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Sample records for experimental leishmania donovani-induced

  1. Dynamic imaging of experimental Leishmania donovani-induced hepatic granulomas detects Kupffer cell-restricted antigen presentation to antigen-specific CD8 T cells.

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    Lynette Beattie

    2010-03-01

    Full Text Available Kupffer cells (KCs represent the major phagocytic population within the liver and provide an intracellular niche for the survival of a number of important human pathogens. Although KCs have been extensively studied in vitro, little is known of their in vivo response to infection and their capacity to directly interact with antigen-specific CD8(+ T cells. Here, using a combination of approaches including whole mount and thin section confocal microscopy, adoptive cell transfer and intra-vital 2-photon microscopy, we demonstrate that KCs represent the only detectable population of mononuclear phagocytes within granulomas induced by Leishmania donovani infection that are capable of presenting parasite-derived peptide to effector CD8(+ T cells. This restriction of antigen presentation to KCs within the Leishmania granuloma has important implications for the identification of new candidate vaccine antigens and for the design of novel immuno-therapeutic interventions.

  2. Intracellular replication-deficient Leishmania donovani induces long lasting protective immunity against visceral leishmaniasis.

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    Selvapandiyan, Angamuthu; Dey, Ranadhir; Nylen, Susanne; Duncan, Robert; Sacks, David; Nakhasi, Hira L

    2009-08-01

    No vaccine is currently available for visceral leishmaniasis (VL) caused by Leishmania donovani. This study addresses whether a live attenuated centrin gene-deleted L. donovani (LdCen1(-/-)) parasite can persist and be both safe and protective in animals. LdCen1(-/-) has a defect in amastigote replication both in vitro and ex vivo in human macrophages. Safety was shown by the lack of parasites in spleen and liver in susceptible BALB/c mice, immune compromised SCID mice, and human VL model hamsters 10 wk after infection. Mice immunized with LdCen1(-/-) showed early clearance of virulent parasite challenge not seen in mice immunized with heat killed parasites. Upon virulent challenge, the immunized mice displayed in the CD4(+) T cell population a significant increase of single and multiple cytokine (IFN-gamma, IL-2, and TNF) producing cells and IFN-gamma/IL10 ratio. Immunized mice also showed increased IgG2a immunoglobulins and NO production in macrophages. These features indicated a protective Th1-type immune response. The Th1 response correlated with a significantly reduced parasite burden in the spleen and no parasites in the liver compared with naive mice 10 wk post challenge. Protection was observed, when challenged even after 16 wk post immunization, signifying a sustained immunity. Protection by immunization with attenuated parasites was also seen in hamsters. Immunization with LdCen1(-/-) also cross-protected mice against infection with L. braziliensis that causes mucocutaneous leishmaniasis. Results indicate that LdCen1(-/-) can be a safe and effective vaccine candidate against VL as well as mucocutaneous leishmaniasis causing parasites.

  3. Genetically Engineered Ascorbic acid-deficient Live Mutants of Leishmania donovani induce long lasting Protective Immunity against Visceral Leishmaniasis.

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    Anand, Sneha; Madhubala, Rentala

    2015-06-02

    Visceral leishmaniasis caused by Leishmania donovani is the most severe systemic form of the disease. There are still no vaccines available for humans and there are limitations associated with the current therapeutic regimens for leishmaniasis. Recently, we reported functional importance of Arabino-1, 4-lactone oxidase (ALO) enzyme from L. donovani involved in ascorbate biosynthesis pathway. In this study, we have shown that ΔALO parasites do not affect the ability of null mutants to invade visceral organs but severely impair parasite persistence beyond 16 week in BALB/c mice and hence are safe as an immunogen. Both short term (5 week) and long term (20 week) immunization with ΔALO parasites conferred sustained protection against virulent challenge in BALB/c mice, activated splenocytes and resulted in induction of pro-inflammatory cytokine response. Protection in immunized mice after challenge correlated with the stimulation of IFN-γ producing CD4(+) and CD8(+) T cells. Antigen-mediated cell immunity correlated with robust nitrite and superoxide generation, macrophage-derived oxidants critical in controlling Leishmania infection. Our data shows that live attenuated ΔALO parasites are safe, induce protective immunity and can provide sustained protection against Leishmania donovani. We further conclude that the parasites attenuated in their anti-oxidative defence mechanism can be exploited as vaccine candidates.

  4. Experimental treatment with sodium stibogluconate of hamsters infected with Leishmania (Leishmania) chagasi and Leishmania (Leishmania) amazonensis

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    Elizabeth M. de Figueiredo; Silva,Jaime Costa e; Brazil,Reginaldo P

    1999-01-01

    The present paper reports the experimental treatment of hamsters infected with Leishmania chagasi and Leishmania amazonensis with sodium stibogluconate (20mg/kg/day x 20 days). Only with L. chagasi did the treatment result in the complete elimination of parasites from the spleen. However, no parasitological cure was achieved in hamsters infected with L. amazonensis.O presente trabalho é um relato do tratamento experimental de hamsters infectado com Leishmania chagasi e Leishmania amazonensis ...

  5. Efficacy, Safety and Cost-Effectiveness of Thermotherapy in the Treatment of Leishmania donovani-Induced Cutaneous Leishmaniasis: A Randomized Controlled Clinical Trial.

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    Refai, Wardha F; Madarasingha, Nayani P; Sumanasena, Buthsiri; Weerasingha, Sudath; De Silva, Amala; Fernandopulle, Rohini; Satoskar, Abhay R; Karunaweera, Nadira D

    2017-10-01

    Leishmania donovani causes cutaneous leishmaniasis (CL) in Sri Lanka. Standard treatment is multiple, painful doses of intralesional sodium stibogluconate (IL-SSG). Treatment failures are increasingly reported, hence the need to investigate alternatives. Efficacy, safety, and cost-effectiveness of thermotherapy were assessed for the first time for L. donovani CL. A single blinded noninferiority randomized controlled trial was conducted on new laboratory-confirmed CL patients with single lesions (N = 213). Selected patients were randomly assigned to 1) test group (N = 98; single session of radiofrequency-induced heat therapy (RFHT) given at 50°C for 30 seconds) and 2) control group (N = 115; 1-3 mL IL-SSG given weekly, until cure/10 doses). Patients were followed-up fortnightly for 12 weeks to assess clinical cure. Cost of treatment was assessed using scenario building technique. Cure rates by 8, 10, and 12 weeks in RFHT group were 46.5%, 56.5%, and 65.9% as opposed to 28%, 40.8%, and 59.4% in IL-SSG group, with no major adverse events. Cure rate by RFHT was significantly higher at 8 weeks (P = 0.009, odds ratio [OR]: 2.236, confidence interval [CI]: 1.217-4.108) and 10 weeks (P = 0.035, OR: 1.881, CI: 1.044-3.388), but comparable thereafter. Cost of RFHT was 7 times less (USD = 1.54/patient) than IL-SSG (USD = 11.09/patient). A single application of RFHT is safe, cost-effective, and convenient, compared with multiple doses of IL-SSG in the treatment of L. donovani CL. Therefore, RFHT would be considered noninferior as per trial outcome when compared with standard IL-SSG therapy with multiple benefits for the patient and the national health care system.

  6. Performance of commercially available serological diagnostic tests to detect Leishmania infantum infection on experimentally infected dogs.

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    Rodríguez-Cortés, Alhelí; Ojeda, Ana; Todolí, Felicitat; Alberola, Jordi

    2013-01-31

    Leishmania infantum (syn. Leishmania chagasi) is the etiological agent of a widespread serious zoonotic disease that affects both humans and dogs. Prevalence and incidence of the canine infection are important parameters to determine the risk and the ways to control this reemergent zoonosis. Unfortunately, there is not a gold standard test for Leishmania infection. Our aim was to assess the operative validity of commercial tests used to detect antibodies to Leishmania in serum samples from experimental infections. Three ELISA tests (LEISCAN(®) Leishmania ELISA Test, INGEZIM(®) LEISHMANIA, and INGEZIM(®) LEISHMANIA VET), three immunochromatographic tests (INGEZIM(®) LEISHMACROM, SNAP(®) Leishmania, and WITNESS(®) Leishmania), and one IFAT were evaluated. LEISCAN(®) Leishmania ELISA test achieved the highest sensitivity and accuracy (both 0.98). Specificity was 1 for all tests except for IFAT. All tests but IFAT obtained a positive predictive value of 1, while the maximum negative predictive value was achieved by LEISCAN(®) Leishmania ELISA Test (0.93). The best positive likelihood ratio was obtained by INGEZIM(®) LEISHMANIA VET (30.26), while the best negative likelihood ratio was obtained by LEISCAN(®) Leishmania ELISA Test (0.02). The highest diagnostic odds ratio was achieved by LEISCAN(®) Leishmania ELISA Test (729.00). The largest area under the ROC curve was obtained by LEISCAN(®) Leishmania ELISA Test (0.981). Quantitative ELISA based tests performmed better than qualitative tests ("Rapid Tests"), and the test best suited to detect Leishmania in infected dogs and to provide clinically useful information was LEISCAN(®) Leishmania ELISA Test. This and other results point also to the need of revising the status of IFAT as a gold standard for the diagnosis of leishmaniasis. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. In silico and in vitro comparative activity of novel experimental derivatives against Leishmania major and Leishmania infantum promastigotes.

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    Khademvatan, Shahram; Adibpour, Neda; Eskandari, Alborz; Rezaee, Saeed; Hashemitabar, Mahmoud; Rahim, Fakher

    2013-10-01

    This in silico and in vitro comparative study was designed to evaluate the effectiveness of some biurets (K1 to K8) and glucantime against Leishmania major and Leishmania infantum promastigotes. Overall, eight experimental ligands and glucantime were docked using AutoDock 4.3 program into the active sites of Leishmania major and Leishmania infantum pteridine reductase 1, which were modeled using homology modeling programs. The colorimetric MTT assay was used to find L. major and L. infantum promastigotes viability at different concentrations of biuret derivatives in a concentration and time-dependent manner and the obtained results were expressed as 50% and 90% of inhibitory concentration (IC₅₀ and IC₉₀). In silico method showed that out of eight experimental ligands, four compounds were more active on pteridine reductase 1. K3 was the most active against L. major promastigotes with an IC₅₀ of 6.8 μM and an IC₉₀ of 40.2 μM, whereas for L. infantum promastigotes was K8 with IC₅₀ of 7.8 μM. The phenylethyl derivative (K7) showed less toxicity (IC₅₀s>60 μM) in both Leishmania strains. Glucantime displayed less growth inhibition in concentration of about 20 μM. In silico and especially docking results in a recent study were in accordance with the in vitro activity of these compounds in presented study and compound K3, K2 and K8 showed reasonable levels of selectivity for the Leishmania pteridine reductase 1. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. A Non-pathogenic Recombinant Leishmania Expressing Lipophosphoglycan 3 Against Experimental Infection with Leishmania infantum.

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    Pirdel, L; Farajnia, S

    2017-07-01

    Visceral leishmaniasis (VL) is caused by Leishmania infantum in the Mediterranean basin and affects primarily children and immunosuppressed individuals. Various strategies of vaccination have so far been examined by either protein or DNA without achievable complete protection against the disease. The live non-pathogenic lizard parasite, Leishmania tarentolae, expressing elected Leishmania antigens has recently provided a promising new approach as a safe and effective live vaccine candidate to prevent leishmaniasis. Here, we evaluated the immunoprotective potential of a live recombinant L. tarentolae expressing Lipophosphoglycan 3 (LPG3) antigen against L. infantum infection in BALB/c mice. Results indicated that the administration of live recombinant Leishmania produced a significant high level of IFN-γ accompanied by reduced levels of IL-10 as compared to wild-type parasites as live vaccine control, thus suggesting the induction of a Th1-type immune response in a mouse model of visceral leishmaniasis. Analysis of the IgG antibody response also showed high levels of IgG2a relative to IgG1 in sera of mice immunized with recombinant Leishmania parasites. However, immune responses elicited by this live vaccine conferred partial protection against infectious challenge. Therefore, further studies are required to increase its protective efficacy. © 2017 The Foundation for the Scandinavian Journal of Immunology.

  9. Action of pentoxifylline on experimental cutaneous leishmaniasis due to Leishmania (Leishmania amazonensis

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    Oliveira Thiago de Sá

    2000-01-01

    Full Text Available In the animal model of leishmaniasis caused by Leishmania (Leishmania amazonensis there is a complex mechanism of the host-parasite interaction. The present study was performed to interfere with the inflammatory reaction to the parasites, through immune modulation. Female C5BL/6 isogenic mice were used, some of which were inoculated on the right ear and others on the right footpad with 3.10(6 stationary phase promastigotes of the MHOM/BR/PH8 strain of L. (L. amazonensis, and were allocated in three groups: the first received pentoxifylline 8mg/kg every 12 h, since the first day; the second one received the same dose since the 40th day of infection and a control group that did not receive any treatment. All the ears excised were analyzed to determine the variation in weight between both ears and for histopathological analyses. A quantification of the parasites was done using the limiting dilution assay. A significant reduction of the number of parasites, was observed among the animals treated which had an accordingly significant reduction on the weight of the ears. Pentoxifylline reduced the macrophages propensity to vacuolation and induced a more effective destruction of the parasites by these cells. Moreover, the group that began the treatment later did not show the same effectiveness.

  10. An experimental protocol for the establishment of dogs with long-term cellular immune reactions to Leishmania antigens

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    Márcia Cristina Aquino Teixeira

    2011-03-01

    Full Text Available Domestic dogs are considered to be the main reservoirs of zoonotic visceral leishmaniasis. In this work, we evaluated a protocol to induce Leishmania infantum/Leishmania chagasi-specific cellular and humoral immune responses in dogs, which consisted of two injections of Leishmania promastigote lysate followed by a subcutaneous inoculation of viable promastigotes. The primary objective was to establish a canine experimental model to provide positive controls for testing immune responses to Leishmania in laboratory conditions. After inoculation of viable promastigotes, specific proliferative responses of peripheral blood mononuclear cells (PBMCs to either Leishmania lysate or recombinant proteins, the in vitro production of interferon-γ by antigen-stimulated PBMCs and a significant increase in circulating levels of anti-Leishmania antibodies were observed. The immunized dogs also displayed positive delayed-type hypersensitivity reactions to Leishmania crude antigens and to purified recombinant proteins. An important finding that supports the suitability of the dogs as positive controls is that they remained healthy for the entire observation period, i.e., more than seven years after infection. Following the Leishmania antigen lysate injections, the infection of dogs by the subcutaneous route appears to induce a sustained cellular immune response, leading to an asymptomatic infection. This provides a useful model for both the selection of immunogenic Leishmania antigens and for immunobiological studies on their possible immunoprotective activities.

  11. Antimony Resistance in Leishmania, Focusing on Experimental Research

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    Fakhri Jeddi

    2011-01-01

    Full Text Available Leishmaniases are parasitic diseases that spread in many countries with a prevalence of 12 million cases. There are few available treatments and antimonials are still of major importance in the therapeutic strategies used in most endemic regions. However, resistance toward these compounds has recently emerged in areas where the replacement of these drugs is mainly limited by the cost of alternative molecules. In this paper, we reviewed the studies carried out on antimonial resistance in Leishmania. Several common limitations of these works are presented before prevalent approaches to evidence antimonial resistance are related. Afterwards, phenotypic determination of resistance is described, then confronted to clinical outcome. Finally, we detail molecular mechanisms and targets involved in resistance and already identified in vitro within selected mutant strains or in clinical isolates.

  12. Therapeutic trial in experimental tegumentary leishmaniasis caused by Leishmania (Leishmania amazonensis. A comparative study between mefloquine and aminosidine Ensaio terapêutico na leishmaniose tegumentar experimental causada por Leishmania (Leishmania amazonensis. Um estudo comparativo entre mefloquina e aminosidine

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    Letícia Oba Galvão

    2000-08-01

    Full Text Available One hundred and eighty-two male inbred C57/BL/6 mice were infected with 3 x 106 Leishmania (Leishmania amazonensis promastigotes of the MHOM/BR/PH8 strain by means of a subcutaneous injection in the right ear. The animals were separated in three groups: 1 oral mefloquine hydrochloride treatment (16mg/kg/day/10 days, 2 intramuscular aminosidine (Paromomycin® treatment (20mg/kg/20 days and 3 control. Twenty six mice of each treated group were sacrificed, one at the end of treatment (nine weeks after inoculation, and one six weeks later (fifteen weeks after inoculation. Control Group animals were sacrificed at weeks six, nine and fifteen after inoculation. There was no significant difference between Group 1 (mefloquine and Group 3 (control subjects. Group 2 animals (aminosidine presented the smallest differences of all, both at the end of the treatment and six weeks later. The histopato-logical parameters have shown the following findings: a there was no significant difference between the mefloquine treated group and the control group; the group treated with aminosidine showed fewer of vacuolated macrophages than the control group, at week 9 (end of treatment. b both at the end of treatment and six weeks later, evaluation of tissue necrosis and tissue fibrosis revealed no differences between the treated groups. It was found that six weeks after the end of treatment, mice in the control group presented significantly more severe degrees of fibrosis than mice in the other groups. It can be concluded that mefloquine showed limited therapeutic effect in this experimental model, whereas aminosidine had a significant effect. Nevertheless, neither of them resulted in cure of the lesions.Foram utilizados 182 camundongos machos, isogênicos, da linhagem C57BL/6 inoculados na orelha direita com 3,0 x 10(6 formas promastigotas da cepa MHOM/BR/PH8 de Leishmania (Leishmania amazonensis. Os animais foram separados em três grupos: 1 52 animais tratados com

  13. Comparative evaluation of two vaccine candidates against experimental leishmaniasis due to Leishmania major infection in four inbred mouse strains.

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    Benhnini, Fouad; Chenik, Mehdi; Laouini, Dhafer; Louzir, Hechmi; Cazenave, Pierre André; Dellagi, Koussay

    2009-11-01

    Experimental leishmaniasis in BALB/c and C57BL/6 mice are the most investigated murine models that were used for the preclinical evaluation of Leishmania vaccine candidates. We have previously described two new inbred mouse strains named PWK and MAI issued from feral founders that also support the development of experimental leishmaniasis due to L. major. In this study, we sought to determine whether different mouse inbred strains generate concordant or discordant results when used to evaluate the potential of Leishmania proteins to protect against experimental leishmaniasis. To this end, two Leishmania proteins, namely, LACK (for Leishmania homolog of receptor for activated C kinase) and LmPDI (for L. major protein disulfide isomerase) were compared for their capacity to protect against experimental leishmaniasis in PWK, MAI, BALB/c, and C57BL/6 inbred mouse strains. Our data show that the capacity of Leishmania proteins to confer protection depends on the mouse strain used, stressing the important role played by the genetic background in shaping the immune response against the pathogen. These results may have important implications for the preclinical evaluation of candidate Leishmania vaccines: rather than using a single mouse strain, a panel of different inbred strains of various genetic backgrounds should be tested in parallel. The antigen that confers protection in the larger range of inbred strains may have better chances to be also protective in outbred human populations and should be selected for clinical trials.

  14. Comparative Evaluation of Two Vaccine Candidates against Experimental Leishmaniasis Due to Leishmania major Infection in Four Inbred Mouse Strains▿

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    Benhnini, Fouad; Chenik, Mehdi; Laouini, Dhafer; Louzir, Hechmi; Cazenave, Pierre André; Dellagi, Koussay

    2009-01-01

    Experimental leishmaniasis in BALB/c and C57BL/6 mice are the most investigated murine models that were used for the preclinical evaluation of Leishmania vaccine candidates. We have previously described two new inbred mouse strains named PWK and MAI issued from feral founders that also support the development of experimental leishmaniasis due to L. major. In this study, we sought to determine whether different mouse inbred strains generate concordant or discordant results when used to evaluate the potential of Leishmania proteins to protect against experimental leishmaniasis. To this end, two Leishmania proteins, namely, LACK (for Leishmania homolog of receptor for activated C kinase) and LmPDI (for L. major protein disulfide isomerase) were compared for their capacity to protect against experimental leishmaniasis in PWK, MAI, BALB/c, and C57BL/6 inbred mouse strains. Our data show that the capacity of Leishmania proteins to confer protection depends on the mouse strain used, stressing the important role played by the genetic background in shaping the immune response against the pathogen. These results may have important implications for the preclinical evaluation of candidate Leishmania vaccines: rather than using a single mouse strain, a panel of different inbred strains of various genetic backgrounds should be tested in parallel. The antigen that confers protection in the larger range of inbred strains may have better chances to be also protective in outbred human populations and should be selected for clinical trials. PMID:19726616

  15. Detailed analysis of an experimental challenge model for Leishmania infantum (JPC strain) in dogs.

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    Poot, Jacqueline; Rogers, Matthew E; Bates, Paul A; Vermeulen, Arno

    2005-06-10

    In this study, disease progression after intravenous or subdermal infection of dogs with Leishmania infantum JPC strain was monitored. A challenge performed on 14 dogs via the intravenous route with 5 x 10(7) stationary phase promastigotes of the L. infantum JPC strain was 100% successful. During a follow up period of 1.5 years, several parameters were evaluated in order to find the most reliable disease markers. Parasite detection by culture and histology were found to be very sensitive (100%). Additionally, regular physical examination, serology and serum gamma-globulin levels were found to be useful parameters in the evaluation of disease severity and are recommended for inclusion in vaccination-challenge experiments. Although this intravenous challenge model has practical limitations, the data set confirms it is the best experimental model currently available for vaccine development. Two intravenously infected dogs were treated with corticosteroids for 5 months. This treatment was shown to enhance all aspects of a Leishmania infection. Five more dogs were infected by sub-dermal injection of promastigotes mixed with a proteophosphoglycan-matrix (PSG) secreted by Leishmania that assists in transmission and infection by sand fly bite. The resulting parasite burdens were low and the animals remained asymptomatic during a 2-year follow up period. However, this procedure did result in infection in 80% of the dogs and is appealing for future development as a natural challenge model in vaccine development.

  16. Experimental infection of dogs with Leishmania and saliva as a model to study Canine Visceral Leishmaniasis.

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    Dirceu Joaquim Costa

    Full Text Available BACKGROUND: Canine Visceral Leishmaniasis (CVL is a zoonotic disease caused by Leishmania infantum, transmitted by the bite of Lutzomyia longipalpis sand flies. Dogs are the main domestic reservoir of the parasite. The establishment of an experimental model that partially reproduces natural infection in dogs is very important to test vaccine candidates, mainly regarding those that use salivary proteins from the vector and new therapeutical approaches. METHODOLOGY/PRINCIPAL FINDINGS: In this report, we describe an experimental infection in dogs, using intradermal injection of Leishmania infantum plus salivary gland homogenate (SGH of Lutzomyia longipalpis. Thirty-five dogs were infected with 1×10(7 parasites combined with five pairs of Lutzomyia longipalpis salivary glands and followed for 450 days after infection and clinical, immunological and parasitological parameters were evaluated. Two hundred and ten days after infection we observed that 31,4% of dogs did not display detectable levels of anti-Leishmania antibodies but all presented different numbers of parasites in the lymph nodes. Animals with a positive xenodiagnosis had at least 3,35×10(5 parasites in their lymph nodes. An increase of IFN-γ and IL-10 levels was detected during infection. Twenty two percent of dogs developed symptoms of CVL during infection. CONCLUSION: The infection model described here shows some degree of similarity when compared with naturally infected dogs opening new perspectives for the study of CVL using an experimental model that employs the combination of parasites and sand fly saliva both present during natural transmission.

  17. Comportamiento experimental del Sporothrix schenckii y la Leishmania mexicana en el hamster Experimental behavior of Sporothrix schenckii and Leishmania mexicana in hamsters

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    Luz Angela González de Polanía

    1990-10-01

    Full Text Available La descripción macroscópica del proceso de patogénesis en hamsters inoculados subcutáneamente en nariz con Sporothrix schenckii ó Leishmania mexicana spp. proporcionó bases para diferenciar estos dos microorganismos en un modelo animal utilizado comunmente para estudiarlos. Observaciones secuenciales durante 150 días permitieron afirmar que en las infecciones causadas por estos patógenos se presentaron edema y eritema como signos primarios, seguidos de alopecia, necrosis y ulceración. La producción de pus fué una característica distintiva para el S. schenckii. Estos signos clínicos se observaron más temprano en la esporotricosis que en la infección por L. mexicana, mostrando diferencias estadísticas significantes en días promedio de aparición. El presente trabajo muestra que las lesiones producidas tanto por el S. schenckii como la L. mexicana en este modelo experimental comparten signos clínicos, pero el tiempo de aparición de los mismos y su frecuencia relativa permiten diferenciarlas. Las condiciones de inoculación como: cepa de los microorganismos, dosis del inóculo, sitio y vía de inoculación, deben tenerse presentes en la evaluación de su comportamiento experimental.The macroscopic description of the pathogenic process of Sporothrix schenckii and Leishmania mexicana spp in hamsters inoculated subcutaneously in the nose provided bases for the differentiation of the behavior of these two microorganisms in a model frequently utilized for their study. Sequential observations over 150 days demonstrated that infections caused by these pathogens results initially in edema and erythema followed by loss of hair, necrosis and ulceration. The pus production was a characteristic presented only by S. schenckii. These clinical signs were observed earlier in sporotrichosis than in L. mexicana infection. Differences in the mean day of appearance were statistically significant. The lesions produced by S. schenckii and L. mexicana

  18. Immunoinformatics Features Linked to Leishmania Vaccine Development: Data Integration of Experimental and In Silico Studies.

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    Brito, Rory C F; Guimarães, Frederico G; Velloso, João P L; Corrêa-Oliveira, Rodrigo; Ruiz, Jeronimo C; Reis, Alexandre B; Resende, Daniela M

    2017-02-10

    Leishmaniasis is a wide-spectrum disease caused by parasites from Leishmania genus. There is no human vaccine available and it is considered by many studies as apotential effective tool for disease control. To discover novel antigens, computational programs have been used in reverse vaccinology strategies. In this work, we developed a validation antigen approach that integrates prediction of B and T cell epitopes, analysis of Protein-Protein Interaction (PPI) networks and metabolic pathways. We selected twenty candidate proteins from Leishmania tested in murine model, with experimental outcome published in the literature. The predictions for CD4⁺ and CD8⁺ T cell epitopes were correlated with protection in experimental outcomes. We also mapped immunogenic proteins on PPI networks in order to find Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways associated with them. Our results suggest that non-protective antigens have lowest frequency of predicted T CD4⁺ and T CD8⁺ epitopes, compared with protective ones. T CD4⁺ and T CD8⁺ cells are more related to leishmaniasis protection in experimental outcomes than B cell predicted epitopes. Considering KEGG analysis, the proteins considered protective are connected to nodes with few pathways, including those associated with ribosome biosynthesis and purine metabolism.

  19. Immunity to Lutzomyia whitmani Saliva Protects against Experimental Leishmania braziliensis Infection.

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    Gomes, Regis; Cavalcanti, Katrine; Teixeira, Clarissa; Carvalho, Augusto M; Mattos, Paulo S; Cristal, Juqueline R; Muniz, Aline C; Miranda, José Carlos; de Oliveira, Camila I; Barral, Aldina

    2016-11-01

    Previous works showed that immunization with saliva from Lutzomyia intermedia, a vector of Leishmania braziliensis, does not protect against experimental infection. However, L. braziliensis is also transmitted by Lutzomyia whitmani, a sand fly species closely related to Lu. intermedia. Herein we describe the immune response following immunization with Lu. whitmani saliva and the outcome of this response after L. braziliensis infection. BALB/c mice immunized with Lu. whitmani saliva developed robust humoral and cellular immune responses, the latter characterized by an intense cellular infiltrate and production of IFN-γ and IL-10, by both CD4+ and CD8+ cells. Mice immunized as above and challenged with L. braziliensis plus Lu. whitmani saliva displayed significantly smaller lesions and parasite load at the challenge site. This protection was associated with a higher (p<0.05) IFN-γ production in response to SLA stimulation. Long-term persisting immunity was also detected in mice immunized with Lu. whitmani saliva. Furthermore, individuals residing in an endemic area for cutaneous leishmaniasis (CL) presented antibody responses to Lu. whitmani saliva. However CL patients, with active lesions, displayed a lower humoral response to Lu. whitmani saliva compared to individuals with subclinical Leishmania infection. Pre-exposure to Lu. whitmani saliva induces protection against L. braziliensis in a murine model. We also show that Lu. whitmani salivary proteins are immunogenic in naturally exposed individuals. Our results reinforce the importance of investigating the immunomodulatory effect of saliva from different species of closely related sand flies.

  20. Inoculação experimental de Equus asinus com Leishmania chagasi Cunha & Chagas, 1937 Experimental infection of Equus asinus with Leishmania chagasi Cunha & Chagas, 1937

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    Elúzio José Lima Cerqueira

    2003-12-01

    Full Text Available Quatro Equus asinus foram inoculados com promastigotas de Leishmania chagasi Cunha & Chagas, 1937 e acompanhados durante 12 meses através de: pesquisa de amastigotas em esfregaços e culturas de sangue periférico em fragmentos de tecido do lábio inferior, medula óssea, baço e fígado e de testes de ELISA e TRALd. Estes foram positivos nos 8º, 10º e 12º meses após a inoculação. O exame histopatológico pós necropsia, demonstrou discreto número de amastigotas no fígado de dois dos eqüídeos inoculados. Apesar de desafiados com elevado número de promastigotas, os animais não desenvolveram infecções patentes e não infectaram experimentalmente a vetora Lutzomya longipalpis. Os resultados induzem a acreditar que os eqüídeos são desprovidos de importância como reservatórios na cadeia de transmissão da leishmaniose visceral, embora sirvam como boa fonte de alimentação sangüínea e proliferação da vetora Lutzomyia longipalpis.Four Equus asinus were challenged with promastigotes of Leishmania chagasi Cunha & Chagas, 1937, and followed up for 12 months. They were observed by means of direct testing for promastigotes in smears and culture of peripheral blood, fragments from inferior lip, bone marrow, spleen and liver and the immunological assays ELISA and TRALd. The post-necropsy histological examination demonstrated a small number of amastigotes in the liver of two animals. ELISA and TRALd tests were positive at the 8th, 10th and 12th month after inoculation. The results suggest that the donkeys were able to overcome the experimental leishmanial infection and did not infect the vector Lutzomyia longipalpis in the laboratory. Consequently they can not be considered an important reservoir in the epidemiological chain of transmission of visceral leishmaniasis, although they represent an important blood source for the vector and its proliferation.

  1. Experimental infection and transmission of Leishmania by Lutzomyia cruzi (Diptera: Psychodidae: Aspects of the ecology of parasite-vector interactions.

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    Everton Falcão de Oliveira

    2017-02-01

    Full Text Available Several parameters should be addressed before incriminating a vector for Leishmania transmission. Those may include its ability to become infected by the same Leishmania species found in humans, the degree of attractiveness for reservoirs and humans and capacity to sustain parasite infection under laboratory conditions. This study evaluated the vectorial capacity of Lutzomyia cruzi for Leishmania infantum and gathered information on its ability to harbor L. amazonensis. Laboratory-reared Lu. cruzi were infected experimentally by feeding them on dogs infected naturally with L. infantum and hamsters infected with L. amazonensis. Sand fly attractiveness to dogs and humans was determined using wild caught insects. The expected daily survival of infected Lu. cruzi, the duration of the gonotrophic cycle, and the extrinsic incubation period were also investigated for both parasites. Vector competence was investigated for both Leishmania species. The mean proportion of female sand flies that fed on hosts was 0.40. For L. infantum and L. amazonensis, Lu. cruzi had experimental infection rates of 10.55% and 41.56%, respectively. The extrinsic incubation period was 3 days for both Leishmania species, regardless of the host. Survival expectancy of females infected with L. infantum and L. amazonensis after completing the gonotrophic cycle was 1.32 and 0.43, respectively. There was no association between L. infantum infection and sand fly longevity, but L. amazonensis-infected flies had significantly greater survival probabilities. Furthermore, egg-laying was significantly detrimental to survival. Lu. cruzi was found to be highly attracted to both dogs and humans. After a bloodmeal on experimentally infected hosts, both parasites were able to survive and develop late-stage infections in Lu. cruzi. However, transmission was demonstrated only for L. amazonensis-infected sand flies. In conclusion, Lu. cruzi fulfilled several of the requirements of vectorial

  2. Natural and experimental evidence of viscerotropic infection caused by Leishmania tropica from North Sinai, Egypt.

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    Doha, Said A; Shehata, Magdi G; Fahmy, Adel R; Samy, Abdallah M

    2014-08-01

    Cutaneous leishmaniasis (CL) is a neglected clinical form that is quite prevalent in Eastern North parts of the country in Sinai Peninsula. Leishmania tropica was identified by previous reports as the causative agent responsible for viscerotropic infections in-patients and experimental animals. Here, we reported the viscerotropic infections from naturally infected rodent Gerbillus pyramidum floweri collected from North-Sinai. Footpad and tail lesions, spleenomegaly, and malformed dark-colored spleen were the characteristic CL symptoms. The spleen of the rodent found positive to amastigote impression smear. ITS-1 DNA was sequenced and revealed 100% identity of the strain in the current study to the other L. tropica sequences identified from the patients with the suspected CL and inhabited the same study area. The current findings confirmed the susceptibility of gerbil to L. tropica, and raise the concerns for the role of rodents as accidental host suffering the infections. The susceptibility of wild and experimental rodents to the same L. tropica strain was also investigated; BALB/c and G. pyramidum were more susceptible to L. tropica (24.33 ± 4.37 and 25 ± 4.58 days post-infection, respectively). Similar viscerotropic pathologies were reported in experimental infection of only golden hamster (≈ 120 days post-infection), and G. p. floweri (≈ 160 days post-infection).

  3. Prophylactic potential of autoclaved Leishmania donovani with BCG against experimental visceral leishmaniasis.

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    Srivastava, J K; Misra, A; Sharma, P; Srivastava, B; Naik, S; Dube, A

    2003-08-01

    The prophylactic efficacy of autoclaved Leishmania donovani (ALD) and autoclaved L. major (ALM)--a heterologous vaccine developed against cutaneous leishmaniasis (used as a reference vaccine), along with BCG--was evaluated against L. donovani in hamsters (Mesocricetus auratus). Animals were immunized with triple doses (21 days apart) of either ALD or ALM (1.0 mg) with or without BCG (0.1 mg) and challenged 21 days later with 1 x 10(6) L. donovani amastigotes intracardially. Animals immunized with ALM + BCG and ALD + BCG yielded 94.3% and 86.1% parasite inhibition respectively in comparison to the BCG only and unvaccinated controls. Fifty and 33.3% of the vaccinated animals (ALM + BCG and ALD + BCG respectively) were completely devoid of parasites when tested on day 45 post-challenge (p.c.) and survived till the experiment was terminated. The mean survival of ALM + BCG and ALD + BCG groups (animals harbouring parasites) was longest (168 and 139 days respectively). No significant increase in anti-leishmanial antibody level (ELISA) was noticed in ALD + BCG and ALM + BCG groups whereas it increased progressively in the rest of the experimental groups. The lymphoproliferative responses to PHA and Con A, of the 2 vaccinated groups were comparable to that of normal controls on day 45 p.c. The study suggests that ALD along with BCG can offer substantial protection against visceral leishmaniasis in hamsters.

  4. An experimental challenge model of visceral leishmaniasis by Leishmania donovani promastigotes in mice.

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    Katakura, Ken

    2016-10-01

    Although visceral leishmaniasis is a fatal disease in humans and dogs, the use of mouse models is important for obtaining a better understanding of the pathogenesis, immunity, and host-parasite interactions of this disease. Such models are also useful for the evaluation of vaccines and chemotherapies for treatment of visceral leishmaniasis. Here, we present our method of experimental inoculation of mice with Leishmania donovani promastigotes. Nutrient-enriched undefined media may be beneficial for laboratory maintenance of promastigotes for maintaining their virulence or infectivity in mice. With this method, we could preserve the infectivity of promastigote lines recovered from inoculated animals and use these lines for further in vivo experiments. Furthermore, the use of cryopreserved stabilates is highly recommended for the reproducibility of experiments. To assess a newly developed method for determination of parasite burden in infected animal tissues, initial comparison of parasite burden in the liver obtained in the classic Leishman-Donovan units (LDU) with values obtained from the new method is recommended. As an example, the association between parasite burden determined by LDU and real-time PCR assay targeting the leishmanial gp63 gene in the liver of mice is presented. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  5. Efficacy of Leishmania donovani ribosomal P1 gene as DNA vaccine in experimental visceral leishmaniasis.

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    Masih, Shet; Arora, Sunil K; Vasishta, Rakesh K

    2011-09-01

    The acidic ribosomal proteins of the protozoan parasites have been described as prominent antigens during human disease. We present here data showing the molecular cloning and protective efficacy of P1 gene of Leishmania donovani as DNA vaccine. The PCR amplified complete ORF cloned in either pQE or pVAX vector was used either as peptide or DNA vaccine against experimentally induced visceral leishmaniasis in hamsters. The recombinant protein rLdP1 was given along with Freund's adjuvant and the plasmid DNA vaccine, pVAX-P1 was used alone either as single dose or double dose (prime and boost) in different groups of hamsters which were subsequently challenged with a virulent dose of 1×10(7) L. donovani (MHOM/IN/DD8/1968 strain) promastigotes by intra-cardiac route. While the recombinant protein rLdP1 or DNA vaccine pVAX-P1 in single dose format were not found to be protective, DNA vaccine in a prime-boost mode was able to induce protection with reduced mortality, a significant (75.68%) decrease in splenic parasite burden and increased expression of Th1 type cytokines in immunized hamsters. Histopathology of livers and spleens from these animals showed formation of mature granulomas with compact arrangement of lymphocytes and histiocytes, indicating its protective potential as vaccine candidate. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Experimental Leishmania major infection suppresses HIV-1 DNA vaccine induced cellular immune response.

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    Robinson, Tara M; Nelson, Robin; Artis, David; Scott, Phillip; Boyer, Jean D

    2004-01-01

    The AIDS epidemic in the developing world represents a major global crisis and an effective vaccine is imperative. However, many parasites are common in developing countries and can result in a state of chronic immune activation that is polarized towards a Th2 profile and which can potentially impair responses to vaccines or other infectious challenges. In this study we demonstrate that experimental Leishmania major infection of BALB/c mice inhibits responses to a DNA-based HIV-1 gag vaccine. L. major infection in BALB/c results in a polarized Th2 immune response. In this study naïve BALB/c mice immunized with the HIV-1 gag DNA vaccine mounted a cellular immune response against the vaccine antigen, HIV-1 gag. CD8+ T lymphocytes were able to respond in vitro to HIV-1 gag stimulation and secrete interferon (IFN)-gamma. However, L. major-infected, vaccinated BALB/c mice had a significantly reduced number of IFN-gamma-producing CD8+ T cells following in vitro stimulation with gag antigen. These data suggest that parasitic infection, which results in a Th2 profile, reduces the efficacy of DNA vaccines that are designed to induce antiviral CD8+ T cell responses. Copyright 2004 S. Karger AG, Basel

  7. In vitro binding and survival assays of Leishmania parasites to peripherical blood monocytes and monocyte-derived macrophages isolated from dogs naturally and experimentally infected with Leishmania (Leishmania chagasi

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    Tafuri Washington L

    2007-05-01

    Full Text Available Abstract Background There are a few works considering the characterization of canine monocyte-derived macrophages as well as a standardized procedure for isolation, culture, and infection of these cells with Leishmania. We have performed several modifications in order to improve the canine monocyte-derived macrophage cultures. In addition, we have done a comparative study between monocytes and monocyte-derived macrophages from dogs naturally and experimentally infected with L. chagasi. Results In the presence of exogenous serum, opsonized Leishmania promastigotes binds better to monocytes/macrophages than without serum. Otherwise, this binding occurs due to the strict correlation between the opsonized biologic particles with the third receptor of the complement (CR3-CD11b/CD18. In fact, our assays with CD11b confirmed the importance of this receptor for canine cells and the L. chagasi experimental system. Moreover, monocytes obtained from naturally infected dogs have shown a higher number of monocytes bounded to promastigotes. The experimental results regarding survival have shown that promastigote forms of opsonized L. chagasi were more infective, because we found higher numbers of promastigotes bound to the different cells. As a consequence, after forty-eight hours of binding, higher numbers of amastigotes appeared inside monocyte-macrophages. Conclusion These studies have given support to continue comparative studies involving canine monocytes, monocyte-derived macrophages and peritoneal macrophages. Since we have standardized the canine cell culture, we are looking forward to determining the phenotypic properties of these cells before and after L. chagasi infection using flow cytometry.

  8. Experimental therapeutic studies of Solanum aculeastrum Dunal. on Leishmania major infection in BALB/c mice.

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    Laban, Linet T; Anjili, Christopher O; Mutiso, Joshua M; Ingonga, Johnstone; Kiige, Samuel G; Ngedzo, Mgala M; Gicheru, Michael M

    2015-01-01

    Solanum acueastrum Dunal. has been shown to have some chemotherapeutic value. Leaf and berry water and methanol compounds of S. acueastrum were evaluated for possible antileishmanial activity In vivo on BALB/c mice and in vitro against Leishmania major promastigotes, amastigotes and vero cells. Dry S. aculeastrum berry and leaf material were extracted in methanol and water. L. major parasites were exposed to different concentrations of S. aculeastrum fruit and leaf compounds and the IC50 on the promastigotes, percentage of infection rate of macrophages by amastigotes and the toxicological effect on vero cells were determined. BALB/c mice were infected subcutaneously with 1×10(6) promastigotes and kept for four weeks to allow for disease establishment. Infected mice were treated with fruit and leaf methanolic and water compounds, amphotericin B (AmB), and sterile phosphate buffered saline (PBS). Fruit methanol compound was most effective in inhibiting the growth of promastigotes with IC5078.62 μg/ml. Fruit water compound showed the best activity in inhibiting infection of macrophages by amastigotes. Fruit methanol compound was more toxic at Ld50=8.06 mg/ml to vero cells than amphotericin B. Analysis of variance computation indicated statistically significant difference in lesion sizes between experimental and control mice groups (P=0.0001). Splenic impression smears ANOVA indicated a highly significant difference in parasitic numbers between the experimental and the control groups (P=0.0001). The results demonstrate that compounds from S. aculeastrum have potential anti-leishmanial activities and the medicinal use of the plant poses considerable toxicity against dividing vero cells.

  9. Experimental Evaluation of Second-Line Oral Treatments of Visceral Leishmaniasis Caused by Leishmania infantum

    OpenAIRE

    Gangneux, Jean-Pierre; Dullin, Michael; Sulahian, Annie; Garin, Yves Jean-Francois; Derouin, Francis

    1999-01-01

    In a murine model of Leishmania infantum visceral leishmaniasis, metronidazole, ketoconazole, fluconazole, itraconazole, and terbinafine were less effective than antimonial agents in reducing hepatic parasite load. Ketoconazole potentiated the effect of meglumine antimoniate reference therapy through its marked activity against spleen infection.

  10. Excreción de promastigotos de Leishmania pifanoi por Lutzomyia youngi experimentalmente infectada Excretion of promastigotos of Leishmania pifanoi by experimentally infected Lutzomyia youngi

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    Elina Rojas

    1995-12-01

    Full Text Available Se describe el desarrollo poblacional promastigótico de Leishmania pifanoi en Lutzomyia youngi experimentalmente infectada y mantenida con sacarosa al 50% bajo condiciones constantes de temperatura y humedad. Se reconocen dos etapas para la diferenciación y el crecimiento de los parásitos entre las dos y ciento veinte horas postprandiales. Hasta 48 horas tiene lugar la diferenciación pleomórfica de amastigotos en promastigotos cortos, que se multiplican por división binaria hasta las 60 horas, cuando ocurre la ruptura de la membrana peritrófica. La segunda etapa tiene lugar entre las 72 y 96 horas cuando algunos parásitos migran hacia la válvula esofágica y los demás parásitos libres son excretados en gotitas fecales como promastigotos grandes y activos. Las primeras gotitas excretadas dan reacción positiva a glucosa o contienen cristales de urato. El exceso de promastigotos de la segunda fase de desarrollo es eliminado en las últimas excretas que dan reacción positiva con las pruebas Hemoscreen y Biuret para proteínas totales y también para glucosa, y constituyen el 82% del total de gotas excretadas. La excreción de parásitos por Lu. youngi es fase normal del desarrollo de L. pifanoi en un vector.The increase in the promastigotes population of Leishmania pifanoi in Lutzomyia youngi experimentally infected and kept on 50% sacarose under constant conditions of temperature and humidity is described. Two stages in the differentation and growth of the parasites are recognised between two and twenty-four hours after meals. The pleomorphic differentiation of the amastigotes in short promastigotes which multiply by binary division for 60 hours, when the rupture of the peritrophic membrane occurs, takes place within 48 hours. The second stage occurs between 72 and 96 hours when some of the parasites migrate to the esophagic valve and the rest of the free parasites are excreted in fecal drops as large, active promastigotes. The first

  11. Experimental Acquisition, Development, and Transmission of Leishmania tropica by Phlebotomus duboscqi

    Science.gov (United States)

    2013-01-01

    Leishmania. Use of isoenzymes. Suggestions for a new classification. Annales de Parasitologie Humaine et Comparee 65, 111–125. Rogers, M.E., Chance, M.L...the National Academy of Sciences of the United States of America 97, 406–411. Sacks, D., Kamhawi, S., 2001. Molecular aspects of parasite–vector and...feeding mechanism of the sandfly vector and implement parasite transmission by bite. Proceedings of the National Academy of Sciences of the United

  12. The Effect of Ursolic Acid on Leishmania (Leishmania amazonensis Is Related to Programed Cell Death and Presents Therapeutic Potential in Experimental Cutaneous Leishmaniasis.

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    Eduardo S Yamamoto

    Full Text Available Among neglected tropical diseases, leishmaniasis is one of the most important ones, affecting more than 12 million people worldwide. The available treatments are not well tolerated, and present diverse side effects, justifying the search for new therapeutic compounds. In the present study, the activity of ursolic acid (UA and oleanolic acid (OA were assayed in experimental cutaneous leishmaniasis (in vitro and in vivo. Promastigote forms of L. amazonensis were incubated with OA and UA for 24h, and effective concentration 50% (EC50 was estimated. Ultraestructural alterations in Leishmania amazonensis promastigotes after UA treatment were evaluated by transmission electron microscopy, and the possible mode of action was assayed through Annexin V and propidium iodide staining, caspase 3/7 activity, DNA fragmentation and transmembrane mitochondrial potential. The UA potential was evaluated in intracellular amastigotes, and its therapeutic potential was evaluated in L. amazonensis infected BALB/c mice. UA eliminated L. amazonensis promastigotes with an EC50 of 6.4 μg/mL, comparable with miltefosine, while OA presented only a marginal effect on promastigote forms at 100 μg/mL. The possible mechanism by which promastigotes were eliminated by UA was programmed cell death, independent of caspase 3/7, but it was highly dependent on mitochondria activity. UA was not toxic for peritoneal macrophages from BALB/c mice, and it was able to eliminate intracellular amastigotes, associated with nitric oxide (NO production. OA did not eliminate amastigotes nor trigger NO. L. amazonensis infected BALB/c mice submitted to UA treatment presented lesser lesion size and parasitism compared to control. This study showed, for the first time, that UA eliminate promastigote forms through a mechanism associated with programed cell death, and importantly, was effective in vivo. Therefore, UA can be considered an interesting candidate for future tests as a prototype drug for

  13. The Effect of Ursolic Acid on Leishmania (Leishmania) amazonensis Is Related to Programed Cell Death and Presents Therapeutic Potential in Experimental Cutaneous Leishmaniasis.

    Science.gov (United States)

    Yamamoto, Eduardo S; Campos, Bruno L S; Jesus, Jéssica A; Laurenti, Márcia D; Ribeiro, Susan P; Kallás, Esper G; Rafael-Fernandes, Mariana; Santos-Gomes, Gabriela; Silva, Marcelo S; Sessa, Deborah P; Lago, João H G; Levy, Débora; Passero, Luiz F D

    2015-01-01

    Among neglected tropical diseases, leishmaniasis is one of the most important ones, affecting more than 12 million people worldwide. The available treatments are not well tolerated, and present diverse side effects, justifying the search for new therapeutic compounds. In the present study, the activity of ursolic acid (UA) and oleanolic acid (OA) were assayed in experimental cutaneous leishmaniasis (in vitro and in vivo). Promastigote forms of L. amazonensis were incubated with OA and UA for 24h, and effective concentration 50% (EC50) was estimated. Ultraestructural alterations in Leishmania amazonensis promastigotes after UA treatment were evaluated by transmission electron microscopy, and the possible mode of action was assayed through Annexin V and propidium iodide staining, caspase 3/7 activity, DNA fragmentation and transmembrane mitochondrial potential. The UA potential was evaluated in intracellular amastigotes, and its therapeutic potential was evaluated in L. amazonensis infected BALB/c mice. UA eliminated L. amazonensis promastigotes with an EC50 of 6.4 μg/mL, comparable with miltefosine, while OA presented only a marginal effect on promastigote forms at 100 μg/mL. The possible mechanism by which promastigotes were eliminated by UA was programmed cell death, independent of caspase 3/7, but it was highly dependent on mitochondria activity. UA was not toxic for peritoneal macrophages from BALB/c mice, and it was able to eliminate intracellular amastigotes, associated with nitric oxide (NO) production. OA did not eliminate amastigotes nor trigger NO. L. amazonensis infected BALB/c mice submitted to UA treatment presented lesser lesion size and parasitism compared to control. This study showed, for the first time, that UA eliminate promastigote forms through a mechanism associated with programed cell death, and importantly, was effective in vivo. Therefore, UA can be considered an interesting candidate for future tests as a prototype drug for the treatment

  14. Activity of synthetic chalcones in hamsters experimentally infected with Leishmania (Viannia) braziliensis.

    Science.gov (United States)

    de Mello, Tatiane F P; Cardoso, Bruna M; Lopes, Sara N; Bitencourt, Heriberto R; Voltarelli, Evandra M; Hernandes, Luzmarina; Aristides, Sandra M A; Lonardoni, Maria V C; Silveira, Thais G V

    2015-10-01

    The purpose of this study is to evaluate the toxicity of synthetic chalcones 1 and 2 in uninfected hamsters and anti-Leishmania activity of synthetic chalcones 1 and 2 in hamsters infected with Leishmania (Viannia) braziliensis. For the toxicity test, uninfected animals were treated with chalcones 1 and 2, and clinical and biochemical parameters and histological aspects of the liver and kidneys were assessed. Chalcones 1 and 2 were then intraperitoneally or topically administered (10 mg/kg body weight) three times per week in animals infected with promastigotes of L. (V.) braziliensis. We monitored the thickness of the infected footpads, determined parasitic load, performed histological analysis, and detected apoptosis in situ. The results were analyzed using Student's t test and Mann-Whitney test at a significance level of 5%. Neither of the chalcones showed toxicity. Chalcone 2 administered intraperitoneally significantly reduced the thickness of the infected footpad compared with the beginning of treatment. The parasite load of the lymph node and spleen was reduced in the groups treated with chalcones 1 (topical) and 2 (intraperitoneal). Chalcone 2 (topical) reduced parasite burden only in the lymph node. The histological analysis revealed reconstitution of the tissue and reductions of inflammation and apoptosis in the infected footpad in these groups. The synthetic chalcones 1 (topical) and 2 (intraperitoneal and topical) at a dose of 10 mg/kg showed anti-Leishmania activity in vivo, no renal or hepatic toxicity, and a reduction of apoptosis of the cells in the lesions. These chalcones may have substantial potential for the treatment of cutaneous leishmaniasis.

  15. Transcriptome profiling identifies genes/pathways associated with experimental resistance to paromomycin in Leishmania donovani

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    Aditya Verma

    2017-12-01

    Full Text Available Widespread resistance towards antimony and reports of relapses following miltefosine treatment has severely affected the management of visceral leishmaniasis (VL in the Indian subcontinent. Paromomycin (PMM, an aminoglycoside antibiotic, has been licensed for VL treatment in India in 2007. Although its use is still restricted in the field, unraveling the molecular mechanism of resistance towards PMM is the key to preserve the drug. In this study, PMM resistant lines were selected up to 100 μM of PMM in three distinct field isolates of Leishmania donovani at promastigote stage. The resistance induced at promastigote level was also evident in amastigotes which showed 6 fold decreases in PMM susceptibility. Comparative transcriptome profiling of PMM resistant (PMM-R and the corresponding PMM sensitive (PMM-S parasites revealed modulated expression of 500 genes (1.5 fold cut off in PMM-R parasites. Selected genes were validated for their modulated expression by quantitative real-time PCR. Functional classification and pathway analysis of modulated genes indicated probable adaptations in drug resistant lines which included a reduced oxidative phosphorylation; b increased glycosomal succinate fermentation and substrate level phosphorylation; c dependency on lipids and amino acids for energy generation; d reduced DNA synthesis and increased DNA damage repair and e decreased protein synthesis and degradation. Interestingly, PMM-R parasites showed a marked increase in PMM susceptibility in presence of verapamil and amlodipine, antagonists of Ca2+ channel that are also modulators of ABC transporters. Moreover, infection of macrophages by PMM-R parasites led to modulated nitric oxide (NO levels while reactive oxygen species (ROS level remained unaltered. The present study highlights the putative mechanisms of PMM resistance in Leishmania. Keywords: Leishmania donovani, Drug resistance, Paromomycin, Transcriptome, ABC transporters, Nitric oxide

  16. Experimental infection of canine peritoneal macrophages with visceral and dermotropic Leishmania strains

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    Madeira MF

    1999-01-01

    Full Text Available A study was carried out using macrophages cultured from the peritoneal exudate of dogs infected in vitro with three species of Leishmania: L. (L. chagasi, L. (Viannia braziliensis and L. (L. amazonensis with the aim of investigating the growth kinetics and infectivity of these species in the host cell. Results were expressed as the percentage of macrophages infected measured at 24 hr intervals over six days in RPMI - 1640 culture medium at a temperature of 34-35oC. The findings open the possibility of using canine peritoneal cells as a model for the screenning of leishmanicide drugs and to study the pathogenesis of these species.

  17. SIGNR1-Negative Red Pulp Macrophages Protect against Acute Streptococcal Sepsis after Leishmania donovani-Induced Loss of Marginal Zone Macrophages

    NARCIS (Netherlands)

    Kirby, A.C.; Beattie, L.; Maroof, A.; Rooijen, van N.; Kaye, P.M.

    2009-01-01

    Marginal zone macrophages in the murine spleen play an important role in the capture of blood-borne pathogens and are viewed as an essential component of host defense against the development of pneumococcal sepsis. However, we and others have previously described the loss of marginal zone

  18. Experimental Leishmania (L.) amazonensis leishmaniasis: characterization and immunogenicity of subcellular fractions.

    Science.gov (United States)

    do Valle, T Zaverucha; Gaspar, E B; Souza-Lemos, C; Souza, C S F; Márquez, F B Zamora; Baetas-da-Cruz, W; d'Escofier, L N; Côrte-Real, S; Calabrese, K S; da Costa, S C Gonçalves

    2007-01-01

    A technique developed in Trypanosoma cruzi biochemical studies was successfully used to fractionate Leishmania (Leishmania) amazonensis promastigotes. Ultrastructural analyses revealed a membrane fraction (MF) associated to subpellicular microtubules, a ribosomal-rich microsomal fraction (MicF), and a flagellar fraction (FF) free of associated membrane. All fractions proved to be immunogenic through delayed type hypersensitivity reaction assays. Therefore, a protocol was designed to test whether these fractions could elicit a protective response in mice infected by L. (L), amazonensis. The protocol consisted of a BCG injection (as cellular immunity inducer), followed by cyclophosphamide (once its cytotoxic effect is over, this immunosuppressor can increase the number of circulating leukocytes), then an injection with one of the fractions followed by a challenge. When compared to infected control animals, mice injected with any of the fractions presented a smaller footpad swelling, especially those injected with MicF or FF. Macroscopically, immunized mice under modulation by BCG presented no swelling. Histopathological studies performed on day 120 revealed fewer amastigotes and more intense inflammation in lesions of MicF and FF injected mice. Animals injected with MF presented an intermediate pattern. Parasite quantification corroborated these results. The results show that all fractions are potent immunostimulators, but MicF and FF have the strongest protective ability.

  19. Gentamicin-attenuated Leishmania infantum: cellular immunity production and protection of dogs against experimental canine leishmaniasis.

    Science.gov (United States)

    Daneshvar, H; Molaei, M M; Kamiabi, H; Burchmore, R; Hagan, P; Stephen Phillips, R

    2010-01-01

    An attenuated line of Leishmania infantum (L. infantum H-line) has been established by culturing promastigotes in vitro under gentamicin pressure. Here, we show that L. infantum H-line induced significantly higher levels of IFN-γ and lower levels of IL-10 compared with those in dogs infected with L. infantum wild type (WT). Anti-Leishmania-specific total IgG, IgG1, and IgG2 antibodies were present in the serum of all infected dogs, with levels of IgG2 subclass highest in the sera of dogs inoculated with L. infantum H-line. Relatively high levels of IgG1 were found in the sera of dogs infected with L. infantum WT. Six of seven dogs immunized intradermally (i.d.) with the attenuated line later showed a positive skin test to leishmanin, whereas the dogs infected with L. infantum WT did not. No clinical abnormalities were observed, and no parasites found in the visceral organs of the dogs inoculated intravenously (i.v.) with L. infantum H-line over 24 months post-inoculation. Dogs which had been immunized with L. infantum H-line i.d. 12 months previously were protected against challenge with L. infantum WT. These data suggest that the L. infantum H-line was safe and induced a protection which is correlated with cellular immunity in dogs. © 2010 Blackwell Publishing Ltd.

  20. Combined treatment of miltefosine and paromomycin delays the onset of experimental drug resistance in Leishmania infantum.

    Science.gov (United States)

    Hendrickx, Sarah; Van den Kerkhof, Magali; Mabille, Dorien; Cos, Paul; Delputte, Peter; Maes, Louis; Caljon, Guy

    2017-05-01

    Since miltefosine monotherapy against visceral leishmaniasis (VL) caused by Leishmania donovani has been discontinued in the Indian subcontinent due to an increase in the number of treatment failures, single dose liposomal amphotericin B is now advocated as a treatment option of choice. Paromomycin-miltefosine combination therapy can be used as substitute first-line treatment in regions without cold-chain potential. Previous laboratory studies in the closely related species Leishmania infantum have demonstrated that paromomycin monotherapy fairly rapidly selects for resistance producing a phenotype with increased fitness. Given the possible clinical implications of these findings for the current field situation, the present study aimed to identify the potential hazards of paromomycin-miltefosine combination therapy. Drug interaction studies using the fixed-ratio isobologram method revealed an indifferent interaction between paromomycin and miltefosine. In hamsters infected with L. infantum, the combination resulted in cumulative efficacy in reducing parasite burdens in the liver, spleen and bone marrow. Selected resistant lines against the single drugs did not display cross-resistance. When the intracellular amastigote stage was repeatedly exposed to the paromomycin-miltefosine combination, either in vitro or in vivo, no significant susceptibility decrease towards either drug was noted. These results suggest that implementation of paromomycin-miltefosine combination therapy indeed could represent a safe and affordable treatment option for L. donovani VL as miltefosine appears to overrule the anticipated rapid development of PMM resistance.

  1. Combined treatment of miltefosine and paromomycin delays the onset of experimental drug resistance in Leishmania infantum.

    Directory of Open Access Journals (Sweden)

    Sarah Hendrickx

    2017-05-01

    Full Text Available Since miltefosine monotherapy against visceral leishmaniasis (VL caused by Leishmania donovani has been discontinued in the Indian subcontinent due to an increase in the number of treatment failures, single dose liposomal amphotericin B is now advocated as a treatment option of choice. Paromomycin-miltefosine combination therapy can be used as substitute first-line treatment in regions without cold-chain potential. Previous laboratory studies in the closely related species Leishmania infantum have demonstrated that paromomycin monotherapy fairly rapidly selects for resistance producing a phenotype with increased fitness. Given the possible clinical implications of these findings for the current field situation, the present study aimed to identify the potential hazards of paromomycin-miltefosine combination therapy.Drug interaction studies using the fixed-ratio isobologram method revealed an indifferent interaction between paromomycin and miltefosine. In hamsters infected with L. infantum, the combination resulted in cumulative efficacy in reducing parasite burdens in the liver, spleen and bone marrow. Selected resistant lines against the single drugs did not display cross-resistance. When the intracellular amastigote stage was repeatedly exposed to the paromomycin-miltefosine combination, either in vitro or in vivo, no significant susceptibility decrease towards either drug was noted.These results suggest that implementation of paromomycin-miltefosine combination therapy indeed could represent a safe and affordable treatment option for L. donovani VL as miltefosine appears to overrule the anticipated rapid development of PMM resistance.

  2. The transmission of suprapylarian Leishmania by bite of experimentally infected sand flies (Diptera: Psychodidae A trasnmissão de Leishmania suprapilária pela picada do flebotomíneo infectado experimentalmente

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    L. Ryan

    1987-09-01

    Full Text Available Lutzomyia furcata transmitted Leishmania chagasi to a hamster 10 days after being experimentally fed on an infected spleen. An individual female Psychodopygus carrerai carrerai that had fed on a hamster lesion caused by Leishmania mexicana amazonensis transmitted this parasite 6 days later to another hamster. Transmission electron microscopy of this fly's head revealed a small number of degenerate promastigotes in the foregut, but only a few were attached.O protozoário Leishmania (L. chagasi foi transmitido experimentalmente a um hamster pela picada do flebotomíneo Lutzomyia furcata. Os insetos foram infectados através de uma membrana (pele de pinto, utilizando-se formas amastigotas provenientes do baço de um hamster infectado. O baço foi triturado em sangue de coelho. A L. (L. amazonensis foi transmitida a um hamster pela picada do flebotomíneo Psychodopygus c. carrerai, previamente alimentado em lesão de pele de um outro hamster infectado com o parasita. O exame desse flebotomíneo, através de microscópio eletrônico, revelou um número pequeno de flagelados degenerados, livres no lumen do intestino anterior.

