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Di Azevedo MIN, Borges ALDSB, Kremer F, de Melo JDSL, Carvalho-Costa FA, Lilenbaum W. Genetic Analysis of LigA, LipL32, Loa22, and OmpL1 Antigens from Leptospira spp. Sejroe Serogroup: How Close We Are To a Vaccine Against Bovine Leptospirosis? Curr Microbiol 2023; 80:310. [PMID: 37535179 DOI: 10.1007/s00284-023-03414-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 07/12/2023] [Indexed: 08/04/2023]
Abstract
Bovine leptospirosis has as main causative agents Leptospira spp. from Sejroe serogroup. Vaccination is a crucial step to control this infection. The use of conserved proteins among Leptospira spp. is of great importance for a protective immune response. The aim of the present study is to genetically analyze antigens of Leptospira spp. from Sejroe serogroup strains isolated from cattle for a preliminary evaluation of vaccine candidates. Genes associated with antigenicity-LigA, LipL32, Loa22, and OmpL1-were analyzed through bioinformatic and immunoinformatic tools. Despite high diversity observed in strains, on an amino acid level, highly conserved regions were observed (> 90%), particularly in LipL32 gene. Moreover, highly conserved amino acid regions (> 30 aa) were observed in all genes, regardless of species, geographical origin or biological source of isolation. Superposed structures of protein fragments including all the predicted MHC-II and B-Cell epitopes were demonstrated. Results presented herein are preliminary, but a fundamental step towards the development of an efficient vaccine against bovine leptospirosis, a silent but enormously concerning disease.
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Affiliation(s)
| | | | - Frederico Kremer
- Technological Development Center, Federal University of Pelotas, Capão do Leão, Rio Grande do Sul, Brazil
| | | | - Filipe Anibal Carvalho-Costa
- Laboratory of Epidemiology and Molecular Systematics, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Walter Lilenbaum
- Laboratory of Veterinary Bacteriology, Fluminense Federal University, Biomedical Institute, Niterói, Rio de Janeiro, Brazil
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de Oliveira NR, Santos FDS, Dos Santos VAC, Maia MAC, Oliveira TL, Dellagostin OA. Challenges and Strategies for Developing Recombinant Vaccines against Leptospirosis: Role of Expression Platforms and Adjuvants in Achieving Protective Efficacy. Pathogens 2023; 12:787. [PMID: 37375478 DOI: 10.3390/pathogens12060787] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/29/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
The first leptospiral recombinant vaccine was developed in the late 1990s. Since then, progress in the fields of reverse vaccinology (RV) and structural vaccinology (SV) has significantly improved the identification of novel surface-exposed and conserved vaccine targets. However, developing recombinant vaccines for leptospirosis faces various challenges, including selecting the ideal expression platform or delivery system, assessing immunogenicity, selecting adjuvants, establishing vaccine formulation, demonstrating protective efficacy against lethal disease in homologous challenge, achieving full renal clearance using experimental models, and reproducibility of protective efficacy against heterologous challenge. In this review, we highlight the role of the expression/delivery system employed in studies based on the well-known LipL32 and leptospiral immunoglobulin-like (Lig) proteins, as well as the choice of adjuvants, as key factors to achieving the best vaccine performance in terms of protective efficacy against lethal infection and induction of sterile immunity.
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Affiliation(s)
- Natasha Rodrigues de Oliveira
- Núcleo de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas 96010-610, RS, Brazil
| | - Francisco Denis Souza Santos
- Núcleo de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas 96010-610, RS, Brazil
| | | | - Mara Andrade Colares Maia
- Núcleo de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas 96010-610, RS, Brazil
| | - Thaís Larré Oliveira
- Núcleo de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas 96010-610, RS, Brazil
| | - Odir Antônio Dellagostin
- Núcleo de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas 96010-610, RS, Brazil
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3
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Analysis of LruC lipoprotein and identification of peptides candidates for vaccine development and diagnosis of leptospirosis. PLoS One 2023; 18:e0281344. [PMID: 36745643 PMCID: PMC9901810 DOI: 10.1371/journal.pone.0281344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 01/20/2023] [Indexed: 02/07/2023] Open
Abstract
Leptospirosis is a public health concern with lethality around 15% of the total cases. The current vaccines against Leptospira infection based on bacterins have several limitations, which require urgent development of new ones. In this context, groundbreaking approaches such as peptide-vaccines could be used to come around with promising results. Our goal was to identify conserved and immunogenic epitopes from the lipoprotein LruC that could interact with Major Histocompatibility Complex (MHC) I and II. LruC is a conserved lipoprotein expressed during leptospirosis that is considered among vaccine candidates and can be used as source for development of peptide-based vaccines. We searched for peptides that would be recognized by antibodies from either serum of hamsters previously immunized with low-LPS bacterin vaccines or from serum of patients diagnosed with leptospirosis. Immuno properties of seven peptides from LruC protein were evaluated in silico and by Dot Blot assay, and validate by ELISA. Preliminary results pointed one promising peptide that was recognized by the sera. In conclusion, the immunoinformatic approach helps the search and screening of peptides, while the Dot Blot assay, a simple and effective tool, helps to test and validate them. Thus, these prospective techniques together were validated to identify and validate potential peptides for further investigation as peptide-based vaccines or diagnostic methods.
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Govindan P, Manjusha P, Saravanan KM, Natesan V, Salmen SH, Alfarraj S, Wainwright M, Shakila H. RETRACTED ARTICLE: Expression and preliminary characterization of the potential vaccine candidate LipL32 of leptospirosis. APPLIED NANOSCIENCE 2023; 13:1801. [PMID: 34608427 PMCID: PMC8483425 DOI: 10.1007/s13204-021-02097-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/09/2021] [Indexed: 12/11/2022]
Affiliation(s)
- Pothiaraj Govindan
- grid.10214.360000 0001 2186 7912Department of Molecular Microbiology, School of Biotechnology, Madurai Kamaraj University, Madurai-21, Tamil Nadu India
| | - Packiyadass Manjusha
- grid.10214.360000 0001 2186 7912Department of Molecular Microbiology, School of Biotechnology, Madurai Kamaraj University, Madurai-21, Tamil Nadu India
| | - Konda Mani Saravanan
- Scigen Research and Innovation Pvt Ltd, Periyar Technology Business Incubator, Thanjavur, Tamil Nadu 613403 India
| | - Vijayakumar Natesan
- grid.411408.80000 0001 2369 7742Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University, Annamalainagar, Chidambaram, Tamil Nadu 608002 India
| | - Saleh H. Salmen
- grid.56302.320000 0004 1773 5396Department of Botany and Microbiology, College of Science, King Saud University, PO Box -2455, Riyadh, 11451 Saudi Arabia
| | - Saleh Alfarraj
- grid.56302.320000 0004 1773 5396Zoology Department, College of Science, King Saud University, Riyadh, 11451 Saudi Arabia
| | - Milton Wainwright
- grid.11835.3e0000 0004 1936 9262Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN UK
| | - Harshavardhan Shakila
- grid.10214.360000 0001 2186 7912Department of Molecular Microbiology, School of Biotechnology, Madurai Kamaraj University, Madurai-21, Tamil Nadu India
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A New Recombinant Multiepitope Chimeric Protein of Leptospira interrogans Is a Promising Marker for the Serodiagnosis of Leptospirosis. Trop Med Infect Dis 2022; 7:tropicalmed7110362. [DOI: 10.3390/tropicalmed7110362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/20/2022] [Accepted: 11/02/2022] [Indexed: 11/11/2022] Open
Abstract
The zoonotic disease leptospirosis is caused by pathogenic species of the genus Leptospira and was recently included in the list of Neglected Diseases by the World Health Organization. Leptospirosis burden is estimated to have over a million human cases and cause 60 thousand deaths annually, in addition to its economic impact and veterinary concern. The microscopic agglutination test (MAT), recommended by the World Health Organization, exhibits reduced sensitivity at the beginning of the disease, in addition to being technically difficult. New recombinant antigens are being pursued for rapid and specific serodiagnostic tests, especially in the initial phase of the disease, and chimeric multiepitope proteins are a strategy with a great potential to be implemented in serology. Based on previous subproteomic results, we designed a synthetic construct comprising 10 conserved leptospiral surface antigens, and the recombinant protein was purified and evaluated regarding its diagnostic potential. The protein termed rChi2 was recognized by antibodies in serum from patients both at the onset (MAT−) and in the convalescent (MAT+) phase in 75 and 82% of responders, respectively. In addition, rChi2 immunization in hamsters elicited a strong humoral response, and anti-rChi2 antibodies recognized several immobilized intact Leptospira species, validating its potential as an early, broad, and cross-reactive diagnostic test.
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Techawiwattanaboon T, Courant T, Brunner L, Sathean-anan-kun S, Krangvichian P, Iadsee N, Nakornpakdee Y, Sangjun N, Komanee P, Collin N, Ruxrungtham K, Patarakul K. Designing Adjuvant Formulations to Promote Immunogenicity and Protective Efficacy of Leptospira Immunoglobulin-Like Protein A Subunit Vaccine. Front Cell Infect Microbiol 2022; 12:918629. [PMID: 35782116 PMCID: PMC9243587 DOI: 10.3389/fcimb.2022.918629] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 05/17/2022] [Indexed: 11/23/2022] Open
Abstract
The leptospirosis burden on humans, especially in high-risk occupational groups and livestock, leads to public health and economic problems. Leptospirosis subunit vaccines have been under development and require further improvement to provide complete protection. Adjuvants can be used to enhance the amplitude, quality, and durability of immune responses. Previously, we demonstrated that LMQ adjuvant (neutral liposomes containing monophosphoryl lipid A (MPL) and Quillaja saponaria derived QS21 saponin) promoted protective efficacy of LigAc vaccine against Leptospira challenge. To promote immunogenicity and protective efficacy of the subunit vaccines, three alternative adjuvants based on neutral liposomes or squalene-in-water emulsion were evaluated in this study. LQ and LQuil adjuvants combined the neutral liposomes with the QS21 saponin or Quillaja saponaria derived QuilA® saponin, respectively. SQuil adjuvant combined a squalene-in-water emulsion with the QuilA® saponin. The immunogenicity and protective efficacy of LigAc (20 µg) formulated with the candidate adjuvants were conducted in golden Syrian hamsters. Hamsters were vaccinated three times at a 2-week interval, followed by a homologous challenge of L. interrogans serovar Pomona. The results showed that LigAc combined with LQ, LQuil, or SQuil adjuvants conferred substantial antibody responses and protective efficacy (survival rate, pathological change, and Leptospira renal colonization) comparable to LMQ adjuvant. The LigAc+LQ formulation conferred 62.5% survival but was not significantly different from LigAc+LMQ, LigAc+LQuil, and LigAc+SQuil formulations (50% survival). This study highlights the potential of saponin-containing adjuvants LMQ, LQ, LQuil, and SQuil for both human and animal leptospirosis vaccines.
