scholarly journals Immunity to Visceral Leishmaniasis Using Genetically Defined Live-Attenuated Parasites

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Angamuthu Selvapandiyan ◽  
Ranadhir Dey ◽  
Sreenivas Gannavaram ◽  
Ines Lakhal-Naouar ◽  
Robert Duncan ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Visceral Leishmaniasis ◽  
Leishmania Donovani ◽  
Natural Infection ◽  
Parasitic Disease ◽  
Self Healing ◽  
Vaccine Candidates ◽  
Mucocutaneous Leishmaniasis ◽  
The World ◽  
Drug Treatments

Leishmaniasis is a protozoan parasitic disease endemic to the tropical and subtropical regions of the world, with three major clinical forms, self-healing cutaneous leishmaniasis (CL), mucocutaneous leishmaniasis (MCL), and visceral leishmaniasis (VL). Drug treatments are expensive and often result in the development of drug resistance. No vaccine is available against leishmaniasis. SubunitLeishmaniavaccine immunization in animal models has shown some efficacy but little or none in humans. However, individuals who recover from natural infection are protected from reinfection and develop life-long protection, suggesting that infection may be a prerequisite for immunological memory. Thus, genetically altered live-attenuated parasites with controlled infectivity could achieve such memory. In this paper, we discuss development and characteristics of genetically altered, live-attenuatedLeishmania donovaniparasites and their possible use as vaccine candidates against VL. In addition, we discuss the challenges and other considerations in the use of live-attenuated parasites.

scholarly journals Genomic and phenotypic characterization of experimentally selected resistant Leishmania donovani reveals a role for dynamin-1 like protein in the mechanism of resistance to a novel anti-leishmanial compound

2021 ◽  
Author(s):  
Aya Hefnawy ◽  
Gabriel Negreira ◽  
Marlene Jara ◽  
James A. Cotton ◽  
Ilse Maes ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Visceral Leishmaniasis ◽  
Infectious Diseases ◽  
Leishmania Donovani ◽  
Neglected Tropical Diseases ◽  
Arms Race ◽  
Etiological Agent ◽  
Phenotypic Characterization ◽  
Tropical Diseases

AbstractThe implementation of prospective drug resistance (DR) studies in the R&D pipelines is a common practice for many infectious diseases, but not for Neglected Tropical Diseases. Here, we explored and demonstrated the importance of this approach, using as paradigms Leishmania donovani, the etiological agent of Visceral Leishmaniasis (VL), and TCMDC-143345, a promising compound of the GSK ‘Leishbox’ to treat VL. We experimentally selected resistance to TCMDC-143345 in vitro and characterized resistant parasites at genomic and phenotypic levels. We found that it took more time to develop resistance to TCMDC-143345 than to other drugs in clinical use and that there was no cross resistance to these drugs, suggesting a new and unique mechanism. By whole genome sequencing, we found two mutations in the gene encoding the L. donovani dynamin-1-like protein (LdoDLP1) that were fixed at highest drug pressure. Through phylogenetic analysis, we identified LdoDLP1 as a family member of the dynamin-related proteins, a group of proteins that impacts the shapes of biological membranes by mediating fusion and fission events, with a putative role in mitochondrial fission. We found that L. donovani lines genetically engineered to harbor the two identified LdoDLP1 mutations were resistant to TCMDC-143345 and displayed altered mitochondrial properties. By homology modeling, we showed how the two LdoDLP1 mutations may influence protein structure and function. Taken together, our data reveal a clear involvement of LdoDLP1 in the adaptation/resistance of L. donovani to TCMDC-143345.ImportanceHumans and their pathogens are continuously locked in a molecular arms race during which the eventual emergence of pathogen drug resistance (DR) seems inevitable. For neglected tropical diseases (NTDs), DR is generally studied retrospectively, once it has already been established in clinical settings. We previously recommended to keep one step ahead in the host-pathogen arms race and implement prospective DR studies in the R&D pipeline, a common practice for many infectious diseases, but not for NTDs. Here, using Leishmania donovani, the etiological agent of Visceral Leishmaniasis (VL), and TCMDC-143345, a promising compound of the GSK ‘Leishbox’ to treat VL, as paradigms, we experimentally selected resistance to the compound and proceeded to genomic and phenotypic characterization of DR parasites. The results gathered in the present study suggest a new DR mechanism involving the L. donovani dynamin-1 like protein (LdoDLP1) and demonstrate the practical relevance of prospective DR studies.

