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Bessen DE, Beall BW, Hayes A, Huang W, DiChiara JM, Velusamy S, Tettelin H, Jolley KA, Fallon JT, Chochua S, Alobaidallah MSA, Higgs C, Barnett TC, Steemson JT, Proft T, Davies MR. Recombinational exchange of M-fibril and T-pilus genes generates extensive cell surface diversity in the global group A Streptococcus population. mBio 2024:e0069324. [PMID: 38587426 DOI: 10.1128/mbio.00693-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 03/18/2024] [Indexed: 04/09/2024] Open
Abstract
Among genes present in all group A streptococci (GAS), those encoding M-fibril and T-pilus proteins display the highest levels of sequence diversity, giving rise to the two primary serological typing schemes historically used to define strain. A new genotyping scheme for the pilin adhesin and backbone genes is developed and, when combined with emm typing, provides an account of the global GAS strain population. Cluster analysis based on nucleotide sequence similarity assigns most T-serotypes to discrete pilin backbone sequence clusters, yet the established T-types correspond to only half the clusters. The major pilin adhesin and backbone sequence clusters yield 98 unique combinations, defined as "pilin types." Numerous horizontal transfer events that involve pilin or emm genes generate extensive antigenic and functional diversity on the bacterial cell surface and lead to the emergence of new strains. Inferred pilin genotypes applied to a meta-analysis of global population-based collections of pharyngitis and impetigo isolates reveal highly significant associations between pilin genotypes and GAS infection at distinct ecological niches, consistent with a role for pilin gene products in adaptive evolution. Integration of emm and pilin typing into open-access online tools (pubmlst.org) ensures broad utility for end-users wanting to determine the architecture of M-fibril and T-pilus genes from genome assemblies.IMPORTANCEPrecision in defining the variant forms of infectious agents is critical to understanding their population biology and the epidemiology of associated diseases. Group A Streptococcus (GAS) is a global pathogen that causes a wide range of diseases and displays a highly diverse cell surface due to the antigenic heterogeneity of M-fibril and T-pilus proteins which also act as virulence factors of varied functions. emm genotyping is well-established and highly utilized, but there is no counterpart for pilin genes. A global GAS collection provides the basis for a comprehensive pilin typing scheme, and online tools for determining emm and pilin genotypes are developed. Application of these tools reveals the expansion of structural-functional diversity among GAS via horizontal gene transfer, as evidenced by unique combinations of surface protein genes. Pilin and emm genotype correlations with superficial throat vs skin infection provide new insights on the molecular determinants underlying key ecological and epidemiological trends.
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Affiliation(s)
- Debra E Bessen
- Department of Pathology, Microbiology, and Immunology, New York Medical College, Valhalla, New York, USA
| | - Bernard W Beall
- Respiratory Disease Branch, National Center for Immunizations and Respiratory Diseases, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, USA
- Eagle Global Scientific, LLC, Atlanta, Georgia, USA
| | - Andrew Hayes
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Weihua Huang
- Department of Pathology, Microbiology, and Immunology, New York Medical College, Valhalla, New York, USA
- Department of Pathology, Brody School of Medicine, Eastern Carolina University, Greenville, North Carolina, USA
| | - Jeanne M DiChiara
- Department of Pathology, Microbiology, and Immunology, New York Medical College, Valhalla, New York, USA
| | - Srinivasan Velusamy
- Respiratory Disease Branch, National Center for Immunizations and Respiratory Diseases, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, USA
| | - Hervé Tettelin
- Department of Microbiology and Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Keith A Jolley
- Department of Biology, University of Oxford, Oxford, United Kingdom
| | - John T Fallon
- Department of Pathology, Microbiology, and Immunology, New York Medical College, Valhalla, New York, USA
- Department of Pathology, Brody School of Medicine, Eastern Carolina University, Greenville, North Carolina, USA
| | - Sopio Chochua
- Respiratory Disease Branch, National Center for Immunizations and Respiratory Diseases, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, USA
| | - Mosaed S A Alobaidallah
- Department of Pathology, Microbiology, and Immunology, New York Medical College, Valhalla, New York, USA
| | - Charlie Higgs
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Timothy C Barnett
- The Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, University of Western Australia, Nedlands, Australia
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, Nedlands, Australia
| | - John T Steemson
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - Thomas Proft
- School of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
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2
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Takahashi R, J-Khemlani AH, Loh JMS, Radcliff FJ, Proft T, Tsai CJY. Different Group A Streptococcus pili lead to varying proinflammatory cytokine responses and virulence. Immunol Cell Biol 2024; 102:21-33. [PMID: 37795567 DOI: 10.1111/imcb.12692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 09/07/2023] [Accepted: 09/11/2023] [Indexed: 10/06/2023]
Abstract
The human pathogen Streptococcus pyogenes, or Group A Streptococcus (GAS), is associated with a variety of diseases ranging from mild skin and soft tissue infections to invasive diseases and immune sequelae such as rheumatic heart disease. We have recently reported that one of the virulence factors of this pathogen, the pilus, has inflammatory properties and strongly stimulates the innate immune system. Here we used a range of nonpathogenic Lactococcus lactis gain-of-function mutants, each expressing one of the major pilus types of GAS, to compare the immune responses generated by various types of fully assembled pili. In vitro assays indicated variability in the inflammatory response induced by different pili, with the fibronectin-binding, collagen-binding, T antigen (FCT)-1-type pilus from GAS serotype M6/T6 inducing significantly stronger cytokine secretion than other pili. Furthermore, we established that the same trend of pili-mediated immune response could be modeled in Galleria mellonella larvae, which possess a similar innate immune system to vertebrates. Counterintuitively, across the panel of pili types examined in this study, we observed a negative correlation between the intensity of the immune response demonstrated in our experiments and the disease severity observed clinically in the GAS strains associated with each pilus type. This observation suggests that pili-mediated inflammation is more likely to promote bacterial clearance instead of causing disruptive damages that intensify pathogenesis. This also indicates that pili may not be the main contributor to the inflammatory symptoms seen in GAS diseases. Rather, the immune-potentiating properties of the pilus components could potentially be exploited as a vaccine adjuvant.
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Affiliation(s)
- Risa Takahashi
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, New Zealand
| | - Adrina Hema J-Khemlani
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, New Zealand
| | - Jacelyn Mei San Loh
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Fiona Jane Radcliff
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Thomas Proft
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Catherine Jia-Yun Tsai
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
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3
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Loh JM, Aghababa H, Proft T. Eluding the immune system's frontline defense: Secreted complement evasion factors of pathogenic Gram-positive cocci. Microbiol Res 2023; 277:127512. [PMID: 37826985 DOI: 10.1016/j.micres.2023.127512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/01/2023] [Accepted: 10/04/2023] [Indexed: 10/14/2023]
Abstract
The human complement system is an important part of the innate immune response in the fight against invasive bacteria. Complement responses can be activated independently by the classical pathway, the lectin pathway, or the alternative pathway, each resulting in the formation of a C3 convertase that produces the anaphylatoxin C3a and the opsonin C3b by specifically cutting C3. Other important features of complement are the production of the chemotactic C5a peptide and the generation of the membrane attack complex to lyse intruding pathogens. Invasive pathogens like Staphylococcus aureus and several species of the genus Streptococcus have developed a variety of complement evasion strategies to resist complement activity thereby increasing their virulence and potential to cause disease. In this review, we focus on secreted complement evasion factors that assist the bacteria to avoid opsonization and terminal pathway lysis. We also briefly discuss the potential role of complement evasion factors for the development of vaccines and therapeutic interventions.
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Affiliation(s)
- Jacelyn Ms Loh
- Department of Molecular Medicine & Pathology, School of Medical Sciences, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - Haniyeh Aghababa
- Department of Molecular Medicine & Pathology, School of Medical Sciences, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Thomas Proft
- Department of Molecular Medicine & Pathology, School of Medical Sciences, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand.
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4
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Raynes JM, Young PG, Lorenz N, Loh JM, McGregor R, Baker EN, Proft T, Moreland NJ. Identification of an immunodominant region on a group A Streptococcus T-antigen reveals temperature-dependent motion in pili. Virulence 2023; 14:2180228. [PMID: 36809931 PMCID: PMC9980535 DOI: 10.1080/21505594.2023.2180228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
Group A Streptococcus (GAS) is a globally important pathogen causing a broad range of human diseases. GAS pili are elongated proteins with a backbone comprised repeating T-antigen subunits, which extend from the cell surface and have important roles in adhesion and establishing infection. No GAS vaccines are currently available, but T-antigen-based candidates are in pre-clinical development. This study investigated antibody-T-antigen interactions to gain molecular insight into functional antibody responses to GAS pili. Large, chimeric mouse/human Fab-phage libraries generated from mice vaccinated with the complete T18.1 pilus were screened against recombinant T18.1, a representative two-domain T-antigen. Of the two Fab identified for further characterization, one (designated E3) was cross-reactive and also recognized T3.2 and T13, while the other (H3) was type-specific reacting with only T18.1/T18.2 within a T-antigen panel representative of the major GAS T-types. The epitopes for the two Fab, determined by x-ray crystallography and peptide tiling, overlapped and mapped to the N-terminal region of the T18.1 N-domain. This region is predicted to be buried in the polymerized pilus by the C-domain of the next T-antigen subunit. However, flow cytometry and opsonophagocytic assays showed that these epitopes were accessible in the polymerized pilus at 37°C, though not at lower temperature. This suggests that there is motion within the pilus at physiological temperature, with structural analysis of a covalently linked T18.1 dimer indicating "knee-joint" like bending occurs between T-antigen subunits to expose this immunodominant region. This temperature dependent, mechanistic flexing provides new insight into how antibodies interact with T-antigens during infection.