  3. Leishmania major MAP kinase 10 is protective against experimental L. major infection.

    Science.gov (United States)

    Kumari, Sangeeta; Singh, Sushma; Saha, Bhaskar; Paliwal, Piyush Kumar

    2011-11-08

    Leishmania, a protozoan parasite that resides and replicates obligatorily within macrophages, inflicts a complex of severe diseases known as leishmaniasis. The diseases have significant socio-economic impact through gross disfiguration, morbidity and mortality worldwide. Despite these problems, an effective anti-leishmanial vaccine remains elusive. Herein, we have analyzed the immunogenicity and protective efficacy of L. major MAP kinase 10 (LmjMAPK10) against the challenge infection with the parasite. We observe significant protection against the infection by LmjMAPK10 priming of BALB/c mouse strain, a susceptible host. The resistance to the infection is generally associated with mixed Th1/Th2 responses to the infection following immunization with LmjMAPK10 DNA or protein or a combination of both DNA and protein. Therefore, LmjMAPK10 is a probable vaccine candidate against the infection. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Cell-mediated immune response to Leishmania chagasi experimental infection of BALB/c immunosuppressed mice

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    JG Machado

    2010-01-01

    Full Text Available Leishmaniasis, a zoonosis of worldwide distribution, presents a significant impact on immunosupressed patients. This study aimed to evaluate Leishmania chagasi infection in BALB/c mice immunosuppressed with dexamethasone. Spleen cells stimulated or not with L. chagasi were cultured for cytokine quantification (IFN-γ, IL-2, IL-4 and IL-10 by sandwich ELISA. Parasite loads in the spleen and liver were determined by means of culture microtitration. Immunosuppressed groups showed statistically lower spleen weight and CD4-cell percentage in blood on the day of infection and produced Th1 and Th2 cytokines on other days of the study. The other infected groups, weather immunosupressed or not, also produced Th1 and Th2 cytokines. Parasite loads in the spleen and liver were not statistically different among the groups. It was concluded that L. chagasi infection was not affected by dexamethasone-induced immunosuppression, probably due the reversible effect of the treatment.

  5. Experimental canine leishmaniasis: evolution of infection following re-challenge with Leishmania infantum.

    Science.gov (United States)

    Santos-Gomes, Gabriela M; Capela, Maria José Riça; Ramada, João; Campino, Lenea

    2003-07-01

    The aim of the study was to assess the clinical, parasitological and immunological effect of a second inoculation of amastigotes in dogs previously inoculated with Leishmania infantum. Three dogs primarily inoculated with amastigotes (Group I) and four with cultured virulent stationary phase promastigotes (Group II) were afterwards re-inoculated with 2x10(9) amastigotes per kg. Three other groups of dogs were used as controls: Group III was infected only once with amastigotes, Group IV only once with promastigotes and Group V was non infected. The animals were followed up by clinical and parasitological examinations, hematological and serum protein analysis, anti-leishmanial antibody levels and proliferative assays of specific peripheral blood mononuclear cells over a period up to 50 months. Parasites were isolated from lymph node of three animals during primary amastigote infection and in five animals (Group I and II) after re-challenge. Group I dogs presented a strong increase of the humoral immune response while Group II animals displayed no significant or significantly low antileishmanial antibodies titres, after re-challenge. The detection, only after challenge, of positive specific lymphoproliferation in two animals of Group II that had the longest primary infection interval (more than 26 months), indicates the requirement of a long time interval to obtain specific lymphocyte sensitization. A previous exposure to virulent cultured L. infantum promastigotes seems to confer some degree of resistance against an amastigote infection.

  6. Thrichomys laurentius (Rodentia; Echimyidae as a putative reservoir of Leishmania infantum and L. braziliensis: patterns of experimental infection.

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    André Luiz Rodrigues Roque

    Full Text Available The importance of the genus Thrichomys in the retention of infection and transmission of Leishmania species is supported by previous studies that describe an ancient interaction between caviomorphs and trypanosomatids and report the natural infection of Thrichomys spp. Moreover, these rodents are widely dispersed in Brazil and recognized as important hosts of other tripanosomatids. Our main purpose was to evaluate the putative role of Thrichomys laurentius in the retention of infection and amplification of the transmission cycle of Leishmania infantum and L. braziliensis. Male and female T. laurentius (n = 24 born in captivity were evaluated for the retention of infection with these Leishmania species and followed up by parasitological, serological, hematological, biochemical, histological, and molecular assays for 3, 6, 9, or 12 months post infection (mpi. T. laurentius showed its competence as maintenance host for the two inoculated Leishmania species. Four aspects should be highlighted: (i re-isolation of parasites 12 mpi; (ii the low parasitic burden displayed by T. laurentius tissues; (iii the early onset and maintenance of humoral response, and (iv the similar pattern of infection by the two Leishmania species. Both Leishmania species demonstrated the ability to invade and maintain itself in viscera and skin of T. laurentius, and no rodent displayed any lesion, histological changes, or clinical evidence of infection. We also wish to point out the irrelevance of the adjective dermotropic or viscerotropic to qualify L. braziliensis and L. infantum, respectively, when these species are hosted by nonhuman hosts. Our data suggest that T. laurentius may act at least as a maintenance host of both tested Leishmania species since it maintained long-lasting infections. Moreover, it cannot be discarded that Leishmania spp. infection in free-ranging T. laurentius could result in higher parasite burden due the more stressing conditions in the wild

  7. Immunization with H1, HASPB1 and MML Leishmania proteins in a vaccine trial against experimental canine leishmaniasis.

    Science.gov (United States)

    Moreno, J; Nieto, J; Masina, S; Cañavate, C; Cruz, I; Chicharro, C; Carrillo, E; Napp, S; Reymond, C; Kaye, P M; Smith, D F; Fasel, N; Alvar, J

    2007-07-20

    The protective capabilities of three Leishmania recombinant proteins - histone 1 (H1) and hydrophilic acylated surface protein B1 (HASPB1) immunized singly, or together as a protein cocktail vaccine with Montanide, and the polyprotein MML immunized with MPL-SE adjuvant - were assessed in beagle dogs. Clinical examination of the dogs was carried out periodically under blinded conditions and the condition of the dogs defined as asymptomatic or symptomatic. At the end of the trial, we were able to confirm that following infection with L. infantum promastigotes, five out of eight dogs immunized with H1 Montanide, and four out of eight dogs immunized with either the combination of HASPB1 with Montanide or the combination of H1+HASPB1 with Montanidetrade mark, remained free of clinical signs, compared with two out of seven dogs immunized with the polyprotein MML and adjuvant MPL-SE, and two out of eight dogs in the control group. The results demonstrate that HASPB1 and H1 antigens in combination with Montanide were able to induce partial protection against canine leishmaniasis, even under extreme experimental challenge conditions.

  8. Evaluation of vaccinal effectiveness of preparations containing membrane antigens of Leishmania (L.) amazonensis in experimental cutaneous leishmaniasis model.

    Science.gov (United States)

    Ribeiro, João G; Ferreira, Amália S; Macedo, Sharon R A; Rossi, Norton R D L P; da Silva, Mayara C P; Guerra, Rosane N M; de Barros, Neuza B; Nicolete, Roberto

    2017-06-01

    American tegumentary leishmaniasis (ATL) is considered a neglected disease, for which an effective vaccine or an efficient diagnosis is not yet available and whose chemotherapeutic arsenal is threatened by the emergence of resistance by etiological agents such as Leishmania amazonensis. ATL is endemic in poor countries and has a high incidence in Brazil. Vaccines developed from native parasite fractions have led to the identification of defined antigenic subunits and the development of vaccine adjuvant technology. The purpose of the present study was to develop and compare preparations based on membrane antigens from L. amazonensis, as a biotechnological prototype for the immunoprophylaxis of the disease in a murine experimental model. For this purpose, batches of biodegradable polymeric micro/nanoparticles were produced, characterized and compared with other parasite's antigens in solution. All preparations containing membrane antigens presented low toxicity on murine macrophages. The in vivo evaluation of immunization efficacy was performed against a challenge with L. amazonensis, along with an evaluation of the immune response profile generated in BALB/C mice. The animals were followed for sample processing and quantification of serum-specific cytokines, nitrites and antibodies. The sera of animals immunized with the non-encapsulated antigen formulations showed higher intensities of nitrites and total IgGs. This approach evidenced the importance of the biological studies involving the immune response of the host against the parasite being interconnected and related to the subfractionation of its proteins in the search for more effective vaccine candidates. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Evidence of a drug-specific impact of experimentally selected paromomycin and miltefosine resistance on parasite fitness in Leishmania infantum.

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    Hendrickx, S; Beyers, J; Mondelaers, A; Eberhardt, E; Lachaud, L; Delputte, P; Cos, P; Maes, L

    2016-07-01

    Although miltefosine and paromomycin were only recently introduced to treat visceral leishmaniasis, increasing numbers of miltefosine treatment failures and occasional primary resistance to both drugs have been reported. Understanding alterations in parasite behaviour linked to drug resistance is essential to assess the propensity for emergence and spread of resistant strains, particularly since a positive effect on fitness has been reported for antimony-resistant parasites. This laboratory study compared the fitness of a drug-susceptible parent WT clinical Leishmania infantum isolate (MHOM/FR/96/LEM3323) and derived miltefosine and paromomycin drug-resistant lines that were experimentally selected at the intracellular amastigote level. Parasite fitness of WT, paromomycin-resistant and miltefosine-resistant strains, in vitro and in vivo parasite growth, metacyclogenesis, infectivity and macrophage stress responses were comparatively evaluated. No significant differences in promastigote fitness were noted between the WT and paromomycin-resistant strain, while clear benefits could be demonstrated for paromomycin-resistant amastigotes in terms of enhanced in vitro and in vivo growth potential and intracellular stress response. The miltefosine-resistant phenotype showed incomplete promastigote metacyclogenesis, decreased intracellular growth and weakened stress response, revealing a reduced fitness compared with WT parent parasites. The rapid selection and fitness advantages of paromomycin-resistant amastigotes endorse the current use of paromomycin in combination therapy. Although a reduced fitness of miltefosine-resistant strains may explain the difficulty of miltefosine resistance selection in vitro, the growing number of miltefosine treatment failures in the field still requires further exploratory research. © The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions

  10. Detection and chronology of parasitic kinetoplast DNA presence in hair of experimental Leishmania major infected BALB/c mice by Real Time PCR.

    Science.gov (United States)

    Iniesta, Virginia; Belinchón-Lorenzo, Silvia; Soto, Manuel; Fernández-Cotrina, Javier; Muñoz-Madrid, Rubén; Monroy, Isabel; Baz, Victoria; Gómez-Luque, Adela; Parejo, Juan Carlos; Alonso, Carlos; Nieto, Luis Carlos Gómez

    2013-12-01

    Hair can accumulate foreign chemical or biological substances. Recently, it has been reported that parasite DNA can also be detected in the hair of Leishmania infantum infected dogs. The aim of this work has been to find out whether parasite DNA incorporates in the hair of Leishmania major experimentally infected animals. For this purpose, a group of 4 BALB/c mice, intradermally inoculated in both ears with 1000 L. major V1 strain promastigote forms, was monitored for parameters associated to the infection during 35 days. Weekly, ear swelling was measured, and hair samples from ears and leg were collected. Blood samples were obtained before challenge and at day 35 post infection, when parasite load was measured in ear, lymph node and spleen by limit dilution. Ear swelling and other parameters observed in the infected mice were consistent with those described for this model. The presence of parasite kinetoplast DNA (kDNA) was detected by Real Time PCR in all ear and leg hair samples at the final timepoint. These data suggests that hair is a specialized tissue in the sequestration and removal of foreign DNA. Detection of DNA in hair could be, therefore, a useful tool to chronologically record the infection process during experimental mice assays. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Detection of Leishmania ( Leishmania) amazonensis and Leishmania ( Leishmania) infantum chagasi in Brazilian bats

    National Research Council Canada - National Science Library

    Savani, Elisa San Martin Mouriz; de Almeida, Marilene Fernandes; de Oliveira Camargo, Maria Cecília Gibrail; D’Auria, Sandra Regina Nicoletti; Silva, Miriam Martos Sodré; de Oliveira, Maria Lúcia; Sacramento, Débora

    2010-01-01

    ...) for trypanosomatids. The indirect immunofluorescent antibody test demonstrated that 0.9% of bats react positively for leishmaniosis and PCR detected the presence of DNA of Leishmania (Leishmania...

  12. Vaccination with a novel recombinant Leishmania antigen plus MPL provides partial protection against L. donovani challenge in experimental model of visceral leishmaniasis.

    Science.gov (United States)

    Bhardwaj, Suvercha; Vasishta, R K; Arora, Sunil K

    2009-01-01

    The acquisition of immunity following subclinical or resolved infection with the intracellular parasite Leishmania donovani suggests that vaccination could prevent visceral leishmaniasis. The characteristics and in vitro stimulating capability of the recombinant proteins expressed by previously identified clones on the basis of their capacity to stimulate an indigenously established Leishmania-specific cell line leading to high level of IFN-gamma suggested these to be potential candidates for immunoprophylaxis against leishmaniasis. In this study, we investigated the protective efficacy of purified recombinant proteins from two of the identified cDNA clones along with the adjuvant MPL, in a hamster model of experimental leishmaniasis. We demonstrate here that the immunization of animals with one of the recombinant proteins (rF14) having 97% similarity to C1 clone of L. chagasi ribosomal protein gene P0 (rLiP0) along with MPL provided partial protection against the virulent challenge of L. donovani. The absence of antigen-specific lymphoproliferative responses in these immunized animals may be responsible for the lack of complete and long-lasting protection.

  13. Immunization against leishmaniasis by PLGA nanospheres loaded with an experimental autoclaved Leishmania major (ALM) and Quillaja saponins.

    Science.gov (United States)

    Tafaghodi, M; Eskandari, M; Kharazizadeh, M; Khamesipour, A; Jaafari, M R

    2010-12-01

    Immune responses against the Leishmania antigens are not sufficient to protect against a leishmania challenge. Therefore these antigens need to be potentiated by various adjuvants and delivery systems. In this study, Poly (d,l-lactide-co-glycolide (PLGA) nanospheres as antigen delivery system and Quillaja saponins (QS) as immunoadjuvant have been used to enhance the immune response against autoclaved Leishmania major (ALM). PLGA nanospheres were prepared by a double-emulsion (W/O/W) technique. Particulate characteristics were studied by scanning electron microscopy and particle size analysis. Mean diameter for nanospheres loaded with ALM+QS was 294 ± 106 nm. BALB/c mice were immunized three times in 3-weeks intervals using ALM plus QS loaded nanospheres [(ALM+QS)PLGA], ALM encapsulated with PLGA nanospheres [(ALM)PLGA], (ALM)PLGA + QS, ALM + QS, ALM alone or PBS. The intensity of infection induced by L. major challenge was assessed by measuring size of footpad swelling. The strongest protection, showed by significantly (P < 0.05) smaller footpad, were observed in mice immunized with (ALM)PLGA. The (ALM+QS)PLGA group showed the least protection and highest swelling, while the (ALM)PLGA+QS, ALM+QS and ALM showed an intermediate protection with no significant difference. The mice immunized with ALM and ALM+QS showed the highest IgG2a/IgG1 ratio (P < 0.01), followed by (ALM)PLGA+QS. The highest IFN-γ and lowest IL-4 production was seen in (ALM)PLGA+QS, ALM+QS groups. The highest parasite burden was observed in (ALM)PLGA+QS and (ALM+QS)PLGA groups. It is concluded that PLGA nanospheres as a vaccine delivery system could increase the protective immune responses, but QS adjuvant has a reverse effect on protective immune responses and the least protective responses were seen in the presence of this adjuvant.

  14. Induction of cellular and humoral responses by autoclaved and heat-killed antigen of Leishmania donovani in experimental visceral leishmaniasis.

    Science.gov (United States)

    Nagill, Rajeev; Mahajan, Raman; Sharma, Meenakshi; Kaur, Sukhbir

    2009-12-01

    The potential of autoclaved and heat-killed antigen of Leishmania donovani to induce cell-mediated and humoral response has been evaluated in the present study. The vaccines were delivered thrice subcutaneously at an interval of 2 weeks. Two weeks after second booster, BALB/c mice were challenged with 10(7) stationary phase promastigotes of L. donovani. Significant protection was achieved in immunized mice against L. donovani challenge with 69% to 76% and 59% to 64% reduction in parasite load in the liver and spleen respectively. Immunization induced significantly higher level of delayed type hypersensitivity (DTH) response in mice immunized with heat-killed antigen followed by autoclaved antigen. The immune response was assessed by quantifying Leishmania-specific antibodies and cytokine production. The antibody response was predominantly of IgG type with increased IgG2a production and lesser amount of IgM. The immunization preferentially stimulates the production of IFN-gamma and IL-2 in splenocytes which suggests a Th1 type response with a concomitant down-regulation of IL-10 and IL-4. These results indicate a potential for the heat-killed and autoclaved antigen as a vaccine which could trigger cell-mediated immune response.

  15. Vaccination with the Leishmania major ribosomal proteins plus CpG oligodeoxynucleotides induces protection against experimental cutaneous leishmaniasis in mice.

    Science.gov (United States)

    Iborra, Salvador; Parody, Nuria; Abánades, Daniel R; Bonay, Pedro; Prates, Deboraci; Novais, Fernanda O; Barral-Netto, Manoel; Alonso, Carlos; Soto, Manuel

    2008-01-01

    In the present work we analyze the antigenicity of Leishmania major ribosomal proteins (LRP) in infected BALB/c mice. We show that BALB/c mice vaccinated with LRP in the presence of CpG oligodeoxynucleotides (CpG-ODN) were protected against the development of dermal pathology and showed a reduction in the parasite load after challenge with L. major. This protection was associated with the induction of an IL-12 dependent specific-IFN-gamma response mediated mainly by CD4(+) T cell, albeit a minor contribution of CD8(+) T cells cannot be ruled out. Induction of Th1 responses against LRP also resulted in a reversion of the Th2 responses associated with susceptibility. A marked reduction of IgG1 antibody titer against parasite antigens besides an impaired IL-4 and IL-10 cytokine production by parasite specific T cells was observed. In addition, we show that the administration of the LRP plus CpG-ODN preparation also conferred protection in the naturally resistant C57BL/6 mice. In this strain protection was associated with a LRP specific IFN-gamma production in lymph nodes draining the challenge site. We believe that these evolutionary conserved proteins, combined with adjuvants that favor Th1 responses, may be relevant components of a pan-Leishmania vaccine.

  16. Evaluation of the immunogenicity and protective efficacy of killed Leishmania donovani antigen along with different adjuvants against experimental visceral leishmaniasis.

    Science.gov (United States)

    Thakur, Ankita; Kaur, Harpreet; Kaur, Sukhbir

    2015-08-01

    Visceral leishmaniasis (VL) caused by Leishmania donovani is a life-threatening disease involving uncontrolled parasitization of vital organs. Drugs to treat leishmaniasis have one or more limitations or insufficiencies in the long run. A safe and efficacious vaccine to control this disease is needed. Killed antigens that could be safer as vaccines have shown limited efficacy in clinical trials. Immunogenic enhancement with appropriate adjuvants may thus be required to elicit protective immunity based on antibodies and effector T-cell functions. Therefore, it is essential to search for adjuvant to enhance the immunogenicity of killed vaccines and to induce protection against leishmaniasis. So, the aim of the present study was to compare the effectiveness of four adjuvants, i.e. alum, saponin, monophosphoryl lipid A, cationic liposome in combination with Killed Leishmania donovani (KLD) antigen against murine VL. Animals were immunized subcutaneously thrice at an interval of 2 weeks with a final volume of 100 μl per dose. Challenge infection was given 2 weeks after last booster. Mice were sacrificed 15 days after last immunization and on 30, 60 and 90 post-infection/challenge days. The protective efficacy of vaccines was revealed by significant reduction in parasite burden and enhanced DTH responses in comparison with the infected controls. Immunized animals also generated significant levels of Th1 cytokines and increased production of IgG2a, thus indicating the generation of a protective Th1 response. All the adjuvants imparted significant protection, but liposomal formulation was most effective followed by KLD + MPL-A, KLD + saponin, KLD + alum and KLD antigen.

  17. Therapeutic immunization with radio-attenuated Leishmania parasites through i.m. route revealed protection against the experimental murine visceral leishmaniasis.

    Science.gov (United States)

    Datta, Sanchita; Manna, Madhumita; Khanra, Supriya; Ghosh, Moumita; Bhar, Radhaballav; Chakraborty, Anindita; Roy, Syamal

    2012-07-01

    After our promising results from prophylactic and therapeutic study (i.p. route) with the radio-attenuated Leishmania donovani parasites against experimental murine visceral leishmaniasis, we prompted to check their therapeutic efficacy through i.m route. BALB/c mice were infected with highly virulent L. donovani parasites. After 75 days, mice were treated with gamma (γ)-irradiated parasites. A second therapeutic immunization was given after 15 days of first immunization. The protection against kala-azar was estimated with the reduction of Leishman-Donovan unit from spleen and liver that scored up to 80% and 93%, respectively, while a twofold increase in nitric oxide (NO) and reactive oxygen species (ROS) productions has been observed in the immunized groups of animals. These groups of mice also showed disease regression by skewing Th2 cytokines (IL-10) towards Th1 cytokine (IFN-γ) bias along with the increased generation of NO and ROS, while the infected control group of mice without such treatment surrendered to the disease. Establishment of Th1 ambience in the treated groups has also been supported from the measured antileishmanial antibody IgG subsets (IgG2a and IgG1) with higher anti-soluble Leishmania antigen-specific IgG2a titer. As seen in our previous studies, doses of attenuation by γ-radiation should be taken into serious consideration. Attenuation of parasites at 50 Gy of absorbed dose of gamma rays has not worked well. Thus, therapeutic use of L. donovani parasites radio-attenuated at particular doses can be exploited as a promising vaccine agent. Absence of any adjuvant may increase its acceptability as vaccine candidate further.

  18. Leishmaniose cutânea experimental: II - aspectos evolutivos da infecção no primata Cebus apella (Cebidae pela Leishmania (V. Braziliensis e L. (L. Amazonensis

    Directory of Open Access Journals (Sweden)

    Fernando T. Silveira

    1990-03-01

    Full Text Available Objetivando avaliar o potencial do primata C. apella como modelo experimental da leishmaniose cutânea, produzida pela L. (V. braziliensis e L. (L. Amazonensis , inocularam-se, via intradérmica, 3 X 10(6 de promastigotas dessas leishmanias, em 8 sítios da cauda de 10 espécimens desse primata, 5 deles com a L. (V. braziliensis e outros 5 com a L. (L. Amazonensis . Posteriormente, às inoculações, o exame semanal dos animais e biópsias mensais, revelaram os seguintes resultados relativos a cada parasita: a L. (V. braziliensis : o período de incubação foi de 15-20 dias; aos 30 dias evidenciaram-se lesões pápulo-eritematosas, que evoluíram para nódulos ao fim de 60 dias; no 3.° mês, notou-se ulceração espontânea destas lesões e, no 4° mês, deu-se o início da reparação das lesões ulceradas, culminando com a cura em um dos animais após 5 meses, em dois após 6 meses, noutro após 7 meses e, no último, após 10 meses. Quanto ao parasitismo nas lesões, foi demonstrado nos 5 animais, até 90 dias; depois disto, somente em 2 até 120 dias e, por fim, até 180 dias apenas naquele que curou depois de 10 meses, b L. (L. Amazonensis : o período de incubação foi de 20 dias; aos 30 dias notou- se lesões pápulo-eritematosas, que também evoluíram para nódulos ao fim de 60 dias, porém, a partir do 3.° mês, estas lesões regrediram rapidamente ao fim de 90 dias, quando não mais detectou-se o parasita na pele dos animais. Em relação aos testes de Montenegro, somente 2 dos 5 animais infectados com a L. (V. braziliensis reagiram ao teste, 60 e 90 dias após as inoculações. Os resultados observados permitiram confirmar a infectividade do C. apella a estas leishmanias e, também, reforçar a indicação desse primata como modelo experimental da leishmaniose cutânea causada por estes parasitas.

  19. Evaluation of Live Recombinant Nonpathogenic Leishmania tarentolae Expressing Cysteine Proteinase and A2 Genes as a Candidate Vaccine against Experimental Canine Visceral Leishmaniasis

    Science.gov (United States)

    Shahbazi, Mehdi; Zahedifard, Farnaz; Taheri, Tahereh; Taslimi, Yasaman; Jamshidi, Shahram; Shirian, Sadegh; Mahdavi, Niousha; Hassankhani, Mehdi; Daneshbod, Yahya; Zarkesh-Esfahani, Sayyed Hamid; Papadopoulou, Barbara; Rafati, Sima

    2015-01-01

    Canine Visceral Leishmaniasis (CVL) is a major veterinary and public health problem caused by Leishmania infantum (L. infantum) in many endemic countries. It is a severe chronic disease with generalized parasite spread to the reticuloendothelial system, such as spleen, liver and bone marrow and is often fatal when left untreated. Control of VL in dogs would dramatically decrease infection pressure of L. infantum for humans, since dogs are the main domestic reservoir. In the past decade, various subunits and DNA antigens have been identified as potential vaccine candidates in experimental animal models, but none has been approved for human use so far. In this study, we vaccinated outbreed dogs with a prime-boost regimen based on recombinant L. tarentolae expressing the L. donovani A2 antigen along with cysteine proteinase genes (CPA and CPB without its unusual C-terminal extension (CPB-CTE) and evaluated its immunogenicity and protective immunity against L. infantum infectious challenge. We showed that vaccinated animals produced significantly higher levels of IgG2, but not IgG1, and also IFN-γ and TNF-α, but low IL-10 levels, before and after challenge as compared to control animals. Protection in dogs was also correlated with a strong DTH response and low parasite burden in the vaccinated group. Altogether, immunization with recombinant L. tarentolae A2-CPA-CPB-CTE was proven to be immunogenic and induced partial protection in dogs, hence representing a promising live vaccine candidate against CVL. PMID:26197085

  20. Evaluation of Live Recombinant Nonpathogenic Leishmania tarentolae Expressing Cysteine Proteinase and A2 Genes as a Candidate Vaccine against Experimental Canine Visceral Leishmaniasis.

    Science.gov (United States)

    Shahbazi, Mehdi; Zahedifard, Farnaz; Taheri, Tahereh; Taslimi, Yasaman; Jamshidi, Shahram; Shirian, Sadegh; Mahdavi, Niousha; Hassankhani, Mehdi; Daneshbod, Yahya; Zarkesh-Esfahani, Sayyed Hamid; Papadopoulou, Barbara; Rafati, Sima

    2015-01-01

    Canine Visceral Leishmaniasis (CVL) is a major veterinary and public health problem caused by Leishmania infantum (L. infantum) in many endemic countries. It is a severe chronic disease with generalized parasite spread to the reticuloendothelial system, such as spleen, liver and bone marrow and is often fatal when left untreated. Control of VL in dogs would dramatically decrease infection pressure of L. infantum for humans, since dogs are the main domestic reservoir. In the past decade, various subunits and DNA antigens have been identified as potential vaccine candidates in experimental animal models, but none has been approved for human use so far. In this study, we vaccinated outbreed dogs with a prime-boost regimen based on recombinant L. tarentolae expressing the L. donovani A2 antigen along with cysteine proteinase genes (CPA and CPB without its unusual C-terminal extension (CPB-CTE) and evaluated its immunogenicity and protective immunity against L. infantum infectious challenge. We showed that vaccinated animals produced significantly higher levels of IgG2, but not IgG1, and also IFN-γ and TNF-α, but low IL-10 levels, before and after challenge as compared to control animals. Protection in dogs was also correlated with a strong DTH response and low parasite burden in the vaccinated group. Altogether, immunization with recombinant L. tarentolae A2-CPA-CPB-CTE was proven to be immunogenic and induced partial protection in dogs, hence representing a promising live vaccine candidate against CVL.

  1. Evaluation of Live Recombinant Nonpathogenic Leishmania tarentolae Expressing Cysteine Proteinase and A2 Genes as a Candidate Vaccine against Experimental Canine Visceral Leishmaniasis.

    Directory of Open Access Journals (Sweden)

    Mehdi Shahbazi

    Full Text Available Canine Visceral Leishmaniasis (CVL is a major veterinary and public health problem caused by Leishmania infantum (L. infantum in many endemic countries. It is a severe chronic disease with generalized parasite spread to the reticuloendothelial system, such as spleen, liver and bone marrow and is often fatal when left untreated. Control of VL in dogs would dramatically decrease infection pressure of L. infantum for humans, since dogs are the main domestic reservoir. In the past decade, various subunits and DNA antigens have been identified as potential vaccine candidates in experimental animal models, but none has been approved for human use so far. In this study, we vaccinated outbreed dogs with a prime-boost regimen based on recombinant L. tarentolae expressing the L. donovani A2 antigen along with cysteine proteinase genes (CPA and CPB without its unusual C-terminal extension (CPB-CTE and evaluated its immunogenicity and protective immunity against L. infantum infectious challenge. We showed that vaccinated animals produced significantly higher levels of IgG2, but not IgG1, and also IFN-γ and TNF-α, but low IL-10 levels, before and after challenge as compared to control animals. Protection in dogs was also correlated with a strong DTH response and low parasite burden in the vaccinated group. Altogether, immunization with recombinant L. tarentolae A2-CPA-CPB-CTE was proven to be immunogenic and induced partial protection in dogs, hence representing a promising live vaccine candidate against CVL.

  2. Leishmania donovani

    Science.gov (United States)

    Barbosa Santos, Micheli Luize; Nico, Dirlei; de Oliveira, Fabrícia Alvisi; Barreto, Aline Silva; Palatnik-de-Sousa, Iam; Carrillo, Eugenia; Moreno, Javier; de Luca, Paula Mello; Morrot, Alexandre; Rosa, Daniela Santoro; Palatnik, Marcos; Bani-Corrêa, Cristiane; de Almeida, Roque Pacheco; Palatnik-de-Sousa, Clarisa Beatriz

    2017-01-01

    Development of immunoprotection against visceral leishmaniasis (VL) focused on the identification of antigens capable of inducing a Th1 immune response. Alternatively, antigens targeting the CD8 and T-regulatory responses are also relevant in VL pathogenesis and worthy of being included in a preventive human vaccine. We assessed in active and cured patients and VL asymptomatic subjects the clinical signs and cytokine responses to the Leishmania donovani nucleoside hydrolase NH36 antigen and its N-(F1), central (F2) and C-terminal (F3) domains. As markers of VL resistance, the F2 induced the highest levels of IFN-γ, IL-1β, and TNF-α and, together with F1, the strongest secretion of IL-17, IL-6, and IL-10 in DTH + and cured subjects. F2 also promoted the highest frequencies of CD3 + CD4 + IL-2 + TNF-α - IFN-γ - , CD3 + CD4 + IL-2 + TNF-α + IFN-γ - , CD3 + CD4 + IL-2 + TNF-α - IFN-γ + , and CD3 + CD4 + IL-2 + TNF-α + IFN-γ + T cells in cured and asymptomatic subjects. Consistent with this, the IFN-γ increase was correlated with decreased spleen ( R  = -0.428, P  = 0.05) and liver sizes ( R  = -0.428, P  = 0.05) and with increased hematocrit counts ( R  = 0.532, P  = 0.015) in response to F1 domain, and with increased hematocrit ( R  = 0.512, P 0.02) and hemoglobin counts ( R  = 0.434, P  = 0.05) in response to F2. Additionally, IL-17 increases were associated with decreased spleen and liver sizes in response to F1 ( R  = -0.595, P  = 0.005) and F2 ( R  = -0.462, P  = 0.04). Conversely, F1 and F3 increased the CD3 + CD8 + IL-2 + TNF-α - IFN-γ - , CD3 + CD8 + IL-2 + TNF-α + IFN-γ - , and CD3 + CD8 + IL-2 + TNF-α + IFN-γ + T cell frequencies of VL patients correlated with increased spleen and liver sizes and decreased hemoglobin and hematocrit values. Therefore, cure and acquired resistance to VL correlate with the CD4 + -Th1 and Th-17 T-cell responses to F2 and F1 domains. Clinical VL outcomes, by

  3. Cell migration induced by Leishmania (Leishmania) amazonensis, Leishmania (Leishmania) major and Leishmania (Viannia) braziliensis into the peritoneal cavity of BALB/c mice

    OpenAIRE

    DT Wakimoto; KV Gaspareto; TGV Silveira; MVC Lonardoni; SMA Aristides

    2010-01-01

    In American cutaneous leishmaniasis, the initial infection phase is characterized by recruitment of neutrophils and monocytes. The migration of these cells in response to the presence of Leishmania in the peritoneum of affected animals remains unclear. The objective of this study was to investigate cell migration to the peritoneum of BALB/c mice after infection with Leishmania (Leishmania) amazonensis, Leishmania (Viannia) braziliensis and Leishmania (Leishmania) major. Initially, Leishmania ...

  4. Functional complexity of the Leishmania granuloma and the potential of in silico modelling

    Directory of Open Access Journals (Sweden)

    John eMoore

    2013-02-01

    Full Text Available AbstractIn human and canine visceral leishmaniasis and in various experimental models of this disease, host resistance is strongly linked to efficient granuloma development. However, it is unknown exactly how the granuloma microenvironment executes an effective antileishmanial response. Recent studies, including using advanced imaging techniques have improved our understanding of granuloma biology, at the cellular level, highlighting heterogeneity in granuloma development and function, and hinting at complex cellular, temporal and spatial dynamics. In this mini-review, we discuss the factors involved in the formation and function of L.donovani-induced hepatic granulomas, as well as their importance in protecting against inflammation-associated tissue damage and the generation of immunity to rechallenge. Finally, we discuss the role that computational, agent-based models may play to answer outstanding questions within the field.

  5. Efficacy of Leishmania donovani trypanothione reductase, identified as a potent Th1 stimulatory protein, for its immunogenicity and prophylactic potential against experimental visceral leishmaniasis.

    Science.gov (United States)

    Khare, Prashant; Jaiswal, Anil Kumar; Tripathi, Chandra Dev Pati; Joshi, Sumit; Sundar, Shyam; Dube, Anuradha

    2014-03-01

    In visceral leishmaniasis (VL), Th1-type of immune responses play an important role which correlates with recovery from and resistance to disease resulting in lifelong immunity. Based on this rationale, the soluble leishmanial antigens that elicit cellular responses in peripheral blood mononuclear cells (PBMCs) from cured Leishmania patients were characterized through immunoproteomic approach which led to the identification of trypanothione reductase (TPR) (a cytosolic enzyme explored as a drug target), as one of the potent Th1 stimulatory protein. In this study, the immunogenicity of recombinant Leishmania donovani TPR (rLdTPR) was assessed in PBMCs of cured Leishmania-infected patients/hamsters and further evaluated its prophylactic efficacy against L. donovani challenges in hamsters. Substantial proliferative responses to rLdTPR, as compared to soluble L. donovani antigen, were observed in Leishmania-infected cured patients as well as in hamsters. Moreover, rLdTPR reasonably stimulated PBMCs of cured Leishmania patients to produce IFNγ, IL-12, and TNF-α but not IL-4 or IL-10. On the other hand, the protein downregulated LPS-induced IL-10 as well as soluble L. donovani antigen-induced IL-4 production in PBMCs of Leishmania patients. In case of cured hamsters, rLdTPR generates mixed Th1 and Th2 immune response. Vaccination with rLdTPR along with Bacillus Calmette-Guerin (BCG) was able to provide considerably good prophylactic efficacy (~60%) against L. donovani challenge in hamsters. The efficacy was supported by the increased inducible NO synthase mRNA transcript and Th1-type cytokines IFNγ, IL-12, and TNF-α and downregulation of IL-4, IL-10, and TGF-β. Since rLdTPR protein is an important target, further attempts towards determination of immunodominant regions for designing fusion peptides may be taken up to optimize its prophylactic efficacy.

  6. Cytokine and nitric oxide patterns in dogs immunized with LBSap vaccine, before and after experimental challenge with Leishmania chagasi plus saliva of Lutzomyia longipalpis.

    Science.gov (United States)

    Resende, Lucilene Aparecida; Roatt, Bruno Mendes; Aguiar-Soares, Rodrigo Dian de Oliveira; Viana, Kelvinson Fernandes; Mendonça, Ludmila Zanandreis; Lanna, Mariana Ferreira; Silveira-Lemos, Denise; Corrêa-Oliveira, Rodrigo; Martins-Filho, Olindo Assis; Fujiwara, Ricardo Toshio; Carneiro, Cláudia Martins; Reis, Alexandre Barbosa; Giunchetti, Rodolfo Cordeiro

    2013-12-06

    In the studies presented here, dogs were vaccinated against Leishmania (Leishmania) chagasi challenge infection using a preparation of Leishmania braziliensis promastigote proteins and saponin as adjuvant (LBSap). Vaccination with LBSap induced a prominent type 1 immune response that was characterized by increased levels of interleukin (IL-) 12 and interferon gamma (IFN-γ) production by peripheral blood mononuclear cells (PBMC) upon stimulation with soluble vaccine antigen. Importantly, results showed that this type of responsiveness was sustained after challenge infection; at day 90 and 885 after L. chagasi challenge infection, PBMCs from LBSap vaccinated dogs produced more IL-12, IFN-γ and concomitant nitric oxide (NO) when stimulated with Leishmania antigens as compared to PBMCs from respective control groups (saponin, LB- treated, or non-treated control dogs). Moreover, transforming growth factor (TGF)-β decreased in the supernatant of SLcA-stimulated PBMCs in the LBSap group at 90 days. Bone marrow parasitological analysis revealed decreased frequency of parasitism in the presence of vaccine antigen. It is concluded that vaccination of dogs with LBSap vaccine induced a long-lasting type 1 immune response against L. chagasi challenge infection. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  7. Immunization with the DNA-encoding N-terminal domain of proteophosphoglycan of Leishmania donovani generates Th1-type immunoprotective response against experimental visceral leishmaniasis.

    Science.gov (United States)

    Samant, Mukesh; Gupta, Reema; Kumari, Shraddha; Misra, Pragya; Khare, Prashant; Kushawaha, Pramod Kumar; Sahasrabuddhe, Amogh Anant; Dube, Anuradha

    2009-07-01

    Leishmania produce several types of mucin-like glycoproteins called proteophosphoglycans (PPGs) which exist as secretory as well as surface-bound forms in both promastigotes and amastigotes. The structure and function of PPGs have been reported to be species and stage specific as in the case of Leishmania major and Leishmania mexicana; there has been no such information available for Leishmania donovani. We have recently demonstrated that PPG is differentially expressed in sodium stibogluconate-sensitive and -resistant clinical isolates of L. donovani. To further elucidate the structure and function of the ppg gene of L. donovani, a partial sequence of its N-terminal domain of 1.6 kb containing the majority of antigenic determinants, was successfully cloned and expressed in prokaryotic as well as mammalian cells. We further evaluated the DNA-encoding N-terminal domain of the ppg gene as a vaccine in golden hamsters (Mesocricetus auratus) against the L. donovani challenge. The prophylactic efficacy to the tune of approximately 80% was observed in vaccinated hamsters and all of them could survive beyond 6 mo after challenge. The efficacy was supported by a surge in inducible NO synthase, IFN-gamma, TNF-alpha, and IL-12 mRNA levels along with extreme down-regulation of TGF-beta, IL-4, and IL-10. A rise in the level of Leishmania-specific IgG2 was also observed which was indicative of enhanced cellular immune response. The results suggest the N-terminal domain of L. donovani ppg as a potential DNA vaccine against visceral leishmaniasis.

  8. Genomic and Molecular Characterization of Miltefosine Resistance in Leishmania infantum Strains with Either Natural or Acquired Resistance through Experimental Selection of Intracellular Amastigotes.

    Science.gov (United States)

    Mondelaers, Annelies; Sanchez-Cañete, Maria P; Hendrickx, Sarah; Eberhardt, Eline; Garcia-Hernandez, Raquel; Lachaud, Laurence; Cotton, James; Sanders, Mandy; Cuypers, Bart; Imamura, Hideo; Dujardin, Jean-Claude; Delputte, Peter; Cos, Paul; Caljon, Guy; Gamarro, Francisco; Castanys, Santiago; Maes, Louis

    2016-01-01

    During the last decade miltefosine (MIL) has been used as first-line treatment for visceral leishmaniasis in endemic areas with antimonial resistance, but a decline in clinical effectiveness is now being reported. While only two MIL-resistant Leishmania infantum strains from HIV co-infected patients have been documented, phenotypic MIL-resistance for L. donovani has not yet been identified in the laboratory. Hence, a better understanding of the factors contributing to increased MIL-treatment failure is necessary. Given the paucity of defined MIL-resistant L. donovani clinical isolates, this study used an experimental amastigote-selected MIL-resistant L. infantum isolate (LEM3323). In-depth exploration of the MIL-resistant phenotype was performed by coupling genomic with phenotypic data to gain insight into gene function and the mutant phenotype. A naturally MIL-resistant L. infantum clinical isolate (LEM5159) was included to compare both datasets. Phenotypically, resistance was evaluated by determining intracellular amastigote susceptibility in vitro and actual MIL-uptake. Genomic analysis provided supportive evidence that the resistance selection model on intracellular amastigotes can be a good proxy for the in vivo field situation since both resistant strains showed mutations in the same inward transporter system responsible for the acquired MIL-resistant phenotype. In line with previous literature findings in promastigotes, our data confirm a defective import machinery through inactivation of the LiMT/LiRos3 protein complex as the main mechanism for MIL-resistance also in intracellular amastigotes. Whole genome sequencing analysis of LEM3323 revealed a 2 base pair deletion in the LiMT gene that led to the formation an early stop codon and a truncation of the LiMT protein. Interestingly, LEM5159 revealed mutations in both the LiMT and LiRos3 genes, resulting in an aberrant expression of the LiMT protein. To verify that these mutations were indeed accountable for

  9. Innate Immunity to Leishmania Infection: Within Phagocytes

    Directory of Open Access Journals (Sweden)

    Marcela Freitas Lopes

    2014-01-01

    Full Text Available Infection by Leishmania takes place in the context of inflammation and tissue repair. Besides tissue resident macrophages, inflammatory macrophages and neutrophils are recruited to the infection site and serve both as host cells and as effectors against infection. Recent studies suggest additional important roles for monocytes and dendritic cells. This paper addresses recent experimental findings regarding the regulation of Leishmania major infection by these major phagocyte populations. In addition, the role of IL-4 on dendritic cells and monocytes is discussed.

  10. Effect of Bixa orellana against Leishmania amazonensis.

    Science.gov (United States)

    García, Marley; Monzote, Lianet; Montalvo, Ana M; Scull, Ramón

    2011-01-01

    In the present study, an activity of Bixa orellana extract against Leishmania amazonensis was demonstrated. Experimentally infected BALB/c mice were treated with B. orellana extract which showed a significant activity against promastigote and amastigote forms of L. amazonensis. This study supports the importance of natural sources as antileishmanial drugs. Copyright © 2011 S. Karger AG, Basel.

  11. PCR para la confirmación de transmisión experimental de Leishmania chagasi a hámster sano por picadura de Lutzomyia longipalpis (Diptera: Psychodidae.

    Directory of Open Access Journals (Sweden)

    Olga L. Cabrera

    2003-06-01

    Full Text Available Se evaluó la efectividad de la PCR como herramienta en la detección de la transmisión experimental de Leishmania chagasi a hámster, Mesocricetus auratus, por picadura del insecto vector. Dos pares de hámsteres sanos y anestesiados fueron colocados en jaulas que contenían hembras de Lutzomyia longipalpis. Previamente, las hembras se infectaron experimentalmente con Leishmania chagasi y la infección se confirmó por disección en una submuestra. A los 37 y 51 días después de la exposición a los insectos infectados, las biopsias de hígado y bazo de cada hámster se sometieron a examen directo al microscopio, histopatología y PCR. El ADN se extrajo con Chelex 100®; en la amplificación se utilizó un par de iniciadores específicos para la región conservada de los minicírculos del ADN de Leishmania. El producto amplificado se separó en geles de agarosa y se visualizó bajo luz UV. En tres de las cuatro biopsias se observó una banda de 120 pares de bases, aproximadamente, correspondiente al tamaño esperado de la fracción del minicírculo. La técnica de PCR fue el único método que detectó la presencia del parásito. Estos resultados demostraron que la sensibilidad de la PCR acelera los procesos de incriminación vectorial de las especies vectoras de leishmaniasis.

  12. The immunobiology of Leishmania braziliensis infection.

    Science.gov (United States)

    de Oliveira, Camila I; Brodskyn, Claudia I

    2012-01-01

    Leishmaniases are a group of diseases caused by protozoa of the genus Leishmania that affect millions of people worldwide. These diseases are caused by distinct Leishmania species, of which L. braziliensis, a New World representative of the Leishmania genus, has been the least studied. Although leishmaniasis caused by L. braziliensis induces a range of clinical manifestations ranging from mild localized lesions to severe mucosal involvement, few studies have focused on elucidating the immune mechanisms behind this pathology. In this review, we focus on the immunobiology of L. braziliensis infection, emphasizing the innate and adaptive immune responses and taking into consideration both studies performed in endemic areas and experimental models of infection. Additionally, we address recent findings regarding the role of sand fly saliva in disease immunopathogenesis and vaccine development.

  13. The immunobiology of Leishmania braziliensis infection

    Directory of Open Access Journals (Sweden)

    Claudia Ida Brodskyn

    2012-06-01

    Full Text Available Leishmaniases are a group of diseases caused by protozoa of the genus Leishmania that affect millions of people worldwide. These diseases are caused by distinct Leishmania species, of which L. braziliensis, a New World representative of the Leishmania genus, has been the least studied. Although leishmaniasis caused by L. braziliensis induces a range of clinical manifestations ranging from mild localized lesions to severe mucosal involvement, few studies have focused on elucidating the immune mechanisms behind this pathology. In this review, we focus on the immunobiology of L. braziliensis infection, emphasizing the innate and adaptive immune responses and taking into consideration both studies performed in endemic areas and experimental models of infection. Additionally, we address recent findings regarding the role of sand fly saliva in disease immunopathogenesis and vaccine development.

  14. Palaearctic origin of Leishmania

    Directory of Open Access Journals (Sweden)

    Sara F Kerr

    2000-01-01

    Full Text Available The hypothesis of a Palaearctic origin of Leishmania in the early Cenozoic, dispersal to the Nearctic in the late Eocene and to the Neotropical in the Pliocene is presented. It is further hypothesized that murid rodents and their immediate ancestors have been important mammalian reservoirs since the origination of Leishmania. Biochemical, molecular, biogeographical, entomological, mammalalogical and ecological support for these hypotheses are reviewed.

  15. [Immunopathogenesis of Leishmania infections].

    Science.gov (United States)

    Yurdakul, Pinar

    2005-07-01

    Leishmaniasis represents a complex of diseases with a clinical and epidemiological diversity. Leishmaniasis remains a severe public health problem and its burden is increasing. The disease is caused by a parasite belonging to the genus Leishmania. Approximately 350 billion people in 88 different countries are thought to be infected with Leishmania spp. Clinical forms of leishmaniasis are particularly diverse representing different diseases: visceral (VL), cutaneous (CL), diffuse cutaneous (DCL) and muco-cutaneous (MCL) leishmaniasis. Being the most important determinant not only cellular immunity plays the essential role in the control of leishmaniasis, but the virulence, tropism and pathogenicity that is modulated by environmental and genetic factors of their mammalian hosts and sandfly vectors, are the key interactions. These eukaryotic pathogens have evolved with the vertebrate immune system and typically produce long lasting chronic infections. A critical step in their host interaction is the evasion of innate immune defenses. The ability to avoid attack by humoral effector mechanisms, such as complement lysis, and to resist killing by lysosomal enzymes and toxic metabolytes is of particular importance. They do so by remodelling the phagosomal compartments in which they reside and by interfering with signalling pathways that lead to cellular activation. In addition they modify the antigen presenting and immunoregulatory functions of dendritic cells, a process that fascilitates their evasion of both innate and adaptive immunity. Experimental animal studies revealed that these modifications and interference mechanisms led to two different pathogenesis schemes. For CL, the polarization of Th2/Th1 cells is responsible for the progression of the disease which than leads to the chronic-persistant state. The Th2/Th1 paradigm does not apply for visceral leishmaniasis. Immunosupression rather than polarization is responsible for the systemic and progressive outcome of

  16. Genomic and Molecular Characterization of Miltefosine Resistance in Leishmania infantum Strains with Either Natural or Acquired Resistance through Experimental Selection of Intracellular Amastigotes

    Science.gov (United States)

    Hendrickx, Sarah; Eberhardt, Eline; Garcia-Hernandez, Raquel; Lachaud, Laurence; Cotton, James; Sanders, Mandy; Cuypers, Bart; Imamura, Hideo; Dujardin, Jean-Claude; Delputte, Peter; Cos, Paul; Caljon, Guy; Gamarro, Francisco; Castanys, Santiago

    2016-01-01

    During the last decade miltefosine (MIL) has been used as first-line treatment for visceral leishmaniasis in endemic areas with antimonial resistance, but a decline in clinical effectiveness is now being reported. While only two MIL-resistant Leishmania infantum strains from HIV co-infected patients have been documented, phenotypic MIL-resistance for L. donovani has not yet been identified in the laboratory. Hence, a better understanding of the factors contributing to increased MIL-treatment failure is necessary. Given the paucity of defined MIL-resistant L. donovani clinical isolates, this study used an experimental amastigote-selected MIL-resistant L. infantum isolate (LEM3323). In-depth exploration of the MIL-resistant phenotype was performed by coupling genomic with phenotypic data to gain insight into gene function and the mutant phenotype. A naturally MIL-resistant L. infantum clinical isolate (LEM5159) was included to compare both datasets. Phenotypically, resistance was evaluated by determining intracellular amastigote susceptibility in vitro and actual MIL-uptake. Genomic analysis provided supportive evidence that the resistance selection model on intracellular amastigotes can be a good proxy for the in vivo field situation since both resistant strains showed mutations in the same inward transporter system responsible for the acquired MIL-resistant phenotype. In line with previous literature findings in promastigotes, our data confirm a defective import machinery through inactivation of the LiMT/LiRos3 protein complex as the main mechanism for MIL-resistance also in intracellular amastigotes. Whole genome sequencing analysis of LEM3323 revealed a 2 base pair deletion in the LiMT gene that led to the formation an early stop codon and a truncation of the LiMT protein. Interestingly, LEM5159 revealed mutations in both the LiMT and LiRos3 genes, resulting in an aberrant expression of the LiMT protein. To verify that these mutations were indeed accountable for

  17. Genomic and Molecular Characterization of Miltefosine Resistance in Leishmania infantum Strains with Either Natural or Acquired Resistance through Experimental Selection of Intracellular Amastigotes.

    Directory of Open Access Journals (Sweden)

    Annelies Mondelaers

    Full Text Available During the last decade miltefosine (MIL has been used as first-line treatment for visceral leishmaniasis in endemic areas with antimonial resistance, but a decline in clinical effectiveness is now being reported. While only two MIL-resistant Leishmania infantum strains from HIV co-infected patients have been documented, phenotypic MIL-resistance for L. donovani has not yet been identified in the laboratory. Hence, a better understanding of the factors contributing to increased MIL-treatment failure is necessary. Given the paucity of defined MIL-resistant L. donovani clinical isolates, this study used an experimental amastigote-selected MIL-resistant L. infantum isolate (LEM3323. In-depth exploration of the MIL-resistant phenotype was performed by coupling genomic with phenotypic data to gain insight into gene function and the mutant phenotype. A naturally MIL-resistant L. infantum clinical isolate (LEM5159 was included to compare both datasets. Phenotypically, resistance was evaluated by determining intracellular amastigote susceptibility in vitro and actual MIL-uptake. Genomic analysis provided supportive evidence that the resistance selection model on intracellular amastigotes can be a good proxy for the in vivo field situation since both resistant strains showed mutations in the same inward transporter system responsible for the acquired MIL-resistant phenotype. In line with previous literature findings in promastigotes, our data confirm a defective import machinery through inactivation of the LiMT/LiRos3 protein complex as the main mechanism for MIL-resistance also in intracellular amastigotes. Whole genome sequencing analysis of LEM3323 revealed a 2 base pair deletion in the LiMT gene that led to the formation an early stop codon and a truncation of the LiMT protein. Interestingly, LEM5159 revealed mutations in both the LiMT and LiRos3 genes, resulting in an aberrant expression of the LiMT protein. To verify that these mutations were indeed

  18. Evaluation of a pan-Leishmania Spliced-Leader RNA Detection Method in Human Blood and Experimentally-Infected Syrian Golden Hamsters.

    Science.gov (United States)

    Eberhardt, Eline; Van den Kerkhof, Magali; Bulté, Dimitri; Mabille, Dorien; Van Bockstal, Lieselotte; Monnerat, Séverine; Alves, Fabiana; Mbui, Jane; Delputte, Peter; Cos, Paul; Hendrickx, Sarah; Maes, Louis; Caljon, Guy

    2018-01-17

    Several methods have been developed for the detection of Leishmania, mostly targeting the minicircle kinetoplast DNA (kDNA). A new RNA qPCR assay was developed targeting the conserved and highly expressed spliced-leader (SL) mini-exon sequence. This study compared the limits of detection of various real-time PCR assays in hamsters infected with Leishmania infantum, in spiked human blood and in clinical blood samples from visceral leishmaniasis patients. The SL-RNA assay showed an excellent analytical sensitivity in tissues (0.005 and 0.002 parasites per mg liver and spleen, respectively) and was not prone to false-positive reactions. Evaluation of the SL-RNA assay on clinical samples demonstrated lower cT-values than the kDNA qPCR, an excellent interrun stability of 97% and a 93% agreement with the kDNA assay, and an estimated sensitivity, specificity, and accuracy of respectively 93.2%, 94.3%, and 93.8%. The SL-RNA qPCR assay was equally efficient to detect L. major, L. tropica, L. mexicana, L. guayensis, L. panamensis, L. braziliensis, L. infantum, and L. donovani and revealed similar SL-RNA levels in the different species and the occurrence of polycistronic SL-containing transcripts in Viannia species. Collectively, this single SL-RNA qPCR assay enables universal Leishmania detection and represents a particularly useful addition to the widely used kDNA assay in clinical studies in which the detection of viable parasites is pivotal to assess parasitological cure. Copyright © 2018. Published by Elsevier Inc.

  19. Gluconeogenesis in Leishmania mexicana

    Science.gov (United States)

    Rodriguez-Contreras, Dayana; Hamilton, Nicklas

    2014-01-01

    Gluconeogenesis is an active pathway in Leishmania amastigotes and is essential for their survival within the mammalian cells. However, our knowledge about this pathway in trypanosomatids is very limited. We investigated the role of glycerol kinase (GK), phosphoenolpyruvate carboxykinase (PEPCK), and pyruvate phosphate dikinase (PPDK) in gluconeogenesis by generating the respective Leishmania mexicana Δgk, Δpepck, and Δppdk null mutants. Our results demonstrated that indeed GK, PEPCK, and PPDK are key players in the gluconeogenesis pathway in Leishmania, although stage-specific differences in their contribution to this pathway were found. GK participates in the entry of glycerol in promastigotes and amastigotes; PEPCK participates in the entry of aspartate in promastigotes, and PPDK is involved in the entry of alanine in amastigotes. Furthermore, the majority of alanine enters into the pathway via decarboxylation of pyruvate in promastigotes, whereas pathway redundancy is suggested for the entry of aspartate in amastigotes. Interestingly, we also found that l-lactate, an abundant glucogenic precursor in mammals, was used by Leishmania amastigotes to synthesize mannogen, entering the pathway through PPDK. On the basis of these new results, we propose a revision in the current model of gluconeogenesis in Leishmania, emphasizing the differences between amastigotes and promastigotes. This work underlines the importance of studying the trypanosomatid intracellular life cycle stages to gain a better understanding of the pathologies caused in humans. PMID:25288791

  20. A novel recombinant Leishmania donovani p45, a partial coding region of methionine aminopeptidase, generates protective immunity by inducing a Th1 stimulatory response against experimental visceral leishmaniasis.

    Science.gov (United States)

    Gupta, Reema; Kushawaha, Pramod K; Tripathi, Chandra Dev Pati; Sundar, Shyam; Dube, Anuradha

    2012-05-01

    The development of a vaccine against visceral leishmaniasis (VL) conferring long-lasting immunity remains a challenge. Identification and proteomic characterization of parasite proteins led to the detection of p45, a member of the methionine aminopeptidase family. To our knowledge the present study is the first known report that describes the molecular and immunological characterization of p45. Recombinant Leishmania donovani p45 (rLdp45) induced cellular responses in cured hamsters and generated Th1-type cytokines from peripheral blood mononuclear cells of cured/endemic VL patients. Immunization with rLdp45 exerted considerable prophylactic efficacy (∼85%) supported by an increase in mRNA expression of iNOS, IFN-γ, TNF-α and IL-12 and decrease in TGF-β and IL-4, indicating its potential as a vaccine candidate against VL. Copyright © 2012. Published by Elsevier Ltd.

  1. Tumor suppressor p53 induces apoptosis of host lymphocytes experimentally infected by Leishmania major, by activation of Bax and caspase-3: a possible survival mechanism for the parasite.

    Science.gov (United States)

    Moshrefi, Mozhgan; Spotin, Adel; Kafil, Hossein Samadi; Mahami-Oskouei, Mahmoud; Baradaran, Behzad; Ahmadpour, Ehsan; Mansoori, Behzad

    2017-08-01

    Apoptosis of infected host macrophages by Leishmania spp. is mainly addressed as one of the survival mechanisms of the parasite. However, there is no eligible data about whether tumor suppressor p53 could induce the apoptosis of host lymphocytes-treated Leishmania major via the mitochondrial intrinsic pathway. In this study, the amastigotes of L. major obtained from ten cutaneous leishmaniases (CL) patients were separately isolated and cultured in N.N.N and RPMI 1640 media. L. major was definitely confirmed by targeting Cyt b gene following sequencing. Subsequently, 2-3 × 106 lymphocytes obtained from ten healthy individuals were isolated and co-cultured with 1-2 × 106 L. major promastigotes. Following 6 h of exposure time, the enzymatic activity of caspase-3 was determined by fluorometric assay in each L. major-treated lymphocytes and cell control (only lymphocyte). The mRNA expressions of Bax, Bcl-2, p53, and caspase-3 genes were assessed by quantitative real-time-PCR analysis following 6 to 9 h of exposure times. The Bcl-2 mRNA expression in L. major-treated lymphocytes was 100-fold down-regulated relative to cell control. The mRNA expressions of p53 and caspase-3 were over-expressed 1.8- and 3.2-fold up-regulated relative to control lymphocytes, respectively. The Bax/Bcl-2 ratio and caspase-3 activity were higher than the control group (Pv major-treated host lymphocytes dependent on p53 tumor suppressor via mitochondrial pathway may probably address as an auxiliary survival mechanism of L. major in CL patients. However, here is much work ahead to figure out the multiple functions played by apoptosis in the evasion of L. major.

  2. Leishmaniose cutânea experimental: I - sobre a susceptibilidade do primata Cebus apella (Cebidae a infecção pela Leishmania (Viannia lainsoni Silveira, Shaw, Braga e Ishikawa, 1987

    Directory of Open Access Journals (Sweden)

    Fernando T. Silveira

    1989-09-01

    Full Text Available Foi investigada a susceptibilidade do primata Cebus apella (Cebidae à infecção experimental pela Leishmaiua (Viannia lainsoni, com o objetivo de estudara patogenia desse parasita, ainda pouco conhecido para o homem. Dessa forma, cinco espécimens jovens daquele primata, 2 machos e 3 fêmeas, foram inoculados, intraderme, em oito sítios diferentes da região dorsal da cauda com 3 x 10(6 de promastigotas do parasita (MHOMZBR/81/M6426, Benevides, Pará, obtidas de cultura da fase estacionária. Em seguida às inoculações, a infecção experimental nos animais foi comprovada, não só pela presença de amastigotas do parasita na pele dos animais inoculados, mas, também, pela concomitância desse achado associado ao desenvolvimento de lesão cutânea nos pontos da pele onde o parasita foi inoculado. Diante desses resultados, ficou demonstrada a susceptibilidade do primata Cebus apella à infecção experimental pela Leishmama lainsoni cujo período de infecção durou quase quatro meses, suficiente para testar drogas antileishmanióticas e estudar a patogênese da doença causada por este parasita.The susceptibility of the monkey Cebus apella (Cebidae to experimental infection by Leishmania (Viannia lainsoni has been investigated. For this purpose, five young monkeys, 2 males and 3 females, were intradermally, inoculated, in eight different places along the dorsal surface of the tail with 3 x 10(6 promastigotes of the parasite (MHOM/BR/81/M6426, Benevides, Pará, from stationary phase culture in Difco B45 medium. After inoculations, infection in the monkeys was indicated by the presence of amastigotes in the skin lesions produced in these animals at the points of inoculation, confirming the susceptibility of the monkey Cebus apella to experimental infection by Leishmania lainsoni, with an infection period of four months. This represents a suitable period for testing antileishmanial drugs or studying the pathogenesis of the disease caused by

  3. Estudios sobre leishmaniasis tegumentaria en el Perú. I. Infección experimental de perros con cepas de leishmanias procedentes de casos de Uta

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    Arístides Herrer

    1951-01-01

    Full Text Available Se han inoculado varias series de perros con cepas de leishmanias procedentes de la forma clínica de la leishmaniasis tegumentaria conocida en el Perú con el nombre de uta, usando con tal objeto material tomado directamente de las lesiones utosas así como también cultivos del parásito. Los principales resultados obtenidos en tales inoculaciones son los siguientes: 1. Ha sido imposible infectar al perro con cultivos mantenidos solamente in vitro por espacio de cinco a ocho años, no obstante de haberse ensayado en tres series distintas de inoculaciones. 2. Se ha conseguido infecciones experimentales en el 87 por ciento de los perros que fueron inoculados con cultivos de reciente aislamiento. Aunque las inoculaciones fueran hechas bajo las mismas circunstancias en el dorso del hocico y la cara interna de una de las orejas, la infección se ha obtenido principalmente en el hocico. 3. También se ha logrado infectar perros inoculándoles material tomado directamente de las lesiones leishmaniásicas, ya sea de casos de uta o de lesiones producidas experimentalmente en otros perros.

  4. Physalis angulata induces death of promastigotes and amastigotes of Leishmania (Leishmania) amazonensis via the generation of reactive oxygen species.

    Science.gov (United States)

    Da Silva, B J M; Da Silva, R R P; Rodrigues, A P D; Farias, L H S; Do Nascimento, J L M; Silva, E O

    2016-03-01

    Leishmaniasis are a neglected group of emerging diseases that have been found in 98 countries and are caused by protozoa of the genus Leishmania. The therapy for leishmaniasis causes several side effects and leads to drug-resistant strains. Natural products from plants have exhibited activities against Leishmania in various experimental models. Physalis angulata is a widely used plant in popular medicine, and in the literature it has well-documented leishmanicidal activity. However, its mechanism of action is still unknown. Thus, this study aims to evaluate the mechanism driving the leishmanicidal activity of an aqueous extract of P. angulata root (AEPa). AEPa was effective against both promastigotes and intracellular amastigote forms of Leishmania amazonensis. This effect was mediated by an increase of reactive oxygen species (ROS), but not of nitric oxide (NO). The increased production of ROS induces cell death by phenotypes seems by apoptosis cell death in Leishmania, but not autophagy or necrosis. In addition, morphological analysis of macrophages showed that AEPa induced a high number of cytoplasmic projections, increased the volume of cytoplasm and number of vacuoles, caused cytoskeleton alterations and resulted in high spreading ability. AEPa also promoted superoxide anion (O2(-)) production in both uninfected macrophages and those infected with Leishmania. Therefore, these results revealed that AEPa causes cell death by phenotypes seems by apoptosis cell death in L. amazonensis and modulates macrophage activation through morphofunctional alterations and O2(-) generation to induce Leishmania death. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Serological reactivity of different antigenic preparations of Leishmania (Leishmania) amazonensis and the Leishmania braziliensis complex

    OpenAIRE

    Gomes-Silva, Adriano; Souza, Maria Aparecida de; Afonso-Cardoso,Sandra Regina; Andrade, Lívia Resende; Dietze, Reynaldo; Lemos, Elenice; Belli, Alejandro; Favoreto Júnior, Silvio; Ferreira,Marcelo Simão

    2008-01-01

    Total antigen from Leishmania (Leishmania) amazonensis and isolates from the Leishmania braziliensis complex, along with their respective antigenic fractions obtained by affinity chromatography on concanavalin-A-Sepharose and jacalin-agarose columns evaluated using immunoenzymatic ELISA assay. For this, serum samples from 229 patients were used, grouped as American tegmental leishmaniasis (nº=58), visceral leishmaniasis (nº=28), Chagas disease (nº=49), malaria (nº=32), tuberculosis (nº=13) an...

