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Barbosa LN, LIanes A, Madesh S, Fayne BN, Brangulis K, Linn-Peirano SC, Rajeev S. Enhancement of clinical signs in C3H/HeJ mice vaccinated with a highly immunogenic Leptospira methyl-accepting chemotaxis protein following challenge. PLoS Negl Trop Dis 2024; 18:e0012155. [PMID: 39312584 PMCID: PMC11449317 DOI: 10.1371/journal.pntd.0012155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 10/03/2024] [Accepted: 09/02/2024] [Indexed: 09/25/2024] Open
Abstract
Leptospirosis is the most widespread zoonosis and a life-threatening disease in humans and animals. Licensed killed whole-cell vaccines are available for animals; however, they do not offer heterologous protection, do not induce long-term protection, or prevent renal colonization. In this study, we characterized an immunogenic Leptospira methyl-accepting chemotaxis protein (MCP) identified through a reverse vaccinology approach, predicted its structure, and tested the protective efficacy of a recombinant MCP fragment in the C3H/HeJ mice model. The predicted structure of the full-length MCP revealed an architecture typical for topology class I MCPs. A single dose of MCP vaccine elicited a significant IgG antibody response in immunized mice compared to controls (P < 0.0001), especially the IgG1 and IgG2a subclasses. The vaccination with MCP, despite eliciting a robust immune response, did not protect mice from disease and renal colonization. However, survival curves significantly differed between groups, and the MCP-vaccinated group developed clinical signs faster than the control group. There were differences in gross and histopathological changes between the MCP-vaccinated and control groups. The factors leading to enhanced disease process in vaccinated animals need further investigation. We speculate that anti-MCP antibodies may block the MCP signaling cascade and may limit chemotaxis, preventing Leptospira from reaching its destination, but facilitating its maintenance and replication in the blood stream. Such a phenomenon may exist in endemic areas where humans are highly exposed to Leptospira antigens, and the presence of antibodies might lead to disease enhancement. The role of this protein in Leptospira pathogenesis should be further evaluated to comprehend the lack of protection and potential exacerbation of the disease process. The absence of immune correlates of protection from Leptospira infection is still a major limitation of this field and efforts to gather this knowledge are needed.
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Affiliation(s)
- Liana Nunes Barbosa
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Alejandro LIanes
- Centro de Biología Celular y Molecular de Enfermedades, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Panama City, Panama
| | - Swetha Madesh
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Bryanna Nicole Fayne
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee, United States of America
| | | | - Sarah C. Linn-Peirano
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Sreekumari Rajeev
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee, United States of America
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Kundu S, Shetty A, Gomes-Solecki M. Exposure to live saprophytic Leptospira before challenge with a pathogenic serovar prevents severe leptospirosis and promotes kidney homeostasis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.01.582981. [PMID: 38496604 PMCID: PMC10942337 DOI: 10.1101/2024.03.01.582981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Previous studies demonstrated that Leptospira biflexa, a saprophytic species, triggers innate immune responses in the host during early infection. This raised the question of whether these responses could suppress a subsequent challenge with pathogenic Leptospira. We inoculated C3H/HeJ mice with a single or a double dose of L. biflexa before challenge with a pathogenic serovar, L. interrogans serovar Copenhageni FioCruz (LIC). Pre-challenge exposure to L. biflexa did not prevent LIC dissemination and colonization of the kidney. However, it rescued weight loss and mouse survival thereby mitigating disease severity. Unexpectedly, there was correlation between rescue of overall health (weight gain, higher survival, lower kidney fibrosis marker ColA1) and higher shedding of LIC in urine. This stood in contrast to the L. biflexa unexposed LIC challenged control. Immune responses were dominated by increased frequency of effector T helper (CD4+) cells in spleen, as well as significant increases in serologic IgG2a. Our findings suggest that exposure to live saprophytic Leptospira primes the host to develop Th1 biased immune responses that prevent severe disease induced by a subsequent challenge with a pathogenic species. Thus, mice exposed to live saprophytic Leptospira before facing a pathogenic serovar may withstand infection with far better outcomes. Furthermore, a status of homeostasis may have been reached after kidney colonization that helps LIC complete its enzootic cycle.
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Affiliation(s)
- Suman Kundu
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Advait Shetty
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Maria Gomes-Solecki
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
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de Azevedo SS. Epidemiology of Leptospira sp. Infection: Current Status, Insights and Future Prospects. Microorganisms 2023; 12:22. [PMID: 38257849 PMCID: PMC10821098 DOI: 10.3390/microorganisms12010022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 12/19/2023] [Indexed: 01/24/2024] Open
Abstract
In recent decades, the scientific community has been faced with an increased risk of emerging or re-emerging zoonotic diseases, such as leptospirosis, mainly originating from anthropic actions [...].