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Affiliation(s)
- Jeremy M. Raynes
- School of Medical Sciences, The University of Auckland, Auckland, New Zealand,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Paul G. Young
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand,School of Biological Sciences, The University of Auckland, Auckland, New Zealand,CONTACT Paul G. Young
| | - Natalie Lorenz
- School of Medical Sciences, The University of Auckland, Auckland, New Zealand,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Jacelyn M.S. Loh
- School of Medical Sciences, The University of Auckland, Auckland, New Zealand,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Reuben McGregor
- School of Medical Sciences, The University of Auckland, Auckland, New Zealand,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Edward N. Baker
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand,School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - Thomas Proft
- School of Medical Sciences, The University of Auckland, Auckland, New Zealand,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Nicole J. Moreland
- School of Medical Sciences, The University of Auckland, Auckland, New Zealand,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand,Nicole J. Moreland
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5
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J-Khemlani AH, Pilapitiya D, Tsai CJY, Proft T, Loh JMS. Expanding strain coverage of a Group A Streptococcus pilus‐expressing
Lactococcus lactis
mucosal vaccine. Immunol Cell Biol 2023. [PMID: 36967611 DOI: 10.1111/imcb.12643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 10/31/2022] [Accepted: 03/26/2023] [Indexed: 03/29/2023]
Abstract
Group A Streptococcus (GAS) is a human pathogenic bacterium that can trigger a wide range of diseases, including the autoimmune diseases acute rheumatic fever and rheumatic heart disease, causing major morbidity and mortality in many low- and middle-income countries. Primary intervention programs have had limited success thus far, and a licensed vaccine has yet to be developed. The pilus of GAS is known to be involved in host cell adhesion, biofilm formation and immune evasion. We have a mucosal vaccine in development that expresses the pilus of GAS on the surface of the nonpathogenic bacterium Lactococcus lactis. To expand strain coverage, we combined seven L. lactis constructs, each expressing a different GAS pilus variant, and investigated the systemic and mucosal immune responses following immunization. Mice immunized with this combination showed specific immunoglobin G and immunoglobin A responses to the GAS pilus proteins of vaccine strains, at levels comparable to mice immunized with a single construct. Cross-reactivity to pilus proteins of nonvaccine strains was also evident. Furthermore, protective efficacy against a homologous strain of GAS in a murine nasopharyngeal colonization model was observed. Overall, this study provides further evidence for using pilus-expressing lactic acid bacteria as a vaccine to prevent upper respiratory tract GAS infections.
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Affiliation(s)
- Adrina Hema J-Khemlani
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Devaki Pilapitiya
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Catherine Jia-Yun Tsai
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Thomas Proft
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Jacelyn Mei San Loh
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland, New Zealand
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6
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Aghababa H, Loh JMS, Proft T. Methods to Analyze the Contribution of Complement Evasion Factor (CEF) to Streptococcus pyogenes Virulence. Methods Mol Biol 2023; 2674:119-129. [PMID: 37258964 DOI: 10.1007/978-1-0716-3243-7_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Group A Streptococcus (GAS, Streptococcus pyogenes) is an exclusively human pathogen that causes a range of diseases, including pharyngitis, tonsillitis, impetigo, erysipelas, necrotizing fasciitis, and toxic shock syndrome. Post-streptococcal sequelae include acute rheumatic fever and rheumatic heart disease. The bacterium produces a large arsenal of virulence factors that contribute to host tissue adhesion/colonization, bacterial spread, and host immune evasion. Immune evasion factors include proteins that interfere with complement, a system of plasma proteins that are activated by pathogens resulting in a variety of reactions on the surface of the pathogen. This leads to the activation of active components with a variety of effector functions, such as cell lysis, opsonization, and chemotaxis of phagocytes to the site of infection. We have recently identified a novel "complement evasion factor" (CEF) in S. pyogenes. CEF directly interacts with complement proteins C1r, C1s, C3, and C5, interrupts all three complement pathways, and prevents opsonization of the bacterial surface with C3b. We here present methods used to analyze the complement interference of CEF.
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Affiliation(s)
- Haniyeh Aghababa
- Department of Molecular Medicine & Pathology, School of Medical Sciences and Maurice Wilkins Centre for Biomolecular Discovery, The University of Auckland, Auckland, New Zealand
| | - Jacelyn M S Loh
- Department of Molecular Medicine & Pathology, School of Medical Sciences and Maurice Wilkins Centre for Biomolecular Discovery, The University of Auckland, Auckland, New Zealand
| | - Thomas Proft
- Department of Molecular Medicine & Pathology, School of Medical Sciences and Maurice Wilkins Centre for Biomolecular Discovery, The University of Auckland, Auckland, New Zealand.
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7
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Liu M, Svirskis D, Proft T, Loh J, Chen S, Kang D, Wen J. Exploring ex vivo peptideolysis of thymopentin and lipid-based nanocarriers towards oral formulations. Int J Pharm 2022; 625:122123. [PMID: 35995317 DOI: 10.1016/j.ijpharm.2022.122123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/27/2022] [Accepted: 08/14/2022] [Indexed: 01/20/2023]
Abstract
The oral delivery of medicines is the most popular route of administration for patients. However, thymopentin (TP5) is only available in the market in forms for parenteral administration. In large part, this is because of extensive peptidolytic degradation in the gastrointestinal tract (GIT), which decreases the amount of TP5 available for absorption. This study aims to understand the extent of TP5 peptideolysis and determine effective inhibitors and suitable lipid-based nanocarriers to aid in the development of an effective oral delivery formulation. Enzymatic degradation kinetics of TP5 was investigated in the presence or absence of mucosal and luminal components extracted from various parts of the rat intestine, including the duodenum, jejunum, ileum, and colon. Inhibition of TP5 enzymatic peptidolysis was screened in the presence or absence of EDTA, trypsin and chymotrypsin inhibitors from soybean (SBTCI), and bestatin. TP5 with SBTCI was loaded into lipid-based nanocarriers, including microemulsions, niosomes and solid lipid nanoparticles. These TP5-loaded nanocarriers were investigated through characterization of morphology, particle size, zeta potential, entrapment efficacy (EE%), and ex vivo rat intestinal degradation studies to select a lead formulation for a future oral drug delivery study. The degradation kinetics of TP5 followed pseudo-first-order kinetics, and the biological metabolism of TP5 was displayed in the presence of luminal contents, indicating that TP5 is sensitive to luminal enzymes. Notably, a considerable decrease in TP5 peptidolysis was found in the presence of SBTCI, bestatin, and EDTA. TP5 and SBTCI were loaded into three lipid-based delivery systems, displaying superior protection under ex vivo intestinal luminal contents and mucosal homogenates for 6 h compared with the pure drug solution. These findings suggest that using select inhibitors and lipid-based nanocarriers can decrease peptide degradation and may improve oral bioavailability of TP5 following oral administration.
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Affiliation(s)
- Mengyang Liu
- School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Darren Svirskis
- School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Thomas Proft
- Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Jacelyn Loh
- Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Shuo Chen
- School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Dali Kang
- School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Jingyuan Wen
- School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.
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8
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Takahashi R, Radcliff FJ, Proft T, Tsai CJ. Pilus proteins from
Streptococcus pyogenes
stimulate innate immune responses through Toll‐like receptor 2. Immunol Cell Biol 2022; 100:174-185. [PMID: 35124861 PMCID: PMC9303359 DOI: 10.1111/imcb.12523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/27/2022] [Accepted: 02/02/2022] [Indexed: 11/28/2022]
Abstract
The group A Streptococcus (GAS) pilus is a long, flexible, hair‐like structure anchored to the cell surface that facilitates the adherence of GAS to host cells, thus playing a critical role in initiating infections. Because of its important role in GAS virulence, the pilus has become an attractive target for vaccine development. While current research mainly focuses on pilus function and its potential as a vaccine component, there is a lack of knowledge on how the host immune system recognizes and responds to this abundant surface structure. Here we show that both assembled GAS pili and individual pilus proteins induce a potent release of the proinflammatory cytokines tumor necrosis factor and interleukin‐8. We further show that the surface‐exposed backbone pilin and ancillary pilin 1 subunits are Toll‐like receptor 2 (TLR2) agonists. Using reporter cell lines coexpressing human TLR2 in combination with either TLR1 or TLR6, we determined that activation was mediated by the TLR2/TLR6 heterodimer. Finally, we used solid‐phase and flow cytometry binding assays to illustrate a direct interaction between the pilus subunits and TLR2. These results provide further support for the suitability of the pilus as a vaccine component and opens potential avenues for using GAS pili as an adjuvant or immune‐modulation agent.
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Affiliation(s)
- Risa Takahashi
- Department of Molecular Medicine and Pathology, School of Medical Sciences The University of Auckland Auckland New Zealand
| | - Fiona J Radcliff
- Department of Molecular Medicine and Pathology, School of Medical Sciences The University of Auckland Auckland New Zealand
- Maurice Wilkins Centre for Biomolecular Discoveries The University of Auckland Auckland New Zealand
| | - Thomas Proft
- Department of Molecular Medicine and Pathology, School of Medical Sciences The University of Auckland Auckland New Zealand
- Maurice Wilkins Centre for Biomolecular Discoveries The University of Auckland Auckland New Zealand
| | - Catherine J‐Y Tsai
- Department of Molecular Medicine and Pathology, School of Medical Sciences The University of Auckland Auckland New Zealand
- Maurice Wilkins Centre for Biomolecular Discoveries The University of Auckland Auckland New Zealand
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9
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Abstract
Streptococcus pyogenes, a leading human pathogen, is responsible for a wide range of diseases, including skin and soft tissue infections and severe invasive diseases. S. pyogenes produces a large arsenal of virulence factors, including several immune evasion factors. We have identified an open reading frame (spy0136) in the S. pyogenes SF370 genome encoding a protein of unknown function. Using recombinant Spy0136 in a pull-down assay with human plasma and ELISA, we have identified four complement proteins (C1r, C1s, C3, and C5) as binding partners. Treatment of the complement proteins with PNGase F abrogated binding to C1s, C3, and C5, indicating glycan-dependent interactions. rSpy0136 inhibited complement-mediated hemolysis and interfered with all three complement pathways in a Wieslab complement assay. Furthermore, rSpy0136 inhibited deposition of the C3b opsonin and the membrane attack complex (MAC) on the surface of S. pyogenes. We therefore named the previously unknown protein ‘complement evasion factor’ (CEF). An S. pyogenes Δspy0136/cef deletion mutant showed decreased virulence in an in-vitro whole blood killing assay and a Galleria mellonella (wax moth) infection model. Furthermore, an L. lactis spy0136/cef gain-of-function mutant showed increased survival during growth in whole human blood. Analysis of serum samples from patients with invasive S. pyogenes revealed Spy0136/CEF sero-conversion indicating expression during disease. In summary, we have identified a novel S. pyogenes immune evasion factor that binds to several complement proteins to interfere with complement function. This is the first example of a S. pyogenes virulence factor binding to several different target proteins via glycan-dependent interactions.
