis that diversification of surface protein antigens produces an immune escape benefit during infection with S. pneumoniae. Here, we investigate the biological significance of sequence variation within the S. pneumoniae cell wall-associated pneumococcal surface protein C (PspC) protein antigen. Using pspC allelic diversity observed in a large pneumococcal collection, we produced variant-specific protein constructs that span the sequence variability within the pspC locus. We show that antibodies raised against these PspC constructs are variant specific and prevent association between PspC and the complement pathway mediator, human factor H. We found that PspC variants differ in their capacity to bind factor H, suggesting that sequence variation within pspC reflects differences in biological function. Finally, in an antibody-dependent opsonophagocytic assay, S. pneumoniae expressing a PspC variant matching the antibody specificity was killed efficiently. In contrast, killing efficacy was not evident against S. pneumoniae expressing mismatched PspC variants. Our data suggest that antigenic variation within the PspC antigen promotes immune evasion and could confer a fitness benefit during infection. Loci encoding surface protein antigens in Streptococcus pneumoniae are highly polymorphic. It has become a truism that these polymorphisms are the outcome of selective pressure on S. pneumoniae to escape host immunity. However, there is little mechanistic evidence to support the hypothesis that diversifying protein antigens produces a benefit for the bacteria. Using the highly diverse pspC locus, we have now characterized the functional and immune implications of sequence diversity within the PspC protein. We have characterized the spectrum of biological function among diverse PspC variants and show that pspC sequence diversity reflects functional differences. Further, we show that sequence variation in PspC confers an immune escape benefit in the presence of anti-PspC variant-specific immunity. Overall, the results of our studies provide insights into the functional implications of protein sequence diversity and the role of variant-specific immunity in its maintenance.
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30
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Mucosal Infections and Invasive Potential of Nonencapsulated Streptococcus pneumoniae Are Enhanced by Oligopeptide Binding Proteins AliC and AliD. mBio 2018; 9:mBio.02097-17. [PMID: 29339428 PMCID: PMC5770551 DOI: 10.1128/mbio.02097-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nonencapsulated Streptococcus pneumoniae (NESp) is an emerging human pathogen that colonizes the nasopharynx and is associated with noninvasive diseases such as otitis media (OM), conjunctivitis, and nonbacteremic pneumonia. Since capsule expression was previously thought to be necessary for establishment of invasive pneumococcal disease (IPD), serotype-specific polysaccharide capsules are targeted by currently licensed pneumococcal vaccines. Yet, NESp expressing oligopeptide binding proteins AliC and AliD have been isolated during IPD. Thus, we hypothesize AliC and AliD are major NESp virulence determinants that facilitate persistence and development of IPD. Our study reveals that NESp expressing AliC and AliD have intensified virulence compared to isogenic mutants. Specifically, we demonstrate AliC and AliD enhance murine nasopharyngeal colonization and pulmonary infection and are required for OM in a chinchilla model. Furthermore, AliC and AliD increase pneumococcal survival in chinchilla whole blood and aid in resistance to killing by human leukocytes. Comparative proteome analysis revealed significant alterations in protein levels when AliC and AliD were absent. Virulence-associated proteins, including a pneumococcal surface protein C variant (CbpAC), were significantly downregulated, while starvation response indicators were upregulated in the double mutant relative to wild-type levels. We also reveal that differentially expressed CbpAC was essential for NESp adherence to epithelial cells, virulence during OM, reduction of C3b deposition on the NESp surface, and binding to nonspecific IgA. Altogether, the rise in NESp prevalence urges the need to understand how NESp establishes disease and persists in a host. This study highlights the roles of AliC, AliD, and CbpAC in the pathogenesis of NESp. Despite the effective, widespread use of licensed pneumococcal vaccines over many decades, pneumococcal infections remain a worldwide burden resulting in high morbidity and mortality. NESp subpopulations are rapidly rising in the wake of capsule-targeted vaccine strategies, yet there is very little knowledge on NESp pathogenic potential and virulence mechanisms. Although NESp lacks a protective capsule, NESp lineages expressing AliC and AliD have been associated with systemic infections. Furthermore, higher antibiotic resistance rates and transformation efficiencies associated with emerging NESp threaten treatment strategies needed to control pneumococcal infections and transmission. Elucidating how NESp survives within a host and establishes disease is necessary for development of broadened pneumococcal prevention methods. Our study identifies virulence determinants and host survival mechanisms employed by NESp with a high pathogenic potential. Moreover, our study also identifies virulence determinants shared by NESp and encapsulated strains that may serve as broad prevention and therapeutic targets.
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31
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Jang AY, Seo HS, Lin S, Chung GH, Kim HW, Lim S, Zhao L, Park IH, Lim JH, Kim KH. Molecular characterization of pneumococcal surface protein K, a potential pneumococcal vaccine antigen. Virulence 2017; 8:875-890. [PMID: 28059611 PMCID: PMC5626202 DOI: 10.1080/21505594.2016.1278334] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 12/19/2016] [Accepted: 12/28/2016] [Indexed: 10/20/2022] Open
Abstract
The pneumococcal capsule is indispensable for pathogenesis in systemic infections; however, many pneumococcal diseases, including conjunctivitis, otitis media, and some systemic infections in immunocompromised patients, are caused by nonencapsulated Streptococcus pneumoniae (NESp). Null capsule clade 1 (NCC1), found in group 2 NESp, expresses pneumococcal surface protein K (PspK) and is becoming prevalent among pneumococcal organisms owing to the widespread use of pneumococcal conjugate vaccines. Despite its clinical importance, the molecular mechanisms underlying the prevalence of NCC1 have not been fully elucidated. Here, we investigated the role of the R3 domain of PspK in the epithelial cell adherence of NCC1. We found that the R3 domain of PspK mediated NCC1 adherence via its direct interaction with the epithelial surface protein annexin A2. Additionally, neutralization with purified recombinant PspK-R3 or rabbit anti-UD:R3 IgG inhibited binding of NESp to lung epithelial cells in vitro. Immunization with the 'repeat' domain of PspK-R3 or PspK-UD:R3 effectively elicited mucosal and systemic immune responses against PspK-R3 and provided protection against nasopharyngeal, lung, and middle ear colonization of NESp in mice. Additionally, we found that rabbit anti-UD:R3 IgG bound to PspC-R1 of the encapsulated TIGR4 strain and that UD:R3 immunization provided protection against nasopharyngeal and lung colonization of TIGR4 and deaths by TIGR4 and D39 in mice. Further studies using 68 pneumococcal clinical isolates showed that 79% of clinical isolates showed cross-reactivity to rabbit anti-UD:R3 IgG. About 87% of serotypes in the 13-valent pneumococcal conjugate vaccine (PCV) and 68% of non-vaccine serotypes were positive for cross-reactivity with rabbit anti-UD:R3 IgG. Thus, the R3 domain of PspK may be an effective vaccine candidate for both NESp and encapsulated Sp.