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Affiliation(s)
- Teerasit Techawiwattanaboon
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Bangkok, Thailand
| | - Thomas Courant
- Vaccine Formulation Institute, Plan-Les-Ouates, Switzerland
| | - Livia Brunner
- Vaccine Formulation Institute, Plan-Les-Ouates, Switzerland
| | - Suwitra Sathean-anan-kun
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Bangkok, Thailand
| | - Pratomporn Krangvichian
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Bangkok, Thailand
- Medical Microbiology, Interdisciplinary Program, Graduate School, Chulalongkorn University, Bangkok, Thailand
| | - Nutta Iadsee
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Bangkok, Thailand
- Medical Microbiology, Interdisciplinary Program, Graduate School, Chulalongkorn University, Bangkok, Thailand
| | - Yaowarin Nakornpakdee
- Department of Pathobiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Noppadon Sangjun
- Laboratory Animal Section, Analysis Division, Armed Force Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | - Pat Komanee
- Laboratory Animal Section, Analysis Division, Armed Force Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | - Nicolas Collin
- Vaccine Formulation Institute, Plan-Les-Ouates, Switzerland
| | - Kiat Ruxrungtham
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Bangkok, Thailand
| | - Kanitha Patarakul
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Bangkok, Thailand
- *Correspondence: Kanitha Patarakul, ;
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7
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Deenin W, Yakoh A, Kreangkaiwal C, Chailapakul O, Patarakul K, Chaiyo S. Integrated Lateral Flow Electrochemical Strip for Leptospirosis Diagnosis. Anal Chem 2022; 94:2554-2560. [PMID: 35089007 DOI: 10.1021/acs.analchem.1c04440] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
LipL32 is an outer membrane protein present only on pathogenic Leptospira species, which is the causative agent of leptospirosis. Leptospirosis symptoms are often misdiagnosed with other febrile illnesses as the clinical manifestations are non-specific. Therefore, an accurate diagnostic tool for leptospirosis is indeed critical for proper and prompt treatment. Typical diagnosis via serological assays is generally performed to assess the antibodies produced against Leptospira. However, their delayed antibody response and complicated procedure undoubtedly limit the practical utilization especially in a primary care setting. Here, we demonstrate for the first time an early-stage detection of LipL32 by an integrated lateral-flow immunoassay with an electrochemical readout (eLFIA). A ferrocene trace tag was monitored via differential pulse voltammetry operated on a smartphone-based device, thus allowing for on-field testing. A superior performance in terms of the lowest detectable limit of detection of 8.53 pg/mL and broad linear dynamic range (5 orders of magnitude) among other sensors available thus far was established. Additionally, the developed test strip provided a straightforward yet sensitive approach for diagnosis of leptospirosis using the collected human sera from patients, in which the results were comparable to the real-time polymerase chain reaction technique.
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Affiliation(s)
- Wanwisa Deenin
- Program in Biotechnology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.,Institute of Biotechnology and Genetic Engineering, Chulalongkorn University, Bangkok 10330, Thailand
| | - Abdulhadee Yakoh
- Institute of Biotechnology and Genetic Engineering, Chulalongkorn University, Bangkok 10330, Thailand.,Electrochemistry and Optical Spectroscopy Center of Excellence (EOSCE), Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Chahya Kreangkaiwal
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
| | - Orawon Chailapakul
- Electrochemistry and Optical Spectroscopy Center of Excellence (EOSCE), Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Kanitha Patarakul
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
| | - Sudkate Chaiyo
- Institute of Biotechnology and Genetic Engineering, Chulalongkorn University, Bangkok 10330, Thailand.,Electrochemistry and Optical Spectroscopy Center of Excellence (EOSCE), Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.,Food Risk Hub, Research Unit of Chulalongkorn University, Bangkok 10330, Thailand
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Wunder EA, Adhikarla H, Hamond C, Owers Bonner KA, Liang L, Rodrigues CB, Bisht V, Nally JE, Alt DP, Reis MG, Diggle PJ, Felgner PL, Ko A. A live attenuated-vaccine model confers cross-protective immunity against different species of the Leptospira genus. eLife 2021; 10:e64166. [PMID: 33496263 PMCID: PMC7837694 DOI: 10.7554/elife.64166] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 12/23/2020] [Indexed: 12/24/2022] Open
Abstract
Leptospirosis is the leading zoonotic disease in terms of morbidity and mortality worldwide. Effective prevention is urgently needed as the drivers of disease transmission continue to intensify. The key challenge has been developing a widely applicable vaccine that protects against the >300 serovars that can cause leptospirosis. Live attenuated mutants are enticing vaccine candidates and poorly explored in the field. We evaluated a recently characterized motility-deficient mutant lacking the expression of a flagellar protein, FcpA. Although the fcpA- mutant has lost its ability to cause disease, transient bacteremia was observed. In two animal models, immunization with a single dose of the fcpA- mutant was sufficient to induce a robust anti-protein antibodies response that promoted protection against infection with different pathogenic Leptospira species. Furthermore, characterization of the immune response identified a small repertoire of biologically relevant proteins that are highly conserved among pathogenic Leptospira species and potential correlates of cross-protective immunity.
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Affiliation(s)
- Elsio A Wunder
- Department of Epidemiology of Microbial Diseases; Yale School of Public HealthNew HavenUnited States
- Gonçalo Moniz Institute, Oswaldo Cruz Foundation; Brazilian Ministry of HealthSalvadorBrazil
| | - Haritha Adhikarla
- Department of Epidemiology of Microbial Diseases; Yale School of Public HealthNew HavenUnited States
| | - Camila Hamond
- Department of Epidemiology of Microbial Diseases; Yale School of Public HealthNew HavenUnited States
| | - Katharine A Owers Bonner
- Department of Epidemiology of Microbial Diseases; Yale School of Public HealthNew HavenUnited States
| | - Li Liang
- Department of Medicine, Division of Infectious Disease; University of California IrvineIrvineUnited States
| | - Camila B Rodrigues
- Department of Medicine, Division of Infectious Disease; University of California IrvineIrvineUnited States
- Institute of Technology in Immunobiology, Oswaldo Cruz Foundation; Brazilian Ministry of HealthRio de JaneiroBrazil
| | - Vimla Bisht
- Department of Epidemiology of Microbial Diseases; Yale School of Public HealthNew HavenUnited States
| | - Jarlath E Nally
- Infectious Bacterial Diseases Research Unit, National Animal Disease Center, Agricultural Research Service; United States Department of AgricultureAmesUnited States
| | - David P Alt
- Infectious Bacterial Diseases Research Unit, National Animal Disease Center, Agricultural Research Service; United States Department of AgricultureAmesUnited States
| | - Mitermayer G Reis
- Gonçalo Moniz Institute, Oswaldo Cruz Foundation; Brazilian Ministry of HealthSalvadorBrazil
| | - Peter J Diggle
- CHICAS, Lancaster Medical School; Lancaster UniversityLancasterUnited Kingdom
| | - Philip L Felgner
- Department of Medicine, Division of Infectious Disease; University of California IrvineIrvineUnited States
| | - Albert Ko
- Department of Epidemiology of Microbial Diseases; Yale School of Public HealthNew HavenUnited States
- Gonçalo Moniz Institute, Oswaldo Cruz Foundation; Brazilian Ministry of HealthSalvadorBrazil
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Haake DA, Matsunaga J. Leptospiral Immunoglobulin-Like Domain Proteins: Roles in Virulence and Immunity. Front Immunol 2021; 11:579907. [PMID: 33488581 PMCID: PMC7821625 DOI: 10.3389/fimmu.2020.579907] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 11/05/2020] [Indexed: 02/03/2023] Open
Abstract
The virulence mechanisms required for infection and evasion of immunity by pathogenic Leptospira species remain poorly understood. A number of L. interrogans surface proteins have been discovered, lying at the interface between the pathogen and host. Among these proteins, the functional properties of the Lig (leptospiral immunoglobulin-like domain) proteins have been examined most thoroughly. LigA, LigB, and LigC contain a series of, 13, 12, and 12 closely related domains, respectively, each containing a bacterial immunoglobulin (Big) -like fold. The multidomain region forms a mostly elongated structure that exposes a large surface area. Leptospires wield the Lig proteins to promote interactions with a range of specific host proteins, including those that aid evasion of innate immune mechanisms. These diverse binding events mediate adhesion of L. interrogans to the extracellular matrix, inhibit hemostasis, and inactivate key complement proteins. These interactions may help L. interrogans overcome the physical, hematological, and immunological barriers that would otherwise prevent the spirochete from establishing a systemic infection. Despite significant differences in the affinities of the LigA and LigB proteins for host targets, their functions overlap during lethal infection of hamsters; virulence is lost only when both ligA and ligB transcription is knocked down simultaneously. Lig proteins have been shown to be promising vaccine antigens through evaluation of a variety of different adjuvant strategies. This review serves to summarize current knowledge of Lig protein roles in virulence and immunity and to identify directions needed to better understand the precise functions of the Lig proteins during infection.