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Affiliation(s)
- Haniyeh Aghababa
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, New Zealand
| | - Yi Tian Ting
- School of Biological Sciences, the University of Auckland, Auckland, New Zealand
- Infection and Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Devaki Pilapitiya
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, New Zealand
- University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Jacelyn M.S. Loh
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Biomolecular Discoveries. The University of Auckland, Auckland, New Zealand
| | - Paul G. Young
- School of Biological Sciences, the University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Biomolecular Discoveries. The University of Auckland, Auckland, New Zealand
| | - Thomas Proft
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Biomolecular Discoveries. The University of Auckland, Auckland, New Zealand
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10
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Tsai CJY, Loh JMS, Proft T. PilVax: A Novel Platform for the Development of Mucosal Vaccines. Methods Mol Biol 2022; 2412:399-410. [PMID: 34918257 DOI: 10.1007/978-1-0716-1892-9_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Peptide vaccines offer an attractive strategy to induce highly specific immune responses while reducing potential side effects. However, peptides are often poorly immunogenic and unstable on their own, requiring the need for potentially toxic adjuvants or expensive chemical coupling. The novel peptide delivery platform PilVax utilizes the rigid pilus structure from Group A Streptococcus (GAS) to stabilize and amplify the peptide, and present it on the surface of the non-pathogenic food-grade bacterium Lactococcus lactis. Upon intranasal immunization, PilVax vaccines have proven to induce peptide-specific systemic and mucosal responses. PilVax provides an alternative method to develop mucosal vaccines that are inexpensive to produce and easy to administer.
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Affiliation(s)
- Catherine Jia-Yun Tsai
- Department of Molecular Medicine and Pathology, School of Medical Sciences and Maurice Wilkins Centre for Biomolecular Discovery, The University of Auckland, Auckland, New Zealand
| | - Jacelyn M S Loh
- Department of Molecular Medicine and Pathology, School of Medical Sciences and Maurice Wilkins Centre for Biomolecular Discovery, The University of Auckland, Auckland, New Zealand
| | - Thomas Proft
- Department of Molecular Medicine and Pathology, School of Medical Sciences and Maurice Wilkins Centre for Biomolecular Discovery, The University of Auckland, Auckland, New Zealand.
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11
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Whitcombe AL, Han F, McAlister SM, Kirkham LAS, Young PG, Ritchie SR, Atatoa Carr P, Proft T, Moreland NJ. An eight-plex immunoassay for Group A streptococcus serology and vaccine development. J Immunol Methods 2021; 500:113194. [PMID: 34801540 DOI: 10.1016/j.jim.2021.113194] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 11/11/2021] [Accepted: 11/15/2021] [Indexed: 11/17/2022]
Abstract
Group A Streptococcus (GAS) is a major human pathogen responsible for superficial infections through to life-threatening invasive disease and the autoimmune sequelae acute rheumatic fever (ARF). Despite a significant global economic and health burden, there is no licensed vaccine available to prevent GAS disease. Several pre-clinical vaccines that target conserved GAS antigens are in development. Assays that measure antigen-specific antibodies are essential for vaccine research. The aim of this study was to develop a multiplex beadbased immunoassay that can detect and quantify antibody responses to multiple GAS antigen targets in small volume blood samples. This builds on our existing triplex assay comprised of antigens used in clinical serology for the diagnosis of ARF (SLO, DNase B and SpnA). Five additional conserved putative GAS vaccine antigens (Spy0843, SCPA, SpyCEP, SpyAD and the Group A carbohydrate), were coupled to spectrally unique beads to form an 8-plex antigen panel. After optimisation of the assay protocol, standard curves were generated, and assessments of assay specificity, precision and reproducibility were conducted. A broad range of antibody (IgG) titres were able to be quickly and accurately quantified from a single serum dilution. Assay utility was assessed using a panel of 62 clinical samples including serum from adults with GAS bacteraemia and children with ARF. Circulating IgG to all eight antigens was elevated in patients with GAS disease (n = 23) compared to age-matched controls (n = 39) (P < 0.05). The feasibility of using dried blood samples to quantify antigen-specific IgG was also demonstrated. In summary, a robust and reproducible 8-plex assay has been developed that simultaneously quantifies IgG antibodies to GAS vaccine and diagnostic antigens.
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Affiliation(s)
- Alana L Whitcombe
- School of Medical Sciences, The University of Auckland, New Zealand; Maurice Wilkins Centre for Biodiscovery, The University of Auckland, New Zealand
| | - Franklin Han
- School of Medical Sciences, The University of Auckland, New Zealand
| | - Sonia M McAlister
- Wesfarmers Centre of Vaccines & Infectious Disease, Telethon Kids Institute, Perth, Western Australia, Australia; Division of Paediatrics, School of Medicine, The University of Western Australia, Perth, Western Australia, Australia
| | - Lea-Ann S Kirkham
- Wesfarmers Centre of Vaccines & Infectious Disease, Telethon Kids Institute, Perth, Western Australia, Australia; Centre for Child Health Research, University of Western Australia, Perth, Australia
| | - Paul G Young
- School of Biological Sciences, The University of Auckland, New Zealand
| | | | | | - Thomas Proft
- School of Medical Sciences, The University of Auckland, New Zealand; Maurice Wilkins Centre for Biodiscovery, The University of Auckland, New Zealand
| | - Nicole J Moreland
- School of Medical Sciences, The University of Auckland, New Zealand; Maurice Wilkins Centre for Biodiscovery, The University of Auckland, New Zealand.
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12
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Blanchett S, Tsai CJ, Sandford S, Loh JM, Huang L, Kirman JR, Proft T. Intranasal immunization with Ag85B peptide 25 displayed on Lactococcus lactis using the PilVax platform induces antigen-specific B- and T-cell responses. Immunol Cell Biol 2021; 99:767-781. [PMID: 33866609 DOI: 10.1111/imcb.12462] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 03/27/2021] [Accepted: 04/15/2021] [Indexed: 12/19/2022]
Abstract
Mycobacterium tuberculosis (Mtb) remains a global epidemic despite the widespread use of Bacillus Calmette-Guérin (BCG). Consequently, novel vaccines are required to facilitate a reduction in Mtb morbidity and mortality. PilVax is a peptide delivery strategy for the generation of highly specific mucosal immune responses and is based on the food-grade bacterium Lactococcus lactis that is used to express selected peptides engineered within the Streptococcus pyogenes M1T1 pilus, allowing for peptide amplification, stabilization and enhanced immunogenicity. In the present study, the dominant T-cell epitope from the Mtb protein Ag85B was genetically engineered into the pilus backbone subunit and expressed on the surface of L. lactis. Western blot and flow cytometry confirmed formation of pilus containing the peptide DNA sequence. B-cell responses in intranasally vaccinated mice were analyzed by ELISA while T-cell responses were analyzed by flow cytometry. Serum titers of peptide-specific immunoglobulin (Ig) G and IgA were detected, confirming that vaccination produced antibodies against the cognate peptide. Peptide-specific IgA was also detected across several mucosal sites sampled. Peptide-specific CD4+ T cells were detected at levels similar to those of mice immunized with BCG. PilVax immunization resulted in an unexpected increase in the numbers of CD3+ CD4- CD8- [double negative (DN)] T cells in the lungs of vaccinated mice. Analysis of cytokine production following stimulation with the cognate peptide showed the major cytokine producing cells to be CD4+ T cells and DN T cells. This study provides insight into the antibody and peptide-specific cellular immune responses generated by PilVax vaccination and demonstrates the suitability of this vaccine for conducting a protection study.
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Affiliation(s)
- Samuel Blanchett
- Department of Molecular Medicine and Pathology, School of Medical Sciences, The University of Auckland, Auckland, New Zealand
| | - Catherine Jy Tsai
- Department of Molecular Medicine and Pathology, School of Medical Sciences, The University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Biomolecular Discoveries, The University of Auckland, Auckland, New Zealand
| | - Sarah Sandford
- Department of Microbiology & Immunology, University of Otago, Dunedin, New Zealand
| | - Jacelyn Ms Loh
- Department of Molecular Medicine and Pathology, School of Medical Sciences, The University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Biomolecular Discoveries, The University of Auckland, Auckland, New Zealand
| | - Lucy Huang
- Department of Microbiology & Immunology, University of Otago, Dunedin, New Zealand
| | - Joanna R Kirman
- Maurice Wilkins Centre for Biomolecular Discoveries, The University of Auckland, Auckland, New Zealand.,Department of Microbiology & Immunology, University of Otago, Dunedin, New Zealand
| | - Thomas Proft
- Department of Molecular Medicine and Pathology, School of Medical Sciences, The University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Biomolecular Discoveries, The University of Auckland, Auckland, New Zealand
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13
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Loh JMS, Rivera-Hernandez T, McGregor R, Khemlani AHJ, Tay ML, Cork AJ, M Raynes J, Moreland NJ, Walker MJ, Proft T. A multivalent T-antigen-based vaccine for Group A Streptococcus. Sci Rep 2021; 11:4353. [PMID: 33623073 PMCID: PMC7902606 DOI: 10.1038/s41598-021-83673-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 01/19/2021] [Indexed: 11/23/2022] Open
Abstract
Pili of Group A Streptococcus (GAS) are surface-exposed structures involved in adhesion and colonisation of the host during infection. The major protein component of the GAS pilus is the T-antigen, which multimerises to form the pilus shaft. There are currently no licenced vaccines against GAS infections and the T-antigen represents an attractive target for vaccination. We have generated a multivalent vaccine called TeeVax1, a recombinant protein that consists of a fusion of six T-antigen domains. Vaccination with TeeVax1 produces opsonophagocytic antibodies in rabbits and confers protective efficacy in mice against invasive disease. Two further recombinant proteins, TeeVax2 and TeeVax3 were constructed to cover 12 additional T-antigens. Combining TeeVax1–3 produced a robust antibody response in rabbits that was cross-reactive to a full panel of 21 T-antigens, expected to provide over 95% vaccine coverage. These results demonstrate the potential for a T-antigen-based vaccine to prevent GAS infections.
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Affiliation(s)
- Jacelyn M S Loh
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand. .,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand.
| | - Tania Rivera-Hernandez
- Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia.,Cátedras CONACYT-Unidad de Investigación Médica en Inmunoquímica, Hospital de Especialidades del Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Reuben McGregor
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - Adrina Hema J Khemlani
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - Mei Lin Tay
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - Amanda J Cork
- Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia
| | - Jeremy M Raynes
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand.,Monash University, Clayton Campus, Melbourne, VIC, Australia
| | - Nicole J Moreland
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - Mark J Walker
- Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia
| | - Thomas Proft
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand. .,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand.
