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Silva AC, Almeida PP, Fietto JLR, Oliveira LL, Marques-da-Silva EA. Development of a new assay for quantification of parasite load of intracellular Leishmania sp. in macrophages using flow cytometry. Cytometry A 2024; 105:382-387. [PMID: 38410875 DOI: 10.1002/cyto.a.24831] [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: 10/03/2023] [Revised: 12/26/2023] [Accepted: 02/12/2024] [Indexed: 02/28/2024]
Abstract
Finding novel methodologies that enhance the precision, agility, and standardization of drug discovery is crucial for studying leishmaniasis. The slide count is the technique most used to assess the leishmanicidal effect of a given drug in vitro. Despite being consolidated in the scientific environment, it presents several difficulties in its execution, assessment, and results. In addition to being laborious, this technique takes time, both for the preparation of the material for analysis and for the counting itself. Our research group suggests a fresh approach to address this requirement, which involves utilizing nuclear labeling with propidium iodide and flow cytometry to determine the quantity of Leishmania sp. parasites present in macrophages in vitro. Our results show that the fluorescence of infected samples increases as the infection rate increases. Using Pearson's Correlation analysis, it was possible to establish a correlation coefficient (Pearson r = 0.9473) that was strongly positive, linear, and directly proportional to the fluorescence and infection rate variables. Thus, it is possible to infer a mathematical equation through linear regression to estimate the number of parasites in each sample using the Relative Fluorescence Units (RFU) values. This new methodology opens space for the possibility of using this methodological resource in the in vitro quantification of Leishmania in macrophages.
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Affiliation(s)
- Adriana C Silva
- Department of General Biology, Federal University of Viçosa, Viçosa, Minas Gerais, Brazil
| | - Palloma P Almeida
- Department of General Biology, Federal University of Viçosa, Viçosa, Minas Gerais, Brazil
| | - Juliana L R Fietto
- Department of Biochemistry, Federal University of Viçosa, Viçosa, Minas Gerais, Brazil
| | - Leandro L Oliveira
- Department of General Biology, Federal University of Viçosa, Viçosa, Minas Gerais, Brazil
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Seyed N, Taheri T, Rafati S. Live attenuated-nonpathogenic Leishmania and DNA structures as promising vaccine platforms against leishmaniasis: innovations can make waves. Front Microbiol 2024; 15:1326369. [PMID: 38633699 PMCID: PMC11021776 DOI: 10.3389/fmicb.2024.1326369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Accepted: 03/12/2024] [Indexed: 04/19/2024] Open
Abstract
Leishmaniasis is a vector-borne disease caused by the protozoan parasite of Leishmania genus and is a complex disease affecting mostly tropical regions of the world. Unfortunately, despite the extensive effort made, there is no vaccine available for human use. Undoubtedly, a comprehensive understanding of the host-vector-parasite interaction is substantial for developing an effective prophylactic vaccine. Recently the role of sandfly saliva on disease progression has been uncovered which can make a substantial contribution in vaccine design. In this review we try to focus on the strategies that most probably meet the prerequisites of vaccine development (based on the current understandings) including live attenuated/non-pathogenic and subunit DNA vaccines. Innovative approaches such as reverse genetics, CRISP/R-Cas9 and antibiotic-free selection are now available to promisingly compensate for intrinsic drawbacks associated with these platforms. Our main goal is to call more attention toward the prerequisites of effective vaccine development while controlling the disease outspread is a substantial need.
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Affiliation(s)
- Negar Seyed
- Department of Immunotherapy and Leishmania Vaccine Research, Pasteur Institute of Iran, Tehran, Iran
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3
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Khandibharad S, Singh S. Synthetic biology for combating leishmaniasis. Front Microbiol 2024; 15:1338749. [PMID: 38362504 PMCID: PMC10867266 DOI: 10.3389/fmicb.2024.1338749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 01/08/2024] [Indexed: 02/17/2024] Open
Abstract
Leishmaniasis is a neglected tropical disease caused by protozoan parasites of the Leishmania genus. Despite the efforts to control and treat the disease, it still remains a major public health problem in many countries. Synthetic biology is a rapidly evolving interdisciplinary field that combines biology, engineering, and computer science to design and construct novel biological systems. In recent years, synthetic biology approaches have shown great promise for developing new and effective strategies to combat leishmaniasis. In this perspective, we summarize the recent advances in the use of synthetic biology for the development of vaccines, diagnostic tools, and novel therapeutics for leishmaniasis.