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Affiliation(s)
- Sérgio Santos de Azevedo
- Academic Unit of Veterinary Medicine, Center for Rural Health and Technology, Federal University of Campina Grande, Patos 58708-110, Brazil
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4
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Varma VP, Kadivella M, Kavela S, Faisal SM. Leptospira Lipid A Is a Potent Adjuvant That Induces Sterilizing Immunity against Leptospirosis. Vaccines (Basel) 2023; 11:1824. [PMID: 38140228 PMCID: PMC10748165 DOI: 10.3390/vaccines11121824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 09/16/2023] [Accepted: 11/30/2023] [Indexed: 12/24/2023] Open
Abstract
Leptospirosis is a globally significant zoonotic disease. The current inactivated vaccine offers protection against specific serovars but does not provide complete immunity. Various surface antigens, such as Leptospira immunoglobulin-like proteins (LigA and LigB), have been identified as potential subunit vaccine candidates. However, these antigens require potent adjuvants for effectiveness. Bacterial lipopolysaccharides (LPSs), including lipid A, are a well-known immunostimulant, and clinical adjuvants often contain monophosphoryl lipid A (MPLA). Being less endotoxic, we investigated the adjuvant properties of lipid A isolated from L. interrogans serovar Pomona (PLA) in activating innate immunity and enhancing antigen-specific adaptive immune responses. PLA activated macrophages to a similar degree as MPLA, albeit at a higher dose, suggesting that it is less potent in stimulation than MPLA. Mice immunized with a variable portion of LigA (LAV) combined with alum and PLA (LAV-alum-PLA) exhibited significantly higher levels of LAV-specific humoral and cellular immune responses compared to alum alone but similar to those induced by alum-MPLA. The adjuvant activity of PLA resembles that of MPLA and is primarily achieved through the increased recruitment, activation, and uptake of antigens by innate immune cells. Furthermore, like MPLA, PLA formulation establishes a long-lasting memory response. Notably, PLA demonstrated superior potency than MPLA formulation and provided sterilizing immunity against the leptospirosis in a hamster model. Overall, our study sheds light on the adjuvant properties of Leptospira lipid A and offers promising avenues for developing LPS-based vaccines against this devastating zoonotic disease.
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Affiliation(s)
- Vivek P. Varma
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad 500032, India; (V.P.V.); (M.K.); (S.K.)
- Graduate Studies, Manipal Academy of Higher Education, Manipal 576104, India
| | - Mohammad Kadivella
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad 500032, India; (V.P.V.); (M.K.); (S.K.)
- Regional Centre for Biotechnology, Faridabad 121001, India
| | - Sridhar Kavela
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad 500032, India; (V.P.V.); (M.K.); (S.K.)
| | - Syed M. Faisal
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad 500032, India; (V.P.V.); (M.K.); (S.K.)
- Regional Centre for Biotechnology, Faridabad 121001, India
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Azevedo IR, Amamura TA, Isaac L. Human leptospirosis: In search for a better vaccine. Scand J Immunol 2023; 98:e13316. [PMID: 39008520 DOI: 10.1111/sji.13316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 07/03/2023] [Accepted: 07/05/2023] [Indexed: 07/17/2024]
Abstract
Leptospirosis is a neglected disease caused by bacteria of the genus Leptospira and is more prevalent in tropical and subtropical countries. This pathogen infects humans and other animals, responsible for the most widespread zoonosis in the world, estimated to be responsible for 60 000 deaths and 1 million cases per year. To date, commercial vaccines against human leptospirosis are available only in some countries such as Japan, China, Cuba and France. These vaccines prepared with inactivated Leptospira (bacterins) induce a short-term and serovar-specific immune response, with strong adverse side effects. To circumvent these limitations, several research groups are investigating new experimental vaccines in order to ensure that they are safe, efficient, and protect against several pathogenic Leptospira serovars, inducing sterilizing immunity. Most of these protocols use attenuated cultures, preparations after LPS removal, recombinant proteins or DNA from pathogenic Leptospira spp. The aim of this review was to highlight several promising vaccine candidates, considering their immunogenicity, presence in different pathogenic Leptospira serovars, their role in virulence or immune evasion and other factors.
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Affiliation(s)
- Isabela Resende Azevedo
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Thais Akemi Amamura
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Lourdes Isaac
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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Fernandes LGV, Teixeira AF, Nascimento ALTO. Evaluation of Leptospira interrogans knockdown mutants for LipL32, LipL41, LipL21, and OmpL1 proteins. Front Microbiol 2023; 14:1199660. [PMID: 37426019 PMCID: PMC10326724 DOI: 10.3389/fmicb.2023.1199660] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 06/05/2023] [Indexed: 07/11/2023] Open
Abstract
Introduction Leptospirosis is a worldwide zoonosis caused by pathogenic and virulent species of the genus Leptospira, whose pathophysiology and virulence factors remain widely unexplored. Recently, the application of CRISPR interference (CRISPRi) has allowed the specific and rapid gene silencing of major leptospiral proteins, favoring the elucidation of their role in bacterial basic biology, host-pathogen interaction and virulence. Episomally expressed dead Cas9 from the Streptococcus pyogenes CRISPR/Cas system (dCas9) and single-guide RNA recognize and block transcription of the target gene by base pairing, dictated by the sequence contained in the 5' 20-nt sequence of the sgRNA. Methods In this work, we tailored plasmids for silencing the major proteins of L. interrogans serovar Copenhageni strain Fiocruz L1-130, namely LipL32, LipL41, LipL21 and OmpL1. Double- and triple-gene silencing by in tandem sgRNA cassettes were also achieved, despite plasmid instability. Results OmpL1 silencing resulted in a lethal phenotype, in both L. interrogans and saprophyte L. biflexa, suggesting its essential role in leptospiral biology. Mutants were confirmed and evaluated regarding interaction with host molecules, including extracellular matrix (ECM) and plasma components, and despite the dominant abundance of the studied proteins in the leptospiral membrane, protein silencing mostly resulted in unaltered interactions, either because they intrinsically display low affinity to the molecules assayed or by a compensation mechanism, where other proteins could be upregulated to fill the niche left by protein silencing, a feature previously described for the LipL32 mutant. Evaluation of the mutants in the hamster model confirms the augmented virulence of the LipL32 mutant, as hinted previously. The essential role of LipL21 in acute disease was demonstrated, since the LipL21 knockdown mutants were avirulent in the animal model, and even though mutants could still colonize the kidneys, they were found in markedly lower numbers in the animals' liver. Taking advantage of higher bacterial burden in LipL32 mutant-infected organs, protein silencing was demonstrated in vivo directly in leptospires present in organ homogenates. Discussion CRISPRi is now a well-established, attractive genetic tool that can be applied for exploring leptospiral virulence factors, leading to the rational for designing more effective subunit or even chimeric recombinant vaccines.