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14
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Soh KY, Loh JMS, Hall C, Proft T. Functional Analysis of Two Novel Streptococcus iniae Virulence Factors Using a Zebrafish Infection Model. Microorganisms 2020; 8:E1361. [PMID: 32899555 PMCID: PMC7564053 DOI: 10.3390/microorganisms8091361] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 08/31/2020] [Accepted: 09/03/2020] [Indexed: 12/30/2022] Open
Abstract
Streptococcus iniae is a major fish pathogen that contributes to large annual losses in the aquaculture industry, exceeding US$100 million. It is also reported to cause opportunistic infections in humans. We have recently identified two novel S. iniae virulence factors, an extracellular nuclease (SpnAi) and a secreted nucleotidase (S5nAi), and verified their predicted enzymatic activities using recombinant proteins. Here, we report the generation of green fluorescent S. iniae spnAi and s5nAi deletion mutants and their evaluation in a transgenic zebrafish infection model. Our results show nuclease and nucleotidase activities in S. iniae could be attributed to SpnAi and S5nAi, respectively. Consistent with this, larvae infected with the deletion mutants demonstrated enhanced survival and bacterial clearance, compared to those infected with wild-type (WT) S. iniae. Deletion of spnAi and s5nAi resulted in sustained recruitment of neutrophils and macrophages, respectively, to the site of infection. We also show that recombinant SpnAi is able to degrade neutrophil extracellular traps (NETs) isolated from zebrafish kidney tissue. Our results suggest that both enzymes play an important role in S. iniae immune evasion and might present potential targets for the development of therapeutic agents or vaccines.
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Affiliation(s)
- Kar Yan Soh
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland 1142, New Zealand; (K.Y.S.); (J.M.S.L.)
- Maurice Wilkins Centre for Biomolecular Discoveries, The University of Auckland, Auckland 1142, New Zealand
| | - Jacelyn Mei San Loh
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland 1142, New Zealand; (K.Y.S.); (J.M.S.L.)
- Maurice Wilkins Centre for Biomolecular Discoveries, The University of Auckland, Auckland 1142, New Zealand
| | - Christopher Hall
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland 1142, New Zealand; (K.Y.S.); (J.M.S.L.)
| | - Thomas Proft
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland 1142, New Zealand; (K.Y.S.); (J.M.S.L.)
- Maurice Wilkins Centre for Biomolecular Discoveries, The University of Auckland, Auckland 1142, New Zealand
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15
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Clow F, Peterken K, Pearson V, Proft T, Radcliff FJ. PilVax, a novel Lactococcus lactis-based mucosal vaccine platform, stimulates systemic and mucosal immune responses to Staphylococcus aureus. Immunol Cell Biol 2020; 98:369-381. [PMID: 32150301 DOI: 10.1111/imcb.12325] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 02/23/2020] [Accepted: 03/07/2020] [Indexed: 12/28/2022]
Abstract
Most pathogens initiate infection via the mucosa, therefore delivery of vaccines directly to the mucosa is likely to be advantageous for stimulating protective immunity at the site of entry. PilVax is a novel mucosal vaccine platform that harnesses Lactococcus lactis bacteria engineered to stably express multiple copies of vaccine peptide antigens within pili, hair-like structures which extend from the cell wall. This strategy elicited systemic and mucosal antibody responses to a model antigen after intranasal immunization, but has not been tested for its capacity to stimulate protective mucosal immunity. A well-characterized linear B-cell epitope, D3(22-33) , from the fibronectin-binding protein A of Staphylococcus aureus was successfully introduced into PilVax and delivered intranasally to mice. Specific antipeptide immunoglobulin (Ig) G and IgA antibodies were detected in the serum and respiratory mucosa of vaccinated mice. Responses to the major pilus backbone protein Spy0128 were also assessed; robust antibody responses to this antigen were generated both systemically and in the respiratory and intestinal mucosa. Mice were challenged intranasally with the mouse-adapted S. aureus JSNZ strain and the S. aureus load quantified 7 days after challenge. Unexpectedly, exposure to PilVax, irrespective of the presence of the peptide, resulted in a significant reduction in S. aureus load in both the intestine and nasal mucosa (both P < 0.05) when compared with unvaccinated control mice. The mechanism(s) of protection are unclear, but merit further investigation to determine whether PilVax is a suitable platform for delivery of vaccine candidate antigens to the mucosa.
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Affiliation(s)
- Fiona Clow
- Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Kelly Peterken
- Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Victoria Pearson
- Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Thomas Proft
- Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Fiona J Radcliff
- Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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16
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Soh KY, Loh JMS, Proft T. Cell wall-anchored 5'-nucleotidases in Gram-positive cocci. Mol Microbiol 2020; 113:691-698. [PMID: 31872460 DOI: 10.1111/mmi.14442] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 11/29/2022]
Abstract
5'-nucleotidases (5'-NTs) are enzymes that catalyze the hydrolysis of nucleoside monophosphates to produce nucleosides and phosphate. Since the identification of adenosine synthase A (AdsA) in Staphylococcus aureus in 2009, several other 5'-NTs have been discovered in Gram-positive cocci, mainly in streptococci. Despite some differences in substrate specificity, pH range and metal ion requirements, all characterized 5'-NTs use AMP and ADP, and in some cases ATP, to produce the immunosuppressive adenosine, which dampens pro-inflammatory immune responses. Several 5'-NTs are also able to use dAMP as substrate to generate deoxy-adenosine which is cytotoxic for macrophages. A synergy between 5'-NTs and exonucleases which are commonly expressed in Gram-positive cocci has been described, where the nucleases provide dAMP as a cleavage product from DNA. Some of these nucleases produce dAMP by degrading the DNA backbone of neutrophil extracellular traps (NETs) resulting in a "double hit" strategy of immune evasion. This Micro Review provides an overview of the biochemical properties of Gram-positive cell wall-anchored 5'-NTs and their role as virulence factors. A potential use of 5'-NTs for vaccine development is also briefly discussed.
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Affiliation(s)
- Kar Yan Soh
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Biomolecular Discoveries, The University of Auckland, Auckland, New Zealand
| | - Jacelyn M S Loh
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Biomolecular Discoveries, The University of Auckland, Auckland, New Zealand
| | - Thomas Proft
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Biomolecular Discoveries, The University of Auckland, Auckland, New Zealand
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17
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Abstract
The critical first step of Group A Streptococcus (GAS) pathogenesis is adhesion to the host pharyngeal and skin epithelial cell surfaces (Brouwer et al., FEBS Lett 590:3739-3757, 2016). Host-cell adhesion assays provide a straightforward model to study these host-pathogen interactions. Here, we describe the culturing of immortalized cell lines into monolayers to mimic host epithelia. Various GAS strains can then be added to study their adhesion properties. In addition, we describe the use of antibodies raised against the cell-surface components of GAS to study if these are able to neutralize the binding of GAS to the cell lines. This provides an indication if these cell-surface components are involved in adhesion and if antibodies generated against them function through neutralization.
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Affiliation(s)
- Adrina H J Khemlani
- Department of Molecular Medicine and Pathology, School of Medical Sciences and Maurice Wilkins Centre for Biomolecular Discovery, The University of Auckland, Auckland, New Zealand
| | - Thomas Proft
- Department of Molecular Medicine and Pathology, School of Medical Sciences and Maurice Wilkins Centre for Biomolecular Discovery, The University of Auckland, Auckland, New Zealand.
| | - Jacelyn M S Loh
- Department of Molecular Medicine and Pathology, School of Medical Sciences and Maurice Wilkins Centre for Biomolecular Discovery, The University of Auckland, Auckland, New Zealand.
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18
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Abstract
Group A Streptococcus (GAS) often exists as an asymptomatic colonizer of the upper respiratory tract in humans. Unsurprisingly, a high proportion of symptomatic infections caused by GAS include pharyngitis. While not usually life-threatening, these infections cause significant morbidity and economic burden/loss of productivity, and can have downstream life-threatening autoimmune consequences. Modeling asymptomatic colonization in animals is, therefore, a useful tool to dissect host-bacteria interactions and to evaluate efficacy of vaccines aimed at reducing the burden of carriage. Here we describe a mouse model of nasopharyngeal colonization using nasal challenge of susceptible mice and the evaluation of subsequent bacterial burden.
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Affiliation(s)
- Adrina H J Khemlani
- Department of Molecular Medicine and Pathology, School of Medical Sciences and Maurice Wilkins Centre for Biomolecular Discovery, The University of Auckland, Auckland, New Zealand
| | - Thomas Proft
- Department of Molecular Medicine and Pathology, School of Medical Sciences and Maurice Wilkins Centre for Biomolecular Discovery, The University of Auckland, Auckland, New Zealand.
| | - Jacelyn M S Loh
- Department of Molecular Medicine and Pathology, School of Medical Sciences and Maurice Wilkins Centre for Biomolecular Discovery, The University of Auckland, Auckland, New Zealand.
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19
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Radcliff FJ, Waldvogel-Thurlow S, Clow F, Mahadevan M, Johnston J, Li G, Proft T, Douglas RG, Fraser JD. Impact of Superantigen-Producing Bacteria on T Cells from Tonsillar Hyperplasia. Pathogens 2019; 8:pathogens8030090. [PMID: 31252586 PMCID: PMC6789895 DOI: 10.3390/pathogens8030090] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 06/23/2019] [Accepted: 06/24/2019] [Indexed: 02/07/2023] Open
Abstract
Staphylococcus aureus and Group A Streptococcus (GAS) are common occupants of the tonsils and many strains produce potent exotoxins (mitogens) that directly target T cells, which could be a driver for tonsillar hyperplasia. Tonsil tissues from 41 patients were tested for these bacteria in conjunction with profiling of B and T cells by flow cytometry. S. aureus and GAS were detected in tonsil tissue from 44% and 7%, respectively, of patients by bacteriological culture; immuno-histology showed bacteria in close proximity to both B and T lymphocytes. The presence of tonsillar S. aureus did not alter B or T cell populations, whereas peripheral blood mucosal-associated invariant T (MAIT) cells were significantly increased in S. aureus culture positive individuals (p < 0.006). Alterations of tonsil CD4+ TCR Vβ family members relative to peripheral blood were evident in 29 patients. Three patients had strong TCR Vβ skewing indicative of recent exposure to superantigens, their tonsils contained mitogenic bacteria, and supernatants from these bacteria were used to partially recapitulate the skewing profile in vitro, supporting the notion that superantigens can target tonsillar T cells in situ. Tonsils are a reservoir for superantigen-producing bacteria with the capacity to alter the composition and function of key immune cells.