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Affiliation(s)
| | - Shailza Singh
- Systems Medicine Laboratory, National Centre for Cell Science, Pune, India
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Moreira POL, Nogueira PM, Monte-Neto RL. Next-Generation Leishmanization: Revisiting Molecular Targets for Selecting Genetically Engineered Live-Attenuated Leishmania. Microorganisms 2023; 11:microorganisms11041043. [PMID: 37110466 PMCID: PMC10145799 DOI: 10.3390/microorganisms11041043] [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: 03/18/2023] [Revised: 04/07/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023] Open
Abstract
Despite decades of research devoted to finding a vaccine against leishmaniasis, we are still lacking a safe and effective vaccine for humans. Given this scenario, the search for a new prophylaxis alternative for controlling leishmaniasis should be a global priority. Inspired by leishmanization-a first generation vaccine strategy where live L. major parasites are inoculated in the skin to protect against reinfection-live-attenuated Leishmania vaccine candidates are promising alternatives due to their robust elicited protective immune response. In addition, they do not cause disease and could provide long-term protection upon challenge with a virulent strain. The discovery of a precise and easy way to perform CRISPR/Cas-based gene editing allowed the selection of safer null mutant live-attenuated Leishmania parasites obtained by gene disruption. Here, we revisited molecular targets associated with the selection of live-attenuated vaccinal strains, discussing their function, their limiting factors and the ideal candidate for the next generation of genetically engineered live-attenuated Leishmania vaccines to control leishmaniasis.
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Affiliation(s)
- Paulo O L Moreira
- Biotechnology Applied to Pathogens (BAP), Instituto René Rachou, Fundação Oswaldo Cruz, Fiocruz Minas, Belo Horizonte 30190-009, Brazil
| | - Paula M Nogueira
- Biotechnology Applied to Pathogens (BAP), Instituto René Rachou, Fundação Oswaldo Cruz, Fiocruz Minas, Belo Horizonte 30190-009, Brazil
| | - Rubens L Monte-Neto
- Biotechnology Applied to Pathogens (BAP), Instituto René Rachou, Fundação Oswaldo Cruz, Fiocruz Minas, Belo Horizonte 30190-009, Brazil
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Augusto Sanches Roque G, Esteves Zorgi N, Janaína Soares Rocha F, Flóro E Silva M, Fernanda Araújo T, Ruiz Abánades D, Giorgio S. Evaluation of prime and prime-boost immunization strategies in BALB/c mice inoculated with Leishmania infantum transfected with toxic plasmids. Vaccine 2022; 40:4105-4115. [PMID: 35660330 DOI: 10.1016/j.vaccine.2022.05.063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 04/28/2022] [Accepted: 05/24/2022] [Indexed: 11/29/2022]
Abstract
The etiologic agents of visceral leishmaniasis are Leishmania infantum and Leishmania donovani. Despite the variety of drugs available to treat leishmaniasis, most lead to serious adverse effects, and resistance to these drugs has been reported. Currently, no leishmaniasis vaccine is available for humans. That is why the group developed transgenic L. infantum promastigote lines, which express toxic proteins after differentiation into amastigotes. That is why group developed the pFL-AMA plasmid and transfected it into L. Infantum promastigotes. This plasmid was expressed only in the amastigote form of the parasite. Sequences encoding toxic proteins (active bovine trypsin and egg avidin) were inserted in this plasmid, and the transfected parasites died after the differentiation process. In this study, two immunization protocols were performed in BALB/c mice: prime and prime-boost immunization prior to challenge with the wild-type L. infantum (WT). The parasite burdens in the spleen, liver, and bone marrow were evaluated to verify immunological protection. Histopathological analysis of the spleen and liver and the humoral immune response were also performed. The data showed that the parasite burden was reduced in prime-boosted mice in the spleen, liver, and bone marrow, indicating that mice immunized with two doses of the transfected parasites were satisfactorily protected. High levels of IgG, IgG1, and IgG2a antibodies were observed, as well as the presence of anti-inflammatory cytokine Interleukine-10 and pro-inflammatory cytokine Tumor Necrosis Factor-α (TNF-α) and Interferon-γ (IFN - γ) suggesting a Th1/Th2 mix response, in addition to the presence of multinucleated giant cells in the spleen and lymphocyte infiltration in the liver. Therefore, L. infantum transfected with a toxic plasmid is an excellent vaccine candidate against visceral leishmaniasis and the application of a boost before the challenge promotes greater protection against WT L. infantum infection.