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Affiliation(s)
- Luis G. V. Fernandes
- Laboratório de Desenvolvimento de Vacinas, Instituto Butantan, São Paulo, SP, Brazil
| | - Aline F. Teixeira
- Laboratório de Desenvolvimento de Vacinas, Instituto Butantan, São Paulo, SP, Brazil
| | - Ana L. T. O. Nascimento
- Laboratório de Desenvolvimento de Vacinas, Instituto Butantan, São Paulo, SP, Brazil
- Programa de Pos-Graduacao Interunidades em Biotecnologia, Instituto de Ciencias Biomedicas, São Paulo, Brazil
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Diving into the complexity of the spirochetal endoflagellum. Trends Microbiol 2023; 31:294-307. [PMID: 36244923 DOI: 10.1016/j.tim.2022.09.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/12/2022] [Accepted: 09/14/2022] [Indexed: 11/27/2022]
Abstract
Spirochaetes, a phylum that includes medically important pathogens such as the causative agents of Lyme disease, syphilis, and leptospirosis, are in many ways highly unique bacteria. Their cell morphology, subcellular organization, and metabolism reveal atypical features. Spirochetal motility is also singular, dependent on the presence of periplasmic flagella or endoflagella, inserted subterminally at cell poles and not penetrating the outer membrane and elongating outside the cell as in enterobacteria. In this review we present a comprehensive comparative genomics analysis of endoflagellar systems in spirochetes, highlighting recent findings on the flagellar basal body and filament. Continued progress in understanding the function and architecture of spirochetal flagella is uncovering paradigm-shifting mechanisms of bacterial motility.
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Vieira DS, Chaurasia R, Vinetz JM. Comparison of the PF07598-Encoded Virulence-Modifying Proteins of L. interrogans and L. borgpetersenii. Trop Med Infect Dis 2022; 8:14. [PMID: 36668921 PMCID: PMC9863803 DOI: 10.3390/tropicalmed8010014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 12/28/2022] Open
Abstract
Leptospirosis is an emerging infectious disease, with increasing frequency and severity of outbreaks, a changing epidemiology of populations at risk, and the emergence of new strains, serovars, serogroups, and species. Virulence-modifying (VM) proteins encoded by the PF07598 gene family are hypothesized to be Leptospira-secreted exotoxins that mediate the molecular and cellular pathogenesis of severe and fatal leptospirosis. If confirmed experimentally, this concept could revolutionize the treatment, diagnosis, prognosis, and vaccine-mediated prevention of leptospirosis by enabling a novel array of targeted interventions. VM proteins, as with other bacterial-secreted protein exotoxins, mediate their virulence effects by attaching to eukaryotic cells, competing with other microorganisms for limited resources in environmental niches, directly intoxicating target cells, and disrupting their function in the mammalian host. In contrast with the most pathogenic group of Lept ospira, particularly L. interrogans, whose genomes contain 12-15 PF07598 paralogs, strains of the livestock and human pathogen L. borgpetersenii have two PF07598 paralogs. Given the possible non-environmentally mediated transmission of some L. borgpetersenii strains and the much smaller number of VM proteins in this species, their role in infection and disease may well differ from other leptospiral species. Comparison of VM proteins from different clades of pathogenic Leptospira may deepen our understanding of leptospirosis's pathogenesis, leading to novel approaches to ameliorating Leptospira infection in humans and animals.
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Affiliation(s)
| | | | - Joseph M. Vinetz
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06510, USA
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Prapong S, Tansiri Y, Sritrakul T, Sripattanakul S, Sopitthummakhun A, Katzenmeier G, Hsieh CL, McDonough SP, Prapong T, Chang YF. Leptospira borgpetersenii Leucine-Rich Repeat Proteins Provide Strong Protective Efficacy as Novel Leptospiral Vaccine Candidates. Trop Med Infect Dis 2022; 8:tropicalmed8010006. [PMID: 36668913 PMCID: PMC9863753 DOI: 10.3390/tropicalmed8010006] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 12/16/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
Leucine-rich repeat (LRR) proteins are advocated for being assessed in vaccine development. Leptospiral LRR proteins were identified recently in silico from the genome of Leptospira borgpetersenii serogroup Sejroe, the seroprevalence of leptospiral infections of cattle in Thailand. Two LRR recombinant proteins, rKU_Sej_LRR_2012M (2012) and rhKU_Sej_LRR_2271 (2271), containing predicted immunogenic epitopes, were investigated for their cross-protective efficacies in an acute leptospirosis model with heterologous Leptospira serovar Pomona, though, strains from serogroup Sejroe are host-adapted to bovine, leading to chronic disease. Since serovar Pomona is frequently reported as seropositive in cattle, buffaloes, pigs, and dogs in Thailand and causes acute and severe leptospirosis in cattle by incidental infection, the serogroup Sejroe LRR proteins were evaluated for their cross-protective immunity. The protective efficacies were 37.5%, 50.0%, and 75.0% based on the survival rate for the control, 2012, and 2271 groups, respectively. Sera from 2012-immunized hamsters showed weak bactericidal action compared to sera from 2271-immunized hamsters (p < 0.05). Therefore, bacterial tissue clearances, inflammatory responses, and humoral and cell-mediated immune (HMI and CMI) responses were evaluated only in 2271-immunized hamsters challenged with virulent L. interrogans serovar Pomona. The 2271 protein induced prompt humoral immune responses (p < 0.05) and leptospiral tissue clearance, reducing tissue inflammation in immunized hamsters. In addition, protein 2271 and its immunogenic peptides stimulated splenocyte lymphoproliferation and stimulated both HMI and CMI responses by activating Th1 and Th2 cytokine gene expression in vaccinated hamsters. Our data suggest that the immunogenic potential renders rhKU_Sej_LRR_2271 protein a promising candidate for the development of a novel cross-protective vaccine against animal leptospirosis.