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Affiliation(s)
- David A. Haake
- Division of Infectious Diseases, VA Greater Los Angeles Healthcare System, Los Angeles, CA, United States
- Departments of Medicine, and Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, United States
| | - James Matsunaga
- Research Service, VA Greater Los Angeles Healthcare System, Los Angeles, CA, United States
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, United States
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A Comparison of Intramuscular and Subcutaneous Administration of LigA Subunit Vaccine Adjuvanted with Neutral Liposomal Formulation Containing Monophosphoryl Lipid A and QS21. Vaccines (Basel) 2020; 8:vaccines8030494. [PMID: 32882903 PMCID: PMC7565420 DOI: 10.3390/vaccines8030494] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 08/28/2020] [Accepted: 08/28/2020] [Indexed: 01/04/2023] Open
Abstract
Leptospirosis vaccines with higher potency and reduced adverse effects are needed for human use. The carboxyl terminal domain of leptospiral immunoglobulin like protein A (LigAc) is currently the most promising candidate antigen for leptospirosis subunit vaccine. However, LigAc-based vaccines were unable to confer sterilizing immunity against Leptospira infection in animal models. Several factors including antigen properties, adjuvant, delivery system, and administration route need optimization to maximize vaccine efficacy. Our previous report demonstrated protective effects of the recombinant LigAc (rLigAc) formulated with liposome-based adjuvant, called LMQ (neutral liposome combined with monophosphoryl lipid A and Quillaja saponaria fraction 21) in hamsters. This study aimed to evaluate the impact of two commonly used administration routes, intramuscular (IM) and subcutaneous (SC), on immunogenicity and protective efficacy of rLigAc-LMQ administrated three times at 2-week interval. Two IM vaccinations triggered significantly higher levels of total anti-rLigAc IgG than two SC injections. However, comparable IgG titers and IgG2/IgG1 ratio was observed for both routes after the third immunization. The route of vaccine administration did not influence the survival rate (60%) and renal colonization against lethal Leptospira challenge. Importantly, the kidneys of IM group showed no pathological lesions while the SC group showed mild damage. In conclusion, IM vaccination with rLigAc-LMQ not only elicited faster antibody production but also protected from kidney damage following leptospiral infection better than SC immunization. However, both tested routes did not influence protective efficacy in terms of survival rate and the level of renal colonization.
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Lauretti-Ferreira F, Silva PLD, Alcântara NM, Silva BF, Grabher I, Souza GO, Nakajima E, Akamatsu MA, Vasconcellos SA, Abreu PAE, Carvalho E, Martins EAL, Ho PL, da Silva JB. New strategies for Leptospira vaccine development based on LPS removal. PLoS One 2020; 15:e0230460. [PMID: 32218590 PMCID: PMC7100938 DOI: 10.1371/journal.pone.0230460] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 03/01/2020] [Indexed: 12/29/2022] Open
Abstract
Pathogenic spirochetes from genus Leptospira are etiologic agents of leptospirosis. Cellular vaccines against Leptospira infection often elicit mainly response against the LPS antigen of the serovars present in the formulation. There is no suitable protein candidate capable of replacing whole-cell vaccines, thus requiring new approaches on vaccine development to improve leptospirosis prevention. Our goal was to develop a whole-cell vaccine sorovar-independent based on LPS removal and conservation of protein antigens exposure, to evaluate the protective capacity of monovalent or bivalent vaccines against homologous and heterologous virulent Leptospira in hamster. Leptospire were subjected to heat inactivation, or to LPS extraction with butanol and in some cases further inactivation with formaldehyde. Hamsters were immunized and challenged with homologous or heterologous virulent serovars, blood and organs were collected from the survivors for bacterial quantification, chemokine evaluation, and analysis of sera antibody reactivity and cross-reactivity by Western blot. Immunization with either heated or low LPS vaccines with serovar Copenhageni or Canicola resulted in 100% protection of the animals challenged with homologous virulent bacteria. Notably, different from the whole-cell vaccine, the low LPS vaccines produced with serovar Canicola provided only partial protection in heterologous challenge with the virulent Copenhageni serovar. Immunization with bivalent formulation results in 100% protection of immunized animals challenged with virulent serovar Canicola. All vaccines produced were able to eliminate bacteria from the kidney of challenged animals. All the vaccines raised antibodies capable to recognize antigens of serovars not present in the vaccine formulation. Transcripts of IFNγ, CXCL16, CCL5, CXCL10, CXCR6, and CCR5, increased in all immunized animals. Conclusion: Our results showed that bivalent vaccines with reduced LPS may be an interesting strategy for protection against heterologous virulent serovars. Besides the desirable multivalent protection, the low LPS vaccines are specially promising due to the expected lower reatogenicity.
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Affiliation(s)
- Fabiana Lauretti-Ferreira
- Bioindustrial Division, Butantan Institute, São Paulo, Brazil
- Laboratory of Bacteriology, Butantan Institute, São Paulo, Brazil
| | | | | | - Bruna F. Silva
- Laboratory of Bacteriology, Butantan Institute, São Paulo, Brazil
| | - Isabele Grabher
- Laboratory of Bacteriology, Butantan Institute, São Paulo, Brazil
| | - Gisele O. Souza
- Laboratory of Bacterial Zoonosis, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil
| | - Erika Nakajima
- Laboratory of Process Development, Butantan Institute, São Paulo, Brazil
| | | | - Silvio A. Vasconcellos
- Laboratory of Bacterial Zoonosis, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil
| | | | - Eneas Carvalho
- Laboratory of Bacteriology, Butantan Institute, São Paulo, Brazil
| | | | - Paulo L. Ho
- Bioindustrial Division, Butantan Institute, São Paulo, Brazil
| | - Josefa B. da Silva
- Laboratory of Bacteriology, Butantan Institute, São Paulo, Brazil
- * E-mail:
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12
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Suphatpahirapol C, Nguyen TH, Tansiri Y, Yingchutrakul Y, Roytrakul S, Nitipan S, Wajjwalku W, Haltrich D, Prapong S, Keawsompong S. Expression of a leptospiral leucine-rich repeat protein using a food-grade vector in Lactobacillus plantarum, as a strategy for vaccine delivery. 3 Biotech 2019; 9:324. [PMID: 31406646 DOI: 10.1007/s13205-019-1856-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 08/01/2019] [Indexed: 01/05/2023] Open
Abstract
In this study, a first food-grade mucosal vaccine against leptospirosis was developed without the use of antibiotic resistance gene. This expression system is based on a food-grade host/vector system of Lactobacillus plantarum and a new vaccine candidate antigen, a leucine-rich repeat (LRR) protein of Leptospira borgpetersenii. The LRR of interest from serovar Sejroe is encoded by two overlapping genes and these genes were fused together by site-directed mutagenesis. The mutant gene thus obtained could be successfully expressed in this system as was shown by western blot analysis and liquid chromatography-mass spectrometry (LC-MS/MS) analysis. In addition, this analysis showed that the mutant LRR protein fused to a homologous signal peptide of L. plantarum could be exported to the cell surface as a result of the native LPXAG motif of the heterologous LRR protein, which presumably is responsible for anchoring the protein to the cell wall of L. plantarum. This new strategy could be an essential tool for further studies of leptospirosis mucosal vaccine delivery.
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Affiliation(s)
- Chattip Suphatpahirapol
- 1Interdisciplinary Graduate Program in Genetic Engineering, Graduate School, Kasetsart University, Bangkok, Thailand
- 2Department of Physiology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand
| | - Thu-Ha Nguyen
- 3Department of Food Sciences and Technology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Yada Tansiri
- 2Department of Physiology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand
- 4Center for Advanced Studies for Agriculture and Food (CASAF), Institute for Advanced Studies, Kasetsart University, Bangkok, Thailand
| | - Yodying Yingchutrakul
- 5National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency, Pathum Thani, Thailand
| | - Sittiruk Roytrakul
- 1Interdisciplinary Graduate Program in Genetic Engineering, Graduate School, Kasetsart University, Bangkok, Thailand
- 5National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency, Pathum Thani, Thailand
| | - Supachai Nitipan
- 6Department of Biology, Faculty of Sciences, Thaksin University, Phatthalung Campus, Phatthalung, Thailand
| | - Worawidh Wajjwalku
- 1Interdisciplinary Graduate Program in Genetic Engineering, Graduate School, Kasetsart University, Bangkok, Thailand
| | - Dietmar Haltrich
- 1Interdisciplinary Graduate Program in Genetic Engineering, Graduate School, Kasetsart University, Bangkok, Thailand
- 3Department of Food Sciences and Technology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Siriwan Prapong
- 1Interdisciplinary Graduate Program in Genetic Engineering, Graduate School, Kasetsart University, Bangkok, Thailand
- 2Department of Physiology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand
- 4Center for Advanced Studies for Agriculture and Food (CASAF), Institute for Advanced Studies, Kasetsart University, Bangkok, Thailand
| | - Suttipun Keawsompong
- 1Interdisciplinary Graduate Program in Genetic Engineering, Graduate School, Kasetsart University, Bangkok, Thailand
- 4Center for Advanced Studies for Agriculture and Food (CASAF), Institute for Advanced Studies, Kasetsart University, Bangkok, Thailand
- 7Department of Biotechnology, Faculty of Agro-Industry, Kasetsart University, Bangkok, Thailand
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Techawiwattanaboon T, Barnier-Quer C, Palaga T, Jacquet A, Collin N, Sangjun N, Komanee P, Piboonpocanun S, Patarakul K. Reduced Renal Colonization and Enhanced Protection by Leptospiral Factor H Binding Proteins as a Multisubunit Vaccine Against Leptospirosis in Hamsters. Vaccines (Basel) 2019; 7:vaccines7030095. [PMID: 31443566 PMCID: PMC6789851 DOI: 10.3390/vaccines7030095] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 08/19/2019] [Accepted: 08/20/2019] [Indexed: 12/17/2022] Open
Abstract
Subunit vaccines conferring complete protection against leptospirosis are not currently available. The interactions of factor H binding proteins (FHBPs) on pathogenic leptospires and host factor H are crucial for immune evasion by inhibition of complement-mediated killing. The inhibition of these interactions may be a potential strategy to clear leptospires in the host. This study aimed to evaluate a multisubunit vaccine composed of four known leptospiral FHBPs: LigA domain 7–13 (LigAc), LenA, LcpA, and Lsa23, for its protective efficacy in hamsters. The mono and multisubunit vaccines formulated with LMQ adjuvant, a combination of neutral liposome, monophosphoryl lipid A, and Quillaja saponaria fraction 21, induced high and comparable specific antibody (IgG) production against individual antigens. Hamsters immunized with the multisubunit vaccine showed 60% survival following the challenge by 20× LD50 of Leptospira interrogans serovar Pomona. No significant difference in survival rate and pathological findings of target organs was observed after vaccinations with multisubunit or mono-LigAc vaccines. However, the multisubunit vaccine significantly reduced leptospiral burden in surviving hamsters in comparison with the monosubunit vaccines. Therefore, the multisubunit vaccine conferred partial protection and reduced renal colonization against virulence Leptospira infection in hamsters. Our multisubunit formulation could represent a promising vaccine against leptospirosis.
