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Gil E, Noursadeghi M, Brown JS. Streptococcus pneumoniae interactions with the complement system. Front Cell Infect Microbiol 2022; 12:929483. [PMID: 35967850 PMCID: PMC9366601 DOI: 10.3389/fcimb.2022.929483] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 07/08/2022] [Indexed: 11/21/2022] Open
Abstract
Host innate and adaptive immunity to infection with Streptococcus pneumoniae is critically dependent on the complement system, demonstrated by the high incidence of invasive S. pneumoniae infection in people with inherited deficiency of complement components. The complement system is activated by S. pneumoniae through multiple mechanisms. The classical complement pathway is activated by recognition of S. pneumoniae by C-reactive protein, serum amyloid P, C1q, SIGN-R1, or natural or acquired antibody. Some S. pneumoniae strains are also recognised by ficolins to activate the mannose binding lectin (MBL) activation pathway. Complement activation is then amplified by the alternative complement pathway, which can also be activated by S. pneumoniae directly. Complement activation results in covalent linkage of the opsonic complement factors C3b and iC3b to the S. pneumoniae surface which promote phagocytic clearance, along with complement-mediated immune adherence to erythrocytes, thereby protecting against septicaemia. The role of complement for mucosal immunity to S. pneumoniae is less clear. Given the major role of complement in controlling infection with S. pneumoniae, it is perhaps unsurprising that S. pneumoniae has evolved multiple mechanisms of complement evasion, including the capsule, multiple surface proteins, and the toxin pneumolysin. There is considerable variation between S. pneumoniae capsular serotypes and genotypes with regards to sensitivity to complement which correlates with ability to cause invasive infections. However, at present we only have a limited understanding of the main mechanisms causing variations in complement sensitivity between S. pneumoniae strains and to non-pathogenic streptococci.
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Affiliation(s)
- Eliza Gil
- Division of Infection and Immunity, University College London, London, United Kingdom
- *Correspondence: Eliza Gil,
| | - Mahdad Noursadeghi
- Division of Infection and Immunity, University College London, London, United Kingdom
| | - Jeremy S. Brown
- Division of Medicine, University College London, London, United Kingdom
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2
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Pereira JM, Xu S, Leong JM, Sousa S. The Yin and Yang of Pneumolysin During Pneumococcal Infection. Front Immunol 2022; 13:878244. [PMID: 35529870 PMCID: PMC9074694 DOI: 10.3389/fimmu.2022.878244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 03/23/2022] [Indexed: 12/15/2022] Open
Abstract
Pneumolysin (PLY) is a pore-forming toxin produced by the human pathobiont Streptococcus pneumoniae, the major cause of pneumonia worldwide. PLY, a key pneumococcal virulence factor, can form transmembrane pores in host cells, disrupting plasma membrane integrity and deregulating cellular homeostasis. At lytic concentrations, PLY causes cell death. At sub-lytic concentrations, PLY triggers host cell survival pathways that cooperate to reseal the damaged plasma membrane and restore cell homeostasis. While PLY is generally considered a pivotal factor promoting S. pneumoniae colonization and survival, it is also a powerful trigger of the innate and adaptive host immune response against bacterial infection. The dichotomy of PLY as both a key bacterial virulence factor and a trigger for host immune modulation allows the toxin to display both "Yin" and "Yang" properties during infection, promoting disease by membrane perforation and activating inflammatory pathways, while also mitigating damage by triggering host cell repair and initiating anti-inflammatory responses. Due to its cytolytic activity and diverse immunomodulatory properties, PLY is integral to every stage of S. pneumoniae pathogenesis and may tip the balance towards either the pathogen or the host depending on the context of infection.
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Affiliation(s)
- Joana M. Pereira
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Molecular and Cellular (MC) Biology PhD Program, ICBAS - Instituto de Ciência Biomédicas Abel Salazar, University of Porto, Porto, Portugal
| | - Shuying Xu
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, United States
- Graduate Program in Immunology, Tufts Graduate School of Biomedical Sciences, Boston, MA, United States
| | - John M. Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, United States
| | - Sandra Sousa
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
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Scott NR, Mann B, Tuomanen EI, Orihuela CJ. Multi-Valent Protein Hybrid Pneumococcal Vaccines: A Strategy for the Next Generation of Vaccines. Vaccines (Basel) 2021; 9:209. [PMID: 33801372 PMCID: PMC8002124 DOI: 10.3390/vaccines9030209] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 02/23/2021] [Accepted: 02/25/2021] [Indexed: 12/15/2022] Open
Abstract
Streptococcus pneumoniae (Spn) is a bacterial pathogen known to colonize the upper respiratory tract and cause serious opportunistic diseases such as pneumonia, bacteremia, sepsis and meningitis. As a consequence, millions of attributable deaths occur annually, especially among infants, the elderly and immunocompromised individuals. Although current vaccines, composed of purified pneumococcal polysaccharide in free form or conjugated to a protein carrier, are widely used and have been demonstrated to be effective in target groups, Spn has continued to colonize and cause life-threatening disease in susceptible populations. This lack of broad protection highlights the necessity of improving upon the current "gold standard" pneumococcal vaccines to increase protection both by decreasing colonization and reducing the incidence of sterile-site infections. Over the past century, most of the pneumococcal proteins that play an essential role in colonization and pathogenesis have been identified and characterized. Some of these proteins have the potential to serve as antigens in a multi-valent protein vaccine that confers capsule independent protection. This review seeks to summarize the benefits and limitations of the currently employed vaccine strategies, describes how leading candidate proteins contribute to pneumococcal disease development, and discusses the potential of these proteins as protective antigens-including as a hybrid construct.