scholarly journals Use of an Attenuated Leishmanial Parasite as an Immunoprophylactic and Immunotherapeutic Agent against Murine Visceral Leishmaniasis

2000 ◽  
Vol 7 (2) ◽  
pp. 233-240 ◽  
Author(s):  
Srirupa Mukhopadhyay ◽  
Sandip Bhattacharyya ◽  
Ramdhan Majhi ◽  
Tripti De ◽  
Khudiram Naskar ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Elevated Level ◽  
Leishmania Donovani ◽  
Peritoneal Macrophages ◽  
Delayed Type Hypersensitivity ◽  
Self Healing ◽  
Immunotherapeutic Agent ◽  
Virulent Challenge ◽  
Visceral Infection

ABSTRACT The ability of the leishmanial parasite UR6 to act as an immunoprophylactic and immunotherapeutic agent against Leishmania donovani infection in BALB/c mice was investigated. Unlike the virulent L. donovani AG83 (MOHOM/IN/1983/AG83), UR6 given through intracardiac route failed to induce visceral infection, but when it was injected subcutaneously, UR6 induced a short-lived and localized self-healing skin lesion. Priming of peritoneal macrophages with UR6 in vitro induced superoxide (O2 −) generation, whereas similar experiments with virulent AG83 inhibited O2 − generation. It was observed that priming of mice with either live or sonicated UR6 in the absence of any adjuvant provided strong protection against subsequent virulent challenge. Further, UR6-primed infected mice not only displayed a strong antileishmanial delayed-type hypersensitivity (DTH) response but also showed an elevated level of the serum antileishmanial immunoglobulin G2a (IgG2a) isotype, whereas infected mice failed to mount any antileishmanial DTH response and showed an elevated level of IgG1. This indicates that UR6 priming and subsequent L. donovani infection allowed the expansion of Th1 cells. Our studies indicate that UR6 has potential to be used as an immunoprophylactic and immunotherapeutic agent against experimental visceral leishmaniasis.

scholarly journals A T-Cell Epitope-Based Multi-Epitope Vaccine Designed Using Human HLA Specific T Cell Epitopes Induces a Near-Sterile Immunity against Experimental Visceral Leishmaniasis in Hamsters

Vaccines ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1058
Author(s):  
Aryandra Arya ◽  
Sunil K. Arora
Keyword(s):  
T Cell ◽  
Visceral Leishmaniasis ◽  
Leishmania Donovani ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Cell Epitope ◽  
Effective Vaccine ◽  
T Cell Epitope ◽  
Hamster Model ◽  
Vaccine Candidates

Visceral leishmaniasis is a neglected tropical disease affecting 12 million people annually. Even in the second decade of the 21st century, it has remained without an effective vaccine for human use. In the current study, we designed three multiepitope vaccine candidates by the selection of multiple IFN-γ inducing MHC-I and MHC-II binder T-cell specific epitopes from three previously identified antigen genes of Leishmania donovani from our lab by an immuno-informatic approach using IFNepitope, the Immune Epitope Database (IEDB) T cell epitope identification tools, NET-MHC-1, and NET MHC-2 webservers. We tested the protective potential of these three multiepitope proteins as a vaccine in a hamster model of visceral leishmaniasis. The immunization data revealed that the vaccine candidates induced a very high level of Th1 biased protective immune response in-vivo in a hamster model of experimental visceral leishmaniasis, with one of the candidates inducing a near-sterile immunity. The vaccinated animals displayed highly activated monocyte macrophages with the capability of clearing intracellular parasites due to increased respiratory burst. Additionally, these proteins induced activation of polyfunctional T cells secreting INF-γ, TNF-α, and IL-2 in an ex-vivo stimulation of human peripheral blood mononuclear cells, further supporting the protective nature of the designed candidates.

scholarly journals Evolutionary genomics of epidemic visceral leishmaniasis in the Indian subcontinent