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Affiliation(s)
| | - Nahiara Esteves Zorgi
- Animal Biology Department, Institute of Biology, State University of Campinas, Campinas, São Paulo, Brazil
| | | | - Marina Flóro E Silva
- Animal Biology Department, Institute of Biology, State University of Campinas, Campinas, São Paulo, Brazil
| | - Thalita Fernanda Araújo
- Animal Biology Department, Institute of Biology, State University of Campinas, Campinas, São Paulo, Brazil
| | - Daniel Ruiz Abánades
- Animal Biology Department, Institute of Biology, State University of Campinas, Campinas, São Paulo, Brazil
| | - Selma Giorgio
- Animal Biology Department, Institute of Biology, State University of Campinas, Campinas, São Paulo, Brazil.
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The History of Live Attenuated Centrin Gene-Deleted Leishmania Vaccine Candidates. Pathogens 2022; 11:pathogens11040431. [PMID: 35456106 PMCID: PMC9025045 DOI: 10.3390/pathogens11040431] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 02/08/2023] Open
Abstract
Leishmaniasis, caused by an infection of the Leishmania protozoa, is a neglected tropical disease and a major health problem in tropical and subtropical regions of the world, with approximately 350 million people worldwide at risk and 2 million new cases occurring annually. Current treatments for leishmaniasis are not highly efficacious and are associated with high costs, especially in low- and middle-income endemic countries, and high toxicity. Due to a surge in the incidence of leishmaniases worldwide, the development of new strategies such as a prophylactic vaccine has become a high priority. However, the ability of Leishmania to undermine immune recognition has limited our efforts to design safe and efficacious vaccines against leishmaniasis. Numerous antileishmanial vaccine preparations based on DNA, subunit, and heat-killed parasites with or without adjuvants have been tried in several animal models but very few have progressed beyond the experimental stage. However, it is known that people who recover from Leishmania infection can be protected lifelong against future infection, suggesting that a successful vaccine requires a controlled infection to develop immunologic memory and subsequent long-term immunity. Live attenuated Leishmania parasites that are non-pathogenic and provide a complete range of antigens similarly to their wild-type counterparts could evoke such memory and, thus, would be effective vaccine candidates. Our laboratory has developed several live attenuated Leishmania vaccines by targeted centrin gene disruptions either by homologous recombination or, more recently, by using genome editing technologies involving CRISPR-Cas9. In this review, we focused on the sequential history of centrin gene-deleted Leishmania vaccine development, along with the characterization of its safety and efficacy. Further, we discussed other major considerations regarding the transition of dermotropic live attenuated centrin gene-deleted parasites from the laboratory to human clinical trials.