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Affiliation(s)
- Teerasit Techawiwattanaboon
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand
| | | | - Tanapat Palaga
- Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Alain Jacquet
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand
| | - Nicolas Collin
- Vaccine Formulation Laboratory (VFL), University of Lausanne, 1066 Epalinges, Switzerland
| | - Noppadon Sangjun
- Armed Force Research Institute of Medical Sciences (AFRIMS), Ratchathewi, Bangkok 10400, Thailand
| | - Pat Komanee
- Armed Force Research Institute of Medical Sciences (AFRIMS), Ratchathewi, Bangkok 10400, Thailand
| | - Surapon Piboonpocanun
- Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Kanitha Patarakul
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand.
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand.
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14
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Teixeira AF, Fernandes LG, Cavenague MF, Takahashi MB, Santos JC, Passalia FJ, Daroz BB, Kochi LT, Vieira ML, Nascimento AL. Adjuvanted leptospiral vaccines: Challenges and future development of new leptospirosis vaccines. Vaccine 2019; 37:3961-3973. [DOI: 10.1016/j.vaccine.2019.05.087] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/16/2019] [Accepted: 05/21/2019] [Indexed: 12/26/2022]
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15
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da Cunha CEP, Bettin EB, Bakry AFAAY, Seixas Neto ACP, Amaral MG, Dellagostin OA. Evaluation of different strategies to promote a protective immune response against leptospirosis using a recombinant LigA and LigB chimera. Vaccine 2019; 37:1844-1852. [PMID: 30826147 DOI: 10.1016/j.vaccine.2019.02.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 01/30/2019] [Accepted: 02/03/2019] [Indexed: 11/17/2022]
Abstract
Leptospirosis is a zoonosis of worldwide distribution, caused by infection with pathogenic Leptospira species. The vaccines that are currently available are bacterins, with limited human use, that confer short-term, serovar-specific immunity. Lig proteins are considered to be the best vaccine candidates to date. Here, we aimed to construct a recombinant Lig chimera (LC) comprised of LigAni and LigBrep fragments, and to evaluate it as subunit or DNA vaccine using different administration strategies. Vaccines were formulated with 50 µg of recombinant LC associated with different adjuvants or with 100 µg of pTARGET/LC. Four-week-old hamsters received two doses of vaccine with different strategies and were challenged with 5 × DL50Leptospira interrogans serovar Copenhageni strain Fiocruz L1-130. The immune response generated by Lig chimera conferred 100% protection to hamsters treated with at least one dose of recombinant LC. Despite the high levels of antibodies that vaccinated animals produced, a sterilizing immunity was not achieved. The lack of a sterilizing immunity could indicate the importance of a mixed humoral and cellular immune response. The present study generated insights that will be useful in the future development of improved subunit vaccines against leptospirosis.
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Affiliation(s)
| | | | | | | | - Marta Gonçalves Amaral
- Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas, Brazil
| | - Odir Antonio Dellagostin
- Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas, Brazil.
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Evaluation of Lsa46 and Lsa77 Leptospiral Proteins for Their Immunoprotective Activities in Hamster Model of Leptospirosis. BIOMED RESEARCH INTERNATIONAL 2018; 2018:1813745. [PMID: 29984227 PMCID: PMC6015724 DOI: 10.1155/2018/1813745] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 05/13/2018] [Indexed: 11/18/2022]
Abstract
Leptospirosis is a neglected tropical disease caused by pathogenic Leptospira spp. The lack of an effective vaccine favors the increase of the disease. Currently, surface-exposed proteins are the main targets for the search of vaccine candidates. In this study, we examined whether the surface Lsa46 and Lsa77 proteins, previously identified as laminin and plasminogen binding proteins, have the capacity of inducing protection and sterilizing immunity against challenge with virulent Leptospira in hamster model. Animals were subcutaneously immunized with Lsa46, Lsa77, or a combination of both in Alum adjuvant and challenged intraperitoneally with L. interrogans serovar Kennewicki strain Pomona Fromm. Hamster immunization with Lsa46 or Lsa77 or both promoted a strong IgG response. Th2- and Th1-biased immune responses were observed when Lsa46 and Lsa77 were individually administered, respectively, as detected by the IgG1/IgG2/3 ratio. Immunized hamsters with the combined proteins induced a Th1-biased immune response. Although the immunization with Lsa46 and Lsa77 stimulated protective immunity with reduction of bacterial burden, when compared to animals individually immunized with the proteins, the data was not statistically significant. Thus, although promising, more studies are needed before the role of these proteins in stimulating sterilizing immunity in mammals is conclusively determined.
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17
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Pissawong T, Maneewatchararangsri S, Ritthisunthorn N, Soonthornworasiri N, Reamtong O, Adisakwattana P, Kalambaheti T, Chaisri U, Doungchawee G. Immunodominance of LipL32 93-272 peptides revealed by leptospirosis sera and therapeutic monoclonal antibodies. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2018; 53:11-22. [PMID: 29500044 DOI: 10.1016/j.jmii.2017.12.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 10/30/2017] [Accepted: 12/12/2017] [Indexed: 12/01/2022]
Abstract
BACKGROUND/PURPOSE Leptospirosis is a neglected zoonosis, imposing significant human and veterinary public health burdens. In this study, recombinant LipL3293-147 and LipL32148-184 middle domain of LipL3293-184, and LipL32171-214, and LipL32215-272 of c-terminal LipL32171-272 truncations were defined for immunodominance of the molecule during Leptospira infections revealed by leptospirosis sera. RESULTS IgM-dominant was directed to highly surface accessible LipL32148-184 and Lipl32171-214. IgG dominance of LipL32148-184 revealed by rabbit anti-Leptospira sera and convalescent leptospirosis paired sera were mapped to highly accessible surface of middle LipL32148-184 truncation whereas two LipL32148-184 and LipL32215-272 truncations were IgG-dominant when revealed by single leptospirosis sera. The IgM-dominant of LipL32148-214 and IgG-dominant LipL32148-184 peptides have highly conserved amino acids of 70% identity among pathogenic and intermediate Leptospira species and were mapped to the highly surface accessible area of LipL32 molecule that mediated interaction of host components. IgG dominance of two therapeutic epitopes located at LipL32243-253 and LipL32122-130 of mAbLPF1 and mAbLPF2, respectively has been shown less IgG-dominant (<30%), located outside IgG-dominant regions characterized by leptospirosis paired sera. CONCLUSION The IgM- and IgG-dominant LipL32 could be further perspectives for immunodominant LipL32-based serodiagnosis and LipL32 epitope-based vaccine.
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Affiliation(s)
- Tippawan Pissawong
- Chulabhorn International College of Medicine, Thammasat University, Pathumthani 12120, Thailand
| | - Santi Maneewatchararangsri
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand.
| | - Nonglucksanawan Ritthisunthorn
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Ngamphol Soonthornworasiri
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Onrapak Reamtong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Poom Adisakwattana
- Department of Helminthology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Thareerat Kalambaheti
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Urai Chaisri
- Department of Tropical Pathology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Galayanee Doungchawee
- Department of Pathobiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
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18
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Sritrakul T, Nitipan S, Wajjwalku W, La-Ard A, Suphatpahirapol C, Petkarnjanapong W, Ongphiphadhanakul B, Prapong S. Leptospira borgpetersenii hybrid leucine-rich repeat protein: Cloning and expression, immunogenic identification and molecular docking evaluation. J Microbiol Methods 2017; 142:52-62. [PMID: 28912108 DOI: 10.1016/j.mimet.2017.09.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 08/30/2017] [Accepted: 09/10/2017] [Indexed: 11/17/2022]
Abstract
Leptospirosis is an important zoonotic disease, and the major outbreak of this disease in Thailand in 1999 was due largely to the Leptospira borgpetersenii serovar Sejroe. Identification of the leucine-rich repeat (LRR) LBJ_2271 protein containing immunogenic epitopes and the discovery of the LBJ_2271 ortholog in Leptospira serovar Sejroe, KU_Sej_R21_2271, led to further studies of the antigenic immune properties of KU_Sej_LRR_2271. The recombinant hybrid (rh) protein was created and expressed from a hybrid PCR fragment of KU_Sej_R21_2271 fused with DNA encoding the LBJ_2271 signal sequence for targeting protein as a membrane-anchoring protein. The fusion DNA was cloned into pET160/GW/D-TOPO® to form the pET160_hKU_R21_2271 plasmid. The plasmid was used to express the rhKU_Sej_LRR_2271 protein in Escherichia coli BL21 Star™ (DE3). The expressed protein was immunologically detected by Western blotting and immunoreactivity detection with hyperimmune sera, T cell epitope prediction by HLA allele and epitope peptide binding affinity, and potential T cell reactivity analysis. The immunogenic epitopes of the protein were evaluated and verified by HLA allele and epitope peptide complex structure molecular docking. Among fourteen best allele epitopes of this protein, binding affinity values of 12 allele epitopes remained unchanged compared to LBJ_2271. Two epitopes for alleles HLA-A0202 and -A0301 had higher IC50 values, while T cell reactivity values of these peptides were better than values from LBJ_2271 epitopes. Eight of twelve epitope peptides had positive T-cell reactivity scores. Although the molecular docking of two epitopes, 3FPLLKEFLV11/47FPLLKEFLV55 and 50KLSTVPEGV58, into an HLA-A0202 model revealed a good fit in the docked structures, 50KLSTVPEGV58 and 94KLSTVPEEV102 are still considered as the proteins' best epitopes for allele HLA-A0202. The results of this study showed that rhKU_Sej_LRR_2271 protein contained natural immunological properties that should be further examined with respect to antigenic immune stimulation for vaccine development to prevent prevalent leptospiral serovar infection in Thailand.