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Affiliation(s)
- Siriwan Prapong
- 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 10900, Thailand
- Correspondence: ; Tel.: +66-871-264-148
| | - Yada Tansiri
- Faculty of Medicine, King Mongkut’s Institute of Technology Ladkrabang, Bangkok 10520, Thailand
| | - Tepyuda Sritrakul
- Department of Veterinary Public Health, Faculty of Veterinary Medicine, Kasetsart University, Kamphaengsaen Campus, Nakorn Pathom 73140, Thailand
| | - Sineenat Sripattanakul
- Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand
- The Interdisciplinary Graduate Program in Genetic Engineering, The Graduate School, Kasetsart University, Bangkok 10900, Thailand
| | - Aukkrimapann Sopitthummakhun
- Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand
- Center for Advanced Studies for Agriculture and Food (CASAF), Kasetsart University, Bangkok 10900, Thailand
| | - Gerd Katzenmeier
- Akkhraratchakumari Veterinary College, Walailak University, Nakhon Si Thammarat 80160, Thailand
| | - Chin-Lin Hsieh
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Sean P. McDonough
- Department of Biomedical Science, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Teerasak Prapong
- Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand
| | - Yung-Fu Chang
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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Belsare AV, Gompper ME, Mason M, Munoz-Zanzi C. Investigating Leptospira dynamics in a multi-host community using an agent-based modelling approach. Transbound Emerg Dis 2022; 69:3780-3789. [PMID: 36315387 DOI: 10.1111/tbed.14750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 10/24/2022] [Accepted: 10/26/2022] [Indexed: 11/05/2022]
Abstract
Leptospirosis, a neglected bacterial zoonosis, is a global public health issue disproportionately affecting impoverished communities such as urban slums in the developing world. A variety of animal species, including peridomestic rodents and dogs, can be infected with different strains of leptospirosis. Humans contract leptospirosis via exposure to water or soil contaminated with the urine of infected animals. Due to the unavailability of safe and effective vaccines, preventive strategies mainly focus on minimizing human exposure to contaminated environment. In marginalized communities, this approach is ineffective due to infrastructure deficiencies and the difficulties in implementing sanitation and hygiene practices. Moreover, continuing the expansion of urban slums worldwide will likely contribute to the increase in outbreaks of leptospirosis. Effective prevention of leptospirosis outbreaks will therefore require a thorough understanding of Leptospira transmission dynamics in impoverished, high-density settings. We developed the agent-based model MHMSLeptoDy to investigate Leptospira dynamics in a realistic, in silico high-density community of rodents, dogs and human hosts, and two host-adapted Leptospira strains. Virtual explorations using MHMSLeptoDy were undertaken to evaluate alternate interventions and to assess the zoonotic transmission risk of leptospirosis. A key finding from model explorations is that rodents are the main contributors of rodent-adapted as well as dog-adapted strains in the environment, whereas dogs play an important role in distributing the rodent-adapted strain. Alternate leptospirosis control strategies can be evaluated using the open-source, customizable agent-based model, MHMSLeptoDy. This modelling approach provides a sophisticated mechanism to quantitatively evaluate nuanced intervention strategies and inform the design of rational, locally relevant leptospirosis control programmes.
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Affiliation(s)
| | - Matthew E Gompper
- Department of Fish, Wildlife and Conservation Ecology, New Mexico State University, Las Cruces, New Mexico, USA
| | - Meghan Mason
- Department of Public Health, St. Catherine University, St. Paul, Minnesota, USA
| | - Claudia Munoz-Zanzi
- Division of Environmental Health Sciences, School of Public Health, University of Minnesota, Minneapolis, Minnesota, USA
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11
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Maia MAC, Bettin EB, Barbosa LN, de Oliveira NR, Bunde TT, Pedra ACK, Rosa GA, da Rosa EEB, Seixas Neto ACP, Grassmann AA, McFadden J, Dellagostin OA, McBride AJA. Challenges for the development of a universal vaccine against leptospirosis revealed by the evaluation of 22 vaccine candidates. Front Cell Infect Microbiol 2022; 12:940966. [PMID: 36275031 PMCID: PMC9586249 DOI: 10.3389/fcimb.2022.940966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Leptospirosis is a neglected disease of man and animals that affects nearly half a million people annually and causes considerable economic losses. Current human vaccines are inactivated whole-cell preparations (bacterins) of Leptospira spp. that provide strong homologous protection yet fail to induce a cross-protective immune response. Yearly boosters are required, and serious side-effects are frequently reported so the vaccine is licensed for use in humans in only a handful of countries. Novel universal vaccines require identification of conserved surface-exposed epitopes of leptospiral antigens. Outer membrane β-barrel proteins (βb-OMPs) meet these requirements and have been successfully used as vaccines for other diseases. We report the evaluation of 22 constructs containing protein fragments from 33 leptospiral βb-OMPs, previously identified by reverse and structural vaccinology and cell-surface immunoprecipitation. Three-dimensional structures for each leptospiral βb-OMP were predicted by I-TASSER. The surface-exposed epitopes were predicted using NetMHCII 2.2 and BepiPred 2.0. Recombinant constructs containing regions from one or more βb-OMPs were cloned and expressed in Escherichia coli. IMAC-purified recombinant proteins were adsorbed to an aluminium hydroxide adjuvant to produce the vaccine formulations. Hamsters (4-6 weeks old) were vaccinated with 2 doses containing 50 – 125 μg of recombinant protein, with a 14-day interval between doses. Immunoprotection was evaluated in the hamster model of leptospirosis against a homologous challenge (10 – 20× ED50) with L. interrogans serogroup Icterohaemorrhagiae serovar Copenhageni strain Fiocruz L1-130. Of the vaccine formulations, 20/22 were immunogenic and induced significant humoral immune responses (IgG) prior to challenge. Four constructs induced significant protection (100%, P < 0.001) and sterilizing immunity in two independent experiments, however, this was not reproducible in subsequent evaluations (0 – 33.3% protection, P > 0.05). The lack of reproducibility seen in these challenge experiments and in other reports in the literature, together with the lack of immune correlates and commercially available reagents to characterize the immune response, suggest that the hamster may not be the ideal model for evaluation of leptospirosis vaccines and highlight the need for evaluation of alternative models, such as the mouse.