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Affiliation(s)
- Ninecia R. Scott
- Department of Microbiology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
| | - Beth Mann
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (B.M.); (E.I.T.)
| | - Elaine I. Tuomanen
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (B.M.); (E.I.T.)
| | - Carlos J. Orihuela
- Department of Microbiology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
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4
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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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5
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Bandara M, Skehel JM, Kadioglu A, Collinson I, Nobbs AH, Blocker AJ, Jenkinson HF. The accessory Sec system (SecY2A2) in Streptococcus pneumoniae is involved in export of pneumolysin toxin, adhesion and biofilm formation. Microbes Infect 2017; 19:402-412. [PMID: 28456649 PMCID: PMC5526788 DOI: 10.1016/j.micinf.2017.04.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 03/27/2017] [Accepted: 04/17/2017] [Indexed: 01/04/2023]
Abstract
In Streptococcus pneumoniae TIGR4, genes encoding a SecY2A2 accessory Sec system are present within a locus encoding a serine-rich repeat surface protein PsrP. Mutant strains deleted in secA2 or psrP were deficient in biofilm formation, while the ΔsecA2 mutant was reduced in binding to airway epithelial cells. Cell wall protein (CWP) fractions from the ΔsecA2 mutant, but not from the ΔpsrP mutant, were reduced in haemolytic (pneumolysin) activity. Contact-dependent pneumolysin (Ply) activity of wild type TIGR4 cells was ten-fold greater than that of ΔsecA2 mutant cells suggesting that Ply was not active at the ΔsecA2 cell surface. Ply protein was found to be present in the CWP fraction from the ΔsecA2 mutant, but showed aberrant electrophoretic migration indicative of protein modification. Proteomic analyses led to the discovery that the ΔsecA2 mutant CWP fraction was deficient in two glycosidases as well as other enzymes involved in carbohydrate metabolism. Taken collectively the results suggest that positioning of Ply into the cell wall compartment in active form, together with glycosyl hydrolases and adhesins, requires a functional accessory Sec system.
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Affiliation(s)
- Mikaila Bandara
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol, BS1 2LY, UK; School of Cellular & Molecular Medicine, University of Bristol, University Walk, Bristol, BS8 1TD, UK; School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - J Mark Skehel
- Biological Mass Spectrometry and Proteomics, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Aras Kadioglu
- Department of Clinical Infection, Microbiology & Immunology, Institute of Infection and Global Health, University of Liverpool, 8 West Derby Street, Liverpool L69 7BE, UK
| | - Ian Collinson
- School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Angela H Nobbs
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol, BS1 2LY, UK
| | - Ariel J Blocker
- School of Cellular & Molecular Medicine, University of Bristol, University Walk, Bristol, BS8 1TD, UK; School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, UK.
| | - Howard F Jenkinson
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol, BS1 2LY, UK.
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Tweten RK, Hotze EM, Wade KR. The Unique Molecular Choreography of Giant Pore Formation by the Cholesterol-Dependent Cytolysins of Gram-Positive Bacteria. Annu Rev Microbiol 2015; 69:323-40. [PMID: 26488276 PMCID: PMC7875328 DOI: 10.1146/annurev-micro-091014-104233] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The mechanism by which the cholesterol-dependent cytolysins (CDCs) assemble their giant β-barrel pore in cholesterol-rich membranes has been the subject of intense study in the past two decades. A combination of structural, biophysical, and biochemical analyses has revealed deep insights into the series of complex and highly choreographed secondary and tertiary structural transitions that the CDCs undergo to assemble their β-barrel pore in eukaryotic membranes. Our knowledge of the molecular details of these dramatic structural changes in CDCs has transformed our understanding of how giant pore complexes are assembled and has been critical to our understanding of the mechanisms of other important classes of pore-forming toxins and proteins across the kingdoms of life. Finally, there are tantalizing hints that the CDC pore-forming mechanism is more sophisticated than previously imagined and that some CDCs are employed in pore-independent processes.
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Affiliation(s)
- Rodney K Tweten
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104;
| | - Eileen M Hotze
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104;
| | - Kristin R Wade
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104;
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Los FCO, Randis TM, Aroian RV, Ratner AJ. Role of pore-forming toxins in bacterial infectious diseases. Microbiol Mol Biol Rev 2013; 77:173-207. [PMID: 23699254 PMCID: PMC3668673 DOI: 10.1128/mmbr.00052-12] [Citation(s) in RCA: 298] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Pore-forming toxins (PFTs) are the most common bacterial cytotoxic proteins and are required for virulence in a large number of important pathogens, including Streptococcus pneumoniae, group A and B streptococci, Staphylococcus aureus, Escherichia coli, and Mycobacterium tuberculosis. PFTs generally disrupt host cell membranes, but they can have additional effects independent of pore formation. Substantial effort has been devoted to understanding the molecular mechanisms underlying the functions of certain model PFTs. Likewise, specific host pathways mediating survival and immune responses in the face of toxin-mediated cellular damage have been delineated. However, less is known about the overall functions of PFTs during infection in vivo. This review focuses on common themes in the area of PFT biology, with an emphasis on studies addressing the roles of PFTs in in vivo and ex vivo models of colonization or infection. Common functions of PFTs include disruption of epithelial barrier function and evasion of host immune responses, which contribute to bacterial growth and spreading. The widespread nature of PFTs make this group of toxins an attractive target for the development of new virulence-targeted therapies that may have broad activity against human pathogens.
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Affiliation(s)
| | - Tara M. Randis
- Department of Pediatrics, Columbia University, New York, New York, USA
| | - Raffi V. Aroian
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California, USA
| | - Adam J. Ratner
- Department of Pediatrics, Columbia University, New York, New York, USA
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8
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Abstract
Streptococcus pneumoniae is a major causative agent of otitis media, pneumonia, bacteremia, and meningitis. Pneumolysin (Ply), a member of the cholesterol-dependent cytolysins (CDCs), is produced by virtually all clinical isolates of S. pneumoniae, and ply mutant strains are severely attenuated in mouse models of colonization and infection. In contrast to all other known members of the CDC family, Ply lacks a signal peptide for export outside the cell. Instead, Ply has been hypothesized to be released upon autolysis or, alternatively, via a nonautolytic mechanism that remains undefined. We show that an exogenously added signal sequence is not sufficient for Sec-dependent Ply secretion in S. pneumoniae but is sufficient in the surrogate host Bacillus subtilis. Previously, we showed that Ply is localized primarily to the cell wall compartment in the absence of detectable cell lysis. Here we show that Ply released by autolysis cannot reassociate with intact cells, suggesting that there is a Ply export mechanism that is coupled to cell wall localization of the protein. This putative export mechanism is capable of secreting a related CDC without its signal sequence. We show that B. subtilis can export Ply, suggesting that the export pathway is conserved. Finally, through truncation and domain swapping analyses, we show that export is dependent on domain 2 of Ply.