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Affiliation(s)
- Tepyuda Sritrakul
- Department of Physiology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand; The Interdisciplinary Graduate Program in Genetic Engineering, the Graduate School, Kasetsart University, Bangkok 10900, Thailand
| | - Supachai Nitipan
- Department of Biology, Faculty of Science, Thaksin University, Phattalung campus, Phattalung Province, Thailand
| | - Worawidh Wajjwalku
- Faculty of Veterinary Medicine, Kamphaengsaen campus, Kasetsart University, NakornPathom Province, Thailand
| | - Anchalee La-Ard
- Faculty of Veterinary Medicine, Kamphaengsaen campus, Kasetsart University, NakornPathom Province, Thailand
| | - Chattip Suphatpahirapol
- Department of Physiology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand; The Interdisciplinary Graduate Program in Genetic Engineering, the Graduate School, Kasetsart University, Bangkok 10900, Thailand
| | - Wimol Petkarnjanapong
- The National Institute of Health of Thailand, Department of Medical Sciences, Ministry of Public Health, Nonthaburee Province, Thailand
| | - Boonsong Ongphiphadhanakul
- Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Siriwan Prapong
- Department of Physiology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand; The Interdisciplinary Graduate Program in Genetic Engineering, the Graduate School, Kasetsart University, Bangkok 10900, Thailand; Center for Advanced Studies for Agriculture and Food (CASAF), Kasetsart University, Bangkok, Thailand.
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19
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DNA vaccines against leptospirosis: A literature review. Vaccine 2017; 35:5559-5567. [PMID: 28882437 DOI: 10.1016/j.vaccine.2017.08.067] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 08/21/2017] [Accepted: 08/24/2017] [Indexed: 01/19/2023]
Abstract
Leptospirosis is an infectious disease caused by pathogenic Leptospira species. The vaccines that are currently available for leptospirosis are composed of whole-cell preparations and suffer from limitations such as low efficacy, multiple side-effects, poor immunological memory and lack of cross-protection against different serovars of Leptospira spp. In light of the global prevalence of this disease, the development of a more effective vaccine against leptospirosis is of paramount importance. Genetic immunization is a promising alternative to conventional vaccine development. In the last 25years, several novel strategies have been developed for increasing the efficacy of DNA vaccines. Examples of such strategies include the introduction of novel plasmid vectors, adjuvants, alternate delivery routes, and prime-boost regimens. Herein we discuss the latest and most promising advances that have been made in developing DNA vaccines against leptospirosis. We also deliberate over the future directions that must be undertaken in order to improve results in this field.
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20
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Fernandes LG, Teixeira AF, Filho AF, Souza GO, Vasconcellos SA, Heinemann MB, Romero EC, Nascimento AL. Immune response and protective profile elicited by a multi-epitope chimeric protein derived from Leptospira interrogans. Int J Infect Dis 2017; 57:61-69. [DOI: 10.1016/j.ijid.2017.01.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 01/04/2017] [Accepted: 01/25/2017] [Indexed: 10/20/2022] Open
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21
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Grassmann AA, Souza JD, McBride AJA. A Universal Vaccine against Leptospirosis: Are We Going in the Right Direction? Front Immunol 2017; 8:256. [PMID: 28337203 PMCID: PMC5343615 DOI: 10.3389/fimmu.2017.00256] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 02/21/2017] [Indexed: 12/22/2022] Open
Abstract
Leptospirosis is the most widespread zoonosis in the world and a neglected tropical disease estimated to cause severe infection in more than one million people worldwide every year that can be combated by effective immunization. However, no significant progress has been made on the leptospirosis vaccine since the advent of bacterins over 100 years. Although protective against lethal infection, particularly in animals, bacterin-induced immunity is considered short term, serovar restricted, and the vaccine can cause serious side effects. The urgent need for a new vaccine has motivated several research groups to evaluate the protective immune response induced by recombinant vaccines. Significant protection has been reported with several promising outer membrane proteins, including LipL32 and the leptospiral immunoglobulin-like proteins. However, efficacy was variable and failed to induce a cross-protective response or sterile immunity among vaccinated animals. As hundreds of draft genomes of all known Leptospira species are now available, this should aid novel target discovery through reverse vaccinology (RV) and pangenomic studies. The identification of surface-exposed vaccine candidates that are highly conserved among infectious Leptospira spp. is a requirement for the development of a cross-protective universal vaccine. However, the lack of immune correlates is a major drawback to the application of RV to Leptospira genomes. In addition, as the protective immune response against leptospirosis is not fully understood, the rational use of adjuvants tends to be a process of trial and error. In this perspective, we discuss current advances, the pitfalls, and possible solutions for the development of a universal leptospirosis vaccine.
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Affiliation(s)
- André Alex Grassmann
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas , Pelotas , Brazil
| | - Jéssica Dias Souza
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas , Pelotas , Brazil
| | - Alan John Alexander McBride
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Brazil; Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Ministry of Health, Salvador, Brazil
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22
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Dellagostin OA, Grassmann AA, Rizzi C, Schuch RA, Jorge S, Oliveira TL, McBride AJA, Hartwig DD. Reverse Vaccinology: An Approach for Identifying Leptospiral Vaccine Candidates. Int J Mol Sci 2017; 18:ijms18010158. [PMID: 28098813 PMCID: PMC5297791 DOI: 10.3390/ijms18010158] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 01/05/2017] [Accepted: 01/06/2017] [Indexed: 12/01/2022] Open
Abstract
Leptospirosis is a major public health problem with an incidence of over one million human cases each year. It is a globally distributed, zoonotic disease and is associated with significant economic losses in farm animals. Leptospirosis is caused by pathogenic Leptospira spp. that can infect a wide range of domestic and wild animals. Given the inability to control the cycle of transmission among animals and humans, there is an urgent demand for a new vaccine. Inactivated whole-cell vaccines (bacterins) are routinely used in livestock and domestic animals, however, protection is serovar-restricted and short-term only. To overcome these limitations, efforts have focused on the development of recombinant vaccines, with partial success. Reverse vaccinology (RV) has been successfully applied to many infectious diseases. A growing number of leptospiral genome sequences are now available in public databases, providing an opportunity to search for prospective vaccine antigens using RV. Several promising leptospiral antigens were identified using this approach, although only a few have been characterized and evaluated in animal models. In this review, we summarize the use of RV for leptospirosis and discuss the need for potential improvements for the successful development of a new vaccine towards reducing the burden of human and animal leptospirosis.
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Affiliation(s)
- Odir A Dellagostin
- Núcleo de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas RS 96100-000, Brazil.
| | - André A Grassmann
- Núcleo de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas RS 96100-000, Brazil.
| | - Caroline Rizzi
- Núcleo de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas RS 96100-000, Brazil.
| | - Rodrigo A Schuch
- Núcleo de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas RS 96100-000, Brazil.
| | - Sérgio Jorge
- Núcleo de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas RS 96100-000, Brazil.
| | - Thais L Oliveira
- Núcleo de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas RS 96100-000, Brazil.
| | - Alan J A McBride
- Núcleo de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas RS 96100-000, Brazil.
| | - Daiane D Hartwig
- Departamento de Microbiologia e Parasitologia, Instituto de Biologia, Universidade Federal de Pelotas, Pelotas RS 96100-000, Brazil.
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Abstract
Lipoproteins are lipid-modified proteins that dominate the spirochetal proteome. While found in all bacteria, spirochetal lipoproteins have unique features and play critical roles in spirochete biology. For this reason, considerable effort has been devoted to determining how the lipoproteome is generated. Essential features of the structural elements of lipoproteins are now understood with greater clarity, enabling greater confidence in identification of lipoproteins from genomic sequences. The journey from the ribosome to the outer membrane, and in some cases, to the cellular surface has been defined, including secretion, lipidation, sorting, and export across the outer membrane. Given their abundance and importance, it is not surprising that spirochetes have developed a number of strategies for regulating the spatiotemporal expression of lipoproteins. In some cases, lipoprotein expression is tied to various environmental cues, while in other cases, it is linked to growth rate. This regulation enables spirochetes to express certain lipoproteins at high levels in one phase of the spirochete lifecycle, while dramatically downregulating the same lipoproteins in other phases. The mammalian host has developed specialized mechanisms for recognizing lipoproteins and triggering an immune response. Evasion of that immune response is essential for spirochete persistence. For this reason, spirochetes have developed mechanisms for altering lipoproteins. Lipoproteins recognized by antibodies formed during infection are key serodiagnostic antigens. In addition, lipoprotein vaccines have been developed for generating an immune response to control or prevent a spirochete infection. This chapter summarizes our current understanding of lipoproteins in interactions of spirochetes with their hosts.
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24
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Oliveira TL, Grassmann AA, Schuch RA, Seixas Neto ACP, Mendonça M, Hartwig DD, McBride AJA, Dellagostin OA. Evaluation of the Leptospira interrogans Outer Membrane Protein OmpL37 as a Vaccine Candidate. PLoS One 2015; 10:e0142821. [PMID: 26588685 PMCID: PMC4654524 DOI: 10.1371/journal.pone.0142821] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 10/27/2015] [Indexed: 12/22/2022] Open
Abstract
The identification of potential vaccine candidates against leptospirosis remains a challenge. However, one such candidate is OmpL37, a potentially surface-exposed antigen that has the highest elastin-binding ability described to date, suggesting that it plays an important role in host colonization. In order to evaluate OmpL37's ability to induce a protective immune response, prime-boost, DNA and subunit vaccine strategies were tested in the hamster model of lethal leptospirosis. The humoral immune response was evaluated using an indirect ELISA test, and the cytokine profile in whole blood was determined by quantitative real-time PCR. Unlike the DNA vaccine, the administration of recombinant OmpL37 induced a strong IgG antibody response. When individually administrated, both formulations stimulated a TNF-α mediated inflammatory response. However, none of the OmpL37 formulations or vaccination strategies induced protective immunity. Further studies are required towards the identification of new vaccine targets against leptospirosis.