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Affiliation(s)
- Mara A. C. Maia
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Everton B. Bettin
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Liana N. Barbosa
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Natasha R. de Oliveira
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Tiffany T. Bunde
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Ana Carolina K. Pedra
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Guilherme A. Rosa
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Elias E. B. da Rosa
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Amilton C. P. Seixas Neto
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - André A. Grassmann
- Department of Medicine, University of Connecticut Health, Farmington, CT, United States
| | - Johnjoe McFadden
- School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Odir A. Dellagostin
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Alan J. A. McBride
- Biotechnology Unit, Technological Development Centre, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
- School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
- *Correspondence: Alan J. A. McBride,
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Chaurasia R, Salovey A, Guo X, Desir G, Vinetz JM. Vaccination With Leptospira interrogans PF07598 Gene Family-Encoded Virulence Modifying Proteins Protects Mice From Severe Leptospirosis and Reduces Bacterial Load in the Liver and Kidney. Front Cell Infect Microbiol 2022; 12:926994. [PMID: 35837473 PMCID: PMC9274288 DOI: 10.3389/fcimb.2022.926994] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 05/24/2022] [Indexed: 12/29/2022] Open
Abstract
The molecular and cellular pathogenesis of leptospirosis remains poorly understood. Based on comparative bacterial genomics data, we recently identified the hypothetical PF07598 gene family as encoding secreted exotoxins (VM proteins) that mediate cytotoxicity in vitro. To address whether VM proteins mediate in vivo leptospirosis pathogenesis, we tested the hypothesis that VM protein immunization of mice would protect against lethal challenge infection and reduce bacterial load in key target organs. C3H/HeJ mice were immunized with recombinant E. coli-produced, endotoxin-free, leptospiral VM proteins (derived from L. interrogans serovar Lai) in combination with the human-compatible adjuvant, glucopyranoside lipid A/squalene oil-in-water. Mice receiving full length recombinant VM proteins were protected from lethal challenge infection by L. interrogans serovar Canicola and had a 3-4 log10 reduction in bacterial load in the liver and kidney. These experiments show that immunization with recombinant VM proteins prevents leptospirosis clinical pathogenesis and leads to markedly reduced key target organ infection in this animal model. These data support the role of leptospiral VM proteins as virulence factors and suggest the possibility that a VM protein-based, serovar-independent, pan-leptospirosis vaccine may be feasible.
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Affiliation(s)
- Reetika Chaurasia
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Aryeh Salovey
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Xiaojia Guo
- Section of Nephrology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Gary Desir
- Section of Nephrology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Joseph M. Vinetz
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
- *Correspondence: Joseph M. Vinetz,
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13
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Cruz JS, Nery N, Sacramento GA, Victoriano R, Montenegro ALS, Santana JO, Costa F, Ko AI, Reis MG, Wunder EA. Biannual and Quarterly Comparison Analysis of Agglutinating Antibody Kinetics on a Subcohort of Individuals Exposed to Leptospira interrogans in Salvador, Brazil. Front Med (Lausanne) 2022; 9:862378. [PMID: 35492362 PMCID: PMC9048256 DOI: 10.3389/fmed.2022.862378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 03/21/2022] [Indexed: 11/13/2022] Open
Abstract
IntroductionLeptospirosis is a zoonosis with a worldwide spread that leads to clinical manifestations ranging from asymptomatic infection to a life-threatening disease. The immune response is predominantly humoral mediated limited to the infecting serovar. Individuals living in an area endemic for leptospirosis are often exposed to an environment contaminated with leptospires and there is a paucity of information on naturally acquired immunity. In the present study, we evaluated the kinetics of agglutinating antibodies in individuals from an endemic area for leptospirosis in Salvador, Brazil comparing two different intersample collection times.MethodsBetween 2017–2018, we carried out a biannual prospective cohort with 2,086 individuals living in an endemic area for leptospirosis in Salvador, Brazil. To compare agglutinating antibody kinetics using microscopic agglutination test (MAT) with different collection times, a subcohort of 72 individuals with quarterly follow-up was carried out in parallel.ResultsThe results revealed that using a shorter time for intersample collection led to the detection of a higher number of infections and reinfection events. Furthermore, we observed a higher rate of titer decay indicating partial and short protection. However, there was no indication of major changes in risk factors for the disease.ConclusionsWe evaluated antibody kinetics among residents of an endemic area for leptospirosis comparing two sample collection times. The constant exposure to the contaminated environment increases the risk for leptospirosis infection with reinfection events being more common than expected. This indicates that the burden of leptospirosis might be underestimated by serological surveys, and further studies are necessary to better characterize the humoral response after infection.
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Affiliation(s)
- Jaqueline S. Cruz
- Laboratório de Patologia e Biologia Molecular, Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil
| | - Nivison Nery
- Laboratório de Patologia e Biologia Molecular, Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil
- Instituto de Saúde Coletiva, Universidade Federal da Bahia, Salvador, Brazil
| | | | - Renato Victoriano
- Instituto de Saúde Coletiva, Universidade Federal da Bahia, Salvador, Brazil
| | - Albino L. S. Montenegro
- Laboratório de Patologia e Biologia Molecular, Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil
| | - Juliet O. Santana
- Laboratório de Patologia e Biologia Molecular, Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil
- Departamento de Geografia, Instituto de Geociências, Universidade Federal da Bahia, Salvador, Brazil
| | - Federico Costa
- Laboratório de Patologia e Biologia Molecular, Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil
- Instituto de Saúde Coletiva, Universidade Federal da Bahia, Salvador, Brazil
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States
| | - Albert I. Ko
- Laboratório de Patologia e Biologia Molecular, Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States
| | - Mitermayer G. Reis
- Laboratório de Patologia e Biologia Molecular, Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States
- Departamento de Medicina e Patologia Legal, Faculdade de Medicina da Bahia, Universidade Federal da Bahia, Salvador, Brazil
| | - Elsio A. Wunder
- Laboratório de Patologia e Biologia Molecular, Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States
- *Correspondence: Elsio A. Wunder Jr.