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Affiliation(s)
- A-Yeung Jang
- Biotechnology Division, Korea Atomic Energy Research Institute, Jeongeup, Republic of Korea
- Department of Biological Sciences, Chonbuk National University, Jeonju, Republic of Korea
| | - Ho Seong Seo
- Biotechnology Division, Korea Atomic Energy Research Institute, Jeongeup, Republic of Korea
| | - Shunmei Lin
- Biotechnology Division, Korea Atomic Energy Research Institute, Jeongeup, Republic of Korea
| | - Gook-Hyun Chung
- Department of Biological Sciences, Chonbuk National University, Jeonju, Republic of Korea
| | - Han Wool Kim
- Center for Vaccine Evaluation and Study, Medical Research Institute, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
| | - Sangyong Lim
- Biotechnology Division, Korea Atomic Energy Research Institute, Jeongeup, Republic of Korea
| | - Lei Zhao
- Biotechnology Division, Korea Atomic Energy Research Institute, Jeongeup, Republic of Korea
| | - In Ho Park
- Center for Vaccine Evaluation and Study, Medical Research Institute, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
| | - Jae Hyang Lim
- Department of Microbiology, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
| | - Kyung-Hyo Kim
- Center for Vaccine Evaluation and Study, Medical Research Institute, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
- Department of Pediatrics, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
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32
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Kerr H, Wong E, Makou E, Yang Y, Marchbank K, Kavanagh D, Richards A, Herbert AP, Barlow PN. Disease-linked mutations in factor H reveal pivotal role of cofactor activity in self-surface-selective regulation of complement activation. J Biol Chem 2017. [PMID: 28637873 PMCID: PMC5555194 DOI: 10.1074/jbc.m117.795088] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Spontaneous activation enables the complement system to respond very rapidly to diverse threats. This activation is efficiently suppressed by complement factor H (CFH) on self-surfaces but not on foreign surfaces. The surface selectivity of CFH, a soluble protein containing 20 complement-control protein modules (CCPs 1-20), may be compromised by disease-linked mutations. However, which of the several functions of CFH drives this self-surface selectivity remains unknown. To address this, we expressed human CFH mutants in Pichia pastoris We found that recombinant I62-CFH (protective against age-related macular degeneration) and V62-CFH functioned equivalently, matching or outperforming plasma-derived CFH, whereas R53H-CFH, linked to atypical hemolytic uremic syndrome (aHUS), was defective in C3bBb decay-accelerating activity (DAA) and factor I cofactor activity (CA). The aHUS-linked CCP 19 mutant D1119G-CFH had virtually no CA on (self-like) sheep erythrocytes (ES) but retained DAA. The aHUS-linked CCP 20 mutant S1191L/V1197A-CFH (LA-CFH) had dramatically reduced CA on ES but was less compromised in DAA. D1119G-CFH and LA-CFH both performed poorly at preventing complement-mediated hemolysis of ES PspCN, a CFH-binding Streptococcus pneumoniae protein domain, binds CFH tightly and increases accessibility of CCPs 19 and 20. PspCN did not improve the DAA of any CFH variant on ES Conversely, PspCN boosted the CA, on ES, of I62-CFH, R53H-CFH, and LA-CFH and also enhanced hemolysis protection by I62-CFH and LA-CFH. We conclude that CCPs 19 and 20 are critical for efficient CA on self-surfaces but less important for DAA. Exposing CCPs 19 and 20 with PspCN and thus enhancing CA on self-surfaces may reverse deficiencies of some CFH variants.
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Affiliation(s)
- Heather Kerr
- From the Schools of Chemistry and Biological Sciences, Joseph Black Building, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - Edwin Wong
- From the Schools of Chemistry and Biological Sciences, Joseph Black Building, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - Elisavet Makou
- From the Schools of Chemistry and Biological Sciences, Joseph Black Building, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - Yi Yang
- From the Schools of Chemistry and Biological Sciences, Joseph Black Building, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - Kevin Marchbank
- From the Schools of Chemistry and Biological Sciences, Joseph Black Building, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - David Kavanagh
- From the Schools of Chemistry and Biological Sciences, Joseph Black Building, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - Anna Richards
- From the Schools of Chemistry and Biological Sciences, Joseph Black Building, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - Andrew P Herbert
- From the Schools of Chemistry and Biological Sciences, Joseph Black Building, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - Paul N Barlow
- From the Schools of Chemistry and Biological Sciences, Joseph Black Building, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
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Andre GO, Converso TR, Politano WR, Ferraz LFC, Ribeiro ML, Leite LCC, Darrieux M. Role of Streptococcus pneumoniae Proteins in Evasion of Complement-Mediated Immunity. Front Microbiol 2017; 8:224. [PMID: 28265264 PMCID: PMC5316553 DOI: 10.3389/fmicb.2017.00224] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 01/31/2017] [Indexed: 12/14/2022] Open
Abstract
The complement system plays a central role in immune defense against Streptococcus pneumoniae. In order to evade complement attack, pneumococci have evolved a number of mechanisms that limit complement mediated opsonization and subsequent phagocytosis. This review focuses on the strategies employed by pneumococci to circumvent complement mediated immunity, both in vitro and in vivo. At last, since many of the proteins involved in interactions with complement components are vaccine candidates in different stages of validation, we explore the use of these antigens alone or in combination, as potential vaccine approaches that aim at elimination or drastic reduction in the ability of this bacterium to evade complement.
