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Rivero MB, Alonso AM, Abdala ME, Luque ME, Carranza PG, Coceres VM, Rivero FD. Comparative membrane proteomic analysis of Tritrichomonas foetus isolates. Sci Rep 2024; 14:17033. [PMID: 39043862 PMCID: PMC11266394 DOI: 10.1038/s41598-024-67827-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Accepted: 07/16/2024] [Indexed: 07/25/2024] Open
Abstract
Tritrichomonas foetus is a flagellated and anaerobic parasite able to infect cattle and felines. Despite its prevalence, there is no effective standardized or legal treatment for T. foetus-infected cattle; the vaccination still has limited success in mitigating infections and reducing abortion risk; and nowadays, the diagnosis of T. foetus presents important limitations in terms of sensitivity and specificity in bovines. Here, we characterize the plasma membrane proteome of T. foetus and identify proteins that are represented in different isolates of this protozoan. Additionally, we performed a bioinformatic analysis that revealed the antigenicity potential of some of those proteins. This analysis is the first study to identify common proteins at the plasma membrane of different T. foetus isolates that could be targets for alternative diagnostic or vaccine techniques in the future.
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Affiliation(s)
- Maria B Rivero
- Laboratorio de Biología Molecular, Inmunología y Microbiología (LaBIM), Instituto Multidisciplinario de Salud, Tecnología y Desarrollo (IMSaTeD), CONICET-UNSE, Santiago del Estero, Argentina
- Facultad de Ciencias Médicas (FCM-UNSE), Santiago del Estero, Argentina
| | - Andrés M Alonso
- Laboratorio de Parásitos Anaerobios, Instituto Tecnológico Chascomús (INTECH), CONICET-UNSAM, B7130IWA, Chascomús, Argentina
- Escuela de Bio y Nanotecnologías (UNSAM), Buenos Aires, Argentina
| | - Maria E Abdala
- Laboratorio de Biología Molecular, Inmunología y Microbiología (LaBIM), Instituto Multidisciplinario de Salud, Tecnología y Desarrollo (IMSaTeD), CONICET-UNSE, Santiago del Estero, Argentina
- Facultad de Ciencias Médicas (FCM-UNSE), Santiago del Estero, Argentina
- Facultad de Agronomía y Agroindustrias (FAyA-UNSE), Santiago del Estero, Argentina
| | - Melchor E Luque
- Laboratorio de Biología Molecular, Inmunología y Microbiología (LaBIM), Instituto Multidisciplinario de Salud, Tecnología y Desarrollo (IMSaTeD), CONICET-UNSE, Santiago del Estero, Argentina
- Facultad de Ciencias Médicas (FCM-UNSE), Santiago del Estero, Argentina
- Facultad de Agronomía y Agroindustrias (FAyA-UNSE), Santiago del Estero, Argentina
| | - Pedro G Carranza
- Laboratorio de Biología Molecular, Inmunología y Microbiología (LaBIM), Instituto Multidisciplinario de Salud, Tecnología y Desarrollo (IMSaTeD), CONICET-UNSE, Santiago del Estero, Argentina
- Facultad de Ciencias Médicas (FCM-UNSE), Santiago del Estero, Argentina
- Facultad de Agronomía y Agroindustrias (FAyA-UNSE), Santiago del Estero, Argentina
| | - Veronica M Coceres
- Laboratorio de Parásitos Anaerobios, Instituto Tecnológico Chascomús (INTECH), CONICET-UNSAM, B7130IWA, Chascomús, Argentina.
- Escuela de Bio y Nanotecnologías (UNSAM), Buenos Aires, Argentina.
| | - Fernando D Rivero
- Laboratorio de Biología Molecular, Inmunología y Microbiología (LaBIM), Instituto Multidisciplinario de Salud, Tecnología y Desarrollo (IMSaTeD), CONICET-UNSE, Santiago del Estero, Argentina.
- Facultad de Ciencias Médicas (FCM-UNSE), Santiago del Estero, Argentina.
- Facultad de Agronomía y Agroindustrias (FAyA-UNSE), Santiago del Estero, Argentina.
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2
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Manning J, Manna S, Dunne EM, Bongcaron V, Pell CL, Patterson NL, Kuil SD, Dhar P, Goldblatt D, Kim Mulholland E, Licciardi PV, Robins-Browne RM, Malley R, Wijburg O, Satzke C. Immunization with a whole cell vaccine reduces pneumococcal nasopharyngeal density and shedding, and middle ear infection in mice. Vaccine 2024; 42:1714-1722. [PMID: 38350767 DOI: 10.1016/j.vaccine.2024.01.104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 11/16/2023] [Accepted: 01/31/2024] [Indexed: 02/15/2024]
Abstract
Pneumococcal Conjugate Vaccines (PCVs) have substantially reduced the burden of disease caused by Streptococcus pneumoniae (the pneumococcus). However, protection is limited to vaccine serotypes, and when administered to children who are colonized with pneumococci at the time of vaccination, immune responses to the vaccine are blunted. Here, we investigate the potential of a killed whole cell pneumococcal vaccine (WCV) to reduce existing pneumococcal carriage and mucosal disease when given therapeutically to infant mice colonized with pneumococci. We show that a single dose of WCV reduced pneumococcal carriage density in an antibody-dependent manner. Therapeutic vaccination induced robust immune responses to pneumococcal surface antigens CbpA, PspA (family 1) and PiaA. In a co-infection model of otitis media, a single dose of WCV reduced pneumococcal middle ear infection. Lastly, in a two-dose model, therapeutic administration of WCV reduced nasal shedding of pneumococci. Taken together, our data demonstrate that WCV administered in colonized mice reduced pneumococcal density in the nasopharynx and the middle ear, and decreased shedding. WCVs would be beneficial in low and middle-income settings where pneumococcal carriage in children is high.
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Affiliation(s)
- Jayne Manning
- Translational Microbiology, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia; Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Sam Manna
- Translational Microbiology, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia; Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; Department of Paediatrics, Royal Children's Hospital, The University of Melbourne, Melbourne, Victoria, Australia
| | - Eileen M Dunne
- Translational Microbiology, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia; Department of Paediatrics, Royal Children's Hospital, The University of Melbourne, Melbourne, Victoria, Australia
| | - Viktoria Bongcaron
- Translational Microbiology, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia; Department of Paediatrics, Royal Children's Hospital, The University of Melbourne, Melbourne, Victoria, Australia
| | - Casey L Pell
- Translational Microbiology, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Natalie L Patterson
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Sacha D Kuil
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Poshmaal Dhar
- Faculty of Health, School of Medicine, Deakin University, Geelong, Victoria, Australia
| | - David Goldblatt
- Institute of Child Health, University College London, London, United Kingdom
| | - E Kim Mulholland
- New Vaccines, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia; Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Paul V Licciardi
- Department of Paediatrics, Royal Children's Hospital, The University of Melbourne, Melbourne, Victoria, Australia; New Vaccines, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Roy M Robins-Browne
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; Infectious Diseases, Murdoch Children's Research Institute, Parkville, VIC, Australia
| | - Richard Malley
- Division of Infectious Diseases, Boston Children's Hospital, Boston, United States of America
| | - Odilia Wijburg
- Translational Microbiology, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia; Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Catherine Satzke
- Translational Microbiology, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia; Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; Department of Paediatrics, Royal Children's Hospital, The University of Melbourne, Melbourne, Victoria, Australia.