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Affiliation(s)
- Thaís Larré Oliveira
- Programa de Pós-Graduação em Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas, RS, Brazil
| | - André Alex Grassmann
- Programa de Pós-Graduação em Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas, RS, Brazil
| | - Rodrigo Andrade Schuch
- Programa de Pós-Graduação em Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas, RS, Brazil
| | - Amilton Clair Pinto Seixas Neto
- Programa de Pós-Graduação em Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas, RS, Brazil
| | - Marcelo Mendonça
- Programa de Pós-Graduação em Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas, RS, Brazil
| | - Daiane Drawanz Hartwig
- Programa de Pós-Graduação em Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas, RS, Brazil
- Departamento de Microbiologia e Parasitologia, Instituto de Biologia, Universidade Federal de Pelotas, Pelotas, RS, Brazil
| | - Alan John Alexander McBride
- Programa de Pós-Graduação em Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas, RS, Brazil
| | - Odir Antônio Dellagostin
- Programa de Pós-Graduação em Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas, RS, Brazil
- * E-mail:
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Protective Immunity and Reduced Renal Colonization Induced by Vaccines Containing Recombinant Leptospira interrogans Outer Membrane Proteins and Flagellin Adjuvant. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2015; 22:965-73. [PMID: 26108285 DOI: 10.1128/cvi.00285-15] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 06/17/2015] [Indexed: 11/20/2022]
Abstract
Leptospirosis is a global zoonotic disease caused by different Leptospira species, such as Leptospira interrogans, that colonize the renal tubules of wild and domestic animals. Thus far, attempts to develop effective leptospirosis vaccines, both for humans and animals, have failed to induce immune responses capable of conferring protection and simultaneously preventing renal colonization. In this study, we evaluated the protective immunity induced by subunit vaccines containing seven different recombinant Leptospira interrogans outer membrane proteins, including the carboxy-terminal portion of the immunoglobulinlike protein A (LigA(C)) and six novel antigens, combined with aluminum hydroxide (alum) or Salmonella flagellin (FliC) as adjuvants. Hamsters vaccinated with the different formulations elicited high antigen-specific antibody titers. Immunization with LigA(C), either with alum or flagellin, conferred protective immunity but did not prevent renal colonization. Similarly, animals immunized with LigA(C) or LigA(C) coadministered with six leptospiral proteins with alum adjuvant conferred protection but did not reduce renal colonization. In contrast, immunizing animals with the pool of seven antigens in combination with flagellin conferred protection and significantly reduced renal colonization by the pathogen. The present study emphasizes the relevance of antigen composition and added adjuvant in the efficacy of antileptospirosis subunit vaccines and shows the complex relationship between immune responses and renal colonization by the pathogen.
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Immunological and molecular characterization of Leptospira interrogans isolated from a bovine foetus. Comp Immunol Microbiol Infect Dis 2015; 40:41-5. [DOI: 10.1016/j.cimid.2015.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 03/30/2015] [Accepted: 04/07/2015] [Indexed: 11/17/2022]
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Evaluation of cell binding activities of Leptospira ECM adhesins. PLoS Negl Trop Dis 2015; 9:e0003712. [PMID: 25875373 PMCID: PMC4397020 DOI: 10.1371/journal.pntd.0003712] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 03/19/2015] [Indexed: 12/02/2022] Open
Abstract
Pathogenic spirochetes of the genus Leptospira are the causative agents of leptospirosis, a zoonotic infection that occurs globally. The bacteria colonize the renal proximal tubules of many animals and are shed in the urine. Contact with the urine, or with water contaminated with the urine of infected animals can cause infection of new host animals, including humans. Mechanisms of colonization of the proximal tubule and other tissues are not known, but specific interactions between bacterial adhesins and host substrates are likely to be critical in this process. Several extracellular matrix (ECM) adhesins have been previously identified, but more recently, it has been shown that Leptospira bind more efficiently to cells than ECM. In this work, recombinant forms of five putative Leptospira ECM adhesins, namely LipL32, Loa22, OmpL1, p31/LipL45, and LenA were evaluated for binding to cells as well as an expanded variety of ECM components. Reproducible and significant adhesin activity was demonstrated only for OmpL1, which bound to both mammalian cell lines tested and to glycosaminoglycans (GAGs). While determination of biologically significant bacterial adhesion activity will require generation of site-directed mutant strains, our results suggest that OmpL1 is a strong candidate for future evaluation regarding the roles of the adhesin activity of the protein during L. interrogans infection. Leptospirosis is the most widespread zoonotic infection in the world and represents a major public health problem, especially in tropical climates. The processes by which some Leptospira species cause infection, disease, and colonization of carrier animals remains poorly understood. Specific binding of Leptospira molecules and host molecules are likely important for infection and colonization. To identify Leptospira molecules that mediate attachment to host substrates, prior studies have evaluated Leptospira membrane proteins for binding to extracellular matrix (ECM) proteins. More recent data, however, show that Leptospira bind more efficiently to cells than to ECM. In search of adhesins mediating the latter activity, our study evaluated the direct cell binding activity of recombinant forms of a group of previously reported Leptospira ECM adhesins. Only one of these proteins, OmpL1, demonstrated reproducible direct cell binding activity. Further work will focus on identification of the mammalian receptor for OmpL1 and determining the biological significance of this activity during infection.
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Kumar V, Damodharan S, Pandaranayaka EP, Madathiparambil MG, Tennyson J. Molecular modeling andin-silicoengineering ofCardamom mosaic viruscoat protein for the presentation of immunogenic epitopes ofLeptospiraLipL32. J Biomol Struct Dyn 2015; 34:42-56. [DOI: 10.1080/07391102.2015.1009491] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Abstract
Vaccines against leptospirosis followed within a year of the first isolation of Leptospira, with the first use of a killed whole cell bacterin vaccine in guinea pigs published in 1916. Since then, bacterin vaccines have been used in humans, cattle, swine, and dogs and remain the only vaccines licensed at the present time. The immunity elicited is restricted to serovars with related lipopolysaccharide (LPS) antigen. Likewise, vaccines based on LPS antigens have clearly demonstrated protection in animal models, which is also at best serogroup specific. The advent of leptospiral genome sequences has allowed a reverse vaccinology approach for vaccine development. However, the use of inadequate challenge doses and inappropriate statistical analysis invalidates many of the claims of protection with recombinant proteins.
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Affiliation(s)
- Ben Adler
- Department of Microbiology, Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, VIC, 3800, Australia,
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Abstract
The outer membrane (OM) is the front line of leptospiral interactions with their environment and the mammalian host. Unlike most invasive spirochetes, pathogenic leptospires must be able to survive in both free-living and host-adapted states. As organisms move from one set of environmental conditions to another, the OM must cope with a series of conflicting challenges. For example, the OM must be porous enough to allow nutrient uptake, yet robust enough to defend the cell against noxious substances. In the host, the OM presents a surface decorated with adhesins and receptors for attaching to, and acquiring, desirable host molecules such as the complement regulator, Factor H.Factor H. On the other hand, the OM must enable leptospires to evade detection by the host's immune system on their way from sites of invasion through the bloodstream to the protected niche of the proximal tubule. The picture that is emerging of the leptospiral OM is that, while it shares many of the characteristics of the OMs of spirochetes and Gram-negative bacteria, it is also unique and different in ways that make it of general interest to microbiologists. For example, unlike most other pathogenic spirochetes, the leptospiral OM is rich in lipopolysaccharide (LPS). Leptospiral LPS is similar to that of Gram-negative bacteria but has a number of unique structural features that may explain why it is not recognized by the LPS-specific Toll-like receptor 4 of humans. As in other spirochetes, lipoproteins are major components of the leptospiral OM, though their roles are poorly understood. The functions of transmembrane outer membrane proteins (OMPs) in many cases are better understood, thanks to homologies with their Gram-negative counterparts and the emergence of improved genetic techniques. This chapter will review recent discoveries involving the leptospiral OM and its role in leptospiral physiology and pathogenesis.
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Affiliation(s)
- David A Haake
- Division of Infectious Diseases, VA Greater Los Angeles Healthcare System, Los Angeles, CA, 90073, USA,
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Abstract
Pathogenic Leptospira has the capacity to infect a broad range of mammalian hosts. Leptospirosis may appear as an acute, potentially fatal infection in accidental hosts, or progress into a chronic, largely asymptomatic infection in natural maintenance hosts. The course that Leptospira infection follows is dependent upon poorly understood factors, but is heavily influenced by both the host species and bacterial serovar involved in infection. Recognition of pathogen-associated molecular patterns (PAMPs) by a variety of host pattern recognition receptors (PRRs) activates the host immune system. The outcome of this response may result in bacterial clearance, limited bacterial colonization of a few target organs, principally the kidney, or induction of sepsis as the host succumbs to infection and dies. This chapter describes current knowledge of how the host recognizes Leptospira and responds to infection using innate and acquired immune responses. Aspects of immune-mediated pathology and pathogen strategies to evade the host immune response are also addressed.
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Affiliation(s)
- Richard L Zuerner
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University for Agricultural Sciences, 75007, Uppsala, Sweden,
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Xanthan gum as an adjuvant in a subunit vaccine preparation against leptospirosis. BIOMED RESEARCH INTERNATIONAL 2014; 2014:636491. [PMID: 24895594 PMCID: PMC4033433 DOI: 10.1155/2014/636491] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 04/11/2014] [Accepted: 04/11/2014] [Indexed: 02/02/2023]
Abstract
Leptospiral immunoglobulin-like (Lig) proteins are of great interest due to their ability to act as mediators of pathogenesis, serodiagnostic antigens, and immunogens. Purified recombinant LigA protein is the most promising subunit vaccine candidate against leptospirosis reported to date, however, as purified proteins are weak immunogens the use of a potent adjuvant is essential for the success of LigA as a subunit vaccine. In the present study, we compared xanthan pv. pruni (strain 106), aluminium hydroxide (alhydrogel), and CpG ODN as adjuvants in a LigA subunit vaccine preparation. Xanthan gum is a high molecular weight extracellular polysaccharide produced by fermentation of Xanthomonas spp., a plant-pathogenic bacterium genus. Preparations containing xanthan induced a strong antibody response comparable to that observed when alhydrogel was used. Upon challenge with a virulent strain of L. interrogans serovar Copenhageni, significant protection (Fisher test, P < 0.05) was observed in 100%, 100%, and 67% of hamsters immunized with rLigANI-xanthan, LigA-CpG-xanthan, and rLigANI-alhydrogel, respectively. Furthermore, xanthan did not cause cytotoxicity in Chinese hamster ovary (CHO) cells in vitro. The use of xanthan as an adjuvant is a novel alternative for enhancing the immunogenicity of vaccines against leptospirosis and possibly against other pathogens.