  6. Vaccine development against Leishmania donovani

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    Amrita eDas

    2012-05-01

    Full Text Available Visceral leishmaniasis (VL caused by Leishmania donovani and Leishmania infantum/ chagasi represents the second most challenging infectious disease worldwide, affecting nearly 500,000 people and 60,000 deaths annually. Zoonotic VL (ZVL caused by L. infantum is re-emergent canid zoonoses which represents a complex epidemiological cycle in New world where domestic dogs serve as reservoir host responsible for potentially fatal human infection where dog culling is the only control measure for eliminating reservoir host. Lifelong immunity in human against reinfection has motivated several attempts in developing prophylactic vaccines against the disease but very few have progressed beyond experimental stage. Absence of any licensed vaccine along with high toxicity and increasing resistance to the current chemotherapeutic drugs has further complicated the situation in endemic regions of the world. Advances in vaccinology, including recombinant proteins, novel antigen-delivery systems/adjuvants, heterologous prime-boost regimens and strategies for intracellular antigen presentation, have contributed to recent advances in vaccine development against VL. Attempts to develop an effective vaccine for use in domestic dogs in areas of canine VL should be pursued for preventing human infection. Studies in animal models and human patients have revealed the pathogenic mechanisms of disease progression and features of protective immunity. This review will summarize the accumulated knowledge about pathogenesis, immune response and prerequisites for protective immunity against human VL. Authors will discuss promising vaccine targets, their developmental status and future prospects in a quest for rational vaccine development against VL. In addition, several challenges such as safety issues, a renewed and coordinated commitment to basic research, preclinical studies and trial design will be addressed to overcome the problems faced in developing effective vaccines

  7. Effects of Bone Marrow Mesenchymal Stromal Cell Therapy in Experimental Cutaneous Leishmaniasis in BALB/c Mice Induced by Leishmania amazonensis.

    Science.gov (United States)

    Pereira, Joyce Carvalho; Ramos, Tadeu Diniz; Silva, Johnatas Dutra; de Mello, Mirian França; Pratti, Juliana Elena Silveira; da Fonseca-Martins, Alessandra Marcia; Firmino-Cruz, Luan; Kitoko, Jamil Zola; Chaves, Suzana Passos; Gomes, Daniel Claudio De Oliveira; Diaz, Bruno Lourenço; Rocco, Patricia R M; de Matos Guedes, Herbert Leonel

    2017-01-01

    Cutaneous leishmaniasis remains both a public health and a therapeutic challenge. To date, no ideal therapy for cutaneous leishmaniasis has been identified, and no universally accepted therapeutic regimen and approved vaccines are available. Due to the mesenchymal stromal cell (MSC) immunomodulatory capacity, they have been applied in a wide variety of disorders, including infectious, inflammatory, and allergic diseases. We evaluated the potential effects of bone marrow MSC therapy in a murine model of cutaneous leishmaniasis. In vitro, coculture of infected macrophages with MSC increased parasite load on macrophages in comparison with controls (macrophages without MSCs). In vivo, BALB/c mice were infected with 2 × 10(6)Leishmania amazonensis (Josefa strain) promastigotes in the footpad. 7 and 37 days after infection, animals were treated with 1 × 10(5) MSCs, either intralesional (i.l.), i.e., in the same site of infection, or intravenously (i.v.), through the external jugular vein. Control animals received the same volume (50 µL) of phosphate-buffered saline by i.l. or i.v. routes. The lesion progression was assessed by its thickness measured by pachymetry. Forty-two days after infection, animals were euthanized and parasite burden in the footpad and in the draining lymph nodes was quantified by the limiting dilution assay (LDA), and spleen cells were phenotyped by flow cytometry. No significant difference was observed in lesion progression, regardless of the MSC route of administration. However, animals treated with i.v. MSCs presented a significant increase in parasite load in comparison with controls. On the other hand, no harmful effect due to MSCs i.l. administered was observed. The spleen cellular profile analysis showed an increase of IL-10 producing T CD4(+) and TCD8(+) cells in the spleen only in mice treated with i.v. MSC. The excessive production of IL-10 could be associated with the disease-aggravating effects of MSC therapy when

  8. Effects of Bone Marrow Mesenchymal Stromal Cell Therapy in Experimental Cutaneous Leishmaniasis in BALB/c Mice Induced by Leishmania amazonensis

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    Joyce Carvalho Pereira

    2017-08-01

    Full Text Available Cutaneous leishmaniasis remains both a public health and a therapeutic challenge. To date, no ideal therapy for cutaneous leishmaniasis has been identified, and no universally accepted therapeutic regimen and approved vaccines are available. Due to the mesenchymal stromal cell (MSC immunomodulatory capacity, they have been applied in a wide variety of disorders, including infectious, inflammatory, and allergic diseases. We evaluated the potential effects of bone marrow MSC therapy in a murine model of cutaneous leishmaniasis. In vitro, coculture of infected macrophages with MSC increased parasite load on macrophages in comparison with controls (macrophages without MSCs. In vivo, BALB/c mice were infected with 2 × 106Leishmania amazonensis (Josefa strain promastigotes in the footpad. 7 and 37 days after infection, animals were treated with 1 × 105 MSCs, either intralesional (i.l., i.e., in the same site of infection, or intravenously (i.v., through the external jugular vein. Control animals received the same volume (50 µL of phosphate-buffered saline by i.l. or i.v. routes. The lesion progression was assessed by its thickness measured by pachymetry. Forty-two days after infection, animals were euthanized and parasite burden in the footpad and in the draining lymph nodes was quantified by the limiting dilution assay (LDA, and spleen cells were phenotyped by flow cytometry. No significant difference was observed in lesion progression, regardless of the MSC route of administration. However, animals treated with i.v. MSCs presented a significant increase in parasite load in comparison with controls. On the other hand, no harmful effect due to MSCs i.l. administered was observed. The spleen cellular profile analysis showed an increase of IL-10 producing T CD4+ and TCD8+ cells in the spleen only in mice treated with i.v. MSC. The excessive production of IL-10 could be associated with the disease-aggravating effects of MSC therapy when

  9. Visceral leishmania model

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    Boukhalfa Fatima

    2015-01-01

    Full Text Available In this work we consider a mathematical model based on a system of ordinary differential equations describing the evolution of population of dogs infected by leishmania diseases. By analyzing the corresponding characteristic equations, the local stability of infection free equilibrium point and infection equilibrium point are discussed. It is shown that if the basic reproduction number R0 is less than one, the infection free equilibrium is locally asymptotically stable, whereas if the basic reproduction number R0 is great than one the infection equilibrium point is locally asymptotically stable, and the infection free equilibrium is unstable.

  10. Monocyte-Derived Signals Activate Human Natural Killer Cells in Response to Leishmania Parasites

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    Helena Messlinger

    2018-01-01

    Full Text Available Activated natural killer (NK cells release interferon (IFN-γ, which is crucial for the control of intracellular pathogens such as Leishmania. In contrast to experimental murine leishmaniasis, the human NK cell response to Leishmania is still poorly characterized. Here, we investigated the interaction of human blood NK cells with promastigotes of different Leishmania species (Leishmania major, Leishmania mexicana, Leishmania infantum, and Leishmania donovani. When peripheral blood mononuclear cells or purified NK cells and monocytes (all derived from healthy blood donors from Germany without a history of leishmaniasis were exposed to promastigotes, NK cells showed increased surface expression of the activation marker CD69. The extent of this effect varied depending on the Leishmania species; differences between dermotropic and viscerotropic L. infantum strains were not observed. Upregulation of CD69 required direct contact between monocytes and Leishmania and was partly inhibitable by anti-interleukin (IL-18. Unexpectedly, IL-18 was undetectable in most of the supernatants (SNs of monocyte/parasite cocultures. Confocal fluorescence microscopy of non-permeabilized cells revealed that Leishmania-infected monocytes trans-presented IL-18 to NK cells. Native, but not heat-treated SNs of monocyte/Leishmania cocultures also induced CD69 on NK cells, indicating the involvement of a soluble heat-labile factor other than IL-18. A role for the NK cell-activating cytokines IL-1β, IL-2, IL-12, IL-15, IL-21, and IFN-α/β was excluded. The increase of CD69 was not paralleled by NK cell IFN-γ production or enhanced cytotoxicity. However, prior exposure of NK cells to Leishmania parasites synergistically increased their IFN-γ release in response to IL-12, which was dependent on endogenous IL-18. CD1c+ dendritic cells were identified as possible source of Leishmania-induced IL-12. Finally, we observed that direct contact between Leishmania and NK cells

  11. The activity of azithromycin against Leishmania (Viannia braziliensis and Leishmania (Leishmania amazonensis in the golden hamster model A atividade da azitromicina contra a Leishmania (Viannia braziliensis e a Leishmania (Leishmania amazonensis no modelo golden hamster

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    Ángel Sinagra

    2007-12-01

    Full Text Available New therapeutic alternatives against leishmaniasis remain a priority. The activity of azithromycin against Leishmania (Leishmania major has been previously demonstrated. Different responses among species of Leishmania make species-specific drug screening necessary. The activity of azithromycin against Leishmania (Viannia braziliensis and Leishmania (Leishmania amazonensis was evaluated in golden hamsters infected through footpad injections of metacyclic promastigotes, and compared with untreated controls and animals treated with meglumine antimoniate. Footpad thickness, lesion cultures and dissemination sites were analyzed. Treatment of golden hamsters with oral azithromycin at 450mg/kg had no activity against infections with Leishmania (Leishmania amazonensis. For infections due to Leishmania (Viannia braziliensis, azithromycin demonstrated significant activity relative to untreated controls, but inferior to meglumine antimoniate, for controlling lesion size. Neither drug was able to totally eliminate parasites from the lesions. It was concluded that azithromycin has activity against Leishmania (Viannia braziliensis but not against Leishmania (Leishmania amazonensis in this model.Novas alternativas terapêuticas contra a leishmaniose são ainda uma prioridade. A atividade da azitromicina contra a Leishmania (Leishmania major foi anteriormente demonstrada. Diferentes respostas entre as espécies de Leishmania fazem com que um screening de drogas específicas para espécies seja necessário. A atividade da azitromicina contra a Leishmania (Viannia braziliensis e a Leishmania (Leishmania amazonensis foi avaliada em Golden hamsters infectados a través de injeções de promastigotas metacíclicas e comparando com controles sem tratamento e animais tratados com antimoniato de N-metil-glucamina. Foram analisadas a espessura da pata, a cultura das lesões e disseminação para órgãos internos. A azitromicina oral em dose de 450mg/kg não teve

  12. In vitro Anti-Leishmania Activity and Safety of Newly Synthesized ...

    African Journals Online (AJOL)

    In vitro Anti-Leishmania Activity and Safety of Newly Synthesized Thiazolo Pyrimidine Derivatives Augmented with Interleukine-12 (IL-12) in BALB/c Mice Experimentally- Infected with Cutaneous Leishmaniasis.

  13. Cross-protective efficacy from a immunogen firstly identified in Leishmania infantum against tegumentary leishmaniasis.

    Science.gov (United States)

    Martins, V T; Lage, D P; Duarte, M C; Costa, L E; Chávez-Fumagalli, M A; Roatt, B M; Menezes-Souza, D; Tavares, C A P; Coelho, E A F

    2016-02-01

    Experimental vaccine candidates have been evaluated to prevent leishmaniasis, but no commercial vaccine has been proved to be effective against more than one parasite species. LiHyT is a Leishmania-specific protein that was firstly identified as protective against Leishmania infantum. In this study, LiHyT was evaluated as a vaccine to against two Leishmania species causing tegumentary leishmaniasis (TL): Leishmania major and Leishmania braziliensis. BALB/c mice were immunized with rLiHyT plus saponin and lately challenged with promastigotes of the two parasite species. The immune response generated was evaluated before and 10 weeks after infection, as well as the parasite burden at this time after infection. The vaccination induced a Th1 response, which was characterized by the production of IFN-γ, IL-12 and GM-CSF, as well as by high levels of IgG2a antibodies, after in vitro stimulation using both the protein and parasite extracts. After challenge, vaccinated mice showed significant reductions in their infected footpads, as well as in the parasite burden in the tissue and organs evaluated, when compared to the control groups. The anti-Leishmania Th1 response was maintained after infection, being the IFN-γ production based mainly on CD4(+) T cells. We described one conserved Leishmania-specific protein that could compose a pan-Leishmania vaccine. © 2016 John Wiley & Sons Ltd.

  14. Innate Immunity against Leishmania Infections

    Science.gov (United States)

    Gurung, Prajwal; Kanneganti, Thirumala-Devi

    2015-01-01

    Leishmaniasis is a major health problem that affects more than 300 million people throughout the world. The morbidity associated with the disease causes serious economic burden in Leishmania endemic regions. Despite the morbidity and economic burden associated with Leishmaniasis, this disease rarely gets noticed and is still categorized under neglected tropical diseases. The lack of research combined with the ability of Leishmania to evade immune recognition has rendered our efforts to design therapeutic treatments or vaccines challenging. Herein, we review the literature on Leishmania from innate immune perspective and discuss potential problems as well as solutions and future directions that could aid in identifying novel therapeutic targets to eliminate this parasite. PMID:26249747

  15. Susceptibility of spiny rats (Proechimys semispinosus to Leishmania (Viannia panamensis and Leishmania (Leishmania chagasi

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    BL Travi

    2002-09-01

    Full Text Available The role of Proechimys semispinosus as reservoir of Leishmania (Viannia panamensis on the Colombian Pacific coast was experimentally evaluated. The susceptibility to L. chagasi also was assessed to determine the utility of this rodent as a model for studying reservoir characteristics in the laboratory. Wild-caught animals were screened for natural trypanosomatid infections, and negative individuals were inoculated intradermally (ID in the snout or feet with 10(7 promastigotes of L. panamensis. L. chagasi was inoculated intracardially (10(7 promastigotes or ID in the ear (10(8 promastigotes. PCR-hybridization showed that 15% of 33 spiny rats were naturally infected with L. Viannia sp. Animals experimentally infected with L. panamensis developed non-ulcerated lesions that disappeared by the 7th week post-infection (p.i. and became more resistant upon reinfection. Infectivity to sand flies was low (1/20-1/48 infected/fed flies and transient, and both culture and PCR-hybridization showed that L. panamensis was cleared by the 13th week p.i. Animals inoculated with L. chagasi became subclinically infected and were non-infective to sand flies. Transient infectivity to vectors of spiny rats infected with L. panamensis, combined with population characteristics, e.g., abundance, exploitation of degraded habitats and high reproductive rates, could make them epidemiologically suitable reservoirs.

  16. Study of ionizing radiation as a tool for select promastigotes forms of Leishmania Amazonensis, and the megalomaniac response in experimental models; Estudo do uso da radiacao ionizante como ferramenta de selecao de formas promastigotas metaciclicas de Leishmania amazonensis, e a inducao de resposta imunologica em modelos experimentais

    Energy Technology Data Exchange (ETDEWEB)

    Bonetti, Franco Claudio

    2006-07-01

    Actually, millions of people around the globe are under the risk of infection by a protozoan transmitted by a bit of a sand fly. This parasite is a Leishmania spp. This causes a wide spectrum disease, since a cutaneous disease to a visceral one. The cutaneous form is the major clinical manifestation (above 90%). The ionizing radiation, produced in a {sup 60}Co font, had being successes used to promote physical-chemical transformations on different protozoan, including Leishmania spp. In previous work was determined that promastigotes forms of Leishmania amazonensis, irradiated with different doses of radiation, lost their viability maintaining, however, their immunogenicity. In this work, was studied the use of ionizing radiation as a tool for selection of meta cyclic forms of the parasite in axenic culture, for a possible efficient irradiated immuno gene production. Our results shown that cultures irradiated with 400 Gy of gamma irradiation, has 75% of metacyclic form, which are capable to produce, in vitro, an infection that is similar the natural occurrence. These irradiated parasites have their internal cellular structure modified, maintaining their external structure intact. Susceptible strain of mice immunized with leishmania irradiated with different doses had high immunoglobulin production, and maintained this production after the challenge with naive parasites. In other strains this default was similar, however in lower titles. Immunodeficient mice didn't produce immunoglobulin nor on the immunization or on the challenge. (author)

  17. Parasites Cryptosporidium parvum, Leishmania, Plasmodium ...

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Parasites Cryptosporidium parvum, Leishmania, Plasmodium falciparum (malaria), Schistosoma. Cancer-associated antigens Carcinoembryonic antigen (CEA), melanoma-associated antigen, the MHC molecule HLA-B7.

  18. Cell migration induced by Leishmania (Leishmania amazonensis, Leishmania (Leishmania major and Leishmania (Viannia braziliensis into the peritoneal cavity of BALB/c mice

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    DT Wakimoto

    2010-01-01

    Full Text Available In American cutaneous leishmaniasis, the initial infection phase is characterized by recruitment of neutrophils and monocytes. The migration of these cells in response to the presence of Leishmania in the peritoneum of affected animals remains unclear. The objective of this study was to investigate cell migration to the peritoneum of BALB/c mice after infection with Leishmania (Leishmania amazonensis, Leishmania (Viannia braziliensis and Leishmania (Leishmania major. Initially, Leishmania spp. was intraperitoneally inoculated in five groups of six animals each and the cell migration was analyzed 0, 3, 6, 12, 24 and 48 hours after infection. Different cell counts were performed with a staining kit and showed a higher percentage of polymorphonuclear than mononuclear cells in all three species studied. The total cell count revealed peak migration in L. (L. amazonensis and L. (L. major at six hours, and in L. (V. braziliensis at 12 hours. These results suggest that factors released from different cell types probably act by attracting polymorphonuclear cells, with the peak migration most likely depending on the species of Leishmania inoculated into the host.

  19. Leishmania (L. mexicana infected bats in Mexico: novel potential reservoirs.

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    Miriam Berzunza-Cruz

    2015-01-01

    Full Text Available Leishmania (Leishmania mexicana causes cutaneous leishmaniasis, an endemic zoonosis affecting a growing number of patients in the southeastern states of Mexico. Some foci are found in shade-grown cocoa and coffee plantations, or near perennial forests that provide rich breeding grounds for the sand fly vectors, but also harbor a variety of bat species that live off the abundant fruits provided by these shade-giving trees. The close proximity between sand flies and bats makes their interaction feasible, yet bats infected with Leishmania (L. mexicana have not been reported. Here we analyzed 420 bats from six states of Mexico that had reported patients with leishmaniasis. Tissues of bats, including skin, heart, liver and/or spleen were screened by PCR for Leishmania (L. mexicana DNA. We found that 41 bats (9.77%, belonging to 13 species, showed positive PCR results in various tissues. The infected tissues showed no evidence of macroscopic lesions. Of the infected bats, 12 species were frugivorous, insectivorous or nectarivorous, and only one species was sanguivorous (Desmodus rotundus, and most of them belonged to the family Phyllostomidae. The eco-region where most of the infected bats were caught is the Gulf Coastal Plain of Chiapas and Tabasco. Through experimental infections of two Tadarida brasiliensis bats in captivity, we show that this species can harbor viable, infective Leishmania (L. mexicana parasites that are capable of infecting BALB/c mice. We conclude that various species of bats belonging to the family Phyllostomidae are possible reservoir hosts for Leishmania (L. mexicana, if it can be shown that such bats are infective for the sand fly vector. Further studies are needed to determine how these bats become infected, how long the parasite remains viable inside these potential hosts and whether they are infective to sand flies to fully evaluate their impact on disease epidemiology.

  20. Leishmania (L.) mexicana Infected Bats in Mexico: Novel Potential Reservoirs

    Science.gov (United States)

    Berzunza-Cruz, Miriam; Rodríguez-Moreno, Ángel; Gutiérrez-Granados, Gabriel; González-Salazar, Constantino; Stephens, Christopher R.; Hidalgo-Mihart, Mircea; Marina, Carlos F.; Rebollar-Téllez, Eduardo A.; Bailón-Martínez, Dulce; Balcells, Cristina Domingo; Ibarra-Cerdeña, Carlos N.; Sánchez-Cordero, Víctor; Becker, Ingeborg

    2015-01-01

    Leishmania (Leishmania) mexicana causes cutaneous leishmaniasis, an endemic zoonosis affecting a growing number of patients in the southeastern states of Mexico. Some foci are found in shade-grown cocoa and coffee plantations, or near perennial forests that provide rich breeding grounds for the sand fly vectors, but also harbor a variety of bat species that live off the abundant fruits provided by these shade-giving trees. The close proximity between sand flies and bats makes their interaction feasible, yet bats infected with Leishmania (L.) mexicana have not been reported. Here we analyzed 420 bats from six states of Mexico that had reported patients with leishmaniasis. Tissues of bats, including skin, heart, liver and/or spleen were screened by PCR for Leishmania (L.) mexicana DNA. We found that 41 bats (9.77%), belonging to 13 species, showed positive PCR results in various tissues. The infected tissues showed no evidence of macroscopic lesions. Of the infected bats, 12 species were frugivorous, insectivorous or nectarivorous, and only one species was sanguivorous (Desmodus rotundus), and most of them belonged to the family Phyllostomidae. The eco-region where most of the infected bats were caught is the Gulf Coastal Plain of Chiapas and Tabasco. Through experimental infections of two Tadarida brasiliensis bats in captivity, we show that this species can harbor viable, infective Leishmania (L.) mexicana parasites that are capable of infecting BALB/c mice. We conclude that various species of bats belonging to the family Phyllostomidae are possible reservoir hosts for Leishmania (L.) mexicana, if it can be shown that such bats are infective for the sand fly vector. Further studies are needed to determine how these bats become infected, how long the parasite remains viable inside these potential hosts and whether they are infective to sand flies to fully evaluate their impact on disease epidemiology. PMID:25629729

  1. Leishmania (L.) mexicana infected bats in Mexico: novel potential reservoirs.

    Science.gov (United States)

    Berzunza-Cruz, Miriam; Rodríguez-Moreno, Ángel; Gutiérrez-Granados, Gabriel; González-Salazar, Constantino; Stephens, Christopher R; Hidalgo-Mihart, Mircea; Marina, Carlos F; Rebollar-Téllez, Eduardo A; Bailón-Martínez, Dulce; Balcells, Cristina Domingo; Ibarra-Cerdeña, Carlos N; Sánchez-Cordero, Víctor; Becker, Ingeborg

    2015-01-01

    Leishmania (Leishmania) mexicana causes cutaneous leishmaniasis, an endemic zoonosis affecting a growing number of patients in the southeastern states of Mexico. Some foci are found in shade-grown cocoa and coffee plantations, or near perennial forests that provide rich breeding grounds for the sand fly vectors, but also harbor a variety of bat species that live off the abundant fruits provided by these shade-giving trees. The close proximity between sand flies and bats makes their interaction feasible, yet bats infected with Leishmania (L.) mexicana have not been reported. Here we analyzed 420 bats from six states of Mexico that had reported patients with leishmaniasis. Tissues of bats, including skin, heart, liver and/or spleen were screened by PCR for Leishmania (L.) mexicana DNA. We found that 41 bats (9.77%), belonging to 13 species, showed positive PCR results in various tissues. The infected tissues showed no evidence of macroscopic lesions. Of the infected bats, 12 species were frugivorous, insectivorous or nectarivorous, and only one species was sanguivorous (Desmodus rotundus), and most of them belonged to the family Phyllostomidae. The eco-region where most of the infected bats were caught is the Gulf Coastal Plain of Chiapas and Tabasco. Through experimental infections of two Tadarida brasiliensis bats in captivity, we show that this species can harbor viable, infective Leishmania (L.) mexicana parasites that are capable of infecting BALB/c mice. We conclude that various species of bats belonging to the family Phyllostomidae are possible reservoir hosts for Leishmania (L.) mexicana, if it can be shown that such bats are infective for the sand fly vector. Further studies are needed to determine how these bats become infected, how long the parasite remains viable inside these potential hosts and whether they are infective to sand flies to fully evaluate their impact on disease epidemiology.

  2. Vector transmission of leishmania abrogates vaccine-induced protective immunity.

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    Nathan C Peters

    2009-06-01

    Full Text Available Numerous experimental vaccines have been developed to protect against the cutaneous and visceral forms of leishmaniasis caused by infection with the obligate intracellular protozoan Leishmania, but a human vaccine still does not exist. Remarkably, the efficacy of anti-Leishmania vaccines has never been fully evaluated under experimental conditions following natural vector transmission by infected sand fly bite. The only immunization strategy known to protect humans against natural exposure is "leishmanization," in which viable L. major parasites are intentionally inoculated into a selected site in the skin. We employed mice with healed L. major infections to mimic leishmanization, and found tissue-seeking, cytokine-producing CD4+ T cells specific for Leishmania at the site of challenge by infected sand fly bite within 24 hours, and these mice were highly resistant to sand fly transmitted infection. In contrast, mice vaccinated with a killed vaccine comprised of autoclaved L. major antigen (ALM+CpG oligodeoxynucleotides that protected against needle inoculation of parasites, showed delayed expression of protective immunity and failed to protect against infected sand fly challenge. Two-photon intra-vital microscopy and flow cytometric analysis revealed that sand fly, but not needle challenge, resulted in the maintenance of a localized neutrophilic response at the inoculation site, and removal of neutrophils following vector transmission led to increased parasite-specific immune responses and promoted the efficacy of the killed vaccine. These observations identify the critical immunological factors influencing vaccine efficacy following natural transmission of Leishmania.

  3. Vector transmission of leishmania abrogates vaccine-induced protective immunity.

    Science.gov (United States)

    Peters, Nathan C; Kimblin, Nicola; Secundino, Nagila; Kamhawi, Shaden; Lawyer, Phillip; Sacks, David L

    2009-06-01

    Numerous experimental vaccines have been developed to protect against the cutaneous and visceral forms of leishmaniasis caused by infection with the obligate intracellular protozoan Leishmania, but a human vaccine still does not exist. Remarkably, the efficacy of anti-Leishmania vaccines has never been fully evaluated under experimental conditions following natural vector transmission by infected sand fly bite. The only immunization strategy known to protect humans against natural exposure is "leishmanization," in which viable L. major parasites are intentionally inoculated into a selected site in the skin. We employed mice with healed L. major infections to mimic leishmanization, and found tissue-seeking, cytokine-producing CD4+ T cells specific for Leishmania at the site of challenge by infected sand fly bite within 24 hours, and these mice were highly resistant to sand fly transmitted infection. In contrast, mice vaccinated with a killed vaccine comprised of autoclaved L. major antigen (ALM)+CpG oligodeoxynucleotides that protected against needle inoculation of parasites, showed delayed expression of protective immunity and failed to protect against infected sand fly challenge. Two-photon intra-vital microscopy and flow cytometric analysis revealed that sand fly, but not needle challenge, resulted in the maintenance of a localized neutrophilic response at the inoculation site, and removal of neutrophils following vector transmission led to increased parasite-specific immune responses and promoted the efficacy of the killed vaccine. These observations identify the critical immunological factors influencing vaccine efficacy following natural transmission of Leishmania.

  4. Modulation of Innate Immune Mechanisms to Enhance Leishmania Vaccine-Induced Immunity: Role of Coinhibitory Molecules

    OpenAIRE

    Gannavaram, Sreenivas; Bhattacharya, Parna; Ismail, Nevien; Kaul, Amit; Singh, Rakesh; Nakhasi, Hira L.

    2016-01-01

    No licensed human vaccines are currently available against any parasitic disease including leishmaniasis. Several antileishmanial vaccine formulations have been tested in various animal models, including genetically modified live-attenuated parasite vaccines. Experimental infection studies have shown that Leishmania parasites utilize a broad range of strategies to undermine effector properties of host phagocytic cells, i.e., dendritic cells (DCs) and macrophages (MΦ). Furthermore, Leishmania ...

  5. Structurally optimized analogs of the retrograde trafficking inhibitor Retro-2cycl limit Leishmania infections.

    Science.gov (United States)

    Craig, Evan; Huyghues-Despointes, Charles-Eugene; Yu, Chun; Handy, Emma L; Sello, Jason K; Kima, Peter E

    2017-05-01

    In infected mammalian cells, Leishmania parasites reside within specialized compartments called parasitophorous vacuoles (LPVs). We have previously shown that Retro-2, a member of a novel class of small retrograde pathway inhibitors caused reduced LPV sizes and lower parasite numbers during experimental L. mexicana sp. infections. The purpose of this study was to determine if structural analogs of Retro-2cycl reported to have superior potency in the inhibition of retrograde pathway-dependent phenomena (i.e., polyomavirus cellular infection by polyomavrius and Shiga toxin trafficking in cells) are also more effective than the parent compound at controlling Leishmania infections. In addition to their effects on LPV development, we show that two optimized analogs of Retro-2cycl, DHQZ 36 and DHQZ 36.1 limit Leishmania amazonensis infection in macrophages at EC50 of 13.63+/-2.58μM and10.57+/-2.66μM, respectively, which is significantly lower than 40.15μM the EC50 of Retro-2cycl. In addition, these analogs caused a reversal in Leishmania induced suppression of IL-6 release by infected cells after LPS activation. Moreover, we show that in contrast to Retro-2cycl that is Leishmania static, the analogs can kill Leishmania parasites in axenic cultures, which is a desirable attribute for any drug to treat Leishmania infections. Together, these studies validate and extend the published structure-activity relationship analyses of Retro-2cycl.

  6. Novel selective inhibitor of Leishmania (Leishmania) amazonensis arginase.

    Science.gov (United States)

    da Silva, Edson R; Boechat, Nubia; Pinheiro, Luiz C S; Bastos, Monica M; Costa, Carolina C P; Bartholomeu, Juliana C; da Costa, Talita H

    2015-11-01

    Arginase is a glycosomal enzyme in Leishmania that is involved in polyamine and trypanothione biosynthesis. The central role of arginase in Leishmania (Leishmania) amazonensis was demonstrated by the generation of two mutants: one with an arginase lacking the glycosomal addressing signal and one in which the arginase-coding gene was knocked out. Both of these mutants exhibited decreased infectivity. Thus, arginase seems to be a potential drug target for Leishmania treatment. In an attempt to search for arginase inhibitors, 29 derivatives of the [1,2,4]triazolo[1,5-a]pyrimidine system were tested against Leishmania (Leishmania) amazonensis arginase in vitro. The [1,2,4]triazolo[1,5-a]pyrimidine scaffold containing R1  = CF3 exhibited greater activity against the arginase rather than when the substituent R1  = CH3 in the 2-position. The novel compound 2-(5-methyl-2-(trifluoromethyl)-[1,2,4]triazolo[1,5-a]pyrimidin-7-yl)hydrazinecarbothioamide (30) was the most potent, inhibiting arginase by a non-competitive mechanism, with the Ki and IC50 values for arginase inhibition estimated to be 17 ± 1 μm and 16.5 ± 0.5 μm, respectively. These results can guide the development of new drugs against leishmaniasis based on [1,2,4]triazolo[1,5-a]pyrimidine derivatives targeting the arginase enzyme. © 2015 John Wiley & Sons A/S.

  7. Prevalence and Distribution of Leishmania RNA Virus 1 in Leishmania Parasites from French Guiana.

    Science.gov (United States)

    Ginouvès, Marine; Simon, Stéphane; Bourreau, Eliane; Lacoste, Vincent; Ronet, Catherine; Couppié, Pierre; Nacher, Mathieu; Demar, Magalie; Prévot, Ghislaine

    2016-01-01

    In South America, the presence of the Leishmania RNA virus type 1 (LRV1) was described in Leishmania guyanensis and Leishmania braziliensis strains. The aim of this study was to determine the prevalence distribution of LRV1 in Leishmania isolates in French Guiana given that, in this French overseas department, most Leishmania infections are due to these parasite species. The presence of the virus was observed in 74% of Leishmania spp. isolates, with a highest presence in the internal areas of the country. © The American Society of Tropical Medicine and Hygiene.

  8. Characterization of glycolytic enzymes--rAldolase and rEnolase of Leishmania donovani, identified as Th1 stimulatory proteins, for their immunogenicity and immunoprophylactic efficacies against experimental visceral leishmaniasis.

    Science.gov (United States)

    Gupta, Reema; Kumar, Vikash; Kushawaha, Pramod Kumar; Tripathi, Chandradev Pati; Joshi, Sumit; Sahasrabuddhe, Amogh Anant; Mitra, Kalyan; Sundar, Shyam; Siddiqi, Mohammad Imran; Dube, Anuradha

    2014-01-01

    Th1 immune responses play an important role in controlling Visceral Leishmaniasis (VL) hence, Leishmania proteins stimulating T-cell responses in host, are thought to be good vaccine targets. Search of such antigens eliciting cellular responses in Peripheral blood mononuclear cells (PBMCs) from cured/exposed/Leishmania patients and hamsters led to the identification of two enzymes of glycolytic pathway in the soluble lysate of a clinical isolate of Leishmania donovani--Enolase (LdEno) and aldolase (LdAld) as potential Th1 stimulatory proteins. The present study deals with the molecular and immunological characterizations of LdEno and LdAld. The successfully cloned and purified recombinant proteins displayed strong ability to proliferate lymphocytes of cured hamsters' along with significant nitric-oxide production and generation of Th1-type cytokines (IFN-γ and IL-12) from stimulated PBMCs of cured/endemic VL patients. Assessment of their prophylactic potentials revealed ∼ 90% decrease in parasitic burden in rLdEno vaccinated hamsters against Leishmania challenge, strongly supported by an increase in mRNA expression levels of iNOS, IFN-γ, TNF-α and IL-12 transcripts along with extreme down-regulation of TGF-β, IL-4 and IL-10. However, animals vaccinated with rLdAld showed comparatively lesser prophylactic efficacy (∼ 65%) with inferior immunological response. Further, with a possible implication in vaccine design against VL, identification of potential T-cell epitopes of both the proteins was done using computational approach. Additionally, in-silico 3-D modelling of the proteins was done in order to explore the possibility of exploiting them as potential drug targets. The comparative molecular and immunological characterizations strongly suggest rLdEno as potential vaccine candidate against VL and supports the notion of its being effective T-cell stimulatory protein.

  9. Dissecting Leishmania infantum Energy Metabolism - A Systems Perspective.

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    Abhishek Subramanian

    Full Text Available Leishmania infantum, causative agent of visceral leishmaniasis in humans, illustrates a complex lifecycle pertaining to two extreme environments, namely, the gut of the sandfly vector and human macrophages. Leishmania is capable of dynamically adapting and tactically switching between these critically hostile situations. The possible metabolic routes ventured by the parasite to achieve this exceptional adaptation to its varying environments are still poorly understood. In this study, we present an extensively reconstructed energy metabolism network of Leishmania infantum as an attempt to identify certain strategic metabolic routes preferred by the parasite to optimize its survival in such dynamic environments. The reconstructed network consists of 142 genes encoding for enzymes performing 237 reactions distributed across five distinct model compartments. We annotated the subcellular locations of different enzymes and their reactions on the basis of strong literature evidence and sequence-based detection of cellular localization signal within a protein sequence. To explore the diverse features of parasite metabolism the metabolic network was implemented and analyzed as a constraint-based model. Using a systems-based approach, we also put forth an extensive set of lethal reaction knockouts; some of which were validated using published data on Leishmania species. Performing a robustness analysis, the model was rigorously validated and tested for the secretion of overflow metabolites specific to Leishmania under varying extracellular oxygen uptake rate. Further, the fate of important non-essential amino acids in L. infantum metabolism was investigated. Stage-specific scenarios of L. infantum energy metabolism were incorporated in the model and key metabolic differences were outlined. Analysis of the model revealed the essentiality of glucose uptake, succinate fermentation, glutamate biosynthesis and an active TCA cycle as driving forces for parasite

  10. LeishCyc: a biochemical pathways database for Leishmania major

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    Doyle Maria A

    2009-06-01

    Full Text Available Abstract Background Leishmania spp. are sandfly transmitted protozoan parasites that cause a spectrum of diseases in more than 12 million people worldwide. Much research is now focusing on how these parasites adapt to the distinct nutrient environments they encounter in the digestive tract of the sandfly vector and the phagolysosome compartment of mammalian macrophages. While data mining and annotation of the genomes of three Leishmania species has provided an initial inventory of predicted metabolic components and associated pathways, resources for integrating this information into metabolic networks and incorporating data from transcript, protein, and metabolite profiling studies is currently lacking. The development of a reliable, expertly curated, and widely available model of Leishmania metabolic networks is required to facilitate systems analysis, as well as discovery and prioritization of new drug targets for this important human pathogen. Description The LeishCyc database was initially built from the genome sequence of Leishmania major (v5.2, based on the annotation published by the Wellcome Trust Sanger Institute. LeishCyc was manually curated to remove errors, correct automated predictions, and add information from the literature. The ongoing curation is based on public sources, literature searches, and our own experimental and bioinformatics studies. In a number of instances we have improved on the original genome annotation, and, in some ambiguous cases, collected relevant information from the literature in order to help clarify gene or protein annotation in the future. All genes in LeishCyc are linked to the corresponding entry in GeneDB (Wellcome Trust Sanger Institute. Conclusion The LeishCyc database describes Leishmania major genes, gene products, metabolites, their relationships and biochemical organization into metabolic pathways. LeishCyc provides a systematic approach to organizing the evolving information about Leishmania

  11. LeishCyc: a biochemical pathways database for Leishmania major.

    Science.gov (United States)

    Doyle, Maria A; MacRae, James I; De Souza, David P; Saunders, Eleanor C; McConville, Malcolm J; Likić, Vladimir A

    2009-06-05

    Leishmania spp. are sandfly transmitted protozoan parasites that cause a spectrum of diseases in more than 12 million people worldwide. Much research is now focusing on how these parasites adapt to the distinct nutrient environments they encounter in the digestive tract of the sandfly vector and the phagolysosome compartment of mammalian macrophages. While data mining and annotation of the genomes of three Leishmania species has provided an initial inventory of predicted metabolic components and associated pathways, resources for integrating this information into metabolic networks and incorporating data from transcript, protein, and metabolite profiling studies is currently lacking. The development of a reliable, expertly curated, and widely available model of Leishmania metabolic networks is required to facilitate systems analysis, as well as discovery and prioritization of new drug targets for this important human pathogen. The LeishCyc database was initially built from the genome sequence of Leishmania major (v5.2), based on the annotation published by the Wellcome Trust Sanger Institute. LeishCyc was manually curated to remove errors, correct automated predictions, and add information from the literature. The ongoing curation is based on public sources, literature searches, and our own experimental and bioinformatics studies. In a number of instances we have improved on the original genome annotation, and, in some ambiguous cases, collected relevant information from the literature in order to help clarify gene or protein annotation in the future. All genes in LeishCyc are linked to the corresponding entry in GeneDB (Wellcome Trust Sanger Institute). The LeishCyc database describes Leishmania major genes, gene products, metabolites, their relationships and biochemical organization into metabolic pathways. LeishCyc provides a systematic approach to organizing the evolving information about Leishmania biochemical networks and is a tool for analysis

  12. Leishmania donovani develops resistance to drug combinations.

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    Raquel García-Hernández

    Full Text Available Drug combinations for the treatment of leishmaniasis represent a promising and challenging chemotherapeutic strategy that has recently been implemented in different endemic areas. However, the vast majority of studies undertaken to date have ignored the potential risk that Leishmania parasites could develop resistance to the different drugs used in such combinations. As a result, this study was designed to elucidate the ability of Leishmania donovani to develop experimental resistance to anti-leishmanial drug combinations. The induction of resistance to amphotericin B/miltefosine, amphotericin B/paromomycin, amphotericin B/Sb(III, miltefosine/paromomycin, and Sb(III/paromomycin was determined using a step-wise adaptation process to increasing drug concentrations. Intracellular amastigotes resistant to these drug combinations were obtained from resistant L. donovani promastigote forms, and the thiol and ATP levels and the mitochondrial membrane potential of the resistant lines were analysed. Resistance to drug combinations was obtained after 10 weeks and remained in the intracellular amastigotes. Additionally, this resistance proved to be unstable. More importantly, we observed that promastigotes/amastigotes resistant to one drug combination showed a marked cross-resistant profile to other anti-leishmanial drugs. Additionally, the thiol levels increased in resistant lines that remained protected against the drug-induced loss of ATP and mitochondrial membrane potential. We have therefore demonstrated that different resistance patterns can be obtained in L. donovani depending upon the drug combinations used. Resistance to the combinations miltefosine/paromomycin and Sb(III/paromomycin is easily obtained experimentally. These results have been validated in intracellular amastigotes, and have important relevance for ensuring the long-term efficacy of drug combinations.

  13. Preparation of highly infective Leishmania promastigotes by cultivation on SNB-9 biphasic medium.

    Science.gov (United States)

    Grekov, Igor; Svobodová, Milena; Nohýnková, Eva; Lipoldová, Marie

    2011-12-01

    Protozoan hemoflagellates Leishmania are causative agents of leishmaniases and an important biological model for study of host-pathogen interaction. A wide range of methods of Leishmania cultivation on both biphasic and liquid media is available. Biphasic media are considered to be superior for initial isolation of the parasites and obtaining high promastigote infectivity; however, liquid media are more suitable for large-scale experiments. The aim of the present study was the adaptation and optimization of the cultivation of Leishmania promastigotes on a biphasic SNB-9 (saline-neopeptone-blood 9) medium that was originally developed for Trypanosoma cultivation and combines the advantages of biphasic and liquid media. SNB-9 medium is characterized with a large volume of the liquid phase, which facilitates the manipulation with the culture and provides parasite yields comparable to parasite yields on such liquid medium as Schneider's Insect Medium. We demonstrate that SNB-9 very considerably surpasses Schneider's Insect Medium in in vitro infectivity of the parasites. Additionally, we show that the ratio of apoptotic parasites, which are important for the infectivity of the inoculum, in Leishmania culture in SNB-9 is higher than in Leishmania culture in Schneider's Insect Medium. Thus, we demonstrate that the cultivation of Leishmania on SNB-9 reliably yields highly infective promastigotes suitable for experimental infection. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Persistence of Leishmania antigen in C57Bl/6j inbred mice infected with Leishmania (Leishmania amazonensis Persistência do antígeno da Leishmania no camundongo isogênico C57Bl/6j infectado com a Leishmania (Leishmania amazonensis

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    C. Vasconcellos

    1999-07-01

    Full Text Available PURPOSE. To develop an animal model for studying mucocutaneous leishmaniasis. METHODS. The hind footpad of C57Bl/6j inbred mice was experimentally infected with 10(7 Leishmania (Leishmania amazonensis promastigote and the skin was studied through light and electron transmission microscopy and immunohistochemistry (PAP techniques. RESULTS. There were morphological evidences of cellular immune mechanisms and hypersensitivity reaction after eight weeks of infection and metastasis and well shaped parasites at ultrastructural level by fifty-one weeks post infection. Relapse of infection with mucosa lesions occurred around the 50th week after inoculation. CONCLUSION. The use of this animal model in long term follow up could be an useful experimental model for human mucocutaneous leishmaniasis.OBJETIVO. Desenvolver um modelo experimental para o estudo da leishmaniose cutâneo-mucosa. MÉTODOS. O coxim plantar traseiro de camundongos isogênicos C57Bl/6j foi inoculado com 10(7 formas promastigotas da Leishmania (Leishmania amazonensis e a pele foi estudada através da microscopia óptica e eletrônica e de técnica imunohistoquímica (PAP. RESULTADOS. Ocorreram evidências morfológicas de mecanismos imunes mediados por células, concomitantemente ao de reação de hipersensibilidade, após a oitava semana de infecção e a presença de parasitas com ultraestrutura preservada na quinquagésima primeira semana após a infecção. Houve recidiva da infecção com surgimento de lesões mucosas por volta da 50a semana pós inoculação. CONCLUSÃO. Este modelo animal, com um período de tempo de seguimento prolongado, poderia ser empregado como modelo para o estudo experimental da leishmaniose cutâneo-mucosa.

  15. Detection of Leishmania RNA virus in Leishmania parasites.

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    Haroun Zangger

    Full Text Available Patients suffering from cutaneous leishmaniasis (CL caused by New World Leishmania (Viannia species are at high risk of developing mucosal (ML or disseminated cutaneous leishmaniasis (DCL. After the formation of a primary skin lesion at the site of the bite by a Leishmania-infected sand fly, the infection can disseminate to form secondary lesions. This metastatic phenotype causes significant morbidity and is often associated with a hyper-inflammatory immune response leading to the destruction of nasopharyngeal tissues in ML, and appearance of nodules or numerous ulcerated skin lesions in DCL. Recently, we connected this aggressive phenotype to the presence of Leishmania RNA virus (LRV in strains of L. guyanensis, showing that LRV is responsible for elevated parasitaemia, destructive hyper-inflammation and an overall exacerbation of the disease. Further studies of this relationship and the distribution of LRVs in other Leishmania strains and species would benefit from improved methods of viral detection and quantitation, especially ones not dependent on prior knowledge of the viral sequence as LRVs show significant evolutionary divergence.This study reports various techniques, among which, the use of an anti-dsRNA monoclonal antibody (J2 stands out for its specific and quantitative recognition of dsRNA in a sequence-independent fashion. Applications of J2 include immunofluorescence, ELISA and dot blot: techniques complementing an arsenal of other detection tools, such as nucleic acid purification and quantitative real-time-PCR. We evaluate each method as well as demonstrate a successful LRV detection by the J2 antibody in several parasite strains, a freshly isolated patient sample and lesion biopsies of infected mice.We propose that refinements of these methods could be transferred to the field for use as a diagnostic tool in detecting the presence of LRV, and potentially assessing the LRV-related risk of complications in cutaneous leishmaniasis.

  16. Arginase expression modulates nitric oxide production in Leishmania (Leishmania) amazonensis.

    Science.gov (United States)

    Acuña, Stephanie Maia; Aoki, Juliana Ide; Laranjeira-Silva, Maria Fernanda; Zampieri, Ricardo Andrade; Fernandes, Juliane Cristina Ribeiro; Muxel, Sandra Marcia; Floeter-Winter, Lucile Maria

    2017-01-01

    Arginase is an enzyme that converts L-arginine to urea and L-ornithine, an essential substrate for the polyamine pathway supporting Leishmania (Leishmania) amazonensis replication and its survival in the mammalian host. L-arginine is also the substrate of macrophage nitric oxide synthase 2 (NOS2) to produce nitric oxide (NO) that kills the parasite. This competition can define the fate of Leishmania infection. The transcriptomic profiling identified a family of oxidoreductases in L. (L.) amazonensis wild-type (La-WT) and L. (L.) amazonensis arginase knockout (La-arg-) promastigotes and axenic amastigotes. We highlighted the identification of an oxidoreductase that could act as nitric oxide synthase-like (NOS-like), due to the following evidences: conserved domain composition, the participation of NO production during the time course of promastigotes growth and during the axenic amastigotes differentiation, regulation dependence on arginase activity, as well as reduction of NO amount through the NOS activity inhibition. NO quantification was measured by DAF-FM labeling analysis in a flow cytometry. We described an arginase-dependent NOS-like activity in L. (L.) amazonensis and its role in the parasite growth. The increased detection of NO production in the mid-stationary and late-stationary growth phases of La-WT promastigotes could suggest that this production is an important factor to metacyclogenesis triggering. On the other hand, La-arg- showed an earlier increase in NO production compared to La-WT, suggesting that NO production can be arginase-dependent. Interestingly, La-WT and La-arg- axenic amastigotes produced higher levels of NO than those observed in promastigotes. As a conclusion, our work suggested that NOS-like is expressed in Leishmania in the stationary growth phase promastigotes and amastigotes, and could be correlated to metacyclogenesis and amastigotes growth in a dependent way to the internal pool of L-arginine and arginase activity.

  17. Histopathology and immunocytochemical study of type 3 and type 4 complement receptors in the liver and spleen of dogs naturally and experimentally infected with Leishmania (Leishmania chagasi Histopatologia e estudo imunocitoquímico dos receptores do tipo 3 e 4 do complemento no fígado e baço de cães natural e experimentalmente infectados com Leishmaniose Visceral

    Directory of Open Access Journals (Sweden)

    Wagner Luiz Tafuri

    1996-04-01

    Full Text Available The objective of this study was to compare the histopathological changes and expression of CR3 and CR4 in the liver and spleen of dogs naturally and experimentally infected with L. chagasi. The basic histopathological lesions observed mainly in naturally infected dogs were: epithelioid hepatic granulomas, hyperplasia and hypertrophy of Kupffer cells, Malpigui follicles and mononucleated cells of the red pulp of the spleen. Sections from the liver and spleen by immunocytochemistry technique showed the presence of CD11b,cCD 18 antigens in the control and infected animals and no qualitative or quantitative differences in the liver. Nevertheless, CD18 was always increased in the spleen of naturally and experimentally infected dogs. These results indicate that there is a difference in the activaton of CD 18 in both experimental and natural cases of canine visceral leishmaniasis that should play an important role in the immunological response to Leishmania chagasi infection.Os objetivos deste trabalho visaram uma análise comparativa das alterações histopatológicas e da expressão de CR3 e CR4 no fígado e baço de cães natural e experimentalmente infectados com L. chagasi. As lesões histopatológicas fundamentais observadas principalmente nos cães naturalmente infectados foram: os granulomas epitelióides hepáticos, a hiperplasia e a hipertrofia das células de Kupffer, dos folículos de Malpighi e das células mononucleadas da polpa vermelha do baço. Os cortes de fígado e baço corados pela técnica de imunocitoquímica mostraram a presença dos antígenos CD11b,cCD18 nos animais controles e infectados, sem diferenças qualitativas e quantitativas no fígado. Entretanto, no baço dos cães natural e experimentalmente infectados a expressão de CD 18 (subunidade beta2 da molécula comum aos leucócitos foi sempre aumentada. Em leishmaniose a resposta imune celular é considerada a mais importante na resolução da doença. A expressão de CD

  18. Frequency of Drug Resistance Gene Amplification in Clinical Leishmania Strains

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    C. Mary

    2010-01-01

    Full Text Available Experimental studies about Leishmania resistance to metal and antifolates have pointed out that gene amplification is one of the main mechanisms of drug detoxification. Amplified genes code for adenosine triphosphate-dependent transporters (multidrug resistance and P-glycoproteins P, enzymes involved in trypanothione pathway, particularly gamma glutamyl cysteine synthase, and others involved in folates metabolism, such as dihydrofolate reductase and pterine reductase. The aim of this study was to detect and quantify the amplification of these genes in clinical strains of visceral leishmaniasis agents: Leishmania infantum, L. donovani, and L. archibaldi. Relative quantification experiments by means of real-time polymerase chain reaction showed that multidrug resistance gene amplification is the more frequent event. For P-glycoproteins P and dihydrofolate reductase genes, level of amplification was comparable to the level observed after in vitro selection of resistant clones. Gene amplification is therefore a common phenomenon in wild strains concurring to Leishmania genomic plasticity. This finding, which corroborates results of experimental studies, supports a better understanding of metal resistance selection and spreading in endemic areas.

  19. Leishmania-based expression systems.

    Science.gov (United States)

    Taheri, Tahereh; Seyed, Negar; Mizbani, Amir; Rafati, Sima

    2016-09-01

    Production of therapeutic or medical recombinant proteins, such as monoclonal antibodies, proteins, or active enzymes, requires a highly efficient system allowing natural folding and perfect post-translation modifications of the expressed protein. These requirements lead to the generation of a variety of gene expression systems from bacteria to eukaryotes. To achieve the best form of eukaryotic proteins, two factors need to be taken into consideration: choosing a suitable organism to express the protein of interest, and selecting an efficient delivery system. For this reason, the expression of recombinant proteins in eukaryotic nonpathogenic Leishmania parasites is an interesting approach which meets both criteria. Here, new Leishmania-based expression systems are compared with current systems that have long histories in research and industry.

  20. Folate metabolic pathways in Leishmania

    Science.gov (United States)

    Vickers, Tim J.; Beverley, Stephen M.

    2012-01-01

    Trypanosomatid parasitic protozoans of the genus Leishmania are autotrophic for both folate and unconjugated pteridines. Leishmania salvage these metabolites from their mammalian hosts and insect vectors through multiple transporters. Within the parasite, folates are reduced by a bifunctional DHFR (dihydrofolate reductase)-TS (thymidylate synthase) and by a novel PTR1 (pteridine reductase 1), which reduces both folates and unconjugated pteridines. PTR1 can act as a metabolic bypass of DHFR inhibition, reducing the effectiveness of existing antifolate drugs. Leishmania possess a reduced set of folate-dependent metabolic reactions and can salvage many of the key products of folate metabolism from their hosts. For example, they lack purine synthesis, which normally requires 10-formyltetrahydrofolate, and instead rely on a network of purine salvage enzymes. Leishmania elaborate at least three pathways for the synthesis of the key metabolite 5,10-methylene-tetrahydrofolate, required for the synthesis of thymidylate, and for 10-formyltetrahydrofolate, whose presumptive function is for methionyl-tRNAMet formylation required for mitochondrial protein synthesis. Genetic studies have shown that the synthesis of methionine using 5-methyltetrahydrofolate is dispensable, as is the activity of the glycine cleavage complex, probably due to redundancy with serine hydroxymethyltransferase. Although not always essential, the loss of several folate metabolic enzymes results in attenuation or loss of virulence in animal models, and a null DHFR-TS mutant has been used to induce protective immunity. The folate metabolic pathway provides numerous opportunities for targeted chemotherapy, with strong potential for ‘repurposing’ of compounds developed originally for treatment of human cancers or other infectious agents. PMID:22023442

  1. Immunization with Leishmania donovani protein disulfide isomerase DNA construct induces Th1 and Th17 dependent immune response and protection against experimental visceral leishmaniasis in Balb/c mice.

    Science.gov (United States)

    Amit, Ajay; Vijayamahantesh; Dikhit, Manas R; Singh, Ashish Kumar; Kumar, Vikash; Suman, Shashi S; Singh, Ashu; Kumar, Akhilesh; Thakur, Ajit Kumar; Das, Vidyanand Ravi; Das, Pradeep; Bimal, Sanjiva

    2017-02-01

    In the present study, the efficacy of Leishmania donovani protein disulfide isomerase (LdPDI) as a DNA vaccine was evaluated in BALB/C mice. Mice immunized with the LdPDI-DNA construct were found to be the most immuno-reactive, as the construct induced higher T-cell proliferation. The increased T-cell proliferation was associated with a substantial rise in Th1 and Th17+ CD4 cell response and triggered a higher proportion of CD8+ T cells for the release of interferon-gamma along with a reduced splenic parasite load on Days20 and 60 post challenge (PC). Furthermore, the vaccine construct triggered increased interferon (IFN)-γ, interleukin(IL)-17A, and IL-22 release accompanied by decreased extracellular signal-regulated kinases (ERK) 1/2 signaling and increased mitogen-activated protein kinase (MAPK) signaling coinciding with an increase in the amount of nitrite and reactive oxygen species (ROS)in vaccinating the splenocyts. We summarize from our data that the PDI-DNA construct of Leishmania donovani has the potential to elicit protective immunity through the pro-inflammatory cytokines of CD8+ and CD4+(Th1 and Th17) following an intervention in the downstream signaling event of ERK1/2 (probably through p38MAPK signaling). Therefore, the study suggests a new control against visceral leishmaniasis in the future. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Leishmania (Viannia lainsoni: occurrence of intracellular promastigote forms in vivo and in vitro

    Directory of Open Access Journals (Sweden)

    José R Corrêa

    2006-12-01

    Full Text Available Experimental chronic (45-day-old skin lesion in hamster hind foot induced by Leishmania (Viannia lainsoni infection showed the presence of promastigote forms in the tissue, inside parasitophorous vacuoles, as assessed by transmission electron microscopy. Experimental in vitro interaction (24 and 48 h between Leishmania (V.lainsoni and J774-G8 macrophage cells also demonstrated the same profile. This morphological aspect is unusual, since in this parasite genus only amastigote forms have been described as the resistant and obligate intracellular forms.

  3. Morphologic aspects of the Leishmania amazonensis submitted to ionizing radiation; Aspectos morfologicos da Leishmania amazonensis submetida a acao da radiacao ionizante

    Energy Technology Data Exchange (ETDEWEB)

    Bonetti, F.C.; Hiramoto, R.M; Nascimento, N. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Lab. de Biologia Molecular; Paiva, B.; Andrade Junior, H.F. [Sao Paulo Univ., SP (Brazil). Faculdade de Medicina. Inst. de Medicina Tropical

    2002-07-01

    Leishmania amazonensis is a protozoan transmitted by a bite of a sandfly responsible for skin lesions in human and other mammalian hosts, being considered one of the most important endemic Public Health disease. Ionizing radiation shown to be an excellent method to kill these parasites, blocking their growth by nucleic acid (DNA) break, and stopping the respiratory metabolism. In this study, we analyze the effects of ionizing radiation on the morphology of the Leishmania amazonensis and the capacity of infection in experimental model. The radio sterilized parasites maintained their membrane surface preserved while destroyed the other proteins needed to their life, promoting the possible of a new antigenic model. (author)

  4. Serological reactivity of different antigenic preparations of Leishmania (Leishmania amazonensis and the Leishmania braziliensis complex Reatividade sorológica frente a diferentes preparações antigênicas de Leishmania (Leishmania amazonensis e do complexo Leishmania braziliensis

    Directory of Open Access Journals (Sweden)

    Adriano Gomes-Silva

    2008-04-01

    Full Text Available Total antigen from Leishmania (Leishmania amazonensis and isolates from the Leishmania braziliensis complex, along with their respective antigenic fractions obtained by affinity chromatography on concanavalin-A-Sepharose and jacalin-agarose columns evaluated using immunoenzymatic ELISA assay. For this, serum samples from 229 patients were used, grouped as American tegmental leishmaniasis (nº=58, visceral leishmaniasis (nº=28, Chagas disease (nº=49, malaria (nº=32, tuberculosis (nº=13 and healthy volunteers (nº=49. Samples from American tegmentary leishmaniasis showed higher reactivity with antigens isolated from the Leishmania braziliensis complex than with antigens from Leishmania amazonensis (pAntígeno total de Leishmania (Leishmania amazonensis e isolado do complexo Leishmania brazilienis, assim como suas respectivas frações antigênicas obtidas por cromatografia de afinidade em coluna de concanavalina-A ligada a sepharose e Jacalina ligada a agarose foram avaliadas por ensaio imunoenzimático ELISA. Para tanto, foram utilizadas amostras de soros de 229 pacientes agrupadas em leishmaniose tegumentar americana (nº=58, leishmaniose visceral (nº=28, doença de Chagas (nº=49, malaria (nº=32, tuberculose (nº=13 e voluntários saudáveis (nº=49. Houve maior reatividade das amostras de leishmaniose tegumentar americana com a utilização dos antígenos obtidos do isolado do complexo Leishmania braziliensis quando comparado com antígenos de Leishmania amazonensis (p<0,001. Observou-se ainda que a sensibilidade do teste ELISA variou de 60 a 95% entre os antígenos obtidos do isolado do complexo Leishmania braziliensis. Houve acentuada reatividade inespecífica das amostras de soros com a utilização das frações antigênicas ligantes de Concanavalina-A e Jacalina de ambos os complexos Leishmania em comparação aos demais antígenos (p<0,001. Os resultados apresentados no presente trabalho sugerem que a utilização de antígenos hom

  5. Leishmania hijacking of the macrophage intracellular compartments.

    Science.gov (United States)

    Liévin-Le Moal, Vanessa; Loiseau, Philippe M

    2016-02-01

    Leishmania spp., transmitted to humans by the bite of the sandfly vector, are responsible for the three major forms of leishmaniasis, cutaneous, diffuse mucocutaneous and visceral. Leishmania spp. interact with membrane receptors of neutrophils and macrophages. In macrophages, the parasite is internalized within a parasitophorous vacuole and engages in a particular intracellular lifestyle in which the flagellated, motile Leishmania promastigote metacyclic form differentiates into non-motile, metacyclic amastigote form. This phenomenon is induced by Leishmania-triggered events leading to the fusion of the parasitophorous vacuole with vesicular members of the host cell endocytic pathway including recycling endosomes, late endosomes and the endoplasmic reticulum. Maturation of the parasitophorous vacuole leads to the intracellular proliferation of the Leishmania amastigote forms by acquisition of host cell nutrients while escaping host defense responses. © 2015 FEBS.

  6. Characterization of Leishmania (Leishmania) amazonensis promastigotes resistant to pentamidine.

    Science.gov (United States)

    Coelho, Adriano C; Gentil, Luciana G; da Silveira, José Franco; Cotrim, Paulo C

    2008-09-01

    Pentamidine is a second-line agent used in the treatment of leishmaniasis and its mode of action and mechanism of resistance is not well understood. It was previously demonstrated that transfection of promastigotes and amastigotes with the ABC transporter PRP1 gene confers resistance to pentamidine. To further clarify this point, we generated Leishmania amazonensis mutants resistant to pentamidine. Our results indicated that this ABC transporter is not associated with pentamidine resistance in lines generated by drug pressure through amplification or overexpression mechanisms of PRP1 gene.