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3
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Li S, Liang H, Zhao SH, Yang XY, Guo Z. Recent progress in pneumococcal protein vaccines. Front Immunol 2023; 14:1278346. [PMID: 37818378 PMCID: PMC10560988 DOI: 10.3389/fimmu.2023.1278346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 09/07/2023] [Indexed: 10/12/2023] Open
Abstract
Pneumococcal infections continue to pose a significant global health concern, necessitating the development of effective vaccines. Despite the progress shown by pneumococcal polysaccharide and conjugate vaccines, their limited coverage and the emergence of non-vaccine serotypes have highlighted the need for alternative approaches. Protein-based pneumococcal vaccines, targeting conserved surface proteins of Streptococcus pneumoniae, have emerged as a promising strategy. In this review, we provide an overview of the advancements made in the development of pneumococcal protein vaccines. We discuss the key protein vaccine candidates, highlight their vaccination results in animal studies, and explore the challenges and future directions in protein-based pneumococcal vaccine.
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Affiliation(s)
- Sha Li
- Zhuhai Key Laboratory of Basic and Applied Research in Chinese Medicine, School of Bioengineering, Zunyi Medical University, Zhuhai, Guangdong, China
| | - Hangeri Liang
- Zhuhai Key Laboratory of Basic and Applied Research in Chinese Medicine, School of Bioengineering, Zunyi Medical University, Zhuhai, Guangdong, China
| | - Shui-Hao Zhao
- Center for Biological Science and Technology, Advanced Institute of Natural Sciences, Beijing Normal University, Zhuhai, Guangdong, China
| | - Xiao-Yan Yang
- Zhuhai Key Laboratory of Basic and Applied Research in Chinese Medicine, School of Bioengineering, Zunyi Medical University, Zhuhai, Guangdong, China
| | - Zhong Guo
- Center for Biological Science and Technology, Advanced Institute of Natural Sciences, Beijing Normal University, Zhuhai, Guangdong, China
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4
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Akhtar AA, Turner DP. The role of bacterial ATP-binding cassette (ABC) transporters in pathogenesis and virulence: Therapeutic and vaccine potential. Microb Pathog 2022; 171:105734. [PMID: 36007845 DOI: 10.1016/j.micpath.2022.105734] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 08/17/2022] [Accepted: 08/18/2022] [Indexed: 11/24/2022]
Abstract
The ATP-binding cassette (ABC) transporter superfamily is found in all domains of life, facilitating critical biological processes through the translocation of a wide variety of substrates from, ions to proteins, across cellular membranes in an ATP-coupled process. The role of ABC transporters in eukaryotes has been well established: the facilitation of genetic diseases and multi-drug resistance (MDR) in cancer patients. In contrast, the role of ABC transporters in prokaryotes has been ambiguous due to their diverse functions and the sheer number of organisms in which they reside. This review examines the role of bacterial ABC transporters in pathogenesis and virulence, and their potential for therapeutic and vaccine application. We demonstrate how ABC transporters play a vital role in the virulence and pathogenesis of several pathogenic bacteria through the import of essential molecules, such as metal ions, amino acids, peptides, vitamins and osmoprotectants, as well as, the export of virulent determinants involved in glycoconjugate biosynthesis and Type I secretion. Furthermore, ABC exporters facilitate the persistence of pathogenic bacteria through the export of toxic xenobiotic substances, thus, contributing to the development of antimicrobial resistance. We also show that ABC transporters display considerable potential for therapeutic application through immunisation and resistance reversal. In conclusion, bacterial ABC transporters play an immense role in virulence and pathogenesis and display desirable traits for clinical use, therefore, potentially aiding in the battle against MDR.
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Affiliation(s)
- Armaan A Akhtar
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom.
| | - David Pj Turner
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
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5
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Hisyam Bin Ismail CMK, Raihan Mohammad Shabani N, Chuah C, Hassan Z, Bakar Abdul Majeed A, Herng Leow C, Kaur Banga Singh K, Yee Leow C. Shigella iron-binding proteins: An insight into molecular physiology, pathogenesis, and potential target vaccine development. Vaccine 2022; 40:3991-3998. [PMID: 35660036 DOI: 10.1016/j.vaccine.2022.05.061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 11/21/2021] [Accepted: 05/19/2022] [Indexed: 12/01/2022]
Abstract
Shigella is a well-known etiological agent responsible for intestinal infection among children, the elderly, and immunocompromised people ranging from mild to severe cases. Shigellosis remains endemic in Malaysia and yet there is no commercial vaccine available to eradicate the disease. Iron is an essential element for the survival of Shigella within the host. Hence, it is required for regulating metabolic mechanisms and virulence determinants. Alteration of iron status in the extracellular environment directly triggers the signal in enteropathogenic bacterial, providing information that they are in a hostile environment. To survive in an iron-limited environment, molecular regulation of iron-binding proteins plays a vital role in facilitating the transportation and utilization of sufficient iron sources. Given the importance of iron molecules for bacterial survival and pathogenicity, this review summarizes the physiological role of iron-binding proteins in bacterial survival and their potential use in vaccine and therapeutic developments.
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Affiliation(s)
| | - Nor Raihan Mohammad Shabani
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia; Faculty of Health Sciences, Universiti Teknologi MARA, Kampus Bertam, 13200 Kepala Batas, Penang, Malaysia
| | - Candy Chuah
- Department of Medical and Parasitology, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia; Faculty of Health Sciences, Universiti Teknologi MARA, Kampus Bertam, 13200 Kepala Batas, Penang, Malaysia
| | - Zurina Hassan
- Centre for Drug Research, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia
| | - Abu Bakar Abdul Majeed
- Faculty of Pharmacy, Universiti Teknologi MARA, Kampus Puncak Alam, 42300 Kuala Selangor, Selangor, Malaysia
| | - Chiuan Herng Leow
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia
| | - Kirnpal Kaur Banga Singh
- Department of Medical and Parasitology, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Chiuan Yee Leow
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia.
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6
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Identification and Tetramer Structure of Hemin-Binding Protein SPD_0310 Linked to Iron Homeostasis and Virulence of Streptococcus pneumoniae. mSystems 2022; 7:e0022122. [PMID: 35414267 PMCID: PMC9238395 DOI: 10.1128/msystems.00221-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Iron and iron-containing compounds are essential for bacterial virulence and host infection. Hemin is an important supplement compound for bacterial survival in an iron-deficient environment. Despite strong interest in hemin metabolism, the detailed mechanism of hemin transportation in Gram-positive bacteria is yet to be reported. The results of our study revealed that the homologous proteins of SPD_0310 were significantly conservative in Gram-positive bacteria (P < 0.001), and these proteins were identified as belonging to an uncharacterized protein family (UPF0371). The results of thermodynamic and kinetic studies have shown that SPD_0310 has a high hemin-binding affinity. Interestingly, we found that the crystal structure of SPD_0310 presented a homotetramer conformation, which is required for hemin binding. SPD_0310 can interact with many hemin-binding proteins (SPD_0090, SPD_1609, and GAPDH) located on the cell surface, which contributes to hemin transfer to the cytoplasm. It also has a high affinity with other iron transporters in the cytoplasm (SPD_0226 and SPD_0227), which facilitates iron redistribution in cells. More importantly, the knockout of the spd_0310 gene (Δspd_0310) resulted in a decrease in the iron content and protein expression levels of many bacterial adhesion factors. Moreover, the animal model showed that the Δspd_0310 strain has a lower virulence than the wild type. Based on the crystallographic and biochemical studies, we inferred that SPD_0310 is a hemin intermediate transporter which contributes to iron homeostasis and further affects the virulence of Streptococcus pneumoniae in the host. Our study provides not only an important theoretical basis for the in-depth elucidation of the hemin transport mechanism in bacteria but also an important candidate target for the development of novel antimicrobial agents based on metal transport systems. IMPORTANCE Iron is an essential element for bacterial virulence and infection of the host. The detailed hemin metabolism in Gram-positive bacteria has rarely been studied. SPD_0310 belongs to the UPF0371 family of proteins, and results of homology analysis and evolutionary tree analysis suggested that it was widely distributed and highly conserved in Gram-positive bacteria. However, the function of the UPF0371 family remains unknown. We successfully determined the crystal structure of apo-SPD_0310, which is a homotetramer. We found that cytoplasmic protein SPD_0310 with a special tetramer structure has a strong hemin-binding ability and interacts with many iron transporters, which facilitates hemin transfer from the extracellular space to the cytoplasm. The results of detailed functional analyses indicated that SPD_0310 may function as a hemin transporter similar to hemoglobin in animals and contributes to bacterial iron homeostasis and virulence. This study provides a novel target for the development of antimicrobial drugs against pathogenic Gram-positive bacteria.