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14
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Fernandes LGV, Putz EJ, Stasko J, Lippolis JD, Nascimento ALTO, Nally JE. Evaluation of LipL32 and LigA/LigB Knockdown Mutants in Leptospira interrogans Serovar Copenhageni: Impacts to Proteome and Virulence. Front Microbiol 2022; 12:799012. [PMID: 35185824 PMCID: PMC8847714 DOI: 10.3389/fmicb.2021.799012] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 12/17/2021] [Indexed: 01/14/2023] Open
Abstract
Leptospirosis is a worldwide zoonosis caused by pathogenic species of the genus Leptospira. The recent application of CRISPR interference (CRISPRi) to Leptospira facilitates targeted gene silencing and provides a new tool to investigate pathogenic mechanisms of leptospirosis. CRISPRi relies on the expression of a catalytically “dead” Cas9 (dCas9) and a single-guide RNA (sgRNA). Previously, our group generated a LipL32 and a double LigA/LigB (LigAB) mutant, which, in the current study, are characterized by whole-cell proteomics in comparison with control leptospires harboring plasmid expressing dCas9 alone. Comparison of control and LigAB mutant leptospires identified 46 significantly differentially expressed (DE) proteins, including 27 proteins that were less abundant and 19 proteins that were more abundant in the LigAB mutant compared with the control. Comparison of the control and LipL32 mutant leptospires identified 243 DE proteins, of which 84 proteins were more abundant and 159 were less abundant in the LipL32 mutant strain. Significantly increased amounts of known virulence impactors and surface membrane receptors, including LipL45, LipL31, LigB, and LipL41, were identified. The virulence of LipL32 and LigAB mutants were evaluated in the hamster model of leptospirosis; the LigAB mutant was unable to cause acute disease although mutant leptospires could still be recovered from target organs, albeit at a significantly lower bacterial burden (<850 and <16-fold in liver and kidney, respectively, in comparison with control), indicating attenuation of virulence and a shift to chronic bacterial persistence. Notably, the LipL32 mutant displayed augmented virulence as evidenced by early onset of clinical symptoms and increased numbers of circulating foamy macrophages. Validation of LipL32 and LigAB mutants recovered from liver and kidney in the presence or absence of antibiotic selection revealed high plasmid stability and, by extension, gene silencing in vivo. Collectively, this work emphasizes the advantages and feasibility of using CRISPRi technology to evaluate and characterize virulence factors of leptospires and their respective host–pathogen interactions in animal models of leptospirosis. Importantly, it also provides insight into the requirements of LigA and LigB for acute disease and explores the impact of silencing expression of lipL32, which resulted in substantial changes in amounts of outer membrane proteins.
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Affiliation(s)
- Luis G V Fernandes
- Infectious Bacterial Diseases Research Unit, USDA Agricultural Research Service, National Animal Disease Center, Ames, IA, United States.,Laboratório de Desenvolvimento de Vacinas, Instituto Butantan, São Paulo, Brazil
| | - Ellie J Putz
- Infectious Bacterial Diseases Research Unit, USDA Agricultural Research Service, National Animal Disease Center, Ames, IA, United States
| | - Judith Stasko
- Infectious Bacterial Diseases Research Unit, USDA Agricultural Research Service, National Animal Disease Center, Ames, IA, United States
| | - John D Lippolis
- Ruminant Diseases and Immunology Research Unit, USDA Agricultural Research Service, National Animal Disease Center, Ames, IA, United States
| | - Ana L T O Nascimento
- Laboratório de Desenvolvimento de Vacinas, Instituto Butantan, São Paulo, Brazil
| | - Jarlath E Nally
- Infectious Bacterial Diseases Research Unit, USDA Agricultural Research Service, National Animal Disease Center, Ames, IA, United States
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15
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Barazzone GC, Teixeira AF, Azevedo BOP, Damiano DK, Oliveira MP, Nascimento ALTO, Lopes APY. Revisiting the Development of Vaccines Against Pathogenic Leptospira: Innovative Approaches, Present Challenges, and Future Perspectives. Front Immunol 2022; 12:760291. [PMID: 35046936 PMCID: PMC8761801 DOI: 10.3389/fimmu.2021.760291] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 11/16/2021] [Indexed: 12/12/2022] Open
Abstract
Human vaccination against leptospirosis has been relatively unsuccessful in clinical applications despite an expressive amount of vaccine candidates has been tested over years of research. Pathogenic Leptospira encompass a great number of serovars, most of which do not cross-react, and there has been a lack of genetic tools for many years. These obstacles have hampered the understanding of the bacteria's biology and, consequently, the identification of an effective antigen. Thus far, many approaches have been used in an attempt to find a cost-effective and broad-spectrum protective antigen(s) against the disease. In this extensive review, we discuss several strategies that have been used to develop an effective vaccine against leptospirosis, starting with Leptospira-inactivated bacterin, proteins identified in the genome sequences of pathogenic Leptospira, including reverse vaccinology, plasmid DNA, live vaccines, chimeric multi-epitope, and toll- and nod-like receptors agonists. This overview should be able to guide scientists working in the field to select potential antigens and to choose the appropriate formulation to administer the candidates.