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Affiliation(s)
- Fiona J Radcliff
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland 1023, New Zealand.
| | | | - Fiona Clow
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland 1023, New Zealand
| | - Murali Mahadevan
- Department of Surgery, University of Auckland, Auckland 1023, New Zealand
| | - James Johnston
- Department of Surgery, University of Auckland, Auckland 1023, New Zealand
| | - Gen Li
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland 1023, New Zealand
| | - Thomas Proft
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland 1023, New Zealand
| | - Richard G Douglas
- Department of Surgery, University of Auckland, Auckland 1023, New Zealand
| | - John D Fraser
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland 1023, New Zealand
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20
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Loh JMS, Lorenz N, Tsai CJY, Khemlani AHJ, Proft T. Publisher Correction: Mucosal vaccination with pili from Group A Streptococcus expressed on Lactococcus lactis generates protective immune responses. Sci Rep 2019; 9:6975. [PMID: 31043651 PMCID: PMC6494862 DOI: 10.1038/s41598-019-43123-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
- Jacelyn M S Loh
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, 1023, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, 1023, New Zealand
| | - Natalie Lorenz
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, 1023, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, 1023, New Zealand
| | - Catherine J-Y Tsai
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, 1023, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, 1023, New Zealand
| | - Adrina Hema J Khemlani
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, 1023, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, 1023, New Zealand
| | - Thomas Proft
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, 1023, New Zealand. .,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, 1023, New Zealand.
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21
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Soh KY, Loh JMS, Proft T. Orthologues of Streptococcus pyogenes nuclease A (SpnA) and Streptococcal 5'-nucleotidase A (S5nA) found in Streptococcus iniae. J Biochem 2018; 164:165-171. [PMID: 29659850 DOI: 10.1093/jb/mvy039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 03/27/2018] [Indexed: 02/06/2023] Open
Abstract
Streptococcus pyogenes nuclease A (SpnA) and streptococcal 5' nucleosidase A (S5nA) are two recently described virulence factors from the human pathogen S. pyogenes. In vitro studies have shown that SpnA is a nuclease that cleaves ssDNA and dsDNA, including the DNA backbone of neutrophil extracellular traps. S5nA was shown to hydrolyse AMP and ADP, but not ATP, to generate the immunomodulatory molecule adenosine. S5nA also generates the macrophage-toxic deoxyadenosine from dAMP. However, detailed in vivo studies of the two enzymes have been hampered by difficulties with using current animal models for this exclusive human pathogen. Here we report the identification of two novel enzymes from the fish pathogen Streptococcus iniae that show similarities to SpnA and S5nA in amino acid sequence, protein domain structure and biochemical properties. We propose that SpnAi and S5nAi are orthologues of the S. pyogenes enzymes, providing a rationale to analyse the in vivo function of the two enzymes using a S. iniae-zebrafish infection model.
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Affiliation(s)
- Kar Yan Soh
- Department of Molecular Medicine & Pathology, School of Medical Sciences
| | - Jacelyn Mei San Loh
- Department of Molecular Medicine & Pathology, School of Medical Sciences.,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Thomas Proft
- Department of Molecular Medicine & Pathology, School of Medical Sciences.,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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22
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Raynes JM, Young PG, Proft T, Williamson DA, Baker EN, Moreland NJ. Protein adhesins as vaccine antigens for Group A Streptococcus. Pathog Dis 2018; 76:4919728. [DOI: 10.1093/femspd/fty016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 03/01/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- J M Raynes
- School of Medical Sciences, The University of Auckland, 85 Park Road, Auckland 1023, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, 3A Symonds Street, Auckland 1010, New Zealand
| | - P G Young
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, 3A Symonds Street, Auckland 1010, New Zealand
- School of Biological Sciences, University of Auckland, 5 Symonds Street, Auckland 1010, New Zealand
| | - T Proft
- School of Medical Sciences, The University of Auckland, 85 Park Road, Auckland 1023, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, 3A Symonds Street, Auckland 1010, New Zealand
| | - D A Williamson
- Microbiological Diagnostic Unit Public Health Laboratory, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria 3000, Australia
| | - E N Baker
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, 3A Symonds Street, Auckland 1010, New Zealand
- School of Biological Sciences, University of Auckland, 5 Symonds Street, Auckland 1010, New Zealand
| | - N J Moreland
- School of Medical Sciences, The University of Auckland, 85 Park Road, Auckland 1023, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, 3A Symonds Street, Auckland 1010, New Zealand
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23
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Wagachchi D, Tsai JYC, Chalmers C, Blanchett S, Loh JMS, Proft T. PilVax - a novel peptide delivery platform for the development of mucosal vaccines. Sci Rep 2018; 8:2555. [PMID: 29416095 PMCID: PMC5803258 DOI: 10.1038/s41598-018-20863-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 01/25/2018] [Indexed: 02/02/2023] Open
Abstract
Peptide vaccines are an attractive strategy to engineer the induction of highly targeted immune responses and avoid potentially allergenic and/or reactogenic protein regions. However, peptides by themselves are often unstable and poorly immunogenic, necessitating the need for an adjuvant and a specialised delivery system. We have developed a novel peptide delivery platform (PilVax) that allows the presentation of a stabilised and highly amplified peptide as part of the group A streptococcus serotype M1 pilus structure (PilM1) on the surface of the non-pathogenic bacterium Lactococcus lactis. To show proof of concept, we have successfully inserted the model peptide Ova324–339 into 3 different loop regions of the backbone protein Spy0128, which resulted in the assembly of the pilus containing large numbers of peptide on the surface of L. lactis. Intranasal immunisation of mice with L. lactis PilM1-Ova generated measurable Ova-specific systemic and mucosal responses (IgA and IgG). Furthermore, we show that multiple peptides can be inserted into the PilVax platform and that peptides can also be incorporated into structurally similar, but antigenically different pilus structures. PilVax may be useful as a cost-effective platform for the development of peptide vaccines against a variety of important human pathogens.
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Affiliation(s)
- Dasun Wagachchi
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, 1023, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, 1023, New Zealand
| | - Jia-Yun C Tsai
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, 1023, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, 1023, New Zealand
| | - Callum Chalmers
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, 1023, New Zealand
| | - Sam Blanchett
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, 1023, New Zealand
| | - Jacelyn M S Loh
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, 1023, New Zealand. .,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, 1023, New Zealand.
| | - Thomas Proft
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Auckland, 1023, New Zealand. .,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, 1023, New Zealand.
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24
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Hanson-Manful P, Whitcombe AL, Young PG, Atatoa Carr PE, Bell A, Didsbury A, Mitchell EA, Dunbar PR, Proft T, Moreland NJ. The novel Group A Streptococcus antigen SpnA combined with bead-based immunoassay technology improves streptococcal serology for the diagnosis of acute rheumatic fever. J Infect 2017; 76:361-368. [PMID: 29269013 DOI: 10.1016/j.jinf.2017.12.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 11/27/2017] [Accepted: 12/12/2017] [Indexed: 01/01/2023]
Abstract
OBJECTIVES Streptococcal serology provides evidence of prior Group A Streptococcus (GAS) exposure, crucial to the diagnosis of acute rheumatic fever (ARF) and post-streptococcal glomerulonephritis. However, current tests, which measure anti-streptolysin-O and anti-DNaseB antibodies, are limited by false positives in GAS endemic settings, and incompatible methodology requiring the two tests to be run in parallel. The objective was to improve streptococcal serology by combining the novel GAS antigen, SpnA, with streptolysin-O and DNaseB in a contemporary, bead-based immunoassay. METHODS Recombinant streptolysin-O, DNAseB and SpnA were conjugated to polystyrene beads with unique fluorescence positions so antibody binding to all three antigens could be detected simultaneously by cytometric bead array. Multiplex assays were run on sera collected in three groups: ARF; ethnically matched healthy children; and healthy adults. RESULTS The ability of the antigens to detect a previous GAS exposure in ARF was assessed using the 80th centile of the healthy children group as cut-off (upper limit of normal). SpnA had the highest sensitivity at 88%, compared with 75% for streptolysin-O and 56% for DNaseB. CONCLUSIONS SpnA has favorable immunokinetics for streptococcal serology, and can be combined with anti-streptolysin-O and anti-DNaseB in a multiplex format to improve efficiency and accuracy.
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Affiliation(s)
- Paulina Hanson-Manful
- Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre for Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Alana L Whitcombe
- Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Paul G Young
- Maurice Wilkins Centre for Biodiscovery, University of Auckland, Auckland, New Zealand; School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand
| | - Polly E Atatoa Carr
- Waikato District Health Board, Hamilton, New Zealand; National Institute of Demographic and Economic Analysis, University of Waikato, Waikato, New Zealand
| | - Anita Bell
- Waikato District Health Board, Hamilton, New Zealand
| | - Alicia Didsbury
- Maurice Wilkins Centre for Biodiscovery, University of Auckland, Auckland, New Zealand; School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand
| | - Edwin A Mitchell
- Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - P Rod Dunbar
- Maurice Wilkins Centre for Biodiscovery, University of Auckland, Auckland, New Zealand; School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand
| | - Thomas Proft
- Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre for Biodiscovery, University of Auckland, Auckland, New Zealand.
| | - Nicole J Moreland
- Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre for Biodiscovery, University of Auckland, Auckland, New Zealand.
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25
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Loh J, Tsai JY, Proft T. The ability of Group A streptococcus to adhere to immortalized human skin versus throat cell lines does not reflect their predicted tissue tropism. Clin Microbiol Infect 2017; 23:677.e1-677.e3. [DOI: 10.1016/j.cmi.2017.03.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/22/2017] [Accepted: 03/14/2017] [Indexed: 12/01/2022]
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26
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Radcliff FJ, Clow F, Mahadevan M, Johnston J, Proft T, Douglas RG, Fraser JD. A potential role for staphylococcal and streptococcal superantigens in driving skewing of TCR Vβ subsets in tonsillar hyperplasia. Med Microbiol Immunol 2017; 206:337-346. [DOI: 10.1007/s00430-017-0510-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/02/2017] [Indexed: 11/29/2022]
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27
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Lorenz N, Loh JMS, Moreland NJ, Proft T. Development of a high-throughput opsonophagocytic assay for the determination of functional antibody activity against Streptococcus pyogenes using bioluminescence. J Microbiol Methods 2017; 134:58-61. [PMID: 28115206 DOI: 10.1016/j.mimet.2017.01.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 01/19/2017] [Accepted: 01/19/2017] [Indexed: 10/20/2022]
Abstract
The lack of standardised protocols for the assessment of functional antibodies has hindered Streptococcus pyogenes research and the development of vaccines. A robust, high throughput opsonophagocytic bactericidal assay to determine protective antibodies in human and rabbit serum has been developed that utilises bioluminescence as a rapid read out.