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Chan WY, Entwisle C, Ercoli G, Ramos-Sevillano E, McIlgorm A, Cecchini P, Bailey C, Lam O, Whiting G, Green N, Goldblatt D, Wheeler JX, Brown JS. Corrected and Republished from: "A Novel, Multiple-Antigen Pneumococcal Vaccine Protects against Lethal Streptococcus pneumoniae Challenge". Infect Immun 2022; 90:e0084618a. [PMID: 35076289 PMCID: PMC9199499 DOI: 10.1128/iai.00846-18a] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 11/29/2018] [Indexed: 11/20/2022] Open
Abstract
Current vaccination against Streptococcus pneumoniae uses vaccines based on capsular polysaccharides from selected serotypes and has led to nonvaccine serotype replacement disease. We have investigated an alternative serotype-independent approach, using multiple-antigen vaccines (MAV) prepared from S. pneumoniae TIGR4 lysates enriched for surface proteins by a chromatography step after culture under conditions that induce expression of heat shock proteins (Hsp; thought to be immune adjuvants). Proteomics and immunoblot analyses demonstrated that, compared to standard bacterial lysates, MAV was enriched with Hsps and contained several recognized protective protein antigens, including pneumococcal surface protein A (PspA) and pneumolysin (Ply). Vaccination of rodents with MAV induced robust antibody responses to multiple serotypes, including nonpneumococcal conjugate vaccine serotypes. Homologous and heterologous strains of S. pneumoniae were opsonized after incubation in sera from vaccinated rodents. In mouse models, active vaccination with MAV significantly protected against pneumonia, while passive transfer of rabbit serum from MAV-vaccinated rabbits significantly protected against sepsis caused by both homologous and heterologous S. pneumoniae strains. Direct comparison of MAV preparations made with or without the heat shock step showed no clear differences in protein antigen content and antigenicity, suggesting that the chromatography step rather than Hsp induction improved MAV antigenicity. Overall, these data suggest that the MAV approach may provide serotype-independent protection against S. pneumoniae.
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Affiliation(s)
- Win-Yan Chan
- Centre for Inflammation and Tissue Repair, UCL Respiratory, Division of Medicine, University College Medical School Rayne Institute, London, United Kingdom
| | | | - Giuseppe Ercoli
- Centre for Inflammation and Tissue Repair, UCL Respiratory, Division of Medicine, University College Medical School Rayne Institute, London, United Kingdom
| | - Elise Ramos-Sevillano
- Centre for Inflammation and Tissue Repair, UCL Respiratory, Division of Medicine, University College Medical School Rayne Institute, London, United Kingdom
| | - Ann McIlgorm
- ImmunoBiology Ltd., Babraham, Cambridge, United Kingdom
| | | | | | - Oliver Lam
- National Institute for Biological Standards and Control, South Mimms, Potters Bar, Hertfordshire, United Kingdom
| | - Gail Whiting
- National Institute for Biological Standards and Control, South Mimms, Potters Bar, Hertfordshire, United Kingdom
| | - Nicola Green
- UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - David Goldblatt
- UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Jun X. Wheeler
- National Institute for Biological Standards and Control, South Mimms, Potters Bar, Hertfordshire, United Kingdom
| | - Jeremy S. Brown
- Centre for Inflammation and Tissue Repair, UCL Respiratory, Division of Medicine, University College Medical School Rayne Institute, London, United Kingdom
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8
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Venkataranganayaka Abhilasha K, Kedihithlu Marathe G. Bacterial lipoproteins in sepsis. Immunobiology 2021; 226:152128. [PMID: 34488139 DOI: 10.1016/j.imbio.2021.152128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 07/09/2021] [Accepted: 08/10/2021] [Indexed: 01/05/2023]
Abstract
Bacterial lipoproteins are membrane proteins derived from both gram-negative and gram-positive bacteria. They seem to have diverse functions not only on bacterial growth, but also play an important role in host's virulence. Bacterial lipoproteins exert their action on host immune cells via TLR2/1 or TLR2/6. Therefore, bacterial lipoproteins also need to be considered while addressing bacterial pathogenicity besides classical bacterial endotoxin like LPS and other microbial associated molecular patterns such as LTA, and peptidoglycans. In this mini-review, we provide an overview of general bacterial lipoprotein biosynthesis and the need to understand the lipoprotein-mediated pathogenicity in diseases like sepsis.
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Affiliation(s)
- Kandahalli Venkataranganayaka Abhilasha
- Department of Studies in Biochemistry, University of Mysore, Manasagangothri, Mysuru 570006, Karnataka, India; Cancer and Developmental Biology Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | - Gopal Kedihithlu Marathe
- Department of Studies in Biochemistry, University of Mysore, Manasagangothri, Mysuru 570006, Karnataka, India; Department of Studies in Molecular Biology, University of Mysore, Manasagangothri, Mysuru 570006, Karnataka, India.
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9
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Converso TR, Assoni L, André GO, Darrieux M, Leite LCC. The long search for a serotype independent pneumococcal vaccine. Expert Rev Vaccines 2020; 19:57-70. [PMID: 31903805 DOI: 10.1080/14760584.2020.1711055] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Introduction: Serotype replacement - a consequence of polysaccharide vaccine use - will continue to drive the inclusion of new serotypes on conjugate vaccines, increasing production complexity and costs, and making an already expensive vaccine less accessible to developing countries, where prevalence is higher and resources available for health systems, scarcer. Serotype-independent formulations are a promising option, but so far they have not been successful in reducing colonization/transmission.Areas covered: Protein-based and whole-cell vaccine candidates studied in the past 30 years. Challenges for serotype-independent vaccine development and alternative approaches.Expert opinion: Clinical trials performed so far demonstrated the importance to establish more reliable animal models and better correlates of protection. Defining appropriate endpoints for clinical trials of serotype-independent vaccine candidates has been a challenge. Inhibition of colonization has been evaluated, but concern on the extent of bacterial elimination is still a matter of debate. Challenges on establishing representative sites for clinical trials, sample sizes and appropriate age groups are discussed. On a whole, although many challenges will have to be overcome, establishing protein-based antigens as serotype-independent vaccines is still the best alternative against the huge burden of pneumococcal diseases in the world.