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Affiliation(s)
- Giovana C. Barazzone
- Laboratório de Desenvolvimento de Vacinas, Instituto Butantan, São Paulo, Brazil
- Programa de Pós-Graduação Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo (USP), São Paulo, Brazil
| | - Aline F. Teixeira
- Laboratório de Desenvolvimento de Vacinas, Instituto Butantan, São Paulo, Brazil
| | - Bruna O. P. Azevedo
- Laboratório de Desenvolvimento de Vacinas, Instituto Butantan, São Paulo, Brazil
- Programa de Pós-Graduação Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo (USP), São Paulo, Brazil
| | - Deborah K. Damiano
- Laboratório de Desenvolvimento de Vacinas, Instituto Butantan, São Paulo, Brazil
- Programa de Pós-Graduação Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo (USP), São Paulo, Brazil
| | - Marcos P. Oliveira
- Laboratório de Desenvolvimento de Vacinas, Instituto Butantan, São Paulo, Brazil
- Programa de Pós-Graduação Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo (USP), São Paulo, Brazil
| | - Ana L. T. O. Nascimento
- Laboratório de Desenvolvimento de Vacinas, Instituto Butantan, São Paulo, Brazil
- Programa de Pós-Graduação Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo (USP), São Paulo, Brazil
| | - Alexandre P. Y. Lopes
- Laboratório de Desenvolvimento de Vacinas, Instituto Butantan, São Paulo, Brazil
- Programa de Pós-Graduação Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo (USP), São Paulo, Brazil
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16
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Phoka T, Techawiwattanaboon T, Sangjun N, Komanee P, Murray GL, Wongratanacheewin Sermswan R, Adler B, Patarakul K. Identification of in vivo expressed proteins in live attenuated lipopolysaccharide mutant that mediates heterologous protection against Leptospira spp. Vet Microbiol 2021; 262:109220. [PMID: 34509026 DOI: 10.1016/j.vetmic.2021.109220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 08/28/2021] [Indexed: 10/20/2022]
Abstract
Leptospirosis vaccines that elicit broad protection against a range of pathogenic Leptospira spp. would overcome a major drawback of currently licensed bacterin vaccines. Live attenuated vaccine produced from a lipopolysaccharide (LPS) mutant strain of L. interrogans serovar Manilae M1352 (Live M1352) stimulated better protective efficacy than heat killed M1352 (HK M1352) against a heterologous challenge with L. interrogans serovar Pomona. To identify antigens of Live M1352 potentially responsible for cross protection, in vivo-induced antigen technology (IVIAT), a powerful tool to identify in vivo-induced (ivi) genes expressed during infection, was employed in this study. Pooled sera from hamsters immunized with Live M1352 were sequentially adsorbed with various preparations of in vitro grown M1352. The pre-adsorbed sera were used to screen a genomic expression library of M1352. Nineteen strongly reactive clones were selected for DNA sequencing. These ivi genes are conserved in most Leptospira strains. Four selected genes including LIMLP_04965 (tolB), LIMLP_01535, LIMLP_06785 (fliI), and LIMLP_14930 were confirmed for their upregulated expression in kidneys of infected hamsters by RT-qPCR, suggesting their role in leptospiral infection. These ivi proteins represent potential targets for vaccine candidates that warrant further investigation for their protective efficacy.
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Affiliation(s)
- Theerapat Phoka
- Medical Microbiology, Interdisciplinary and International Program, Graduate School, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Teerasit Techawiwattanaboon
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, 10330, Thailand; Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Noppadon Sangjun
- Armed Force Research Institute of Medical Sciences (AFRIMS), Bangkok, 10400, Thailand
| | - Pat Komanee
- Armed Force Research Institute of Medical Sciences (AFRIMS), Bangkok, 10400, Thailand
| | - Gerald L Murray
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, VIC, 3800, Australia; The Royal Women's Hospital, Parkville, VIC, 3052, Australia; Department of Obstetrics and Gynaecology, The University of Melbourne, Melbourne, VIC, 3052, Australia
| | - Rasana Wongratanacheewin Sermswan
- Melioidosis Research Center, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand; Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Ben Adler
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, VIC, 3800, Australia
| | - Kanitha Patarakul
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, 10330, Thailand; Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Bangkok, 10330, Thailand.
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Piredda I, Ponti MN, Piras A, Palmas B, Pintore P, Pedditzi A, Chisu V. New Insights on Leptospira Infections in a Canine Population from North Sardinia, Italy: A Sero-Epidemiological Study. BIOLOGY 2021; 10:biology10060507. [PMID: 34200298 PMCID: PMC8226461 DOI: 10.3390/biology10060507] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/04/2021] [Accepted: 06/05/2021] [Indexed: 11/16/2022]
Abstract
Leptospirosis is a widespread zoonosis recognized as a re-emerging infectious disease in a wide variety of animal species, including humans and dogs. No data exist regarding the presence of Leptospira species in the canine population of Sardinia Island. This study reports the first sero-survey for leptospirosis in kennel and owned dogs from six areas of the north of Sardinia. Sera from 1296 dogs were tested by microscopic agglutination test (MAT) specific for nine different serovars that are known to be well widespread in the Mediterranean environment. Moreover, kidney homogenates from rodents collected from the study area were also analyzed by LipL32 real-time PCR and multi-locus sequence type (MLST) on the basis of the analysis of seven concatenated loci. A total of 13% of the examined sera (95%CI: 11-15) tested positive for one or more serovars of Leptospira MAT detected; antibodies for serogroup Icterohaemorrhagiae (57%; 95%CI: 49-65) were the most common, followed by serovars Bratislava (22%; 95%CI: 16-28), Canicola (14%; 95%CI: 9-19), and Grippotyphosa (7%; 95%CI: 3-11). MLST analyses on isolates from rodents identified L. interrogans and L. borgpetersenii genomospecies. Different serovars belonging to pathogenic Leptospira serogroups are circulating in dogs from the island. Moreover, data obtained from rodents, indicated that rodents likely act as reservoir of spirochetes. Further sero-epidemiological studies are needed in order to obtain data from other collection sites in Sardinia and to increase the information on Leptospira species circulating in this area.