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9
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Hotze EM, Tweten RK. Membrane assembly of the cholesterol-dependent cytolysin pore complex. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1818:1028-38. [PMID: 21835159 PMCID: PMC3243806 DOI: 10.1016/j.bbamem.2011.07.036] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 07/24/2011] [Indexed: 12/16/2022]
Abstract
The cholesterol-dependent cytolysins (CDCs) are a large family of pore-forming toxins that are produced, secreted and contribute to the pathogenesis of many species of Gram-positive bacteria. The assembly of the CDC pore-forming complex has been under intense study for the past 20 years. These studies have revealed a molecular mechanism of pore formation that exhibits many novel features. The CDCs form large β-barrel pore complexes that are assembled from 35 to 40 soluble CDC monomers. Pore formation is dependent on the presence of membrane cholesterol, which functions as the receptor for most CDCs. Cholesterol binding initiates significant secondary and tertiary structural changes in the monomers, which lead to the assembly of a large membrane embedded β-barrel pore complex. This review will focus on the molecular mechanism of assembly of the CDC membrane pore complex and how these studies have led to insights into the mechanism of pore formation for other pore-forming proteins. This article is part of a Special Issue entitled: Protein Folding in Membranes.
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Affiliation(s)
- Eileen M. Hotze
- Department of Microbiology and Immunology, The University of Oklahoma Sciences Center, Oklahoma City, Oklahoma 73104, USA
| | - Rodney K. Tweten
- Department of Microbiology and Immunology, The University of Oklahoma Sciences Center, Oklahoma City, Oklahoma 73104, USA
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10
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Pneumolysin-induced CXCL8 production by nasopharyngeal epithelial cells is dependent on calcium flux and MAPK activation via Toll-like receptor 4. Microbes Infect 2010; 13:65-75. [PMID: 20974276 DOI: 10.1016/j.micinf.2010.10.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 09/29/2010] [Accepted: 10/04/2010] [Indexed: 11/22/2022]
Abstract
The natural niche of Streptococcus pneumoniae is the nasopharyngeal mucosa and nasopharyngeal carriage of pneumococci is widely prevalent. Pneumolysin (Ply), a pore-forming protein produced by S. pneumonia, may be important in driving the innate immune response of the nasopharynx. We studied the Ply-induced production of CXCL8 by nasopharyngeal cells and further analysed the mechanism of this induction. Detroit nasopharyngeal cells were stimulated with supernatants derived from bacterial cultures of Ply-deficient, wild-type pneumococci and recombinant Ply, and CXCL8 measured by ELISA. The role of MAP kinase family members in Ply-induced CXCL8 production was analysed using specific inhibitors, NF-κB activity was measured by immunoblot and Ply-mediated TLR4 activation analysed by a CXCL8 promotor luciferase assay. Ply significantly increased production of CXCL8 in Detroit and primary nasal cells. Flow cytometric analysis showed that Detroit cells express cell surface TLR4. CXCL8 production was dependent on changes in the intracellular Ca(2+) levels and also by NF-κB via activation of TLR4, and MAP kinase signalling. Ply induces production of CXCL8 by nasopharyngeal cells using signalling mechanisms involving Ca(2+) mobilisation and activation of MAPK and NF-κB via TLR4. This may be important in regulating nasopharyngeal immunity against pneumococcal colonization.
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11
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Immunization with a combination of three pneumococcal proteins confers additive and broad protection against Streptococcus pneumoniae Infections in Mice. Infect Immun 2009; 78:1276-83. [PMID: 20038538 DOI: 10.1128/iai.00473-09] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pneumococcal polysaccharide-based vaccines are effective in preventing pneumococcus infection; however, some drawbacks preclude their widespread use in developing and undeveloped countries. Here, we evaluated the protective effects of ATP-dependent caseinolytic protease (ClpP), pneumolysin mutant (DeltaA146 Ply), putative lipoate-protein ligase (Lpl), or combinations thereof against pneumococcal infections in mice. Vaccinated mice were intraperitoneally and/or intranasally challenged with different pneumococcal strains. In intraperitoneal challenge models with pneumococcal strain D39 (serotype 2), the most striking protection was obtained with the combination of the three antigens. Similarly, with the intranasal challenge models, (i) additive clearance of bacteria in lungs was observed for the combination of the three antigens and (ii) a combination vaccine conferred complete protection against intranasal infections of three of the four most common pneumococcal strains (serotypes 14, 19F, and 23F) and 80% protection for pneumococcal strain 6B. Even so, immunity to this combination could confer protection against pneumococcal infection with a mixture of four serotypes. Our results showed that the combination vaccine was as effective as the currently used vaccines (PCV7 and PPV23). These results indicate that system immunization with the combination of pneumococcal antigens could provide an additive and broad protection against Streptococcus pneumoniae in pneumonia and sepsis infection models.
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12
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Abstract
Streptococcus pneumoniae is the causative agent of multiple diseases, including otitis media, pneumonia, bacteremia, and meningitis. Pneumolysin (Ply), a member of the cholesterol-dependent cytolytic pore-forming toxins, is produced by virtually all clinical isolates of S. pneumoniae, and strains in which the Ply gene has been deleted are severely attenuated in mouse models of infection. In contrast to all other members of the cholesterol-dependent cytolysin family, Ply lacks a signal peptide for export. Instead, Ply has been hypothesized to be released upon autolysis or, alternatively, via a nonautolytic mechanism that remains ill defined. We determined by use of cell fractionation and Western blotting that, during in vitro growth, exported Ply is localized primarily to the cell wall compartment in 18 different serotypes in the absence of detectable cell lysis. Hemolytic assays revealed that this cell wall-localized Ply is active. Additionally, cell wall-localized Ply is accessible to extracellular protease and is detergent releasable.