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Affiliation(s)
- Greiciely O Andre
- Laboratório de Biologia Celular e Molecular de Microrganismos, Universidade São Francisco Bragança Paulista, Brazil
| | - Thiago R Converso
- Centro de Biotecnologia, Instituto ButantanSão Paulo, Brazil; Programa de Pós-graduação Interunidades em Biotecnologia, Universidade de São PauloSão Paulo, Brazil
| | - Walter R Politano
- Laboratório de Biologia Celular e Molecular de Microrganismos, Universidade São Francisco Bragança Paulista, Brazil
| | - Lucio F C Ferraz
- Laboratório de Biologia Celular e Molecular de Microrganismos, Universidade São Francisco Bragança Paulista, Brazil
| | - Marcelo L Ribeiro
- Laboratório de Farmacologia, Universidade São Francisco Bragança Paulista, Brazil
| | | | - Michelle Darrieux
- Laboratório de Biologia Celular e Molecular de Microrganismos, Universidade São Francisco Bragança Paulista, Brazil
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Argondizzo APC, Rocha-de-Souza CM, de Almeida Santiago M, Galler R, Reis JN, Medeiros MA. Pneumococcal Predictive Proteins Selected by Microbial Genomic Approach Are Serotype Cross-Reactive and Bind to Host Extracellular Matrix Proteins. Appl Biochem Biotechnol 2017; 182:1518-1539. [PMID: 28211009 DOI: 10.1007/s12010-017-2415-6] [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: 10/19/2016] [Accepted: 01/16/2017] [Indexed: 11/30/2022]
Abstract
Streptococcus pneumoniae is a colonizer of the human nasopharynx, which accounts for most of the community-acquired pneumonia cases and can cause non-invasive and invasive diseases. Current available vaccines are serotype-specific and the use of recombinant proteins associated with virulence is an alternative to compose vaccines and to overcome these problems. In a previous work, we describe the identification of proteins in S. pneumoniae by reverse vaccinology and the genetic diversity of these proteins in clinical isolates. It was possible to purify a half of 20 selected proteins in soluble form. The expression of these proteins on the pneumococcal cells surface was confirmed by flow cytometry. We demonstrated that some of these proteins were able to bind to extracellular matrix proteins and were recognized by sera from patients with pneumococcal meningitis infection caused by several pneumococcal serotypes. In this context, our results suggest that these proteins may play a role in pneumococcal pathogenesis and might be considered as potential vaccine candidates.
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Affiliation(s)
- Ana Paula Corrêa Argondizzo
- Laboratory of Recombinant Technology, Bio-Manguinhos, Brazilian Health Ministry, FIOCRUZ, Rio de Janeiro, Brazil.
| | - Cláudio Marcos Rocha-de-Souza
- Research Laboratory of Hospital Infection, Collection Hospital Origin bacteria cultures, Instituto Oswaldo Cruz, Brazilian Health Ministry, FIOCRUZ, Rio de Janeiro, Brazil
| | - Marta de Almeida Santiago
- Laboratory of Diagnostic Technology, Bio-Manguinhos, Brazilian Health Ministry, FIOCRUZ, Rio de Janeiro, Brazil
| | - Ricardo Galler
- Fiocruz, Bio-Manguinhos, Brazilian Health Ministry, Rio de Janeiro, Brazil
| | - Joice Neves Reis
- School of Pharmacy, Federal University of Bahia, Salvador, BA, Brazil
| | - Marco Alberto Medeiros
- Laboratory of Recombinant Technology, Bio-Manguinhos, Brazilian Health Ministry, FIOCRUZ, Rio de Janeiro, Brazil
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35
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Li X, Liu P, Gan S, Zhang C, Zheng Y, Jiang Y, Yuan Y. Mechanisms of Host-Pathogen Protein Complex Formation and Bacterial Immune Evasion of Streptococcus suis Protein Fhb. J Biol Chem 2016; 291:17122-32. [PMID: 27342778 DOI: 10.1074/jbc.m116.719443] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Indexed: 12/26/2022] Open
Abstract
Streptococcus suis serotype 2 (S. suis 2)-induced sepsis and meningitis are often accompanied by bacteremia. The evasion of polymorphonuclear leukocyte-mediated phagocytic clearance is central to the establishment of bacteremia caused by S. suis 2 and is facilitated by the ability of factor H (FH)-binding protein (Fhb) to bind FH on the bacterial surface, thereby impeding alternative pathway complement activation and phagocytic clearance. Here, C3b/C3d was found to bind to Fhb, along with FH, forming a large immune complex. The formation of this immune complex was mediated by domain II of Fhb via electrostatic and hydrophobic interactions, which, to our knowledge, is a new type of interaction. Interestingly, Fhb was found to be associated with the cell envelope and also present in the culture supernatant, where secreted Fhb inhibited complement activation via interactions with domain II, thereby enhancing antiphagocytic clearance by polymorphonuclear leukocytes. Thus, Fhb is a multifunctional bacterial protein, which binds host complement component C3 as well as FH and interferes with innate immune recognition in a secret protein manner. S. suis 2 therefore appears to have developed a new strategy to combat host innate immunity and enhance survival in host blood.