  7. Leishmania RNA virus: when the host pays the toll

    Science.gov (United States)

    Hartley, Mary-Anne; Ronet, Catherine; Zangger, Haroun; Beverley, Stephen M.; Fasel, Nicolas

    2012-01-01

    The presence of an RNA virus in a South American subgenus of the Leishmania parasite, L. (Viannia), was detected several decades ago but its role in leishmanial virulence and metastasis was only recently described. In Leishmania guyanensis, the nucleic acid of Leishmania RNA virus (LRV1) acts as a potent innate immunogen, eliciting a hyper-inflammatory immune response through toll-like receptor 3 (TLR3). The resultant inflammatory cascade has been shown to increase disease severity, parasite persistence, and perhaps even resistance to anti-leishmanial drugs. Curiously, LRVs were found mostly in clinical isolates prone to infectious metastasis in both their human source and experimental animal model, suggesting an association between the viral hyperpathogen and metastatic complications such as mucocutaneous leishmaniasis (MCL). MCL presents as chronic secondary lesions in the mucosa of the mouth and nose, debilitatingly inflamed and notoriously refractory to treatment. Immunologically, this outcome has many of the same hallmarks associated with the reaction to LRV: production of type 1 interferons, bias toward a chronic Th1 inflammatory state and an impaired ability of host cells to eliminate parasites through oxidative stress. More intriguing, is that the risk of developing MCL is found almost exclusively in infections of the L. (Viannia) subtype, further indication that leishmanial metastasis is caused, at least in part, by a parasitic component. LRV present in this subgenus may contribute to the destructive inflammation of metastatic disease either by acting in concert with other intrinsic “metastatic factors” or by independently preying on host TLR3 hypersensitivity. Because LRV amplifies parasite virulence, its presence may provide a unique target for diagnostic and clinical intervention of metastatic leishmaniasis. Taking examples from other members of the Totiviridae virus family, this paper reviews the benefits and costs of endosymbiosis, specifically

  8. Th1-stimulatory polyproteins of soluble Leishmania donovani promastigotes ranging from 89.9 to 97.1 kDa offers long-lasting protection against experimental visceral leishmaniasis.

    Science.gov (United States)

    Kumari, Shraddha; Samant, Mukesh; Misra, Pragya; Khare, Prashant; Sisodia, Brijesh; Shasany, Ajit K; Dube, Anuradha

    2008-10-23

    Our earlier studies identified a fraction (F2) of Leishmania donovani soluble promastigote antigen belonging to 97.4-68 kDa for its ability to stimulate Th1-type cellular responses in cured visceral leishmaniasis (VL) patients as well as in cured hamsters. A further fractionation of F2-fraction into seven subfractions (F2.1-F2.7) and re-assessment for their immunostimulatory responses revealed that out of these, only four (F2.4-F2.7) belonging to 89.9-97.1 kDa, stimulated remarkable Th1-type cellular responses either individually or in a pooled form (P4-7). In this study these potential subfractions were further assessed for their prophylactic potential in combination with BCG against L. donovani challenge in hamsters. Optimum parasite inhibition ( approximately 99%) was obtained in hamsters vaccinated with pooled subfractions and they survived for 1 year. The protection was further supported by remarkable lymphoproliferative, IFN-gamma and IL-12 responses along with profound delayed type hypersensitivity and increased levels of Leishmania-specific IgG2 antibody as observed on days 45, 90 and 120 post-challenge suggesting that a successful subunit vaccine against VL may require multiple Th1-immunostimulatory proteins. MALDI-TOF-MS/MS analysis of these subfractions further revealed that of the 19 identified immunostimulatory proteins, Elongation factor-2, p45, Heat shock protein-70/83, Aldolase, Enolase, Triosephosphate isomerase, Disulfideisomerase and Calreticulin were the major ones in these subfractions.

  9. The action of ionizing radiation on the morphology, physiology and growth of Leishmania Amazonensis, with evaluation of their immunogenic power in experimental models; Acao da radiacao ionizante sobre a morfologia, fisiologia e crescimento da Leishmania amazonensis, com avaliacao de seu poder imunogenico em modelos experimentais

    Energy Technology Data Exchange (ETDEWEB)

    Bonetti, Franco Claudio

    2002-07-01

    Leishmaniasis is a disease which affects thousands of people in the Tropical regions around the world, is caused by a protozoan of the genus Leishmania spp., with urban and wild mammals acting as reservoirs. In the mammal host, the amastigote form of the parasite infects and multiplies into macrophages. Treatments for leishmaniasis have a high cost and are long lasting, frequently resulting in therapy interruption. This procedure culminates with a selection of resistant parasite strains, inducing tolerance to the therapy. Either the control of vectors or the mammal host are difficult due the social and economic implications. Thus, the search for alternatives treatments against these protozoans have been stimulated. The gamma radiation ({sup 60}CO) shown to be an efficient toll to kill these parasites maintaining their immunogenicity. Cellular viability, Electronically microscopy and Multiplex-PCR techniques showed that, after irradiation, the parasites had their growth inhibited by cytoplasmatic and nucleic material disorganisation, appointing the gamma radiation as important in terms of immunogens improvement. (author)

  10. Coadministration of the Three Antigenic Leishmania infantum Poly (A) Binding Proteins as a DNA Vaccine Induces Protection against Leishmania major Infection in BALB/c Mice.

    Science.gov (United States)

    Soto, Manuel; Corvo, Laura; Garde, Esther; Ramírez, Laura; Iniesta, Virginia; Bonay, Pedro; Gómez-Nieto, Carlos; González, Víctor M; Martín, M Elena; Alonso, Carlos; Coelho, Eduardo A F; Barral, Aldina; Barral-Netto, Manoel; Iborra, Salvador

    2015-05-01

    Highly conserved intracellular proteins from Leishmania have been described as antigens in natural and experimental infected mammals. The present study aimed to evaluate the antigenicity and prophylactic properties of the Leishmania infantum Poly (A) binding proteins (LiPABPs). Three different members of the LiPABP family have been described. Recombinant tools based on these proteins were constructed: recombinant proteins and DNA vaccines. The three recombinant proteins were employed for coating ELISA plates. Sera from human and canine patients of visceral leishmaniasis and human patients of mucosal leishmaniasis recognized the three LiPABPs. In addition, the protective efficacy of a DNA vaccine based on the combination of the three Leishmania PABPs has been tested in a model of progressive murine leishmaniasis: BALB/c mice infected with Leishmania major. The induction of a Th1-like response against the LiPABP family by genetic vaccination was able to down-regulate the IL-10 predominant responses elicited by parasite LiPABPs after infection in this murine model. This modulation resulted in a partial protection against L. major infection. LiPABP vaccinated mice showed a reduction on the pathology that was accompanied by a decrease in parasite burdens, in antibody titers against Leishmania antigens and in the IL-4 and IL-10 parasite-specific mediated responses in comparison to control mice groups immunized with saline or with the non-recombinant plasmid. The results presented here demonstrate for the first time the prophylactic properties of a new family of Leishmania antigenic intracellular proteins, the LiPABPs. The redirection of the immune response elicited against the LiPABP family (from IL-10 towards IFN-γ mediated responses) by genetic vaccination was able to induce a partial protection against the development of the disease in a highly susceptible murine model of leishmaniasis.

  11. Novo alelo do gene A2 descrito em Leishmania (Leishmania) infantum chagasi

    OpenAIRE

    Trícia Maria Ferreira de Sousa Oliveira; Elton José Rosas de Vasconcelos; Andréa Cristina Higa Nakaghi; Tânia Paula Aquino Defina; Márcia Mariza Gomes Jusi; Cristiane Divan Baldani; Ângela Kaysel Cruz; Rosangela Zacarias Machado

    2011-01-01

    Visceral leishmaniasis (VL) is a widely spread zoonotic disease. In Brazil the disease is caused by Leishmania (Leishmania) infantum chagasi. Peridomestic sandflies acquire the etiological agent by feeding on blood of infected reservoir animals, such as dogs or wildlife. The disease is endemic in Brazil and epidemic foci have been reported in densely populated cities all over the country. Many clinical features of Leishmania infection are related to the host-parasite relationship, and many ca...

  12. Methodology optimizing SAGE library tag-to-gene mapping: application to Leishmania.

    Science.gov (United States)

    Smandi, Sondos; Guerfali, Fatma Z; Farhat, Mohamed; Ben-Aissa, Khadija; Laouini, Dhafer; Guizani-Tabbane, Lamia; Dellagi, Koussay; Benkahla, Alia

    2012-01-27

    Leishmaniasis are widespread parasitic-diseases with an urgent need for more active and less toxic drugs and for effective vaccines. Understanding the biology of the parasite especially in the context of host parasite interaction is a crucial step towards such improvements in therapy and control. Several experimental approaches including SAGE (Serial analysis of gene expression) have been developed in order to investigate the parasite transcriptome organisation and plasticity. Usual SAGE tag-to-gene mapping techniques are inadequate because almost all tags are normally located in the 3'-UTR outside the CDS, whereas most information available for Leishmania transcripts is restricted to the CDS predictions. The aim of this work is to optimize a SAGE libraries tag-to-gene mapping technique and to show how this development improves the understanding of Leishmania transcriptome. The in silico method implemented herein was based on mapping the tags to Leishmania genome using BLAST then mapping the tags to their gene using a data-driven probability distribution. This optimized tag-to-gene mappings improved the knowledge of Leishmania genome structure and transcription. It allowed analyzing the expression of a maximal number of Leishmania genes, the delimitation of the 3' UTR of 478 genes and the identification of biological processes that are differentially modulated during the promastigote to amastigote differentiation. The developed method optimizes the assignment of SAGE tags in trypanosomatidae genomes as well as in any genome having polycistronic transcription and small intergenic regions.

  13. Methodology optimizing SAGE library tag-to-gene mapping: application to Leishmania

    Directory of Open Access Journals (Sweden)

    Smandi Sondos

    2012-01-01

    Full Text Available Abstract Background Leishmaniasis are widespread parasitic-diseases with an urgent need for more active and less toxic drugs and for effective vaccines. Understanding the biology of the parasite especially in the context of host parasite interaction is a crucial step towards such improvements in therapy and control. Several experimental approaches including SAGE (Serial analysis of gene expression have been developed in order to investigate the parasite transcriptome organisation and plasticity. Usual SAGE tag-to-gene mapping techniques are inadequate because almost all tags are normally located in the 3'-UTR outside the CDS, whereas most information available for Leishmania transcripts is restricted to the CDS predictions. The aim of this work is to optimize a SAGE libraries tag-to-gene mapping technique and to show how this development improves the understanding of Leishmania transcriptome. Findings The in silico method implemented herein was based on mapping the tags to Leishmania genome using BLAST then mapping the tags to their gene using a data-driven probability distribution. This optimized tag-to-gene mappings improved the knowledge of Leishmania genome structure and transcription. It allowed analyzing the expression of a maximal number of Leishmania genes, the delimitation of the 3' UTR of 478 genes and the identification of biological processes that are differentially modulated during the promastigote to amastigote differentiation. Conclusion The developed method optimizes the assignment of SAGE tags in trypanosomatidae genomes as well as in any genome having polycistronic transcription and small intergenic regions.

  14. Evidence for a neotropical origin of Leishmania

    Directory of Open Access Journals (Sweden)

    HA Noyes

    2000-08-01

    Full Text Available Contradictory biogeographic hypotheses for either a Neotropical or a Palaearctic origin of the genus Leishmania have been proposed. Hypotheses constructed on the basis of biogeographic data must be tested against an independent dataset and cannot be supported by biogeographic data alone. In the absence of a fossil record for the Leishmania these two hypotheses were tested against a combined dataset of sequences from the DNA polymerase A catalytic subunit and the RNA polymerase II largest subunit. The phylogeny obtained provided considerable support for a Neotropical origin of the genus Leishmania and leads us to reject the hypothesis for a Palaearctic origin.

  15. Absence of leishmania in Guianan bats.

    Science.gov (United States)

    Rotureau, Brice; Catzeflis, François; Carme, Bernard

    2006-02-01

    Studying the ecology of Leishmania parasites is essential for understanding and controlling the epidemiology of the diseases they cause. Despite their abundance and diversity in neotropical forests, few studies have been conducted to investigate the potential involvement of Chiroptera in the Leishmania pathogenic complexes. However, phlebotomine sand flies are known to colonize the same anthropized habitat, are attracted to bats, and are able to transmit trypanosomatids. Thus, 216 bats representing 29 species were sampled in the field in different primary and secondary forests of French Guiana where human cutaneous leishmaniases have been reported, together with 62 non-volant mammals. A series of 411 tissue samples representing 47 mammalian species were cultured and screened for the presence of Leishmania spp. by a genus-specific polymerase chain reaction. All 278 individuals surveyed were negative. Thus, bats do not appear to be involved in the Leishmania parasitic cycles in the Guyanas.

  16. Distinct Macrophage Fates after in vitro Infection with Different Species of Leishmania: Induction of Apoptosis by Leishmania (Leishmania) amazonensis, but Not by Leishmania (Viannia) guyanensis: e0141196

    National Research Council Canada - National Science Library

    Jarina Pena DaMata; Bárbara Pinheiro Mendes; Kátia Maciel-Lima; Cristiane Alves Silva Menezes; Walderez Ornelas Dutra; Lirlândia Pires Sousa; Maria Fátima Horta

    2015-01-01

      Leishmania is an intracellular parasite in vertebrate hosts, including man. During infection, amastigotes replicate inside macrophages and are transmitted to healthy cells, leading to amplification of the infection...

  17. Phylogenomic reconstruction supports supercontinent origins for Leishmania.

    Science.gov (United States)

    Harkins, Kelly M; Schwartz, Rachel S; Cartwright, Reed A; Stone, Anne C

    2016-03-01

    Leishmania, a genus of parasites transmitted to human hosts and mammalian/reptilian reservoirs by an insect vector, is the causative agent of the human disease complex leishmaniasis. The evolutionary relationships within the genus Leishmania and its origins are the source of ongoing debate, reflected in conflicting phylogenetic and biogeographic reconstructions. This study employs a recently described bioinformatics method, SISRS, to identify over 200,000 informative sites across the genome from newly sequenced and publicly available Leishmania data. This dataset is used to reconstruct the evolutionary relationships of this genus. Additionally, we constructed a large multi-gene dataset, using it to reconstruct the phylogeny and estimate divergence dates for species. We conclude that the genus Leishmania evolved at least 90-100 million years ago, supporting a modified version of the Multiple Origins hypothesis that we call the Supercontinent hypothesis. According to this scenario, separate Leishmania clades emerged prior to, and during, the breakup of Gondwana. Additionally, we confirm that reptile-infecting Leishmania are derived from mammalian forms and that the species that infect porcupines and sloths form a clade long separated from other species. Finally, we firmly place the guinea-pig infecting species, Leishmaniaenriettii, the globally dispersed Leishmaniasiamensis, and the newly identified Australian species from a kangaroo, as sibling species whose distribution arises from the ancient connection between Australia, Antarctica, and South America. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Ocular alterations in dogs naturally infected by Leishmania (Leishmania chagasi Alterações oculares em cães infectados naturalmente por Leishmania (Leishmania chagasi

    Directory of Open Access Journals (Sweden)

    F.L.C. Brito

    2006-10-01

    Full Text Available Ocular conditions, anti-Leishmania antibodies and total protein of the aqueous humor were studied in dogs naturally infected by Leishmania (Leishmania chagasi. Fifty dogs were analyzed and assigned into two groups of 25 animals each. All animals were submitted to routine ophthalmic exam. Results showed that 76% of the affected animals presented ocular signs, being uveitis the predominant. The mean of total protein in the aqueous humor of animals with uveitis was higher (PEstudaram-se as condições oculares, os anticorpos anti-Leishmania e os valores de proteína total no humor aquoso de cães infectados naturalmente por Leishmania (Leishmania chagasi. Analisaram-se 50 cães, divididos em dois grupos de 25 animais. Todos os animais foram submetidos a exame oftálmico rotineiro. Os resultados mostraram que 76% dos cães infectados apresentaram sinais oculares, sendo a uveíte a alteração predominante. A média de proteína total no humor aquoso dos animais com uveíte foi maior (P<0,05, que a dos animais com outros sinais oculares ou sem qualquer sinal. Os valores de anticorpos anti-L. chagasi obtidos no plasma foram estatisticamente superiores aos encontrados no humor aquoso (P<0,05.

  19. Effect of glycosphingolipids purified from Leishmania (Leishmania) amazonensis amastigotes on human peripheral lymphocytes

    OpenAIRE

    Giorgio, S; Santos, MRM; Straus,AH; Takahashi, HK; Barbieri, CU

    2003-01-01

    The effect of purified glycosphingolipids from Leishmania (Leishmania) amazonensis on human lymphoproliferation, on expression of human lymphocyte and monocyte markers (CD3, CD4, CD8, CD14, CD19, and CD45), and on lymphocyte protein kinase C activity was analyzed.

  20. A novel A2 allele found in Leishmania (Leishmania infantum chagasi Novo alelo do gene A2 descrito em Leishmania (Leishmania infantum chagasi

    Directory of Open Access Journals (Sweden)

    Trícia Maria Ferreira de Sousa Oliveira

    2011-03-01

    Full Text Available Visceral leishmaniasis (VL is a widely spread zoonotic disease. In Brazil the disease is caused by Leishmania (Leishmania infantum chagasi. Peridomestic sandflies acquire the etiological agent by feeding on blood of infected reservoir animals, such as dogs or wildlife. The disease is endemic in Brazil and epidemic foci have been reported in densely populated cities all over the country. Many clinical features of Leishmania infection are related to the host-parasite relationship, and many candidate virulence factors in parasites that cause VL have been studied such as A2 genes. The A2 gene was first isolated in 1994 and then in 2005 three new alleles were described in Leishmania (Leishmania infantum. In the present study we amplified by polymerase chain reaction (PCR and sequenced the A2 gene from the genome of a clonal population of L. (L. infantum chagasi VL parasites. The L. (L. infantum chagasi A2 gene was amplified, cloned, and sequenced in. The amplified fragment showed approximately 90% similarity with another A2 allele amplified in Leishmania (Leishmania donovani and in L.(L. infantum described in literature. However, nucleotide translation shows differences in protein amino acid sequence, which may be essential to determine the variability of A2 genes in the species of the L. (L. donovani complex and represents an additional tool to help understanding the role this gene family may have in establishing virulence and immunity in visceral leishmaniasis. This knowledge is important for the development of more accurate diagnostic tests and effective tools for disease control.A leishmaniose visceral (LV é uma zoonose amplamente disseminada, causada no Brasil pela Leishmania (Leishmania infantum chagasi. Flebotomíneos vetores adquirem o agente etiológico, alimentando-se do sangue de animais contaminados, como cachorros ou animais selvagens. A doença é endêmica no Brasil, e focos de epidemia são relatados em cidades densamente povoadas

  1. Leishmania

    Indian Academy of Sciences (India)

    NII

    Sand Fly. Cutaneous Leishmaniasis. L. tropica. Muco-cutaneous. Visceral. PKDL. Detection. L. brazillensis &. L. mexicana. L. Donovani (Kala-azar). & L.infantum. Detection of parasite from splenic aspiration or from bone marrow puncture. Treatment: Pentavalent antimonial like sodium stibogluconate, meglumine: Very toxic ...

  2. In vivo and in vitro phagocytosis of Leishmania (Leishmania) amazonensis promastigotes by B‐1 cells

    National Research Council Canada - National Science Library

    Geraldo, M. M; Costa, C. R; Barbosa, F. M. C; Vivanco, B. C; Gonzaga, W.F. K. M; Novaes e Brito, R. R; Popi, A. F; Lopes, J. D; Xander, P

    2016-01-01

    Leishmaniasis is caused by Leishmania parasites that infect several cell types. The promastigote stage of Leishmania is internalized by phagocytic cells and transformed into the obligate intracellular amastigote form. B...

  3. Screening for Inhibitors of Essential Leishmania Glucose Transporters

    Science.gov (United States)

    2013-07-01

    Leishmania Glucose Transporters PRINCIPAL INVESTIGATOR: Scott M. Landfear, Ph.D. CONTRACTING ORGANIZATION: Oregon Health & Science...COVERED 1 July 2009- 30 June 2013 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Screening for Inhibitors of Essential Leishmania Glucose Transporters 5b...The objective of this project was to identify compounds that selectively inhibit the essential Leishmania glucose transporters and could hence serve

  4. The proliferation potential of promastigotes of the main Leishmania species of the old world in NNN culture medium prepared using blood of four different mammals.

    Science.gov (United States)

    Ladopoulos, Theodoros; Ntais, Pantelis; Tsirigotakis, Nikolaos; Dokianakis, Emmanouil; Antoniou, Maria

    2015-10-01

    The efficacy of the in vitro cultivation of promastigotes of four Leishmania spp. was tested in the biphasic Novy-MacNeal-Nicolle (NNN) medium prepared using blood from different animals (horse, donkey, goat and sheep). The aim was to test which NNN preparation gave the best yield in the shortest time for different parasite species, in order to obtain a large crop of promastigotes for experimental work and for antigen preparation. Promastigotes of Leishmania infantum, Leishmania donovani, Leishmania tropica and Leishmania major, the four main parasite species occurring in the old world, were defrosted from -80 °C and placed, at equal numbers, in the 4 different NNN preparations. At the end of the 7th day, the NNN medium using horse blood produced the greatest number of promastigotes for all Leishmania spp. tested, whilst goat blood proved the poorest medium, providing culture results only for L. infantum. This finding may be explained by the fact that Leishmania is a nicotinamide adenine dinucleotide (NAD) auxotroph and horse erythrocytes support NAD-dependent microorganisms. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Regulation of immunity during visceral Leishmania infection.

    Science.gov (United States)

    Rodrigues, Vasco; Cordeiro-da-Silva, Anabela; Laforge, Mireille; Silvestre, Ricardo; Estaquier, Jérôme

    2016-03-01

    Unicellular eukaryotes of the genus Leishmania are collectively responsible for a heterogeneous group of diseases known as leishmaniasis. The visceral form of leishmaniasis, caused by L. donovani or L. infantum, is a devastating condition, claiming 20,000 to 40,000 lives annually, with particular incidence in some of the poorest regions of the world. Immunity to Leishmania depends on the development of protective type I immune responses capable of activating infected phagocytes to kill intracellular amastigotes. However, despite the induction of protective responses, disease progresses due to a multitude of factors that impede an optimal response. These include the action of suppressive cytokines, exhaustion of specific T cells, loss of lymphoid tissue architecture and a defective humoral response. We will review how these responses are orchestrated during the course of infection, including both early and chronic stages, focusing on the spleen and the liver, which are the main target organs of visceral Leishmania in the host. A comprehensive understanding of the immune events that occur during visceral Leishmania infection is crucial for the implementation of immunotherapeutic approaches that complement the current anti-Leishmania chemotherapy and the development of effective vaccines to prevent disease.

  6. The efficacy of 2-nitrovinylfuran derivatives against Leishmania in vitro and in vivo

    Directory of Open Access Journals (Sweden)

    Sergio Sifontes-Rodríguez

    2015-04-01

    Full Text Available Despite recent advances in the treatment of some forms of leishmaniasis, the available drugs are still far from ideal due to inefficacy, parasite resistance, toxicity and cost. The wide-spectrum antimicrobial activity of 2-nitrovinylfuran compounds has been described, as has their activity against Trichomonas vaginalis and other protozoa. Thus, the aim of this study was to test the antileishmanial activities of six 2-nitrovinylfurans in vitro and in a murine model of leishmaniasis. Minimum parasiticide concentration (MPC and 50% inhibitory concentration (IC50 values for these compounds against the promastigotes of Leishmania amazonensis, Leishmania infantum and Leishmania braziliensis were determined, as were the efficacies of two selected compounds in an experimental model of cutaneous leishmaniasis (CL caused by L. amazonensis in BALB/c mice. All of the compounds were active against the promastigotes of the three Leishmania species tested. IC50 and MPC values were in the ranges of 0.8-4.7 µM and 1.7-32 µM, respectively. The compounds 2-bromo-5-(2-bromo-2-nitrovinyl-furan (furvina and 2-bromo-5-(2-methyl-2-nitrovinyl-furan (UC245 also reduced lesion growth in vivo at a magnitude comparable to or higher than that achieved by amphotericin B treatment. The results demonstrate the potential of this class of compounds as antileishmanial agents and support the clinical testing of Dermofural(r (a furvina-containing antifungal ointment for the treatment of CL.

  7. Atypical mucocutaneous involvement with Leishmania donovani.

    Science.gov (United States)

    Pulimood, S A; Rupali, P; Ajjampur, S S R; Thomas, M; Mehrotra, S; Sundar, S

    2012-01-01

    Mucocutaneous leishmaniasis has rarely been reported from India. The usual causative organisms of this infection are Leishmania braziliensis and L. tropica. Another species, L. donovani, which usually causes visceral leishmaniasis, has recently been reported to cause mucocutaneous disease in a few patients from Sri Lanka. We report two patients who had undiagnosed chronic skin lesions for several years. Skin biopsies revealed Leishmania and the species was characterized as L. donovani in both patients. There was considerable improvement in the skin lesions following treatment with liposomal amphotericin B. Copyright 2012, NMJI.

  8. Reatividade sorológica frente a diferentes preparações antigênicas de Leishmania (Leishmania) amazonensis e do complexo Leishmania braziliensis

    OpenAIRE

    Adriano Gomes-Silva; Maria Aparecida de Souza; Sandra Regina Afonso-Cardoso; Lívia Resende Andrade; Reynaldo Dietze; Elenice Lemos; Alejandro Belli; Silvio Favoreto Júnior; Marcelo Simão Ferreira

    2008-01-01

    Total antigen from Leishmania (Leishmania) amazonensis and isolates from the Leishmania braziliensis complex, along with their respective antigenic fractions obtained by affinity chromatography on concanavalin-A-Sepharose and jacalin-agarose columns evaluated using immunoenzymatic ELISA assay. For this, serum samples from 229 patients were used, grouped as American tegmental leishmaniasis (nº=58), visceral leishmaniasis (nº=28), Chagas disease (nº=49), malaria (nº=32), tuberculosis (nº=13) an...

  9. Real-time in vivo green fluorescent protein imaging of a murine leishmaniasis model as a new tool for Leishmania vaccine and drug discovery.

    Science.gov (United States)

    Mehta, Sanjay R; Huang, Robert; Yang, Meng; Zhang, Xing-Quan; Kolli, Bala; Chang, Kwang-Poo; Hoffman, Robert M; Goto, Yasuyuki; Badaro, Roberto; Schooley, Robert T

    2008-12-01

    Leishmania species are obligate intracellular protozoan parasites that cause a broad spectrum of clinical diseases in mammalian hosts. The most frequently used approach to quantify parasites in murine model systems is based on thickness measurements of the footpad or ear after experimental infection. To overcome the limitations of this method, we used a Leishmania mutant episomally transfected with enhanced green fluorescent protein, enabling in vivo real-time whole-body fluorescence imaging, to follow the progression of Leishmania infection in parasitized tissues. Fluorescence correlated with the number of Leishmania parasites in the tissue and demonstrated the real-time efficacy of a therapeutic vaccine. This approach provides several substantial advantages over currently available animal model systems for the in vivo study of immunopathogenesis, prevention, and therapy of leishmaniasis. These include improvements in sensitivity and the ability to acquire real-time data on progression and spread of the infection.

  10. Elongation factor-2, a Th1 stimulatory protein of Leishmania donovani, generates strong IFN-γ and IL-12 response in cured Leishmania-infected patients/hamsters and protects hamsters against Leishmania challenge.

    Science.gov (United States)

    Kushawaha, Pramod K; Gupta, Reema; Sundar, Shyam; Sahasrabuddhe, Amogh A; Dube, Anuradha

    2011-12-15

    In visceral leishmaniasis, Th1 types of immune responses correlate with recovery from and resistance to disease, and resolution of infection results in lifelong immunity against the disease. Leishmanial Ags that elicit proliferative and cytokine responses in PBMCs from cured/exposed/Leishmania patients have been characterized through proteomic approaches, and elongation factor-2 is identified as one of the potent immunostimulatory proteins. In this study, we report the cloning and expression of Leishmania donovani elongation factor-2 protein (LelF-2) and its immunogenicity in PBMCs of cured/exposed Leishmania-infected patients and hamsters (Mesocricetus auratus). Leishmania-infected cured/exposed patients and hamsters exhibited significantly higher proliferative responses to recombinant Lelf-2 (rLelF-2) than those with L. donovani-infected hosts. The soluble L. donovani Ag stimulated PBMCs of cured/exposed and Leishmania patients to produce a mixed Thl/Th2-type cytokine profile, whereas rLelF-2 stimulated the production of IFN-γ, IL-12, and TNF-α but not IL-4 or IL-10. Further, rLelF-2 downregulated LPS-induced IL-10 as well as soluble L. donovani Ag-induced IL-4 production by Leishmania patient PBMCs. The immunogenicity of rLelF-2 was also checked in hamsters in which rLelF-2 generates strong IL-12- and IFN-γ-mediated Th1 immune response. This was further supported by a remarkable increase in IgG2 Ab level. We further demonstrated that rLelF-2 was able to provide considerable protection (∼65%) to hamsters against L. donovani challenge. The efficacy was supported by the increased inducible NO synthase mRNA transcript and Th1-type cytokines IFN-γ, IL-12, and TNF-α and downregulation of IL-4, IL-10, and TGF-β. Hence, it is inferred that rLelF-2 elicits a Th1 type of immune response exclusively and confers considerable protection against experimental visceral leishmaniasis.

  11. Testing of four Leishmania vaccine candidates in a mouse model of infection with Leishmania (Viannia) braziliensis, the main causative agent of cutaneous leishmaniasis in the New World.

    Science.gov (United States)

    Salay, G; Dorta, M L; Santos, N M; Mortara, R A; Brodskyn, C; Oliveira, C I; Barbiéri, C L; Rodrigues, M M

    2007-09-01

    We evaluated whether four recombinant antigens previously used for vaccination against experimental infection with Leishmania (Leishmania) major could also induce protective immunity against a challenge with Leishmania (Viannia) braziliensis, the species responsible for 90% of the 28,712 annual cases of cutaneous and mucocutaneous leishmaniasis recorded in Brazil during the year of 2004. Initially, we isolated the homolog genes encoding four L. (V.) braziliensis antigens: (i) homologue of receptor for activated C kinase, (ii) thiol-specific antioxidant, (iii) Leishmania elongation and initiation factor, and (iv) L. (L.) major stress-inducible protein 1. At the deduced amino acid level, all four open reading frames had a high degree of identity with the previously described genes of L. (L.) major being expressed on promastigotes and amastigotes of L. (V.) braziliensis. These genes were inserted into the vector pcDNA3 or expressed as bacterial recombinant proteins. After immunization with recombinant plasmids or proteins, BALB/c mice generated specific antibody or cell-mediated immune responses (gamma interferon production). After an intradermal challenge with L. (V.) braziliensis infective promastigotes, no significant reduction on the lesions was detected. We conclude that the protective immunity afforded by these four vaccine candidates against experimental cutaneous leishmaniasis caused by L. (L.) major could not be reproduced against a challenge with L. (V.) braziliensis. Although negative, we consider our results important since they suggest that studies aimed at the development of an effective vaccine against L. (V.) braziliensis, the main causative agent of cutaneous leishmaniasis in the New World, should be redirected toward distinct antigens or different vaccination strategies.

  12. High Resolution Melting Analysis Targeting hsp70 as a Fast and Efficient Method for the Discrimination of Leishmania Species.

    Science.gov (United States)

    Zampieri, Ricardo Andrade; Laranjeira-Silva, Maria Fernanda; Muxel, Sandra Marcia; Stocco de Lima, Ana Carolina; Shaw, Jeffrey Jon; Floeter-Winter, Lucile Maria

    2016-02-01

    Protozoan parasites of the genus Leishmania cause a large spectrum of clinical manifestations known as Leishmaniases. These diseases are increasingly important public health problems in many countries both within and outside endemic regions. Thus, an accurate differential diagnosis is extremely relevant for understanding epidemiological profiles and for the administration of the best therapeutic protocol. Exploring the High Resolution Melting (HRM) dissociation profiles of two amplicons using real time polymerase chain reaction (real-time PCR) targeting heat-shock protein 70 coding gene (hsp70) revealed differences that allowed the discrimination of genomic DNA samples of eight Leishmania species found in the Americas, including Leishmania (Leishmania) infantum chagasi, L. (L.) amazonensis, L. (L.) mexicana, L. (Viannia) lainsoni, L. (V.) braziliensis, L. (V.) guyanensis, L. (V.) naiffi and L. (V.) shawi, and three species found in Eurasia and Africa, including L. (L.) tropica, L. (L.) donovani and L. (L.) major. In addition, we tested DNA samples obtained from standard promastigote culture, naturally infected phlebotomines, experimentally infected mice and clinical human samples to validate the proposed protocol. HRM analysis of hsp70 amplicons is a fast and robust strategy that allowed for the detection and discrimination of all Leishmania species responsible for the Leishmaniases in Brazil and Eurasia/Africa with high sensitivity and accuracy. This method could detect less than one parasite per reaction, even in the presence of host DNA.

  13. Generation of growth arrested Leishmania amastigotes: a tool to develop live attenuated vaccine candidates against visceral leishmaniasis.

    Science.gov (United States)

    Selvapandiyan, Angamuthu; Dey, Ranadhir; Gannavaram, Sreenivas; Solanki, Sumit; Salotra, Poonam; Nakhasi, Hira L

    2014-06-30

    Visceral leishmaniasis (VL) is fatal if not treated and is prevalent widely in the tropical and sub-tropical regions of world. VL is caused by the protozoan parasite Leishmania donovani or Leishmania infantum. Although several second generation vaccines have been licensed to protect dogs against VL, there are no effective vaccines against human VL [1]. Since people cured of leishmaniasis develop lifelong protection, development of live attenuated Leishmania parasites as vaccines, which can have controlled infection, may be a close surrogate to leishmanization. This can be achieved by deletion of genes involved in the regulation of growth and/or virulence of the parasite. Such mutant parasites generally do not revert to virulence in animal models even under conditions of induced immune suppression due to complete deletion of the essential gene(s). In the Leishmania life cycle, the intracellular amastigote form is the virulent form and causes disease in the mammalian hosts. We developed centrin gene deleted L. donovani parasites that displayed attenuated growth only in the amastigote stage and were found safe and efficacious against virulent challenge in the experimental animal models. Thus, targeting genes differentially expressed in the amastigote stage would potentially attenuate only the amastigote stage and hence controlled infectivity may be effective in developing immunity. This review lays out the strategies for attenuation of the growth of the amastigote form of Leishmania for use as live vaccine against leishmaniasis, with a focus on visceral leishmaniasis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. High Resolution Melting Analysis Targeting hsp70 as a Fast and Efficient Method for the Discrimination of Leishmania Species.

    Directory of Open Access Journals (Sweden)

    Ricardo Andrade Zampieri

    2016-02-01

    Full Text Available Protozoan parasites of the genus Leishmania cause a large spectrum of clinical manifestations known as Leishmaniases. These diseases are increasingly important public health problems in many countries both within and outside endemic regions. Thus, an accurate differential diagnosis is extremely relevant for understanding epidemiological profiles and for the administration of the best therapeutic protocol.Exploring the High Resolution Melting (HRM dissociation profiles of two amplicons using real time polymerase chain reaction (real-time PCR targeting heat-shock protein 70 coding gene (hsp70 revealed differences that allowed the discrimination of genomic DNA samples of eight Leishmania species found in the Americas, including Leishmania (Leishmania infantum chagasi, L. (L. amazonensis, L. (L. mexicana, L. (Viannia lainsoni, L. (V. braziliensis, L. (V. guyanensis, L. (V. naiffi and L. (V. shawi, and three species found in Eurasia and Africa, including L. (L. tropica, L. (L. donovani and L. (L. major. In addition, we tested DNA samples obtained from standard promastigote culture, naturally infected phlebotomines, experimentally infected mice and clinical human samples to validate the proposed protocol.HRM analysis of hsp70 amplicons is a fast and robust strategy that allowed for the detection and discrimination of all Leishmania species responsible for the Leishmaniases in Brazil and Eurasia/Africa with high sensitivity and accuracy. This method could detect less than one parasite per reaction, even in the presence of host DNA.

  15. Tentativa de transmissão da Leishmania donovani pela picada do Lutzomyia longipalpis entre cães

    Directory of Open Access Journals (Sweden)

    Ítalo A. Sherlock

    1972-02-01

    Full Text Available Os Autores apresentam dados sôbre tentativas de transmissão experimental da Leishmania donovani pela picada de Lutzomyia longipalpis entre cães. Dois cães jovens sadios foram picados respectivamente por dois e sete flebótomos ricamente infectados e não adquiriram leishmaniose.

  16. Interleukin-4 and interferon-¿ production by Leishmania stimulated peripheral blood mononuclear cells from nonexposed individuals

    DEFF Research Database (Denmark)

    Kurtzhals, J A; Kemp, M; Poulsen, L K

    1995-01-01

    Leishmania reactive CD4+ T cells could be demonstrated. The cells from different individuals showed different patterns of IFN-gamma and/or IL-4 production upon antigenic stimulation. In experimental leishmaniasis the early balance between IFN-gamma and IL-4 is important for the clinical outcome. Our findings...

  17. First Cases of Cutaneous Leishmaniasis Caused by Leishmania (Viannia) naiffi Infection in Surinam

    NARCIS (Netherlands)

    van Thiel, Pieter-Paul A. M.; van Gool, Tom; Kager, Piet A.; Bart, Aldert

    2010-01-01

    Cutaneous leishmaniasis in Surinam is generally caused by infection by Leishmania guyanensis. We report three cases of infection with Leishmania (Viannia) naiffi, a Leishmania species not described from Surinam before. Treatment with pentamidine proved to be effective

  18. First Cases of Cutaneous Leishmaniasis Caused by Leishmania (Viannia) naiffi Infection in Surinam

    Science.gov (United States)

    van Thiel, Pieter-Paul A. M.; van Gool, Tom; Kager, Piet A.; Bart, Aldert

    2010-01-01

    Cutaneous leishmaniasis in Surinam is generally caused by infection by Leishmania guyanensis. We report three cases of infection with Leishmania (Viannia) naiffi, a Leishmania species not described from Surinam before. Treatment with pentamidine proved to be effective. PMID:20348504

  19. [Taxonomic problems of the Leishmania of reptiles].

    Science.gov (United States)

    Ovezmukhammedov, A; Saf'ianova, V M

    1989-01-01

    The history of description and state of knowledge of 17 species and 40 not identified to species forms of Leishmania, described from reptiles of the world, are traced. It is suggested to retain 10 species and 3 forms of Leishmania in the list of the subgenus Sauroleishmania as follows: L. (S) tarentolae, L.(S.) hemidactyli, L.(S.) ceramodactyli, L.(S.) nicollei, L.(S.) gymnodactyli, L.(S.) adleri, L.(S.) hoogstraali, L.(S.) senegalensis, L.(S.) gulikae, L.(S.) sp., L.(S.) sp. I, L.(S.) sp. II. 7 species and one form, L(S.) henrici, L.(S.) davidi, L.(S.) zmeevi, L.(S.) sofieffi, L.(S.) chameleonis, L.(S.) phrynocephali, L.(S.) helioscopi, L.(S.) sp. Markov e.a., 1964 must be excluded from the above subgenus since their description does not correspond to the development of the life cycle of Leishmania from reptiles. Flagellata Protozoa from the peripheral blood and intestine of reptiles, which were regarded by some authors as a "leptomonad stage of Leishmania", appear to belong to the genera Proteromonas, Monocercomonas and other Protozoa.

  20. Developmentally regulated sphingolipid degradation in Leishmania major.

    Directory of Open Access Journals (Sweden)

    Ou Zhang

    Full Text Available Leishmania parasites alternate between extracellular promastigotes in sandflies and intracellular amastigotes in mammals. These protozoans acquire sphingolipids (SLs through de novo synthesis (to produce inositol phosphorylceramide and salvage (to obtain sphingomyelin from the host. A single ISCL (Inositol phosphoSphingolipid phospholipase C-Like enzyme is responsible for the degradation of both inositol phosphorylceramide (the IPC hydrolase or IPCase activity and sphingomyelin (the SMase activity. Recent studies of a L. major ISCL-null mutant (iscl(- indicate that SL degradation is required for promastigote survival in stationary phase, especially under acidic pH. ISCL is also essential for L. major proliferation in mammals. To further understand the role of ISCL in Leishmania growth and virulence, we introduced a sole IPCase or a sole SMase into the iscl(- mutant. Results showed that restoration of IPCase only complemented the acid resistance defect in iscl(- promastigotes and improved their survival in macrophages, but failed to recover virulence in mice. In contrast, a sole SMase fully restored parasite infectivity in mice but was unable to reverse the promastigote defects in iscl(-. These findings suggest that SL degradation in Leishmania possesses separate roles in different stages: while the IPCase activity is important for promastigote survival and acid tolerance, the SMase activity is required for amastigote proliferation in mammals. Consistent with these findings, ISCL was preferentially expressed in stationary phase promastigotes and amastigotes. Together, our results indicate that SL degradation by Leishmania is critical for parasites to establish and sustain infection in the mammalian host.

  1. Comorbidity of Leishmania major with cutaneous sarcoidosis

    Directory of Open Access Journals (Sweden)

    Hamideh Moravvej

    2014-01-01

    Full Text Available Background: leishmaniasis infection might manifest as sarcoidosis; on the other hand, some evidences propose an association between sarcoidosis and leishmaniasis. Most of the times, it is impossible to discriminate idiopathic sarcoidosis from leishmaniasis by conventional histopathologic exam. Aim: We performed a cross-sectional study to examine the association of sarcoidosis with leishmaniasis in histopathologically diagnosed sarcoidal granuloma biopsy samples by polymerase chain reaction (PCR. Materials and Methods: We examined paraffin-embedded skin biopsy samples obtained from patients with clinical and histopathological diagnosis as naked sarcoidal granuloma, referred to Skin Research Center of Shaheed Beheshti Medical University from January 2001 to March 2010, in order to isolate Leishmania parasite. The samples were reassessed by an independent dermatopathologist. DNA extracted from all specimens was analyzed by the commercially available PCR kits (DNPTM Kit, CinnaGen, Tehran, Iran to detect endemic Leishmania species, namely leishmania major (L. major. Results: L. major was positive in PCR of Eight out of twenty-five examined samples. Conclusion: Cutaneous leishmaniasis may be misinterpreted as sarcoidosis; in endemic areas, when conventional methods fail to detect Leishmania parasite, PCR should be utilized in any granulomatous skin disease compatible with sarcoidosis, regardless of the clinical presentation or histopathological interpretation.

  2. The Leishmania infantum PUF proteins are targets of the humoral response during visceral leishmaniasis

    Directory of Open Access Journals (Sweden)

    Requena Jose M

    2010-01-01

    Full Text Available Abstract Background RNA-binding proteins of the PUF family share a conserved domain consisting of tandemly repeated 36-40 amino acid motifs (typically eight known as Puf repeats. Proteins containing tandem repeats are often dominant targets of humoral responses during infectious diseases. Thus, we considered of interest to analyze whether Leishmania PUF proteins result antigenic during visceral leishmaniasis (VL. Findings Here, employing whole-genome databases, we report the composition, and structural features, of the PUF family in Leishmania infantum. Additionally, the 10 genes of the L. infantum PUF family were cloned and used to express the Leishmania PUFs in bacteria as recombinant proteins. Finally, the antigenicity of these PUF proteins was evaluated by determining levels of specific antibodies in sera from experimentally infected hamsters. The Leishmania PUFs were all recognized by the sera, even though with different degree of reactivity and/or frequency of recognition. The reactivity of hamster sera against recombinant LiPUF1 and LiPUF2 was particularly prominent, and these proteins were subsequently assayed against sera from human patients. High antibody responses against rLiPUF1 and rLiPUF2 were found in sera from VL patients, but these proteins resulted also recognized by sera from Chagas' disease patients. Conclusion Our results suggest that Leishmania PUFs are targets of the humoral response during L. infantum infection and may represent candidates for serodiagnosis and/or vaccine reagents; however, it should be kept in mind the cross-reactivity of LiPUFs with antibodies induced against other trypanosomatids such as Trypanosoma cruzi.

  3. Dichotomy in the human CD4+ T-cell response to Leishmania parasites

    DEFF Research Database (Denmark)

    Kemp, M; Kurtzhals, J A; Kharazmi, A

    1994-01-01

    Leishmania parasites cause human diseases ranging from self-healing cutaneous ulcers to fatal systemic infections. In addition, many individuals become infected without developing disease. In mice the two subsets of CD4+ T cells, Th1 and Th2, have different effects on the outcome of experimental...... in humans, and that the balance between subsets of parasite-specific T cells may play an important regulatory role in determining the outcome of the infections....

  4. Transmission Potential of Antimony-Resistant Leishmania Field Isolates

    Science.gov (United States)

    Seblova, Veronika; Oury, Bruno; Eddaikra, Naouel; Aït-Oudhia, Khatima; Pratlong, Francine; Gazanion, Elodie; Maia, Carla; Volf, Petr

    2014-01-01

    We studied the development of antimony-resistant Leishmania infantum in natural vectors Lutzomyia longipalpis and Phlebotomus perniciosus to ascertain the risk of parasite transmission by sand flies. All three resistant strains produced fully mature late-stage infections in sand flies; moreover, the resistant phenotype was maintained after the passage through the vector. These results highlight the risk of circulation of resistant Leishmania strains and question the use of human drugs for treatment of dogs as Leishmania reservoirs. PMID:25049256

  5. Comparative proteomic analysis of antimony-resistant and -susceptible Leishmania braziliensis and Leishmania infantum chagasi lines.

    Science.gov (United States)

    Matrangolo, Fabiana S V; Liarte, Daniel B; Andrade, Laila C; de Melo, Melina F; Andrade, Juvana M; Ferreira, Rafael F; Santiago, André S; Pirovani, Carlos P; Silva-Pereira, Rosiane A; Murta, Silvane M F

    2013-08-01

    The emergence of drug-resistant Leishmania species is a significant problem in several countries. A comparative proteomic analysis of antimony-susceptible and antimony-resistant Leishmania braziliensis (LbSbR) and Leishmania infantum chagasi (LcSbR) lines was carried out using two-dimensional gel electrophoresis (2-DE) followed by mass spectrometry (LC/MS/MS) for protein identification. Out of 132 protein spots exclusive or up-regulated submitted to MS, we identified 80 proteins that corresponded to 57 distinct proteins. Comparative analysis of data showed that most of the protein spots with differential abundance in both species are involved in antioxidant defense, general stress response, glucose and amino acid metabolism, and cytoskeleton organization. Five proteins were commonly more abundant in both SbIII-resistant Leishmania lines: tryparedoxin peroxidase, alpha-tubulin, HSP70, HSP83, and HSP60. Analysis of the protein abundance by Western blotting assays confirmed our proteomic data. These assays revealed that cyclophilin-A is less expressed in both LbSbR and LcSbR lines. On the other hand, the expression of pteridine reductase is higher in the LbSbR line, whereas tryparedoxin peroxidase is overexpressed in both LbSbR and LcSbR lines. Together, these results show that the mechanism of antimony-resistance in Leishmania spp. is complex and multifactorial. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Comparative two-dimensional gel electrophoresis maps for promastigotes of Leishmania amazonensis and Leishmania major

    Directory of Open Access Journals (Sweden)

    Reynolds K. B. Brobey

    Full Text Available The outcome of Leishmania infections is determined by both the parasite species and the host genetic makeup. While much has been learned regarding immune responses to this parasite, our knowledge on parasite-derived factors is limited. The recent completion of the L. major and L. infantum genome sequence projects and concurrent advancement in proteomics technology would greatly accelerate the search for novel Leishmania proteins. Using a proteomics-based approach to study species-specific Leishmania proteins, we developed high-resolution, broad pH (3-10 two-dimensional gel electrophoresis (2-DE separations to determine protein-expression profiles between highly infectious forms of the parasitic species L. amazonensis (New World and L. major (Old World. Approximately 1,650 and 1,530 distinct protein spots were detected in the L. amazonensis and L. major gels, respectively. While a vast majority of the spots had similar distribution and intensity, a few were computationally defined as preferentially expressed in L. amazonensis in comparison to L. major, or vice versa. These data attest to the feasibility of establishing a 2-DE-based protein array for inter-species profiling of Leishmania proteins and provide the framework for future design of proteome studies of Leishmania.

  7. Identification of Leishmania chagasi from skin in Leishmania/HIV co-infection: a case report Identificação de Leishmania chagasi na pele em co-infecção Leishmania/HIV: relato de caso

    OpenAIRE

    Orsini Marcela; Silva Marcelo; Luz Zélia Maria Profeta da; Disch Jolandt; Fernandes Octávio; Moreira Dalton; Guedes Antonio Carlos Martins; Rabello Ana

    2002-01-01

    A case of HIV/Leishmania co-infection presenting both visceral and cutaneous manifestations is reported. Leishmania infection was confirmed by conventional methods (parasitological approach and serology) and by PCR. Leishmania chagasi isolated from the skin lesion was characterized by enzyme electrophoresis and by restriction fragment length polymorphism of the internal transcribed spacer of the ribosomal gene.É descrito um caso de co-infecção leishmania/HIV com manifestações cutâneas e visce...

  8. Further Evidence of an Association between the Presence of Leishmania RNA Virus 1 and the Mucosal Manifestations in Tegumentary Leishmaniasis Patients.

    Science.gov (United States)

    Cantanhêde, Lilian Motta; da Silva Júnior, Cipriano Ferreira; Ito, Marcos Massayuki; Felipin, Kátia Paula; Nicolete, Roberto; Salcedo, Juan Miguel Villalobos; Porrozzi, Renato; Cupolillo, Elisa; Ferreira, Ricardo de Godoi Mattos

    2015-01-01

    Tegumentary Leishmaniasis (TL) is endemic in Latin America, and Brazil contributes approximately 20 thousand cases per year. The pathogenesis of TL, however, is still not fully understood. Clinical manifestations vary from cutaneous leishmaniasis (CL) to more severe outcomes, such as disseminated leishmaniasis (DL), mucosal leishmaniasis (ML) and diffuse cutaneous leishmaniasis (DCL). Many factors have been associated with the severity of the disease and the development of lesions. Recent studies have reported that the presence of Leishmania RNA virus 1 infecting Leishmania (Leishmania RNA virus 1, LRV1) is an important factor associated with the severity of ML in experimental animal models. In the present study, 156 patients who attended Rondonia's Hospital of Tropical Medicine with both leishmaniasis clinical diagnoses (109 CL; 38 ML; 5 CL+ML; 3 DL and 1 DCL) and molecular diagnoses were investigated. The clinical diagnosis were confirmed by PCR by targeting hsp70 and kDNA DNA sequences and the species causing the infection were determined by HSP70 PCR-RFPL. The presence of LVR1 was tested by RT-PCR. Five Leishmania species were detected: 121 (77.6%) samples were positive for Leishmania (Viannia) braziliensis, 18 (11.5%) were positive for Leishmania (V.) guyanensis, 3 (1.8%) for Leishmania (V.) lainsoni, 2 (1.3%) for Leishmania (Leishmania) amazonensis and 2 (1.3%) for Leishmania (V.) shawi. Six (3.9%) samples were positive for Leishmania sp. but the species could not be determined, and 4 (2.6%) samples were suggestive of mixed infection by L. (V.) braziliensis and L. (V.) guyanensis. The virus was detected in L. braziliensis (N = 54), L. guyanensis (N = 5), L. amazonensis (N = 2), L. lainsoni (N = 1) and inconclusive samples (N = 6). Patients presenting with CL+ML, DL and DCL were excluded from further analysis. Association between the presence of the virus and the disease outcome were tested among the remaining 147 patients (CL = 109 and ML = 38). Of them, 71

  9. The role of mannose receptor during experimental leishmaniasis

    National Research Council Canada - National Science Library

    Oleg E. Akilov; Rachel E. Kasuboski; Cristina R. Carter; Mary Ann McDowell

    2007-01-01

    ...), specifically, recognizes mannose residues on the surface of Leishmania parasites. We studied the role of MR in the pathogenesis of experimental cutaneous and visceral leishmaniasis using MR-deficient [MR-knockout (KO)] C57BL/6 mice...

  10. Immunity to Leishmania and the rational search for vaccines against canine leishmaniasis.

    Science.gov (United States)

    Reis, Alexandre B; Giunchetti, Rodolfo C; Carrillo, Eugenia; Martins-Filho, Olindo A; Moreno, Javier

    2010-07-01

    The control of infection by Leishmania infantum (syn. Leishmania chagasi) in dogs is essential to stop the current spread of zoonotic visceral leishmaniasis. The past few years have seen significant advances in achieving efficient immunization of dogs and, more than ever before, an effective vaccine against canine leishmaniasis can now be considered a feasible goal. This article summarizes experimental data gathered from recent dog trials aimed at identifying immunological mechanisms implicated in protection against canine infection to discuss their potential to serve as quantitative surrogate markers of immunization and, more importantly, its usefulness to evaluate whether the immunity induced by the vaccine candidate is strong enough to protect against canine leishmaniasis. Copyright 2010 Elsevier Ltd. All rights reserved.

  11. Equine infection with Leishmania in Portugal

    Directory of Open Access Journals (Sweden)

    Rolão N.

    2005-06-01

    Full Text Available The present report describes the first case of equine leishmaniasis in Portugal. Leishmania infection was detected in one animal, which presented an ulcerated skin lesion. Diagnosis was based on serology by CIE, and parasite DNA detection by real-time PCR using a probe specific for L. infantum. This finding requests further leishmaniasis equine surveys in order to clarify the role of the horse as reservoir host in european endemic areas.

  12. Leishmania infantum and Leishmania braziliensis: differences and similarities to evade the innate immune system

    Directory of Open Access Journals (Sweden)

    Sarah Athayde Couto Falcão

    2016-08-01

    Full Text Available Visceral Leishmaniasis is a severe form of the disease, caused by Leishmania infantum in the New World. Patients present an anergic immune response that favors parasite establishment and spreading through tissues like bone marrow and liver. On the other hand, Leishmania braziliensis causes localized cutaneous lesions, which can be self healing in some individuals. Interactions between host and parasite are essential to understand disease pathogenesis and progression. In this context, dendritic cells (DCs act as essential bridges that connect innate and adaptive immune responses. In this way, the aim of this study was to compare the effects of these two Leishmania species, in some aspects of human dendritic cells biology to better understanding of the evasion mechanisms of Leishmania from host innate immune response. To do so, DCs were obtained from monocytes from whole peripheral blood’s healthy volunteers donors and infected with L. infantum or L. braziliensis for 24 hours. We observed similar rates of infection (around 40% as well as parasite burden for both Leishmania species. Concerning surface molecules, we observed that both parasites induced CD86 expression when DCs were infected for 24h. On the other hand, we detected a lower surface expression of CD209 in the presence of both L. braziliensis and L. infantum, but only the last one promoted the survival of dendritic cells after 24 hours. Therefore, DCs infected by both Leishmania species showed a higher expression of CD86 and a decrease of CD209 expression, suggesting that both enter DCs through CD209 molecule. However, only L. infantum had the ability to inhibit DC apoptotic death, as an evasion mechanism that enables its spreading to organs like bone marrow and liver. Lastly, L. braziliensis was more silent parasite, once it did not inhibit DC apoptosis in our in vitro model.

  13. The Leishmania metaphylome: a comprehensive survey of Leishmania protein phylogenetic relationships.

    Science.gov (United States)

    Valdivia, Hugo O; Scholte, Larissa L S; Oliveira, Guilherme; Gabaldón, Toni; Bartholomeu, Daniella C

    2015-10-30

    Leishmaniasis is a neglected parasitic disease with diverse clinical manifestations and a complex epidemiology. It has been shown that its parasite-related traits vary between species and that they modulate infectivity, pathogenicity, and virulence. However, understanding of the species-specific adaptations responsible for these features and their evolutionary background is limited. To improve our knowledge regarding the parasite biology and adaptation mechanisms of different Leishmania species, we conducted a proteome-wide phylogenomic analysis to gain insights into Leishmania evolution. The analysis of the reconstructed phylomes (totaling 45,918 phylogenies) allowed us to detect genes that are shared in pathogenic Leishmania species, such as calpain-like cysteine peptidases and 3'a2rel-related proteins, or genes that could be associated with visceral or cutaneous development. This analysis also established the phylogenetic relationship of several hypothetical proteins whose roles remain to be characterized. Our findings demonstrated that gene duplication constitutes an important evolutionary force in Leishmania, acting on protein families that mediate host-parasite interactions, such as amastins, GP63 metallopeptidases, cathepsin L-like proteases, and our methods permitted a deeper analysis of their phylogenetic relationships. Our results highlight the importance of proteome wide phylogenetic analyses to detect adaptation and evolutionary processes in different organisms and underscore the need to characterize the role of expanded and species-specific proteins in the context of Leishmania evolution by providing a framework for the phylogenetic relationships of Leishmania proteins. Phylogenomic data are publicly available for use through PhylomeDB (http://www.phylomedb.org).

  14. Infective stages of Leishmania in the sandfly vector and some observations on the mechanism of transmission Formas infectante de Leishmania no vetor flebotomíneo e algumas observações sobre o mecanismo de transmissão

    Directory of Open Access Journals (Sweden)

    Ralph Lainson

    1987-09-01

    Full Text Available Infective stages of Leishmania (Leishmania amazonensis, capable of producing amastigote infections in hamster skin, were shown to be present in the experimentally infected sandfly vector Lutzomyia flaviscutellata 15, 25, 40, 49, 70, 96 and 120 hours after the flies had received their infective blood-meal. Similarly, infective stages of Leishmania (L. chagasi were demonstrated in the experimentally infected vector Lu. longipalpis examined 38, 50, 63, 87, 110, 135, 171 and 221 hours following the infective blood-meal, by the intraperitoneal inoculation of the flagellates into hamsters. The question of whether or not transmission by the bite of the sandfly is dependent on the presence of [quot ]metacyclic[quot ] promastigotes in the mouthparts of the vector is discussed.Foi demonstrado através de infecção experimental, que estágios infectivos de Leishmania (L. amazonensis, capazes de produzir infecção na pele do hamster, encontram-se presentes no vetor flebotomíneo Lutzomyia flaviscutellata 15, 25, 40, 49, 70, 96 e 120 horas após o inseto ter recebido sua refeição sangüínea infectiva. Da mesma maneira, foi comprovada a presença de estágios infectivos de L. (L. chagasi em exemplares do vetor Lu. longipalpis, examinados 38, 50, 63, 87, 110, 135, 171 e 221 horas após o repasto sangüíneo infectivo - através da inoculação em hamster por via intraperitoneal dos flagelados obtidos desses fle botomíneos. A questão sobre a transmissão do gênero Leishmania pelo flebotomíneo ser ou não dependente da presença de promastigotos "metacíclios" na proboscis do vetor, é discutida.

  15. The transmission of Leishmania infantum chagasi by the bite of the Lutzomyia longipalpis to two different vertebrates

    Directory of Open Access Journals (Sweden)

    Secundino Nagila FC

    2012-01-01

    Full Text Available Abstract Background Sandflies are vectors of Leishmania, the causative agent of leishmaniasis in mammalian hosts, including humans. The protozoan parasite is transmitted by the sandfly bite during salivation that occurs at the moment of blood feeding. The components of vector saliva include anticlotting and vasodilatory factors that facilitate blood flow and immunomodulatory factors that inhibit wound healing and quell the immune response. Not surprisingly, these factors also play important roles in the establishment of Leishmania infection. To date, the majority of knowledge that has been generated regarding the process of Leishmania infection, including L. infantum chagasi transmission has been gathered by using intradermal or subcutaneous inoculation of purified parasites. Findings This study presents the establishment of a transmission model of Leishmania infantum chagasi by the bite of Lutzomyia longipalpis, the vector of American visceral leishmaniasis. The parasites were successfully transmitted by infected sandfly bites to mice and hamsters, indicating that both animals are good experimental models. The L. infantum chagasi dose that was transmitted in each single bite ranged from 10 to 10, 000 parasites, but 75% of the sandflies transmitted less than 300 parasites. Conclusions The strategy for initiating infection by sandfly bite of experimental animals facilitates future investigations into the complex and dynamic mechanisms of visceral leishmaniasis. It is important to elucidate the transmission mechanism of vector bites. This model represents a useful tool to study L. infantum chagasi infection transmitted by the vector.

  16. Leishmania major: Parasite Interactions Suggesting Sexuality

    Directory of Open Access Journals (Sweden)

    Sousa Maria Auxiliadora de

    1997-01-01

    Full Text Available In five experiments, Leishmania (Leishmania major (MRHO/SU/59/P-strain grew poorly when seeded in FYTS medium supplemented with 15% fetal calf serum, but presented several peculiar pairs of promastigotes diametrically opposed and attached at their posterior ends (5.8-13.5%. As seen in Giemsa-stained smears, a ring-like line and/or an enlargement, generally occurred at the parasite junction. A close proximity of nuclei, which sometimes were difficult to distinguish from each other, was also observed at this junction. Several of these pairs appeared to be composed of fused cells in which the nuclei could be apparently fused, as shown by fluorescence microscopy to detect ß-tubulin and DNA, and by scanning electron microscopy. Under other culture conditions these pairs were absent or occurred at very low rates (0.2-2.2%. Such pairs differ markedly from longitudinally dividing cells and resemble those described in two other Leishmania species, as well as in Herpetomonas megaseliae and Phytomonas davidi, suggesting steps of a putative sexual process

  17. Vaccination with the Leishmania infantum ribosomal proteins induces protection in BALB/c mice against Leishmania chagasi and Leishmania amazonensis challenge.

    Science.gov (United States)

    Chávez-Fumagalli, Miguel A; Costa, Mariana A F; Oliveira, Dulcilene M; Ramírez, Laura; Costa, Lourena E; Duarte, Mariana C; Martins, Vivian T; Oliveira, Jamil S; Olortegi, Carlos C; Bonay, Pedro; Alonso, Carlos; Tavares, Carlos A P; Soto, Manuel; Coelho, Eduardo A F

    2010-11-01

    Leishmania chagasi and Leishmania amazonensis are the etiologic agents of different clinical forms of human leishmaniasis in South America. In an attempt to select candidate antigens for a vaccine protecting against different Leishmania species, the efficacy of vaccination using Leishmania ribosomal proteins and saponin as adjuvant was examined in BALB/c mice against challenge infection with both parasite species. Mice vaccinated with parasite ribosomal proteins purified from Leishmania infantum plus saponin showed a specific production of IFN-γ, IL-12 and GM-CSF after in vitro stimulation with L. infantum ribosomal proteins. Vaccinated mice showed a reduction in the liver and spleen parasite burdens after L. chagasi infection. After L. amazonensis challenge, vaccinated mice showed a decrease of the dermal pathology and a reduction in the parasite loads in the footpad and spleen. In both models, protection was correlated to an IL-12-dependent production of IFN-γ by CD4(+) and CD8(+) T cells that activate macrophages for the synthesis of NO. In the protected mice a decrease in the parasite-mediated IL-4 and IL-10 responses was also observed. In mice challenged with L. amazonensis, lower levels of anti-parasite-specific antibodies were detected. Thus, Leishmania ribosomal proteins plus saponin fits the requirements to compose a pan-Leishmania vaccine. Copyright © 2010 Institut Pasteur. Published by Elsevier SAS. All rights reserved.

  18. First evidence of Leishmania infection in European brown hare (Lepus europaeus) in Greece: GIS analysis and phylogenetic position within the Leishmania spp.