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Hideo Imamura ◽  
Tim Downing ◽  
Frederik Van den Broeck ◽  
Mandy J Sanders ◽  
Suman Rijal ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Leishmania Donovani ◽  
Indian Subcontinent ◽  
Evolutionary Genomics ◽  
Whole Genome ◽  
Parasitic Disease ◽  
Distinct Population ◽  
Genome Sequences ◽  
Vector Borne ◽  
Base Pair Insertion

Leishmania donovani causes visceral leishmaniasis (VL), the second most deadly vector-borne parasitic disease. A recent epidemic in the Indian subcontinent (ISC) caused up to 80% of global VL and over 30,000 deaths per year. Resistance against antimonial drugs has probably been a contributing factor in the persistence of this epidemic. Here we use whole genome sequences from 204 clinical isolates to track the evolution and epidemiology of L. donovani from the ISC. We identify independent radiations that have emerged since a bottleneck coincident with 1960s DDT spraying campaigns. A genetically distinct population frequently resistant to antimonials has a two base-pair insertion in the aquaglyceroporin gene LdAQP1 that prevents the transport of trivalent antimonials. We find evidence of genetic exchange between ISC populations, and show that the mutation in LdAQP1 has spread by recombination. Our results reveal the complexity of L. donovani evolution in the ISC in response to drug treatment.

scholarly journals A T-Cell Epitope-Based Multi-Epitope Vaccine Designed Using Human HLA Specific T Cell Epitopes Induces Sterile Immunity against Experimental Visceral Leishmaniasis in Hamsters

2021 ◽  
Author(s):  
Aryandra Arya ◽  
Sunil K Arora
Keyword(s):  
T Cell ◽  
Visceral Leishmaniasis ◽  
Leishmania Donovani ◽  
Mononuclear Cells ◽  
Ex Vivo ◽  
Human Peripheral Blood ◽  
Cell Epitope ◽  
Effective Vaccine ◽  
Hamster Model ◽  
Vaccine Candidates

Visceral Leishmaniasis is a neglected tropical disease affecting 12 million people annually. Even in the second decade of the 21st century, it has remained without an effective vaccine for human use. In the current study, we have designed three multiepitope vaccine candidates by the selection of multiple IFN-γ inducing MHC-I and MHC-II binder T-cell specific epitopes from 3 previously identified antigen genes of Leishmania donovani from our lab, by immune-informatic approach using IFNepiotpe, NET-MHC-1 and NET MHC-2 webservers. We have tested the protective potential of these three multiepitope proteins as vaccine in a hamster model of visceral leishmaniasis. The immunization data revealed that the vaccine candidates induced a very high level of Th-1 biased protective immune response in-vivo in a hamster model of experimental visceral Leishmaniasis, with one of the candidates inducing a sterile immunity. The vaccinated animals displayed highly activated monocyte macrophages with the capability of clearing intracellular parasites due to increased respiratory burst. Additionally, these proteins induced activation of polyfunctional T cells secreting INF-γ, TNF-α, and IL-2 in ex-vivo stimulation of human peripheral blood mononuclear cells, further supporting the protective nature of designed candidates.

scholarly journals Identification of Vaccine Candidates for Experimental Visceral Leishmaniasis by Immunization with Sequential Fractions of a cDNA Expression Library

2000 ◽  
Vol 68 (10) ◽  
pp. 5595-5602 ◽  
Author(s):  
Peter C. Melby ◽  
Gary B. Ogden ◽  
Hector A. Flores ◽  
Weiguo Zhao ◽  
Christopher Geldmacher ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Cdna Library ◽  
Leishmania Donovani ◽  
Parasite Burden ◽  
Public Health Problem ◽  
Cdna Expression Library ◽  
Sequential Fractionation ◽  
Expression Library ◽  
Vaccine Candidates