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Abstract
Leishmaniasis is a zoonotic and vector-borne infectious disease that is caused by the genus Leishmania belonging to the trypanosomatid family. The protozoan parasite has a digenetic life cycle involving a mammalian host and an insect vector. Leishmaniasisis is a worldwide public health problem falling under the neglected tropical disease category, with over 90 endemic countries, and approximately 1 million new cases and 20,000 deaths annually. Leishmania infection can progress toward the development of species–specific pathologic disorders, ranging in severity from self-healing cutaneous lesions to disseminating muco-cutaneous and fatal visceral manifestations. The severity and the outcome of leishmaniasis is determined by the parasite’s antigenic epitope characteristics, the vector physiology, and most importantly, the immune response and immune status of the host. This review examines the nature of host–pathogen interaction in leishmaniasis, innate and adaptive immune responses, and various strategies that have been employed for vaccine development.
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Long-Term In Vitro Passaging Had a Negligible Effect on Extracellular Vesicles Released by Leishmania amazonensis and Induced Protective Immune Response in BALB/c Mice. J Immunol Res 2022; 2021:7809637. [PMID: 34977257 PMCID: PMC8720021 DOI: 10.1155/2021/7809637] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 11/07/2021] [Accepted: 11/25/2021] [Indexed: 12/03/2022] Open
Abstract
Depending on Leishmania species and the presence/absence of virulence factors, Leishmania extracellular vesicles (EVs) can differently stimulate host immune cells. This work is aimed at characterizing and evaluating the protective role of EVs released by Leishmania amazonensis promastigotes under different maintenance conditions. Initially, using a control strain, we standardized 26°C as the best release temperature to obtain EVs with a potential protective role in the experimental leishmaniasis model. Then, long-term (LT-P) promastigotes of L. amazonensis were obtained after long-term in vitro culture (100 in vitro passages). In vivo-derived (IVD-P) promastigotes of L. amazonensis were selected after 3 consecutive experimental infections in BALB/c mice. Those strains developed similar lesion sizes except for IVD-P at 8 weeks post infection. No differences in EV production were detected in both strains. However, the presence of LPG between LT-P and IVD-P EVs was different. Groups of mice immunized with EVs emulsified in the adjuvant and challenged with IVD-P parasites showed decreased lesion size and parasitic load compared with the nonimmunized groups. The immunization regimen with two doses showed high IFN-γ and IgG2a titers in challenged mice with either IVD-P or LT-P EVs. IL-4 and IL-10 were detected in immunized mice, suggesting a mixed Th1/Th2 profile. EVs released by either IVD-P or LT-P induced a partial protective effect in an immunization model. Thus, our results uncover a potential protective role of EVs from L. amazonensis for cutaneous leishmaniasis. Moreover, long-term maintenance under in vitro conditions did not seem to affect EV release and their immunization properties in mice.
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Live attenuated vaccines, a favorable strategy to provide long-term immunity against protozoan diseases. Trends Parasitol 2021; 38:316-334. [PMID: 34896016 DOI: 10.1016/j.pt.2021.11.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 11/12/2021] [Accepted: 11/12/2021] [Indexed: 12/25/2022]
Abstract
The control of diseases caused by protozoan parasites is one of the United Nations' Sustainable Development Goals. In recent years much research effort has gone into developing a new generation of live attenuated vaccines (LAVs) against malaria, Chagas disease and leishmaniasis. However, there is a bottleneck related to their biosafety, production, and distribution that slows downs further development. The success of irradiated or genetically attenuated sporozoites against malaria, added to the first LAV against leishmaniasis to be evaluated in clinical trials, is indicative that the drawbacks of LAVs are gradually being overcome. However, whether persistence of LAVs is a prerequisite for sustained long-term immunity remains to be clarified, and the procedures necessary for clinical evaluation of vaccine candidates need to be standardized.