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13
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Sonnen AFP, Rowe AJ, Andrew PW, Gilbert RJ. Oligomerisation of pneumolysin on cholesterol crystals: Similarities to the behaviour of polyene antibiotics. Toxicon 2008; 51:1554-9. [DOI: 10.1016/j.toxicon.2008.03.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2008] [Revised: 03/21/2008] [Accepted: 03/25/2008] [Indexed: 11/27/2022]
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14
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Sebert ME, Patel KP, Plotnick M, Weiser JN. Pneumococcal HtrA protease mediates inhibition of competence by the CiaRH two-component signaling system. J Bacteriol 2005; 187:3969-79. [PMID: 15937159 PMCID: PMC1151733 DOI: 10.1128/jb.187.12.3969-3979.2005] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Activation of the CiaRH two-component signaling system prevents the development of competence for genetic transformation in Streptococcus pneumoniae through a previously unknown mechanism. Earlier studies have shown that CiaRH controls the expression of htrA, which we show encodes a surface-expressed serine protease. We found that mutagenesis of the putative catalytic serine of HtrA, while not impacting the competence of a ciaRH+ strain, restored a normal competence profile to a strain having a mutation that constitutively activates the CiaH histidine kinase. This result implies that activity of HtrA is necessary for the CiaRH system to inhibit competence. Consistent with this finding, recombinant HtrA (rHtrA) decreased the competence of pneumococcal cultures. The rHtrA-mediated decline in transformation efficiency could not be corrected with excess competence-stimulating peptide (CSP), suggesting that HtrA does not act through degradation of this signaling molecule. The inhibitory effects of rHtrA and activated CiaH, however, were largely overcome in a strain having constitutive activation of the competence pathway through a mutation in the cytoplasmic domain of the ComD histidine kinase. Although these results suggested that HtrA might act through degradation of the extracellular portion of the ComD receptor, Western immunoblots for ComD did not reveal changes in protein levels attributable to HtrA. We therefore postulate that HtrA may act on an unknown protein target that potentiates the activation of the ComDE system by CSP. These findings suggest a novel regulatory role for pneumococcal HtrA in modulating the activity of a two-component signaling system that controls the development of genetic competence.
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Affiliation(s)
- M E Sebert
- Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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15
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Spreer A, Lis A, Gerber J, Reinert RR, Eiffert H, Nau R. Differences in clinical manifestation of Streptococcus pneumoniae infection are not correlated with in vitro production and release of the virulence factors pneumolysin and lipoteichoic and teichoic acids. J Clin Microbiol 2004; 42:3342-5. [PMID: 15243112 PMCID: PMC446287 DOI: 10.1128/jcm.42.7.3342-3345.2004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Production and release of the pneumococcal virulence factors pneumolysin and lipoteichoic and teichoic acid in 75 clinical isolates were investigated. No difference was found between strains causing systemic infection or localized respiratory infection and isolates from asymptomatic carriers. This suggests that the presence of pneumolysin and lipoteichoic and teichoic acid is a necessary but not a sufficient condition for pneumococcal infection and development of invasive disease.
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Affiliation(s)
- Annette Spreer
- Department of Neurology, University of Göttingen, Germany
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16
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Spreer A, Kerstan H, Böttcher T, Gerber J, Siemer A, Zysk G, Mitchell TJ, Eiffert H, Nau R. Reduced release of pneumolysin by Streptococcus pneumoniae in vitro and in vivo after treatment with nonbacteriolytic antibiotics in comparison to ceftriaxone. Antimicrob Agents Chemother 2003; 47:2649-54. [PMID: 12878534 PMCID: PMC166091 DOI: 10.1128/aac.47.8.2649-2654.2003] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pneumolysin, a virulence factor of Streptococcus pneumoniae with cytotoxic and proinflammatory activities, occurs at concentrations from 0.85 to 180 ng/ml in cerebrospinal fluid (CSF) of meningitis patients. In pneumococcal cultures and in a rabbit meningitis model, the concentrations of pneumolysin in supernatant and CSF were lower after addition of nonbacteriolytic bactericidal antibiotics (rifampin and clindamycin) than after incubation with ceftriaxone.
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Affiliation(s)
- Annette Spreer
- Department of Neurology, University of Göttingen, Göttingen, Germany
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17
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Jedrzejas MJ. Pneumococcal virulence factors: structure and function. Microbiol Mol Biol Rev 2001; 65:187-207 ; first page, table of contents. [PMID: 11381099 PMCID: PMC99024 DOI: 10.1128/mmbr.65.2.187-207.2001] [Citation(s) in RCA: 343] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The overall goal for this review is to summarize the current body of knowledge about the structure and function of major known antigens of Streptococcus pneumoniae, a major gram-positive bacterial pathogen of humans. This information is then related to the role of these proteins in pneumococcal pathogenesis and in the development of new vaccines and/or other antimicrobial agents. S. pneumoniae is the most common cause of fatal community-acquired pneumonia in the elderly and is also one of the most common causes of middle ear infections and meningitis in children. The present vaccine for the pneumococcus consists of a mixture of 23 different capsular polysaccharides. While this vaccine is very effective in young adults, who are normally at low risk of serious disease, it is only about 60% effective in the elderly. In children younger than 2 years the vaccine is ineffective and is not recommended due to the inability of this age group to mount an antibody response to the pneumococcal polysaccharides. Antimicrobial drugs such as penicillin have diminished the risk from pneumococcal disease. Several pneumococcal proteins including pneumococcal surface proteins A and C, hyaluronate lyase, pneumolysin, autolysin, pneumococcal surface antigen A, choline binding protein A, and two neuraminidase enzymes are being investigated as potential vaccine or drug targets. Essentially all of these antigens have been or are being investigated on a structural level in addition to being characterized biochemically. Recently, three-dimensional structures for hyaluronate lyase and pneumococcal surface antigen A became available from X-ray crystallography determinations. Also, modeling studies based on biophysical measurements provided more information about the structures of pneumolysin and pneumococcal surface protein A. Structural and biochemical studies of these pneumococcal virulence factors have facilitated the development of novel antibiotics or protein antigen-based vaccines as an alternative to polysaccharide-based vaccines for the treatment of pneumococcal disease.