ABSTRACT Visceral leishmaniasis caused by the intracellular parasiteLeishmania donovani is a significant public health problem in many regions of the world. Because of its large genome and complex biology, developing a vaccine for this pathogen has proved to be a challenging task and, to date, protective recombinant vaccine candidates have not been identified. To tackle this difficult problem, we adopted a reductionist approach with the intention of identifying cDNA sequences in an L. donovani amastigote cDNA library that collectively or singly conferred protection against parasite challenge in a murine model of visceral leishmaniasis. We immunized BALB/c mice with plasmid DNA isolated and pooled from 15 cDNA sublibraries (∼2,000 cDNAs/sublibrary). Following systemic challenge with L. donovani, mice immunized with 6 of these 15 sublibraries showed a significantly reduced (35- to 1,000-fold) hepatic parasite burden. Because of the complexity and magnitude of the sequential fractionation-immunization-challenge approach, we restricted our attention to the two sublibraries that conferred the greatest in vivo protection. From one of these two sublibraries, we identified several groups of cDNAs that afforded protection, including a set of nine novel cDNAs and, surprisingly, a group of five cDNAs that encoded L. donovani histone proteins. At each fractionation step, the cDNA sublibraries or the smaller DNA fractions that afforded in vivo protection against the parasite also induced in vitro parasite-specific T helper 1 immune responses. Our studies demonstrate that immunization with sequential fractions of a cDNA library is a powerful strategy for identifying anti-infective vaccine candidates.

scholarly journals Dissecting pathways to thrombocytopenia in a mouse model of visceral leishmaniasis

2021 ◽  
Vol 5 (6) ◽  
pp. 1627-1637
Author(s):  
Gulab Fatima Rani ◽  
Olivier Preham ◽  
Helen Ashwin ◽  
Najmeeyah Brown ◽  
Ian S. Hitchcock ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Leishmania Donovani ◽  
Granulomatous Inflammation ◽  
Parasite Load ◽  
Immune Dysregulation ◽  
Experimental Models ◽  
Severe Thrombocytopenia ◽  
Parasitic Disease ◽  
Residual Damage ◽  
Cytoplasmic Maturation

Abstract Visceral leishmaniasis is an important yet neglected parasitic disease caused by infection with Leishmania donovani or L infantum. Disease manifestations include fever, weight loss, hepatosplenomegaly, immune dysregulation, and extensive hematological complications. Thrombocytopenia is a dominant hematological feature seen in both humans and experimental models, but the mechanisms behind this infection-driven thrombocytopenia remain poorly understood. Using a murine model of experimental visceral leishmaniasis (EVL), we demonstrated a progressive decrease in platelets from day 14 after infection, culminating in severe thrombocytopenia by day 28. Plasma thrombopoietin (TPO) levels were reduced in infected mice, at least in part because of the alterations in the liver microenvironment associated with granulomatous inflammation. Bone marrow (BM) megakaryocyte cytoplasmic maturation was significantly reduced. In addition to a production deficit, we identified significant increases in platelet clearance. L donovani–infected splenectomized mice were protected from thrombocytopenia compared with sham operated infected mice and had a greater response to exogenous TPO. Furthermore, infection led to higher levels of platelet opsonization and desialylation, both associated with platelet clearance in spleen and liver, respectively. Critically, these changes could be reversed rapidly by drug treatment to reduce parasite load or by administration of TPO agonists. In summary, our findings demonstrate that the mechanisms underpinning thrombocytopenia in EVL are multifactorial and reversible, with no obvious residual damage to the BM microenvironment.

Genotypic Methods for HIV Drug Resistance Monitoring: The Opportunities and Challenges Faced by China

2019 ◽  
Vol 17 (4) ◽  
pp. 225-239 ◽  
Author(s):  
Lulu Zuo ◽  
Ke Peng ◽  
Yihong Hu ◽  
Qinggang Xu
Keyword(s):  
Drug Resistance ◽  
Virological Suppression ◽  
Testing Methods ◽  
Hiv Drug Resistance ◽  
Advantages And Disadvantages ◽  
Hiv Epidemic ◽  
Routine Surveillance ◽  
The World ◽  
Global Project ◽  
Hiv 1

AIDS is a globalized infectious disease. In 2014, UNAIDS launched a global project of “90-90-90” to end the HIV epidemic by 2030. The second and third 90 require 90% of HIV-1 infected individuals receiving antiretroviral therapy (ART) and durable virological suppression. However, wide use of ART will greatly increase the emergence and spreading of HIV drug resistance and current HIV drug resistance test (DRT) assays in China are seriously lagging behind, hindering to achieve virological suppression. Therefore, recommending an appropriate HIV DRT method is critical for HIV routine surveillance and prevention in China. In this review, we summarized the current existing HIV drug resistance genotypic testing methods around the world and discussed the advantages and disadvantages of these methods.

Sign in / Sign up

Export Citation Format

Share Document