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Affiliation(s)
- Natalie Lorenz
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand; Maurice Wilkins Centre, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Jacelyn M S Loh
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand; Maurice Wilkins Centre, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
| | - Nicole J Moreland
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand; Maurice Wilkins Centre, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Thomas Proft
- Department of Molecular Medicine & Pathology, School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand; Maurice Wilkins Centre, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
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28
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Khan LB, Read HM, Ritchie SR, Proft T. Artificial Urine for Teaching Urinalysis Concepts and Diagnosis of Urinary Tract Infection in the Medical Microbiology Laboratory. J Microbiol Biol Educ 2017; 18:jmbe-18-46. [PMID: 28861143 PMCID: PMC5577974 DOI: 10.1128/jmbe.v18i2.1325] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 06/16/2017] [Indexed: 05/21/2023]
Abstract
Dipstick urinalysis is an informative, quick, cost-effective and non-invasive diagnostic tool that is useful in clinical practice for the diagnosis of urinary tract infections (UTIs), kidney diseases, and diabetes. We used dipstick urinalysis as a hands-on microbiology laboratory exercise to reinforce student learning about UTIs with a particular focus on cystitis, which is a common bacterial infection. To avoid exposure to potentially contaminated human urine samples, we prepared artificial urine using easily acquired and affordable ingredients, which allowed less-experienced students to perform urinalysis without the risk of exposure to pathogenic organisms and ensured reliable availability of the urine samples. This practical class taught medical students how to use urinalysis data in conjunction with medical history to diagnose diseases from urine samples and to determine a treatment plan for clinical scenarios.
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Affiliation(s)
- Latifa B. Khan
- Department of Molecular Medicine and Pathology, School of Medical Sciences, The University of Auckland, Auckland 1142, New Zealand
| | - Hannah M. Read
- Department of Molecular Medicine and Pathology, School of Medical Sciences, The University of Auckland, Auckland 1142, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1142, New Zealand
| | - Stephen R. Ritchie
- Department of Molecular Medicine and Pathology, School of Medical Sciences, The University of Auckland, Auckland 1142, New Zealand
- Corresponding authors. Mailing address: School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland 1142, New Zealand. Phone +64-9-373-7599. E-mails: ;
| | - Thomas Proft
- Department of Molecular Medicine and Pathology, School of Medical Sciences, The University of Auckland, Auckland 1142, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1142, New Zealand
- Corresponding authors. Mailing address: School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland 1142, New Zealand. Phone +64-9-373-7599. E-mails: ;
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29
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Tsai JYC, Loh JMS, Clow F, Lorenz N, Proft T. The Group A Streptococcus serotype M2 pilus plays a role in host cell adhesion and immune evasion. Mol Microbiol 2016; 103:282-298. [PMID: 27741558 DOI: 10.1111/mmi.13556] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2016] [Indexed: 01/22/2023]
Abstract
Group A Streptococcus (GAS), or Streptococcus pyogenes, is a human pathogen that causes diseases ranging from skin and soft tissue infections to severe invasive diseases, such as toxic shock syndrome. Each GAS strain carries a particular pilus type encoded in the variable fibronectin-binding, collagen-binding, T antigen (FCT) genomic region. Here, we describe the functional analysis of the serotype M2 pilus encoded in the FCT-6 region. We found that, in contrast to other investigated GAS pili, the ancillary pilin 1 lacks adhesive properties. Instead, the backbone pilin is important for host cell adhesion and binds several host factors, including fibronectin and fibrinogen. Using a panel of recombinant pilus proteins, GAS gene deletion mutants and Lactococcus lactis gain-of-function mutants we show that, unlike other GAS pili, the FCT-6 pilus also contributes to immune evasion. This was demonstrated by a delay in blood clotting, increased intracellular survival of the bacteria in macrophages, higher bacterial survival rates in human whole blood and greater virulence in a Galleria mellonella infection model in the presence of fully assembled FCT-6 pili.
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Affiliation(s)
- Jia-Yun C Tsai
- Department of Molecular Medicine & Pathology, School of Medical Sciences.,Maurice Wilkins Centre, The University of Auckland, Auckland, New Zealand
| | - Jacelyn M S Loh
- Department of Molecular Medicine & Pathology, School of Medical Sciences.,Maurice Wilkins Centre, The University of Auckland, Auckland, New Zealand
| | - Fiona Clow
- Department of Molecular Medicine & Pathology, School of Medical Sciences
| | - Natalie Lorenz
- Department of Molecular Medicine & Pathology, School of Medical Sciences
| | - Thomas Proft
- Department of Molecular Medicine & Pathology, School of Medical Sciences.,Maurice Wilkins Centre, The University of Auckland, Auckland, New Zealand
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30
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Raynes JM, Frost HRC, Williamson DA, Young PG, Baker EN, Steemson JD, Loh JM, Proft T, Dunbar PR, Atatoa Carr PE, Bell A, Moreland NJ. Serological Evidence of Immune Priming by Group A Streptococci in Patients with Acute Rheumatic Fever. Front Microbiol 2016; 7:1119. [PMID: 27499748 PMCID: PMC4957554 DOI: 10.3389/fmicb.2016.01119] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 07/05/2016] [Indexed: 01/08/2023] Open
Abstract
Acute rheumatic fever (ARF) is an autoimmune response to Group A Streptococcus (GAS) infection. Repeated GAS exposures are proposed to ‘prime’ the immune system for autoimmunity. This notion of immune-priming by multiple GAS infections was first postulated in the 1960s, but direct experimental evidence to support the hypothesis has been lacking. Here, we present novel methodology, based on antibody responses to GAS T-antigens, that enables previous GAS exposures to be mapped in patient sera. T-antigens are surface expressed, type specific antigens and GAS strains fall into 18 major clades or T-types. A panel of recombinant T-antigens was generated and immunoassays were performed in parallel with serum depletion experiments allowing type-specific T-antigen antibodies to be distinguished from cross-reactive antibodies. At least two distinct GAS exposures were detected in each of the ARF sera tested. Furthermore, no two sera had the same T-antigen reactivity profile suggesting that each patient was exposed to a unique series of GAS T-types prior to developing ARF. The methods have provided much-needed experimental evidence to substantiate the immune-priming hypothesis, and will facilitate further serological profiling studies that explore the multifaceted interactions between GAS and the host.
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Affiliation(s)
- Jeremy M Raynes
- School of Biological Sciences, University of AucklandAuckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of AucklandAuckland, New Zealand
| | - Hannah R C Frost
- School of Biological Sciences, University of Auckland Auckland, New Zealand
| | - Deborah A Williamson
- Maurice Wilkins Centre for Molecular Biodiscovery, University of AucklandAuckland, New Zealand; Institute of Environmental Science and ResearchWellington, New Zealand; The Peter Doherty Institute, University of MelbourneMelbourne, Australia
| | - Paul G Young
- School of Biological Sciences, University of AucklandAuckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of AucklandAuckland, New Zealand
| | - Edward N Baker
- School of Biological Sciences, University of AucklandAuckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of AucklandAuckland, New Zealand
| | - John D Steemson
- School of Biological Sciences, University of Auckland Auckland, New Zealand
| | - Jacelyn M Loh
- Maurice Wilkins Centre for Molecular Biodiscovery, University of AucklandAuckland, New Zealand; School of Medical Sciences, University of AucklandAuckland, New Zealand
| | - Thomas Proft
- Maurice Wilkins Centre for Molecular Biodiscovery, University of AucklandAuckland, New Zealand; School of Medical Sciences, University of AucklandAuckland, New Zealand
| | - P R Dunbar
- School of Biological Sciences, University of AucklandAuckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of AucklandAuckland, New Zealand
| | | | - Anita Bell
- Waikato District Health Board Hamilton, New Zealand
| | - Nicole J Moreland
- School of Biological Sciences, University of AucklandAuckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of AucklandAuckland, New Zealand
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31
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Abstract
Galleria mellonella (greater wax moth or honeycomb moth) has been introduced as an alternative model to study microbial infections. G. mellonella larvae can be easily and inexpensively obtained in large numbers and are simple to use as they don't require special lab equipment. There are no ethical constraints and their short life cycle makes them ideal for large-scale studies. Although insects lack an adaptive immune response, their innate immune response shows remarkable similarities with the immune response in vertebrates. This review gives a current update of what is known about the immune system of G. mellonella and provides an extensive overview of how G. mellonella is used to study the virulence of Gram-positive and Gram-negative bacteria. In addition, the use of G. mellonella to evaluate the efficacy of antimicrobial agents and experimental phage therapy are also discussed. The review concludes with a critical assessment of the current limitatons of G. mellonella infection models.
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Affiliation(s)
- Catherine Jia-Yun Tsai
- a Department of Molecular Medicine & Pathology , School of Medical Sciences, University of Auckland , Auckland , New Zealand.,b Maurice Wilkins Center, University of Auckland , Auckland , New Zealand
| | - Jacelyn Mei San Loh
- a Department of Molecular Medicine & Pathology , School of Medical Sciences, University of Auckland , Auckland , New Zealand.,b Maurice Wilkins Center, University of Auckland , Auckland , New Zealand
| | - Thomas Proft
- a Department of Molecular Medicine & Pathology , School of Medical Sciences, University of Auckland , Auckland , New Zealand.,b Maurice Wilkins Center, University of Auckland , Auckland , New Zealand
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32
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Zheng L, Khemlani A, Lorenz N, Loh JMS, Langley RJ, Proft T. Streptococcal 5'-Nucleotidase A (S5nA), a Novel Streptococcus pyogenes Virulence Factor That Facilitates Immune Evasion. J Biol Chem 2015; 290:31126-37. [PMID: 26527680 DOI: 10.1074/jbc.m115.677443] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Indexed: 01/10/2023] Open
Abstract
Streptococcus pyogenes is an important human pathogen that causes a wide range of diseases. Using bioinformatics analysis of the complete S. pyogenes strain SF370 genome, we have identified a novel S. pyogenes virulence factor, which we termed streptococcal 5'-nucleotidase A (S5nA). A recombinant form of S5nA hydrolyzed AMP and ADP, but not ATP, to generate the immunomodulatory molecule adenosine. Michaelis-Menten kinetics revealed a Km of 169 μm and a Vmax of 7550 nmol/mg/min for the substrate AMP. Furthermore, recombinant S5nA acted synergistically with S. pyogenes nuclease A to generate macrophage-toxic deoxyadenosine from DNA. The enzyme showed optimal activity between pH 5 and pH 6.5 and between 37 and 47 °C. Like other 5'-nucleotidases, S5nA requires divalent cations and was active in the presence of Mg(2+), Ca(2+), or Mn(2+). However, Zn(2+) inhibited the enzymatic activity. Structural modeling combined with mutational analysis revealed a highly conserved catalytic dyad as well as conserved substrate and cation-binding sites. Recombinant S5nA significantly increased the survival of the non-pathogenic bacterium Lactococcus lactis during a human whole blood killing assay in a dose-dependent manner, suggesting a role as an S. pyogenes virulence factor. In conclusion, we have identified a novel S. pyogenes enzyme with 5'-nucleotidase activity and immune evasion properties.