    Science.gov (United States)

    Tsokana, C N; Sokos, C; Giannakopoulos, A; Mamuris, Z; Birtsas, P; Papaspyropoulos, K; Valiakos, G; Spyrou, V; Lefkaditis, M; Chatzopoulos, D C; Kantere, M; Manolakou, K; Touloudi, A; Burriel, A Rodi; Ferroglio, E; Hadjichristodoulou, C; Billinis, C

    2016-01-01

    Although the existence of a sylvatic transmission cycle of Leishmania spp., independent from the domestic cycle, has been proposed, data are scarce on Leishmania infection in wild mammals in Greece. In this study, we aimed to investigate the presence of Leishmania infection in the European brown hare in Greece, to infer the phylogenetic position of the Leishmania parasites detected in hares in Greece, and to identify any possible correlation between Leishmania infection in hares with environmental parameters, using the geographical information system (GIS). Spleen samples from 166 hares were tested by internal transcribed spacer-1 (ITS-1)-nested PCR for the detection of Leishmania DNA. Phylogenetic analysis was performed on Leishmania sequences from hares in Greece in conjunction with Leishmania sequences from dogs in Greece and 46 Leishmania sequences retrieved from GenBank. The Leishmania DNA prevalence in hares was found to be 23.49 % (95 % confidence interval (CI) 17.27-30.69). The phylogenetic analysis confirmed that the Leishmania sequences from hares in Greece belong in the Leishmania donovani complex. The widespread Leishmania infection in hares should be taken into consideration because under specific circumstances, this species can act as a reservoir host. This study suggests that the role of wild animals, including hares, in the epidemiology of Leishmania spp. in Greece deserves further elucidation.

  19. Glucosylated hydroxymethyluracil, DNA base J, prevents transcriptional readthrough in Leishmania

    NARCIS (Netherlands)

    van Luenen, Henri G. A. M.; Farris, Carol; Jan, Sabrina; Genest, Paul-Andre; Tripathi, Pankaj; Velds, Arno; Kerkhoven, Ron M.; Nieuwland, Marja; Haydock, Andrew; Ramasamy, Gowthaman; Vainio, Saara; Heidebrecht, Tatjana; Perrakis, Anastassis; Pagie, Ludo; van Steensel, Bas; Myler, Peter J.; Borst, Piet

    2012-01-01

    Some Ts in nuclear DNA of trypanosomes and Leishmania are hydroxylated and glucosylated to yield base J (β-D-glucosyl-hydroxymethyluracil). In Leishmania, about 99% of J is located in telomeric repeats. We show here that most of the remaining J is located at chromosome-internal RNA polymerase II

  20. Erythema exsudativum multiforme after a Leishmania skin test

    NARCIS (Netherlands)

    Wind, Bas S.; Guimarães, Luiz H.; Machado, Paulo R. L.

    2014-01-01

    A 45-year-old otherwise healthy male from an endemic region for Leishmania braziliensis infection in Bahia, Brazil, presented with three erosive hemorrhagic infiltrated plaques on the left shin accompanied with lymphadenopathy in the groin since one month. A Leishmania skin test performed on the

  1. Leishmania aethiopica: development of specific and sensitive PCR diagnostic test.

    Science.gov (United States)

    Kuru, Teklu; Janusz, Nick; Gadisa, Endalamaw; Gedamu, Lashitew; Aseffa, Abraham

    2011-08-01

    PCR has proved useful for rapid diagnosis and typing of Leishmania. Lack of specificity to discriminate between species and/or sensitivity to detect from clinical samples has always been an issue. Previously developed primers either require PCR-RFLP analysis for Leishmania aethiopica discrimination or lack sensitivity to detect L. aethiopica from clinical samples. Here we report the development and validation of L. aethiopica specific PCR primers (V5F/V10R) based on cysteine protease B (cpb), a multicopy and polymorphic gene of Leishmania. V5F/V10R primers differentiate L. aethiopica from Leishmania tropica, Leishmania major, Leishmania donovani and Leishmania infantum by direct PCR. In addition, they are sensitive enough to detect L. aethiopica from biopsy samples. The primers can be very useful for epidemiological studies, species typing and diagnosis of L. aethiopica directly from clinical samples. Implementation of these primers in routine L. aethiopica diagnosis can improve detection rate, save time, money and labor required for culturing Leishmania. Copyright © 2011 Elsevier Inc. All rights reserved.

  2. An overview on Leishmania vaccines: A narrative review article

    Science.gov (United States)

    Rezvan, Hossein; Moafi, Mohammad

    2015-01-01

    Leishmaniasis is one of the major health problems and categorized as a class I disease (emerging and uncontrolled) by World Health Organization (WHO), causing highly significant morbidity and mortality. Indeed, more than 350 million individuals are at risk of Leishmania infection, and about 1.6 million new cases occur causing more than 50 thousands death annually. Because of the severe toxicity and drug resistance, present chemotherapy regimen against diverse forms of Leishmania infections is not totally worthwhile. However, sound immunity due to natural infection, implies that vigor cellular immunity against Leishmania parasites, via their live, attenuated or killed forms, can be developed in dogs and humans. Moreover, genetically conserved antigens (in most of Leishmania species), and components of sand fly saliva confer potential immunogenic molecules for Leishmania vaccination. Vaccines successes in animal studies and some clinical trials clearly justify more researches and investments illuminating opportunities in suitable vaccine designation. PMID:25992245

  3. Natural infection of bats with Leishmania in Ethiopia.

    Science.gov (United States)

    Kassahun, Aysheshm; Sadlova, Jovana; Benda, Petr; Kostalova, Tatiana; Warburg, Alon; Hailu, Asrat; Baneth, Gad; Volf, Petr; Votypka, Jan

    2015-10-01

    The leishmaniases, a group of diseases with a worldwide-distribution, are caused by different species of Leishmania parasites. Both cutaneous and visceral leishmaniasis remain important public health problems in Ethiopia. Epidemiological cycles of these protozoans involve various sand fly (Diptera: Psychodidae) vectors and mammalian hosts, including humans. In recent years, Leishmania infections in bats have been reported in the New World countries endemic to leishmaniasis. The aim of this study was to survey natural Leishmania infection in bats collected from various regions of Ethiopia. Total DNA was isolated from spleens of 163 bats belonging to 23 species and 18 genera. Leishmania infection was detected by real-time (RT) PCR targeting a kinetoplast (k) DNA and internal transcribed spacer one (ITS1) gene of the parasite. Detection was confirmed by sequencing of the PCR products. Leishmania kDNA was detected in eight (4.9%) bats; four of them had been captured in the Aba-Roba and Awash-Methara regions that are endemic for leishmaniasis, while the other four specimens originated from non-endemic localities of Metu, Bedele and Masha. Leishmania isolates from two bats were confirmed by ITS1 PCR to be Leishmania tropica and Leishmania major, isolated from two individual bats, Cardioderma cor and Nycteris hispida, respectively. These results represent the first confirmed observation of natural infection of bats with the Old World Leishmania. Hence, bats should be considered putative hosts of Leishmania spp. affecting humans with a significant role in the transmission. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  4. [Importance of amastigote forms morphology to differentiate Leishmania infantum and Leishmania major species].

    Science.gov (United States)

    Aoun, K; Chahed, M K; Mokni, M; Harrat, Z; Bouratbine, A

    2003-01-01

    The microscopic study of the dermal smears of 62 cases of cutaneous leishmaniose, 27 infected by Leishmania (L.) infantum and 35 by L. major, showed that the amastigotes of L. infantum are meaningfully smaller (p < 0.001). This criteria is a simple pary alternative to distinguish these 2 species which have completely different epidemiology, recovery delay and prophylactic dispositions.

  5. The Genome Sequence of Leishmania (Leishmania) amazonensis: Functional Annotation and Extended Analysis of Gene Models

    Science.gov (United States)

    Real, Fernando; Vidal, Ramon Oliveira; Carazzolle, Marcelo Falsarella; Mondego, Jorge Maurício Costa; Costa, Gustavo Gilson Lacerda; Herai, Roberto Hirochi; Würtele, Martin; de Carvalho, Lucas Miguel; e Ferreira, Renata Carmona; Mortara, Renato Arruda; Barbiéri, Clara Lucia; Mieczkowski, Piotr; da Silveira, José Franco; Briones, Marcelo Ribeiro da Silva; Pereira, Gonçalo Amarante Guimarães; Bahia, Diana

    2013-01-01

    We present the sequencing and annotation of the Leishmania (Leishmania) amazonensis genome, an etiological agent of human cutaneous leishmaniasis in the Amazon region of Brazil. L. (L.) amazonensis shares features with Leishmania (L.) mexicana but also exhibits unique characteristics regarding geographical distribution and clinical manifestations of cutaneous lesions (e.g. borderline disseminated cutaneous leishmaniasis). Predicted genes were scored for orthologous gene families and conserved domains in comparison with other human pathogenic Leishmania spp. Carboxypeptidase, aminotransferase, and 3′-nucleotidase genes and ATPase, thioredoxin, and chaperone-related domains were represented more abundantly in L. (L.) amazonensis and L. (L.) mexicana species. Phylogenetic analysis revealed that these two species share groups of amastin surface proteins unique to the genus that could be related to specific features of disease outcomes and host cell interactions. Additionally, we describe a hypothetical hybrid interactome of potentially secreted L. (L.) amazonensis proteins and host proteins under the assumption that parasite factors mimic their mammalian counterparts. The model predicts an interaction between an L. (L.) amazonensis heat-shock protein and mammalian Toll-like receptor 9, which is implicated in important immune responses such as cytokine and nitric oxide production. The analysis presented here represents valuable information for future studies of leishmaniasis pathogenicity and treatment. PMID:23857904

  6. In vitro additive interaction between ketoconazole and antimony against intramacrophage Leishmania (Leishmania) amazonensis amastigotes.

    Science.gov (United States)

    Nunes, Débora Cristina de Oliveira; Bispo-da-Silva, Luiz Borges; Napolitano, Danielle Reis; Costa, Mônica Soares; Figueira, Márcia Moura Nunes Rocha; Rodrigues, Renata Santos; Rodrigues, Veridiana de Melo; Yoneyama, Kelly Aparecida Geraldo

    2017-01-01

    Leishmaniasis is a group of diseases caused by protozoa of Leishmania genus. The currently available treatments for this disease are expensive, present high toxicity and are associated to difficulties of healing and parasite resistance. Therefore, the development of strategies for leishmaniasis treatment is indispensable and includes reposition of existing drugs, as well as drug combination therapy. The aim of this study was to assess the nature of ketoconazole and antimony association on the cytotoxic effect against Leishmania (Leishmania) amazonensis amastigotes. The calculated mean sum of fractional 50% inhibitory concentration ([Formula: see text]ΣFIC50) was 2.54 and 1.43 for free and intracellular amastigotes, respectively, values that suggest an additive interaction between ketoconazole and antimony concerning to Leishmania toxicity only in the intramacrophage parasite form. Despite the clinical efficacy of ketoconazole-antimony combination has been shown in the literature, our study is the first to describe the nature of ketoconazole-antimony interaction against L. (L.) amazonensis amastigotes. Moreover, our results point out the need for future in vivo studies to confirm the nature of ketoconazole-antimony interaction and also to determine possible effective dosage regimens related to ketoconazole administration in association with the optimal lower dose of antimony.

  7. On Leishmania enriettii and Other Enigmatic Leishmania Species of the Neotropics

    Directory of Open Access Journals (Sweden)

    Ralph Lainson

    1997-05-01

    Full Text Available There are 20 named species of the genus Leishmania at present recognized in the New World, of which 14 are known to infect man. The present paper discusses the biological, biochemical and ecological features, where known, of six species which have not till now been found to cause human leishmaniasis; namely, Leishmania (Leishmania enriettii, L. (L. hertigi, L. (L. deanei, L. (L. aristidesi, L. (L. forattinii and L. (Viannia equatorensis. A protocol is suggested for attempts to discover the natural mammalian host(s and sandfly vector of L. (L. enriettii. Doubt is cast on the validity of the species L. herreri, described in Costa Rican sloths. Following the concensus of opinion that modern trypanosomatids derive from monogenetic intestinal flagellates of arthropods, phlebotomine sandflies are best regarded as the primary hosts of Leishmania species, with mammals acting as secondary hosts providing a source of parasites for these insects. There are probably natural barriers limiting the life-cycle of most leishmanial parasites to specific sandfly vectors

  8. Members of a large retroposon family are determinants of post-transcriptional gene expression in Leishmania.

    Directory of Open Access Journals (Sweden)

    Frédéric Bringaud

    2007-09-01

    Full Text Available Trypanosomatids are unicellular protists that include the human pathogens Leishmania spp. (leishmaniasis, Trypanosoma brucei (sleeping sickness, and Trypanosoma cruzi (Chagas disease. Analysis of their recently completed genomes confirmed the presence of non-long-terminal repeat retrotransposons, also called retroposons. Using the 79-bp signature sequence common to all trypanosomatid retroposons as bait, we identified in the Leishmania major genome two new large families of small elements--LmSIDER1 (785 copies and LmSIDER2 (1,073 copies--that fulfill all the characteristics of extinct trypanosomatid retroposons. LmSIDERs are approximately 70 times more abundant in L. major compared to T. brucei and are found almost exclusively within the 3'-untranslated regions (3'UTRs of L. major mRNAs. We provide experimental evidence that LmSIDER2 act as mRNA instability elements and that LmSIDER2-containing mRNAs are generally expressed at lower levels compared to the non-LmSIDER2 mRNAs. The considerable expansion of LmSIDERs within 3'UTRs in an organism lacking transcriptional control and their role in regulating mRNA stability indicate that Leishmania have probably recycled these short retroposons to globally modulate the expression of a number of genes. To our knowledge, this is the first example in eukaryotes of the domestication and expansion of a family of mobile elements that have evolved to fulfill a critical cellular function.

  9. Photodynamic vaccination of hamsters with inducible suicidal mutants of Leishmania amazonensis elicits immunity against visceral leishmaniasis.

    Science.gov (United States)

    Kumari, Shraddha; Samant, Mukesh; Khare, Prashant; Misra, Pragya; Dutta, Sujoy; Kolli, Bala Krishna; Sharma, Sharad; Chang, Kwang Poo; Dube, Anuradha

    2009-01-01

    Leishmania, naturally residing in the phagolysosomes of macrophages, is a suitable carrier for vaccine delivery. Genetic complementation of these trypanosomatid protozoa to partially rectify their defective heme-biosynthesis renders them inducible with delta-aminolevulinate to develop porphyria for selective photolysis, leaving infected host cells unscathed. Delivery of released "vaccines" to antigen-presenting cells is thus expected to enhance immune response, while their self-destruction presents added advantages of safety. Such suicidal L. amazonensis was found to confer immunoprophylaxis and immunotherapy on hamsters against L. donovani. Neither heat-killed nor live parasites without suicidal induction were effective. Photodynamic vaccination of hamsters with the suicidal mutants reduced the parasite loads by 99% and suppressed the development of disease. These suppressions were accompanied by an increase in Leishmania-specific delayed-type hypersensitivity and lymphoproliferation as well as in the levels of splenic iNOS, IFN-gamma, and IL-12 expressions and of Leishmania-specific IgG2 in the serum. Moreover, a single intravenous administration of T cells from vaccinated hamsters was shown to confer on naïve animals an effective cellular immunity against L. donovani challenges. The absence of lesion development at vaccination sites and parasites in the draining lymphnodes, spleen and liver further indicates that the suicidal mutants provide a safe platform for vaccine delivery against experimental visceral leishmaniasis.

  10. Photodynamic vaccination of hamsters with inducible suicidal mutants of Leishmania amazonensis elicits immunity against visceral leishmaniasis

    Science.gov (United States)

    Kumari, Shraddha; Samant, Mukesh; Khare, Prashant; Misra, Pragya; Dutta, Sujoy; Kolli, Bala Krishna; Sharma, Sharad; Chang, Kwang Poo; Dube, Anuradha

    2016-01-01

    Leishmania, naturally residing in the phagolysosomes of macrophages, is a suitable carrier for vaccine delivery. Genetic complementation of these trypanosomatid protozoa to partially rectify their defective heme-biosynthesis renders them inducible with δ-aminolevulinate to develop porphyria for selective photolysis, leaving infected host-cells unscathed. Delivery of released “vaccines” to antigen-presenting cells is thus expected to enhance immune response, while their self-destruction presents added advantages of safety. Such suicidal-L. amazonensis was found to confer immunoprophylaxis and immunotherapy on hamsters against L. donovani. Neither heat-killed nor live parasites without suicidal induction were effective. Photodynamic vaccination of hamsters with the suicidal-mutants reduced the parasite loads by 99% and suppressed the development of disease. These suppressions were accompanied by an increase in Leishmania-specific delayed-type hypersensitivity and lymphoproliferation as well as in the levels of splenic iNOS, IFN-γ and IL-12 expressions and of Leishmania-specific IgG2 in the serum. Moreover, a single intravenous administration of T-cells from vaccinated hamsters was shown to confer on naïve animals an effective cellular immunity against L. donovani challenges. The absence of lesion development at vaccination sites and parasites in the draining lymphnodes, spleen and liver further indicates that the suicidal mutants provide a safe platform for vaccine delivery against experimental visceral leishmaniasis. PMID:19053149

  11. Leishmania Infection: Laboratory Diagnosing in the Absence of a “Gold Standard”

    Science.gov (United States)

    Rodríguez-Cortés, Alhelí; Ojeda, Ana; Francino, Olga; López-Fuertes, Laura; Timón, Marcos; Alberola, Jordi

    2010-01-01

    There is no gold standard for diagnosing leishmaniases. Our aim was to assess the operative validity of tests used in detecting Leishmania infection using samples from experimental infections, a reliable equivalent to the classic definition of gold standard. Without statistical differences, the highest sensitivity was achieved by protein A (ProtA), immunoglobulin (Ig)G2, indirect fluorescenece antibody test (IFAT), lymphocyte proliferation assay, quantitative real-time polymerase chain reaction of bone marrow (qPCR-BM), qPCR-Blood, and IgG; and the highest specificity by IgG1, IgM, IgA, qPCR-Blood, IgG, IgG2, and qPCR-BM. Maximum positive predictive value was obtained simultaneously by IgG2, qPCR-Blood, and IgG; and maximum negative predictive value by qPCR-BM. Best positive and negative likelihood ratios were obtained by IgG2. The test having the greatest, statistically significant, area under the receiver operating characteristics curve was IgG2 enzyme-linked immunosorbent assay (ELISA). Thus, according to the gold standard used, IFAT and qPCR are far from fulfilling the requirements to be considered gold standards, and the test showing the highest potential to detect Leishmania infection is Leishmania-specific ELISA IgG2. PMID:20134001

  12. Molecular mechanisms of drug resistance in natural Leishmania populations vary with genetic background.

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    Saskia Decuypere

    Full Text Available The evolution of drug-resistance in pathogens is a major global health threat. Elucidating the molecular basis of pathogen drug-resistance has been the focus of many studies but rarely is it known whether a drug-resistance mechanism identified is universal for the studied pathogen; it has seldom been clarified whether drug-resistance mechanisms vary with the pathogen's genotype. Nevertheless this is of critical importance in gaining an understanding of the complexity of this global threat and in underpinning epidemiological surveillance of pathogen drug resistance in the field. This study aimed to assess the molecular and phenotypic heterogeneity that emerges in natural parasite populations under drug treatment pressure. We studied lines of the protozoan parasite Leishmania (L. donovani with differential susceptibility to antimonial drugs; the lines being derived from clinical isolates belonging to two distinct genetic populations that circulate in the leishmaniasis endemic region of Nepal. Parasite pathways known to be affected by antimonial drugs were characterised on five experimental levels in the lines of the two populations. Characterisation of DNA sequence, gene expression, protein expression and thiol levels revealed a number of molecular features that mark antimonial-resistant parasites in only one of the two populations studied. A final series of in vitro stress phenotyping experiments confirmed this heterogeneity amongst drug-resistant parasites from the two populations. These data provide evidence that the molecular changes associated with antimonial-resistance in natural Leishmania populations depend on the genetic background of the Leishmania population, which has resulted in a divergent set of resistance markers in the Leishmania populations. This heterogeneity of parasite adaptations provides severe challenges for the control of drug resistance in the field and the design of molecular surveillance tools for widespread

  13. Interleukin-12 augments a Th1-type immune response manifested as lymphocyte proliferation and interferon gamma production in Leishmania infantum-infected dogs.

    Science.gov (United States)

    Strauss-Ayali, Dalit; Baneth, Gad; Shor, Sharon; Okano, Fumiyoshi; Jaffe, Charles L

    2005-01-01

    The dog is the major reservoir for human visceral leishmaniasis caused by Leishmania infantum. Interleukin-12 is considered to have an essential role in the development of both innate and adaptive immunity to Leishmania spp. and other intracellular pathogens. This study focused on the influence of IL-12 in experimental and natural canine visceral leishmaniasis. Responses of peripheral blood mononuclear cells to IL-12, interleukin-10 and Leishmania soluble antigen were evaluated in L. infantum experimentally infected oligosymptomatic beagles, uninfected beagles, naturally infected polysymptomatic dogs, and their matched uninfected controls. Leishmania soluble antigen induced strong peripheral blood mononuclear cells proliferation both in experimentally infected dogs (median stimulation index [SI]=15.01), and in naturally infected dogs (SI=8.86), but not by cells from the control groups. IL-12 addition further enhanced cell proliferation in naturally (SI=14.95), but not in experimentally infected animals. Peripheral blood mononuclear cells from experimentally infected dogs were able to produce significant amounts of IFN-gamma (3.39 ng/ml) upon LSA stimulation, but no such production was detected in cells from naturally infected or control animals. Interestingly, addition of IL-12 reversed the inhibitory effect of LSA on IFN-gamma production by cells from polysymptomatic naturally infected dogs and the uninfected beagles (4.84 and 7.45 ng/ml, respectively), and further increased IFN-gamma production by peripheral blood mononuclear cells from experimentally infected oligosymptomatic dogs (29.28 ng/ml). IFN-gamma mRNA expression correlated well with IFN-gamma production. Addition of IL-10 to Leishmania soluble antigen stimulated peripheral blood mononuclear cells inhibited proliferation and IFN-gamma production in experimentally infected dogs. Thus, the ability of IL-12 to augment IFN-gamma production by peripheral blood mononuclear cells from dogs with experimental or

  14. DNA based vaccination with a cocktail of plasmids encoding immunodominant Leishmania (Leishmania) major antigens confers full protection in BALB/c mice.

    Science.gov (United States)

    Ahmed, Sami Ben Hadj; Touihri, Leila; Chtourou, Yessine; Dellagi, Koussay; Bahloul, Chokri

    2009-01-01

    Despite the lack of effective vaccines against parasitic diseases, the prospects of developing a vaccine against leishmaniasis are still high. With this objective, we have tested four DNA based candidate vaccines encoding to immunodominant leishmania antigens (LACKp24, TSA, LmSTI1 and CPa). These candidates have been previously reported as capable of eliciting at least partial protections in the BALB/c mice model of experimental cutaneous leishmaniasis. When tested under similar experimental conditions, all of them were able to induce similar partial protective effects, but none could induce a full protection. In order to improve the level of protection we have explored the approach of DNA based vaccination with different cocktails of plasmids encoding to the different immunodominant Leishmania antigens. A substantial increase of protection was achieved when the cocktail is composed of all of the four antigens; however, no full protection was achieved when mice were challenged with a high dose of parasite in their hind footpad. The full protection was only achieved after a challenge with a low parasitic dose in the dermis of the ear. It was difficult to determine clear protection correlates, other than the mixture of immunogens induced specific Th1 immune responses against each component. Therefore, such an association of antigens increased the number of targeted epitopes by the immune system with the prospects that the responses are at least additive if not synergistic. Even though, any extrapolation of this approach when applied to other animal or human models is rather hazardous, it undoubtedly increases the hopes of developing an effective leishmania vaccine.

  15. Detection and characterization of Leishmania (Leishmania and Leishmania (Viannia by SYBR green-based real-time PCR and high resolution melt analysis targeting kinetoplast minicircle DNA.

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    Marcello Ceccarelli

    Full Text Available Leishmaniasis is a neglected disease with a broad clinical spectrum which includes asymptomatic infection. A thorough diagnosis, able to distinguish and quantify Leishmania parasites in a clinical sample, constitutes a key step in choosing an appropriate therapy, making an accurate prognosis and performing epidemiological studies. Several molecular techniques have been shown to be effective in the diagnosis of leishmaniasis. In particular, a number of PCR methods have been developed on various target DNA sequences including kinetoplast minicircle constant regions. The first aim of this study was to develop a SYBR green-based qPCR assay for Leishmania (Leishmania infantum detection and quantification, using kinetoplast minicircle constant region as target. To this end, two assays were compared: the first used previously published primer pairs (qPCR1, whereas the second used a nested primer pairs generating a shorter PCR product (qPCR2. The second aim of this study was to evaluate the possibility to discriminate among subgenera Leishmania (Leishmania and Leishmania (Viannia using the qPCR2 assay followed by melting or High Resolution Melt (HRM analysis. Both assays used in this study showed good sensitivity and specificity, and a good correlation with standard IFAT methods in 62 canine clinical samples. However, the qPCR2 assay allowed to discriminate between Leishmania (Leishmania and Leishmania (Viannia subgenera through melting or HRM analysis. In addition to developing assays, we investigated the number and genetic variability of kinetoplast minicircles in the Leishmania (L. infantum WHO international reference strain (MHOM/TN/80/IPT1, highlighting the presence of minicircle subclasses and sequence heterogeneity. Specifically, the kinetoplast minicircle number per cell was estimated to be 26,566±1,192, while the subclass of minicircles amplifiable by qPCR2 was estimated to be 1,263±115. This heterogeneity, also observed in canine clinical

  16. Relationship between parasite load and immune responses in early stages of Leishmania donovani infection in inbred BALB/c mice.

    Science.gov (United States)

    Wahinya, D N; Mbati, P A; Jomo, P M; Githure, J I

    1998-03-01

    The aim of this study was to determine if a correlation exists between Leishmania donovani parasite load and the corresponding humoral and cellular mediated immune responses in the early stages of Leishmania donovani infection in inbred BALB/c mice. Five groups of ten BALB/c mice each were inoculated intraperitoneally with stationary phase metacyclic promastigotes of Leishmania donovani at doses 1 x 10(2), 1 x 10(4), 10(6) and 1 x 10(8) respectively per mouse. Group five mice were not manipulated in any way and were left to serve as control. At weekly intervals, for five weeks, the mice were assayed for cellular mediated immune responses to leishmania antigen by the delayed type hypersensitivity skin test (DTH) and humoral responses by the direct agglutination test (DAT) and the enzyme linked immunosorbent assay (ELISA). A correlation was established between parasite load and humoral responses as assayed by DAT and ELISA techniques. This study demonstrates that it is possible to diagnose visceral leishmaniasis in experimentally infected laboratory mice by DAT and ELISA. These techniques have the potential in screening large numbers of animals suspected to be reservoirs of visceral leishmaniasis by examining the peripheral blood taken from the tail of the animal.

  17. The Biting Midge Culicoides sonorensis (Diptera: Ceratopogonidae Is Capable of Developing Late Stage Infections of Leishmania enriettii.

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    Veronika Seblova

    Full Text Available Despite their importance in animal and human health, the epidemiology of species of the Leishmania enriettii complex remains poorly understood, including the identity of their biological vectors. Biting midges of the genus Forcipomyia (Lasiohelea have been implicated in the transmission of a member of the L. enriettii complex in Australia, but the far larger and more widespread genus Culicoides has not been investigated for the potential to include vectors to date.Females from colonies of the midges Culicoides nubeculosus Meigen and C. sonorensis Wirth & Jones and the sand fly Lutzomyia longipalpis Lutz & Nevia (Diptera: Psychodidae were experimentally infected with two different species of Leishmania, originating from Australia (Leishmania sp. AM-2004 and Brazil (Leishmania enriettii. In addition, the infectivity of L. enriettii infections generated in guinea pigs and golden hamsters for Lu. longipalpis and C. sonorensis was tested by xenodiagnosis. Development of L. enriettii in Lu. longipalpis was relatively poor compared to other Leishmania species in this permissive vector. Culicoides nubeculosus was not susceptible to infection by parasites from the L. enriettii complex. In contrast, C. sonorensis developed late stage infections with colonization of the thoracic midgut and the stomodeal valve. In hamsters, experimental infection with L. enriettii led only to mild symptoms, while in guinea pigs L. enriettii grew aggressively, producing large, ulcerated, tumour-like lesions. A high proportion of C. sonorensis (up to 80% feeding on the ears and nose of these guinea pigs became infected.We demonstrate that L. enriettii can develop late stage infections in the biting midge Culicoides sonorensis. This midge was found to be susceptible to L. enriettii to a similar degree as Lutzomyia longipalpis, the vector of Leishmania infantum in South America. Our results support the hypothesis that some biting midges could be natural vectors of the L

  18. Histopatologia da forma localizada de leishmaniose cutânea por Leishmania (Leishmania amazonensis Histopathology of the localized form of cutaneous leishmaniasis due to Leishmania (Leishmania amazonensis

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    Mário A. P. Moraes

    1994-10-01

    Full Text Available São descritas as alterações microscópicas presentes na forma localizada (ulcerada da Leishmaniose cutânea produzida por Leishmania (Leishmania amazonensis. Nesse tipo de manifestação, menos conhecido do que a forma anérgica ou difusa devida ao mesmo agente, as lesões são clinicamente idênticas às de leishmaniose cutânea causada por espécies outras de Leishmania, pertencentes ao subgênero Viannia. Na infecção localizada por L. (L. amazonensis, entretanto, há um aspecto peculiar, só recentemente conhecido, ou seja, cerca de 50% dos indivíduos atingidos não reagem ao teste de Montenegro. A principal característica histológica observada foi a acumulação na derme, quase sempre focal, de numerosos macrófagos contendo no citoplasma um grande vacúolo cheio de amastigotas. O quadro é semelhante ao da forma difusa, porém sem o aspecto histiocitomatóide, próprio da última. Afora esses grupos de macrófagos, vêem-se também, na forma localizada, muitas células mononucleares da inflamação, principalmente plasmócitos e macrófagos não parasitados. Os acúmulos de macrófagos com amastigotas, quando volumosos, podem sofrer necrose na parte central; os parasitos, contidos nas células, são destruídos com elas ou liberados, e sua eliminação através da úlcera deve contribuir para a cura do processo. Esse tipo de necrose nunca foi descrito em casos da forma difusa. Não houve grande diferença, no quadro histológico, entre pacientes Montenegro-negativos e positivos. Apenas em alguns casos, do grupo Montenegro-positivo, havia granulomas formados por histiócitos epitelióides sem parasitos. Quanto à persistência das células com parasitos nas lesões, observou-se que aos seis meses ou mais de evolução, em ambos os grupos, ainda estavam elas presentes. Tal achado não é comum na leishmaniose tegumentar por L. (V. braziliensis.The microscopic changes found in the localized form of the human cutaneous leishmaniasis due

  19. Distinct Macrophage Fates after in vitro Infection with Different Species of Leishmania: Induction of Apoptosis by Leishmania (Leishmania) amazonensis, but Not by Leishmania (Viannia) guyanensis.

    Science.gov (United States)

    DaMata, Jarina Pena; Mendes, Bárbara Pinheiro; Maciel-Lima, Kátia; Menezes, Cristiane Alves Silva; Dutra, Walderez Ornelas; Sousa, Lirlândia Pires; Horta, Maria Fátima

    2015-01-01

    Leishmania is an intracellular parasite in vertebrate hosts, including man. During infection, amastigotes replicate inside macrophages and are transmitted to healthy cells, leading to amplification of the infection. Although transfer of amastigotes from infected to healthy cells is a crucial step that may shape the outcome of the infection, it is not fully understood. Here we compare L. amazonensis and L. guyanensis infection in C57BL/6 and BALB/c mice and investigate the fate of macrophages when infected with these species of Leishmania in vitro. As previously shown, infection of mice results in distinct outcomes: L. amazonensis causes a chronic infection in both strains of mice (although milder in C57BL/6), whereas L. guyanensis does not cause them disease. In vitro, infection is persistent in L. amazonensis-infected macrophages whereas L. guyanensis growth is controlled by host cells from both strains of mice. We demonstrate that, in vitro, L. amazonensis induces apoptosis of both C57BL/6 and BALB/c macrophages, characterized by PS exposure, DNA cleavage into nucleosomal size fragments, and consequent hypodiploidy. None of these signs were seen in macrophages infected with L. guyanensis, which seem to die through necrosis, as indicated by increased PI-, but not Annexin V-, positive cells. L. amazonensis-induced macrophage apoptosis was associated to activation of caspases-3, -8 and -9 in both strains of mice. Considering these two species of Leishmania and strains of mice, macrophage apoptosis, induced at the initial moments of infection, correlates with chronic infection, regardless of its severity. We present evidence suggestive that macrophages phagocytize L. amazonensis-infected cells, which has not been verified so far. The ingestion of apoptotic infected macrophages by healthy macrophages could be a way of amastigote spreading, leading to the establishment of infection.

  20. Distinct Macrophage Fates after in vitro Infection with Different Species of Leishmania: Induction of Apoptosis by Leishmania (Leishmania amazonensis, but Not by Leishmania (Viannia guyanensis.

    Directory of Open Access Journals (Sweden)

    Jarina Pena DaMata

    Full Text Available Leishmania is an intracellular parasite in vertebrate hosts, including man. During infection, amastigotes replicate inside macrophages and are transmitted to healthy cells, leading to amplification of the infection. Although transfer of amastigotes from infected to healthy cells is a crucial step that may shape the outcome of the infection, it is not fully understood. Here we compare L. amazonensis and L. guyanensis infection in C57BL/6 and BALB/c mice and investigate the fate of macrophages when infected with these species of Leishmania in vitro. As previously shown, infection of mice results in distinct outcomes: L. amazonensis causes a chronic infection in both strains of mice (although milder in C57BL/6, whereas L. guyanensis does not cause them disease. In vitro, infection is persistent in L. amazonensis-infected macrophages whereas L. guyanensis growth is controlled by host cells from both strains of mice. We demonstrate that, in vitro, L. amazonensis induces apoptosis of both C57BL/6 and BALB/c macrophages, characterized by PS exposure, DNA cleavage into nucleosomal size fragments, and consequent hypodiploidy. None of these signs were seen in macrophages infected with L. guyanensis, which seem to die through necrosis, as indicated by increased PI-, but not Annexin V-, positive cells. L. amazonensis-induced macrophage apoptosis was associated to activation of caspases-3, -8 and -9 in both strains of mice. Considering these two species of Leishmania and strains of mice, macrophage apoptosis, induced at the initial moments of infection, correlates with chronic infection, regardless of its severity. We present evidence suggestive that macrophages phagocytize L. amazonensis-infected cells, which has not been verified so far. The ingestion of apoptotic infected macrophages by healthy macrophages could be a way of amastigote spreading, leading to the establishment of infection.

  1. Arginase activity of Leishmania isolated from patients with cutaneous leishmaniasis.

    Science.gov (United States)

    Badirzadeh, A; Taheri, T; Abedi-Astaneh, F; Taslimi, Y; Abdossamadi, Z; Montakhab-Yeganeh, H; Aghashahi, M; Niyyati, M; Rafati, S

    2017-09-01

    Cutaneous leishmaniasis (CL) is one of the most important vector-borne parasitic diseases, highly endemic in Iran, and its prevalence is increasing all over the country. Arginase (ARG) activity in isolated Leishmania parasites from CL patients is yet to be explored. This study aimed to compare the ARG activity of isolated Leishmania promastigotes from CL patients with a standard strain of Leishmania major and its influences on the disease pathogenesis. We recruited 16 confirmed CL patients from Qom Province, in central Iran; after detection of Leishmania species using PCR-RFLP, we assessed the levels of ARG in the isolated promastigotes and determined the parasites' growth rate. Only L. major was identified from CL patients. The level of ARG activity in the isolated Leishmania promastigotes from CL patients was significantly higher than that obtained from the standard strain of L. major. No significant correlations between ARG activity and lesion size, number or duration were observed; in contrast, a significant negative correlation was seen between ARG level and Leishmania' growth rate. The obtained results suggest that increased ARG expression and activity in the isolated Leishmania promastigotes might contribute to the higher parasite infectivity and play a major role in the pathogenicity of the CL. © 2017 John Wiley & Sons Ltd.

  2. Recognition of Leishmania antigens by T lymphocytes from nonexposed individuals

    DEFF Research Database (Denmark)

    Kemp, M; Hansen, M B; Theander, T G

    1992-01-01

    Crude antigen preparations of Leishmania promastigote sonicates were found to induce in vitro proliferation and gamma interferon production in peripheral blood mononuclear cells (PBMC) from individuals without known exposure to the parasite. The proliferating cells were mainly CD2-positive T cells...... was observed. Cell populations depleted of either CD45R0-positive cells or CD45RA-positive cells both responded to PHA. We conclude that presumably unexposed individuals have a low number of Leishmania-reactive T cells in their circulatory systems. The Leishmania-reactive T cells in these individuals are most...

  3. Exploring the Association of Surface Plasmon Resonance with Recombinant MHC:Ig Hybrid Protein as a Tool for Detecting T Lymphocytes in Mice Infected with Leishmania (Leishmania amazonensis

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    Lenilton Silva da Silveira-Júnior

    2017-01-01

    Full Text Available A surface plasmon resonance- (SPR- based recognition method applying H-2 Ld:Ig/peptides complexes for ex vivo monitoring cellular immune responses during murine infection with Leishmania (Leishmania amazonensis is described. Lymphocytes from lesion-draining popliteal lymph nodes were captured on a carboxylated sensor chip surface previously functionalized with H-2 Ld:Ig (DimerX protein bound to synthetic peptides derived from the COOH-terminal region of cysteine proteinase B of L. (L. amazonensis. In computational analysis, these peptides presented values of kinetic constants favorable to form complexes with H-2 Ld at neutral pH, with a Gibbs free energy ΔG°<0. The assayed DimerX:peptide complexes presented the property of attaching to distinct T lymphocytes subsets, obtained from experimentally infected BALB/c mice, in each week of infection, thus indicating a temporal variation in specific T lymphocytes populations, each directed to a different COOH-terminal region-derived peptide. The experimental design proposed herein is an innovative approach for cellular immunology studies of a neglected disease, providing a useful tool for the analysis of specific T lymphocytes subsets.

  4. Congenital Transmission of Experimental Leishmaniasis in a Hamster Model

    OpenAIRE

    Osorio, Yaneth; Rodriguez, Luz D.; Diana L Bonilla; Peniche, Alex G.; Henao, Hector; Saldarriaga, Omar; Bruno L. Travi

    2012-01-01

    Little information is available on transplacental transmission of Leishmania spp. We determined the frequency and impact of congenital infection caused by Leishmania panamensis or L. donovani in experimentally infected hamsters. A polymerase chain reaction showed that congenital transmission occurred in 25.8% (24 of 93) of offspring born to L. panamensis-infected hamsters and 14.6% (11 of 75) offspring born to L. donovani-infected hamsters. Mortality during lactation was higher in offspring b...

  5. Effects of Brazilian propolis on Leishmania amazonensis

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    Diana Copi Ayres

    2007-03-01

    Full Text Available Leishmaniasis, an endemic parasitosis that leads to chronic cutaneous, mucocutaneous or visceral lesions, is part of those diseases, which still requires improved control tools. Propolis has shown activities against different bacteria, fungi, and parasites. In this study we investigated the effect of four ethanolic extracts of typified propolis collected in different Brazilian states, on Leishmania amazonensis performing assays with promastigote forms, extracellular amastigotes, and on infected peritoneal macrophages. Ethanolic extracts of all propolis samples (BRG, BRPG, BRP-1, and BRV were capable to reduce parasite load as monitored by the percentage of infected macrophages and the number of intracellular parasites. BRV sample called red propolis, collected in the state of Alagoas, and containing high concentration of prenylated and benzophenones compounds, was the most active extract against L. amazonensis. The anti-Leishmania effect of BRV sample was increased in a concentration and time dependent manner. BRV treatment proved to be non-toxic to macrophage cultures. Since BRV extract at the concentration of 25 µg/ml reduced the parasite load of macrophages while presented no direct toxic to promastigotes and extracellular amastigotes, it was suggested that constituents of propolis intensify the mechanism of macrophage activation leading to killing of L. amazonensis. Our results demonstrate, for the first time, that ethanolic extracts of Brazilian propolis reduce L. amazonensis infection in macrophages, and encourage further studies of this natural compound in animal models of leishmaniasis.

  6. Cyclic nucleotide specific phosphodiesterases of Leishmania major

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    Linder Markus

    2006-03-01

    Full Text Available Abstract Background Leishmania represent a complex of important human pathogens that belong to the systematic order of the kinetoplastida. They are transmitted between their human and mammalian hosts by different bloodsucking sandfly vectors. In their hosts, the Leishmania undergo several differentiation steps, and their coordination and optimization crucially depend on numerous interactions between the parasites and the physiological environment presented by the fly and human hosts. Little is still known about the signalling networks involved in these functions. In an attempt to better understand the role of cyclic nucleotide signalling in Leishmania differentiation and host-parasite interaction, we here present an initial study on the cyclic nucleotide-specific phosphodiesterases of Leishmania major. Results This paper presents the identification of three class I cyclic-nucleotide-specific phosphodiesterases (PDEs from L. major, PDEs whose catalytic domains exhibit considerable sequence conservation with, among other, all eleven human PDE families. In contrast to other protozoa such as Dictyostelium, or fungi such as Saccharomyces cerevisiae, Candida ssp or Neurospora, no genes for class II PDEs were found in the Leishmania genomes. LmjPDEA contains a class I catalytic domain at the C-terminus of the polypeptide, with no other discernible functional domains elsewhere. LmjPDEB1 and LmjPDEB2 are coded for by closely related, tandemly linked genes on chromosome 15. Both PDEs contain two GAF domains in their N-terminal region, and their almost identical catalytic domains are located at the C-terminus of the polypeptide. LmjPDEA, LmjPDEB1 and LmjPDEB2 were further characterized by functional complementation in a PDE-deficient S. cerevisiae strain. All three enzymes conferred complementation, demonstrating that all three can hydrolyze cAMP. Recombinant LmjPDEB1 and LmjPDEB2 were shown to be cAMP-specific, with Km values in the low micromolar range

  7. Evaluation of recombinant Leishmania polyprotein plus glucopyranosyl lipid A stable emulsion vaccines against sand fly-transmitted Leishmania major in C57BL/6 mice.

    Science.gov (United States)

    Peters, Nathan C; Bertholet, Sylvie; Lawyer, Phillip G; Charmoy, Melanie; Romano, Audrey; Ribeiro-Gomes, Flavia L; Stamper, Lisa W; Sacks, David L

    2012-11-15

    Numerous experimental Leishmania vaccines have been developed to prevent the visceral and cutaneous forms of Leishmaniasis, which occur after exposure to the bite of an infected sand fly, yet only one is under evaluation in humans. KSAC and L110f, recombinant Leishmania polyproteins delivered in a stable emulsion (SE) with the TLR4 agonists monophosphoryl lipid A or glucopyranosyl lipid A (GLA) have shown protection in animal models. KSAC+GLA-SE protected against cutaneous disease following sand fly transmission of Leishmania major in susceptible BALB/c mice. Similar polyprotein adjuvant combinations are the vaccine candidates most likely to see clinical evaluation. We assessed immunity generated by KSAC or L110f vaccination with GLA-SE following challenge with L. major by needle or infected sand fly bite in resistant C57BL/6 mice. Polyprotein-vaccinated mice had a 60-fold increase in CD4(+)IFN-γ(+) T cell numbers versus control animals at 2 wk post-needle inoculation of L. major, and this correlated with a 100-fold reduction in parasite load. Immunity did not, however, reach levels observed in mice with a healed primary infection. Following challenge by infected sand fly bite, polyprotein-vaccinated animals had comparable parasite loads, greater numbers of neutrophils at the challenge site, and reduced CD4(+)IFN-γ(+)/IL-17(+) ratios versus nonvaccinated controls. In contrast, healed animals had significantly reduced parasite loads and higher CD4(+)IFN-γ(+)/IL-17(+) ratios. These observations demonstrate that vaccine-induced protection against needle challenge does not necessarily translate to protection following challenge by infected sand fly bite.

  8. An epidemic outbreak of canine cutaneous leishmaniasis in Colombia caused by Leishmania braziliensis and Leishmania panamensis.

    Science.gov (United States)

    Vélez, Iván D; Carrillo, Lina M; López, Liliana; Rodríguez, Erwin; Robledo, Sara M

    2012-05-01

    The largest recorded outbreak of cutaneous leishmaniasis in Colombia's history occurred during 2005-2009 in soldiers of the Colombian Army, with ~40,000 cases. This outbreak was caused by the influx of military personnel into the jungle with the mission of combat illicit crops and the guerrilla. The soldiers remain for long periods within the rainforest and are exposed to the bite of infected sand flies. During the military activities, soldiers work with dogs specially trained to detect landmines, and therefore, dogs are also exposed to the infected sand flies and show high incidence of cutaneous leishmaniasis (CL). This work describes an epidemic outbreak of canine CL caused by Leishmania braziliensis and Leishmania panamensis in Colombia, South America. The clinical features of the disease and the response to treatment with pentavalent antimonials observed in 72 guard dogs from the Colombian Army are described. A program for prevention and control of canine CL is also discussed.

  9. Antiproliferative and ultrastructural effects of phenethylamine derivatives on promastigotes and amastigotes of Leishmania (Leishmania) infantum chagasi.

    Science.gov (United States)

    Brasil, Paula Ferreira; de Freitas, Júlia Araújo; Barreto, Anna Léa Silva; Adade, Camila Marques; Reis de Sá, Leandro Figueira; Constantino-Teles, Pamella; Toledo, Fabiano Travanca; de Sousa, Bruno A; Gonçalves, Augusto Cesar; Romanos, Maria Teresa Villela; Comasseto, João V; Dos Santos, Alcindo A; Tessis, Ana Claudia; Souto-Padrón, Thais; Soares, Rosangela Maria A; Ferreira-Pereira, Antonio

    2017-04-01

    Leishmania (Leishmania) infantum chagasi is one of the agents that cause visceral leishmaniasis. This disease occurs more frequently in third world countries, such as Brazil. The treatment is arduous, and is dependent on just a few drugs like the antimonial derivatives and amphotericin B. Moreover, these drugs are not only expensive, but they can also cause severe side effects and require long-term treatment. Therefore, it is very important to find new compounds that are effective against leishmaniasis. In the present work we evaluated a new group of synthetic amides against the promastigote and amastigote forms of L. infantum chagasi. The results showed that one of these amides in particular, presented very effective activity against the promastigotes and amastigotes of L. infantum chagasi at low concentrations and it also presented low toxicity for mammal cells, which makes this synthetic amide a promising drug for combating leishmaniasis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. Mucosal Leishmaniasis caused by Leishmania (Viannia braziliensis and Leishmania (Viannia guyanensis in the Brazilian Amazon.

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    Jorge Augusto de Oliveira Guerra

    Full Text Available BACKGROUND: Leishmania (Viannia braziliensis is a parasite recognized as the most important etiologic agent of mucosal leishmaniasis (ML in the New World. In Amazonia, seven different species of Leishmania, etiologic agents of human Cutaneous Leishmaniasis, have been described. Isolated cases of ML have been described for several different species of Leishmania: L. (V. panamensis, L. (V. guyanensis and L. (L. amazonensis. METHODOLOGY: Leishmania species were characterized by polymerase chain reaction (PCR of tissues taken from mucosal biopsies of Amazonian patients who were diagnosed with ML and treated at the Tropical Medicine Foundation of Amazonas (FMTAM in Manaus, Amazonas state, Brazil. Samples were obtained retrospectively from the pathology laboratory and prospectively from patients attending the aforementioned tertiary care unit. RESULTS: This study reports 46 cases of ML along with their geographical origin, 30 cases caused by L. (V. braziliensis and 16 cases by L. (V. guyanensis. This is the first record of ML cases in 16 different municipalities in the state of Amazonas and of simultaneous detection of both species in 4 municipalities of this state. It is also the first record of ML caused by L. (V. guyanensis in the states of Pará, Acre, and Rondônia and cases of ML caused by L. (V. braziliensis in the state of Rondônia. CONCLUSIONS/SIGNIFICANCE: L. (V. braziliensis is the predominant species that causes ML in the Amazon region. However, contrary to previous studies, L. (V. guyanensis is also a significant causative agent of ML within the region. The clinical and epidemiological expression of ML in the Manaus region is similar to the rest of the country, although the majority of ML cases are found south of the Amazon River.

  11. Implications of a Neotropical Origin of the Genus Leishmania

    Directory of Open Access Journals (Sweden)

    Noyes Harry

    1998-01-01

    Full Text Available The hypothesis of a Neotropical origin of the Leishmania/Endotrypanum clade is reviewed. The position of the L. (Sauroleishmania external to the subgenus L. (Leishmania is not consistent with the Neotropical origin of the latter subgenus. It is suggested that this may be a consequence of a faster evolutionary rate in the L. (Sauroleishmania. The implications for the classsification of the phlebotomine sandflies of the hypothesis for a Neotropical origin of the Leishmania is also considered. The classification of Galati (1995 is proposed to be most consistent with the hypothesis of a Neotropical origin of the Leishmania, whilst classifications which place the New and Old World species in separate taxa are inconsistent with this hypothesis.

  12. Estimation of the minimum number of leishmania major amastigotes ...

    African Journals Online (AJOL)

    Estimation of the minimum number of leishmania major amastigotes required for infecting phlebotomus duboscqi (Diptera: psychodidae). C Anjili, B Langat, R Lugalia, P Mwanyumba, P Ngumbi, PA Mbati, J Githure, WK Tonui ...

  13. Novel Leishmania and Malaria Potassium Channels: Candidate Therapeutic Targets

    National Research Council Canada - National Science Library

    McDonald, Thomas V

    2005-01-01

    .... major and T. cruzi). Using a combination of cultured mammalian cells and Xenopus oocytes for heterologous expression we have evidence that 2 channels from malaria [PFK1 & PFK22] and Leishmania [LMK1 & LMK2] generate K+...

  14. Cutaneous leishmaniasis with lymphadenopathy due to Leishmania donovani

    NARCIS (Netherlands)

    Faber, W. R.; Wonders, J.; Jensema, A. J.; Chocholova, E.; Kager, P. A.

    2009-01-01

    Summary We describe a case of cutaneous leishmaniasis with lymphadenopathy due to Leishmania donovani, which was successfully treated with oral miltefosine. Given the increased prevalence of travelling, patients presenting with lymph-node enlargement should have leishmaniasis included in the

  15. TROMBOCITOPENIA IMMUNOMEDIATA SECONDARIA IN CANI NATURALMENTE INFETTI DA LEISHMANIA INFANTUM

    OpenAIRE

    Prisco, Michele

    2009-01-01

    Lo studio si prefigge di indagare, mediante immunofluorescenza indiretta e citometria a flusso, se la presenza di anticorpi anti-piastrine può essere associata all’occorrenza di trombocitopenia immunomediata in cani naturalmente infetti da Leishmania infantum.

  16. Leishmania RNA virus controls the severity of mucocutaneous leishmaniasis.

    Science.gov (United States)

    Ives, Annette; Ronet, Catherine; Prevel, Florence; Ruzzante, Giulia; Fuertes-Marraco, Silvia; Schutz, Frederic; Zangger, Haroun; Revaz-Breton, Melanie; Lye, Lon-Fye; Hickerson, Suzanne M; Beverley, Stephen M; Acha-Orbea, Hans; Launois, Pascal; Fasel, Nicolas; Masina, Slavica

    2011-02-11

    Mucocutaneous leishmaniasis is caused by infections with intracellular parasites of the Leishmania Viannia subgenus, including Leishmania guyanensis. The pathology develops after parasite dissemination to nasopharyngeal tissues, where destructive metastatic lesions form with chronic inflammation. Currently, the mechanisms involved in lesion development are poorly understood. Here we show that metastasizing parasites have a high Leishmania RNA virus-1 (LRV1) burden that is recognized by the host Toll-like receptor 3 (TLR3) to induce proinflammatory cytokines and chemokines. Paradoxically, these TLR3-mediated immune responses rendered mice more susceptible to infection, and the animals developed an increased footpad swelling and parasitemia. Thus, LRV1 in the metastasizing parasites subverted the host immune response to Leishmania and promoted parasite persistence.

  17. A comparison of molecular markers to detect Lutzomyia longipalpis naturally infected with Leishmania (Leishmania infantum

    Directory of Open Access Journals (Sweden)

    Kárita Cláudia Freitas-Lidani

    2014-07-01

    Full Text Available The aim of the present study was to detect natural infection by Leishmania (Leishmania infantum in Lutzomyia longipalpis captured in Barcarena, state of Pará, Brazil, through the use of three primer sets. With this approach, it is unnecessary to previously dissect the sandfly specimens. DNA of 280 Lu. longipalpis female specimens were extracted from the whole insects. PCR primers for kinetoplast minicircle DNA (kDNA, the mini-exon gene and the small subunit ribosomal RNA (SSU-rRNA gene of Leishmania were used, generating fragments of 400 bp, 780 bp and 603 bp, respectively. Infection by the parasite was found with the kDNA primer in 8.6% of the cases, with the mini-exon gene primer in 7.1% of the cases and with the SSU-rRNA gene primer in 5.3% of the cases. These data show the importance of polymerase chain reaction as a tool for investigating the molecular epidemiology of visceral leishmaniasis by estimating the risk of disease transmission in endemic areas, with the kDNA primer representing the most reliable marker for the parasite.

  18. Natural canine infection by Leishmania infantum and Leishmania amazonensis and their implications for disease control

    Directory of Open Access Journals (Sweden)

    Letícia da Cruz Sanches

    Full Text Available Abstract Leishmaniasis is a major public health problem worldwide. Because Leishmania can adapt to new hosts or vectors, knowledge concerning the current etiological agent in dogs is important in endemic areas. This study aimed to identify the Leishmania species detected in 103 samples of peripheral blood from dogs that were naturally infected with these protozoa. The diagnosis of leishmaniasis was determined through parasitological examination, the indirect enzyme-linked immunosorbent assay (ELISA and the polymerase chain reaction (PCR. The Leishmania species were identified by means of PCR-restriction fragment length polymorphism (PCR-RFLP. The samples were subjected to PCR using oligonucleotide primers that amplify the intergenic region ITS1 of the rRNA gene in order to identify the species. The amplified DNA was digested using the restriction enzyme HaeIII. A restriction profile identical to L. amazonensis was shown in 77/103 samples and the profile was similar to L. infantum in 17/103. However, a mixed profile was shown in 9/103 samples, which impeded species identification. In conclusion, the infection in these dogs was predominantly due to L. amazonensis, thus indicating that diagnosing of cases of canine leishmaniasis needs to be reexamined, since the causative agent identified is not restricted to L. infantum.

  19. Investigation of the Anti-Leishmania (Leishmania infantum Activity of Some Natural Sesquiterpene Lactones

    Directory of Open Access Journals (Sweden)

    Imke F. Wulsten

    2017-04-01

    Full Text Available Leishmaniases are neglected infectious diseases caused by parasites of the ‘protozoan’ genus Leishmania. Depending on the parasite species, different clinical forms are known as cutaneous, muco-cutaneous, and the visceral leishmaniasis (VL. VL is particularly fatal and the therapy presents limitations. In the search for new anti-leishmanial hit compounds, seven natural sesquiterpene lactones were evaluated against promastigotes and intracellular amastigotes of Leishmania (Leishmania infantum, a pathogen causing VL. The pseudoguaianolides mexicanin I and helenalin acetate demonstrated the highest selectivity and potency against intracellular amastigotes. In addition, promastigotes treated with helenalin acetate were subject to an ultrastructural and biochemical investigation. The lethal action of the compound was investigated by fluorescence-activated cell sorting and related techniques to detect alterations in reactive oxygen species (ROS content, plasma membrane permeability, and mitochondrial membrane potential. Helenalin acetate significantly reduced the mitochondrial membrane potential and the mitochondrial structural damage was also confirmed by transmission electron microscopy, displaying an intense organelle swelling. No alteration of plasma membrane permeability or ROS content could be detected. Additionally, helenalin acetate significantly increased the production of nitric oxide in peritoneal macrophages, probably potentiating the activity against the intracellular amastigotes. Helenalin acetate could hence be a useful anti-leishmanial scaffold for further optimization studies.

  20. Investigation of the Anti-Leishmania (Leishmania) infantum Activity of Some Natural Sesquiterpene Lactones.

    Science.gov (United States)

    Wulsten, Imke F; Costa-Silva, Thais A; Mesquita, Juliana T; Lima, Marta L; Galuppo, Mariana K; Taniwaki, Noemi N; Borborema, Samanta E T; Da Costa, Fernando B; Schmidt, Thomas J; Tempone, Andre G

    2017-04-25

    Leishmaniases are neglected infectious diseases caused by parasites of the 'protozoan' genus Leishmania. Depending on the parasite species, different clinical forms are known as cutaneous, muco-cutaneous, and the visceral leishmaniasis (VL). VL is particularly fatal and the therapy presents limitations. In the search for new anti-leishmanial hit compounds, seven natural sesquiterpene lactones were evaluated against promastigotes and intracellular amastigotes of Leishmania (Leishmania) infantum, a pathogen causing VL. The pseudoguaianolides mexicanin I and helenalin acetate demonstrated the highest selectivity and potency against intracellular amastigotes. In addition, promastigotes treated with helenalin acetate were subject to an ultrastructural and biochemical investigation. The lethal action of the compound was investigated by fluorescence-activated cell sorting and related techniques to detect alterations in reactive oxygen species (ROS) content, plasma membrane permeability, and mitochondrial membrane potential. Helenalin acetate significantly reduced the mitochondrial membrane potential and the mitochondrial structural damage was also confirmed by transmission electron microscopy, displaying an intense organelle swelling. No alteration of plasma membrane permeability or ROS content could be detected. Additionally, helenalin acetate significantly increased the production of nitric oxide in peritoneal macrophages, probably potentiating the activity against the intracellular amastigotes. Helenalin acetate could hence be a useful anti-leishmanial scaffold for further optimization studies.

  1. Leishmania (Leishmania infantum chagasi em canídeos silvestres mantidos em cativeiro, no Estado de Mato Grosso Leishmania (Leishmania infantum chagasi in wild canids kept in captivity in the State of Mato Grosso

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    Nely Pinheiro Souza

    2010-06-01

    Full Text Available INTRODUÇÃO: Leishmaniose visceral é uma zoonose que acomete diversos mamíferos tendo os canídeos domésticos como principais reservatórios em ambiente urbano. A presente nota descreve a infecção de canídeos silvestres por Leishmania (Leishmania infantum chagasi mantidos em cativeiro no Estado de Mato Grosso, Brasil. MÉTODOS: De seis raposas (Cerdocyon thous e um cachorro vinagre (Spheotos venaticus, foram coletadas amostras de pele, medula óssea e linfonodo para detecção e caracterização de Leishmania sp pela técnica de PCR-RFLP. RESULTADOS: Todos as animais pesquisados apresentaram-se positivos para Leishmania (L. infantum chagasi. CONCLUSÕES: Destaca-se a importância de monitoramento adequado dos mesmos, além do maior controle desta enfermidade já que estes animais estão em ambientes de recreação pública.INTRODUCTION: Visceral leishmaniasis is a zoonosis that affects many mammals, and domestic canids are the main reservoirs in urban environments. This note describes infection by Leishmania (Leishmania infantum chagasi among wild canids kept in captivity in the State of Mato Grosso, Brazil. METHODS: Skin, bone marrow and lymph node samples were collected from six crab-eating foxes (Cerdocyon thous and one bush dog (Spheotos venaticus, in order to detect and characterize Leishmania using the PCR-RFLP technique. RESULTS: All the animals studied were positive for Leishmania (L. infantum chagasi. CONCLUSIONS: This study highlights the importance of adequate monitoring of these animals, as well as greater control of this disease, given that these animals are in a public recreation environment.

  2. Leishmania infantum leishmaniasis in corticosteroid – treated patients

    OpenAIRE

    Pittalis, Silvia; Nicastri, Emanuele; Spinazzola, Francesco; Ghirga, Piero; De Marco, Michele; Paglia, Maria Grazia; Narciso, Pasquale

    2006-01-01

    Abstract Background The number of leishmaniasis cases associated with immunosuppression has increased regularly over the past 20 years. Immunosuppression related to HIV infection, immunosuppressive treatment, organ transplantation, and neoplastic diseases increases the risk for Leishmania-infected people to develop visceral illness. Case presentation Three cases of Leishmania infantum leishmaniasis in corticosteroid (CS)-treated patients are reported: an isolated lingual leishmaniasis in a fa...

  3. An overview on Leishmania vaccines: A narrative review article

    OpenAIRE

    REZVAN, Hossein; MOAFI, Mohammad

    2015-01-01

    Leishmaniasis is one of the major health problems and categorized as a class I disease (emerging and uncontrolled) by World Health Organization (WHO), causing highly significant morbidity and mortality. Indeed, more than 350 million individuals are at risk of Leishmania infection, and about 1.6 million new cases occur causing more than 50 thousands death annually. Because of the severe toxicity and drug resistance, present chemotherapy regimen against diverse forms of Leishmania infections is...

  4. Subversion and Utilization of Host Innate Defense by Leishmania amazonensis

    OpenAIRE

    Soong, Lynn

    2012-01-01

    Infection with Leishmania amazonensis and other members of the Leishmania mexicana complex can lead to diverse clinical manifestations, some of which are relatively difficult to control, even with standard chemotherapy. Diffuse cutaneous leishmaniasis (CL) is a rare but severe form, and its clinical hallmark is excessive parasitic growth in infected cells accompanied by profound impairments in host immune responses to the parasites. Since these parasites also cause non-healing CL in most inbr...

  5. Efficacy of a diarylheptanoid derivative against Leishmania amazonensis

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    Alves Luciana Vignólio

    2003-01-01

    Full Text Available The activity of several diarylheptanoid derivatives (curcuminoids was previously evaluated against Leishmania amazonensis promastigotes and among them the most active compound was the [1-(4-methoxy-phenyl-7-(3,4-methoxy-4-hydroxy-phenyl-1,6-heptadien-3, 5-dione]. This derivative was chosen to be assayed in vivo in a treatment trial. For these experiments, the curcuminoid compound was used in a concentration equivalent to the IC50/24 h, obtained from the previous study. Balb/c mice were inoculated subcutaneously in the footpad with L. amazonensis infective promastigotes and 4 weeks after the inoculation, the animals were treated with different schemes, varying from 1 to 3 doses. In all the experiments, Pentamidine Isethionate was used as reference drug under the same experimental conditions. The results showed that one dose was not enough to heal the lesion, however, with 2 and 3 doses the efficiency of the assayed compound was clear. On the other hand, treatment with Pentamidine Isethionate using the three different schemes was not satisfactory when compared to the curcuminoid derivative.