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Affiliation(s)
- M J Jedrzejas
- Department of Microbiology, University of Alabama at Birmingham, 933 19th Street South, Birmingham, AL 35294.
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Balachandran P, Hollingshead SK, Paton JC, Briles DE. The autolytic enzyme LytA of Streptococcus pneumoniae is not responsible for releasing pneumolysin. J Bacteriol 2001; 183:3108-16. [PMID: 11325939 PMCID: PMC95211 DOI: 10.1128/jb.183.10.3108-3116.2001] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
It was previously proposed that autolysin's primary role in the virulence of pneumococci was to release pneumolysin to an extracellular location. This interpretation came into question when pneumolysin was observed to be released in significant amounts from some pneumococci during log-phase growth, because autolysis was not believed to occur at this time. We have reexamined this phenomenon in detail for one such strain, WU2. This study found that the extracellular release of pneumolysin from WU2 was not dependent on autolysin action. A mutant lacking autolysin showed the same pattern of pneumolysin release as the wild-type strain. Addition of mitomycin C to a growing WU2 culture did not induce lysis, indicating the absence of resident bacteriophages that could potentially harbor lytA-like genes. Furthermore, release of pneumolysin was unaltered by growth in 2% choline, a condition which is reported to inactivate autolysin, as well as most known pneumococcal phage lysins. Profiles of total proteins in the cytoplasm and in the supernatant media supported the hypothesis that release of pneumolysin is independent of pneumococcal lysis. Finally, under some infection conditions, mutations in pneumolysin and autolysin had different effects on virulence.
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Affiliation(s)
- P Balachandran
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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19
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Milohanic E, Jonquières R, Cossart P, Berche P, Gaillard JL. The autolysin Ami contributes to the adhesion of Listeria monocytogenes to eukaryotic cells via its cell wall anchor. Mol Microbiol 2001; 39:1212-24. [PMID: 11251838 DOI: 10.1111/j.1365-2958.2001.02208.x] [Citation(s) in RCA: 148] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Adherence of pathogenic microorganisms to the cell surface is a key event during infection. We have previously reported the characterization of Listeria monocytogenes transposon mutants defective in adhesion to eukaryotic cells. One of these mutants had lost the ability to produce Ami, a 102 kDa autolytic amidase with an N-terminal catalytic domain and a C-terminal cell wall-anchoring domain made up of repeated modules containing the dipeptide GW ('GW modules'). We generated ami null mutations by plasmid insertion into L. monocytogenes strains lacking the invasion proteins InlA (EGDDeltainlA), InlB (EGDDeltainlB) or both (EGDDeltainlAB). These mutants were 5-10 times less adherent than their parental strains in various cell types. The adhesion capacity of the mutants was restored by complementation with a DNA fragment encoding the Ami cell wall-anchoring domain fused to the Ami signal peptide. The cell-binding activity of the Ami cell wall-anchoring domain was further demonstrated using the purified polypeptide. Growth of the ami null mutants constructed in EGD and EGDDeltainlAB backgrounds was attenuated in the livers of mice inoculated intravenously, indicating a role for Ami in L. monocytogenes virulence. Adhesive properties have recently been reported in the non-catalytic domain of two other autolysins, Staphylococcus epidermidis AtlE and Staphylococcus saprophyticus Aas. Interestingly, we found that these domains were also composed of repeated GW modules. Thus, certain autolysins appear to promote bacterial attachment by means of their GW repeat domains. These molecules may contribute to the colonization of host tissues by Gram-positive bacteria.
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Affiliation(s)
- E Milohanic
- Laboratoire de Microbiologie, Institut National de la Santé et de la Recherche Médicale U 411, Faculté de Médecine Necker-Enfants Malades, 75730 Paris Cedex 15, France
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20
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Abstract
Previous studies led to the development of a model of contact-induced enhanced gonococcal invasion of human reproductive cells that utilizes the lutropin receptor (LHr) as both the induction signal for conversion to this enhanced-gonococcal-invasion phenotype (Inv(+) GC) and as the specific Inv(+) GC uptake mechanism. This model proposes that gonococci express a surface feature that mimics human chorionic gonadotropin (hCG), the cognate ligand for LHr, and that this structure is responsible for the specific and productive interaction of GC with LHr. In this report, we identify a 13-kDa gonococcal protein with immunological similarities to hCG. The antiserum reactivity is specific since interaction with the 13-kDa gonococcal protein can be blocked by the addition of highly purified hCG. This gonococcal "hCG-like" protein, purified from two-dimensional gels and by immunoprecipitation, was determined by N-terminal sequencing to be the ribosomal protein L12. We present evidence that gonococcal L12 is membrane associated and surface exposed in gonococci, as shown by immunoblot analysis of soluble and insoluble gonococcal protein and antibody adsorption studies with fixed GC. Using highly purified recombinant gonococcal L12, we show that preincubation of Inv(-) GC with micromolar amounts of rL12 leads to a subsequent five- to eightfold increase in invasion of the human endometrial cell line, Hec1B. In addition, nanomolar concentrations of exogenous L12 inhibits gonococcal invasion to approximately 70% of the level in controls. Thus, we propose a novel cellular location for the gonococcal ribosomal protein L12 and concomitant function in LHr-mediated gonococcal invasion of human reproductive cells.
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Affiliation(s)
- J M Spence
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
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21
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Whatmore AM, Dowson CG. The autolysin-encoding gene (lytA) of Streptococcus pneumoniae displays restricted allelic variation despite localized recombination events with genes of pneumococcal bacteriophage encoding cell wall lytic enzymes. Infect Immun 1999; 67:4551-6. [PMID: 10456899 PMCID: PMC96777 DOI: 10.1128/iai.67.9.4551-4556.1999] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The lytA-encoded autolysin (N-acetylmuramoyl-L-alanine amidase) of Streptococcus pneumoniae is believed to play an important role in the pathogenesis of pneumococcal infection and has been identified as a putative vaccine target. Allelic diversity of lytA in an extensive collection of clinical isolates was assessed by restriction fragment length polymorphism and confirmatory sequencing studies. Genetic diversity within lytA is limited, especially compared to the high levels of diversity seen in other pneumococcal virulence factor genes, although small blocks generating mosaic structure were identified. Sequence comparisons with genes encoding cell wall lytic enzymes of pneumococcal bacteriophage suggest that localized recombination events have occurred between host lytA and these bacteriophage genes. These results confirm earlier suggestions that recombination between DNA encoding bacteriophage autolytic enzymes and chromosomally encoded lytA might be important in the evolution of lytA. The implications of these findings for understanding the evolution of lytA and the potential utility of LytA as a vaccine target are discussed.