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Deveson Lucas DS, Lo M, Bulach DM, Quinsey NS, Murray GL, Allen A, Adler B. Recombinant LipL32 stimulates interferon-gamma production in cattle vaccinated with a monovalent Leptospira borgpetersenii serovar Hardjo subtype Hardjobovis vaccine. Vet Microbiol 2014; 169:163-70. [DOI: 10.1016/j.vetmic.2013.12.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2013] [Revised: 12/19/2013] [Accepted: 12/20/2013] [Indexed: 12/01/2022]
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Vaccination with leptospiral outer membrane lipoprotein LipL32 reduces kidney invasion of Leptospira interrogans serovar canicola in hamsters. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2014; 21:546-51. [PMID: 24521782 DOI: 10.1128/cvi.00719-13] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Leptospira interrogans vaccines currently available are serovar specific and require regular booster immunizations to maintain protection of the host. In addition, a hamster challenge batch potency test is necessary to evaluate these vaccines prior to market release, requiring the use of a large number of animals, which is ethically and financially undesirable. Our previous work showed that the N terminus of the outer membrane protein LipL32 was altered in Leptospira interrogans serovar Canicola vaccines that fail the hamster challenge test, suggesting that it may be involved in the protective immune response. The aim of this study was to determine if vaccination with LipL32 protein alone could provide a protective response against challenge with L. interrogans serovar Canicola to hamsters. Recombinant LipL32, purified from an Escherichia coli expression system, was assessed for protective immunity in five groups of hamsters (n = 5) following a challenge with the virulent L. interrogans serovar Canicola strain Kito as a challenge strain. However, no significant survival against the L. interrogans serovar Canicola challenge was observed compared to that of unvaccinated negative controls. Subsequent histological analysis revealed reduced amounts of L. interrogans in the kidneys from the hamsters vaccinated with recombinant LipL32 protein prior to challenge; however, no significant survival against the L. interrogans serovar Canicola challenge was observed compared to that of unvaccinated negative controls. This finding corresponded to a noticeably reduced severity of renal lesions. This study provides evidence that LipL32 is involved in the protective response against L. interrogans serovar Canicola in hamsters and is the first reported link to LipL32-induced protection against kidney invasion.
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Hartwig DD, Bacelo KL, Oliveira PDD, Oliveira TL, Seixas FK, Amaral MG, Hartleben CP, McBride AJA, Dellagostin OA. Mannosylated LigANI produced in Pichia pastoris protects hamsters against leptospirosis. Curr Microbiol 2013; 68:524-30. [PMID: 24343176 DOI: 10.1007/s00284-013-0505-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 10/27/2013] [Indexed: 01/12/2023]
Abstract
The C-terminal region of the Leptospiral immunoglobulin-like A protein (LigA) contains six carboxy-terminal Ig-like repeat domains (LigANI). Subunit vaccine preparations based on recombinant LigANI produced in Escherichia coli, are promising vaccine candidates, albeit with variable efficacy. In the present study, LigANI was expressed in the methylotrophic yeast Pichia pastoris using a 12 L bioreactor to produce mannosylated LigANI (mLigANI) for use in a vaccine preparation against leptospirosis. Hamsters immunized with a mLigANI vaccine preparation produced a significant IgG antibody response (P < 0.001) and were protected (83.3 %; P < 0.001) against lethal challenge with 36× LD50 of a virulent strain of L. interrogans serovar Copenhageni. A vaccine preparation based on demannosylated mLigANI (nmLigANI) elicited an immune response in hamsters, but did not afford protection. The production of mLigANI in bioreactor by P. pastoris yielded ~50 mg L(-1) of recombinant protein. P. pastoris is a potential platform for the production of leptospiral antigens on an industrial scale. The results demonstrate that LigANI secreted by P. pastoris on mannosylated form (mLigANI) protect hamsters as subunit vaccine of L. interrogans lethal infection.
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Affiliation(s)
- Daiane D Hartwig
- Unidade de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas, RS, Brazil,
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Raja V, Natarajaseenivasan K. Pathogenic, diagnostic and vaccine potential of leptospiral outer membrane proteins (OMPs). Crit Rev Microbiol 2013; 41:1-17. [PMID: 23688248 DOI: 10.3109/1040841x.2013.787387] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Pathogenic Leptospira species are important human and animal pathogen that causes leptospirosis, with more than half a million cases reported annually but little is known regarding the true incidence of leptospirosis due to the limitations in diagnosis. Proteins embedded in the outer membrane are found to be prime drug targets due to its key role as receptors for cellular communication and gatekeepers for iron and substrate transport across cell membranes. The major key issues to be addressed to overcome the disease burden of leptospirosis are: need to identify the genes that turn on in vivo; development of rapid diagnostic methods to facilitate the early diagnosis and to develop a universal vaccine. Recent whole genome sequencing of Leptospira species and development of in silico analysis tools have led to the identification of a large number of leptospiral virulence genes, metabolic pathways and surface protein secretion systems that represent potential new targets for the development of anti-leptospiral drug, vaccine and diagnostic strategies. This review surveys the different types of outer membrane proteins (OMPs) of Leptospira and combines all the novel features of OMPs reported till date and put forth some views for future research.
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Affiliation(s)
- Veerapandian Raja
- Medical Microbiology Laboratory, Department of Microbiology, Bharathidasan University , Tiruchirappalli , India
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Pinne M, Haake DA. LipL32 Is a Subsurface Lipoprotein of Leptospira interrogans: presentation of new data and reevaluation of previous studies. PLoS One 2013; 8:e51025. [PMID: 23323152 PMCID: PMC3544172 DOI: 10.1371/journal.pone.0051025] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2012] [Accepted: 10/29/2012] [Indexed: 11/19/2022] Open
Abstract
The agents of leptospirosis, a zoonosis with worldwide distribution, are pathogenic spirochetes belonging to the genus Leptospira. The leptospiral life cycle involves transmission via fresh water and colonization of the renal tubules of their reservoir hosts. Infection of accidental hosts, including humans, may result in life-threatening sequelae. Bacterial outer membrane proteins (OMPs), particularly those with surface-exposed regions, play crucial roles in pathogen virulence mechanisms and adaptation to environmental conditions, including those found in the mammalian host. Therefore, elucidation and characterization of the surface-exposed OMPs of Leptospira spp. is of great interest in the leptospirosis field. A thorough, multi-pronged approach for assessing surface exposure of leptospiral OMPs is essential. Herein, we present evidence for a sub-surface location for most or all of the major leptospiral lipoprotein, LipL32, based on surface immunofluorescence utilizing three different types of antibodies and four different permeabilization methods, as well as surface proteolysis of intact and lysed leptospires. We reevaluate prior evidence presented in support of LipL32 surface-exposure and present a novel perspective on a protein whose location has been misleading researchers, due in large part to its extraordinary abundance in leptospiral cells.
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Affiliation(s)
- Marija Pinne
- Research Service, Veterans Affairs Greater Los Angeles Healthcare System, Los
Angeles, California, United States of America
- Department of Medicine, David Geffen School of Medicine, University of California
Los Angeles, Los Angeles, California, United States of America
- * E-mail:
| | - David A. Haake
- Division of Infectious Diseases, Veterans Affairs Greater Los Angeles Healthcare
System, Los Angeles, California, United States of America
- Department of Medicine, David Geffen School of Medicine, University of California
Los Angeles, Los Angeles, California, United States of America
- Department of Urology, David Geffen School of Medicine, University of California
Los Angeles, Los Angeles, California, United States of America
- Department of Microbiology, Immunology & Molecular Genetics, University of
California Los Angeles, Los Angeles, California, United States of America
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Kucerova P, Cermakova Z, Pliskova L, Pavlis O, Kubickova P, Kleprlikova H, Valenta Z. Our experience using real-time PCR for the detection of the gene that encodes the superficial lipoprotein LipL32 of the pathogenic leptospires to confirm the acute form of human leptospirosis. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2012; 157:387-91. [PMID: 23235722 DOI: 10.5507/bp.2012.109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 12/03/2012] [Indexed: 11/23/2022] Open
Abstract
AIMS To examine biological materials (blood, urine, cerebrospinal fluid) of patients with suspected leptospirosis using real-time PCR for detecting the gene that codes the superficial LipL32 lipoprotein, and to evaluate the contribution of the real-time PCR method for the laboratory diagnosis of the acute form of leptospirosis. MATERIAL AND METHODS During the monitored period of April 2010 - December 2011, a total of 340 biological materials samples were examined (177x blood plasma, 88x urine, 68x, cerebrospinal fluid, 6x bronchoalveolar lavage and 1x sputum) from 216 patients with suspected leptospirosis using real-time PCR LipL32 gene detection. RESULTS From the mentioned 216 patients suspected of leptospirosis, 8 patients were evaluated as being PCR LipL32 positive, from which 14 positive biological materials originated (9 x urine, 4x blood and 1x liquor). CONCLUSION As demonstrated in the study, the real-time PCR method for detecting the gene for the superficial lipoprotein LipL32 is an appropriate, quick and reliable method for the diagnosis of the acute form of leptospirosis.
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Affiliation(s)
- Petra Kucerova
- Department of Clinical Microbiology, Faculty of Medicine in Hradec Kralove, Charles University in Prague and University Hospital in Hradec Kralove, Hradec Kralove, Czech Republic
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Murray GL, Lo M, Bulach DM, Srikram A, Seemann T, Quinsey NS, Sermswan RW, Allen A, Adler B. Evaluation of 238 antigens of Leptospira borgpetersenii serovar Hardjo for protection against kidney colonisation. Vaccine 2012. [PMID: 23176980 DOI: 10.1016/j.vaccine.2012.11.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Leptospirosis is a zoonotic disease affecting animals and humans worldwide. Leptospiral infection in cattle can cause reproductive failure and reduced weight gain, and importantly, infection represents a significant disease risk for farmers. Current bacterin vaccines offer protection that is short-lived and restricted at best to related serovars. The development of protective vaccines that stimulate immunity across multiple leptospiral serovars would therefore be advantageous. This study used a reverse vaccinology approach to evaluate a set of Leptospira borgpetersenii proteins in the hamster infection model. The L. borgpetersenii serovar Hardjo strain L550 genome sequence was analysed and genes encoding 262 predicted outer membrane or secreted proteins were selected. From this list, 238 proteins or protein fragments were successfully expressed and purified; 28 proteins (12%) were soluble, while the remaining 210 proteins (88%) were insoluble and purified under denaturing conditions. Proteins were mixed into 48 pools of up to five each and tested for protection against infection as assessed by renal colonisation in the hamster model of infection. None of the pools of antigens protected the hamsters against infection, despite a detectable antibody response being mounted against the majority of proteins (71%). This study is the first large scale evaluation of individual leptospiral proteins for ability to induce a protective immune response in the hamster infection model. It thus constitutes an important reference of protein immunogenicity and non-protective antigens that should be consulted before embarking on any future subunit vaccine experiments.