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Affiliation(s)
- Xueqin Li
- From the State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071 and the Central Laboratory of Yijishan Hospital, Wannan Medical College, Wuhu 241001, China
| | - Peng Liu
- From the State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071 and
| | - Shuzhen Gan
- From the State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071 and
| | - Chunmao Zhang
- From the State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071 and
| | - Yuling Zheng
- From the State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071 and
| | - Yongqiang Jiang
- From the State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071 and
| | - Yuan Yuan
- From the State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071 and
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36
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Choline Binding Proteins from Streptococcus pneumoniae: A Dual Role as Enzybiotics and Targets for the Design of New Antimicrobials. Antibiotics (Basel) 2016; 5:antibiotics5020021. [PMID: 27314398 PMCID: PMC4929436 DOI: 10.3390/antibiotics5020021] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 05/04/2016] [Accepted: 05/16/2016] [Indexed: 12/20/2022] Open
Abstract
Streptococcus pneumoniae (pneumococcus) is an important pathogen responsible for acute invasive and non-invasive infections such as meningitis, sepsis and otitis media, being the major cause of community-acquired pneumonia. The fight against pneumococcus is currently hampered both by insufficient vaccine coverage and by rising antimicrobial resistances to traditional antibiotics, making necessary the research on novel targets. Choline binding proteins (CBPs) are a family of polypeptides found in pneumococcus and related species, as well as in some of their associated bacteriophages. They are characterized by a structural organization in two modules: a functional module (FM), and a choline-binding module (CBM) that anchors the protein to the choline residues present in the cell wall through non-covalent interactions. Pneumococcal CBPs include cell wall hydrolases, adhesins and other virulence factors, all playing relevant physiological roles for bacterial viability and virulence. Moreover, many pneumococcal phages also make use of hydrolytic CBPs to fulfill their infectivity cycle. Consequently, CBPs may play a dual role for the development of novel antipneumococcal drugs, both as targets for inhibitors of their binding to the cell wall and as active cell lytic agents (enzybiotics). In this article, we review the current state of knowledge about host- and phage-encoded pneumococcal CBPs, with a special focus on structural issues, together with their perspectives for effective anti-infectious treatments.
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Wong SM, Shaughnessy J, Ram S, Akerley BJ. Defining the Binding Region in Factor H to Develop a Therapeutic Factor H-Fc Fusion Protein against Non-Typeable Haemophilus influenzae. Front Cell Infect Microbiol 2016; 6:40. [PMID: 27148489 PMCID: PMC4829610 DOI: 10.3389/fcimb.2016.00040] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 03/21/2016] [Indexed: 11/13/2022] Open
Abstract
Non-typeable Haemophilus influenzae (NTHi) cause a range of illnesses including otitis media, sinusitis, and exacerbation of chronic obstructive pulmonary disease, infections that contribute to the problem of antibiotic resistance and are themselves often intractable to standard antibiotic treatment regimens. We investigated a strategy to exploit binding of the complement inhibitor Factor H (FH) to NTHi as a functional target for an immunotherapeutic containing the NTHi binding domain of FH fused to the Fc domain of IgG1. Chimeric proteins containing the regions that most FH-binding bacteria use to engage human FH, domains 6 and 7 (FH6,7/Fc) and/or 18 through 20 (FH18-20/Fc), were evaluated for binding to NTHi. FH6,7/Fc bound strongly to each of seven NTHi clinical isolates tested and efficiently promoted complement-mediated killing by normal human serum. FH18-20/Fc bound weakly to three of the strains but did not promote complement dependent killing. Outer-membrane protein P5 has been implicated in FH binding by NTHi, and FH6,7/Fc binding was greatly diminished in five of seven P5 deficient isogenic mutant strains tested, implicating an alternative FH binding protein in some strains. Binding of FH18-20/Fc was decreased in the P5 mutant of one strain. A murine model was used to evaluate potential therapeutic application of FH6,7/Fc. FH6,7/Fc efficiently promoted binding of C3 to NTHi exposed to mouse serum, and intranasal delivery of FH6,7/Fc resulted in significantly enhanced clearance of NTHi from the lung. Moreover, a P5 deficient mutant was attenuated for survival in the lung model, suggesting that escape mutants lacking P5 would be less likely to replace strains susceptible to FH6,7/Fc. These results provide evidence for the potential utility of FH6,7/Fc as a therapeutic against NTHi lung infection. FH binding is a common property of many respiratory tract pathogens and FH/Fc chimeras may represent promising alternative or adjunctive therapeutics against such infections, which are often polymicrobial.
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Affiliation(s)
- Sandy M Wong
- Department of Microbiology and Immunology, University of Mississippi Medical Center Jackson, MS, USA
| | - Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School Worcester, MA, USA
| | - Sanjay Ram
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School Worcester, MA, USA
| | - Brian J Akerley
- Department of Microbiology and Immunology, University of Mississippi Medical Center Jackson, MS, USA
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Salieb-Beugelaar GB, Zhang B, Nigo MM, Frischmann S, Hunziker PR. Improving diagnosis of pneumococcal disease by multiparameter testing and micro/nanotechnologies. EUROPEAN JOURNAL OF NANOMEDICINE 2016. [DOI: 10.1515/ejnm-2016-0012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
AbstractThe diagnosis and management of pneumococcal disease remains challenging, in particular in children who often are asymptomatic carriers, and in low-income countries with a high morbidity and mortality from febrile illnesses where the broad range of bacterial, viral and parasitic cases are in contrast to limited, diagnostic resources. Integration of multiple markers into a single, rapid test is desirable in such situations. Likewise, the development of multiparameter tests for relevant arrays of pathogens is important to avoid overtreatment of febrile syndromes with antibiotics. Miniaturization of tests through use of micro- and nanotechnologies combines several advantages: miniaturization reduces sample requirements, reduces the use of consumables and reagents leading to a reduction in costs, facilitates parallelization, enables point-of-care use of diagnostic equipment and even reduces the amount of potentially infectious disposables, characteristics that are highly desirable in most healthcare settings. This critical review emphasizes our vision on the importance of multiparametric testing for diagnosing pneumococcal infections in patients with fever and examines recent relevant developments in micro/nanotechnologies to achieve this goal.