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Affiliation(s)
- A M Whatmore
- Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom.
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22
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Alexander JE, Berry AM, Paton JC, Rubins JB, Andrew PW, Mitchell TJ. Amino acid changes affecting the activity of pneumolysin alter the behaviour of pneumococci in pneumonia. Microb Pathog 1998; 24:167-74. [PMID: 9514638 DOI: 10.1006/mpat.1997.0185] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pneumolysin is a multi-functional toxin produced by Streptococcus pneumoniae. The toxin has distinct cytotoxic activity and complement-activating activity mediated by different parts of the toxin molecule. Mice challenged intranasally with a type 2 pneumococcal strain contract bronchopneumonia and bacteremia [1]. Mice were infected intranasally with isogenic mutants of this strain in which the chromosomal pneumolysin gene carried point mutations affecting either or both properties of pneumolysin. Reduction in either cytotoxic activity or complement activation by pneumolysin decreased the virulence of the mutant pneumococci. However, it was the ability to activate complement that most affected the behaviour of pneumococci in the lungs and associated bacteremia in the first 24 h following infection.
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Affiliation(s)
- J E Alexander
- Department of Microbiology and Immunology, University of Leicester, Leicester, LE1 9HN, U.K
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23
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Martín AC, López R, García P. Functional analysis of the two-gene lysis system of the pneumococcal phage Cp-1 in homologous and heterologous host cells. J Bacteriol 1998; 180:210-7. [PMID: 9440507 PMCID: PMC106873 DOI: 10.1128/jb.180.2.210-217.1998] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The two lysis genes cph1 and cpl1 of the Streptococcus pneumoniae bacteriophage Cp-1 coding for holin and lysozyme, respectively, have been cloned and expressed in Escherichia coli. Synthesis of the Cph1 holin resulted in bacterial cell death but not lysis. The cph1 gene was able to complement a lambda Sam mutation in the nonsuppressing E. coli HB101 strain to produce phage progeny, suggesting that the holins encoded by both phage genes have analogous functions and that the pneumococcal holin induces a nonspecific lesion in the cytoplasmic membrane. Concomitant expression of both holin and lysin of Cp-1 in E. coli resulted in cell lysis, apparently due to the ability of the Cpl1 lysozyme to hydrolyze the peptidoglycan layer of this bacterium. The functional analysis of the cph1 and cpl1 genes cloned in a pneumococcal mutant with a complete deletion of the lytA gene, which codes for the S. pneumoniae main autolysin, provided the first direct evidence that, in this gram-positive-bacterium system, the Cpl1 endolysin is released to its murein substrate through the activity of the Cph1 holin. Demonstration of holin function was achieved by proving the release of pneumolysin to the periplasmic fraction, which strongly suggested that the holin produces a lesion in the pneumococcal membrane.
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Affiliation(s)
- A C Martín
- Departamento de Microbiología Molecular, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
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24
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Virolainen A, Jero J, Käyhty H, Karma P, Eskola J, Leinonen M. Nasopharyngeal antibodies to pneumococcal pneumolysin in children with acute otitis media. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 1995; 2:704-7. [PMID: 8574834 PMCID: PMC170225 DOI: 10.1128/cdli.2.6.704-707.1995] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Pneumolysin, an intracellular protein toxin of all clinically relevant pneumococcal serotypes, is released in vivo during the autolysis of pneumococci and is believed to pave the way for intact pneumococci to invade and cause disease. Therefore, antibodies to pneumolysin should prevent its destructive function. We measured antibodies to pneumococcal pneumolysin in acute- and convalescent-phase nasopharyngeal aspirate samples of 120 children (median age, 2.5 years) with acute otitis media by enzyme immunoassay. Nasopharyngeal immunoglobulin M (IgM) and IgG class antibodies to pneumolysin were rarely detectable, whereas IgA class antibody was detected often, occurred independently of serum IgA antibody in serum, and correlated with the presence of the secretory component in pneumococcal antibody, indicating local production of IgA antibodies. Nasopharyngeal IgA antibody to pneumolysin was detected in 93% of the children already in the acute phase of otitis. Twenty percent of the children developed at least a threefold rise in the pneumolysin-specific IgA antibody concentration by the convalescent phase of otitis, with the youngest at 6 months of age, regardless of the pneumococcal findings in the nasopharynx or middle ear fluid. We suggest that nasopharyngeal IgA antibody to pneumolysin can be produced early in life by pneumococcal colonization.
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Affiliation(s)
- A Virolainen
- National Public Health Institute, Helsinki, Finland
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25
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Comis SD, Osborne MP, Stephen J, Tarlow MJ, Hayward TL, Mitchell TJ, Andrew PW, Boulnois GJ. Cytotoxic effects on hair cells of guinea pig cochlea produced by pneumolysin, the thiol activated toxin of Streptococcus pneumoniae. Acta Otolaryngol 1993; 113:152-9. [PMID: 8475728 DOI: 10.3109/00016489309135784] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The cytolytic toxin, pneumolysin, from the gram positive bacterium, Streptococcus pneumoniae, when perfused through the scala tympani of the guinea pig cochlea reduced the amplitude of both the compound action potential and the cochlear microphonic potential. When the surface of the organ of Corti was examined by scanning electron microscopy, both inner and outer hair cells and supporting cells were found to be damaged. Inner hair cells and outer hair cells of row 3 were the most susceptible to damage by pneumolysin, followed by row 2 and then by row 1 of the outer hair cells. Damage to hair cells included disruption and splaying of stereocilia, loss of stereocilia and complete dissolution of hair bundles. Apical surfaces of hair cells and supporting cells were torn, pitted and cratered with shrinkage and tearing of cell boundaries. Within the dose range perfused (0.05-1 micrograms/microliters in a 10 microliters aliquot), the magnitude of the physiological and anatomical lesions was concentration dependent. The cytotoxic effects of pneumolysin reported here may be clinically significant factors in deafness caused by meningitis and otitis media in humans.