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Affiliation(s)
- T R Converso
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - L Assoni
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - G O André
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - M Darrieux
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - L C C Leite
- Laboratório de Desenvolvimento de Vacinas, Instituto Butantan, São Paulo, SP, Brazil
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10
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Briles DE, Paton JC, Mukerji R, Swiatlo E, Crain MJ. Pneumococcal Vaccines. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0028-2018. [PMID: 31858954 PMCID: PMC10921951 DOI: 10.1128/microbiolspec.gpp3-0028-2018] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Indexed: 01/14/2023] Open
Abstract
Streptococcus pneumoniae is a Gram-Positive pathogen that is a major causative agent of pneumonia, otitis media, sepsis and meningitis across the world. The World Health Organization estimates that globally over 500,000 children are killed each year by this pathogen. Vaccines offer the best protection against S. pneumoniae infections. The current polysaccharide conjugate vaccines have been very effective in reducing rates of invasive pneumococcal disease caused by vaccine type strains. However, the effectiveness of these vaccines have been somewhat diminished by the increasing numbers of cases of invasive disease caused by non-vaccine type strains, a phenomenon known as serotype replacement. Since, there are currently at least 98 known serotypes of S. pneumoniae, it may become cumbersome and expensive to add many additional serotypes to the current 13-valent vaccine, to circumvent the effect of serotype replacement. Hence, alternative serotype independent strategies, such as vaccination with highly cross-reactive pneumococcal protein antigens, should continue to be investigated to address this problem. This chapter provides a comprehensive discussion of pneumococcal vaccines past and present, protein antigens that are currently under investigation as vaccine candidates, and other alternatives, such as the pneumococcal whole cell vaccine, that may be successful in reducing current rates of disease caused by S. pneumoniae.
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Affiliation(s)
- D E Briles
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama
| | - J C Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, 5005, Australia
| | - R Mukerji
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama
| | - E Swiatlo
- Section of Infectious Diseases, Southeast Louisiana Veterans Health Care System, New Orleans, LA
| | - M J Crain
- Department of Pediatrics and Microbiology, University of Alabama at Birmingham
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11
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Yang XY, Li N, Xu JY, Sun X, He QY. Lipoprotein SPD_1609 of Streptococcus pneumoniae Promotes Adherence and Invasion to Epithelial Cells Contributing to Bacterial Virulence. Front Microbiol 2019; 10:1769. [PMID: 31417540 PMCID: PMC6682666 DOI: 10.3389/fmicb.2019.01769] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 07/17/2019] [Indexed: 01/06/2023] Open
Abstract
In most bacteria, iron plays a vital role in pathogenesis processes. To support survival and infection, Streptococcus pneumoniae has evolved three ABC transporters, PiaABC, PiuABC, and PitABC. Moreover, indirect evidence supports that operon 804 may be a novel ABC transporter in S. pneumoniae. We have recently described the identification of lipoprotein SPD_1609 in operon 804; however, whether the SPD_1609 protein affects the virulence of S. pneumoniae has not yet been studied. In the present work, alignment analysis showed that lipoprotein SPD_1609 is conserved in a variety of gram-positive bacteria, and deletion of the spd_1609 gene led to a reduction in adherence and invasion of S. pneumoniae to host cells. RT-qPCR assays indicated that deletion of the spd_1609 gene resulted in decreased expression of genes involved in colonization. Furthermore, decreased virulence in a mouse bacteremia infection model caused by the loss of the lipoprotein encoded by spd_1609 was also demonstrated. Overall, these data provide insights into the functional role of lipoprotein SPD_1609 in pneumococcal pathogenesis, suggesting its possibility to be developed as a novel S. pneumoniae vaccine candidate.
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Affiliation(s)
- Xiao-Yan Yang
- Zhuhai Key Laboratory of Basic and Applied Research in Chinese Medicine, Department of Bioengineering, Zhuhai Campus of Zunyi Medical University, Zhuhai, China.,Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
| | - Nan Li
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
| | - Jing-Yu Xu
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
| | - Xuesong Sun
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
| | - Qing-Yu He
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
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12
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A Novel, Multiple-Antigen Pneumococcal Vaccine Protects against Lethal Streptococcus pneumoniae Challenge. Infect Immun 2019; 87:IAI.00846-18. [PMID: 30530620 PMCID: PMC6386546 DOI: 10.1128/iai.00846-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 11/29/2018] [Indexed: 01/07/2023] Open
Abstract
Current vaccination against Streptococcus pneumoniae uses vaccines based on capsular polysaccharides from selected serotypes and has led to nonvaccine serotype replacement disease. We have investigated an alternative serotype-independent approach, using multiple-antigen vaccines (MAV) prepared from S. pneumoniae TIGR4 lysates enriched for surface proteins by a chromatography step after culture under conditions that induce expression of heat shock proteins (Hsp; thought to be immune adjuvants). Current vaccination against Streptococcus pneumoniae uses vaccines based on capsular polysaccharides from selected serotypes and has led to nonvaccine serotype replacement disease. We have investigated an alternative serotype-independent approach, using multiple-antigen vaccines (MAV) prepared from S. pneumoniae TIGR4 lysates enriched for surface proteins by a chromatography step after culture under conditions that induce expression of heat shock proteins (Hsp; thought to be immune adjuvants). Proteomics and immunoblot analyses demonstrated that, compared to standard bacterial lysates, MAV was enriched with Hsps and contained several recognized protective protein antigens, including pneumococcal surface protein A (PspA) and pneumolysin (Ply). Vaccination of rodents with MAV induced robust antibody responses to multiple serotypes, including nonpneumococcal conjugate vaccine serotypes. Homologous and heterologous strains of S. pneumoniae were opsonized after incubation in sera from vaccinated rodents. In mouse models, active vaccination with MAV significantly protected against pneumonia, while passive transfer of rabbit serum from MAV-vaccinated rabbits significantly protected against sepsis caused by both homologous and heterologous S. pneumoniae strains. Direct comparison of MAV preparations made with or without the heat shock step showed no clear differences in protein antigen content and antigenicity, suggesting that the chromatography step rather than Hsp induction improved MAV antigenicity. Overall, these data suggest that the MAV approach may provide serotype-independent protection against S. pneumoniae.
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13
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Kim YS, Yoon NK, Karisa N, Seo SH, Lee JS, Yoo SS, Yoon IJ, Kim YC, Lee H, Ahn J. Identification of novel immunogenic proteins against Streptococcus parauberis in a zebrafish model by reverse vaccinology. Microb Pathog 2019; 127:56-59. [DOI: 10.1016/j.micpath.2018.11.053] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 11/20/2018] [Accepted: 11/29/2018] [Indexed: 10/27/2022]
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14
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Campo JJ, Le TQ, Pablo JV, Hung C, Teng AA, Tettelin H, Tate A, Hanage WP, Alderson MR, Liang X, Malley R, Lipsitch M, Croucher NJ. Panproteome-wide analysis of antibody responses to whole cell pneumococcal vaccination. eLife 2018; 7:e37015. [PMID: 30592459 PMCID: PMC6344088 DOI: 10.7554/elife.37015] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 12/25/2018] [Indexed: 11/13/2022] Open
Abstract
Pneumococcal whole cell vaccines (WCVs) could cost-effectively protect against a greater strain diversity than current capsule-based vaccines. Immunoglobulin G (IgG) responses to a WCV were characterised by applying longitudinally-sampled sera, available from 35 adult placebo-controlled phase I trial participants, to a panproteome microarray. Despite individuals maintaining distinctive antibody 'fingerprints', responses were consistent across vaccinated cohorts. Seventy-two functionally distinct proteins were associated with WCV-induced increases in IgG binding. These shared characteristics with naturally immunogenic proteins, being enriched for transporters and cell wall metabolism enzymes, likely unusually exposed on the unencapsulated WCV's surface. Vaccine-induced responses were specific to variants of the diverse PclA, PspC and ZmpB proteins, whereas PspA- and ZmpA-induced antibodies recognised a broader set of alleles. Temporal variation in IgG levels suggested a mixture of anamnestic and novel responses. These reproducible increases in IgG binding to a limited, but functionally diverse, set of conserved proteins indicate WCV could provide species-wide immunity. Clinical trial registration: The trial was registered with ClinicalTrials.gov with Identifier NCT01537185; the results are available from https://clinicaltrials.gov/ct2/show/results/NCT01537185.