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Glennie S, Gritzfeld JF, Pennington SH, Garner-Jones M, Coombes N, Hopkins MJ, Vadesilho CF, Miyaji EN, Wang D, Wright AD, Collins AM, Gordon SB, Ferreira DM. Modulation of nasopharyngeal innate defenses by viral coinfection predisposes individuals to experimental pneumococcal carriage. Mucosal Immunol 2016; 9:56-67. [PMID: 25921341 PMCID: PMC4703943 DOI: 10.1038/mi.2015.35] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 03/13/2015] [Indexed: 02/04/2023]
Abstract
Increased nasopharyngeal colonization density has been associated with pneumonia. We used experimental human pneumococcal carriage to investigate whether upper respiratory tract viral infection predisposes individuals to carriage. A total of 101 healthy subjects were screened for respiratory virus before pneumococcal intranasal challenge. Virus was associated with increased odds of colonization (75% virus positive became colonized vs. 46% virus-negative subjects; P=0.02). Nasal Factor H (FH) levels were increased in virus-positive subjects and were associated with increased colonization density. Using an in vitro epithelial model we explored the impact of increased mucosal FH in the context of coinfection. Epithelial inflammation and FH binding resulted in increased pneumococcal adherence to the epithelium. Binding was partially blocked by antibodies targeting the FH-binding protein Pneumococcal surface protein C (PspC). PspC epitope mapping revealed individuals lacked antibodies against the FH binding region. We propose that FH binding to PspC in vivo masks this binding site, enabling FH to facilitate pneumococcal/epithelial attachment during viral infection despite the presence of anti-PspC antibodies. We propose that a PspC-based vaccine lacking binding to FH could reduce pneumococcal colonization, and may have enhanced protection in those with underlying viral infection.
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Affiliation(s)
- S Glennie
- grid.48004.380000 0004 1936 9764Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, UK ,grid.5337.20000 0004 1936 7603Present Address: 7Present address: School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK., ,
| | - J F Gritzfeld
- grid.48004.380000 0004 1936 9764Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, UK
| | - S H Pennington
- grid.48004.380000 0004 1936 9764Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, UK
| | - M Garner-Jones
- grid.48004.380000 0004 1936 9764Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, UK
| | - N Coombes
- grid.48004.380000 0004 1936 9764Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, UK
| | - M J Hopkins
- grid.269741.f0000 0004 0421 1585Liverpool Specialist Virology Centre, Royal Liverpool and Broadgreen University Hospital, Liverpool, UK
| | - C F Vadesilho
- grid.418514.d0000 0001 1702 8585Centro de Biotecnologia, Instituto Butantan, Sao Paulo, Brazil
| | - E N Miyaji
- grid.418514.d0000 0001 1702 8585Centro de Biotecnologia, Instituto Butantan, Sao Paulo, Brazil
| | - D Wang
- grid.48004.380000 0004 1936 9764Tropical Clinical Trial Unit, Liverpool School of Tropical Medicine, Liverpool, UK
| | - A D Wright
- grid.48004.380000 0004 1936 9764Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, UK ,grid.269741.f0000 0004 0421 1585NIHR Royal Liverpool and Broadgreen University Hospital NHS Trust, Liverpool, UK
| | - A M Collins
- grid.48004.380000 0004 1936 9764Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, UK ,grid.269741.f0000 0004 0421 1585NIHR Royal Liverpool and Broadgreen University Hospital NHS Trust, Liverpool, UK
| | - S B Gordon
- grid.48004.380000 0004 1936 9764Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, UK
| | - D M Ferreira
- grid.48004.380000 0004 1936 9764Respiratory Infection Group, Liverpool School of Tropical Medicine, Liverpool, UK
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40
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Herbert AP, Makou E, Chen ZA, Kerr H, Richards A, Rappsilber J, Barlow PN. Complement Evasion Mediated by Enhancement of Captured Factor H: Implications for Protection of Self-Surfaces from Complement. THE JOURNAL OF IMMUNOLOGY 2015; 195:4986-98. [PMID: 26459349 PMCID: PMC4635569 DOI: 10.4049/jimmunol.1501388] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 09/10/2015] [Indexed: 12/12/2022]
Abstract
In an attempt to evade annihilation by the vertebrate complement system, many microbes capture factor H (FH), the key soluble complement-regulating protein in human plasma. However, FH is normally an active complement suppressor exclusively on self-surfaces and this selective action of FH is pivotal to self versus non-self discrimination by the complement system. We investigated whether the bacterially captured FH becomes functionally enhanced and, if so, how this is achieved at a structural level. We found, using site-directed and truncation mutagenesis, surface plasmon resonance, nuclear magnetic resonance spectroscopy, and cross-linking and mass spectrometry, that the N-terminal domain of Streptococcus pneumoniae protein PspC (PspCN) not only binds FH extraordinarily tightly but also holds it in a previously uncharacterized conformation. Functional enhancement arises from exposure of a C-terminal cryptic second binding site in FH for C3b, the activation-specific fragment of the pivotal complement component, C3. This conformational change of FH doubles its affinity for C3b and increases 5-fold its ability to accelerate decay of the binary enzyme (C3bBb) responsible for converting C3 to C3b in an amplification loop. Despite not sharing critical FH-binding residues, PspCNs from D39 and Tigr4 S. pneumoniae exhibit similar FH-anchoring and enhancing properties. We propose that these bacterial proteins mimic molecular markers of self-surfaces, providing a compelling hypothesis for how FH prevents complement-mediated injury to host tissue while lacking efficacy on virtually all other surfaces. In hemolysis assays with 2-aminoethylisothiouronium bromide–treated erythrocytes that recapitulate paroxysmal nocturnal hemoglobinuria, PspCN enhanced protection of cells by FH, suggesting a new paradigm for therapeutic complement suppression.