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Affiliation(s)
- S D Comis
- Department of Physiology and Infection, Medical School, University of Birmingham, England
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26
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Johnson MK, Hobden JA, O'Callaghan RJ, Hill JM. Confirmation of the role of pneumolysin in ocular infections with Streptococcus pneumoniae. Curr Eye Res 1992; 11:1221-5. [PMID: 1490340 DOI: 10.3109/02713689208999547] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In earlier experiments on the role of the cytolytic toxin pneumolysin in ocular infections with pneumococcus, we found that a strain carrying a deletion in the gene encoding pneumolysin was considerably less virulent than wild type when tested in an intracorneal model of keratitis in the rabbit. To confirm this result, we have constructed a strain in which pneumolysin activity was restored by transformation of the deleted strain with a plasmid bearing the complete pneumolysin gene. Hemolytic titers of pneumolysin indicated that only one copy of the plasmid per bacterium expresses the pneumolysin gene in this strain. The virulence of this strain was compared with that of wild type and deleted strains transformed with the vector lacking the pneumolysin gene. Slit lamp examination (SLE) scores for eyes infected with the restored strain were similar to those for eyes infected with wild type and significantly greater than those for the pneumolysin-deleted strain. Molecular analysis of bacteria recovered from infected corneas showed that the vector plasmid was retained; however, in most isolates of the restored strain, the plasmid underwent an excision and lost the pneumolysin gene. The cloned gene apparently persisted long enough to induce the pathologic changes, and the results confirm the importance of pneumolysin as a virulence factor in ocular infections.
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Affiliation(s)
- M K Johnson
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA 70112
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27
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Berry AM, Paton JC, Hansman D. Effect of insertional inactivation of the genes encoding pneumolysin and autolysin on the virulence of Streptococcus pneumoniae type 3. Microb Pathog 1992; 12:87-93. [PMID: 1350046 DOI: 10.1016/0882-4010(92)90111-z] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Derivatives of Streptococcus pneumoniae type 3 deficient in production of either pneumolysin or autolysin were constructed. This was achieved by transformation of type 3 pneumococci with DNA from derivatives of a rough strain (Rx1), in which the respective genes had been interrupted by insertion-duplication mutagenesis using internal fragments of the cloned genes in the vector pVA891. Southern blot analysis confirmed that the pneumolysin or autolysin genes in the respective transformants had been interrupted by insertion of the plasmid-derived sequences. Both the pneumolysin-negative and the autolysin-negative strains had significantly reduced (P less than 0.0001) virulence in mice, as judged by survival time after intraperitoneal challenge. The median survival time of mice challenged with type 3 pneumococci in which either pneumolysin or autolysin production had been reconstituted by back-transformation of the mutants with an intact copy of the respective cloned gene (with concomitant elimination of plasmid-derived sequences), was indistinguishable from that of mice challenged with the wild-type strain. These results establish the importance of both pneumolysin and autolysin to the virulence of type 3 pneumococci.
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Affiliation(s)
- A M Berry
- Microbiology Department, Adelaide Children's Hospital, North Adelaide, Australia
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28
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Feldman C, Munro NC, Jeffery PK, Mitchell TJ, Andrew PW, Boulnois GJ, Guerreiro D, Rohde JA, Todd HC, Cole PJ. Pneumolysin induces the salient histologic features of pneumococcal infection in the rat lung in vivo. Am J Respir Cell Mol Biol 1991; 5:416-23. [PMID: 1834101 DOI: 10.1165/ajrcmb/5.5.416] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Streptococcus pneumoniae infections are common, but how they cause host tissue injury and death is incompletely understood. Immunization with pneumolysin, a thiol-activated toxin produced by the pneumococcus, partially protects animals during subsequent infection. The mechanism by which pneumolysin contributes to disease is not known. The aim of the present investigation was to determine the histologic changes induced by recombinant pneumolysin in the rat lung and to compare them with the changes induced by live organisms. Injection of either toxin (200 or 800 ng) or bacteria into the apical lobe bronchus was associated with the development of a severe lobar pneumonia restricted to the apical lobe. The changes induced by the toxin were greater at the higher concentration, and changes were most severe in those animals in which there was partial ligation of the apical lobe bronchus. The pneumonitis was less severe following injection of a modified toxin with decreased hemolytic activity, generated by site-directed mutagenesis of the cloned pneumolysin gene, indicating that this property of the toxin was important in generating pulmonary inflammation. There was still considerable pneumonitis after injection of a modified toxin with decreased capacity to activate complement.
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Affiliation(s)
- C Feldman
- Department of Thoracic Medicine, National Heart and Lung Institute, Brompton Hospital, London, United Kingdom
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29
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Johnson MK, Hobden JA, Hagenah M, O'Callaghan RJ, Hill JM, Chen S. The role of pneumolysin in ocular infections with Streptococcus pneumoniae. Curr Eye Res 1990; 9:1107-14. [PMID: 2095322 DOI: 10.3109/02713689008997584] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Pneumolysin, a cytolytic protein produced by Streptococcus pneumoniae, has many properties which suggest it may be an important virulence factor in pneumococcal ocular infections. To directly test this possibility, we have constructed pneumolysin-negative strains of S. pneumoniae and compared their virulence with that of the wild type in a rabbit model of intracorneal infection. A pneumolysin-negative strain produced by chemical mutagenesis (probably a point mutant) was found to be no less virulent than the parent strain. However, a strain bearing a deletion in the pneumolysin gene showed greatly reduced virulence. This strain produced less pathology while showing significantly higher bacterial counts. These results suggest that a property of the pneumolysin molecule other than its cytolytic (hemolytic) activity may be involved in its pathogenic mechanism of action. This property may be the ability to activate complement, known to be a function of pneumolysin, which results in influx of PMNs, reducing the bacterial counts but also producing tissue damage.