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Affiliation(s)
| | | | | | | | - Andy A Teng
- Antigen Discovery IncCaliforniaUnited States
| | - Hervé Tettelin
- Institute for Genome Sciences, School of MedicineUniversity of MarylandBaltimoreUnited States
| | | | - William P Hanage
- Center for Communicable Disease Dynamics, Department of EpidemiologyHarvard TH Chan School of Public HealthBostonUnited States
| | | | | | - Richard Malley
- Division of Infectious Diseases, Department of MedicineBoston Children’s Hospital and Harvard Medical SchoolBostonUnited States
| | - Marc Lipsitch
- Center for Communicable Disease Dynamics, Department of EpidemiologyHarvard TH Chan School of Public HealthBostonUnited States
- Department of Immunology and Infectious DiseasesHarvard TH Chan School of Public HealthBostonUnited States
| | - Nicholas J Croucher
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease EpidemiologyImperial College LondonLondonUnited Kingdom
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15
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Tanaka KJ, Song S, Mason K, Pinkett HW. Selective substrate uptake: The role of ATP-binding cassette (ABC) importers in pathogenesis. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2018; 1860:868-877. [PMID: 28847505 PMCID: PMC5807212 DOI: 10.1016/j.bbamem.2017.08.011] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/11/2017] [Accepted: 08/16/2017] [Indexed: 01/14/2023]
Abstract
The uptake of nutrients, including metals, amino acids and peptides are required for many biological processes. Pathogenic bacteria scavenge these essential nutrients from microenvironments to survive within the host. Pathogens must utilize a myriad of mechanisms to acquire these essential nutrients from the host while mediating the effects of toxicity. Bacteria utilize several transport proteins, including ATP-binding cassette (ABC) transporters to import and expel substrates. ABC transporters, conserved across all organisms, are powered by the energy from ATP to move substrates across cellular membranes. In this review, we will focus on nutrient uptake, the role of ABC importers at the host-pathogen interface, and explore emerging therapies to combat pathogenesis. This article is part of a Special Issue entitled: Beyond the Structure-Function Horizon of Membrane Proteins edited by Ute Hellmich, Rupak Doshi and Benjamin McIlwain.
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Affiliation(s)
- Kari J Tanaka
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Saemee Song
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Kevin Mason
- The Research Institute at Nationwide Children's Hospital and The Ohio State University, College of Medicine, Department of Pediatrics, Center for Microbial Pathogenesis, Columbus, OH, USA
| | - Heather W Pinkett
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.
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16
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Cao K, Zhang J, Miao XY, Wei QX, Zhao XL, He QY, Sun X. Evolution and molecular mechanism of PitAs in iron transport of Streptococcus species. J Inorg Biochem 2018; 182:113-123. [PMID: 29455001 DOI: 10.1016/j.jinorgbio.2018.02.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 02/05/2018] [Accepted: 02/07/2018] [Indexed: 12/24/2022]
Abstract
Iron is an essential element for almost all bacteria. The iron ATP-binding cassette (ABC) transporters located on the cell membrane affects bacterial virulence and infection. Although a variety of Fe3+-transporters have been found in bacteria, their evolutionary processes are rarely studied. Pneumococcal iron ABC transporter (PitA), a highly conserved Fe3+-transporter in most pathogenic bacteria, influences the capsule formation and virulence of bacteria. However, multiple sequence alignment revealed that PitA is expressed in four different variants in bacteria, and the structural complexity of these variants increases progressively. To more efficiently import Fe3+ ions into bacterial cells, bacteria have evolved a fused PitA from two separately expressed PitA-1 (SPD_0227) and PitA-2 (SPD_0226) proteins. Further biochemical characterization indicated that both PitA-1 and PitA-2 have weaker Fe3+-binding ability than their protein complex. More importantly, Glutathione S-Transferase (GST) pull-down and isothermal titration calorimetry (ITC) detection showed that PitA-1 and PitA-2 interact with each other via Tyr111-Leu37, Asn112-Gln38, Asn103-Leu33, and Asn103-Thr34. Further molecular dynamics (MD) simulations demonstrated that this interaction in full-length PitA is stronger than that in the two individual proteins. Deletion of PitA family genes could lead to decrease in the ability of iron acquisition and of adhesion and invasion of S. pneumoniae. Our study revealed the evolving state and molecular mechanism of Fe3+-transporter PitAs in bacteria and provided important information for understanding the iron transportation mechanism in bacteria and designing new antibacterial drugs.
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Affiliation(s)
- Kun Cao
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China
| | - Jing Zhang
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China
| | - Xin-Yu Miao
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China
| | - Qiu-Xia Wei
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China
| | - Xin-Lu Zhao
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China
| | - Qing-Yu He
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China.
| | - Xuesong Sun
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China.
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17
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Lourenço J, Watkins ER, Obolski U, Peacock SJ, Morris C, Maiden MCJ, Gupta S. Lineage structure of Streptococcus pneumoniae may be driven by immune selection on the groEL heat-shock protein. Sci Rep 2017; 7:9023. [PMID: 28831154 PMCID: PMC5567354 DOI: 10.1038/s41598-017-08990-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 07/20/2017] [Indexed: 12/29/2022] Open
Abstract
Populations of Streptococcus pneumoniae (SP) are typically structured into groups of closely related organisms or lineages, but it is not clear whether they are maintained by selection or neutral processes. Here, we attempt to address this question by applying a machine learning technique to SP whole genomes. Our results indicate that lineages evolved through immune selection on the groEL chaperone protein. The groEL protein is part of the groESL operon and enables a large range of proteins to fold correctly within the physical environment of the nasopharynx, thereby explaining why lineage structure is so stable within SP despite high levels of genetic transfer. SP is also antigenically diverse, exhibiting a variety of distinct capsular serotypes. Associations exist between lineage and capsular serotype but these can be easily perturbed, such as by vaccination. Overall, our analyses indicate that the evolution of SP can be conceptualized as the rearrangement of modular functional units occurring on several different timescales under different pressures: some patterns have locked in early (such as the epistatic interactions between groESL and a constellation of other genes) and preserve the differentiation of lineages, while others (such as the associations between capsular serotype and lineage) remain in continuous flux.
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Affiliation(s)
- José Lourenço
- Department of Zoology, University of Oxford, Oxford, United Kingdom.
| | | | - Uri Obolski
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Samuel J Peacock
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | | | | | - Sunetra Gupta
- Department of Zoology, University of Oxford, Oxford, United Kingdom
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18
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Diverse evolutionary patterns of pneumococcal antigens identified by pangenome-wide immunological screening. Proc Natl Acad Sci U S A 2017; 114:E357-E366. [PMID: 28053228 DOI: 10.1073/pnas.1613937114] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Characterizing the immune response to pneumococcal proteins is critical in understanding this bacterium's epidemiology and vaccinology. Probing a custom-designed proteome microarray with sera from 35 healthy US adults revealed a continuous distribution of IgG affinities for 2,190 potential antigens from the species-wide pangenome. Reproducibly elevated IgG binding was elicited by 208 "antibody binding targets" (ABTs), which included 109 variants of the diverse pneumococcal surface proteins A and C (PspA and PspC) and zinc metalloprotease A and B (ZmpA and ZmpB) proteins. Functional analysis found ABTs were enriched in motifs for secretion and cell surface association, with extensive representation of cell wall synthesis machinery, adhesins, transporter solute-binding proteins, and degradative enzymes. ABTs were associated with stronger evidence for evolving under positive selection, although this varied between functional categories, as did rates of diversification through recombination. Particularly rapid variation was observed at some immunogenic accessory loci, including a phage protein and a phase-variable glycosyltransferase ubiquitous among the diverse set of genomic islands encoding the serine-rich PsrP glycoprotein. Nevertheless, many antigens were conserved in the core genome, and strains' antigenic profiles were generally stable. No strong evidence was found for any epistasis between antigens driving population dynamics, or redundancy between functionally similar accessory ABTs, or age stratification of antigen profiles. These results highlight the paradox of why substantial variation is observed in only a subset of epitopes. This result may indicate only some interactions between immunoglobulins and ABTs clear pneumococcal colonization or that acquired immunity to pneumococci is an accumulation of individually weak responses to ABTs evolving under different levels of functional constraint.