  6. Calcein+/PI- as an early apoptotic feature in Leishmania.

    Science.gov (United States)

    Basmaciyan, Louise; Azas, Nadine; Casanova, Magali

    2017-01-01

    Although leishmaniases are responsible for high morbidity and mortality all over the world, no really satisfying treatment exists. Furthermore, the corresponding parasite Leishmania undergoes a very characteristic form of programmed cell death. Indeed, different stimuli can induce morphological and biochemical apoptotic-like features. However, the key proteins involved in mammal apoptosis, such as caspases and death receptors, are not encoded in the genome of this parasite. Currently, little is known about Leishmania apoptosis, notably owing to the lack of specific tools for programmed cell death analysis in these parasites. Furthermore, there is a need for a better understanding of Leishmania programmed cell death in order (i) to better understand the role of apoptosis in unicellular organisms, (ii) to better understand apoptosis in general through the study of an ancestral eukaryote, and (iii) to identify new therapeutic targets against leishmaniases. To advance understanding of apoptosis in Leishmania, in this study we developed a new tool based on the quantification of calcein and propidium iodide by flow cytometry. This double labeling can be employed to distinguish early apoptosis, late apoptosis and necrosis in Leishmania live cells with a very simple and rapid assay. This paper should, therefore, be of interest for people working on Leishmania and related parasites.

  7. Asymptomatic dogs are highly competent to transmit Leishmania (Leishmania) infantum chagasi to the natural vector.

    Science.gov (United States)

    Laurenti, Márcia Dalastra; Rossi, Claudio Nazaretian; da Matta, Vânia Lúcia Ribeiro; Tomokane, Thaise Yumie; Corbett, Carlos Eduardo Pereira; Secundino, Nágila Francinete Costa; Pimenta, Paulo Filemon Paulocci; Marcondes, Mary

    2013-09-23

    We evaluated the ability of dogs naturally infected with Leishmania (Leishmania) infantum chagasi to transfer the parasite to the vector and the factors associated with transmission. Thirty-eight infected dogs were confirmed to be infected by direct observation of Leishmania in lymph node smears. Dogs were grouped according to external clinical signs and laboratory data into symptomatic (n=24) and asymptomatic (n=14) animals. All dogs were sedated and submitted to xenodiagnosis with F1-laboratory-reared Lutzomyia longipalpis. After blood digestion, sand flies were dissected and examined for the presence of promastigotes. Following canine euthanasia, fragments of skin, lymph nodes, and spleen were collected and processed using immunohistochemistry to evaluate tissue parasitism. Specific antibodies were detected using an enzyme-linked immunosorbent assay. Antibody levels were found to be higher in symptomatic dogs compared to asymptomatic dogs (p=0.0396). Both groups presented amastigotes in lymph nodes, while skin parasitism was observed in only 58.3% of symptomatic and in 35.7% of asymptomatic dogs. Parasites were visualized in the spleens of 66.7% and 71.4% of symptomatic and asymptomatic dogs, respectively. Parasite load varied from mild to intense, and was not significantly different between groups. All asymptomatic dogs except for one (93%) were competent to transmit Leishmania to the vector, including eight (61.5%) without skin parasitism. Sixteen symptomatic animals (67%) infected sand flies; six (37.5%) showed no amastigotes in the skin. Skin parasitism was not crucial for the ability to infect Lutzomyia longipalpis but the presence of Leishmania in lymph nodes was significantly related to a positive xenodiagnosis. Additionally, a higher proportion of infected vectors that fed on asymptomatic dogs was observed (p=0.0494). Clinical severity was inversely correlated with the infection rate of sand flies (p=0.027) and was directly correlated with antibody

  8. immune response in human leishmania infections Respuesta inmune en infecciones humanas por Leishmania spp

    Directory of Open Access Journals (Sweden)

    Sara María Robledo Restrepo

    2000-03-01

    Full Text Available This review summarizes relevant information about the immune response triggered during leishmaniosis, a disease of great importance from the epidemiological point of view, since it is endemic in Colombia and other countries. We emphasize on human leishmaniosis; nevertheless, some important findings in the murine model are also mentioned. This information allows to conclude that Leishmania infection is a complex and coordinated process, which includes adhesion and entrance of the parasite into the host cells and its survival inside them. Events that mediate the infection process may influence its result in terms of elimination of the parasite or development of the disease, through induction or not of an effective specific immune response which involves host cell activation and parasite destruction. La presente revisión tiene como objetivo resumir la información más relevante acerca de la respuesta inmune que se desencadena durante la leishmaniosis, una enfermedad de gran importancia desde el punto de vista epidemiológico dado que es endémica en Colombia y otros países. Aunque la respuesta inmune en la leishmaniosis es un tema que se ha estudiado ampliamente en las infecciones por especies de Leishmania del Viejo Mundo, particularmente Leishmania major y Leishmania donovani y en el modelo murino, la presente revisión hace énfasis en la leishmaniosis humana. Algunos hallazgos importantes en el modelo murino también se mencionan. La información contenida en la revisión, en su mayoría, proviene de publicaciones derivadas de investigaciones, las cuales se seleccionaron con base en la calidad del trabajo realizado y en los aportes de sus resultados en el avance del conocimiento sobre las infecciones en humanos. La síntesis de la información seleccionada nos permite concluir que la infección por Leishmania es un proceso complejo y coordinado que incluye la adherencia y entrada del parásito a la célula hospedera y su posterior

  9. Leishmaniose cutânea na Amazônia: registro do primeiro caso humano de infecção mista, determinado por duas espécies distintas de Leishmnias: Leishmania brasiliensis e Leishmania mexicana amazonensis

    Directory of Open Access Journals (Sweden)

    F. T. Silveira

    1984-10-01

    Full Text Available Fez-se o registro, na Amazônia, do primeiro caso humano de infecção cutânea mista determinada por duas espécies distintas de Leishmania: a Leishmania braziliensis braziliensis e a Leishmania mexicana amazonensis. As duas amostras, em questão, foram isoladas de lesões distintas de um mesmo paciente, e a caracterização das espécies foi feita com base em observações de infecção experimental em hamsters, comportamento em meios artificiais de cultura, desenvolvimento de infecção experimental em Lutzomyia longipalpis, e eletroforese de isoenzimas em gel de amido. Conclui-se ser de interesse o achado que, combinado com o fato já conhecido de ausência de imunidade cruzada entre a maioria das leishmânias, sugere a necessidade do emprego de uma vacina polivalente para a região.

  10. Case Report: First Case of Cutaneous Leishmaniasis Caused by Leishmania (Viannia) braziliensis in Suriname

    NARCIS (Netherlands)

    Hu, Ricardo V. P. F.; Kent, Alida D.; Adams, Emily R.; van der Veer, Charlotte; Sabajo, Leslie O. A.; Mans, Dennis R. A.; de Vries, Henry J. C.; Schallig, Henk D. F. H.; Fat, Rudy F. M. Lai A.

    2012-01-01

    The main causative agent of cutaneous leishmaniasis (CL) in Suriname is Leishmania (Viannia) guyanensis. This case report presents a patient infected with Leishmania (Viannia) braziliensis, a species never reported before in Suriname. This finding has clinical implications, because L. braziliensis

  11. Quantification of anti-Leishmania antibodies in saliva of dogs.

    Science.gov (United States)

    Cantos-Barreda, Ana; Escribano, Damián; Bernal, Luis J; Cerón, José J; Martínez-Subiela, Silvia

    2017-08-15

    Detection of serum anti-Leishmania antibodies by quantitative or qualitative techniques has been the most used method to diagnose Canine Leishmaniosis (CanL). Nevertheless, saliva may represent an alternative to blood because it is easy to collect, painless and non-invasive in comparison with serum. In this study, two time-resolved immunofluorometric assays (TR-IFMAs) for quantification of anti-Leishmania IgG2 and IgA antibodies in saliva were developed and validated and their ability to distinguish Leishmania-seronegative from seropositive dogs was evaluated. The analytical study was performed by evaluation of assay precision, sensitivity and accuracy. In addition, serum from 48 dogs (21 Leishmania-seropositive and 27 Leishmania-seronegative) were analyzed by TR-IFMAs. The assays were precise, with an intra- and inter-assay coefficients of variation lower than 11%, and showed high level of accuracy, as determined by linearity under dilution (R2=0.99) and recovery tests (>88.60%). Anti-Leishmania IgG2 antibodies in saliva were significantly higher in the seropositive group compared with the seronegative (pLeishmania IgA antibodies between both groups were observed. Furthermore, TR-IFMA for quantification of anti-Leishmania IgG2 antibodies in saliva showed higher differences between seropositive and seronegative dogs than the commercial assay used in serum. In conclusion, TR-IFMAs developed may be used to quantify anti-Leishmania IgG2 and IgA antibodies in canine saliva with an adequate precision, analytical sensitivity and accuracy. Quantification of anti-Leishmania IgG2 antibodies in saliva could be potentially used to evaluate the humoral response in CanL. However, IgA in saliva seemed not to have diagnostic value for this disease. For future studies, it would be desirable to evaluate the ability of the IgG2 assay to detect dogs with subclinical disease or with low antibody titers in serum and also to study the antibodies behaviour in saliva during the treatment

  12. Proteomic analysis of the soluble proteomes of miltefosine-sensitive and -resistant Leishmania infantum chagasi isolates obtained from Brazilian patients with different treatment outcomes.

    Science.gov (United States)

    Carnielli, Juliana B T; de Andrade, Hélida M; Pires, Simone F; Chapeaurouge, Alexander D; Perales, Jonas; Monti-Rocha, Renata; Carvalho, Sílvio F G; Ribeiro, Leonardo P; Dietze, Reynaldo; Figueiredo, Suely G; Lemos, Elenice M

    2014-08-28

    The mechanism of miltefosine-resistance in Leishmania spp. has been partially determined in experimental resistant lines; however, studies using clinical isolates with different miltefosine susceptibilities are still needed. In our study, we used a proteomic 2D-DIGE/MS approach to study different protein abundances in miltefosine-sensitive and -resistant Leishmania infantum chagasi isolates from visceral leishmaniasis patients with different miltefosine treatment outcomes. The high-resolution proteome obtained from these isolates showed 823 matched spots and 46 spots exhibited different abundances between the isolates. Out of these differentially expressed spots, 26 (56.5%) showed greater and 20 (43.5%) showed lower expression of the resistant isolate compared to the sensitive isolate. MALDI/TOF-TOF mass spectrometry allowed the identification of 32 spots with unique protein identification correspondent to 22 non-redundant proteins. Most of the proteins up-regulated in the proteome miltefosine-resistant isolates were associated with redox homeostasis, stress response, protection to apoptosis, and drug translocation. These differentially expressed proteins are likely involved in miltefosine natural resistance and suggest that the miltefosine-resistance mechanism in Leishmania is multifactorial. Visceral leishmaniasis (VL) is a serious disease with a challenging treatment plan requiring the prolonged and painful applications of poorly tolerated toxic drugs. Therefore, the identification of miltefosine, an effective and safe oral drug, was considered a significant advancement in leishmaniasis therapy. However, different sensitivities to miltefosine in Leishmania have been observed in clinically relevant species, and the biological mechanism by which clinical isolates of Leishmania acquire drug resistance is poorly understood. Our work aims to elucidate the mechanism of natural resistance to miltefosine in Leishmania by studying the isolates from VL patients who

  13. Leishmaniasis in Turkey: Visceral and cutaneous leishmaniasis caused by Leishmania donovani in Turkey.

    Science.gov (United States)

    Özbilgin, Ahmet; Harman, Mehmet; Karakuş, Mehmet; Bart, Aldert; Töz, Seray; Kurt, Özgür; Çavuş, İbrahim; Polat, Erdal; Gündüz, Cumhur; Van Gool, Tom; Özbel, Yusuf

    2017-09-01

    In Turkey, the main causative agents are Leishmania tropica (L. tropica) and Leishmania infantum (L. infantum) for cutaneous leishmaniasis (CL) and L. infantum for visceral leishmaniasis (VL). In this study, we investigated leishmaniasis cases caused by L. donovani and established animal models for understanding its tropism in in vivo conditions. Clinical samples (lesion aspirations and bone marrow) obtained from CL/VL patients were investigated using parasitological (smear/NNN) and DNA-based techniques. For species identification, a real time ITS1-PCR was performed using isolates and results were confirmed by hsp70 PCR-N/sequencing and cpb gene PCR/sequencing in order to reveal Leishmania donovani and Leishmania infantum discrimination. Clinical materials from CL and VL patients were also inoculated into two experimental groups (Group CL and Group VL) of Balb/C mice intraperitoneally for creating clinical picture of Turkish L. donovani strains. After 45days, the samples from visible sores of the skin were taken, and spleens and livers were removed. Measurements of the internal organs were done and touch preparations were prepared for checking the presence of amastigotes. The strains were isolated from all patients and amastigotes were seen in all smears of the patients, and then isolates were immediately stored in liquid nitrogen. In real time ITS1-PCR, the melting temperatures of all samples were out of range of L. infantum, L. tropica and L. major. Sequencing of hsp70 PCR-N showed that all isolates highly identical to previously submitted L. donovani sequences in GenBank, and cpb gene sequencing showed five isolates had longer cpbF allele, whereas one isolate contained a mixed sequence of both cpbF and cpbE. All mice in both experimental groups became infected. Compared to controls, the length and width of both liver and spleen were significantly elevated (pTurkey. Animal models using clinical samples were successfully established and important clinical

  14. Exposure of phosphatidylserine on Leishmania amazonensis isolates is associated with diffuse cutaneous leishmaniasis and parasite infectivity.

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    Jaqueline França-Costa

    Full Text Available Diffuse cutaneous leishmaniasis (DCL is a rare clinical manifestation of leishmaniasis, characterized by an inefficient parasite-specific cellular response and heavily parasitized macrophages. In Brazil, Leishmania (Leishmania amazonensis is the main species involved in DCL cases. In the experimental model, recognition of phosphatidylserine (PS molecules exposed on the surface of amastigotes forms of L. amazonensis inhibits the inflammatory response of infected macrophages as a strategy to evade the host immune surveillance. In this study, we examined whether PS exposure on L. amazonensis isolates from DCL patients operated as a parasite pathogenic factor and as a putative suppression mechanism of immune response during the infection. Peritoneal macrophages from F1 mice (BALB/c×C57BL/6 were infected with different L. amazonensis isolates from patients with localized cutaneous leishmaniasis (LCL or DCL. DCL isolates showed higher PS exposure than their counterparts from LCL patients. In addition, PS exposure was positively correlated with clinical parameters of the human infection (number of lesions and time of disease and with characteristics of the experimental infection (macrophage infection and anti-inflammatory cytokine induction. Furthermore, parasites isolated from DCL patients displayed an increased area in parasitophorous vacuoles (PV when compared to those isolated from LCL patients. Thus, this study shows for the first time that a parasite factor (exposed PS might be associated with parasite survival/persistence in macrophages and lesion exacerbation during the course of DCL, providing new insights regarding pathogenic mechanism in this rare chronic disease.

  15. COMPARATIVE STUDIES OF HERPETOMONADS AND LEISHMANIAS

    Science.gov (United States)

    Noguchi, Hideyo; Tilden, Evelyn B.

    1926-01-01

    obtained in culture, all the strains grow well on leptospira medium, as well as on blood slants. Growth takes place both at 26°C. and at 37°. The morphology of the organisms is considerably modified by cultivation. This is especially true of the plant flagellates. In the latex they have ribbon-like bodies, often twisted, and comparatively short flagella; the protoplasm is clear, almost hyaline. The flagellates seen in the gut and feces of insects are usually large, slender organisms, with flagella as long as or even longer than the body, which contains numerous volutin granules in the cytoplasm. In cultures under parallel conditions the flagellates from both these sources become shorter and thicker, the plant forms no longer appear flat and ribbon-like, and in general the organisms approach one another in morphological features. Even in the case of the least modified insect flagellates, i.e. those from flies, there is never exact correspondence between the natural and the cultivated forms. The morphological features of the cultivated flagellates vary according to the medium on which the organisms are grown and the age of the culture. The flagellates grown on the surface of blood slants are pyriform, with truncated anterior portion, and short flagellum; in the condensation water, however, the individuals are elongated and have long active flagella. On the leptospira medium the slender active forms with long flagella predominate. In the presence of fermentable carbohydrate, or in medium containing considerable acid, peculiar bifurcated or multifurcated individuals are seen. Similar forms have been seen under natural conditions. Cultures of Leishmania behave in the same way under the conditions described. There is a striking difference in rapidity of growth between the organisms isolated by us and the leishmanias, H. ctenocephali, and T. rotatorium. While the stock cultures of the group first mentioned multiply rapidly at 37°C., growth becoming visible within 24 hours, the

  16. Neutrophils reduce the parasite burden in Leishmania (Leishmania amazonensis-infected macrophages.

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    Erico Vinícius de Souza Carmo

    Full Text Available BACKGROUND: Studies on the role of neutrophils in Leishmania infection were mainly performed with L. (L major, whereas less information is available for L. (L amazonensis. Previous results from our laboratory showed a large infiltrate of neutrophils in the site of infection in a mouse strain resistant to L. (L. amazonensis (C3H/HePas. In contrast, the susceptible strain (BALB/c displayed a predominance of macrophages harboring a high number of amastigotes and very few neutrophils. These findings led us to investigate the interaction of inflammatory neutrophils with L. (L. amazonensis-infected macrophages in vitro. METHODOLOGY/PRINCIPAL FINDINGS: Mouse peritoneal macrophages infected with L. (L. amazonensis were co-cultured with inflammatory neutrophils, and after four days, the infection was quantified microscopically. Data are representative of three experiments with similar results. The main findings were 1 intracellular parasites were efficiently destroyed in the co-cultures; 2 the leishmanicidal effect was similar when cells were obtained from mouse strains resistant (C3H/HePas or susceptible (BALB/c to L. (L. amazonensis; 3 parasite destruction did not require contact between infected macrophages and neutrophils; 4 tumor necrosis factor alpha (TNF-α, neutrophil elastase and platelet activating factor (PAF were involved with the leishmanicidal activity, and 5 destruction of the parasites did not depend on generation of oxygen or nitrogen radicals, indicating that parasite clearance did not involve the classical pathway of macrophage activation by TNF-α, as reported for other Leishmania species. CONCLUSIONS/SIGNIFICANCE: The present results provide evidence that neutrophils in concert with macrophages play a previously unrecognized leishmanicidal effect on L. (L. amazonensis. We believe these findings may help to understand the mechanisms involved in innate immunity in cutaneous infection by this Leishmania species.

  17. Identification of geographically distributed sub-populations of Leishmania (Leishmania major by microsatellite analysis

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    Schwenkenbecher Jan

    2008-06-01

    Full Text Available Abstract Background Leishmania (Leishmania major, one of the agents causing cutaneous leishmaniasis (CL in humans, is widely distributed in the Old World where different species of wild rodent and phlebotomine sand fly serve as animal reservoir hosts and vectors, respectively. Despite this, strains of L. (L. major isolated from many different sources over many years have proved to be relatively uniform. To investigate the population structure of the species highly polymorphic microsatellite markers were employed for greater discrimination among it's otherwise closely related strains, an approach applied successfully to other species of Leishmania. Results Multilocus Microsatellite Typing (MLMT based on 10 different microsatellite markers was applied to 106 strains of L. (L. major from different regions where it is endemic. On applying a Bayesian model-based approach, three main populations were identified, corresponding to three separate geographical regions: Central Asia (CA; the Middle East (ME; and Africa (AF. This was congruent with phylogenetic reconstructions based on genetic distances. Re-analysis separated each of the populations into two sub-populations. The two African sub-populations did not correlate well with strains' geographical origin. Strains falling into the sub-populations CA and ME did mostly group according to their place of isolation although some anomalies were seen, probably, owing to human migration. Conclusion The model- and distance-based analyses of the microsatellite data exposed three main populations of L. (L. major, Central Asia, the Middle East and Africa, each of which separated into two sub-populations. This probably correlates with the different species of rodent host.

  18. Phylogenetic analysis of HSP70 and cyt b gene sequences for Chinese Leishmania isolates and ultrastructural characteristics of Chinese Leishmania sp.

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    Yuan, Dongmei; Qin, Hanxiao; Zhang, Jianguo; Liao, Lin; Chen, Qiwei; Chen, Dali; Chen, Jianping

    2017-02-01

    Leishmaniasis is a worldwide epidemic disease caused by the genus Leishmania, which is still endemic in the west and northwest areas of China. Some viewpoints of the traditional taxonomy of Chinese Leishmania have been challenged by recent phylogenetic researches based on different molecular markers. However, the taxonomic positions and phylogenetic relationships of Chinese Leishmania isolates remain controversial, which need for more data and further analysis. In this study, the heat shock protein 70 (HSP70) gene and cytochrome b (cyt b) gene were used for phylogenetic analysis of Chinese Leishmania isolates from patients, dogs, gerbils, and sand flies in different geographic origins. Besides, for the interesting Leishmania sp. in China, the ultrastructure of three Chinese Leishmania sp. strains (MHOM/CN/90/SC10H2, SD, GL) were observed by transmission electron microscopy. Bayesian trees from HSP70 and cyt b congruently indicated that the 14 Chinese Leishmania isolates belong to three Leishmania species including L. donovani complex, L. gerbilli, and L. (Sauroleishmania) sp. Their identity further confirmed that the undescribed Leishmania species causing visceral Leishmaniasis (VL) in China is closely related to L. tarentolae. The phylogenetic results from HSP70 also suggested the classification of subspecies within L. donovani complex: KXG-918, KXG-927, KXG-Liu, KXG-Xu, 9044, SC6, and KXG-65 belong to L. donovani; Cy, WenChuan, and 801 were proposed to be L. infantum. Through transmission electron microscopy, unexpectedly, the Golgi apparatus were not observed in SC10H2, SD, and GL, which was similar to previous reports of reptilian Leishmania. The statistical analysis of microtubule counts separated SC10H2, SD, and GL as one group from any other reference strain (L. donovani MHOM/IN/80/DD8; L. tropica MHOM/SU/74/K27; L. gerbilli MRHO/CN/60/GERBILLI). The ultrastructural characteristics of Leishmania sp. partly lend support to the phylogenetic inference that

  19. Leishmania major infection in humanized mice induces systemic infection and provokes a nonprotective human immune response.

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    Anja Kathrin Wege

    Full Text Available BACKGROUND: Leishmania (L. species are the causative agent of leishmaniasis. Due to the lack of efficient vaccine candidates, drug therapies are the only option to deal with cutaneous leishmaniasis. Unfortunately, chemotherapeutic interventions show high toxicity in addition to an increased risk of dissemination of drug-resistant parasites. An appropriate laboratory animal based model is still missing which allows testing of new drug strategies in the context of human immune cells in vivo. METHODOLOGY/PRINCIPAL FINDINGS: Humanized mice were infected subcutaneously with stationary phase promastigote L. major into the footpad. The human immune response against the pathogen and the parasite host interactions were analyzed. In addition we proved the versatility of this new model to conduct drug research studies by the inclusion of orally given Miltefosine. We show that inflammatory human macrophages get infected with Leishmania parasites at the site of infection. Furthermore, a Leishmania-specific human-derived T cell response is initiated. However, the human immune system is not able to prevent systemic infection. Thus, we treated the mice with Miltefosine to reduce the parasitic load. Notably, this chemotherapy resulted in a reduction of the parasite load in distinct organs. Comparable to some Miltefosine treated patients, humanized mice developed severe side effects, which are not detectable in the classical murine model of experimental leishmaniasis. CONCLUSIONS/SIGNIFICANCE: This study describes for the first time L. major infection in humanized mice, characterizes the disease development, the induction of human adaptive and innate immune response including cytokine production and the efficiency of Miltefosine treatment in these animals. In summary, humanized mice might be beneficial for future preclinical chemotherapeutic studies in systemic (visceral leishmaniasis allowing the investigation of human immune response, side effects of the drug

  20. Insights into the phosphatidylcholine and phosphatidylethanolamine biosynthetic pathways in Leishmania parasites and characterization of a choline kinase from Leishmania infantum.

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    Pulido, Sergio A; Nguyen, Victoria H; Alzate, Juan F; Cedeño, David L; Makurath, Monika A; Ríos-Vásquez, Amalia; Duque-Benítez, Sandra M; Jones, Marjorie A; Robledo, Sara M; Friesen, Jon A

    2017-11-01

    The protozoan parasite Leishmania infantum is a causative agent of the disease visceral leishmaniasis, which can be fatal if not properly treated. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) biosynthesis pathways are attractive targets for new antileishmanial compounds since these Leishmania cell membrane phospholipids are important for parasite morphology and physiology. In this work we observed Leishmania synthesize PC and PE from extracellular choline and ethanolamine, respectively, suggesting the presence of CDP-choline and CDP-ethanolamine pathways. In addition, Leishmania converted PE to PC, indicating the parasite possesses phosphatidylethanolamine N-methyltransferase (PEMT) activity. The first step in the biosynthesis of PC or PE requires the phosphorylation of choline or ethanolamine by a kinase. We cloned the gene encoding a putative choline/ethanolamine kinase from Leishmania infantum and expressed and purified the encoded recombinant protein. The enzyme possesses choline kinase activity with a Vmax of 3.52μmol/min/mg and an apparent Km value of 0.089mM with respect to choline. The enzyme can also phosphorylate ethanolamine in vitro, but the apparent Km for ethanolamine is 850-fold greater than for choline. In an effort to probe requirements for small molecule inhibition of Leishmania choline kinase, the recombinant enzyme was evaluated for the ability to be inhibited by novel quaternary ammonium salts. The most effective inhibitor was N-iodomethyl-N,N,-dimethyl-N-(6,6-diphenyl hex-5-en-1-yle) ammonium iodide, denoted compound C6. In the presence of 4mM compound C6, the Vmax/Km decreased to approximately 1% of the wild-type catalytic efficiency. In addition, in Leishmania cells treated with compound C6 choline transport was inhibited. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Peptone-yeast autolysate-fetal bovine serum 10, a simple, inexpensive liquid medium for cultivation of Leishmania spp.

    OpenAIRE

    Palomino, J. C.

    1982-01-01

    A simple liquid medium for the cultivation of Leishmania parasites is described. Leishmania brasiliensis and Leishmania peruviana cultured in this medium reached cell densities greater than 10(7) promastigotes per ml within 7 days. This medium compares very favorably with the more complex media used to cultivate Leishmania spp. and other hemoflagellates.

  2. Mechanism of ascaridole activation in Leishmania.

    Science.gov (United States)

    Geroldinger, Gerald; Tonner, Matthias; Hettegger, Hubert; Bacher, Markus; Monzote, Lianet; Walter, Martin; Staniek, Katrin; Rosenau, Thomas; Gille, Lars

    2017-05-15

    Endoperoxides (EP) are an emerging class of drugs which have potential in antiparasitic therapy, but also in other fields. For malaria therapy the EP artemisinin (Art) and its derivatives are successfully used. We have shown in the past that the EP ascaridole (Asc) is useful for the treatment of cutaneous leishmaniasis in a mouse model. Biomimetic experiments suggested that these drugs need activation in the respective target pathogens to exert their function. In spite of this idea, direct activation of EP to radicals inside cells has never been demonstrated. Therefore, this study was initiated to explore the activation of Asc in biomimetic systems and inside Leishmania in comparison to Art. Using electron paramagnetic resonance spectroscopy (EPR) in combination with spin-trapping we identified the secondary alkyl radical intermediates arising from reduction by Fe2+ in cell-free systems. Combined GC/NMR analysis confirmed the loss of isopropyl residues from Asc during this process as intermediates. This activation of Asc was stimulated by low molecular Fe2+ complexes or alternatively by hemin in conjunction with thiol reductants, such as cysteine (Cys). In Leishmania tarentolae promastigotes (LtP) as model for pathogenic forms of Leishmania carbon-centered radicals were identified in the presence of Asc by EPR spin-trapping. Both Asc and Art inhibited the viability in LtP with IC50 values in the low micromolar range while IC50 values for J774 macrophages were considerably higher. A similar structure without EP bridge (1,4-cineole) resulted in no detectable radicals and possessed much less cytotoxicity in LtP and no selectivity for LtP compared to J774 cells. The Asc-derived radical formation in LtP was inhibited by the iron chelator deferoxamine (DFO), and stimulated by Cys (a suitable reductant for hemin). The IC50 values for LtP viability in the presence of Asc or Art were increased significantly by the spin trap DMPO, while Cys and DFO increased only IC50 values

  3. T-cell-derived cytokines, nitric oxide production by peripheral blood monocytes and seric anti-Leishmania (Leishmania) chagasi IgG subclass patterns following immunization against canine visceral leishmaniasis using Leishvaccine and Leishmune.

    Science.gov (United States)

    Araújo, Márcio Sobreira Silva; de Andrade, Renata Aline; Sathler-Avelar, Renato; Teixeira-Carvalho, Andréa; Andrade, Mariléia Chaves; Vianna, Leonardo Rocha; Mayrink, Wilson; Reis, Alexandre Barbosa; Malaquias, Luiz Cosme Cotta; Mello, Maria Norma; Martins-Filho, Olindo Assis

    2009-02-11

    It is generally accepted that distinct cytokine expression by the cellular immune response plays a critical role during the outcome of experimental as well as natural canine visceral Leishmaniasis (CVL). Despite the fact that immunoprophylaxis of CVL has become an important control strategy and protective immunity has been reported upon immunization with whole as well as purified Leishmania antigens, the cytokine profile of T-cells triggered by anti-CVL vaccines still remain to be determined. Herein, we have developed a cross-sectional analysis of German Shepherd dogs submitted to vaccination protocols with Leishvaccine (n=6) and Leishmune (n=6). Our data identified distinct immunological profiles elicited by Leishvaccine and Leishmune, with the Leishvaccine triggering a mixed, IFN-gamma and IL-4, cytokine pattern in addition to high levels of anti-Leishmania IgG1, whereas the Leishmune induced an immunological pattern characterized by enhanced levels of IFN-gamma, NO and anti-Leishmania chagasi IgG2. It was important to notice that despite the distinct immunological patterns triggered by Leishvaccine and Leishmune, the ability of both immunobiologicals to activate T-cell-derived IFN-gamma synthesis further suggesting their immunogenic potential against CVL. These findings added support to our hypothesis that both antigenic composition (whole antigen in Leishvaccine versus purified antigen in Leishmune) as well as the adjuvant nature (BGC and saponin) used for the vaccine formulation may count for the distinct activation pattern observed.

  4. Chronic interstitial pneumonitis in dogs naturally infected with Leishmania (Leishmania) chagasi: a histopathological and morphometric study.

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    Gonçalves, Ricardo; Tafuri, Washington Luiz; Melo, Maria Norma de; Raso, Pedro; Tafuri, Wagner Luiz

    2003-01-01

    Eighteen mongrel dogs of unknown age and naturally infected with Leishmania (Leishmania) chagasi, were obtained from the City Hall of Belo Horizonte, Brazil. Four dogs were used as control. Lung samples were obtained and immediately fixed in formalin. The histopathological picture of all lung tissue sections was a chronic and diffuse interstitial pneumonitis. The thickened inter-alveolar septa were characterized by the cellular exudate (mostly macrophages, lymphocytes and plasmocytes) associated with collagen deposition. Morphometric analysis showed greater septal thickness in the infected animals than in controls. In fact, the morphometric study of collagen stained with ammoniac silver confirmed a larger deposition of collagen in the infected animals. The parasitologic method was carried out during the study of the lesions on the slides. However, we did not observe any correlation between the histopathologic and morphometric data and the clinical status of the animals. We conclude that the pulmonary lesions observed in all naturally infected dogs were correlated with the disease and that the morphometric method used was satisfactory for the analysis of septal thickness and of increased collagen deposition, confirming the presence of fibrosis.

  5. Chronic interstitial pneumonitis in dogs naturally infected with Leishmania (Leishmania chagasi: a histopathological and morphometric study

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    Gonçalves Ricardo

    2003-01-01

    Full Text Available Eighteen mongrel dogs of unknown age and naturally infected with Leishmania (Leishmania chagasi, were obtained from the City Hall of Belo Horizonte, Brazil. Four dogs were used as control. Lung samples were obtained and immediately fixed in formalin. The histopathological picture of all lung tissue sections was a chronic and diffuse interstitial pneumonitis. The thickened inter-alveolar septa were characterized by the cellular exudate (mostly macrophages, lymphocytes and plasmocytes associated with collagen deposition. Morphometric analysis showed greater septal thickness in the infected animals than in controls. In fact, the morphometric study of collagen stained with ammoniac silver confirmed a larger deposition of collagen in the infected animals. The parasitologic method was carried out during the study of the lesions on the slides. However, we did not observe any correlation between the histopathologic and morphometric data and the clinical status of the animals. We conclude that the pulmonary lesions observed in all naturally infected dogs were correlated with the disease and that the morphometric method used was satisfactory for the analysis of septal thickness and of increased collagen deposition, confirming the presence of fibrosis.

  6. Rattus norvegicus (Rodentia: Muridae Infected by Leishmania (Leishmania infantum (syn. Le. chagasi in Brazil

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    Fabiana de Oliveira Lara-Silva

    2014-01-01

    Full Text Available In the present study we surveyed the fauna of phlebotomine sand flies and small mammals in peridomestic areas from a Brazilian municipality where the American cutaneous leishmaniasis (ACL is endemic. A total of 608 female phlebotomine sand flies were captured during nine months in 2009 and 2010. Seven different species were represented with 60% of them being Lutzomyia intermedia and Lu. whitmani, both incriminated vectors of ACL. Lu. longipalpis, a proven vector of visceral leishmaniasis (VL was also captured at high proportion (12.8%. Genomic DNA analysis of 136 species-specific pools of female sand flies followed by molecular genotyping showed the presence of Leishmania infantum DNA in two pools of Lu. longipalpis. The same Leishmania species was found in one blood sample from Rattus norvegicus among 119 blood and tissue samples analysed. This is the first report of Le. infantum in R. norvegicus in the Americas and suggests a possible role for this rodent species in the zoonotic cycle of VL. Our study coincided with the reemergence of VL in Governador Valadares.

  7. A vaccine combining two Leishmania braziliensis proteins offers heterologous protection against Leishmania infantum infection.

    Science.gov (United States)

    Duarte, Mariana C; Lage, Daniela P; Martins, Vívian T; Costa, Lourena E; Lage, Letícia M R; Carvalho, Ana Maria R S; Ludolf, Fernanda; Santos, Thaís T O; Roatt, Bruno M; Menezes-Souza, Daniel; Fernandes, Ana Paula; Tavares, Carlos A P; Coelho, Eduardo A F

    2016-08-01

    In the present study, two Leishmania braziliensis proteins, one hypothetical and the eukaryotic initiation factor 5a (EiF5a), were cloned and used as a polyproteins vaccine for the heterologous protection of BALB/c mice against infantum infection. Animals were immunized with the antigens separately or in association, and in both cases saponin was used as an adjuvant. In the results, spleen cells from mice inoculated with the individual or polyproteins vaccine and lately challenged produced significantly higher levels of protein- and parasite-specific IFN-γ, IL-12, and GM-CSF, when both a capture ELISA and flow cytometry assays were performed. Evaluating the parasite load by a limiting dilution as well as by RT-PCR, these animals presented significant reductions in the parasite number in all evaluated organs, when compared to the control (saline and saponin) groups. The best protection was reached when the polyproteins vaccine was employed. Protection was associated with the IFN-γ production against parasite extracts, which was mediated by both CD4(+) and CD8(+) T cells and correlated with the antileishmanial nitrite production. In this context, this vaccine combining two L. braziliensis proteins was able to induce a heterologous protection against VL, and could be considered in future studies to be tested against other Leishmania species or in other mammalian hosts. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Seasonal transmission of Leishmania (Leishmania mexicana in the state of Campeche, Yucatan Peninsula, Mexico

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    Andrade-Narvaez Fernando J

    2003-01-01

    Full Text Available In the Yucatan Peninsula, Mexico, localized cutaneous leishmaniasis (LCL caused by Leishmania (Leishmania mexicana is a typical wild zoonosis restricted to the forest, and humans are only accidentally involved. The transmission of L. (L. mexicana has been related to the patient's occupation: "chicleros"(gum collectors and agricultural workers. The objective of this study was to document L. (L. mexicana seasonally of transmission in endemic areas of LCL in the state of Campeche, Yucatan Peninsula, Mexico. The timing of incidence of LCL in humans during 1993-1994, as well as the rate and time of infection in rodents and sand flies between February 1993 and March 1995 were analyzed. Rodents and sand flies were found infected between November and March, when men carried out their field activities and are exposed. Based on results analyzed, it is concluded that L. (L. mexicana in the endemic area of LCL in the state of Campeche, Yucatan Peninsula, Mexico, presents a seasonal transmission restricted to the months of November to March. The knowledge of the timing of the transmission cycle in an endemic area of leishmaniasis is very important because intervention measures on the high-risk focus and population might be restricted.

  9. Clinical picture of cutaneous leishmaniases due to Leishmania (Leishmania mexicana in the Yucatan peninsula, Mexico

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    Andrade-Narváez Fernando J

    2001-01-01

    Full Text Available Localized cutaneous leishmaniasis (LCL, known as "chiclero's ulcer" in southeast Mexico, was described by Seidelin in 1912. Since then, the sylvatic region of the Yucatan peninsula has been identified as an endemic focus of LCL. The purpose of the present work was to describe the clinical picture of LCL caused by Leishmania (Leishmania mexicana in the Yucatan peninsula. A total of 136 cases of LCL, based on isolation and characterization of L. (L. mexicana by isoenzymes and/or monoclonal antibodies, were selected. Some variability of clinical features regarding number, type, size, form, location and time of evolution of the lesions was observed. The most frequently observed presentation was a single, ulcerated, rounded small lesion, located on the ear, with an evolution time of less than three months, with neither cutaneous metastases nor lymphatic nor mucosal involvement. This picture corresponds to previous studies carried out in the same endemic area where an organism of the L. mexicana complex has been incriminated as a major aetiological agent of classical "chiclero's ulcer", confirming that in the Yucatan peninsula LCL due to L. (L. mexicana when located on the pinna of the ear is a remarkable characteristic.

  10. FIRST REPORT OF CUTANEOUS LEISHMANIASIS CAUSED BY Leishmania (Leishmania) infantum chagasi IN AN URBAN AREA OF RIO DE JANEIRO, BRAZIL.

    Science.gov (United States)

    Lyra, Marcelo Rosandiski; Pimentel, Maria Inês Fernandes; Madeira, Maria de Fátima; Antonio, Liliane de Fátima; Lyra, Janine Pontes de Miranda; Fagundes, Aline; Schubach, Armando de Oliveira

    2015-01-01

    American tegumentary leishmaniasis (ATL) is an infectious disease caused by protozoa of the genus Leishmania, and transmitted by sandflies. In the state of Rio de Janeiro, almost all of the cases of American tegumentary leishmaniasis (ATL) are caused by Leishmania (Viannia) braziliensis, while cases of visceral leishmaniasis (VL) are caused by Leishmania (Leishmania) infantum chagasi. The resurgence of autochthonous VL cases in Rio de Janeiro is related to the geographic expansion of the vector Lutzomyia longipalpis and its ability to adapt to urban areas. We report the first case of leishmaniasis with exclusively cutaneous manifestations caused by L. (L.) infantum chagasi in an urban area of Rio de Janeiro. An eighty-one-year-old woman presented three pleomorphic skin lesions that were not associated with systemic symptoms or visceromegalies. Multilocus enzyme electrophoresis identified L. (L.) infantum chagasi, but direct smear and PCR of bone narrow were negative for Leishmania sp. (suggesting exclusively cutaneous involvement). We discuss the different dermatological presentations of viscerotropic leishmaniasis of the New and Old World, and the clinical and epidemiological importance of the case. Etiologic diagnosis of ATL based upon exclusive clinical criteria may lead to incorrect conclusions. We should be aware of the constant changes in epidemiological patterns related to leishmaniases.

  11. FIRST REPORT OF CUTANEOUS LEISHMANIASIS CAUSED BY Leishmania (Leishmania infantum chagasi IN AN URBAN AREA OF RIO DE JANEIRO, BRAZIL

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    Marcelo Rosandiski LYRA

    2015-10-01

    Full Text Available SUMMARY American tegumentary leishmaniasis (ATL is an infectious disease caused by protozoa of the genus Leishmania, and transmitted by sandflies. In the state of Rio de Janeiro, almost all of the cases of American tegumentary leishmaniasis (ATL are caused by Leishmania (Viannia braziliensis, while cases of visceral leishmaniasis (VL are caused by Leishmania (Leishmania infantum chagasi. The resurgence of autochthonous VL cases in Rio de Janeiro is related to the geographic expansion of the vector Lutzomyia longipalpis and its ability to adapt to urban areas. We report the first case of leishmaniasis with exclusively cutaneous manifestations caused by L. (L. infantum chagasi in an urban area of Rio de Janeiro. An eighty-one-year-old woman presented three pleomorphic skin lesions that were not associated with systemic symptoms or visceromegalies. Multilocus enzyme electrophoresis identified L. (L. infantum chagasi, but direct smear and PCR of bone narrow were negative for Leishmania sp. (suggesting exclusively cutaneous involvement. We discuss the different dermatological presentations of viscerotropic leishmaniasis of the New and Old World, and the clinical and epidemiological importance of the case. Etiologic diagnosis of ATL based upon exclusive clinical criteria may lead to incorrect conclusions. We should be aware of the constant changes in epidemiological patterns related to leishmaniases.

  12. Impact of LbSapSal Vaccine in Canine Immunological and Parasitological Features before and after Leishmania chagasi-Challenge.

    Science.gov (United States)

    Resende, Lucilene Aparecida; Aguiar-Soares, Rodrigo Dian de Oliveira; Gama-Ker, Henrique; Roatt, Bruno Mendes; Mendonça, Ludmila Zanandreis de; Alves, Marina Luiza Rodrigues; Silveira-Lemos, Denise da; Corrêa-Oliveira, Rodrigo; Martins-Filho, Olindo Assis; Araújo, Márcio Sobreira Silva; Fujiwara, Ricardo Toshio; Gontijo, Nelder Figueiredo; Reis, Alexandre Barbosa; Giunchetti, Rodolfo Cordeiro

    2016-01-01

    Dogs represent the most important domestic reservoir of L. chagasi (syn. L. infantum). A vaccine against canine visceral leishmaniasis (CVL) would be an important tool for decreasing the anxiety related to possible L. chagasi infection and for controlling human visceral leishmaniasis (VL). Because the sand fly salivary proteins are potent immunogens obligatorily co-deposited during transmission of Leishmania parasites, their inclusion in an anti-Leishmania vaccine has been investigated in past decades. We investigated the immunogenicity of the "LbSapSal" vaccine (L. braziliensis antigens, saponin as adjuvant, and Lutzomyia longipalpis salivary gland extract) in dogs at baseline (T0), during the post-vaccination protocol (T3rd) and after early (T90) and late (T885) times following L. chagasi-challenge. Our major data indicated that immunization with "LbSapSal" is able to induce biomarkers characterized by enhanced amounts of type I (tumor necrosis factor [TNF]-α, interleukin [IL]-12, interferon [IFN]-γ) cytokines and reduction in type II cytokines (IL-4 and TGF-β), even after experimental challenge. The establishment of a prominent pro-inflammatory immune response after "LbSapSal" immunization supported the increased levels of nitric oxide production, favoring a reduction in spleen parasitism (78.9%) and indicating long-lasting protection against L. chagasi infection. In conclusion, these results confirmed the hypothesis that the "LbSapSal" vaccination is a potential tool to control the Leishmania chagasi infection.

  13. Impact of LbSapSal Vaccine in Canine Immunological and Parasitological Features before and after Leishmania chagasi-Challenge.

    Directory of Open Access Journals (Sweden)

    Lucilene Aparecida Resende

    Full Text Available Dogs represent the most important domestic reservoir of L. chagasi (syn. L. infantum. A vaccine against canine visceral leishmaniasis (CVL would be an important tool for decreasing the anxiety related to possible L. chagasi infection and for controlling human visceral leishmaniasis (VL. Because the sand fly salivary proteins are potent immunogens obligatorily co-deposited during transmission of Leishmania parasites, their inclusion in an anti-Leishmania vaccine has been investigated in past decades. We investigated the immunogenicity of the "LbSapSal" vaccine (L. braziliensis antigens, saponin as adjuvant, and Lutzomyia longipalpis salivary gland extract in dogs at baseline (T0, during the post-vaccination protocol (T3rd and after early (T90 and late (T885 times following L. chagasi-challenge. Our major data indicated that immunization with "LbSapSal" is able to induce biomarkers characterized by enhanced amounts of type I (tumor necrosis factor [TNF]-α, interleukin [IL]-12, interferon [IFN]-γ cytokines and reduction in type II cytokines (IL-4 and TGF-β, even after experimental challenge. The establishment of a prominent pro-inflammatory immune response after "LbSapSal" immunization supported the increased levels of nitric oxide production, favoring a reduction in spleen parasitism (78.9% and indicating long-lasting protection against L. chagasi infection. In conclusion, these results confirmed the hypothesis that the "LbSapSal" vaccination is a potential tool to control the Leishmania chagasi infection.

  14. Impact of LbSapSal Vaccine in Canine Immunological and Parasitological Features before and after Leishmania chagasi-Challenge

    Science.gov (United States)

    Resende, Lucilene Aparecida; Aguiar-Soares, Rodrigo Dian de Oliveira; Gama-Ker, Henrique; Roatt, Bruno Mendes; de Mendonça, Ludmila Zanandreis; Alves, Marina Luiza Rodrigues; da Silveira-Lemos, Denise; Corrêa-Oliveira, Rodrigo; Martins-Filho, Olindo Assis; Araújo, Márcio Sobreira Silva; Fujiwara, Ricardo Toshio; Gontijo, Nelder Figueiredo; Reis, Alexandre Barbosa; Giunchetti, Rodolfo Cordeiro

    2016-01-01

    Dogs represent the most important domestic reservoir of L. chagasi (syn. L. infantum). A vaccine against canine visceral leishmaniasis (CVL) would be an important tool for decreasing the anxiety related to possible L. chagasi infection and for controlling human visceral leishmaniasis (VL). Because the sand fly salivary proteins are potent immunogens obligatorily co-deposited during transmission of Leishmania parasites, their inclusion in an anti-Leishmania vaccine has been investigated in past decades. We investigated the immunogenicity of the “LbSapSal” vaccine (L. braziliensis antigens, saponin as adjuvant, and Lutzomyia longipalpis salivary gland extract) in dogs at baseline (T0), during the post-vaccination protocol (T3rd) and after early (T90) and late (T885) times following L. chagasi-challenge. Our major data indicated that immunization with “LbSapSal” is able to induce biomarkers characterized by enhanced amounts of type I (tumor necrosis factor [TNF]-α, interleukin [IL]-12, interferon [IFN]-γ) cytokines and reduction in type II cytokines (IL-4 and TGF-β), even after experimental challenge. The establishment of a prominent pro-inflammatory immune response after “LbSapSal” immunization supported the increased levels of nitric oxide production, favoring a reduction in spleen parasitism (78.9%) and indicating long-lasting protection against L. chagasi infection. In conclusion, these results confirmed the hypothesis that the “LbSapSal” vaccination is a potential tool to control the Leishmania chagasi infection. PMID:27556586

  15. Drug resistance analysis by next generation sequencing in Leishmania

    Science.gov (United States)

    Leprohon, Philippe; Fernandez-Prada, Christopher; Gazanion, Élodie; Monte-Neto, Rubens; Ouellette, Marc

    2014-01-01

    The use of next generation sequencing has the power to expedite the identification of drug resistance determinants and biomarkers and was applied successfully to drug resistance studies in Leishmania. This allowed the identification of modulation in gene expression, gene dosage alterations, changes in chromosome copy numbers and single nucleotide polymorphisms that correlated with resistance in Leishmania strains derived from the laboratory and from the field. An impressive heterogeneity at the population level was also observed, individual clones within populations often differing in both genotypes and phenotypes, hence complicating the elucidation of resistance mechanisms. This review summarizes the most recent highlights that whole genome sequencing brought to our understanding of Leishmania drug resistance and likely new directions. PMID:25941624

  16. Guns, germs and dogs: On the origin of Leishmania chagasi.

    Science.gov (United States)

    Leblois, Raphaël; Kuhls, Katrin; François, Olivier; Schönian, Gabriele; Wirth, Thierry

    2011-07-01

    The evolutionary history of Leishmania chagasi, the aetiological agent of visceral leishmaniasis in South America has been widely debated. This study addresses the problem of the origin of L. chagasi, its timing and demography with fast evolving genetic markers, a suite of Bayesian clustering algorithms and coalescent modelling. Here, using 14 microsatellite markers, 450 strains from the Leishmania donovani complex, we show that the vast majority of the Central and South American L. chagasi were nested within the Portuguese Leishmania infantum clade. Moreover, L. chagasi allelic richness was half that of their Old World counterparts. The bottleneck signature was estimated to be about 500 years old and the settlement of L. chagasi in the New World, probably via infected dogs, was accompanied by a thousand-fold population decrease. Visceral leishmaniasis, lethal if untreated, is therefore one more disease that the Conquistadores brought to the New World. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Fishing for anti-leishmania drugs: principles and problems.

    Science.gov (United States)

    Handman, Emanuela; Kedzierski, Lukasz; Uboldi, Alessandro D; Goding, James W

    2008-01-01

    To date, there are no vaccines against any of the major parasitic diseases including leishmaniasis, and chemotherapy is the main weapon in our arsenal. Current drugs are toxic and expensive, and are losing their effectiveness due to parasite resistance. The availability of the genome sequence of two species of Leishmania, Leishmania major and Leishmania infantum, as well as that of Trypanosoma brucei and Trypanosoma cruzi should provide a cornucopia of potential new drug targets. Their exploitation will require a multi-disciplinary approach that includes protein structure and function and high throughput screening of random and directed chemical libraries, followed by in vivo testing in animals and humans. We outline the opportunities that are made possible by recent technologies, and potential problems that need to be overcome.

  18. Toll-Like Receptors in Leishmania Infections: Guardians or Promoters?

    Directory of Open Access Journals (Sweden)

    Marilia S. Faria

    2012-01-01

    Full Text Available Protozoa of the genus Leishmania cause a wide variety of pathologies ranging from self-healing skin lesions to visceral damage, depending on the parasite species. The outcome of infection depends on the quality of the adaptive immune response, which is determined by parasite factors and the host genetic background. Innate responses, resulting in the generation of mediators with anti-leishmanial activity, contribute to parasite control and help the development of efficient adaptive responses. Among those, the potential contribution of members of the Toll-like receptors (TLRs family in the control of Leishmania infections started to be investigated about a decade ago. Although most studies appoint a protective role for TLRs, there is growing evidence that in some cases, TLRs facilitate infection. This review highlights recent advances in TLR function during Leishmania infections and discusses their potential role in restraining parasite growth versus yielding disease.

  19. Ecology of the leishmania species in the Guianan ecoregion complex.

    Science.gov (United States)

    Rotureau, Brice

    2006-01-01

    In the Guianan ecoregion complex, at least seven Leishmania species belonging to both the L. (Leishmania) Saf' janova, 1982 and L. (Viannia) Lainson and Shaw, 1987 sub-genera are causative agents of American visceral leishmaniasis, mucocutaneous leishmaniasis, and cutaneous leishmaniases, including localized and diffuse forms. They are mostly sylvatic species subjugated to their own specific Lutzomyia sand fly vectors and to particular wild mammalian reservoir hosts of the dense rain forest. Originally implicated strictly in wild zoonoses and developing in forested ecotopes, Leishmania show a particular adaptive plasticity to face environmental modifications following deforestation and anthropization. This review presents the different pathogenic complexes of these parasites, emphasizes their implication in human diseases, and considers the influence of humans on their ecology.

  20. Molecular crosstalks in Leishmania-sandfly-host relationships

    Directory of Open Access Journals (Sweden)

    Volf P.

    2008-09-01

    Full Text Available Sandflies (Diptera: Phlebotominae are vectors of Leishmania parasites, causative agents of important human and animal diseases with diverse manifestations. This review summarizes present knowledge about the vectorial part of Leishmania life cycle and parasite transmission to the vertebrate host. Particularly, it focuses on molecules that determine the establishment of parasite infection in sandfly midgut. It describes the concept of specific versus permissive sandfly vectors, explains the epidemiological consequences of broad susceptibility of permissive sandflies and demonstrates that genetic exchange may positively affect Leishmania fitness in the vector. Last but not least, the review describes recent knowledge about circulating antibodies produced by hosts in response to sandfly bites. Studies on specificity and kinetics of antibody response revealed that anti-saliva IgG could be used as a marker of host exposure to sandflies, i.e. as a useful tool for evaluation of vector control.

  1. Modulation of Dendritic Cell Function by Leishmania Parasites1

    Science.gov (United States)

    Soong, Lynn

    2009-01-01

    The interactions between Leishmania parasites and dendritic cells (DCs) are complex and involve paradoxical functions that can stimulate or halt T cell responses, leading to the control of infection or progression of disease. The magnitude and profile of DC activation vary greatly, depending upon the Leishmania species/strains, developmental stages, DC subsets, serum opsonization, and exogenous DC stimuli involved in the study. In general, the uptake of Leishmania parasites alone can trigger relatively weak and transient DC activation; however, the intracellular parasites (amastigotes) are capable of down-modulating LPS/IFN-γ-stimulated DC activation via multiple mechanisms. This review will highlight current data regarding the initial interaction of DC subsets with invading parasites, the alterations of DC signaling pathways and function by amastigotes, and the impact of DC functions on protective immunity and disease pathogenesis. Available information provides insight into the mechanisms by which DCs discriminate between the types of pathogens and regulate appropriate immune responses. PMID:18354154

  2. Modulation of dendritic cell function by Leishmania parasites.

    Science.gov (United States)

    Soong, Lynn

    2008-04-01

    The interactions between Leishmania parasites and dendritic cells (DCs) are complex and involve paradoxical functions that can stimulate or halt T cell responses, leading to the control of infection or progression of disease. The magnitude and profile of DC activation vary greatly, depending upon the Leishmania species/strains, developmental stages, DC subsets, serum opsonization, and exogenous DC stimuli involved in the study. In general, the uptake of Leishmania parasites alone can trigger relatively weak and transient DC activation; however, the intracellular parasites (amastigotes) are capable of down-modulating LPS/IFN-gamma-stimulated DC activation via multiple mechanisms. This review will highlight current data regarding the initial interaction of DC subsets with invading parasites, the alterations of DC signaling pathways and function by amastigotes, and the impact of DC functions on protective immunity and disease pathogenesis. Available information provides insight into the mechanisms by which DCs discriminate between the types of pathogens and regulate appropriate immune responses.

  3. Leishmania (infantum chagasi in canine urinary sediment

    Directory of Open Access Journals (Sweden)

    Ivete Lopes de Mendonça

    Full Text Available Canine visceral leishmaniasis (CVL is difficult to diagnosis, mainly due to the presence of asymptomatic animals, the diversity of clinical symptoms and the difficulty in obtaining diagnostic evidence of high sensitivity and specificity. The purpose of this study was to diagnose CVL in urinary sediment of 70 dogs of different breeds, sexes and ages from the veterinary hospital of the Federal University of Piauí and Zoonosis Control Center of Teresina, Brazil. The serological tests were TR DPP® for CVL and enzyme-linked immunosorbent assay (ELISA for CVL, parasitological exams of bone marrow and lymph nodes and urine sediment cultures. Leishmania was detected in the bone marrow and/or lymph node of 61.0% of the animals (43/70, and urine sediment culture was positive in 9.30% (4/43 of these animals. In the serological exams, 70.0% (49/70 were reactive using the DPP and 78.2% (55/70 were reactive using ELISA. The goal of this study was to diagnose the presence of L. (infantum chagasi in a culture of urinary sediment.

  4. Studies in vitro on infectivity and sensitivity to antileishmanial drugs in New World Leishmania species transfected with the green fluorescent protein [pIR3(-)-eGFP].

    Science.gov (United States)

    Palacios, Genesis; Parodi, Adriana; Upegui, Yulieth A; Montoya, Andres; Pulido, Sergio; Vélez, Iván D; Robledo, Sara M

    2017-11-01

    Current chemotherapeutic agents for leishmaniasis have several disadvantages interfering with the effective treatment and therefore more and better antileishmanial drugs are needed. Discovery of candidates for leishmaniasis treatment requires not only accurate and precise methodologies but also well-known biological system to measure infectivity of parasites and antileishmanial activity of the new compounds. Significant variation in the in vitro and in vivo infectivity and sensitivity to established and experimental drugs in Leishmania strains are reported. This work reports the in vitro biological behavior and antileishmanial drugs sensitivity of different green fluorescent protein transfectant Leishmanias strains. The in vitro growth kinetic and infectivity to U937 cells vary slightly in the Leishmania transfectant strains in comparison with their correspondant wild-type. However, the insertion of the pIR3(-)-eGFP may affect the sensitivity of the parasites to meglumine antimoniate (MA) and miltefosine but not to amphotericin B (AMB) and pentamidine isethionate. In consequence, AMB or pentamidine isethionate but not MA or miltefosine should be used as antileishmanial control drugs during in vitro assays of antileishmanial activity. Furthermore, is recommended to test compounds against more than one Leishmania strain in order to verify that the antileihmanial activity of these compound is similar among species.

  5. Intranasal vaccination with leishmanial antigens protects golden hamsters (Mesocricetus auratus) against Leishmania (Viannia) Braziliensis infection.

    Science.gov (United States)

    da Silva-Couto, Luzinei; Ribeiro-Romão, Raquel Peralva; Saavedra, Andrea Franco; da Silva Costa Souza, Beatriz Lilian; Moreira, Otacílio Cruz; Gomes-Silva, Adriano; Rossi-Bergmann, Bartira; Da-Cruz, Alda Maria; Pinto, Eduardo Fonseca

    2015-01-01

    Previous results have shown that oral and intranasal administration of particulate Leishmania (Leishmania) amazonensis antigens (LaAg) partially protects mice against L. amazonensis infection. However, vaccination studies on species of the subgenus Viannia, the main causative agent of cutaneous and mucosal leishmaniasis in the Americas, have been hampered by the lack of easy-to-handle bio-models that accurately mimic the human disease. Recently, we demonstrated that the golden hamster is an appropriate model for studying the immunopathogenesis of cutaneous leishmaniasis caused by L. (Viannia) braziliensis. Using the golden hamster model, our current study investigated whether the protective effect of intranasal immunisation with LaAg can be extended to L. braziliensis infection. Golden hamsters vaccinated with either two intranasal (IN) doses of LaAg (10 µg) or two intramuscular doses of LaAg (20 µg) were challenged 2 weeks post-vaccination with L. braziliensis. The results showed that IN immunisation with LaAg significantly reduced lesion growth and parasitic load as well as serum IgG and IgG2 levels. At the experimental endpoint on day 114 post-infection, IN-immunised hamsters that were considered protected expressed IFN-γ and IL10 mRNA levels that returned to uninfected skin levels. In contrast to the nasal route, intramuscular (IM) immunisation failed to provide protection. These results demonstrate for the first time that the nasal route of immunisation can induce cross protection against L. braziliensis infection.

  6. Vaccination with Leishmania histone H1-pulsed dendritic cells confers protection in murine visceral leishmaniasis.

    Science.gov (United States)

    Agallou, Maria; Smirlis, Despina; Soteriadou, Ketty P; Karagouni, Evdokia

    2012-07-20

    Visceral leishmaniasis is the most severe form of leishmaniases affecting millions of people worldwide often resulting in death despite optimal therapy. Thus, there is an urgent need for the development of effective anti-infective vaccine(s). In the present study, we evaluated the prophylactic value of bone marrow-derived dendritic cells (BM-DCs) pulsed with the Leishmania (L.) infantum histone H1. We developed fully mature BM-DCs characterized by enhanced capacity of IL-12 production after ex vivo pulsing with GST-LeishH1. Intravenous administration of these BM-DCs in naive BALB/c mice resulted in antigen-specific spleenocyte proliferation and IgG1 isotype antibody production and conferred protection against experimental challenge with L. infantum independently of CpG oligonucleotides (ODNs) co-administration. Protection was associated with a pronounced enhancement of parasite-specific IFNγ-producing cells and reduction of cells producing IL-10, whereas IL-4 production was comparable in protected and non-protected mice. The polarization of immune responses to Th1 type was further confirmed by the elevation of parasite-specific IgG2a/IgG1 ratio in protected mice. The above data indicate the immunostimulatory capacity of Leishmania histone H1 and further support its exploitation as a candidate protein for vaccine development against leishmaniasis. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Propolis reduces Leishmania amazonensis-induced inflammation in the liver of BALB/c mice.

    Science.gov (United States)

    da Silva, Suelen S; Mizokami, Sandra S; Fanti, Jacqueline R; Miranda, Milena M; Kawakami, Natalia Y; Teixeira, Fernanda Humel; Araújo, Eduardo J A; Panis, Carolina; Watanabe, Maria A E; Sforcin, José M; Pavanelli, Wander R; Verri, Waldiceu A; Felipe, Ionice; Conchon-Costa, Ivete

    2016-04-01

    Experimental models of mouse paw infection with L. amazonensis show an induction of a strong inflammatory response in the skin, and parasitic migration may occur to secondary organs with consequent tissue injury. There are few studies focusing on the resolution of damage in secondary organs caused by Leishmania species-related cutaneous leishmaniasis. We investigated the propolis treatment effect on liver inflammation induced by Leishmania amazonensis infection in the mouse paw. BALB/c mice were infected in the hind paw with L. amazonensis (10(7)) promastigote forms. After 15 days, animals were treated daily with propolis (5 mg/kg), Glucantime (10 mg/kg), or with propolis plus Glucantime combined. After 60 days, mice were euthanized and livers were collected for inflammatory process analysis. Liver microscopic analysis showed that propolis reduced the inflammatory process compared to untreated infected control. There was a decrease of liver myeloperoxidase and N-acetyl-β-glucosaminidase activity levels, collagen fiber deposition, pro-inflammatory cytokine production, and plasma aspartate transaminase and alanine transaminase levels. Furthermore, propolis treatment enhanced anti-inflammatory cytokine levels and reversed hepatosplenomegaly. Our data demonstrated that daily low doses of Brazilian propolis reduced the secondary chronic inflammatory process in the liver caused by L. amazonensis subcutaneous infection in a susceptible mice strain.

  8. F1 Domain of the Leishmania (Leishmania) donovani Nucleoside Hydrolase Promotes a Th1 Response in Leishmania (Leishmania) infantum Cured Patients and in Asymptomatic Individuals Living in an Endemic Area of Leishmaniasis

    OpenAIRE

    Carrillo, Eugenia; Fernandez, Laura; Ibarra-Meneses, Ana Victoria; Santos, Micheli L. B.; Nico, Dirlei; de Luca, Paula M.; Correa, Cristiane Bani; de Almeida, Roque Pacheco; Moreno, Javier; Palatnik-de-Sousa, Clarisa B.

    2017-01-01

    The Leishmania (Leishmania) donovani nucleoside hydrolase NH36 is the main antigen of the Leishmune® vaccine and one of the promising candidates for vaccination against visceral leishmaniasis. The antigenicity of the N-terminal (F1), the central (F2), or the C-terminal recombinant domain (F3) of NH36 was evaluated using peripheral blood mononuclear cells (PBMC) from individuals infected with L. (L.) infantum from an endemic area of visceral leishmaniasis of Spain. Both NH36 and F1 domains sig...