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Affiliation(s)
- M K Johnson
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA 70112
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30
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Pinkney M, Beachey E, Kehoe M. The thiol-activated toxin streptolysin O does not require a thiol group for cytolytic activity. Infect Immun 1989; 57:2553-8. [PMID: 2663727 PMCID: PMC313485 DOI: 10.1128/iai.57.8.2553-2558.1989] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Site-directed mutagenesis of the TGC codon in a cloned streptolysin O (SLO) gene exchanged the single Cys residue in SLO for either Ala or Ser. The parent wild-type SLO (SLO.Cys-530) and the SLO.Ala-530 and SLO.Ser-530 mutant toxins, expressed in Escherichia coli, were purified and analyzed. Wild-type SLO.Cys-530 and the SLO.Ala-530 mutant showed no significant differences in their specific hemolytic activities, while the SLO.Ser-530 mutant had a reduced (ca. 25%), but still considerable, specific hemolytic activity as compared with that of wild-type SLO. The parent and mutant toxins extracted from lysed erythrocyte membranes had similar sedimentation profiles on sucrose density gradients, suggesting that the mutations did not affect the ability of SLO to form oligomers in membranes. These results show that the widely held assumption that the in vitro cytolytic activity of SLO requires an essential Cys residue is not true.
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Affiliation(s)
- M Pinkney
- Department of Microbiology, Medical School, University of Newcastle upon Tyne, England
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31
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Lock RA, Paton JC, Hansman D. Purification and immunological characterization of neuraminidase produced by Streptococcus pneumoniae. Microb Pathog 1988; 4:33-43. [PMID: 3143891 DOI: 10.1016/0882-4010(88)90046-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Previous workers have suggested that Streptococcus pneumoniae, the pneumococcus, produces multiple forms of the enzyme neuraminidase. By serial chromatography on DEAE-cellulose, Sephacryl S-200, Amicon Red-A gel and hydroxylapatite we have purified to electrophoretic homogeneity a pneumococcal neuraminidase with an apparent molecular weight of 86,000 (as determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis). Mouse antiserum raised against the purified material reacted with a single species with molecular weight 107,000 (107K form) in crude pneumococcal cell lysate. During the purification procedure this species was progressively degraded to the molecular weight 86,000 (86K) form whilst retaining enzyme activity. Degradation of neuraminidase was inhibited by phenylmethylsulphonylfluoride (PMSF) and ethylenediaminetetraacetic acid (EDTA). Purification of the enzyme in the presence of these protease inhibitors permitted the isolation of the 107K species substantially undegraded and greater than 98% pure. Our findings on the degradation of neuraminidase during its purification account for previous reports of multiple neuraminidase isoenzymes in Streptococcus pneumoniae.
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Affiliation(s)
- R A Lock
- Department of Microbiology, Adelaide Children's Hospital, North Adelaide, South Australia
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32
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Kanclerski K, Möllby R. Production and purification of Streptococcus pneumoniae hemolysin (pneumolysin). J Clin Microbiol 1987; 25:222-5. [PMID: 3818918 PMCID: PMC265871 DOI: 10.1128/jcm.25.2.222-225.1987] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Pneumolysin was found to be produced by 112 of 113 clinical isolates of Streptococcus pneumoniae and to be an intracellular hemolysin. A 10-liter-scale fermentor production and purification procedure was developed for this hemolysin. The culture was concentrated by filtration 10 times before centrifugation. The cellular content was purified by ion-exchange chromatography, covalent thiopropyl gel chromatography, and gel filtration. One batch operation resulted in 6 mg of highly purified pneumolysin, with a yield of 66% and a specific activity of 1,400,000 hemolytic units per mg. The pneumolysin had a molecular weight of 53,000 and an isoelectric point of 5.2. The purification method developed will be of value in future studies on this hemolysin.
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33
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Paton JC, Lock RA, Hansman DJ. Effect of immunization with pneumolysin on survival time of mice challenged with Streptococcus pneumoniae. Infect Immun 1983; 40:548-52. [PMID: 6840851 PMCID: PMC264890 DOI: 10.1128/iai.40.2.548-552.1983] [Citation(s) in RCA: 148] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The role of the cytolytic toxin pneumolysin in the pathogenicity of Streptococcus pneumoniae was investigated. Pneumolysin was purified to homogeneity and used to immunize mice. When these mice were subsequently challenged via the nasal route with virulent S. pneumoniae, they survived significantly longer than control mice. The mean survival times were 5.52 and 2.48 days for immunized and control mice, respectively. This work provides direct evidence for the involvement of pneumolysin in pneumococcal pathogenicity.
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34
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Johnson MK, Hamon D, Drew GK. Isolation and characterization of pneumolysin-negative mutants of Streptococcus pneumoniae. Infect Immun 1982; 37:837-9. [PMID: 6922089 PMCID: PMC347608 DOI: 10.1128/iai.37.2.837-839.1982] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Pneumolysin-negative mutants of Streptococcus pneumoniae were isolated after mutagenesis with ethyl methane sulfonate. Though totally devoid of pneumolysin, these strains produced alpha hemolysis on blood agar when incubated aerobically. It is concluded that the alpha hemolysis typical of pneumococci is unrelated to their pneumolysin content.
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35
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Abstract
Pneumolysin, a cytolytic toxin from Streptococcus pneumoniae, has previously(1) been shown to interact in vitro with polymorphonuclear leukocytes in a variety of ways behaving as a chemotactic, lethal or lytic agent, depending on its concentration. In this study we examined the effect of leukopenia induced by administration of nitrogen mustard on the response of the rabbit to conjunctival instillation and intracorneal injection of pneumolysin. Control animals responded to instillation of crude and pure toxin with intense erythema and chemosis, and production of a thick discharge. No discharge and only traces of erythema and chemosis were noted in leukopenic animals. Leukopenic rabbits also showed a decreased capacity to respond to intracorneal injection of the toxin, particularly striking in the first 48 hours following pneumolysin injection, when opacification, discharge formation, chemosis, and erythema were found to be markedly less than in control animals. We conclude that the polymorphonuclear leukocyte plays a key role in the response of the rabbit eye to pneumococcal toxin. This system appears to be a good model for study of the inflammatory response to microbial products.
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