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Affiliation(s)
- Andrew P Herbert
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom
| | - Elisavet Makou
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom
| | - Zhuo A Chen
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom; and
| | - Heather Kerr
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom; Queen's Medical Research Institute, Edinburgh EH16 4TJ, United Kingdom
| | - Anna Richards
- Queen's Medical Research Institute, Edinburgh EH16 4TJ, United Kingdom
| | - Juri Rappsilber
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom; and
| | - Paul N Barlow
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom;
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41
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Domenech M, Ruiz S, Moscoso M, García E. In vitro biofilm development of Streptococcus pneumoniae and formation of choline-binding protein-DNA complexes. ENVIRONMENTAL MICROBIOLOGY REPORTS 2015; 7:715-727. [PMID: 25950767 DOI: 10.1111/1758-2229.12295] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 04/08/2015] [Indexed: 06/04/2023]
Abstract
Extracellular deoxyribonucleic acid (eDNA) is an essential component of bacterial biofilm matrices, and is required in their formation and maintenance. Extracellular DNA binds to exopolysaccharides or extracellular proteins, affording biofilms greater structural integrity. Recently, we reported evidence of intercellular eDNA-LytC complexes in pneumococcal biofilms. The LytC lysozyme is a member of the choline-binding family of proteins (CBPs) located on the pneumococcal surface. The present work shows that other CBPs, i.e. LytA, LytB, Pce, PspC and CbpF, which have a pI between 5 and 6, can bind DNA in vitro. This process requires the presence of divalent cations other than Mg(2+). This DNA binding capacity of CBPs appears to be independent of their enzymatic activity and, at least in the case of LytA, does not require the choline-binding domain characteristic of CBPs. Positively charged, surface-exposed, 25 amino acid-long peptides derived from the catalytic domain of LytB, were also found capable of DNA binding through electrostatic interactions. Confocal laser scanning microcopy revealed the existence of cell-associated LytB-eDNA complexes in Streptococcus pneumoniae biofilms. These and other findings suggest that these surface-located proteins of S. pneumoniae could play roles of varying importance in the colonization and/or invasion of human host where different environmental conditions exist.
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Affiliation(s)
- Mirian Domenech
- Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas (CIB-CSIC), Madrid, 28040, Spain
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Susana Ruiz
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Miriam Moscoso
- Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas (CIB-CSIC), Madrid, 28040, Spain
| | - Ernesto García
- Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas (CIB-CSIC), Madrid, 28040, Spain
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
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42
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Douam F, Gaska JM, Winer BY, Ding Q, von Schaewen M, Ploss A. Genetic Dissection of the Host Tropism of Human-Tropic Pathogens. Annu Rev Genet 2015; 49:21-45. [PMID: 26407032 DOI: 10.1146/annurev-genet-112414-054823] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Infectious diseases are the second leading cause of death worldwide. Although the host multitropism of some pathogens has rendered their manipulation possible in animal models, the human-restricted tropism of numerous viruses, bacteria, fungi, and parasites has seriously hampered our understanding of these pathogens. Hence, uncovering the genetic basis underlying the narrow tropism of such pathogens is critical for understanding their mechanisms of infection and pathogenesis. Moreover, such genetic dissection is essential for the generation of permissive animal models that can serve as critical tools for the development of therapeutics or vaccines against challenging human pathogens. In this review, we describe different experimental approaches utilized to uncover the genetic foundation regulating pathogen host tropism as well as their relevance for studying the tropism of several important human pathogens. Finally, we discuss the current and future uses of this knowledge for generating genetically modified animal models permissive for these pathogens.
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Affiliation(s)
- Florian Douam
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544; , , , , ,
| | - Jenna M Gaska
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544; , , , , ,
| | - Benjamin Y Winer
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544; , , , , ,
| | - Qiang Ding
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544; , , , , ,
| | - Markus von Schaewen
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544; , , , , ,
| | - Alexander Ploss
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544; , , , , ,
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43
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Multivalent Pneumococcal Protein Vaccines Comprising Pneumolysoid with Epitopes/Fragments of CbpA and/or PspA Elicit Strong and Broad Protection. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2015; 22:1079-89. [PMID: 26245351 DOI: 10.1128/cvi.00293-15] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 07/28/2015] [Indexed: 12/11/2022]
Abstract
Immunization with the pneumococcal proteins pneumolysin (Ply), choline binding protein A (CbpA), or pneumococcal surface protein A (PspA) elicits protective responses against invasive pneumococcal disease in animal models. In this study, we used different mouse models to test the efficacy of a variety of multivalent protein-based vaccines that comprised various combinations of full-length or peptide regions of the immunogens Ply, CbpA, or PspA: Ply toxoid with the L460D substitution (referred to herein as L460D); L460D fused with protective peptide epitopes from CbpA (YPT-L460D-NEEK [YLN]); L460D fused with the CD2 peptide containing the proline-rich region (PRR) of PspA (CD2-L460D); a combination of L460D and H70 (L460D+H70), a slightly larger PspA-derived peptide containing the PRR and the SM1 region; H70+YLN; and other combinations. Each mouse was immunized either intraperitoneally (i.p.) or subcutaneously (s.c.) with three doses (at 2-week intervals) of the various antigen combinations in alum adjuvant and then challenged in mouse models featuring different infection routes with multiple Streptococcus pneumoniae strains. In the i.p. infection sepsis model, H70+YLN consistently provided significant protection against three different challenge strains (serotypes 1, 2, and 6A); the CD2+YLN and H70+L460D combinations also elicited significant protection. Protection against intravenous (i.v.) sepsis (type 3 and 6A challenge strains) was largely dependent on PspA-derived antigen components, and the most protection was elicited by H70 with or without L460D or YLN. In a type 4 intratracheal (i.t.) challenge model that results in progression to meningitis, antigen combinations that contained YLN elicited the strongest protection. Thus, the trivalent antigen combination of H70+YLN elicited the strongest and broadest protection in diverse pneumococcal challenge models.
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44
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Mohan S, Hertweck C, Dudda A, Hammerschmidt S, Skerka C, Hallström T, Zipfel PF. Tuf of Streptococcus pneumoniae is a surface displayed human complement regulator binding protein. Mol Immunol 2014; 62:249-64. [PMID: 25046156 DOI: 10.1016/j.molimm.2014.06.029] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 06/21/2014] [Accepted: 06/23/2014] [Indexed: 11/15/2022]
Abstract
Streptococcus pneumoniae is a Gram-positive bacterium, causing acute sinusitis, otitis media, and severe diseases such as pneumonia, bacteraemia, meningitis and sepsis. Here we identify elongation factor Tu (Tuf) as a new Factor H binding protein of S. pneumoniae. The surface protein PspC which also binds a series of other human immune inhibitors, was the first identified pneumococcal Factor H binding protein of S. pneumoniae. Pneumococcal Tuf, a 55 kDa pneumococcal moonlighting protein which is displayed on the surface of pneumococci, is also located in the cytoplasm and is detected in the culture supernatant. Tuf binds the human complement inhibitors Factor H, FHL-1, CFHR1 and also the proenzyme plasminogen. Factor H and FHL-1 bound to Tuf, retain their complement regulatory activities. Similarly, plasminogen bound to Tuf was accessible for the activator uPA and activated plasmin cleaved the synthetic chromogenic substrate S-2251 as well as the natural substrates fibrinogen and the complement proteins C3 and C3b. Taken together, Tuf of S. pneumoniae is a new multi-functional bacterial virulence factor that helps the pathogen in complement escape and likely also in ECM degradation.