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Affiliation(s)
- Ivana Piredda
- Istituto Zooprofilattico Sperimentale della Sardegna, Department of Animal Health, Laboratory of Seroimmunology, 07100 Sassari, Italy; (M.N.P.); (B.P.); (P.P.); (A.P.); (V.C.)
- Correspondence: ; Tel.: +39-079-289-2329
| | - Maria Nicoletta Ponti
- Istituto Zooprofilattico Sperimentale della Sardegna, Department of Animal Health, Laboratory of Seroimmunology, 07100 Sassari, Italy; (M.N.P.); (B.P.); (P.P.); (A.P.); (V.C.)
| | - Angela Piras
- Azienda Socio Sanitaria Locale, Azienda Tutela Salute, 09047 Cagliari, Italy;
| | - Bruna Palmas
- Istituto Zooprofilattico Sperimentale della Sardegna, Department of Animal Health, Laboratory of Seroimmunology, 07100 Sassari, Italy; (M.N.P.); (B.P.); (P.P.); (A.P.); (V.C.)
| | - Pierangela Pintore
- Istituto Zooprofilattico Sperimentale della Sardegna, Department of Animal Health, Laboratory of Seroimmunology, 07100 Sassari, Italy; (M.N.P.); (B.P.); (P.P.); (A.P.); (V.C.)
| | - Aureliana Pedditzi
- Istituto Zooprofilattico Sperimentale della Sardegna, Department of Animal Health, Laboratory of Seroimmunology, 07100 Sassari, Italy; (M.N.P.); (B.P.); (P.P.); (A.P.); (V.C.)
| | - Valentina Chisu
- Istituto Zooprofilattico Sperimentale della Sardegna, Department of Animal Health, Laboratory of Seroimmunology, 07100 Sassari, Italy; (M.N.P.); (B.P.); (P.P.); (A.P.); (V.C.)
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18
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Anti-Leptospira immunoglobulin profiling in mice reveals strain specific IgG and persistent IgM responses associated with virulence and renal colonization. PLoS Negl Trop Dis 2021; 15:e0008970. [PMID: 33705392 PMCID: PMC8007020 DOI: 10.1371/journal.pntd.0008970] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 03/29/2021] [Accepted: 02/23/2021] [Indexed: 12/14/2022] Open
Abstract
Leptospira interrogans is a pathogenic spirochete responsible for leptospirosis, a neglected, zoonotic reemerging disease. Humans are sensitive hosts and may develop severe disease. Some animal species, such as rats and mice can become asymptomatic renal carriers. More than 350 leptospiral serovars have been identified, classified on the basis of the antibody response directed against the lipopolysaccharide (LPS). Similarly to whole inactivated bacteria used as human vaccines, this response is believed to confer only short-term, serogroup-specific protection. The immune response of hosts against leptospires has not been thoroughly studied, which complicates the testing of vaccine candidates. In this work, we studied the immunoglobulin (Ig) profiles in mice infected with L. interrogans over time to determine whether this humoral response confers long-term protection after homologous challenge six months post-infection. Groups of mice were injected intraperitoneally with 2×107 leptospires of one of three pathogenic serovars (Manilae, Copenhageni or Icterohaemorrhagiae), attenuated mutants or heat-killed bacteria. Leptospira-specific immunoglobulin (IgA, IgM, IgG and 4 subclasses) produced in the first weeks up to 6 months post-infection were measured by ELISA. Strikingly, we found sustained high levels of IgM in mice infected with the pathogenic Manilae and Copenhageni strains, both colonizing the kidney. In contrast, the Icterohaemorrhagiae strain did not lead to kidney colonization, even at high dose, and triggered a classical IgM response that peaked at day 8 post-infection and disappeared. The virulent Manilae and Copenhageni serovars elicited high levels and similar profiles of IgG subclasses in contrast to Icterohaemorrhagiae strains that stimulated weaker antibody responses. Inactivated heat-killed Manilae strains elicited very low responses. However, all mice pre-injected with leptospires challenged with high doses of homologous bacteria did not develop acute leptospirosis, and all antibody responses were boosted after challenge. Furthermore, we showed that 2 months post-challenge, mice pre-infected with the attenuated M895 Manilae LPS mutant or heat-killed bacterin were completely protected against renal colonization. In conclusion, we observed a sustained IgM response potentially associated with chronic leptospiral renal infection. We also demonstrated in mice different profiles of protective and cross-reactive antibodies after L. interrogans infection, depending on the serovar and virulence of strains. Leptospira interrogans is a pathogenic spirochete responsible for leptospirosis, a neglected zoonotic reemerging disease. The immune response of hosts against these bacteria has not been thoroughly studied. Here, we studied over 6 months the antibody profiles in mice infected with L. interrogans and determined whether this humoral response confers long-term protection after homologous challenge six months after primary infection. Groups of mice were infected intraperitoneally with 2×107 bacteria of one of three different pathogenic serovars (Manilae, Copenhageni and Icterohaemorrhagiae) and some corresponding attenuated avirulent mutants. We measured by ELISA each type of Leptospira-specific immunoglobulin (Ig) (IgA, IgM, IgG and 4 subclasses) produced in the first weeks up to 6 months post-infection and studied their cross-reactivities among serovars. We showed different profiles of antibody response after L. interrogans challenge in mice, depending on the serovar and virulence of strains. However, all infected mice, including the ones harboring low antibody levels, like mice vaccinated with an inactivated, heat-killed strain, were protected against leptospirosis after challenge. Notably, we also showed an unusual sustained IgM response associated with chronic leptospiral colonization. Altogether, this long-term immune protection is different from what is known in humans and warrants further investigation.
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