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Affiliation(s)
- Lisa Zheng
- From the Department of Molecular Medicine and Pathology, School of Medical Sciences, and
| | - Adrina Khemlani
- From the Department of Molecular Medicine and Pathology, School of Medical Sciences, and
| | - Natalie Lorenz
- From the Department of Molecular Medicine and Pathology, School of Medical Sciences, and the Maurice Wilkins Center, University of Auckland, Auckland, New Zealand
| | - Jacelyn M S Loh
- From the Department of Molecular Medicine and Pathology, School of Medical Sciences, and the Maurice Wilkins Center, University of Auckland, Auckland, New Zealand
| | - Ries J Langley
- From the Department of Molecular Medicine and Pathology, School of Medical Sciences, and the Maurice Wilkins Center, University of Auckland, Auckland, New Zealand
| | - Thomas Proft
- From the Department of Molecular Medicine and Pathology, School of Medical Sciences, and the Maurice Wilkins Center, University of Auckland, Auckland, New Zealand
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Loh JMS, Proft T. Stabilized plasmid-based system for bioluminescent labeling of multiple streptococcal species. Biotechnol Lett 2015; 38:139-43. [PMID: 26410784 DOI: 10.1007/s10529-015-1967-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 09/22/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVE To determine if multiple streptococcal species can be easily labeled for biophotonic imaging using a toxin-antitoxin stabilized reporter plasmid containing the native firefly luciferase gene, originally developed for use in Group A Streptococcus. RESULTS A number of streptococcal species including Group B Streptococcus, Group C Streptococcus, Group G Streptococcus, S. iniae, S. vestibularis, and S. salivarius were successfully transformed with the reporter plasmid. In absence of antibiotic selection, the plasmid had variable stability amongst the six strains. The expression of firefly luciferase was highest in Group B Streptococcus and S. iniae, as observed by the brightest signal and lowest detection limits in vitro. CONCLUSION Multiple streptococcal species can be easily transformed with our toxin-antitoxin stabilized bioluminescent reporter plasmid. However, this plasmid shows variable stability and signal in different species, restricting its use for certain applications.
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Affiliation(s)
- Jacelyn M S Loh
- Department of Molecular Medicine & Pathology, School of Medical Sciences and the Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.
| | - Thomas Proft
- Department of Molecular Medicine & Pathology, School of Medical Sciences and the Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.
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34
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Williamson DA, Morgan J, Hope V, Fraser JD, Moreland NJ, Proft T, Mackereth G, Lennon D, Baker MG, Carter PE. Increasing incidence of invasive group A streptococcus disease in New Zealand, 2002-2012: a national population-based study. J Infect 2014; 70:127-34. [PMID: 25246363 DOI: 10.1016/j.jinf.2014.09.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 09/04/2014] [Accepted: 09/06/2014] [Indexed: 10/24/2022]
Abstract
OBJECTIVES To analyse the incidence, demographics and molecular epidemiology of invasive group A streptococcal (GAS) disease in New Zealand between 2002 and 2012. METHODS Using laboratory-based surveillance data, invasive GAS isolates were identified from the Institute of Environmental Science and Research, New Zealand. Hospitalization and mortality data were obtained from the New Zealand Ministry of Health. Molecular typing was performed by sequence analysis of the emm gene. RESULTS The incidence of invasive GAS infections increased from 3.9 per 100,000 population in 2002 to 7.9 per 100,000 population (P < 0.001) in 2012. The incidence was highest in the over 75-year age group, and in Pacific peoples. There was temporal variation in emm types associated with invasive GAS disease, with emm1 being the overall predominant emm type. The diversity of emm types varied significantly according to ethnicity. Overall, 59% of GAS isolates were theoretically covered by an experimental M-protein vaccine. CONCLUSIONS Our study provides valuable data on the epidemiology of invasive GAS disease in New Zealand, and represents one of the few studies to assess such longitudinal data across an entire nation. The increase in invasive GAS disease is concerning, and reasons for this should be explored further.
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Affiliation(s)
- Deborah A Williamson
- Institute of Environmental Science and Research, Wellington, New Zealand; University of Auckland, Auckland, New Zealand.
| | - Julie Morgan
- Institute of Environmental Science and Research, Wellington, New Zealand
| | - Virginia Hope
- Institute of Environmental Science and Research, Wellington, New Zealand
| | | | | | | | - Graham Mackereth
- Institute of Environmental Science and Research, Wellington, New Zealand
| | - Diana Lennon
- Institute of Environmental Science and Research, Wellington, New Zealand
| | | | - Philip E Carter
- Institute of Environmental Science and Research, Wellington, New Zealand
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Steemson JD, Moreland NJ, Williamson D, Morgan J, Carter PE, Proft T. Survey of the bp/tee genes from clinical group A streptococcus isolates in New Zealand - implications for vaccine development. J Med Microbiol 2014; 63:1670-1678. [PMID: 25190737 DOI: 10.1099/jmm.0.080804-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Group A streptococcus (GAS) is responsible for a wide range of diseases ranging from superficial infections, such as pharyngitis and impetigo, to life-threatening diseases, such as toxic shock syndrome and acute rheumatic fever (ARF). GAS pili are hair-like extensions protruding from the cell surface and consist of highly immunogenic structural proteins: the backbone pilin (BP) and one or two accessory pilins (AP1 and AP2). The protease-resistant BP builds the pilus shaft and has been recognized as the T-antigen, which forms the basis of a major serological typing scheme that is often used as a supplement to M typing. A previous sequence analysis of the bp gene (tee gene) in 39 GAS isolates revealed 15 different bp/tee types. In this study, we sequenced the bp/tee gene from 100 GAS isolates obtained from patients with pharyngitis, ARF or invasive disease in New Zealand. We found 20 new bp/tee alleles and four new bp/tee types/subtypes. No association between bp/tee type and clinical outcome was observed. We confirmed earlier reports that the emm type and tee type are associated strongly, but we also found exceptions, where multiple tee types could be found in certain M/emm type strains, such as M/emm89. We also reported, for the first time, the existence of a chimeric bp/tee allele, which was assigned into a new subclade (bp/tee3.1). A strong sequence conservation of the bp/tee gene was observed within the individual bp/tee types/subtypes (>97 % sequence identity), as well as between historical and contemporary New Zealand and international GAS strains. This temporal and geographical sequence stability provided further evidence for the potential use of the BP/T-antigen as a vaccine target.
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Affiliation(s)
- John D Steemson
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.,School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Nicole J Moreland
- Maurice Wilkins Centre, University of Auckland, Auckland, New Zealand.,School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Deborah Williamson
- Institute of Environmental Science and Research, Wellington, New Zealand.,Maurice Wilkins Centre, University of Auckland, Auckland, New Zealand.,School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Julie Morgan
- Institute of Environmental Science and Research, Wellington, New Zealand
| | - Philip E Carter
- Institute of Environmental Science and Research, Wellington, New Zealand
| | - Thomas Proft
- Maurice Wilkins Centre, University of Auckland, Auckland, New Zealand.,School of Medical Sciences, University of Auckland, Auckland, New Zealand
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Young PG, Proft T, Harris PWR, Brimble MA, Baker EN. Structure and activity of Streptococcus pyogenes SipA: a signal peptidase-like protein essential for pilus polymerisation. PLoS One 2014; 9:e99135. [PMID: 24911348 PMCID: PMC4049620 DOI: 10.1371/journal.pone.0099135] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 05/10/2014] [Indexed: 11/18/2022] Open
Abstract
The pili expressed on the surface of the human pathogen Streptococcus pyogenes play an important role in host cell attachment, colonisation and pathogenesis. These pili are built from two or three components, an adhesin subunit at the tip, a major pilin that forms a polymeric shaft, and a basal pilin that is attached to the cell wall. Assembly is carried out by specific sortase (cysteine transpeptidase) enzyme. These components are encoded in a small gene cluster within the S. pyogenes genome, often together with another protein, SipA, whose function is unknown. We show through functional assays, carried out by expressing the S. pyogenes pilus components in Lactococcus lactis, SipA from the clinically important M1T1 strain is essential for pilus assembly, and that SipA function is likely to be conserved in all S. pyogenes. From the crystal structure of SipA we confirm that SipA belongs to the family of bacterial signal peptidases (SPases), which process the signal-peptides of secreted proteins. In contrast to a previous arm-swapped SipA dimer, this present structure shows that its principal domain closely resembles the catalytic domain of SPases and has a very similar peptide-binding cleft, but it lacks the catalytic Ser and Lys residues characteristic of SPases. In SipA these are replaced by Asp and Gly residues, which play no part in activity. We propose that SipA functions by binding a key component at the bacterial cell surface, in a conformation that facilitates pilus assembly.