  9. Further support for a palaearctic origin of Leishmania

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    Sara F Kerr

    2000-08-01

    Full Text Available The fossil record and systematics of murid rodents, reservoirs of zoonotic cutaneous leishmaniasis in the Palaearctic, Oriental, African, Nearctic and Neotropical, strongly support a Palaearctic origin of Leishmania. The fossil record and systematics of phlebotomine sand flies reinforce this idea. Interpretations of molecular data that place the origin of Leishmania in the Neotropical are inconsistent with the natural histories of reservoirs and vectors. The evolutionary pattern of New World rats (Sigmodontinae indicates that they may be the most important reservoirs of zoonotic cutaneous leishmaniasis throughout their range.

  10. The past, present, and future of Leishmania genomics and transcriptomics

    Science.gov (United States)

    Cantacessi, Cinzia; Dantas-Torres, Filipe; Nolan, Matthew J.; Otranto, Domenico

    2015-01-01

    It has been nearly 10 years since the completion of the first entire genome sequence of a Leishmania parasite. Genomic and transcriptomic analyses have advanced our understanding of the biology of Leishmania, and shed new light on the complex interactions occurring within the parasite–host–vector triangle. Here, we review these advances and examine potential avenues for translation of these discoveries into treatment and control programs. In addition, we argue for a strong need to explore how disease in dogs relates to that in humans, and how an improved understanding in line with the ‘One Health’ concept may open new avenues for the control of these devastating diseases. PMID:25638444

  11. Prevalence and risk factors associated with Leishmania infection in Trang Province, southern Thailand.

    Science.gov (United States)

    Manomat, Jipada; Leelayoova, Saovanee; Bualert, Lertwut; Tan-Ariya, Peerapan; Siripattanapipong, Suradej; Mungthin, Mathirut; Naaglor, Tawee; Piyaraj, Phunlerd

    2017-11-01

    Autochthonous cutaneous and visceral leishmaniasis (VL) caused by Leishmania martiniquensis and Leishmania siamensis have been considered emerging infectious diseases in Thailand. The disease burden is significantly underestimated, especially the prevalence of Leishmania infection among HIV-positive patients. A cross-sectional study was conducted to determine the prevalence and risk factors associated with Leishmania infection among patients with HIV/AIDS living in Trang province, southern Thailand, between 2015 and 2016. Antibodies against Leishmania infection were assayed using the direct agglutination test (DAT). DNA of Leishmania was detected by ITS1-PCR using the buffy coat. Species of Leishmania were also identified. Of 724 participants, the prevalence of Leishmania infection was 25.1% (182/724) using either DAT or PCR assays. Seroprevalence of Leishmania infection was 18.5% (134/724), while Leishmania DNA detected by the PCR method was 8.4% (61/724). Of these, 24.9% (180/724) were asymptomatic, whereas 0.3% (2/724) were symptomatic VL and VL/CL (cutaneous leishmaniasis). At least five species were identified: L. siamensis, L. martiniquensis, L. donovani complex, L. lainsoni, and L. major. Multivariate analysis showed that CD4+ levels Leishmania infection. Those who were PCR positive for Leishmania DNA were significantly associated with a detectable viral load, whereas non-injection drug use (NIDU) and CD4+ levels Leishmania seropositivity. A magnitude of the prevalence of underreporting Leishmania infection among Thai patients with HIV was revealed in this study. Effective public health policy to prevent and control disease transmission is urgently needed.

  12. [Leishmania (leishmania) mexicana in the village of San Matias, municipality of Gomez Plata, North West of Antioquia, Colombia].

    Science.gov (United States)

    Sierra, Diana; Ochoa, Marcela; Calle, José Ignacio; García, Gisela; Colorado, Diana; Vélez, Iván Darío

    2006-10-01

    Leishmaniasis is found in natural foci of infection where both sand fly vectors and mammalian reservoirs of Leishmania are present. To report for the first time the presence of Leishmania (Leishmania) mexicana Biagi, 1953, in the village of San Matías, municipality of Gomez Plata, Department of Antioquia. The parasite was isolated from a patient with localized cutaneous leishmaniasis and was identified by the immunofluorescence technique using specific monoclonal antibodies against L. mexicana species and isoenzyme electrophoresis. The isoenzymatic profiles of the reference strains L. (L.) mexicana (MNCY/BZ/62/M379) and L. (L.) mexicana (MHOM/BE/82/BEL21) were similar to that of the isolate recovered from the patient, allowing us to classify it as L. (L.) mexicana.

  13. Correlation of meta 1 expression with culture stage, cell morphology and infectivity in Leishmania (Leishmania amazonensis promastigotes

    Directory of Open Access Journals (Sweden)

    Marcos Gonzaga dos Santos

    2011-03-01

    Full Text Available The parasitic protozoan Leishmania (Leishmania amazonensis alternates between mammalian and insect hosts. In the insect host, the parasites proliferate as procyclic promastigotes andthen differentiate into metacyclic infective forms. The meta 1 gene is preferentially expressed during metacyclogenesis. Meta 1 expression profile determination along parasite growth curves revealed that the meta 1 mRNA level peaked at the early stationary phase then decreased to an intermediate level. No correlation was observed between meta 1 expression and infectivity. Conversely, infectivity correlated with the increase of apoptotic cells in the late stationary phase.

  14. The presence of Tregs does not preclude immunity to reinfection with Leishmania braziliensis.

    Science.gov (United States)

    C Falcão, Sarah; de Moura, Tatiana R; Clarêncio, Jorge; Brodskyn, Cláudia; Barral, Aldina; de Oliveira, Camila I

    2012-07-01

    Leishmania spp. cause a broad spectrum of diseases collectively known as leishmaniasis. Leishmania braziliensis is the main etiological agent of American cutaneous leishmaniasis and mucocutaneous leishmaniasis. During experimental infection with L. braziliensis, BALB/c mice develop an adaptive immune response that is associated with lesion healing and, in parallel, parasite persistence within draining lymph nodes (dLNs). In the Leishmania major model of cutaneous leishmaniasis, regulatory T cells (Tregs) play an important role in immune regulation, preventing pathological immune responses but at the same time precluding sterile cure. In this study we investigated the role of Tregs during experimental infection with L. braziliensis. CD4(+)CD25(+) T cells were detected throughout the duration of clinical disease both at the ear and in dLNs of infected mice. These cells expressed Treg markers such as glucocorticoid-induced TNF-receptor-related protein (GITR), the α chain of the αεβ7 integrin (CD103), and the forkhead/winged helix transcription factor, Foxp3, and were able to suppress the proliferation of CD4(+)CD25(-) cells. Importantly, a high frequency of Foxp3(+) cells accumulated at the site of infection and in dLNs. We next investigated the outcome of a reinfection with L. braziliensis in terms of Treg distribution and disease reactivation. Interestingly, a secondary inoculation with L. braziliensis did not preclude an efficient recall response to L. braziliensis at a distal site, despite the presence of Tregs. Within dLNs, reinfection did not promote parasite dissemination or a differential recruitment of either CD4(+)CD25(+)Foxp3(+) or CD4(+)IL-10(+) T cells. On the contrary, parasites were mainly detected in the LN draining the primary infection site where a high frequency of CD4(+)IFN-γ(+) T cells was also present. Collectively these data show that during experimental infection, Tregs are present in healed mice but this population does not compromise an

  15. A Poly(Lactic-co-Glycolic) Acid Nanovaccine Based on Chimeric Peptides from Different Leishmania infantum Proteins Induces Dendritic Cells Maturation and Promotes Peptide-Specific IFNγ-Producing CD8+ T Cells Essential for the Protection against Experimental Visceral Leishmaniasis

    Science.gov (United States)

    Athanasiou, Evita; Agallou, Maria; Tastsoglou, Spyros; Kammona, Olga; Hatzigeorgiou, Artemis; Kiparissides, Costas; Karagouni, Evdokia

    2017-01-01

    Visceral leishmaniasis, caused by Leishmania (L.) donovani and L. infantum protozoan parasites, can provoke overwhelming and protracted epidemics, with high case-fatality rates. An effective vaccine against the disease must rely on the generation of a strong and long-lasting T cell immunity, mediated by CD4+ TH1 and CD8+ T cells. Multi-epitope peptide-based vaccine development is manifesting as the new era of vaccination strategies against Leishmania infection. In this study, we designed chimeric peptides containing HLA-restricted epitopes from three immunogenic L. infantum proteins (cysteine peptidase A, histone H1, and kinetoplastid membrane protein 11), in order to be encapsulated in poly(lactic-co-glycolic) acid nanoparticles with or without the adjuvant monophosphoryl lipid A (MPLA) or surface modification with an octapeptide targeting the tumor necrosis factor receptor II. We aimed to construct differentially functionalized peptide-based nanovaccine candidates and investigate their capacity to stimulate the immunomodulatory properties of dendritic cells (DCs), which are critical regulators of adaptive immunity generated upon vaccination. According to our results, DCs stimulation with the peptide-based nanovaccine candidates with MPLA incorporation or surface modification induced an enhanced maturation profile with prominent IL-12 production, promoting allogeneic T cell proliferation and intracellular production of IFNγ by CD4+ and CD8+ T cell subsets. In addition, DCs stimulated with the peptide-based nanovaccine candidate with MPLA incorporation exhibited a robust transcriptional activation, characterized by upregulated genes indicative of vaccine-driven DCs differentiation toward type 1 phenotype. Immunization of HLA A2.1 transgenic mice with this peptide-based nanovaccine candidate induced peptide-specific IFNγ-producing CD8+ T cells and conferred significant protection against L. infantum infection. Concluding, our findings supported that encapsulation

  16. A Poly(Lactic-co-Glycolic) Acid Nanovaccine Based on Chimeric Peptides from Different Leishmania infantum Proteins Induces Dendritic Cells Maturation and Promotes Peptide-Specific IFNγ-Producing CD8(+) T Cells Essential for the Protection against Experimental Visceral Leishmaniasis.

    Science.gov (United States)

    Athanasiou, Evita; Agallou, Maria; Tastsoglou, Spyros; Kammona, Olga; Hatzigeorgiou, Artemis; Kiparissides, Costas; Karagouni, Evdokia

    2017-01-01

    Visceral leishmaniasis, caused by Leishmania (L.) donovani and L. infantum protozoan parasites, can provoke overwhelming and protracted epidemics, with high case-fatality rates. An effective vaccine against the disease must rely on the generation of a strong and long-lasting T cell immunity, mediated by CD4(+) TH1 and CD8(+) T cells. Multi-epitope peptide-based vaccine development is manifesting as the new era of vaccination strategies against Leishmania infection. In this study, we designed chimeric peptides containing HLA-restricted epitopes from three immunogenic L. infantum proteins (cysteine peptidase A, histone H1, and kinetoplastid membrane protein 11), in order to be encapsulated in poly(lactic-co-glycolic) acid nanoparticles with or without the adjuvant monophosphoryl lipid A (MPLA) or surface modification with an octapeptide targeting the tumor necrosis factor receptor II. We aimed to construct differentially functionalized peptide-based nanovaccine candidates and investigate their capacity to stimulate the immunomodulatory properties of dendritic cells (DCs), which are critical regulators of adaptive immunity generated upon vaccination. According to our results, DCs stimulation with the peptide-based nanovaccine candidates with MPLA incorporation or surface modification induced an enhanced maturation profile with prominent IL-12 production, promoting allogeneic T cell proliferation and intracellular production of IFNγ by CD4(+) and CD8(+) T cell subsets. In addition, DCs stimulated with the peptide-based nanovaccine candidate with MPLA incorporation exhibited a robust transcriptional activation, characterized by upregulated genes indicative of vaccine-driven DCs differentiation toward type 1 phenotype. Immunization of HLA A2.1 transgenic mice with this peptide-based nanovaccine candidate induced peptide-specific IFNγ-producing CD8(+) T cells and conferred significant protection against L. infantum infection. Concluding, our findings supported that

  17. A Poly(Lactic-co-Glycolic Acid Nanovaccine Based on Chimeric Peptides from Different Leishmania infantum Proteins Induces Dendritic Cells Maturation and Promotes Peptide-Specific IFNγ-Producing CD8+ T Cells Essential for the Protection against Experimental Visceral Leishmaniasis

    Directory of Open Access Journals (Sweden)

    Evita Athanasiou

    2017-06-01

    Full Text Available Visceral leishmaniasis, caused by Leishmania (L. donovani and L. infantum protozoan parasites, can provoke overwhelming and protracted epidemics, with high case-fatality rates. An effective vaccine against the disease must rely on the generation of a strong and long-lasting T cell immunity, mediated by CD4+ TH1 and CD8+ T cells. Multi-epitope peptide-based vaccine development is manifesting as the new era of vaccination strategies against Leishmania infection. In this study, we designed chimeric peptides containing HLA-restricted epitopes from three immunogenic L. infantum proteins (cysteine peptidase A, histone H1, and kinetoplastid membrane protein 11, in order to be encapsulated in poly(lactic-co-glycolic acid nanoparticles with or without the adjuvant monophosphoryl lipid A (MPLA or surface modification with an octapeptide targeting the tumor necrosis factor receptor II. We aimed to construct differentially functionalized peptide-based nanovaccine candidates and investigate their capacity to stimulate the immunomodulatory properties of dendritic cells (DCs, which are critical regulators of adaptive immunity generated upon vaccination. According to our results, DCs stimulation with the peptide-based nanovaccine candidates with MPLA incorporation or surface modification induced an enhanced maturation profile with prominent IL-12 production, promoting allogeneic T cell proliferation and intracellular production of IFNγ by CD4+ and CD8+ T cell subsets. In addition, DCs stimulated with the peptide-based nanovaccine candidate with MPLA incorporation exhibited a robust transcriptional activation, characterized by upregulated genes indicative of vaccine-driven DCs differentiation toward type 1 phenotype. Immunization of HLA A2.1 transgenic mice with this peptide-based nanovaccine candidate induced peptide-specific IFNγ-producing CD8+ T cells and conferred significant protection against L. infantum infection. Concluding, our findings supported that

  18. [Reaction of Leishmania (Leishmania) mexicana antigens by sera of patients with cutaneous leishmaniasis from Sinaloa, Mexico].

    Science.gov (United States)

    Salazar-Mejía, Patricia Guadalupe; Tejeda-Aguirre, Celia Rosa; López-Moreno, Héctor Samuel

    2010-01-01

    To detect Leishmania mexicana antigens reacting with sera of patients with cutaneous leishmaniasis (CL). A crude extract of L. mexicana was used as antigen for 2-D Western blot using sera from 5 patients with CL and controls from Sinaloa, Mexico during 2008. Five antigens were detected in the five infected patients analyzed; their molecular weights and isoelectric points were: 26 kDa (pI 7.8), 27 kDa (pI 8.1), 28 kDa (pI 8.6), 29 kDa (pI 8.5) and 31 kDa (pI 9.0). New potentially immunodominant L. mexicana antigens were detected, suggesting that this parasite could be the species responsible for human infection in Sinaloa.

  19. Murine immune response induced by Leishmania major during the implantation of paraffin tablets

    Science.gov (United States)

    Reis, Maria Letícia Costa; Ferreira, Vanessa Martins; Zhang, Xia; Gonçalves, Ricardo; Vieira, Leda Quércia; Tafuri, Washington Luiz; Mosser, David M.

    2011-01-01

    We carried out a model of chronic inflammation using a subcutaneous paraffin tablet in mice experimentally infected with Leishmania major. It was previously reported that the parasite load following paraffin implantation occurred at a peak of 21 days in both BALB/c and C57BL/6 mice. At the present study, we have investigated what cytokines and chemokines are directly related to the parasite load in C57BL/6 mice. All mice were divided in four groups: mice implanted with paraffin tablets; mice experimentally infected with L. major; mice implanted with paraffin tablets and experimentally infected with L. major; and mice submitted only to the surgery were used for the Real-Time Polymerase Chain Reaction (RT-PCR) controls. Fragments of skin tissue and the tissue surrounding the paraffin tablets (inflammatory capsule) were collected for histopathology and RT-PCR studies. By 21 days, a diffuse chronic inflammatory reaction was mainly observed in the deep dermis where macrophages parasitized with Leishmania amastigotes were also found. RT-PCR analysis has shown that BALB/c mice showed strong IL-4 and IL-10 mRNA expression than controls with very little expression of IFN-γ. In contrast, both IFN-γ and IL-10 mRNA was found in higher levels in C57BL/6 animals. Moreover, in C57BL/6 mice the expression of chemokines mRNA of CCL3/MIP-1α was more highly expressed than CCL2/MCP-1. We conclude that the Th1 immune response C57BL/6 did not change to a Th2 response, even though C57BL/6 animals presented higher parasitism than BALB/c mice 21 days after infection and paraffin implantation. PMID:20857143

  20. Vaccination using live attenuated Leishmania donovani centrin deleted parasites induces protection in dogs against Leishmania infantum.

    Science.gov (United States)

    Fiuza, Jacqueline Araújo; Gannavaram, Sreenivas; Santiago, Helton da Costa; Selvapandiyan, Angamuthu; Souza, Daniel Menezes; Passos, Lívia Silva Araújo; de Mendonça, Ludmila Zanandreis; Lemos-Giunchetti, Denise da Silveira; Ricci, Natasha Delaqua; Bartholomeu, Daniella Castanheira; Giunchetti, Rodolfo Cordeiro; Bueno, Lilian Lacerda; Correa-Oliveira, Rodrigo; Nakhasi, Hira L; Fujiwara, Ricardo Toshio

    2015-01-03

    Live attenuated Leishmania donovani parasites such as LdCen(-/-) have been shown elicit protective immunity against leishmanial infection in mice and hamster models. Previously, we have reported on the induction of strong immunogenicity in dogs upon vaccination with LdCen(-/-) including an increase in immunoglobulin isotypes, higher lymphoproliferative response, higher frequencies of activated CD4(+) and CD8(+) T cells, IFN-γ production by CD8(+) T cells, increased secretion of TNF-α and IL-12/IL-23p40 and, finally, decreased secretion of IL-4. To further explore the potential of LdCen(-/-) parasites as vaccine candidates, we performed a 24-month follow up of LdCen(-/-) immunized dogs after challenge with virulent Leishmania infantum, aiming determination of parasite burden by qPCR, antibody production (ELISA) and cellular responses (T cell activation and cytokine production) by flow cytometry and sandwich ELISA. Our data demonstrated that vaccination with a single dose of LdCen(-/-) (without any adjuvant) resulted in the reduction of up to 87.3% of parasite burden after 18 months of virulent challenge. These results are comparable to those obtained with commercially available vaccine in Brazil (Leishmune(®)). The protection was associated with antibody production and CD4(+) and CD8(+) proliferative responses, as well as T cell activation and significantly higher production of IFN-γ, IL-12/IL-23p40 and TNF-α, which was comparable to responses induced by immunization with Leishmune(®), with significant differences when compared to control animals (Placebo). Moreover, only animals immunized with LdCen(-/-) expressed lower levels of IL-4 when compared to animals vaccinated either with Leishmune(®) or PBS. Our results support further studies aiming to demonstrate the potential of genetically modified live attenuated L. donovani vaccine to control L. infantum transmission in endemic areas for CVL. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. The Genetic Relationship between Leishmania aethiopica and Leishmania tropica Revealed by Comparing Microsatellite Profiles.

    Science.gov (United States)

    Krayter, Lena; Schnur, Lionel F; Schönian, Gabriele

    2015-01-01

    Leishmania (Leishmania) aethiopica and L. (L.) tropica cause cutaneous leishmaniases and appear to be related. L. aethiopica is geographically restricted to Ethiopia and Kenya; L. tropica is widely dispersed from the Eastern Mediterranean, through the Middle East into eastern India and in north, east and south Africa. Their phylogenetic inter-relationship is only partially revealed. Some studies indicate a close relationship. Here, eight strains of L. aethiopica were characterized genetically and compared with 156 strains of L. tropica from most of the latter species' geographical range to discern the closeness. Twelve unlinked microsatellite markers previously used to genotype strains of L. tropica were successfully applied to the eight strains of L. aethiopica and their microsatellite profiles were compared to those of 156 strains of L. tropica from various geographical locations that were isolated from human cases of cutaneous and visceral leishmaniasis, hyraxes and sand fly vectors. All the microsatellite profiles were subjected to various analytical algorithms: Bayesian statistics, distance-based and factorial correspondence analysis, revealing: (i) the species L. aethiopica, though geographically restricted, is genetically very heterogeneous; (ii) the strains of L. aethiopica formed a distinct genetic cluster; and (iii) strains of L. aethiopica are closely related to strains of L. tropica and more so to the African ones, although, by factorial correspondence analysis, clearly separate from them. The successful application of the 12 microsatellite markers, originally considered species-specific for the species L. tropica, to strains of L. aethiopica confirmed the close relationship between these two species. The Bayesian and distance-based methods clustered the strains of L. aethiopica among African strains of L. tropica, while the factorial correspondence analysis indicated a clear separation between the two species. There was no correlation between

  2. Photoacoustic monitoring of life cycles of Leishmania Mexicana

    Science.gov (United States)

    Arguello, C.; Acosta-Avalos, D.; Alvarado-Gil, J. J.; Vargas, H.

    1999-03-01

    Photoacoustic spectroscopy is used to monitor in situ, the difference between the two forms of the protozoan Leishmania Mexicana. Differences are the result of changes in the respiratory chain and could be attributed, according to our results, to the presence of cytochrome b in promastigotes and cytochrome c in amastigotes.

  3. Sand fly evolution and its relationship to Leishmania transmission

    Directory of Open Access Journals (Sweden)

    PD Ready

    2000-08-01

    Full Text Available The evolutionary relationships of sand flies and Leishmania are discussed in this report, which draws distinctions between co-association, co-evolution and co-speciation (or co-cladogenesis. Examples focus on Phlebotomus vectors of Le. infantum and Le. major in the Mediterranean subregion.

  4. Vectorborne Transmission of Leishmania infantum from Hounds, United States

    OpenAIRE

    Schaut, Robert G.; Robles-Murguia, Maricela; Juelsgaard, Rachel; Esch, Kevin J.; Bartholomay, Lyric C.; Ramalho-Ortigao, Marcelo; Petersen, Christine A.

    2015-01-01

    Leishmaniasis is a zoonotic disease caused by predominantly vectorborne Leishmania spp. In the United States, canine visceral leishmaniasis is common among hounds, and L. infantum vertical transmission among hounds has been confirmed. We found that L. infantum from hounds remains infective in sandflies, underscoring the risk for human exposure by vectorborne transmission.

  5. Investigation of Leishmania infantum seropositivity in HIV/AIDS patients

    NARCIS (Netherlands)

    Ozkan, Ayşegül Taylan; Yalçinkaya, Tülay; Kiliç, Selçuk; Babür, Cahit; Schallig, Henk D. F. H.

    2008-01-01

    In recent years an increase in the rate of detection of HIV and Leishmania co-infections has been reported from many countries especially countries in Southern Europe. Visceral leishmaniasis (VL) is sporadically detected in some parts of Turkey. Although the natural transmission is via sandfly

  6. Manifestations of paediatric Leishmania infantum infections in Malta

    OpenAIRE

    Pace, David; Williams, Thomas N.; Grochowska, Alicja; Betts, Alexandra; Attard-Montalto, Simon; Boffa, Michael J.; Vella, Cecil

    2011-01-01

    Summary Leishmania infantum is endemic in the Maltese archipelago, a group of islands in the Mediterranean which are visited frequently by tourists from Northern European countries. The burden of leishmaniasis is highest in children who may present with cutaneous or visceral manifestations. We describe systematically the manifestations, diagnosis and management of leishmaniasis in children

  7. Vaccinations with live-attenuated Leishmania major promastigotes ...

    African Journals Online (AJOL)

    Background: Currently there is no vaccine available in use against any form of leishmaniases worldwide. Objective: To assess potential of a live-attenuated Leishmania major promastigates, for protection against a challenge infection with L. major in BALB/c mice. Design. A laboratory based study. Setting: Study was carried ...

  8. Studies on the interaction of Schistosoma mansoni and Leishmania ...

    African Journals Online (AJOL)

    Schistosoma mansoni and Leishmania major are important tropical human parasites. It is crucial to know the effect of the two infecting man concurrently. Two groups of BALB/c mice were infected with each of the parasites separately; another group was co-infected with both parasites and there was a naïve control. Draining ...

  9. Generation of species-specific DNA probes for Leishmania aethiopica

    NARCIS (Netherlands)

    Laskay, T.; Kiessling, R.; Rinke deWit, T. F.; Wirth, D. F.

    1991-01-01

    We report here the cloning of kinetoplast DNA (kDNA) sequences from Leishmania aethiopica in order to develop a specific and sensitive method for the identification of the parasite. Analysis of the cloned kDNA sequences showed different taxonomic specificities demonstrating sequence diversity within

  10. Leishmania amastigotes in neoplastic cells of 3 nonhistiocytic canine tumors.

    Science.gov (United States)

    Ferro, S; Palmieri, C; Cavicchioli, L; De Zan, G; Aresu, L; Benali, S L

    2013-09-01

    Concurrent leishmaniasis and neoplasia has been reported in dogs. This study describes the presence of the protozoa within the cytoplasm of neoplastic cells in 3 different types of tumors. Leishmania amastigotes were detected by light and transmission electron microscopy and immunohistochemistry in a fibrosarcoma, a T-cell lymphoma, and an adrenocortical adenoma.

  11. Vaccination of BALB/c mice with Leishmania donovani derived ...

    African Journals Online (AJOL)

    Objective: To determine whether Leishmania donovani-derived lipophosphoglycan (LPG) can confer cross-protection to L. major in susceptible BALB/c mouse model. BALB/mice were immunized with a total dose of 30µg of LPG plus 150µl of mycobacterium bovis Bacille Calmette guerin (BCG) and later challenged with ...

  12. Leishmania amazonensis Engages CD36 to Drive Parasitophorous Vacuole Maturation.

    Directory of Open Access Journals (Sweden)

    Kendi Okuda

    2016-06-01

    Full Text Available Leishmania amastigotes manipulate the activity of macrophages to favor their own success. However, very little is known about the role of innate recognition and signaling triggered by amastigotes in this host-parasite interaction. In this work we developed a new infection model in adult Drosophila to take advantage of its superior genetic resources to identify novel host factors limiting Leishmania amazonensis infection. The model is based on the capacity of macrophage-like cells, plasmatocytes, to phagocytose and control the proliferation of parasites injected into adult flies. Using this model, we screened a collection of RNAi-expressing flies for anti-Leishmania defense factors. Notably, we found three CD36-like scavenger receptors that were important for defending against Leishmania infection. Mechanistic studies in mouse macrophages showed that CD36 accumulates specifically at sites where the parasite contacts the parasitophorous vacuole membrane. Furthermore, CD36-deficient macrophages were defective in the formation of the large parasitophorous vacuole typical of L. amazonensis infection, a phenotype caused by inefficient fusion with late endosomes and/or lysosomes. These data identify an unprecedented role for CD36 in the biogenesis of the parasitophorous vacuole and further highlight the utility of Drosophila as a model system for dissecting innate immune responses to infection.

  13. Studies on the interaction of Schistosoma mansoni and Leishmania ...

    African Journals Online (AJOL)

    kemrilib

    Introduction. Schistosomiasis and leishmaniasis are two parasitic diseases associated with great human suffering in the endemic areas. The two diseases are widespread and double infection is not an uncommon feature [1, 2]. Interestingly, some infections with Schistosoma (a parasitic helminth) and Leishmania (a parasitic.

  14. Studies on Stibanate unresponsive isolates of Leishmania donovani

    Indian Academy of Sciences (India)

    Visceral leishmaniasis, also known as kala-azar (KA) is generally caused by Leishmania donovani. Organic pentavalent antimonials (SbV) is the first line of treatment for KA. However, the number of KA patients unresponsive to treatment with Sb(V) is steadily increasing in India and elsewhere. The primary objective of this ...

  15. Isolation of Leishmania tropica from an Ethiopian cutaneous leishmaniasis patient

    NARCIS (Netherlands)

    Hailu, Asrat; Di Muccio, Trentina; Abebe, Tamrat; Hunegnaw, Mesfin; Kager, Piet A.; Gramiccia, Marina

    2006-01-01

    Cutaneous leishmaniasis (CL) in the Old World is caused mainly by three species of Leishmania: L. major, L. tropica and L. aethiopica, and sporadically by L. infantum and L. donovani. In Ethiopia, zoonotic cutaneous leishmaniasis, caused by L. aethiopica, is a major public health problem affecting

  16. Studies on Stibanate unresponsive isolates of Leishmania donovani

    Indian Academy of Sciences (India)

    Unknown

    Visceral leishmaniasis, also known as kala-azar (KA) is generally caused by Leishmania donovani. Organic pentavalent antimonials (SbV) is the first line of treatment for KA. However, the number of KA patients unres- ponsive to treatment with Sb(V) is steadily increasing in India and elsewhere. The primary objective of this.

  17. Biosynthesis of silver nanoparticles by Leishmania tropica | Rahi ...

    African Journals Online (AJOL)

    A novel biosynthesis route for Silver Nanoparticles (Ag-NPs) was attempted in the present study using Leishmania tropica the causative agent of cutaneous leishmaniasis in different countries, particularly in Mediterranean region in Iraq. Silver nanoparticles were successfully synthesized from AgNO3 by reduction of ...

  18. Leishmania spp.: proficiency of drug-resistant parasites.

    Science.gov (United States)

    Natera, Sonimar; Machuca, Claudia; Padrón-Nieves, Maritza; Romero, Amarilis; Díaz, Emilia; Ponte-Sucre, Alicia

    2007-06-01

    Leishmaniasis is a disease caused by at least 17 different species of protozoan Leishmania parasites and currently affects around 12 million people living mostly in tropical and subtropical areas. Failure to treat leishmaniasis successfully is often due to drug resistance. However, there are no cellular and molecular markers of chemoresistance against leishmanicidal drugs and the only reliable method for monitoring resistance of individual isolates is the in vitro amastigote/macrophage model. It is thus necessary to find cellular and molecular markers that can be used systematically to identify the drug-resistant phenotype of the infecting parasites. Until now, whether drug resistance in Leishmania compromises parasite proficiency, e.g. in terms of infectivity or metabolism, has not been systematically evaluated. Therefore, here we examine whether the physiological changes expressed by drug-resistant Leishmania reflect a modification of parasite vitality in drug-resistant compared with drug-sensitive parasites. Finally, the clinical implications of drug resistance in Leishmania are also discussed.

  19. Serological and molecular survey of Leishmania parasites in apparently healthy dogs in the West Bank, Palestine

    Science.gov (United States)

    2012-01-01

    Background Canine visceral leishmaniasis (CVL) is caused by Leishmania infantum in all Mediterranean countries. The Leishmania parasite is transmitted by the bite of a corresponding sand fly vector and primarily maintained in nature by wild and domestic reservoirs, including dogs, foxes and jackals. Infected dogs are the primary reservoir host in endemic regions and are the most significant risk disposing humans to infection. The present study aimed at assessing the prevalence of infection with Leishmania and identification of Leishmania infantum in domestic dogs in the West Bank, Palestine. Methods The infection rate among domestic dogs collected from seven districts in the Palestinian West Bank was investigated by examination of parasites in culture from the buffy coat using serological and molecular methods; based on ELISA, internal transcribed spacer 1 (ITS1) and cysteine protease (CPB) PCR. Results Out of 215 dogs examined for Leishmania, 36 (16.7%) were positive in at least one method. Twenty three animals (11.5%) were positive for Leishmania DNA, whereas, ELISA and culture revealed 16 (7.5%), and 4 (1.5%) respectively. CPB-PCR on one of three culture-positive isolates revealed Leishmania infantum as the causative agent for Leishmania infection in dogs. Conclusions Our study showed that canine leishmania infection is prevalent with varying degrees in all the seven studied districts in Palestine despite the absence of human VL cases in 4 of these districts. The causative agent was confirmed to be Leishmania infantum. PMID:22937916

  20. Evaluation of recombinant Leishmania poly-protein plus GLA-SE vaccines against sand fly-transmitted Leishmania major in C57Bl/6 mice1

    Science.gov (United States)

    Peters, Nathan C.; Bertholet, Sylvie; Lawyer, Phillip G.; Charmoy, Melanie; Romano, Audrey; Ribeiro-Gomes, Flavia L.; Stamper, Lisa W.; Sacks, David L.

    2012-01-01

    Numerous experimental Leishmania vaccines have been developed to prevent the visceral and cutaneous forms of Leishmaniasis, which occur after exposure to the bite of an infected sand fly, yet only one is under evaluation in humans. KSAC and L110f, recombinant Leishmania poly-proteins delivered in a stable emulsion (SE) with the TLR 4 agonists monophosphoryl lipid A (MPL) or glucopyranosyl lipid A (GLA) have shown protection in animal models. KSAC+GLA-SE protected against cutaneous disease following sand fly transmission of L. major in susceptible BALB/c mice. Similar poly-protein adjuvant combinations are the vaccine candidates most likely to see clinical evaluation. We assessed immunity generated by KSAC or L110f vaccination with GLA-SE following challenge with L. major by needle or infected sand fly bite in resistant C57BL/6 mice. Poly-protein vaccinated mice had a 60-fold increase in CD4+IFN-γ+ T cell numbers versus control animals at 2 weeks post needle inoculation of L. major and this correlated with a 100-fold reduction in parasite load. Immunity did not, however, reach levels observed in mice with a healed primary infection. Following challenge by infected sand fly bite, poly-protein vaccinated animals had comparable parasite loads, greater numbers of neutrophils at the challenge site, and reduced CD4+ IFN-γ+:IL-17+ ratios versus non-vaccinated controls. In contrast, healed animals had significantly reduced parasite loads and higher CD4+ IFN-γ+:IL-17+ ratios. These observations demonstrate that vaccine-induced protection against needle challenge does not necessarily translate to protection following challenge by infected sand fly bite. PMID:23045616

  1. Immunity and immunosuppression in experimental visceral leishmaniasis

    OpenAIRE

    Goto H; Lindoso J.A.L.

    2004-01-01

    Leishmaniasis is a disease caused by protozoa of the genus Leishmania, and visceral leishmaniasis is a form in which the inner organs are affected. Since knowledge about immunity in experimental visceral leishmaniasis is poor, we present here a review on immunity and immunosuppression in experimental visceral leishmaniasis in mouse and hamster models. We show the complexity of the mechanisms involved and differences when compared with the cutaneous form of leishmaniasis. Resistance in viscera...

  2. Monitoring the response of patients with cutaneous leishmaniasis to treatment with pentamidine isethionate by quantitative real-time PCR, and identification of Leishmania parasites not responding to therapy.

    Science.gov (United States)

    Mans, D R A; Kent, A D; Hu, R V; Lai A Fat, E J; Schoone, G J; Adams, E R; Rood, E J; Alba, S; Sabajo, L O A; Lai A Fat, R F; de Vries, H J C; Schallig, H D F H

    2016-08-01

    Leishmania (Viannia) guyanensis is believed to be the principal cause of cutaneous leishmaniasis (CL) in Suriname. This disease is treated with pentamidine isethionate (PI), but treatment failure has increasingly been reported. To evaluate PI for its clinical efficacy, to compare parasite load, and to assess the possibility of treatment failure due to other infecting Leishmania species. Parasite load of patients with CL was determined in skin biopsies using real-time quantitative PCR before treatment and 6 and 12 weeks after treatment. Clinical responses were evaluated at week 12 and compared with parasite load. In parallel, molecular species differentiation was performed. L. (V.) guyanensis was the main infecting species in 129 of 143 patients (about 90%). PI treatment led to a significant decrease (P < 0.001) in parasite counts, and cured about 75% of these patients. Treatment failure was attributable to infections with Leishmania (Viannia) braziliensis, Leishmania (Leishmania) amazonensis and L. (V.) guyanensis (1/92, 1/92 and 22/92 evaluable cases, respectively). There was substantial agreement beyond chance between the parasite load at week 6 and the clinical outcome at week 12, as indicated by the κ value of 0.61. L. (V.) guyanensis is the main infecting species of CL in Suriname, followed by L. (V.) braziliensis and L. (L.) amazonensis. Furthermore, patient response to PI can be better anticipated based on the parasite load 6 weeks after the treatment rather than on parasite load before treatment. © 2015 The Authors Clinical and Experimental Dermatology published by John Wiley & Sons Ltd on behalf of British Association of Dermatologists, North American Clinical Dermatologic Society and St Johns Dermatological Society.

  3. Easy identification of leishmania species by mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Oussama Mouri

    2014-06-01

    Full Text Available BACKGROUND: Cutaneous leishmaniasis is caused by several Leishmania species that are associated with variable outcomes before and after therapy. Optimal treatment decision is based on an accurate identification of the infecting species but current methods to type Leishmania isolates are relatively complex and/or slow. Therefore, the initial treatment decision is generally presumptive, the infecting species being suspected on epidemiological and clinical grounds. A simple method to type cultured isolates would facilitate disease management. METHODOLOGY: We analyzed MALDI-TOF spectra of promastigote pellets from 46 strains cultured in monophasic medium, including 20 short-term cultured isolates from French travelers (19 with CL, 1 with VL. As per routine procedure, clinical isolates were analyzed in parallel with Multilocus Sequence Typing (MLST at the National Reference Center for Leishmania. PRINCIPAL FINDINGS: Automatic dendrogram analysis generated a classification of isolates consistent with reference determination of species based on MLST or hsp70 sequencing. A minute analysis of spectra based on a very simple, database-independent analysis of spectra based on the algorithm showed that the mutually exclusive presence of two pairs of peaks discriminated isolates considered by reference methods to belong either to the Viannia or Leishmania subgenus, and that within each subgenus presence or absence of a few peaks allowed discrimination to species complexes level. CONCLUSIONS/SIGNIFICANCE: Analysis of cultured Leishmania isolates using mass spectrometry allows a rapid and simple classification to the species complex level consistent with reference methods, a potentially useful method to guide treatment decision in patients with cutaneous leishmaniasis.

  4. Phylogenetic relationships of Leishmania species based on trypanosomatid barcode (SSU rDNA) and gGAPDH genes: Taxonomic revision of Leishmania (L.) infantum chagasi in South America.

    Science.gov (United States)

    Marcili, Arlei; Sperança, Marcia Ap; da Costa, Andrea P; Madeira, Maria de F; Soares, Herbert S; Sanches, Camila de O C C; Acosta, Igor da C L; Girotto, Aline; Minervino, Antonio H H; Horta, Maurício C; Shaw, Jeffrey J; Gennari, Solange M

    2014-07-01

    Phylogenetic studies on trypanosomatid barcode using V7V8 SSU rRNA and gGAPDH gene sequences have provided support for redefining some trypanosomatid species and positioning new isolates. The genus Leishmania is a slow evolving monophyletic group and including important human pathogens. The phylogenetic relationships of this genus have been determined by the natural history of its vertebrate hosts, vector specificity, clinical manifestations, geographical distribution and molecular approaches using different markers. Thus, in an attempt to better understand the phylogenetic relationships of Leishmania species, we performed phylogenetic analysis on trypanosomatid barcode using V7V8 SSU rRNA and gGAPDH gene sequences among a large number of Leishmania species and also several Brazilian visceral Leishmania infantum chagasi isolates obtained from dogs and humans. Our phylogenetic analysis strongly suggested that Leishmania hertigi and Leishmania equatoriensis should be taxonomically revised so as to include them in the genus Endotrypanum; and supported ancient divergence of Leishmania enriettii. This, together with recent data in the literature, throws light on the discussion about the evolutionary southern supercontinent hypothesis for the origin of Leishmania ssp. and validates L. infantum chagasi from Brazil, thus clearly differentiating it from L. infantum, for the first time. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

  5. IL-32gamma promotes the healing of murine cutaneous lesions caused by Leishmania braziliensis infection in contrast to Leishmania amazonensis

    NARCIS (Netherlands)

    Gomes, R.S.; Silva, M.V.T.; Santos, J.C. Dos; Silva, L.L. de Lima; Batista, A.C.; Machado, J.R.; Teixeira, M.M.; Dorta, M.L.; Oliveira, M.A. de; Dinarello, C.A.; Joosten, L.A.B.; Ribeiro-Dias, F.

    2017-01-01

    BACKGROUND: Interleukin 32 (IL-32) is a pro-inflammatory cytokine induced in patients with American tegumentary leishmaniasis (ATL) caused by Leishmania braziliensis. Here, we investigated whether IL-32 is also expressed in patient lesions caused by L. amazonensis. In addition, we evaluated

  6. Leishmania chagasi/infantum: further investigations on Leishmania tropisms in atypical cutaneous and visceral leishmaniasis foci in Central America.

    NARCIS (Netherlands)

    Campos Ponce, M.; Ponce, C.; Ponce, E.; Maingon, R.D.

    2005-01-01

    In Central America, apparently genetically identical Leishmania chagasi/infantum parasites cause cutaneous (CL) and visceral leishmaniasis (VL), the latter being more frequent in young children. The present study investigated if there were pathology-related differences in virulence between Honduran

  7. Leishmania chagasi/infantum : further investigations on Leishmania tropisms in atypical cutaneous and visceral leishmaniasis foci in Central America

    NARCIS (Netherlands)

    Campos Ponce, M.; Ponce, C.; Ponce, E; Maingon, R.D.

    2005-01-01

    In Central America, apparently genetically identical Leishmania chagasi/infantum parasites cause cutaneous (CL) and visceral leishmaniasis (VL), the latter being more frequent in young children. The present study investigated if there were pathology-related differences in virulence between Honduran

  8. Leishmania (Viannia braziliensis em cães naturalmente infectados Leishmania (Viannia braziliensis in naturally infected dogs

    Directory of Open Access Journals (Sweden)

    Maria de Fátima Madeira

    2003-10-01

    Full Text Available Foram estudados oito cães provenientes do Município de Maricá (RJ, com lesões sugestivas de leishmaniose tegumentar americana por métodos parasitológicos e sorológicos. Leishmania spp foi encontrada em seis cães através do cultivo in vitro. Anticorpos específicos foram detectados em seis animais pelo ELISA e em dois pela imunofluorescência indireta. Cinco isolados caninos analisados apresentaram zimodema similar a Leishmania (Viannia braziliensis. Sugere-se que cães clinicamente suspeitos sejam acompanhados periodicamente, na tentativa de confirmar o diagnóstico da leishmaniose tegumentar canina.Eight dogs from Maricá Municipality (RJ, with suggestive lesion of american tegumentary leishmaniasis were studied by parasitological and serological methods. Leishmania spp was found in six dogs by in vitro cultivation. Specific antibodies were detected in six dogs by ELISA and in two by indirect immunofluorescence. Five canine isolates were found to belong to the same zymodeme as Leishmania (Viannia braziliensis. The authors suggest that clinically suspect dogs should be followed-up in an attempt to confirm the diagnostic of canine tegumentary leishmaniasis.

  9. Revealing the kinetics of Leishmania chagasi infection in the male genital system of hamsters.

    Science.gov (United States)

    Quintal, Amanda P N; Borges, Bruna C; Brígido, Paula C; Silva, Rebecca T; Notário, Ana F; Santos, Marlus A; de Souza, Maria A; Nascimento, Fernanda G O; Mundim, Antônio V; Costa, Guilherme M J; Vasconcelos, André B; da Silva, Claudio V

    2016-03-29

    Leishmaniasis causes alterations and lesions in the genital system, which leads to azoospermia and testicular atrophy in animals during the chronic phase of the infection. The aim of this study was to reveal the kinetics of Leishmania chagasi infection in the genital system of male golden hamsters (Mesocricetus auratus). Animals were intraperitoneally inoculated with amastigotes from L. chagasi. At different time points animals were euthanized and genital organs processed for histo-pathological, qPCR, cytokines and testosterone detection assays. Our results showed a high parasite load in testis, followed by an increase of pro-inflammatory cytokines IL1-β, TNF-α and IFN-γ, and testosterone. Subsequently, IL-4 expression was upregulated and basal parasite persistence in testis was observed using the experimental approach. Extracellular amastigotes migrated to the epididymis posing as a potential major factor of parasite persistence and venereal transmission of L. chagasi infection in hamsters.

  10. Identification of a Leishmania infantum gene mediating resistance to miltefosine and SbIII.

    Science.gov (United States)

    Choudhury, Kohelia; Zander, Dorothea; Kube, Michael; Reinhardt, Richard; Clos, Joachim

    2008-10-01

    Resistance to treatment is a growing problem in efforts to control Old World leishmaniasis. Parasites resistant to new therapeutics such as miltefosine have not been reported from the field yet but based on experimental evidence, may appear soon. Therefore, we attempted to identify genetic markers that may correlate with miltefosine resistance. Using a functional cloning approach, we have isolated a gene from Leishmania infantum that, upon over-expression, confers protection not only against miltefosine, but also against Sb(III), the active principle of anti-leishmanial antimonials. The gene encodes a very large putative polypeptide of 299 kDa that shows no similarities to known proteins or functional motifs. Database mining and karyotyping experiments suggest that in L. infantum this gene is part of a 44-kbp duplicated region that is found on two separate chromosomes, CHR08 and CHR29.

  11. No need for labels: the autofluorescence of Leishmania tarentolae mitochondria and the necessity of negative controls.

    Directory of Open Access Journals (Sweden)

    Elisabeth Eckers

    Full Text Available BACKGROUND: Fluorescence microscopy is a powerful tool to study the morphology and function of subcellular compartments or to determine the localization of proteins. The method is also regularly used for the analysis of parasitic protists including kinetoplastida. RESULTS: Here, we report a significant autofluorescence of Leishmania tarentolae mitochondria. The autofluorescence, presumably caused by flavoproteins, was detectable using a variety of cell fixation protocols and had a maximum emission at approximately 538 nm. Stable signals were obtained with xenon lamps as a light source and filter sets that are commonly used for the detection of green fluorescent protein. CONCLUSIONS: On the one hand, we present a methodological approach to examine mitochondrial morphology or to study the colocalization of mitochondrial proteins without additional staining or labeling procedures. On the other hand, under certain experimental conditions, mitochondrial autofluorescence can result in false positive signals, demonstrating the necessity to analyze unlabeled cells as negative controls.

  12. The Role of Vitamin D and Vitamin D Receptor in Immunity to Leishmania major Infection

    Directory of Open Access Journals (Sweden)

    James P. Whitcomb

    2012-01-01

    Full Text Available Vitamin D signaling modulates a variety of immune responses. Here, we assessed the role of vitamin D in immunity to experimental leishmaniasis infection in vitamin D receptor-deficient mice (VDRKO. We observed that VDRKO mice on a genetically resistant background have decreased Leishmania major-induced lesion development compared to wild-type (WT mice; additionally, parasite loads in infected dermis were significantly lower at the height of infection. Enzymatic depletion of the active form of vitamin D mimics the ablation of VDR resulting in an increased resistance to L. major. Conversely, VDRKO or vitamin D-deficient mice on the susceptible Th2-biased background had no change in susceptibility. These studies indicate vitamin D deficiency, either through the ablation of VDR or elimination of its ligand, 1,25D3, leads to an increase resistance to L. major infection but only in a host that is predisposed for Th-1 immune responses.

  13. Cross-protective efficacy of Leishmania infantum LiHyD protein against tegumentary leishmaniasis caused by Leishmania major and Leishmania braziliensis species.

    Science.gov (United States)

    Lage, Daniela Pagliara; Martins, Vívian Tamietti; Duarte, Mariana Costa; Costa, Lourena Emanuele; Tavares, Grasiele de Sousa Vieira; Ramos, Fernanda Fonseca; Chávez-Fumagalli, Miguel Angel; Menezes-Souza, Daniel; Roatt, Bruno Mendes; Tavares, Carlos Alberto Pereira; Coelho, Eduardo Antonio Ferraz

    2016-06-01

    Vaccination can be considered the most cost-effective strategy to control neglected diseases, but nowadays there is not an effective vaccine available against leishmaniasis. In the present study, a vaccine based on the combination of the Leishmania-specific hypothetical protein (LiHyD) with saponin was tested in BALB/c mice against infection caused by Leishmania major and Leishmania braziliensis species. This antigen was firstly identified in Leishmania infantum and showed to be protective against infection of BALB/c mice using this parasite species. The immunogenicity of rLiHyD/saponin vaccine was evaluated, and the results showed that immunized mice produced high levels of IFN-γ, IL-12 and GM-CSF after in vitro stimulation with rLiHyD, as well as by using L. major or L. braziliensis protein extracts. After challenge, vaccinated animals showed significant reductions in the infected footpad swellings, as well as in the parasite burden in the infection site, liver, spleen, and infected paws draining lymph nodes, when compared to those that were inoculated with the vaccine diluent (saline) or immunized with saponin. The immunization of rLiHyD without adjuvant was not protective against both challenges. The partial protection obtained by the rLiHyD/saponin vaccine was associated with a parasite-specific IL-12-dependent IFN-γ secretion, which was produced mainly by CD4(+) T cells. In these animals, a decrease in the parasite-mediated IL-4 and IL-10 responses, associated with the presence of high levels of LiHyD- and parasite-specific IgG2a isotype antibodies, were also observed. The present study showed that a hypothetical protein that was firstly identified in L. infantum, when combined to a Th1 adjuvant, was able to confer a cross-protection against highly infective stationary-phase promastigotes of two Leishmania species causing tegumentary leishmaniasis. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Post mortem parasitological evaluation of dogs seroreactive for Leishmania from Rio de Janeiro, Brazil.

    Science.gov (United States)

    de Fátima Madeira, Maria; de O Schubach, Armando; Schubach, Tânia M P; Pereira, Sandro A; Figueiredo, Fabiano B; Baptista, Cibele; Leal, Cristianni A; Melo, Cíntia X; Confort, Eliame M; Marzochi, Mauro C A

    2006-06-15

    A parasitological study was conducted on 66 dogs seroreactive for Leishmania captured as a control measure of visceral leishmaniasis in the State of Rio de Janeiro, Brazil. Biological samples from different anatomical sites were collected during autopsy of the animals and cultured on biphasic medium (NNN/Schneider). The Leishmania isolates were characterized by isoenzyme electrophoresis. Leishmania was isolated from 80.3% of the animals: 12 animals with Leishmania (Viannia) braziliensis isolated exclusively from cutaneous lesions, 39 with L. (L.) chagasi isolated from different sites in the same animal, and 2 with simultaneous isolation of L. (V.) braziliensis from cutaneous lesions and L. (L.) chagasi from different sites. Isolation in culture revealed the absence of Leishmania parasites in 13 animals. The results obtained confirm the existence of mixed infections in dogs in Rio de Janeiro and indicate the need to complement the investigation of seroreactive dogs using methods for the parasitological diagnosis and identification of Leishmania species.

  15. Role of pro-inflammatory cytokine IL-17 in Leishmania pathogenesis and in protective immunity by Leishmania vaccines.

    Science.gov (United States)

    Banerjee, Antara; Bhattacharya, Parna; Joshi, Amritanshu B; Ismail, Nevien; Dey, Ranadhir; Nakhasi, Hira L

    2016-11-01

    The clinical outcome of Leishmania pathogenesis ranges from active skin lesions to fatal visceral dissemination and severely impaired T cell immunity. It is well established that a strong Th1 immune response is protective against cutaneous forms of the disease, however a mixed Th1/Th2 response is most commonly observed against visceral infections as evident from previous studies. Aside from Th1/Th2 cytokines, the pro-inflammatory IL-17 cytokine family plays an important role in the clearance of intracellular pathogens. In Leishmania induced skin lesions, IL-17 produced by Th17 cells is shown to exacerbate the disease, suggesting a role in pathogenesis. However, a protective role for IL-17 is indicated by the expansion of IL-17 producing cells in vaccine-induced immunity. In human visceral leishmaniasis (VL) it has been demonstrated that IL-17 and IL-22 are associated with protection against re-exposure to Leishmania, which further suggests the involvement of IL-17 in vaccine induced protective immunity. Although there is no vaccine against any form of leishmaniasis, the development of genetically modified live attenuated parasites as vaccine candidates prove to be promising, as they successfully induce a robust protective immune response in various animal models. However, the role of IL-17 producing cells and Th17 cells in response to these vaccine candidates remains unexplored. In this article, we review the role of IL-17 in Leishmania pathogenesis and the potential impact on vaccine induced immunity, with a special focus on live attenuated Leishmania parasites. Published by Elsevier Inc.

  16. Unraveling the genetic diversity and phylogeny of Leishmania RNA virus 1 strains of infected Leishmania isolates circulating in French Guiana.

    Science.gov (United States)

    Tirera, Sourakhata; Ginouves, Marine; Donato, Damien; Caballero, Ignacio S; Bouchier, Christiane; Lavergne, Anne; Bourreau, Eliane; Mosnier, Emilie; Vantilcke, Vincent; Couppié, Pierre; Prevot, Ghislaine; Lacoste, Vincent

    2017-07-01

    Leishmania RNA virus type 1 (LRV1) is an endosymbiont of some Leishmania (Vianna) species in South America. Presence of LRV1 in parasites exacerbates disease severity in animal models and humans, related to a disproportioned innate immune response, and is correlated with drug treatment failures in humans. Although the virus was identified decades ago, its genomic diversity has been overlooked until now. We subjected LRV1 strains from 19 L. (V.) guyanensis and one L. (V.) braziliensis isolates obtained from cutaneous leishmaniasis samples identified throughout French Guiana with next-generation sequencing and de novo sequence assembly. We generated and analyzed 24 unique LRV1 sequences over their full-length coding regions. Multiple alignment of these new sequences revealed variability (0.5%-23.5%) across the entire sequence except for highly conserved motifs within the 5' untranslated region. Phylogenetic analyses showed that viral genomes of L. (V.) guyanensis grouped into five distinct clusters. They further showed a species-dependent clustering between viral genomes of L. (V.) guyanensis and L. (V.) braziliensis, confirming a long-term co-evolutionary history. Noteworthy, we identified cases of multiple LRV1 infections in three of the 20 Leishmania isolates. Here, we present the first-ever estimate of LRV1 genomic diversity that exists in Leishmania (V.) guyanensis parasites. Genetic characterization and phylogenetic analyses of these viruses has shed light on their evolutionary relationships. To our knowledge, this study is also the first to report cases of multiple LRV1 infections in some parasites. Finally, this work has made it possible to develop molecular tools for adequate identification and genotyping of LRV1 strains for diagnostic purposes. Given the suspected worsening role of LRV1 infection in the pathogenesis of human leishmaniasis, these data have a major impact from a clinical viewpoint and for the management of Leishmania-infected patients.

  17. Unraveling the genetic diversity and phylogeny of Leishmania RNA virus 1 strains of infected Leishmania isolates circulating in French Guiana.

    Directory of Open Access Journals (Sweden)

    Sourakhata Tirera

    2017-07-01

    Full Text Available Leishmania RNA virus type 1 (LRV1 is an endosymbiont of some Leishmania (Vianna species in South America. Presence of LRV1 in parasites exacerbates disease severity in animal models and humans, related to a disproportioned innate immune response, and is correlated with drug treatment failures in humans. Although the virus was identified decades ago, its genomic diversity has been overlooked until now.We subjected LRV1 strains from 19 L. (V. guyanensis and one L. (V. braziliensis isolates obtained from cutaneous leishmaniasis samples identified throughout French Guiana with next-generation sequencing and de novo sequence assembly. We generated and analyzed 24 unique LRV1 sequences over their full-length coding regions. Multiple alignment of these new sequences revealed variability (0.5%-23.5% across the entire sequence except for highly conserved motifs within the 5' untranslated region. Phylogenetic analyses showed that viral genomes of L. (V. guyanensis grouped into five distinct clusters. They further showed a species-dependent clustering between viral genomes of L. (V. guyanensis and L. (V. braziliensis, confirming a long-term co-evolutionary history. Noteworthy, we identified cases of multiple LRV1 infections in three of the 20 Leishmania isolates.Here, we present the first-ever estimate of LRV1 genomic diversity that exists in Leishmania (V. guyanensis parasites. Genetic characterization and phylogenetic analyses of these viruses has shed light on their evolutionary relationships. To our knowledge, this study is also the first to report cases of multiple LRV1 infections in some parasites. Finally, this work has made it possible to develop molecular tools for adequate identification and genotyping of LRV1 strains for diagnostic purposes. Given the suspected worsening role of LRV1 infection in the pathogenesis of human leishmaniasis, these data have a major impact from a clinical viewpoint and for the management of Leishmania

  18. A Leishmania murine model to evaluate the immunomodulatory properties of Pythium insidiosum proteins

    Directory of Open Access Journals (Sweden)

    Tatiana Maria Inêz-Ferreira

    2017-03-01

    Full Text Available Pythium insidiosum immunomodulatory vaccine (PiV has been tested in clinical and experimental pythiosis. Previous data showed that P. insidiosum immunogens have the ability to switch the Th2 immune response, normally in place during pythiosis, to a curative Th1 response. Pythiosis cannot be reproduced in experimental rodents with the exception of rabbits, and thus thorough evaluation of PiV´s immunomodulatory properties has been limited by the lack of a compatible inbred mouse model. In this study, we took advantage of the murine BALB/c Leishmania infection model, where infected mice produce a Th2 response, to evaluate the PiV Th2 to Th1 immunomodulatory potential. Twenty-one days following challenge with L. major, large cutaneous granulomas developed in control mice, consistent with the expected Th2 response. In contrast, Leishmania-induced cutaneous lesions in PiV-immunized mice were minimal or absent. Flow cytometry analysis of spleen cells from mice immunized with PiV and subsequently challenged with L. major displayed more CD4+ and CD8+ cells than the control group. Moreover, spleen cells from mice that were immunized with PiV then challenged with L. major secreted high levels of IFN-γ, with a moderate IL-2, IL-4, and IL-10 mixed cytokine profile upon in vitro re-stimulation with PiV. Anti-P. insidiosum IgG1 in immunized animals was present at low titers suggesting a minor immunological role for this Ig isotype in this model. Our preliminary data showed that BALB/c mice challenged with L. major represent an attractive model in which to study PiV´s immunomodulatory properties.

  19. Leishmania donovani complex: genotyping with the ribosomal internal transcribed spacer and the mini-exon

    OpenAIRE

    Mauricio, IL; Stothard, JR; Miles, MA

    2004-01-01

    Intergenic region typing by restriction analysis of the ribosomal internal transcribed spacer (ITS) and mini-exon provide diagnostic markers for some Leishmania. Here, we evaluate restriction analysis of these targets for genotyping and phylogenetic analysis within the Leishmania donovani complex (agents of visceral leishmaniasis). Each method was useful for genotyping of both L. donovani complex strains and Old World Leishmania species. The targets produced less robust groups than gp63 inter...

  20. Prevalence of Leishmania spp. infection in domestic dogs in Chapare, Bolivia.

    Science.gov (United States)

    Parrado, Rudy; Rojas, Ernesto; Delgado, Raúl; Torrico, Mary Cruz; Reithinger, Richard; Garcia, Ana Lineth

    2011-04-19

    Data on Leishmania spp. infection in dogs in Bolivia is scarce. Dogs from an area where 90% of human cutaneous leishmaniasis (CL) cases are due to Leishmania (Viannia) braziliensis were screened for Leishmania infection using established enzyme-linked immunosorbent antibody test (ELISA) protocols. Although none of the 51 dogs surveyed had clinical lesions indicative of CL, 6 out of 51 (11.8%) sampled dogs tested positive by ELISA. Copyright © 2010 Elsevier B.V. All rights reserved.

  1. Identificação de espécies de Leishmania isoladas de casos humanos em Mato Grosso do Sul por meio da reação em cadeia da polimerase Identification of Leishmania species isolated in human cases in Mato Grosso do Sul, by means of the polymerase chain reaction

    Directory of Open Access Journals (Sweden)

    Manoel Sebastião da Costa Lima Junior

    2009-06-01

    Full Text Available As leishmanioses são zoonoses endêmicas em Mato Grosso do Sul e têm por agentes etiológicos nessa região Leishmania (Leishmania chagasi, Leishmania (Leishmania amazonensis e Leishmania (Viannia braziliensis. Como método para identificação de espécies de Leishmania, a reação em cadeia da polimerase é uma ferramenta com elevada especificidade e sensibilidade. Analisaram-se 39 isolados de Leishmania criopreservados, obtidos por meio de aspirado medular e/ou biópsia de lesão, conforme a suspeita clínica. Os isolados foram submetidos à extração de DNA e à reação em cadeia da polimerase com os iniciadores: RV1/RV2 para Leishmania (Leishmania chagasi, a1/a2 para a identificação de Leishmania (Leishmania amazonensis e b1/b2 para Leishmania (Viannia braziliensis. Leishmania (Leishmania chagasi foi a única espécie identificada em 37 casos de leishmaniose visceral. Leishmania (Leishmania amazonensis foi identificada em dois isolados de pacientes com diagnóstico de leishmaniose tegumentar. Os resultados obtidos confirmam a possibilidade do uso dos três pares de iniciadores como uma ferramenta na caracterização de isolados de Leishmania.Leishmaniases are endemic zoonoses in the State of Mato Grosso do Sul. Their etiological agents in this region of Brazil are Leishmania (Leishmania chagasi, Leishmania (Leishmania amazonensis and Leishmania (Viannia braziliensis. The polymerase chain reaction (PCR is a tool with high specificity and sensitivity for identifying Leishmania species. This study examined 39 cryopreserved isolates of Leishmania that had been collected by bone marrow aspiration and/or lesion biopsy, depending on the clinical suspicion. The isolates were subjected to DNA extraction and PCR using the following primers: RV1/RV2 for identifying Leishmania (Leishmania chagasi, a1/a2 for Leishmania (Leishmania amazonensis and b1/b2 for Leishmania (Viannia braziliensis.Leishmania (Leishmania chagasi was the only species

  2. Role of efflux pumps and intracellular thiols in natural antimony resistant isolates of Leishmania donovani

    National Research Council Canada - National Science Library

    Rai, Smita; Bhaskar; Goel, Sudhir K; Nath Dwivedi, Upendra; Sundar, Shyam; Goyal, Neena

    2013-01-01

    .... Accordingly, the study of determinants of antimony resistance is urgently warranted. Efflux transporters have been reported in Leishmania but their role in clinical resistance is still unknown...