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19
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Manzoor I, Shafeeq S, Kuipers OP. Ni2+-Dependent and PsaR-Mediated Regulation of the Virulence Genes pcpA, psaBCA, and prtA in Streptococcus pneumoniae. PLoS One 2015; 10:e0142839. [PMID: 26562538 PMCID: PMC4643063 DOI: 10.1371/journal.pone.0142839] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 10/27/2015] [Indexed: 11/19/2022] Open
Abstract
Previous studies have shown that the transcriptional regulator PsaR regulates the expression of the PsaR regulon consisting of genes encoding choline binding protein (PcpA), the extracellular serine protease (PrtA), and the Mn2+-uptake system (PsaBCA), in the presence of manganese (Mn2+), zinc (Zn2+), and cobalt (Co2+). In this study, we explore the Ni2+-dependent regulation of the PsaR regulon. We have demonstrated by qRT-PCR analysis, metal accumulation assays, β-galactosidase assays, and electrophoretic mobility shift assays that an elevated concentration of Ni2+ leads to strong induction of the PsaR regulon. Our ICP-MS data show that the Ni2+-dependent expression of the PsaR regulon is directly linked to high, cell-associated, concentration of Ni2+, which reduces the cell-associated concentration of Mn2+. In vitro studies with the purified PsaR protein showed that Ni2+ diminishes the Mn2+-dependent interaction of PsaR to the promoter regions of its target genes, confirming an opposite effect of Mn2+ and Ni2+ in the regulation of the PsaR regulon. Additionally, the Ni2+-dependent role of PsaR in the regulation of the PsaR regulon was studied by transcriptome analysis.
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Affiliation(s)
- Irfan Manzoor
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
- Department of Bioinformatics and Biotechnology, Government College University, Faisalabad, Pakistan
| | - Sulman Shafeeq
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Nobels väg 16, 17177, Stockholm, Sweden
| | - Oscar P. Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
- * E-mail:
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20
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Honsa ES, Johnson MDL, Rosch JW. The roles of transition metals in the physiology and pathogenesis of Streptococcus pneumoniae. Front Cell Infect Microbiol 2013; 3:92. [PMID: 24364001 PMCID: PMC3849628 DOI: 10.3389/fcimb.2013.00092] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 11/19/2013] [Indexed: 01/01/2023] Open
Abstract
For bacterial pathogens whose sole environmental reservoir is the human host, the acquisition of essential nutrients, particularly transition metals, is a critical aspect of survival due to tight sequestration and limitation strategies deployed to curtail pathogen outgrowth. As such, these bacteria have developed diverse, specialized acquisition mechanisms to obtain these metals from the niches of the body in which they reside. To oppose the spread of infection, the human host has evolved multiple mechanisms to counter bacterial invasion, including sequestering essential metals away from bacteria and exposing bacteria to lethal concentrations of metals. Hence, to maintain homeostasis within the host, pathogens must be able to acquire necessary metals from host proteins and to export such metals when concentrations become detrimental. Furthermore, this acquisition and efflux equilibrium must occur in a tissue-specific manner because the concentration of metals varies greatly within the various microenvironments of the human body. In this review, we examine the functional roles of the metal import and export systems of the Gram-positive pathogen Streptococcus pneumoniae in both signaling and pathogenesis.
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Affiliation(s)
- Erin S Honsa
- Department of Infectious Diseases, St. Jude Children's Research Hospital Memphis, TN, USA
| | - Michael D L Johnson
- Department of Infectious Diseases, St. Jude Children's Research Hospital Memphis, TN, USA
| | - Jason W Rosch
- Department of Infectious Diseases, St. Jude Children's Research Hospital Memphis, TN, USA
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21
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Miyaji EN, Oliveira MLS, Carvalho E, Ho PL. Serotype-independent pneumococcal vaccines. Cell Mol Life Sci 2013; 70:3303-26. [PMID: 23269437 PMCID: PMC11113425 DOI: 10.1007/s00018-012-1234-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 12/01/2012] [Accepted: 12/04/2012] [Indexed: 12/14/2022]
Abstract
Streptococcus pneumoniae remains an important cause of disease with high mortality and morbidity, especially in children and in the elderly. The widespread use of the polysaccharide conjugate vaccines in some countries has led to a significant decrease in invasive disease caused by vaccine serotypes, but an increase in disease caused by non-vaccine serotypes has impacted on the overall efficacy of these vaccines on pneumococcal disease. The obvious solution to overcome such shortcomings would be the development of new formulations that provide serotype-independent immunity. This review focuses on the most promising approaches, including protein antigens, whole cell pneumococcal vaccines, and recombinant bacteria expressing pneumococcal antigens. The protective capacity of these vaccine candidates against the different stages of pneumococcal infection, including colonization, mucosal disease, and invasive disease in animal models is reviewed. Some of the human trials that have already been performed or that are currently ongoing are presented. Finally, the feasibility and the possible shortcomings of these candidates in relation to an ideal vaccine against pneumococcal infections are discussed.
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Affiliation(s)
- Eliane Namie Miyaji
- Centro de Biotecnologia, Instituto Butantan, Av Vital Brasil 1500, São Paulo, SP 05503-900 Brazil
| | | | - Eneas Carvalho
- Centro de Biotecnologia, Instituto Butantan, Av Vital Brasil 1500, São Paulo, SP 05503-900 Brazil
| | - Paulo Lee Ho
- Centro de Biotecnologia, Instituto Butantan, Av Vital Brasil 1500, São Paulo, SP 05503-900 Brazil
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22
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Darrieux M, Goulart C, Briles D, Leite LCDC. Current status and perspectives on protein-based pneumococcal vaccines. Crit Rev Microbiol 2013; 41:190-200. [DOI: 10.3109/1040841x.2013.813902] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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23
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Olaya-Abril A, Jiménez-Munguía I, Gómez-Gascón L, Obando I, Rodríguez-Ortega MJ. Identification of potential new protein vaccine candidates through pan-surfomic analysis of pneumococcal clinical isolates from adults. PLoS One 2013; 8:e70365. [PMID: 23894641 PMCID: PMC3720901 DOI: 10.1371/journal.pone.0070365] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 06/17/2013] [Indexed: 11/23/2022] Open
Abstract
Purified polysaccharide and conjugate vaccines are widely used for preventing infections in adults and in children against the Gram-positive bacterium Streptococcus pneumoniae, a pathogen responsible for high morbidity and mortality rates, especially in developing countries. However, these polysaccharide-based vaccines have some important limitations, such as being serotype-dependent, being subjected to losing efficacy because of serotype replacement and high manufacturing complexity and cost. It is expected that protein-based vaccines will overcome these issues by conferring a broad coverage independent of serotype and lowering production costs. In this study, we have applied the “shaving” proteomic approach, consisting of the LC/MS/MS analysis of peptides generated by protease treatment of live cells, to a collection of 16 pneumococcal clinical isolates from adults, representing the most prevalent strains circulating in Spain during the last years. The set of unique proteins identified in all the isolates, called “pan-surfome”, consisted of 254 proteins, which included most of the protective protein antigens reported so far. In search of new candidates with vaccine potential, we identified 32 that were present in at least 50% of the clinical isolates analyzed. We selected four of them (Spr0012, Spr0328, Spr0561 and SP670_2141), whose protection capacity has not yet been tested, for assaying immunogenicity in human sera. All of them induced the production of IgM antibodies in infected patients, thus indicating that they could enter the pipeline for vaccine studies. The pan-surfomic approach shows its utility in the discovery of new proteins that can elicit protection against infectious microorganisms.