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Affiliation(s)
- Sarbani Mohan
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knöll-Institute, Jena, Germany
| | - Christian Hertweck
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knöll-Institute, Jena, Germany
| | - Antje Dudda
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knöll-Institute, Jena, Germany
| | - Sven Hammerschmidt
- Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, Ernst Moritz Arndt University, Greifswald, Germany
| | - Christine Skerka
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knöll-Institute, Jena, Germany
| | - Teresia Hallström
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knöll-Institute, Jena, Germany
| | - Peter F Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knöll-Institute, Jena, Germany; Faculty of Biology, Friedrich Schiller University, Jena, Germany.
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45
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Pleiotropic effects of cell wall amidase LytA on Streptococcus pneumoniae sensitivity to the host immune response. Infect Immun 2014; 83:591-603. [PMID: 25404032 DOI: 10.1128/iai.02811-14] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The complement system is a key component of the host immune response for the recognition and clearance of Streptococcus pneumoniae. In this study, we demonstrate that the amidase LytA, the main pneumococcal autolysin, inhibits complement-mediated immunity independently of effects on pneumolysin by a complex process of impaired complement activation, increased binding of complement regulators, and direct degradation of complement C3. The use of human sera depleted of either C1q or factor B confirmed that LytA prevented activation of both the classical and alternative pathways, whereas pneumolysin inhibited only the classical pathway. LytA prevented binding of C1q and the acute-phase protein C-reactive protein to S. pneumoniae, thereby reducing activation of the classical pathway on the bacterial surface. In addition, LytA increased recruitment of the complement downregulators C4BP and factor H to the pneumococcal cell wall and directly cleaved C3b and iC3b to generate degradation products. As a consequence, C3b deposition and phagocytosis increased in the absence of LytA and were markedly enhanced for the lytA ply double mutant, confirming that a combination of LytA and Ply is essential for the establishment of pneumococcal pneumonia and sepsis in a murine model of infection. These data demonstrate that LytA has pleiotropic effects on complement activation, a finding which, in combination with the effects of pneumolysin on complement to assist with pneumococcal complement evasion, confirms a major role of both proteins for the full virulence of the microorganism during septicemia.
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46
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Gilley RP, Orihuela CJ. Pneumococci in biofilms are non-invasive: implications on nasopharyngeal colonization. Front Cell Infect Microbiol 2014; 4:163. [PMID: 25414838 PMCID: PMC4222220 DOI: 10.3389/fcimb.2014.00163] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 10/21/2014] [Indexed: 11/21/2022] Open
Abstract
Streptococcus pneumoniae (the pneumococcus) is an opportunistic pathogen that colonizes the human nasopharynx asymptomatically. Invasive pneumococcal disease develops following bacterial aspiration into the lungs. Pneumococci within the nasopharynx exist as biofilms, a growth phenotype characterized by surface attachment, encasement within an extracellular matrix, and antimicrobial resistance. Experimental evidence indicates that biofilm pneumococci are attenuated vs. their planktonic counterpart. Biofilm pneumococci failed to cause invasive disease in experimentally challenged mice and in vitro were shown to be non-invasive despite being hyper-adhesive. This attenuated phenotype corresponds with observations that biofilm pneumococci elicit significantly less cytokine and chemokine production from host cells than their planktonic counterparts. Microarray and proteomic studies show that pneumococci within biofilms have decreased metabolism, less capsular polysaccharide, and reduced production of the pore-forming toxin pneumolysin. Biofilm pneumococci are predominately in the transparent phenotype, which has elevated cell wall phosphorylcholine, an adhesin subject to C-reactive protein mediated opsonization. Herein, we review these changes in virulence, interpret their impact on colonization and transmission, and discuss the notion that non-invasive biofilms are principal lifestyle of S. pneumoniae.
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Affiliation(s)
- Ryan P Gilley
- Department of Microbiology and Immunology, Center for Airway Inflammation Research, The University of Texas Health Science Center at San Antonio San Antonio, TX, USA
| | - Carlos J Orihuela
- Department of Microbiology and Immunology, Center for Airway Inflammation Research, The University of Texas Health Science Center at San Antonio San Antonio, TX, USA
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Schachern PA, Tsuprun V, Ferrieri P, Briles DE, Goetz S, Cureoglu S, Paparella MM, Juhn S. Pneumococcal PspA and PspC proteins: potential vaccine candidates for experimental otitis media. Int J Pediatr Otorhinolaryngol 2014; 78:1517-21. [PMID: 25015773 PMCID: PMC4129636 DOI: 10.1016/j.ijporl.2014.06.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 05/27/2014] [Accepted: 06/16/2014] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Otitis media is the most commonly diagnosed disease in ambulatory care and Streptococcuspneumoniae continues to be the most common bacterial agent. Bacterial resistance to antibiotics underscores the need for better vaccines. Current pneumococcal conjugate vaccines are modestly protective against otitis media; however, limited serotype coverage and serotype replacement have led to the investigation of pneumococcal proteins as potential vaccine candidates. Two proteins, pneumococcal surface proteins A (PspA) and C (PspC) are important virulence factors, expressed by virtually all strains. Although a number of pneumococcal proteins have been investigated in other infection sites, these proteins can have diverse organ-specific effects. In this study, we investigated the viability and virulence of single (PspA(-) and PspC(-)) and double (PspA(-)/PspC(-)) mutants of pneumococcal PspA and PspC proteins in the chinchilla middle ear. METHODS Bullae of 24 chinchillas were inoculated with 0.5 ml of 10(6) colony forming units (CFUs)/ml bacteria: 6 with wild-type D39 strain; 6 with PspA(-); 6 with PspC(-); and 6 with PspA(-)/PspC(-) isogenic mutant strains. Bacterial CFU levels in middle ear effusions and light microscopic analysis of the number of inflammatory cells in the round window membrane (RWM) were compared 48 h after inoculation. RESULTS At 48 h, CFUs in middle ears were increased for wild-type and PspC(-) strains compared to inoculum levels; however, they were significantly less for the group inoculated with the PspC(-) strain compared to wild-type strain. No bacteria were detected in the PspA(-) and PspA(-)/PspC(-) groups. The number of inflammatory cells in the RWM was significantly higher in wild-type compared to the PspA(-), PspC(-), and PspA(-)/PspC(-) groups. No significant difference in number of inflammatory cells was observed between any pairs of groups inoculated with mutant strains. CONCLUSION Viability and virulence of the PspC(-) strain were similar to the wild-type strain. The single PspA(-) and double PspA(-)/PspC(-) mutants were highly attenuated in the ear. Bacterial clearance of the PspA(-)/PspC(-) double mutant was indistinguishable from that of the PspA mutant. These studies provide no reason to exclude PspC from a multi-component protein vaccine containing PspA.