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Affiliation(s)
- Paul G. Young
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Thomas Proft
- Department of Molecular Medicine, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Paul W. R. Harris
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Margaret A. Brimble
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Edward N. Baker
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
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Moreland NJ, Waddington CS, Williamson DA, Sriskandan S, Smeesters PR, Proft T, Steer AC, Walker MJ, Baker EN, Baker MG, Lennon D, Dunbar R, Carapetis J, Fraser JD. Working towards a Group A Streptococcal vaccine: Report of a collaborative Trans-Tasman workshop. Vaccine 2014; 32:3713-20. [DOI: 10.1016/j.vaccine.2014.05.017] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Accepted: 05/01/2014] [Indexed: 11/25/2022]
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Williamson DA, Moreland NJ, Carter P, Upton A, Morgan J, Proft T, Lennon D, Baker MG, Dunbar R, Fraser JD. Molecular epidemiology of group A streptococcus from pharyngeal isolates in Auckland, New Zealand, 2013. N Z Med J 2014; 127:55-60. [PMID: 24481387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
AIMS To describe the molecular epidemiology of emm types associated with circulating pharyngeal group A streptococcus (GAS) isolates in Auckland, New Zealand. METHODS GAS isolates were collected over a 10-day period from a community pathology provider in Auckland. PCR analysis and sequencing of the emm gene was performed at the Institute of Environmental Science and Research. RESULTS A total of 52 emm types were identified from 278 GAS isolates. The three most common emm types were emm1, emm89 and emm12. Overall, the experimental 30-valent GAS M protein vaccine covered 19 / 52 (37%) of emm types in our study. DISCUSSION Our study provides baseline data on the circulating pharyngeal GAS emm types in Auckland. Future clinical and molecular surveillance of GAS pharyngitis is essential in the context of ongoing GAS vaccine development.
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Affiliation(s)
- Deborah A Williamson
- Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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Loh JMS, Proft T. Comparison of firefly luciferase and NanoLuc luciferase for biophotonic labeling of group A Streptococcus. Biotechnol Lett 2013; 36:829-34. [DOI: 10.1007/s10529-013-1423-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 11/18/2013] [Indexed: 02/02/2023]
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Loh JMS, Proft T. Toxin-antitoxin-stabilized reporter plasmids for biophotonic imaging of Group A streptococcus. Appl Microbiol Biotechnol 2013; 97:9737-45. [PMID: 24061415 DOI: 10.1007/s00253-013-5200-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 08/11/2013] [Accepted: 08/14/2013] [Indexed: 01/19/2023]
Abstract
Bioluminescence is a rapid and cost-efficient optical imaging technology that allows the detection of bacteria in real-time during disease development. Here, we report a novel strategy to generate a wide range of bioluminescent group A streptococcus (GAS) strains by using a toxin-antitoxin-stabilized plasmid. The bacterial luciferin-luciferase operon (lux) or the firefly luciferase gene (ffluc) was introduced into GAS via a stabilized plasmid. The FFluc reporter gave significantly stronger bioluminescent signals than the Lux reporter, and was generally more stable. Plasmid-based luciferase reporters could easily be introduced into a variety of GAS strains and the signals correlated linearly with viable cell counts. Co-expression of the streptococcal ω-ε-ζ toxin-antitoxin operon provided segregational stability in the absence of antibiotics for at least 17 passages in vitro and up to 7 days in a mouse infection model. In addition, genome-integrated reporter constructs were also generated by site-specific recombination, but were found to be technically more challenging. The quick and efficient generation of various M-type GAS strains expressing plasmid-based luciferase reporters with comparable and quantifiable bioluminescence signals allows for comparative analysis of different GAS strains in vitro and in vivo.
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Affiliation(s)
- Jacelyn M S Loh
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
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Abstract
Group A streptococcus is a strict human pathogen that can cause a wide range of diseases, such as tonsillitis, impetigo, necrotizing fasciitis, toxic shock, and acute rheumatic fever. Modeling human diseases in animals is complicated, and rapid, simple, and cost-effective in vivo models of GAS infection are clearly lacking. Recently, the use of non-mammalian models to model human disease is starting to re-attract attention. Galleria mellonella larvae, also known as wax worms, have been investigated for modeling a number of bacterial pathogens, and have been shown to be a useful model to study pathogenesis of the M3 serotype of GAS. In this study we provide further evidence of the validity of the wax worm model by testing different GAS M-types, as well as investigating the effect of bacterial growth phase and incubation temperature on GAS virulence in this model. In contrast to previous studies, we show that the M-protein, among others, is an important virulence factor that can be effectively modeled in the wax worm. We also highlight the need for a more in-depth investigation of the effects of experimental design and wax worm supply before we can properly vindicate the wax worm model for studying GAS pathogenesis.
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Affiliation(s)
- Jacelyn M S Loh
- Department of Molecular Medicine & Pathology, School of Medical Sciences, University of Auckland, Auckland, NZ
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Chang A, Khemlani A, Kang H, Proft T. Functional analysis of Streptococcus pyogenes nuclease A (SpnA), a novel group A streptococcal virulence factor. Mol Microbiol 2011; 79:1629-42. [PMID: 21231972 DOI: 10.1111/j.1365-2958.2011.07550.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Streptococcus pyogenes nuclease A (SpnA) is a recently discovered DNase that plays a role in virulence as shown in a mouse infection model. SpnA is the only cell wall-anchored DNase found in S. pyogenes thus far and shows a unique protein architecture. The C-terminal nuclease domain contains highly conserved catalytic site and Mg(2+) binding site residues. However, expression of the SpnA nuclease domain alone resulted in a soluble, but enzymatically inactive protein. We found that at least two out of three oligonucleotide/oligosaccharide-binding fold motifs found in the N-terminal domain are required for SpnA activity, probably contributing to substrate binding. Using a combination of a spnA deletion mutant and a Lactococcus lactis'gain-of-function' mutant, we have shown that SpnA promotes survival in whole human blood and in neutrophil killing assays and this is, at least in part, achieved by the destruction of neutrophil extracellular traps (NETs). We observed higher frequencies for anti-SpnA antibodies in streptococcal disease patient sera (79%, n = 19) compared with sera from healthy donors (33%, n = 9) suggesting that SpnA is expressed during infection. Detection of anti-SpnA antibodies in patient serum might be useful for the diagnostic of post-streptococcal diseases, such as acute rheumatic fever or glomerulonephritis.
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Affiliation(s)
- Ann Chang
- Department of Molecular Medicine & Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
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Linke C, Young PG, Bunker RD, Middleditch M, Caradoc-Davies TT, Proft T, Baker EN. Incorporation of the basal pilin FctB into the pilus of Streptococcus pyogenes. Acta Crystallogr A 2010. [DOI: 10.1107/s0108767310099241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Wu S, Proft T. The use of sortase-mediated ligation for the immobilisation of bacterial adhesins onto fluorescence-labelled microspheres: a novel approach to analyse bacterial adhesion to host cells. Biotechnol Lett 2010; 32:1713-8. [DOI: 10.1007/s10529-010-0349-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Accepted: 06/25/2010] [Indexed: 10/19/2022]
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Linke C, Young PG, Kang HJ, Bunker RD, Middleditch MJ, Caradoc-Davies TT, Proft T, Baker EN. Crystal structure of the minor pilin FctB reveals determinants of Group A streptococcal pilus anchoring. J Biol Chem 2010; 285:20381-9. [PMID: 20427291 DOI: 10.1074/jbc.m109.089680] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cell surface pili are polymeric protein assemblies that enable bacteria to adhere to surfaces and to specific host tissues. The pili expressed by Gram-positive bacteria constitute a unique paradigm in which sortase-mediated covalent linkages join successive pilin subunits like beads on a string. These pili are formed from two or three distinct types of pilin subunit, typically encoded in small gene clusters, often with their cognate sortases. In Group A streptococci (GAS), a major pilin forms the polymeric backbone, whereas two minor pilins are located at the tip and the base. Here, we report the 1.9-A resolution crystal structure of the GAS basal pilin FctB, revealing an immunoglobulin (Ig)-like N-terminal domain with an extended proline-rich tail. Unexpected structural homology between the FctB Ig-like domain and the N-terminal domain of the GAS shaft pilin helps explain the use of the same sortase for polymerization of the shaft and its attachment to FctB. It also enabled the identification, from mass spectral data, of the lysine residue involved in the covalent linkage of FctB to the shaft. The proline-rich tail forms a polyproline-II helix that appears to be a common feature of the basal (cell wall-anchoring) pilins. Together, our results indicate distinct structural elements in the pilin proteins that play a role in selecting for the appropriate sortases and thereby help orchestrate the ordered assembly of the pilus.
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Affiliation(s)
- Christian Linke
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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Linke C, Young PG, Kang HJ, Proft T, Baker EN. Purification, crystallization and preliminary crystallographic analysis of the minor pilin FctB from Streptococcus pyogenes. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:177-9. [PMID: 20124716 DOI: 10.1107/s1744309109051951] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Accepted: 12/02/2009] [Indexed: 08/30/2023]
Abstract
The minor pilin FctB is an integral part of the pilus assembly expressed by Streptococcus pyogenes. Since it is located at the cell wall, it can be hypothesized that it functions as a cell-wall anchor for the streptococcal pilus. In order to elucidate its structure, the genes for FctB from the S. pyogenes strains 90/306S and SF370 were cloned for overexpression in Escherichia coli. FctB from strain 90/306S was crystallized by the sitting-drop vapour-diffusion method using sodium citrate as a precipitant. The hexagonal FctB crystals belonged to space group P6(1) or P6(5), with unit-cell parameters a = b = 95.15, c = 100.25 A, and diffracted to 2.9 A resolution.
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Affiliation(s)
- Christian Linke
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
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Kang HJ, Middleditch M, Proft T, Baker EN. Isopeptide bonds in bacterial pili and their characterization by X-ray crystallography and mass spectrometry. Biopolymers 2009; 91:1126-34. [DOI: 10.1002/bip.21170] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
SUMMARY The bacterial superantigens are protein toxins that bind to major histocompatibility complex class II and T-cell receptor to stimulate large numbers of T cells. The majority are produced by the Gram-positive organisms Staphylococcus aureus and Streptococcus pyogenes and are the causative agents in toxic shock syndrome, an acute disease caused by the sudden and massive release of T-cell cytokines into the blood stream. The structure and function of the superantigens has revealed a common architecture that is also shared by another group of staphylococcal virulence factors called the superantigen-like proteins (SSL). Together, this family of structurally related molecules highlights how a common pathogenic organism has employed a simple but adaptable protein to generate an armamentarium of potent defense molecules designed to target of the innate and adaptive immune response.
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Affiliation(s)
- John D Fraser
- The Maurice Wilkins Centre for Molecular Biodiscovery & School of Medical Sciences, University of Auckland, Private Bag, Auckland, New Zealand.
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Baker E, Kang H, Coulibaly F, Clow F, Proft T. Isopeptide bonds stabilize Gram-positive bacterial pilus structure and assembly. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308087989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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50
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Linke C, Caradoc-Davies T, Proft T, Baker E. Crystal structure of the laminin-binding protein Lpb of Streptococcus pyogenes. Acta Crystallogr A 2008. [DOI: 10.1107/s010876730807918x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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