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Affiliation(s)
- Alfonso Olaya-Abril
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba; Campus de Excelencia Internacional CeiA3; Hospital Universitario Reina Sofía, Córdoba; Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba; and Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain
| | - Irene Jiménez-Munguía
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba; Campus de Excelencia Internacional CeiA3; Hospital Universitario Reina Sofía, Córdoba; Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba; and Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain
| | | | - Ignacio Obando
- Sección de Enfermedades Infecciosas Pediátricas e Inmunopatología, Hospital Universitario Infantil Virgen del Rocío, Sevilla, Spain
| | - Manuel J. Rodríguez-Ortega
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba; Campus de Excelencia Internacional CeiA3; Hospital Universitario Reina Sofía, Córdoba; Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba; and Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain
- * E-mail:
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Basavanna S, Chimalapati S, Maqbool A, Rubbo B, Yuste J, Wilson RJ, Hosie A, Ogunniyi AD, Paton JC, Thomas G, Brown JS. The effects of methionine acquisition and synthesis on Streptococcus pneumoniae growth and virulence. PLoS One 2013; 8:e49638. [PMID: 23349662 PMCID: PMC3551916 DOI: 10.1371/journal.pone.0049638] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 10/16/2012] [Indexed: 11/19/2022] Open
Abstract
Bacterial pathogens need to acquire nutrients from the host, but for many nutrients their importance during infection remain poorly understood. We have investigated the importance of methionine acquisition and synthesis for Streptococcus pneumoniae growth and virulence using strains with gene deletions affecting a putative methionine ABC transporter lipoprotein (Sp_0149, metQ) and/or methionine biosynthesis enzymes (Sp_0585 - Sp_0586, metE and metF). Immunoblot analysis confirmed MetQ was a lipoprotein and present in all S. pneumoniae strains investigated. However, vaccination with MetQ did not prevent fatal S. pneumoniae infection in mice despite stimulating a strong specific IgG response. Tryptophan fluorescence spectroscopy and isothermal titration calorimetry demonstrated that MetQ has both a high affinity and specificity for L-methionine with a KD of ∼25 nM, and a ΔmetQ strain had reduced uptake of C14-methionine. Growth of the ΔmetQ/ΔmetEF strain was greatly impaired in chemically defined medium containing low concentrations of methionine and in blood but was partially restored by addition of high concentrations of exogenous methionine. Mixed infection models showed no attenuation of the ΔmetQ, ΔmetEF and ΔmetQ/ΔmetEF strains in their ability to colonise the mouse nasopharnyx. In a mouse model of systemic infection although significant infection was established in all mice, there were reduced spleen bacterial CFU after infection with the ΔmetQ/ΔmetEF strain compared to the wild-type strain. These data demonstrate that Sp_0149 encodes a high affinity methionine ABC transporter lipoprotein and that Sp_0585 – Sp_0586 are likely to be required for methionine synthesis. Although Sp_0149 and Sp_0585-Sp_0586 make a contribution towards full virulence, neither was essential for S. pneumoniae survival during infection.
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Affiliation(s)
- Shilpa Basavanna
- Department of Microbiology and Molecular Genetics, University of Texas-Houston Medical School, Houston, Texas, United States of America
| | - Suneeta Chimalapati
- Department of Medicine, Centre for Inflammation and Tissue Repair, University College Medical School, Rayne Institute, London, United Kingdom
| | - Abbas Maqbool
- Department of Biology (Area 10), University of York, York, United Kingdom
| | - Bruna Rubbo
- Department of Medicine, Centre for Inflammation and Tissue Repair, University College Medical School, Rayne Institute, London, United Kingdom
| | - Jose Yuste
- Centro de Investigaciones Biologicas, CSIC and CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Robert J. Wilson
- Department of Medicine, Centre for Inflammation and Tissue Repair, University College Medical School, Rayne Institute, London, United Kingdom
| | - Arthur Hosie
- Division of Science, University of Bedfordshire, Park Square, Luton, Bedfordshire, United Kingdom
| | - Abiodun D. Ogunniyi
- Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, South Australia, Australia
| | - James C. Paton
- Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, South Australia, Australia
| | - Gavin Thomas
- Department of Biology (Area 10), University of York, York, United Kingdom
| | - Jeremy S. Brown
- Department of Medicine, Centre for Inflammation and Tissue Repair, University College Medical School, Rayne Institute, London, United Kingdom
- * E-mail:
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Experimental human pneumococcal carriage models for vaccine research. Trends Microbiol 2011; 19:464-70. [DOI: 10.1016/j.tim.2011.06.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 06/02/2011] [Accepted: 06/13/2011] [Indexed: 01/14/2023]
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26
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Moffitt KL, Malley R. Next generation pneumococcal vaccines. Curr Opin Immunol 2011; 23:407-13. [PMID: 21514128 DOI: 10.1016/j.coi.2011.04.002] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 04/01/2011] [Accepted: 04/04/2011] [Indexed: 11/15/2022]
Abstract
Currently licensed pneumococcal vaccines are based on the generation of antibodies to the pneumococcal polysaccharide, of which there are more than 90 different types. While these vaccines are highly effective against the serotypes included, their high cost and limited serotype coverage limit their usefulness worldwide, particularly in low resource areas. Thus alternative or adjunctive options are being actively pursued. This review will present these various approaches, including variations of the polysaccharide-protein conjugate strategy, protein-based strategies, and whole cell pneumococcal vaccines. The immunological basis for these different approaches is discussed as well.
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Affiliation(s)
- Kristin L Moffitt
- Division of Infectious Diseases, Children's Hospital, Harvard Medical School, Boston, MA, United States
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27
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Ge X, Kitten T, Munro CL, Conrad DH, Xu P. Pooled protein immunization for identification of cell surface antigens in Streptococcus sanguinis. PLoS One 2010; 5:e11666. [PMID: 20668678 PMCID: PMC2909906 DOI: 10.1371/journal.pone.0011666] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2010] [Accepted: 06/21/2010] [Indexed: 02/04/2023] Open
Abstract
Background Available bacterial genomes provide opportunities for screening vaccines by reverse vaccinology. Efficient identification of surface antigens is required to reduce time and animal cost in this technology. We developed an approach to identify surface antigens rapidly in Streptococcus sanguinis, a common infective endocarditis causative species. Methods and Findings We applied bioinformatics for antigen prediction and pooled antigens for immunization. Forty-seven surface-exposed proteins including 28 lipoproteins and 19 cell wall-anchored proteins were chosen based on computer algorithms and comparative genomic analyses. Eight proteins among these candidates and 2 other proteins were pooled together to immunize rabbits. The antiserum reacted strongly with each protein and with S. sanguinis whole cells. Affinity chromatography was used to purify the antibodies to 9 of the antigen pool components. Competitive ELISA and FACS results indicated that these 9 proteins were exposed on S. sanguinis cell surfaces. The purified antibodies had demonstrable opsonic activity. Conclusions The results indicate that immunization with pooled proteins, in combination with affinity purification, and comprehensive immunological assays may facilitate cell surface antigen identification to combat infectious diseases.