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Affiliation(s)
- Gerald L Murray
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Departments of Microbiology and Biochemistry & Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
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OmpL1 is an extracellular matrix- and plasminogen-interacting protein of Leptospira spp. Infect Immun 2012; 80:3679-92. [PMID: 22802342 DOI: 10.1128/iai.00474-12] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Leptospirosis is a zoonosis with multisystem involvement caused by pathogenic strains of the genus Leptospira. OmpL1 is an outer membrane protein of Leptospira spp. that is expressed during infection. In this work, we investigated novel features of this protein. We describe that OmpL1 is a novel leptospiral extracellular matrix (ECM)-binding protein and a plasminogen (PLG) receptor. The recombinant protein was expressed in Escherichia coli BL21(DE3) Star/pLysS as inclusion bodies, refolded, and purified by metal-chelating chromatography. The protein presented a typical β-strand secondary structure, as evaluated by circular dichroism spectroscopy. The recombinant protein reacted with antibodies in serum samples from convalescent leptospirosis patients with a high specificity compared to serum samples from individuals with unrelated diseases. These data strengthen the usefulness of OmpL1 as a diagnostic marker of leptospirosis. The characterization of the immunogenicity of recombinant OmpL1 in inoculated BALB/c mice showed that the protein has the capacity to elicit humoral and cellular immune responses, as denoted by high antibody titers and the proliferation of lymphocytes. We demonstrate that OmpL1 has the ability to mediate attachment to laminin and plasma fibronectin, with K(D) (equilibrium dissociation constant) values of 2,099.93 ± 871.03 nM and 1,239.23 ± 506.85 nM, respectively. OmpL1 is also a PLG receptor, with a K(D) of 368.63 ± 121.23 nM, capable of generating enzymatically active plasmin. This is the first report that shows and characterizes OmpL1 as an ECM-interacting and a PLG-binding protein of Leptospira spp. that may play a role in bacterial pathogenesis when expressed during infection.
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Protection against lethal leptospirosis after vaccination with LipL32 coupled or coadministered with the B subunit of Escherichia coli heat-labile enterotoxin. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2012; 19:740-5. [PMID: 22379066 DOI: 10.1128/cvi.05720-11] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Leptospirosis, a worldwide zoonosis, lacks an effective, safe, and cross-protective vaccine. LipL32, the most abundant, immunogenic, and conserved surface lipoprotein present in all pathogenic species of Leptospira, is a promising antigen candidate for a recombinant vaccine. However, several studies have reported a lack of protection when this protein is used as a subunit vaccine. In an attempt to enhance the immune response, we used LipL32 coupled to or coadministered with the B subunit of the Escherichia coli heat-labile enterotoxin (LTB) in a hamster model of leptospirosis. After homologous challenge with 5× the 50% lethal dose (LD(50)) of Leptospira interrogans, animals vaccinated with LipL32 coadministered with LTB and LTB::LipL32 had significantly higher survival rates (P < 0.05) than animals from the control group. This is the first report of a protective immune response afforded by a subunit vaccine using LipL32 and represents an important contribution toward the development of improved leptospirosis vaccines.
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Analysis of multiple Leptospira interrogans serovar Canicola vaccine proteomes and identification of LipL32 as a biomarker for potency. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2012; 19:587-93. [PMID: 22323560 DOI: 10.1128/cvi.05622-11] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The current batch potency test for Leptospira interrogans serovar Canicola vaccines requires the use of a large number of hamsters and has severe effects (i.e., hepatic and renal failure resulting in death); while this vaccine is effective, a safer, cheaper, more ethical replacement is desired. The aim of this study was to analyze vaccine proteomes and identify target molecules common to all L. interrogans serovar Canicola vaccines which could be used to design an in vitro potency test. Initial analysis of L. interrogans serovar Canicola vaccines (A to E) from different manufacturers, using the Limulus amebocyte lysate assay and silver-stained sodium dodecyl sulfate polyacrylamide gels, indicated that lipopolysaccharide was not present in all vaccines, preventing it from being a suitable target molecule. The protein contents of vaccines A to E were therefore determined by two-dimensional liquid chromatography mass spectrometry ([2D-LC/MS] 221 ± 31, 9 ± 8, 34 ± 4, 21 ± 5, and 34 ± 17 proteins [mean ± 1 standard deviation] found, respectively). The outer membrane protein LipL32 was established to be common to all and to be present at a significantly higher (P ≤ 0.05) relative spectral abundance in a batch of vaccine which passed the in vivo potency test than in one which had failed. Further analysis using multiple reaction monitoring revealed that the concentration of the N terminus of LipL32 was significantly lower (P ≤ 0.01) in failed batches (n = 2) of vaccine than in passed batches (n = 2); the concentration of the C terminus between the two batches was approximately the same. An in vitro Leptospira vaccine potency test, based on N-terminal amino acid quantification of LipL32, was subsequently developed.
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Coutinho ML, Choy HA, Kelley MM, Matsunaga J, Babbitt JT, Lewis MS, Aleixo JAG, Haake DA. A LigA three-domain region protects hamsters from lethal infection by Leptospira interrogans. PLoS Negl Trop Dis 2011; 5:e1422. [PMID: 22180800 PMCID: PMC3236721 DOI: 10.1371/journal.pntd.0001422] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 10/23/2011] [Indexed: 11/19/2022] Open
Abstract
The leptospiral LigA protein consists of 13 bacterial immunoglobulin-like (Big) domains and is the only purified recombinant subunit vaccine that has been demonstrated to protect against lethal challenge by a clinical isolate of Leptospira interrogans in the hamster model of leptospirosis. We determined the minimum number and location of LigA domains required for immunoprotection. Immunization with domains 11 and 12 was found to be required but insufficient for protection. Inclusion of a third domain, either 10 or 13, was required for 100% survival after intraperitoneal challenge with Leptospira interrogans serovar Copenhageni strain Fiocruz L1-130. As in previous studies, survivors had renal colonization; here, we quantitated the leptospiral burden by qPCR to be 1.2×10(3) to 8×10(5) copies of leptospiral DNA per microgram of kidney DNA. Although renal histopathology in survivors revealed tubulointerstitial changes indicating an inflammatory response to the infection, blood chemistry analysis indicated that renal function was normal. These studies define the Big domains of LigA that account for its vaccine efficacy and highlight the need for additional strategies to achieve sterilizing immunity to protect the mammalian host from leptospiral infection and its consequences.
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Affiliation(s)
- Mariana L. Coutinho
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, United States of America
- Centro de Desenvolvimento Tecnologico, Universidade Federal de Pelotas, Pelotas, Brasil
| | - Henry A. Choy
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, United States of America
- Department of Medicine, David Geffen School of Medicine at University of California Los Angeles (UCLA), Los Angeles, California, United States of America
| | - Melissa M. Kelley
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, United States of America
| | - James Matsunaga
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, United States of America
- Department of Medicine, David Geffen School of Medicine at University of California Los Angeles (UCLA), Los Angeles, California, United States of America
| | - Jane T. Babbitt
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, United States of America
- Department of Medicine, David Geffen School of Medicine at University of California Los Angeles (UCLA), Los Angeles, California, United States of America
| | - Michael S. Lewis
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, United States of America
| | | | - David A. Haake
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, United States of America
- Department of Medicine, David Geffen School of Medicine at University of California Los Angeles (UCLA), Los Angeles, California, United States of America
- Department of Urology, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
- Department of Microbiology, Immunology and Molecular Genetics, UCLA, Los Angeles, California, United States of America
- * E-mail:
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Cao Y, Faisal SM, Yan W, Chang YC, McDonough SP, Zhang N, Akey BL, Chang YF. Evaluation of novel fusion proteins derived from extracellular matrix binding domains of LigB as vaccine candidates against leptospirosis in a hamster model. Vaccine 2011; 29:7379-86. [PMID: 21803087 DOI: 10.1016/j.vaccine.2011.07.070] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 07/15/2011] [Accepted: 07/17/2011] [Indexed: 10/17/2022]
Abstract
Leptospira binds to host extracellular matrix (ECM) through surface exposed outer membrane proteins called adhesin in order to initiate infection. Of various adhesins present on the surface of the spirochete, Leptospira-immunoglobulin like proteins (Lig proteins) and LipL32 are most abundant, widely distributed among pathogenic serovars and well characterized. Various fragments of Lig proteins (Ligcon4, Ligcon4-7.5, LigBcen2) and C-terminus fragment of LipL32 all of that bind to host ECM were fused, expressed and purified in soluble form as fusion proteins. Four week hamsters were immunized subcutaneously with various fusion proteins emulsified in EMULSIGEN-D adjuvant and subsequently boosted at 3 weeks. The protective efficacy of these novel fusion proteins was evaluated against subsequent challenge with highly virulent L. interrogans serovar Pomona (MLD50-100). Our results indicate that fusion protein based vaccine induced significant protection against acute infection with respect to PBS-adjuvant vaccinated controls as revealed by enhanced survival and reduced pulmonary hemorrhage. Moreover, the protection mediated by these novel proteins was higher than that of conserved region of Lig protein (Ligcon, established protective antigen) and correlated to the level of antibodies. LipL32 failed to impart significant protection, however fusing its immunogenic C-terminus domain to Lig fragments slightly delayed the morbidity of the infected animals. Our results demonstrate that this novel strategy could be promising in developing effective subunit vaccine to combat this zoonotic infection.
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Affiliation(s)
- Yongguo Cao
- Department of Population medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, United States
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