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Affiliation(s)
| | - Vladimir Tsuprun
- Departments of Otolaryngology, University of Minnesota, Minneapolis, MN, United States.
| | - Patricia Ferrieri
- Department of Pediatrics, University of Minnesota, Minneapolis, MN,Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN
| | - David E Briles
- Department of Microbiology, University of Alabama at Birmingham, AL
| | - Sarah Goetz
- Department of Pediatrics, University of Minnesota, Minneapolis, MN
| | | | | | - Steven Juhn
- Department of Otolaryngology, University of Minnesota, Minneapolis, MN
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Langereis JD, de Jonge MI, Weiser JN. Binding of human factor H to outer membrane protein P5 of non-typeable Haemophilus influenzae contributes to complement resistance. Mol Microbiol 2014; 94:89-106. [PMID: 25091181 DOI: 10.1111/mmi.12741] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/31/2014] [Indexed: 12/13/2022]
Abstract
Non-typeable Haemophilus influenzae is an opportunistic pathogen of the human upper respiratory tract and is often found to cause inflammatory diseases that include sinusitis, otitis media and exacerbations of chronic obstructive pulmonary disease. To persist in the inflammatory milieu during infection, non-typeable H. influenzae must resist the antimicrobial activity of the human complement system. Here, we used Tn-seq to identify genes important for resistance to complement-mediated killing. This screen identified outer membrane protein P5 in evasion of the alternative pathway of complement activation. Outer membrane protein P5 was shown to bind human complement regulatory protein factor H directly, thereby, preventing complement factor C3 deposition on the surface of the bacterium. Furthermore, we show that amino acid variation within surface-exposed regions within outer membrane P5 affected the level of factor H binding between individual strains.
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Affiliation(s)
- Jeroen D Langereis
- Department of Microbiology, University of Pennsylvania, Philadelphia, PA, USA; Department of Pediatrics, Laboratory of Pediatric Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
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Okumura CYM, Nizet V. Subterfuge and sabotage: evasion of host innate defenses by invasive gram-positive bacterial pathogens. Annu Rev Microbiol 2014; 68:439-58. [PMID: 25002085 DOI: 10.1146/annurev-micro-092412-155711] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The development of a severe invasive bacterial infection in an otherwise healthy individual is one of the most striking and fascinating aspects of human medicine. A small cadre of gram-positive pathogens of the genera Streptococcus and Staphylococcus stand out for their unique invasive disease potential and sophisticated ability to counteract the multifaceted components of human innate defense. This review illustrates how these leading human disease agents evade host complement deposition and activation, impede phagocyte recruitment and activation, resist the microbicidal activities of host antimicrobial peptides and reactive oxygen species, escape neutrophil extracellular traps, and promote and accelerate phagocyte cell death through the action of pore-forming cytolysins. Understanding the molecular basis of bacterial innate immune resistance can open new avenues for therapeutic intervention geared to disabling specific virulence factors and resensitizing the pathogen to host innate immune clearance.
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Affiliation(s)
- Cheryl Y M Okumura
- Department of Biology, Occidental College, Los Angeles, California 90041;
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50
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Mapping of epitopes recognized by antibodies induced by immunization of mice with PspA and PspC. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2014; 21:940-8. [PMID: 24807052 DOI: 10.1128/cvi.00239-14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Pneumococcal surface protein A (PspA) and pneumococcal surface protein C (PspC) are important candidates for an alternative vaccine against pneumococcal infections. Since these antigens show variability, the use of variants that do not afford broad protection may lead to the selection of vaccine escape bacteria. Epitopes capable of inducing antibodies with broad cross-reactivities should thus be the preferred antigens. In this work, experiments using peptide arrays show that most linear epitopes recognized by antibodies induced in mice against different PspAs were located at the initial 44 amino acids of the mature protein and that antibodies against these linear epitopes did not confer protection against a lethal challenge. Conversely, linear epitopes recognized by antibodies to PspC included the consensus sequences involved in the interaction with human factor H and secretory immunoglobulin A (sIgA). Since linear epitopes of PspA were not protective, larger overlapping fragments containing 100 amino acids of PspA of strain Rx1 were constructed (fragments 1 to 7, numbered from the N terminus) to permit the mapping of antibodies with conformational epitopes not represented in the peptide arrays. Antibodies from mice immunized with fragments 1, 2, 4, and 5 were capable of binding onto the surface of pneumococci and mediating protection against a lethal challenge. The fact that immunization of mice with 100-amino-acid fragments located at the more conserved N-terminal region of PspA (fragments 1 and 2) induced protection against a pneumococcal challenge indicates that the induction of antibodies against conformational epitopes present at this region may be important in strategies for inducing broad protection against pneumococci.
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