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Affiliation(s)
- Xiuchun Ge
- Philips Institute of Oral and Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Todd Kitten
- Philips Institute of Oral and Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Cindy L. Munro
- Department of Adult Health Nursing, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Daniel H. Conrad
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Ping Xu
- Philips Institute of Oral and Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- * E-mail:
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Carlson PE, Dixon SD, Janes BK, Carr KA, Nusca TD, Anderson EC, Keene SE, Sherman DH, Hanna PC. Genetic analysis of petrobactin transport in Bacillus anthracis. Mol Microbiol 2010; 75:900-9. [PMID: 20487286 DOI: 10.1111/j.1365-2958.2009.07025.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Iron acquisition mechanisms play an important role in the pathogenesis of many infectious microbes. In Bacillus anthracis, the siderophore petrobactin is required for both growth in iron-depleted conditions and for full virulence of the bacterium. Here we demonstrate the roles of two putative petrobactin binding proteins FatB and FpuA (encoded by GBAA5330 and GBAA4766 respectively) in B. anthracis iron acquisition and pathogenesis. Markerless deletion mutants were created using allelic exchange. The Delta fatB strain was capable of wild-type levels of growth in iron-depleted conditions, indicating that FatB does not play an essential role in petrobactin uptake. In contrast, Delta fpuA bacteria exhibited a significant decrease in growth under low-iron conditions when compared with wild-type bacteria. This mutant could not be rescued by the addition of exogenous purified petrobactin. Further examination of this strain demonstrated increased levels of petrobactin accumulation in the culture supernatants, suggesting no defect in siderophore synthesis or export but, instead, an inability of Delta fpuA to import this siderophore. Delta fpuA spores were also significantly attenuated in a murine model of inhalational anthrax. These results provide the first genetic evidence demonstrating the role of FpuA in petrobactin uptake.
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Affiliation(s)
- Paul E Carlson
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48104, USA
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29
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Genetic immunization with the immunodominant antigen P48 of Mycoplasma agalactiae stimulates a mixed adaptive immune response in BALBc mice. Res Vet Sci 2008; 86:414-20. [PMID: 19007952 DOI: 10.1016/j.rvsc.2008.09.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 09/16/2008] [Accepted: 09/29/2008] [Indexed: 11/22/2022]
Abstract
A DNA vaccine against contagious agalactia was developed for the first time, encoding the P48 of Mycoplasma agalactiae. Specific immune responses elicited in BALB/c mice were evaluated. Both total IgG and IgG1 were detected in mice vaccinated with pVAX1/P48. Proliferation of mononuclear cells of the spleen, levels of gamma interferon, interleukin-12, and interleukin-2 mRNAs were enhanced in immunized animals. Results indicate that pVAX1/P48 vaccination induced both T(h)1 and T(h)2 immune responses. Nucleic acid immunization could be a new strategy against M. agalactiae infections and may be potentially used to develop vaccines for other Mycoplasma diseases.
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30
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Cao J, Chen T, Li D, Wong CK, Chen D, Xu W, Zhang X, Lam CW, Yin Y. Mucosal immunization with purified ClpP could elicit protective efficacy against pneumococcal pneumonia and sepsis in mice. Microbes Infect 2008; 10:1536-42. [DOI: 10.1016/j.micinf.2008.09.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Revised: 07/18/2008] [Accepted: 09/15/2008] [Indexed: 10/21/2022]
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Impaired opsonization with C3b and phagocytosis of Streptococcus pneumoniae in sera from subjects with defects in the classical complement pathway. Infect Immun 2008; 76:3761-70. [PMID: 18541650 DOI: 10.1128/iai.00291-08] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Results from studies using mice deficient in specific complement factors and clinical data on patients with an inherited deficiency of the classical complement pathway component C2 suggest that the classical pathway is vital for immunity to Streptococcus pneumoniae. However, the consequences of defects in classical pathway activity for opsonization with C3b and the phagocytosis of different S. pneumoniae serotypes in human serum are not known, and there has not been a systematic analysis of the abilities of sera from subjects with a C2 deficiency to opsonize S. pneumoniae. Hence, to investigate the role of the classical pathway in immunity to S. pneumoniae in more detail, flow cytometry assays of opsonization with C3b and the phagocytosis of three capsular serotypes of S. pneumoniae were performed using human sera depleted of the complement factor C1q or B or sera obtained from C2-deficient subjects. The results demonstrate that, in human serum, the classical pathway is vital for C3b-iC3b deposition onto cells of all three serotypes of S. pneumoniae and seems to be more important than the alternative pathway for phagocytosis. Compared to the results for sera from normal subjects, C3b-iC3b deposition and total anti-S. pneumoniae antibody activity levels in sera obtained from C2(-/-) subjects were reduced and the efficiency of phagocytosis of all three S. pneumoniae strains was impaired. Anticapsular antibody levels did not correlate with phagocytosis or C3b-iC3b deposition. These data confirm that the classical pathway is vital for complement-mediated phagocytosis of S. pneumoniae and demonstrate why subjects with a C2 deficiency have a marked increase in susceptibility to S. pneumoniae infections.
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Glanfield A, McManus DP, Anderson GJ, Jones MK. Pumping iron: a potential target for novel therapeutics against schistosomes. Trends Parasitol 2007; 23:583-8. [PMID: 17962074 PMCID: PMC2756500 DOI: 10.1016/j.pt.2007.08.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Revised: 02/13/2007] [Accepted: 08/06/2007] [Indexed: 11/17/2022]
Abstract
Parasites, as with the vast majority of organisms, are dependent on iron. Pathogens must compete directly with the host for this essential trace metal, which is sequestered within host proteins and inorganic chelates. Not surprisingly, pathogenic prokaryotes and eukaryotic parasites have diverse adaptations to exploit host iron resources. How pathogenic bacteria scavenge host iron is well characterized and is reasonably well known for a few parasitic protozoa, but is poorly understood for metazoan parasites. Strategies of iron acquisition by schistosomes are examined here, with emphasis on possible mechanisms of iron absorption from host serum iron transporters or from digested haem. Elucidation of these metabolic mechanisms could lead to the development of new interventions for the control of schistosomiasis and other helminth diseases.
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Affiliation(s)
- Amber Glanfield
- Division of Infectious Diseases and Immunology, The Queensland Institute of Medical Research, 300 Herston Road, Herston, Queensland 4006, Australia.
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Pretorius A, Collins NE, Steyn HC, van Strijp F, van Kleef M, Allsopp BA. Protection against heartwater by DNA immunisation with four Ehrlichia ruminantium open reading frames. Vaccine 2007; 25:2316-24. [PMID: 17224211 DOI: 10.1016/j.vaccine.2006.11.061] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2006] [Revised: 11/22/2006] [Accepted: 11/28/2006] [Indexed: 11/22/2022]
Abstract
We have reported previously that a recombinant DNA vaccine consisting of four Ehrlichia ruminantium (Welgevonden) open reading frames (ORFs) known as the 1H12 cocktail provided protection against a virulent E. ruminantium (Welgevonden) needle challenge in sheep. In this study, we have investigated the vaccine effectiveness of two other cocktails of E. ruminantium (Welgevonden) ORFs, as well as single ORFs from the 1H12 cocktail, to protect sheep against a virulent needle challenge with the homologous strain. Each individual 1H12 ORF provided protection, but all the animals vaccinated with the other cocktails succumbed to the challenge.
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Affiliation(s)
- A Pretorius
- Onderstepoort Veterinary Institute, Private Bag X5, Onderstepoort 0110, South Africa.
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