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Volpedo G, Huston RH, Holcomb EA, Pacheco-Fernandez T, Gannavaram S, Bhattacharya P, Nakhasi HL, Satoskar AR. From infection to vaccination: reviewing the global burden, history of vaccine development, and recurring challenges in global leishmaniasis protection. Expert Rev Vaccines 2021; 20:1431-1446. [PMID: 34511000 DOI: 10.1080/14760584.2021.1969231] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Leishmaniasis is a major public health problem and the second most lethal parasitic disease in the world due to the lack of effective treatments and vaccines. Even when not lethal, leishmaniasis significantly affects individuals and communities through life-long disabilities, psycho-sociological trauma, poverty, and gender disparity in treatment. AREAS COVERED This review discusses the most relevant and recent research available on Pubmed and GoogleScholar highlighting leishmaniasis' global impact, pathogenesis, treatment options, and lack of effective control strategies. An effective vaccine is necessary to prevent morbidity and mortality, lower health care costs, and reduce the economic burden of leishmaniasis for endemic low- and middle-income countries. Since there are several forms of leishmaniasis, a pan-Leishmania vaccine without geographical restrictions is needed. This review also focuses on recent advances and common challenges in developing prophylactic strategies against leishmaniasis. EXPERT OPINION Despite advances in pre-clinical vaccine research, approval of a human leishmaniasis vaccine still faces major challenges - including manufacturing of candidate vaccines under Good Manufacturing Practices, developing well-designed clinical trials suitable in endemic countries, and defined correlates of protection. In addition, there is a need to explore Challenge Human Infection Model to avoid large trials because of fluctuating incidence and prevalence of leishmanasis.
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Affiliation(s)
- Greta Volpedo
- Departments of Pathology and Microbiology, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Ryan H Huston
- Departments of Pathology and Microbiology, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Erin A Holcomb
- Departments of Pathology and Microbiology, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Thalia Pacheco-Fernandez
- Departments of Pathology and Microbiology, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Sreenivas Gannavaram
- Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA
| | - Parna Bhattacharya
- Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA
| | - Hira L Nakhasi
- Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA
| | - Abhay R Satoskar
- Departments of Pathology and Microbiology, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
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Pandey SC, Pande V, Samant M. DDX3 DEAD-box RNA helicase (Hel67) gene disruption impairs infectivity of Leishmania donovani and induces protective immunity against visceral leishmaniasis. Sci Rep 2020; 10:18218. [PMID: 33106577 PMCID: PMC7589518 DOI: 10.1038/s41598-020-75420-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 09/30/2020] [Indexed: 11/10/2022] Open
Abstract
Visceral leishmaniasis (VL) is a vector-borne disease caused by the digenetic protozoan parasite Leishmania donovani complex. So far there is no effective vaccine available against VL. The DDX3 DEAD-box RNA Helicase (Hel67) is 67 kDa protein which is quite essential for RNA metabolism, amastigote differentiation, and infectivity in L. major and L. infantum. To investigate the role of Hel67 in the L. donovani, we created L. donovani deficient in the Hel67. Helicase67 null mutants (LdHel67-/-) were not able to differentiate as axenic amastigotes and were unable to infect the hamster. So, we have analyzed the prophylactic efficacy of the LdHel67-/- null mutant in hamsters. The LdHel67-/- null mutant based candidate vaccine exhibited immunogenic response and a higher degree of protection against L. donovani in comparison to the infected control group. Further, the candidate vaccine displayed antigen-specific delayed-type hypersensitivity (DTH) as well as strong antibody response and NO production which strongly correlates to long term protection of candidate vaccine against the infection. This study confirms the potential of LdHel67-/- null mutant as a safe and protective live attenuated vaccine candidate against visceral leishmaniasis.
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Affiliation(s)
- Satish Chandra Pandey
- Cell and Molecular Biology Laboratory, Department of Zoology, Kumaun University, SSJ Campus, Almora, Uttarakhand, India.,Department of Biotechnology, Kumaun University, Bhimtal Campus, Nainital, Uttarakhand, India
| | - Veena Pande
- Department of Biotechnology, Kumaun University, Bhimtal Campus, Nainital, Uttarakhand, India
| | - Mukesh Samant
- Cell and Molecular Biology Laboratory, Department of Zoology, Kumaun University, SSJ Campus, Almora, Uttarakhand, India.
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