  3. Single-Step Multiplex PCR Assay for Characterization of New World Leishmania Complexes

    Science.gov (United States)

    Harris, Eva; Kropp, Gerald; Belli, Alejandro; Rodriguez, Betzabé; Agabian, Nina

    1998-01-01

    We have developed a PCR assay for one-step differentiation of the three complexes of New World Leishmania (Leishmania braziliensis, Leishmania mexicana, and Leishmania donovani). This multiplex assay is targeted to the spliced leader RNA (mini-exon) gene repeats of these organisms and can detect all three complexes simultaneously, generating differently sized products for each complex. The assay is specific to the Leishmania genus and does not recognize related kinetoplastid protozoa, such as Trypanosoma cruzi, Trypanosoma brucei, and Crithidia fasciculata. It correctly identified Leishmania species with a broad geographic distribution in Central and South America. The sensitivity of the PCR amplification ranged from 1 fg to 10 pg of DNA (0.01 to 100 parasites), depending on the complex detected. Crude extracts of cultured parasites, prepared simply by boiling diluted cultures, served as excellent templates for amplification. Crude preparations of clinical material were also tested. The assay detected L. braziliensis in dermal scrapings from cutaneous leishmanial lesions, Leishmania chagasi in dermal scrapings of atypical cutaneous leishmaniasis, and L. mexicana from lesion aspirates from infected hamsters. We have minimized the material requirements and maximized the simplicity, rapidity, and informative content of this assay to render it suitable for use in laboratories in countries where leishmaniasis is endemic. This assay should be useful for rapid in-country identification of Leishmania parasites, particularly where different Leishmania complexes are found in the same geographical area. PMID:9650950

  4. Immucillins Impair Leishmania (L. infantum chagasi and Leishmania (L. amazonensis Multiplication In Vitro.

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    Elisangela Oliveira Freitas

    Full Text Available Chemotherapy against visceral leishmaniasis is associated with high toxicity and drug resistance. Leishmania parasites are purine auxotrophs that obtain their purines from exogenous sources. Nucleoside hydrolases release purines from nucleosides and are drug targets for anti-leishmanial drugs, absent in mammal cells. We investigated the substrate specificity of the Leishmania (L. donovani recombinant nucleoside hydrolase NH36 and the inhibitory effect of the immucillins IA (ImmA, DIA (DADMe-ImmA, DIH (DADMe-ImmH, SMIH (SerMe-ImmH, IH (ImmH, DIG (DADMe-ImmG, SMIG (SerMe-ImmG and SMIA (SerME-ImmA on its enzymatic activity. The inhibitory effects of immucillins on the in vitro multiplication of L. (L. infantum chagasi and L. (L. amazonensis promastigotes were determined using 0.05-500 μM and, when needed, 0.01-50 nM of each drug. The inhibition on multiplication of L. (L. infantum chagasi intracellular amastigotes in vitro was assayed using 0.5, 1, 5 and 10 μM of IA, IH and SMIH. The NH36 shows specificity for inosine, guanosine, adenosine, uridine and cytidine with preference for adenosine and inosine. IA, IH, DIH, DIG, SMIH and SMIG immucillins inhibited L. (L. infantum chagasi and L. (L. amazonensis promastigote growth in vitro at nanomolar to micromolar concentrations. Promastigote replication was also inhibited in a chemically defined medium without a nucleoside source. Addition of adenosine decreases the immucillin toxicity. IA and IH inhibited the NH36 enzymatic activity (Ki = 0.080 μM for IA and 0.019 μM for IH. IA, IH and SMIH at 10 μM concentration, reduced the in vitro amastigote replication inside mice macrophages by 95% with no apparent effect on macrophage viability. Transmission electron microscopy revealed global alterations and swelling of L. (L. infantum chagasi promastigotes after treatment with IA and IH while SMIH treatment determined intense cytoplasm vacuolization, enlarged vesicles and altered kinetoplasts. Our results

  5. Immucillins Impair Leishmania (L.) infantum chagasi and Leishmania (L.) amazonensis Multiplication In Vitro.

    Science.gov (United States)

    Freitas, Elisangela Oliveira; Nico, Dirlei; Guan, Rong; Meyer-Fernandes, José Roberto; Clinch, Keith; Evans, Gary B; Tyler, Peter C; Schramm, Vern L; Palatnik-de-Sousa, Clarisa B

    2015-01-01

    Chemotherapy against visceral leishmaniasis is associated with high toxicity and drug resistance. Leishmania parasites are purine auxotrophs that obtain their purines from exogenous sources. Nucleoside hydrolases release purines from nucleosides and are drug targets for anti-leishmanial drugs, absent in mammal cells. We investigated the substrate specificity of the Leishmania (L.) donovani recombinant nucleoside hydrolase NH36 and the inhibitory effect of the immucillins IA (ImmA), DIA (DADMe-ImmA), DIH (DADMe-ImmH), SMIH (SerMe-ImmH), IH (ImmH), DIG (DADMe-ImmG), SMIG (SerMe-ImmG) and SMIA (SerME-ImmA) on its enzymatic activity. The inhibitory effects of immucillins on the in vitro multiplication of L. (L.) infantum chagasi and L. (L.) amazonensis promastigotes were determined using 0.05-500 μM and, when needed, 0.01-50 nM of each drug. The inhibition on multiplication of L. (L.) infantum chagasi intracellular amastigotes in vitro was assayed using 0.5, 1, 5 and 10 μM of IA, IH and SMIH. The NH36 shows specificity for inosine, guanosine, adenosine, uridine and cytidine with preference for adenosine and inosine. IA, IH, DIH, DIG, SMIH and SMIG immucillins inhibited L. (L.) infantum chagasi and L. (L.) amazonensis promastigote growth in vitro at nanomolar to micromolar concentrations. Promastigote replication was also inhibited in a chemically defined medium without a nucleoside source. Addition of adenosine decreases the immucillin toxicity. IA and IH inhibited the NH36 enzymatic activity (Ki = 0.080 μM for IA and 0.019 μM for IH). IA, IH and SMIH at 10 μM concentration, reduced the in vitro amastigote replication inside mice macrophages by 95% with no apparent effect on macrophage viability. Transmission electron microscopy revealed global alterations and swelling of L. (L.) infantum chagasi promastigotes after treatment with IA and IH while SMIH treatment determined intense cytoplasm vacuolization, enlarged vesicles and altered kinetoplasts. Our results

  6. Towards an unbiased metabolic profiling of protozoan parasites : optimisation of a Leishmania sampling protocol for HILIC-orbitrap analysis

    NARCIS (Netherlands)

    t'Kindt, Ruben; Jankevics, Andris; Scheltema, Richard A.; Zheng, Liang; Watson, David G.; Dujardin, Jean-Claude; Breitling, Rainer; Coombs, Graham H.; Decuypere, Saskia; Kindt, Ruben t’

    2010-01-01

    Comparative metabolomics of Leishmania species requires the simultaneous identification and quantification of a large number of intracellular metabolites. Here, we describe the optimisation of a comprehensive metabolite extraction protocol for Leishmania parasites and the subsequent optimisation of

  7. Modulation of Innate Immune Mechanisms to Enhance Leishmania Vaccine-Induced Immunity: Role of Coinhibitory Molecules.

    Science.gov (United States)

    Gannavaram, Sreenivas; Bhattacharya, Parna; Ismail, Nevien; Kaul, Amit; Singh, Rakesh; Nakhasi, Hira L

    2016-01-01

    No licensed human vaccines are currently available against any parasitic disease including leishmaniasis. Several antileishmanial vaccine formulations have been tested in various animal models, including genetically modified live-attenuated parasite vaccines. Experimental infection studies have shown that Leishmania parasites utilize a broad range of strategies to undermine effector properties of host phagocytic cells, i.e., dendritic cells (DCs) and macrophages (MΦ). Furthermore, Leishmania parasites have evolved strategies to actively inhibit TH1 polarizing functions of DCs and to condition the infected MΦ toward anti-inflammatory/alternative/M2 phenotype. The altered phenotype of phagocytic cells is characterized by decreased production of antimicrobial reactive oxygen, nitrogen molecules, and pro-inflammatory cytokines, such as IFN-γ, IL-12, and TNF-α. These early events limit the activation of TH1-effector cells and set the stage for pathogenesis. Furthermore, this early control of innate immunity by the virulent parasites results in substantial alteration in the adaptive immunity characterized by reduced proliferation of CD4(+) and CD8(+) T cells and TH2-biased immunity that results in production of anti-inflammatory cytokines, such as TGF-β, and IL-10. More recent studies have also documented the induction of coinhibitory ligands, such as CTLA-4, PD-L1, CD200, and Tim-3, that induce exhaustion and/or non-proliferation in antigen-experienced T cells. Most of these studies focus on viral infections in chronic phase, thus limiting the direct application of these results to parasitic infections and much less to parasitic vaccines. However, these studies suggest that vaccine-induced protective immunity can be modulated using strategies that enhance the costimulation that might reduce the threshold necessary for T cell activation and conversely by strategies that reduce or block inhibitory molecules, such as PD-L1 and CD200. In this review, we will focus on

  8. An agent-based model for Leishmania major infection

    Science.gov (United States)

    Dancik, Garrett M.; Jones, Douglas E.; Dorman, Karin S.

    Leishmania are protozoan parasites transmitted by bites of infected sandflies. Over 20 species of Leishmania, endemic in 88 countries, are capable of causing human disease. Disease is either cutaneous, where skin ulcers occur on exposed surfaces of the body, or visceral, with near certain mortality if untreated. C3HeB/FeJ mice are resistant to L. major, but develop chronic cutaneous lesions when infected with another species L. amazonensis. The well-characterized mechanism of resistance to L. major depends on a CD4+ Thl immune response, macrophage activation, and elimination of the parasite [Sacks 2002]. The factors that account for host susceptibility to L. Amazonensis, however, are not completely understood, despite being generally attributed to a weakened Th1 response [Vanloubbeck 2004].

  9. Post-Genomics and Vaccine Improvement for Leishmania

    Science.gov (United States)

    Seyed, Negar; Taheri, Tahereh; Rafati, Sima

    2016-01-01

    Leishmaniasis is a parasitic disease that primarily affects Asia, Africa, South America, and the Mediterranean basin. Despite extensive efforts to develop an effective prophylactic vaccine, no promising vaccine is available yet. However, recent advancements in computational vaccinology on the one hand and genome sequencing approaches on the other have generated new hopes in vaccine development. Computational genome mining for new vaccine candidates is known as reverse vaccinology and is believed to further extend the current list of Leishmania vaccine candidates. Reverse vaccinology can also reduce the intrinsic risks associated with live attenuated vaccines. Individual epitopes arranged in tandem as polytopes are also a possible outcome of reverse genome mining. Here, we will briefly compare reverse vaccinology with conventional vaccinology in respect to Leishmania vaccine, and we will discuss how it influences the aforementioned topics. We will also introduce new in vivo models that will bridge the gap between human and laboratory animal models in future studies. PMID:27092123

  10. Leishmania promastigotes: building a safe niche within macrophages

    Directory of Open Access Journals (Sweden)

    Neda eMoradin

    2012-09-01

    Full Text Available Upon their internalization by macrophages, Leishmania promastigotes inhibit phagolysosome biogenesis. The main factor responsible for this inhibition is the promastigote surface glycolipid lipophosphoglycan (LPG. This glycolipid has a profound impact on the phagosome, causing periphagosomal accumulation of F-actin and disruption of phagosomal lipid microdomains. Functionally, this LPG-mediated inhibition of phagosome maturation is characterized by an impaired assembly of the NADPH oxidase and the exclusion of the vesicular proton-ATPase from phagosomes. In this chapter, we review the current knowledge concerning the nature of the intra-macrophage compartment in which Leishmania donovani promastigotes establish infection. We also describe how LPG enables this parasite to remodel the parasitophorous vacuole.

  11. Dynamic of the Cellular Immune Response at the Dermal Site of Leishmania (L. amazonensis and Leishmania (V. braziliensis Infection in Sapajus apella Primate

    Directory of Open Access Journals (Sweden)

    Márcia Dalastra Laurenti

    2014-01-01

    Full Text Available The purpose of this study was to characterize the immunopathological response in the skin of S. apella infected with Leishmania (L. amazonensis and L. (V. braziliensis parasites, the main causative agents of localized cutaneous leishmaniasis in South America. In infected animals, amastigote forms of L. (L. amazonensis could be detected till 120 days postinfection (PI, while, in L. (V. braziliensis infection, parasites could be detected until 180 days PI in the skin sections. CD20+ cells were detected throughout the experimental time in both groups as well as in CD3+ cells, which appeared to be activated because high densities of inducible nitric oxide synthase (iNOS+ cells were detected at 60 and 90 days PI in both studied groups. After 60 and 120 days PI, decrease in iNOS+ cells was observed in L. (L. amazonensis and L. (V. braziliensis, respectively, which was associated with parasite clearance. Increase in lysozyme+ cells was observed during the experimental infections, which also can be associated with parasite killing.

  12. Tyrosine aminotransferase from Leishmania infantum: A new drug target candidate

    OpenAIRE

    Moreno-Izquierdo, Miguel A.; Alonso, Ana; Alcolea, Pedro J.; García de Lacoba, Mario; Larraga, Vicente

    2014-01-01

    Leishmania infantum is the etiological agent of zoonotic visceral leishmaniasis in the Mediterranean basin. The disease is fatal without treatment, which has been based on antimonial pentavalents for more than 60 years. Due to resistances, relapses and toxicity to current treatment, the development of new drugs is required. The structure of the L. infantum tyrosine aminotransferase (LiTAT) has been recently solved showing important differences with the mammalian orthologue. The characterizati...

  13. Advanced Developement of Leishmania Tropical Skin Test Antigen

    Science.gov (United States)

    2011-09-01

    L. mexicana and to a lesser degree in Trypanosoma cruzi and T. brucei. 4.1.6 Validations Performed During Reporting Period Validation Protocol...kDa have a high degree of similarity to proteins of braziliensis, L. infantum, L. mexicana and to a lesser degree in Trypanosoma cruzi and T. brucei...compared dominant proteins in promastigote lysate with other Leishmania species, Trypanosoma , misc. biological materials and humans. 3.2.5

  14. Human mixed infections of Leishmania spp. and Leishmania-Trypanosoma cruzi in a sub Andean Bolivian area: identification by polymerase chain reaction/hybridization and isoenzyme

    Directory of Open Access Journals (Sweden)

    B Bastrenta

    2003-03-01

    Full Text Available Parasites belonging to Leishmania braziliensis, Leishmania donovani, Leishmania mexicana complexes and Trypanosoma cruzi (clones 20 and 39 were searched in blood, lesions and strains collected from 28 patients with active cutaneous leishmaniasis and one patient with visceral leishmaniasis. PCR-hybridization with specific probes of Leishmania complexes (L. braziliensis, L. donovani and L. mexicana and T. cruzi clones was applied to the different DNA samples. Over 29 patients, 8 (27.6% presented a mixed infection Leishmania complex species, 17 (58.6% a mixed infection Leishmania-T. cruzi, and 4 (13.8% a multi Leishmania-T. cruzi infection. Several patients were infected by the two Bolivian major clones 20 and 39 of T. cruzi (44.8%. The L. braziliensis complex was more frequently detected in lesions than in blood and a reverse result was observed for L. mexicana complex. The polymerase chain reaction-hybridization design offers new arguments supporting the idea of an underestimated rate of visceral leishmanisis in Bolivia. Parasites were isolated by culture from the blood of two patients and lesions of 10 patients. The UPGMA (unweighted pair-group method with arithmetic averages dendrogram computed from Jaccard's distances obtained from 11 isoenzyme loci data confirmed the presence of the three Leishmania complexes and undoubtedly identified human infections by L. (V. braziliensis, L. (L. chagasi and L. (L. mexicana species. Additional evidence of parasite mixtures was visualized through mixed isoenzyme profiles, L. (V. braziliensis-L. (L. mexicana and Leishmania spp.-T. cruzi.The epidemiological profile in the studied area appeared more complex than currently known. This is the first report of parasitological evidence of Bolivian patients with trypanosomatidae multi infections and consequences on the diseases' control and patient treatments are discussed.

  15. Serial Quantitative PCR Assay for Detection, Species Discrimination, and Quantification of Leishmania spp. in Human Samples▿

    Science.gov (United States)

    Weirather, Jason L.; Jeronimo, Selma M. B.; Gautam, Shalini; Sundar, Shyam; Kang, Mitchell; Kurtz, Melissa A.; Haque, Rashidul; Schriefer, Albert; Talhari, Sinésio; Carvalho, Edgar M.; Donelson, John E.; Wilson, Mary E.

    2011-01-01

    The Leishmania species cause a variety of human disease syndromes. Methods for diagnosis and species differentiation are insensitive and many require invasive sampling. Although quantitative PCR (qPCR) methods are reported for leishmania detection, no systematic method to quantify parasites and determine the species in clinical specimens is established. We developed a serial qPCR strategy to identify and rapidly differentiate Leishmania species and quantify parasites in clinical or environmental specimens. SYBR green qPCR is mainly employed, with corresponding TaqMan assays for validation. The screening primers recognize kinetoplast minicircle DNA of all Leishmania species. Species identification employs further qPCR set(s) individualized for geographic regions, combining species-discriminating probes with melt curve analysis. The assay was sufficient to detect Leishmania parasites, make species determinations, and quantify Leishmania spp. in sera, cutaneous biopsy specimens, or cultured isolates from subjects from Bangladesh or Brazil with different forms of leishmaniasis. The multicopy kinetoplast DNA (kDNA) probes were the most sensitive and useful for quantification based on promastigote standard curves. To test their validity for quantification, kDNA copy numbers were compared between Leishmania species, isolates, and life stages using qPCR. Maxicircle and minicircle copy numbers differed up to 6-fold between Leishmania species, but the differences were smaller between strains of the same species. Amastigote and promastigote leishmania life stages retained similar numbers of kDNA maxi- or minicircles. Thus, serial qPCR is useful for leishmania detection and species determination and for absolute quantification when compared to a standard curve from the same Leishmania species. PMID:22042830

  16. The Dynamics of Lateral Gene Transfer in Genus Leishmania - A Route for Adaptation and Species Diversification.

    Science.gov (United States)

    Vikeved, Elisabet; Backlund, Anders; Alsmark, Cecilia

    2016-01-01

    The genome of Leishmania major harbours a comparably high proportion of genes of prokaryote origin, acquired by lateral gene transfer (LGT). Some of these are present in closely related trypanosomatids, while some are detected in Leishmania only. We have evaluated the impact and destiny of LGT in genus Leishmania. To study the dynamics and fate of LGTs we have performed phylogenetic, as well as nucleotide and amino acid composition analyses within orthologous groups of LGTs detected in Leishmania. A set of universal trypanosomatid LGTs was added as a reference group. Both groups of LGTs have, to some extent, ameliorated to resemble the recipient genomes. However, while virtually all of the universal trypanosomatid LGTs are distributed and conserved in the entire genus Leishmania, the LGTs uniquely present in genus Leishmania are more prone to gene loss and display faster rates of evolution. Furthermore, a PCR based approach has been employed to ascertain the presence of a set of twenty LGTs uniquely present in genus Leishmania, and three universal trypanosomatid LGTs, in ten additional strains of Leishmania. Evolutionary rates and predicted expression levels of these LGTs have also been estimated. Ten of the twenty LGTs are distributed and conserved in all species investigated, while the remainder have been subjected to modifications, or undergone pseudogenization, degradation or loss in one or more species. LGTs unique to the genus Leishmania have been acquired after the divergence of Leishmania from the other trypanosomatids, and are evolving faster than their recipient genomes. This implies that LGT in genus Leishmania is a continuous and dynamic process contributing to species differentiation and speciation. This study also highlights the importance of carefully evaluating these dynamic genes, e.g. as LGTs have been suggested as potential drug targets.

  17. A Historical Overview of the Classification, Evolution, and Dispersion of Leishmania Parasites and Sandflies.

    Science.gov (United States)

    Akhoundi, Mohammad; Kuhls, Katrin; Cannet, Arnaud; Votýpka, Jan; Marty, Pierre; Delaunay, Pascal; Sereno, Denis

    2016-03-01

    The aim of this study is to describe the major evolutionary historical events among Leishmania, sandflies, and the associated animal reservoirs in detail, in accordance with the geographical evolution of the Earth, which has not been previously discussed on a large scale. Leishmania and sandfly classification has always been a controversial matter, and the increasing number of species currently described further complicates this issue. Despite several hypotheses on the origin, evolution, and distribution of Leishmania and sandflies in the Old and New World, no consistent agreement exists regarding dissemination of the actors that play roles in leishmaniasis. For this purpose, we present here three centuries of research on sandflies and Leishmania descriptions, as well as a complete description of Leishmania and sandfly fossils and the emergence date of each Leishmania and sandfly group during different geographical periods, from 550 million years ago until now. We discuss critically the different approaches that were used for Leishmana and sandfly classification and their synonymies, proposing an updated classification for each species of Leishmania and sandfly. We update information on the current distribution and dispersion of different species of Leishmania (53), sandflies (more than 800 at genus or subgenus level), and animal reservoirs in each of the following geographical ecozones: Palearctic, Nearctic, Neotropic, Afrotropical, Oriental, Malagasy, and Australian. We propose an updated list of the potential and proven sandfly vectors for each Leishmania species in the Old and New World. Finally, we address a classical question about digenetic Leishmania evolution: which was the first host, a vertebrate or an invertebrate? We propose an updated view of events that have played important roles in the geographical dispersion of sandflies, in relation to both the Leishmania species they transmit and the animal reservoirs of the parasites.

  18. The Dynamics of Lateral Gene Transfer in Genus Leishmania - A Route for Adaptation and Species Diversification.

    Directory of Open Access Journals (Sweden)

    Elisabet Vikeved

    2016-01-01

    Full Text Available The genome of Leishmania major harbours a comparably high proportion of genes of prokaryote origin, acquired by lateral gene transfer (LGT. Some of these are present in closely related trypanosomatids, while some are detected in Leishmania only. We have evaluated the impact and destiny of LGT in genus Leishmania.To study the dynamics and fate of LGTs we have performed phylogenetic, as well as nucleotide and amino acid composition analyses within orthologous groups of LGTs detected in Leishmania. A set of universal trypanosomatid LGTs was added as a reference group. Both groups of LGTs have, to some extent, ameliorated to resemble the recipient genomes. However, while virtually all of the universal trypanosomatid LGTs are distributed and conserved in the entire genus Leishmania, the LGTs uniquely present in genus Leishmania are more prone to gene loss and display faster rates of evolution. Furthermore, a PCR based approach has been employed to ascertain the presence of a set of twenty LGTs uniquely present in genus Leishmania, and three universal trypanosomatid LGTs, in ten additional strains of Leishmania. Evolutionary rates and predicted expression levels of these LGTs have also been estimated. Ten of the twenty LGTs are distributed and conserved in all species investigated, while the remainder have been subjected to modifications, or undergone pseudogenization, degradation or loss in one or more species.LGTs unique to the genus Leishmania have been acquired after the divergence of Leishmania from the other trypanosomatids, and are evolving faster than their recipient genomes. This implies that LGT in genus Leishmania is a continuous and dynamic process contributing to species differentiation and speciation. This study also highlights the importance of carefully evaluating these dynamic genes, e.g. as LGTs have been suggested as potential drug targets.

  19. Reduced antimony accumulation in ARM58-overexpressing Leishmania infantum.

    Science.gov (United States)

    Schäfer, Carola; Tejera Nevado, Paloma; Zander, Dorothea; Clos, Joachim

    2014-01-01

    Antimony-based drugs are still the mainstay of chemotherapy against Leishmania infections in many countries where the parasites are endemic. The efficacy of antimonials has been compromised by increasing numbers of resistant infections, the basis of which is not fully understood and likely involves multiple factors. By using a functional cloning strategy, we recently identified a novel antimony resistance marker, ARM58, from the parasite Leishmania braziliensis that protects the parasites against antimony-based antileishmanial compounds. Here we show that the Leishmania infantum homologue also confers resistance against antimony but not against other antileishmanial drugs and that its function depends critically on one of four conserved domains of unknown function. This critical domain requires at least two hydrophobic amino acids and is predicted to form a transmembrane structure. Overexpression of ARM58 in antimony-exposed parasites reduces the intracellular Sb accumulation by over 70%, indicating a role for ARM58 in Sb extrusion pathways, but without involvement of energy-dependent transporter proteins.

  20. [Cutaneous leishmaniasis due to Leishmania infantum associated with HIV].

    Science.gov (United States)

    Diatta, B-A; Diallo, M; Diadie, S; Faye, B; Ndiaye, M; Hakim, H; Diallo, S; Seck, B; Niang, S-O; Kane, A; Dieng, M-T

    2016-10-01

    In Senegal, reported cases of cutaneous leishmaniasis are often due to Leishmania major. Immunosuppression related to HIV infection contributes to the emergence of leishmaniasis in humans and to cutaneous localization of viscerotropic species. We report the first observed case in Senegal of opportunistic cutaneous leishmaniasis due to Leishmania infantum associated with HIV. A 5-year-old boy presented crusted ulcerative lesions of the scalp and left forearm, together with axillary and cervical lymphadenopathy present for two months. Direct parasitological examination of the scalp and arm lesions, coupled with liquid aspiration of lymph nodes and bone marrow, enabled identification of amastigote forms of Leishmania. Polymerase chain reaction performed on skin, lymph node and bone marrow biopsy samples allowed identification of L. infantum. The child was positive for HIV1. Treatment of HIV infection and leishmaniasis resulted in clinical improvement. Co-infection with cutaneous leishmaniasis due to L. infantum and HIV is a complex combination in terms of the related therapeutic issues. The clinical and laboratory outcomes depend on restoration of immunity and on the efficacy, safety and availability of anti-leishmaniasis drugs. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  1. Molecular epidemiology of Leishmania (Viannia) guyanensis in French Guiana.

    Science.gov (United States)

    Rotureau, Brice; Ravel, Christophe; Nacher, Mathieu; Couppié, Pierre; Curtet, Isabelle; Dedet, Jean-Pierre; Carme, Bernard

    2006-02-01

    Little information is available about the genetic variability of Leishmania populations and the possible correlations with ecoepidemiological features of leishmaniases. The present study was carried out in French Guiana, a country where cutaneous leishmaniases (CL) are endemic over the whole territory. The genetic polymorphism of a nuclear sequence encompassing the end of the ribosomal small subunit and the internal transcribed spacer 1 of 265 isolates from patients with CL was examined by restriction fragment length polymorphism analysis. Genotypes based on the fingerprinting phenetic integration were compared to epidemiological, clinical, and geographical data. In agreement with previous reports, five different Leishmania species were identified, but Leishmania (Viannia) guyanensis represented 95.8% of the samples. Two distinct L. (V.) guyanensis populations were found to originate in two ecologically characterized regions. Higher lesional parasite densities and the need for additional treatments were significantly linked to genotype group I. Parasites of genotype group II were more likely to cause chronic and disseminated cutaneous forms in patients. L. (V.) guyanensis was previously said not to be very polymorphic; however, the present analysis resulted in a significant degree of discrimination among L. (V.) guyanensis isolates from diverse ecological areas and with different clinical implications.

  2. Leishmania and its quest for iron: An update and overview.

    Science.gov (United States)

    Zaidi, Amir; Singh, Krishn Pratap; Ali, Vahab

    2017-01-01

    Parasites of genus Leishmania are the causative agents of complex neglected diseases called leishmaniasis and continue to be a significant health concern globally. Iron is a vital nutritional requirement for virtually all organisms, including pathogenic trypanosomatid parasites, and plays a crucial role in many facets of cellular metabolism as a cofactor of several enzymes. Iron acquisition is essential for the survival of parasites. Yet parasites are also vulnerable to the toxicity of iron and reactive oxygen species. The aim of this review is to provide an update on the current knowledge about iron acquisition and usage by Leishmania species. We have also discussed about host strategy to modulate iron availability and the strategies deployed by Leishmania parasites to overcome iron withholding defences and thus favour parasite growth within host macrophages. Since iron plays central roles in the host's response and parasite metabolism, a comprehensive understanding of the iron metabolism is beneficial to identify potential viable therapeutic opportunities against leishmaniasis. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Deception and Manipulation: The Arms of Leishmania, a Successful Parasite

    Science.gov (United States)

    Cecílio, Pedro; Pérez-Cabezas, Begoña; Santarém, Nuno; Maciel, Joana; Rodrigues, Vasco; Cordeiro da Silva, Anabela

    2014-01-01

    Leishmania spp. are intracellular parasitic protozoa responsible for a group of neglected tropical diseases, endemic in 98 countries around the world, called leishmaniasis. These parasites have a complex digenetic life cycle requiring a susceptible vertebrate host and a permissive insect vector, which allow their transmission. The clinical manifestations associated with leishmaniasis depend on complex interactions between the parasite and the host immune system. Consequently, leishmaniasis can be manifested as a self-healing cutaneous affliction or a visceral pathology, being the last one fatal in 85–90% of untreated cases. As a result of a long host–parasite co-evolutionary process, Leishmania spp. developed different immunomodulatory strategies that are essential for the establishment of infection. Only through deception and manipulation of the immune system, Leishmania spp. can complete its life cycle and survive. The understanding of the mechanisms associated with immune evasion and disease progression is essential for the development of novel therapies and vaccine approaches. Here, we revise how the parasite manipulates cell death and immune responses to survive and thrive in the shadow of the immune system. PMID:25368612

  4. Impact of Leishmania metalloprotease GP63 on macrophage signaling

    Science.gov (United States)

    Isnard, Amandine; Shio, Marina T.; Olivier, Martin

    2012-01-01

    The intramacrophage protozoan parasites of Leishmania genus have developed sophisticated ways to subvert the innate immune response permitting their infection and propagation within the macrophages of the mammalian host. Several Leishmania virulence factors have been identified and found to be of importance for the development of leishmaniasis. However, recent findings are now further reinforcing the critical role played by the zinc-metalloprotease GP63 as a virulence factor that greatly influence host cell signaling mechanisms and related functions. GP63 has been found to be involved not only in the cleavage and degradation of various kinases and transcription factors, but also to be the major molecule modulating host negative regulatory mechanisms involving for instance protein tyrosine phosphatases (PTPs). Those latter being well recognized for their pivotal role in the regulation of a great number of signaling pathways. In this review article, we are providing a complete overview about the role of Leishmania GP63 in the mechanisms underlying the subversion of macrophage signaling and functions. PMID:22919663

  5. Transmission of Leishmania in coffee plantations of Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Bruce Alexander

    2002-07-01

    Full Text Available Transmission of Leishmania was studied in 27 coffee plantations in the Brazilian State of Minas Gerais. Eighteen females and six males (11.6% of the people tested, aged between 7-65 gave a positive response to the Montenegro skin test. Awareness of sand flies based on the ability of respondents to identify the insects using up to seven predetermined characteristics was significantly greater among inhabitants of houses occupied by at least one Mn+ve individual. Five species of phlebotomine sand fly, including three suspected Leishmania vectors, were collected within plantations under three different cultivation systems. Four of these species i.e., Lu. fischeri (Pinto 1926, Lu. migonei (França 1920, Lu. misionensis (Castro 1959 and Lutzomyia whitmani (Antunes & Coutinho 1939 were collected in an organic plantation and the last of these was also present in the other two plantation types. The remaining species, Lu. intermedia (Lutz & Neiva 1912, was collected in plantations under both the "adensado" and "convencional" systems. The results of this study indicate that transmission of Leishmania to man in coffee-growing areas of Minas Gerais may involve phlebotomine sand flies that inhabit plantations.

  6. Leishmania (Viannia) infection in the domestic dog in Chaparral, Colombia.

    Science.gov (United States)

    Santaella, Julián; Ocampo, Clara B; Saravia, Nancy G; Méndez, Fabián; Góngora, Rafael; Gomez, Maria Adelaida; Munstermann, Leonard E; Quinnell, Rupert J

    2011-05-01

    Peridomestic transmission of American cutaneous leishmaniasis is increasingly reported and dogs may be a reservoir of Leishmania (Viannia) in this setting. We investigated the prevalence of infection in dogs in Chaparral County, Colombia, the focus of an epidemic of human cutaneous leishmaniasis caused by Leishmania (Viannia) guyanensis. Two (0.72%) of 279 dogs had lesions typical of cutaneous leishmaniasis that were biopsy positive by kinetoplast DNA polymerase chain reaction-Southern blotting. Seroprevalence was 2.2% (6 of 279) by enzyme-linked immunosorbent assay. Buffy coat and ear skin biopsy specimens were positive by polymerase chain reaction-Southern blotting in 7.3% (10 of 137) and 11.4% (12 of 105) of dogs, respectively. Overall 20% of dogs (21 of 105) showed positive results for one or more tests. Amplification and sequencing of the Leishmania 7SL RNA gene identified L. guyanensis in one dog and L. braziliensis in two dogs. No association was identified between the risk factors evaluated and canine infection. Dogs may contribute to transmission but their role in this focus appears to be limited.

  7. Leishmania (Viannia) Infection in the Domestic Dog in Chaparral, Colombia

    Science.gov (United States)

    Santaella, Julián; Ocampo, Clara B.; Saravia, Nancy G.; Méndez, Fabián; Góngora, Rafael; Gomez, Maria Adelaida; Munstermann, Leonard E.; Quinnell, Rupert J.

    2011-01-01

    Peridomestic transmission of American cutaneous leishmaniasis is increasingly reported and dogs may be a reservoir of Leishmania (Viannia) in this setting. We investigated the prevalence of infection in dogs in Chaparral County, Colombia, the focus of an epidemic of human cutaneous leishmaniasis caused by Leishmania (Viannia) guyanensis. Two (0.72%) of 279 dogs had lesions typical of cutaneous leishmaniasis that were biopsy positive by kinetoplast DNA polymerase chain reaction–Southern blotting. Seroprevalence was 2.2% (6 of 279) by enzyme-linked immunosorbent assay. Buffy coat and ear skin biopsy specimens were positive by polymerase chain reaction–Southern blotting in 7.3% (10 of 137) and 11.4% (12 of 105) of dogs, respectively. Overall 20% of dogs (21 of 105) showed positive results for one or more tests. Amplification and sequencing of the Leishmania 7SL RNA gene identified L. guyanensis in one dog and L. braziliensis in two dogs. No association was identified between the risk factors evaluated and canine infection. Dogs may contribute to transmission but their role in this focus appears to be limited. PMID:21540374

  8. Leishmania infantum AS A CAUSATIVE AGENT OF CUTANEOUS LEISHMANIASIS IN THE STATE OF MATO GROSSO DO SUL, BRAZIL

    OpenAIRE

    CASTRO, Ludiele Souza; FRANÇA, Adriana de Oliveira; FERREIRA, Eduardo de Castro; HANS FILHO, Günther; HIGA JÚNIOR, Minoru German; GONTIJO, Célia Maria Ferreira; PEREIRA, Agnes Antônia Sampaio; DORVAL, Maria Elizabeth Moraes C.

    2016-01-01

    Cutaneous leishmaniasis is caused by different species of theLeishmania genus. Leishmania(Leishmania) infantum, causing cutaneous leishmaniasis, has been described in patients living in areas where visceral leishmaniasis is endemic. In this study, it was possible to characterize this species in seven slides from cutaneous tissue imprints from patients with cutaneous leishmaniasis in the State of Mato Grosso do Sul, Brazil.

  9. Th1 Cell Development Induced by Cysteine Proteinases A and B in Localized Cutaneous Leishmaniasis Due to Leishmania guyanensis

    Science.gov (United States)

    Pascalis, Hervé; Lavergne, Anne; Bourreau, Eliane; Prévot-Linguet, Ghislaine; Kariminia, Amina; Pradinaud, Roger; Rafati, Sima; Launois, Pascal

    2003-01-01

    The cysteine proteinases CPA and CPB from Leishmania major induced Th1 responses in patients with leishmaniasis due to Leishmania guyanensis. Furthermore, cysteine proteinases induced neither interleukin 4 (IL-4) nor IL-13 and low levels of IL-10 in controls and patients. The results suggest that CPs would be quite good candidates for a vaccine against different Leishmania species. PMID:12704171

  10. Leishmania Surveillance and Diagnostic Capability in Support of the Joint Biological Agent Identification and Diagnostic System (JBAIDS) and Leishmania Vector Surveillance

    Science.gov (United States)

    2013-02-07

    01-10-09 to 07-02-13 ’+. I II L~ J.\\NU :::OU~ Ill L~ :la. l-UI’I I 11J.\\l- I NUIVI~~I1 LEISHMANIA SURVEILLANCE AND DIAGNOSTIC CAPABILITY IN None...SUPPORT OF THE JOINT BIOLOGICAL AGENT IDENTIFICATION AND :lD. l:JI1J.\\NI NUIVI~~I1 DIAGNOSTIC SYSTEM (JBAIDS) None . ./ LEISHMANIA VECTOR...Field Station at Kisumu completed project activities through a resource sharing arrangement with the 59th MDW. Testing of the Leishmania epidemiology

  11. Oral effectiveness of PMIC4, a novel hydroxyethylpiperazine analogue, in Leishmania amazonensis

    Directory of Open Access Journals (Sweden)

    Mariela Ferreira de Vasconcelos

    2014-12-01

    Full Text Available Pentavalent antimonials have saved the lives of thousands of Leishmania-infected patients more than seventy years but, unfortunately, they are highly toxic and require parenteral delivery. Therefore, the search for safer and orally delivered alternative is a need. This paper describes the antileishmanial properties of PMIC4, a novel hydroxyethylpiperazine analogue. PMIC4 showed potent activity against intracellular amastigotes of Leishmania amazonensis, with IC50 of 1.8 μM and selectivity index higher than 100-fold, calculated in relation to the toxicity on the host cell. Following laboratory animal welfare policies, we analyzed the absorption, distribution, metabolism, excretion and toxicity (ADMET properties and calculated the Lipinski’s rule of five of PMIC4 before proceeding to in vivo tests. PMIC4 satisfied Lipinski’s rule of five and presented high probability of human intestinal absorption, suggesting a good chance of druglikeness and oral bioavailability. For in vivo studies, PMIC4 was administered via intralesional injection (3.4 mg/kg/day, three times a week or orally (34.0 mg/kg/day, five times a week to L. amazonensis-infected BALB/c mice throughout the 98 day experiments. At the end of the treatment period, serum markers of toxicity were measured. When administered orally, PMIC4 controlled the lesions in L. amazonensis-infected BALB/c mice without altering serological markers of toxicity. These results demonstrate that PMIC4 is a promising molecular scaffold, orally effective against experimental leishmaniasis.

  12. MicroRNA expression profile in human macrophages in response to Leishmania major infection.

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    Julien Lemaire

    Full Text Available Leishmania (L. are intracellular protozoan parasites able to survive and replicate in the hostile phagolysosomal environment of infected macrophages. They cause leishmaniasis, a heterogeneous group of worldwide-distributed affections, representing a paradigm of neglected diseases that are mainly embedded in impoverished populations. To establish successful infection and ensure their own survival, Leishmania have developed sophisticated strategies to subvert the host macrophage responses. Despite a wealth of gained crucial information, these strategies still remain poorly understood. MicroRNAs (miRNAs, an evolutionarily conserved class of endogenous 22-nucleotide non-coding RNAs, are described to participate in the regulation of almost every cellular process investigated so far. They regulate the expression of target genes both at the levels of mRNA stability and translation; changes in their expression have a profound effect on their target transcripts.We report in this study a comprehensive analysis of miRNA expression profiles in L. major-infected human primary macrophages of three healthy donors assessed at different time-points post-infection (three to 24 h. We show that expression of 64 out of 365 analyzed miRNAs was consistently deregulated upon infection with the same trends in all donors. Among these, several are known to be induced by TLR-dependent responses. GO enrichment analysis of experimentally validated miRNA-targeted genes revealed that several pathways and molecular functions were disturbed upon parasite infection. Finally, following parasite infection, miR-210 abundance was enhanced in HIF-1α-dependent manner, though it did not contribute to inhibiting anti-apoptotic pathways through pro-apoptotic caspase-3 regulation.Our data suggest that alteration in miRNA levels likely plays an important role in regulating macrophage functions following L. major infection. These results could contribute to better understanding of the

  13. Clinical and laboratory alterations in dogs naturally infected by Leishmania chagasi

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    José Cláudio Carneiro de Freitas

    2012-02-01

    Full Text Available INTRODUCTION: Canine visceral leishmaniasis (CVL is a zoonotic disease with different clinical manifestations. Parasitism often occurs in bone marrow, but changes have been observed in peripheral blood and serum biochemical parameters. The aim of this study was to evaluate the hematological and biochemical parameters in dogs naturally infected by Leishmania chagasi. METHODS: Eighty-five adult dogs of both sexes and various weights and ages from the Zoonosis Control Center of Fortaleza (CCZ were used, selected by immunofluorescence assay (IFA and considered positive with IFA titers greater than 1:40 and by visualizing amastigotes of Leishmania chagasi in smears obtained by bone marrow aspiration. The dogs (n = 85 were grouped according to clinical signs: negative (CN = 7, subclinical (CS = 10, and clinical (CC = 68. Blood samples were collected for determination of hematological and biochemical serum values. The experimental protocol was approved by the CEUA/UECE. RESULTS: The most frequent clinical signs were cachexia (77.9%, keratitis (61.8%, and lymphadenopathy (55.9%, and 86.8% of the animals showed more than one clinical sign characteristic of CVL. In CC were observed reductions in red blood cells (63%, hematocrit (72%, and hemoglobin (62%, as well as leukocytosis (33%, neutropenia (28%, thrombocytopenia (50%, uremia (45%, hyperproteinemia (53%, p<0.05, hypergammaglobulinemia (62%, p<0.01, and hypoalbuminemia (58%. CONCLUSIONS: Animals with the clinical form of the disease demonstrate hematological and biochemical changes consistent with anemia, uremia, hyperproteinemia, and hyperglobulinemia, which present themselves as strong clinical markers of visceral leishmaniasis associated with the signs previously reported.

  14. Enhanced protective efficacy of nonpathogenic recombinant leishmania tarentolae expressing cysteine proteinases combined with a sand fly salivary antigen.

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    Zahedifard, Farnaz; Gholami, Elham; Taheri, Tahereh; Taslimi, Yasaman; Doustdari, Fatemeh; Seyed, Negar; Torkashvand, Fatemeh; Meneses, Claudio; Papadopoulou, Barbara; Kamhawi, Shaden; Valenzuela, Jesus G; Rafati, Sima

    2014-03-01

    Novel vaccination approaches are needed to prevent leishmaniasis. Live attenuated vaccines are the gold standard for protection against intracellular pathogens such as Leishmania and there have been new developments in this field. The nonpathogenic to humans lizard protozoan parasite, Leishmania (L) tarentolae, has been used effectively as a vaccine platform against visceral leishmaniasis in experimental animal models. Correspondingly, pre-exposure to sand fly saliva or immunization with a salivary protein has been shown to protect mice against cutaneous leishmaniasis. Here, we tested the efficacy of a novel combination of established protective parasite antigens expressed by L. tarentolae together with a sand fly salivary antigen as a vaccine strategy against L. major infection. The immunogenicity and protective efficacy of different DNA/Live and Live/Live prime-boost vaccination modalities with live recombinant L. tarentolae stably expressing cysteine proteinases (type I and II, CPA/CPB) and PpSP15, an immunogenic salivary protein from Phlebotomus papatasi, a natural vector of L. major, were tested both in susceptible BALB/c and resistant C57BL/6 mice. Both humoral and cellular immune responses were assessed before challenge and at 3 and 10 weeks after Leishmania infection. In both strains of mice, the strongest protective effect was observed when priming with PpSP15 DNA and boosting with PpSP15 DNA and live recombinant L. tarentolae stably expressing cysteine proteinase genes. The present study is the first to use a combination of recombinant L. tarentolae with a sand fly salivary antigen (PpSP15) and represents a novel promising vaccination approach against leishmaniasis.

  15. Canine Leishmania vaccines: still a long way to go.

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    Gradoni, Luigi

    2015-02-28

    Dogs are the main reservoir host for zoonotic visceral leishmaniasis, a sand fly-borne disease caused by Leishmania infantum. In endemic areas, "susceptible" dogs suffer from a severe disease characterized by chronic polymorphic viscerocutaneous signs that manifest several months from the exposure, whereas "resistant" dogs can remain subclinically infected for years or lifelong. The protective immune response to Leishmania is cell-mediated; for visceralizing Leishmania species a mixed T helper (Th)1/Th2 response with a dominant Th1 profile is required for protection. The activation of the adaptive immune system in naturally resistant dogs is revealed by parasite-specific lymphoproliferation, delayed-type hypersensitivity, the production of interferon-γ and tumour necrosis factor-α cytokines, and enhanced macrophage leishmanicidal activity via nitric oxide. Hence, an effective canine Leishmania vaccine should induce strong and long-lasting Th1-dominated immunity to control both infection progression and the parasite transmissibility via the vector. Preclinical research in rodent models has evaluated the efficacy of several categories of Leishmania antigens including killed parasites, cell purified fractions, parasite protein components or subunits, single or multiple chimeric recombinant proteins, plasmid DNA and viral particles encoding parasite virulence factors. Promising antigen(s)/adjuvant combinations from each of the above categories have also been tested in dogs; they mostly resulted in limited or no protection in Phase I-II studies (designed to test vaccine safety, immunogenicity and laboratory-induced protection) in which vaccinated dogs were challenged by the artificial intravenous injection of high-load L. infantum promastigotes. The recombinant A2 antigen plus saponin conferred about 40% protection against infection by this challenge system and has been registered in Brazil as a canine vaccine (LeishTec(®)). An increasing number of efficacy studies

  16. Toxoplasma gondii, Neospora caninum and Leishmania spp. serology and Leishmania spp. PCR in dogs from Pirassununga, SP

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    Nathália Mendonça de Seabra

    Full Text Available Abstract We examined the presence of antibodies against the parasites Toxoplasma gondii, Neospora caninum, and Leishmania spp., as well the presence of DNA from Leishmania spp., in dogs from Pirassununga - SP. The seropositivity rate was compared with the animals’ originating location. Three hundred seventy-three blood samples from the county’s kennel and local veterinary clinics were collected and analyzed. A total of 300 samples were tested for T. gondii and N. caninum using an indirect immunofluorescence antibody test (IFAT; 45% (135/300 were positive for T. gondii and 24.3% (73/300 were positive for N. caninum. Three hundred seventy-three samples were tested for Leishmania spp. using the IFAT. Of these, 4.6% (17/373 were positive. Additionally, 145 samples were tested using a polymerase chain reaction (PCR; of these samples, 0.7% (1/145 was positive. Considering the results, we conclude that these parasites are present in the city of Pirassununga - SP and that the animals have contact with the protozoan. It is therefore necessary to create methods for disease prevention to maintain both animal and human health in regard to leishmaniasis and toxoplasmosis.

  17. In vivo and in vitro phagocytosis of Leishmania (Leishmania) amazonensis promastigotes by B-1 cells.

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    Geraldo, M M; Costa, C R; Barbosa, F M C; Vivanco, B C; Gonzaga, W F K M; Novaes E Brito, R R; Popi, A F; Lopes, J D; Xander, P

    2016-06-01

    Leishmaniasis is caused by Leishmania parasites that infect several cell types. The promastigote stage of Leishmania is internalized by phagocytic cells and transformed into the obligate intracellular amastigote form. B-1 cells are a subpopulation of B cells that are able to differentiate in vitro and in vivo into mononuclear phagocyte-like cells with phagocytic properties. B-1 cells use several receptors for phagocytosis, such as the mannose receptor and third complement receptor. Leishmania binds to the same receptors on macrophages. In this study, we demonstrated that phagocytes derived from B-1 cells (B-1 CDP) were able to internalize promastigotes of L. (L.) amazonensis in vitro. The internalized promastigotes differentiated into amastigotes. Our results showed that the phagocytic index was higher in B-1 CDP compared to peritoneal macrophages and bone marrow-derived macrophages. The in vivo phagocytic ability of B-1 cells was also demonstrated. Parasites were detected inside purified B-1 cells after intraperitoneal infection with L. (L.) amazonensis promastigotes. Intraperitoneal stimulation with the parasites led to an increase in both IL-10 and TNF-α. These results highlight the importance of studying B-1 CDP cells as phagocytic cells that can participate and contribute to immunity to parasites. © 2016 John Wiley & Sons Ltd.

  18. Natural infection of phlebotomines (Diptera: Psychodidae) by Leishmania (Leishmania) amazonensis in an area of ecotourism in Central-Western Brazil.

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    Brilhante, Andreia Fernandes; Nunes, Vânia Lúcia Brandão; Kohatsu, Kleber Augusto; Galati, Eunice Aparecida Bianchi; Rocca, Maria Elizabeth Ghizzi; Ishikawa, Edna Aoba Yassui

    2015-01-01

    Bonito municipality, known as an area of ecoturism, in Mato Grosso do Sul state, Brazil, is also a focus of visceral and cutaneous leishmaniases, with cases registered in both human and canine populations. This study sought to investigate natural infection by flagellate forms of Leishmania in phlebotomines of the urban area of Bonito. Sand flies were collected fortnightly from October 2005 to July 2006 with modified automatic light traps installed in peridomiciles and animal shelters in the center and on the outskirts of the city. The females were dissected and their guts observed under an optical microscope. A total of 1977 specimens were captured, Lutzomyia longipalpis (88.4 %) and Bichromomyia flaviscutelata (3.0 %) being the most frequent species. Bi. flaviscutellata was found infected by flagellates that were identified as Leishmania (Leishmania) amazonensis by indirect immunofluorescence reaction, employing monoclonal antibodies and the biotin-avidin system. This is the first report of natural infection by L. amazonensis in Bi. flaviscutellata in a Brazilian urban area. As Bi. flaviscutellata is only slightly attracted by humans, the transmission of L. amazonensis in the study area may have a zoonotic character; however, the sympatric occurrence of this parasite and Lu. longipalpis should be taken into consideration by the local health authorities since this sand fly has already been found with L. amazonensis DNA in a focus of canine visceral leishmaniasis in Bonito municipality.

  19. Biodistribution of meglumine antimoniate in healthy and Leishmania (Leishmania infantum chagasi-infected BALB/c mice

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    Samanta Etel Treiger Borborema

    2013-08-01

    Full Text Available Pentavalent antimonials such as meglumine antimoniate (MA are the primary treatments for leishmaniasis, a complex disease caused by protozoan parasites of the genus Leishmania . Despite over 70 years of clinical use, their mechanisms of action, toxicity and pharmacokinetics have not been fully elucidated. Radiotracer studies performed on animals have the potential to play a major role in pharmaceutical development. The aims of this study were to prepare an antimony radiotracer by neutron irradiation of MA and to determine the biodistribution of MA in healthy and Leishmania (Leishmania infantum chagasi-infected mice. MA (Glucantime(r was neutron irradiated inside the IEA-R1 nuclear reactor, producing two radioisotopes, 122Sb and 124Sb, with high radionuclidic purity and good specific activity. This irradiated compound presented anti-leishmanial activity similar to that of non-irradiated MA in both in vitro and in vivo evaluations. In the biodistribution studies, healthy mice showed higher uptake of antimony in the liver than infected mice and elimination occurred primarily through biliary excretion, with a small proportion of the drug excreted by the kidneys. The serum kinetic curve was bi-exponential, with two compartments: the central compartment and another compartment associated with drug excretion. Radiotracers, which can be easily produced by neutron irradiation, were demonstrated to be an interesting tool for answering several questions regarding antimonial pharmacokinetics and chemotherapy.

  20. Leishmania (Leishmania mexicana en el corregimiento de San Matías, municipio de Gómez Plata, Antioquia, Colombia

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    Diana Sierra

    2006-10-01

    Full Text Available Introducción. La leishmaniaisis es una enfermedad encontrada en focos naturales de infección donde están presentes insectos vectores y mamíferos reservorios deLeishmania. Objetivo. Registrar por primera vez la presencia de Leishmania (Leishmania mexicana Biagi, 1953, en el corregimiento de San Matías, municipio de Gómez Plata, departamento de Antioquia. Materiales y métodos. La especie fue aislada de un paciente con leishmaniasis cutánea localizada e identificada por la técnica de Inmunofluorescencia utilizando anticuerpos monoclonales específicos de especie y electroforesis de enzimas . Resultados y conclusión. Su perfil isoenzimático similar al de las cepas de referencia L. (L. mexicana (MNCY/BZ/62/M379 y L. (L. mexicana (MHOM/BE/82/BEL21, permitió concluír que la especie aislada del paciente es L. (L. mexicana.

  1. [Isoenzymatic characterization of human isolates of Leishmania sp (Kinetoplastida: Trypanosomatidae) from the municipalities of Rio Preto da Eva and Manaus, State of Amazonas].

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    Figueira, Luanda de Paula; Zanotti, Michele; Pinheiro, Francimeire Gomes; Franco, Antonia Maria Ramos

    2008-01-01

    Twenty-three isolates of Leishmania sp from patients in the municipalities of Rio Preto da Eva and Manaus were characterized and identified by means of isoenzyme electrophoresis and the degree of similarity between the organisms was analyzed. The results indicated that Leishmania guyanensis and Leishmania naiffi were present in these two environments and that the Leishmania naiffi samples were heterogenous.

  2. Molecular and serological detection of Leishmania spp. in captive wild animals from Ilha Solteira, SP, Brazil.

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    Jusi, Márcia Mariza Gomes; Starke-Buzetti, Wilma Aparecida; Oliveira, Trícia Maria Ferreira de Sousa; Tenório, Michely da Silva; Sousa, Lúcio de Oliveira de; Machado, Rosangela Zacarias

    2011-01-01

    Leishmaniasis is a zoonotic disease that affects 12 million people worldwide. Several mammalian species can serve as a reservoir for this disease. Dogs are the main reservoir for visceral leishmaniasis in urban areas, which has become a serious public health concern in Brazil. The aim of this study was to evaluate the presence of Leishmania spp. in captive wild animals from Ilha Solteira, São Paulo, Brazil. Blood and various tissues samples were collected from animals of five different species: Speothos venaticus, Chrysocyon brachyurus, Cerdocyon thous, Pseudalopex vetulus, and Procyon cancrivorus. Antibodies against Leishmania spp. were detected in three wild canids by indirect fluorescent antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA). PCR analyses of blood and bone marrow from all animals were negative, but Leishmania DNA was found in the tissues and skin of seropositive animals. Positive PCR samples were also positive for Leishmania donovani complex. Analysis of sequenced PCR products showed similarities with different regions of Leishmania (Leishmania) infantum and Leishmania (Leishmania) chagasi kinetoplastids. Measures to control visceral leishmaniasis in wild animals kept in Brazilian zoos should be established, as no disease control programs are currently available.

  3. Leishmaniasis in Turkey: Visceral and cutaneous leishmaniasis caused by Leishmania donovani in Turkey

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    Özbilgin, Ahmet; Harman, Mehmet; Karakuş, Mehmet; Bart, Aldert; Töz, Seray; Kurt, Özgür; Çavuş, İbrahim; Polat, Erdal; Gündüz, Cumhur; van Gool, Tom; Özbel, Yusuf

    2017-01-01

    In Turkey, the main causative agents are Leishmania tropica (L. tropica) and Leishmania infantum (L. infantum) for cutaneous leishmaniasis (CL) and L. infantum for visceral leishmaniasis (VL). In this study, we investigated leishmaniasis cases caused by L. donovani and established animal models for

  4. A proteogenomic approach to map the proteome of an unsequenced pathogen - Leishmania donovani.

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    Pawar, H.; Sahasrabuddhe, N.A.; Renuse, S.; Keerthikumar, S.; Sharma, J.; Kumar, G.S.; Venugopal, A.; Sekhar, N.R.; Kelkar, D.S.; Nemade, H.; Khobragade, S.N.; Muthusamy, B.; Kandasamy, K.; Harsha, H.C.; Chaerkady, R.; Patole, M.S.; Pandey, A.

    2012-01-01

    Visceral leishmaniasis or kala azar is the most severe form of leishmaniasis and is caused by the protozoan parasite Leishmania donovani. There is no published report on L. donovani genome sequence available till date, although the genome sequences of three related Leishmania species are already

  5. Molecular Identification of Leishmania spp. in Sand Flies (Diptera: Psychodidae, Phlebotominae) From Ecuador.

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    Quiroga, Cristina; Cevallos, Varsovia; Morales, Diego; Baldeón, Manuel E; Cárdenas, Paúl; Rojas-Silva, Patricio; Ponce, Patricio

    2017-11-07

    The detection and identification of natural infections in sand flies by Leishmania protozoan species in endemic areas is a key factor in assessing the risk of leishmaniasis and in designing prevention and control measures for this infectious disease. In this study, we analyzed the Leishmania DNA using nuclear ribosomal internal transcript spacer (ITS) sequences. Parasite DNA was extracted from naturally infected, blood-fed sand flies collected in nine localities considered leishmaniasis-endemic foci in Ecuador.The species of parasites identified in sand flies were Leishmania major-like, Leishmania naiffi, Leishmania mexicana, Leishmania lainsoni, and "Leishmania sp. siamensis". Sand fly specimens of Brumptomyia leopoldoi, Mycropigomyia cayennensis, Nyssomyia yuilli yuilli, Nyssomyia trapidoi, Pressatia triacantha, Pressatia dysponeta, Psychodopygus carrerai carrerai, Psychodopygus panamensis, and Trichophoromyia ubiquitalis were found positive for Leishmania parasite. These findings contribute to a better understanding of the epidemiology and transmission dynamics of the disease in high-risk areas of Ecuador. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

  6. Surveillance for antibodies to Leishmania spp. in dogs from Sri Lanka and India

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    The global distribution of leishmaniasis is rapidly expanding into new geographic regions. Dogs are the primary reservoir hosts for human visceral leishmaniasis (VL) caused by infection with Leishmania infantum. Natural infections with other Leishmania species can occur in dogs, but their role as re...

  7. Serological and molecular survey of Leishmania infection in dogs from Luanda, Angola

    NARCIS (Netherlands)

    Vilhena, Hugo; Granada, Sara; Oliveira, Ana Cristina; Schallig, Henk D. F. H.; Nachum-Biala, Yaarit; Cardoso, Luís; Baneth, Gad

    2014-01-01

    Canine leishmaniosis (CanL) due to Leishmania infantum is a global zoonosis endemic in more than 70 countries in Europe, North Africa, Asia and America; however, data on this infection is scarce from southern Africa. The aim of this study was to survey dogs in Luanda, Angola, for Leishmania

  8. Anticorpos antipeptídeos citrulinados e fator reumatoide em pacientes sudaneses com infecção por Leishmania donovani Anti-citrullinated peptide antibodies and rheumatoid factor in Sudanese patients with Leishmania donovani infection

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    Erik Ahlin

    2011-12-01

    Full Text Available OBJETIVO: Este estudo avaliou a presença de anticorpos antipeptídeos citrulinados cíclicos (anti-CCP, fator reumatoide (FR e imunocomplexos circulantes (ICC em pacientes sudaneses infectados por Leishmania donovani. PACIENTES E MÉTODOS: Os soros foram coletados de pacientes infectados por Leishmania (n = 116 e de sudaneses saudáveis (n = 93. Dezenove pacientes sudaneses com artrite reumatoide (AR e anti-CCP+ foram incluídos como controles positivos. Os níveis de ICC e anti-CCP foram medidos por ELISA. Para avaliar a reatividade citrulina-específica foi usada a placa-controle com peptídeos-controle cíclicos contendo arginina em vez de citrulina. RESULTADOS: Entre os pacientes infectados por Leishmania e os pacientes com AR e anti-CCP+, a maioria (86% era positiva para FR, enquanto a frequência de positividade para ICC foi maior entre pacientes com leishmaniose visceral (LV (LV 38%; AR e anti-CCP+ 24%. Quando foi analisada a reatividade anti-CCP, 12% dos pacientes com LV foram positivos. Os níveis de anti-CCP entre os pacientes com LV correlacionaram-se bem com os níveis de ICC encontrados (r = 0,65; P OBJECTIVE: The present study evaluated the presence of anti-cyclic citrullinated peptides antibodies (anti-CCP, rheumatoid factor (RF, and circulating immune complexes (CIC in Sudanese patients infected with the Leishmania donovani parasite. PATIENTS AND METHODS: Sera were collected from Leishmania infected patients (n = 116 and healthy Sudanese (n = 93. Nineteen Sudanese anti-CCP+ RA patients were included as positive controls. Levels of CIC and anti-CCP were measured by ELISA. Control plate with cyclic control peptides containing arginine instead of citrulline was used to evaluate citrulline specifi c reactivity. RESULTS: Among Leishmania-infected patients and anti-CCP+ RA patients, most were RF positive (86%, while the frequency of CIC positivity was higher among visceral leishmaniasis (VL patients (VL 38%; anti-CCP+ RA 24%. When

  9. Differential Recruitment of Dendritic Cells Subsets to Lymph Nodes Correlates with a Protective or Permissive T-Cell Response during Leishmania (Viannia) Braziliensis or Leishmania (Leishmania) Amazonensis Infection.

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    Carvalho, A K; Carvalho, K; Passero, L F D; Sousa, M G T; da Matta, V L R; Gomes, C M C; Corbett, C E P; Kallas, G E; Silveira, F T; Laurenti, M D

    2016-01-01

    Leishmania (L.) amazonensis (La) and L. (V.) braziliensis (Lb) are responsible for a large clinical and immunopathological spectrum in human disease; while La may be responsible for anergic disease, Lb infection leads to cellular hypersensitivity. To better understand the dichotomy in the immune response caused by these Leishmania species, we evaluated subsets of dendritic cells (DCs) and T lymphocyte in draining lymph nodes during the course of La and Lb infection in BALB/c mice. Our results demonstrated a high involvement of DCs in La infection, which was characterized by the greater accumulation of Langerhans cells (LCs); conversely, Lb infection led to an increase in dermal DCs (dDCs) throughout the infection. Considering the T lymphocyte response, an increase of effector, activated, and memory CD4(+) T-cells was observed in Lb infection. Interleukin- (IL-) 4- and IL-10-producing CD4(+)and CD8(+) T-cells were present in both La and Lb infection; however, interferon- (IFN-) γ-producing CD4(+)and CD8(+) T-cells were detected only in Lb infection. The results suggest that during Lb infection, the dDCs were the predominant subset of DCs that in turn was associated with the development of Th1 immune response; in contrast La infection was associated with a preferential accumulation of LCs and total blockage of the development of Th1 immune response.

  10. Leishmania amazonensis and Leishmania chagasi: In vitro leishmanicide activity of Virola surinamensis (rol.) warb.

    Science.gov (United States)

    Veiga, Andreza; Albuquerque, Kelly; Corrêa, Maria Elinete; Brigido, Helliton; Silva E Silva, João; Campos, Marliane; Silveira, Fernando; Santos, Lourivaldo; Dolabela, Maria

    2017-04-01

    Virola species have been used in traditional medicine as healing in skin infections. From V. surinanensis oil were isolated several sesquiterpene as the nerolidol which showed activity against species of Leishmania. The current study aimed to evaluate the leishmanicide activity and toxicity of extracts, fractions and surinamesin obtained from leaves of Virola surinamensis. Hexane, Ethyl Acetate, and Methanol extracts were obtained from powder of dry leaves of V. surinamensis. The hexane and ethyl acetate extracts were fractionated by silica gel column chromatography and increasingly polar gradient. The viability of L. chagasi and L. amazonensis promastigotes was assessed by tetrazolium salt assay (MTT). Peritoneal macrophages were exposed to L. amazonensis promastigotes. The treatment was performed with the extracts for 24 h. Then, the coverslips were stained and the infection index was determined. Cytotoxicity was determined in macrophage cells by peritoneum viability assay (MTT). The selectivity index was calculated as the product of cytotoxic concentration 50% and inhibitory concentration 50%. The hexane extract showed leishmanicide activity in promastigotes. The ethyl acetate, methanol extracts and fractions (C1-C6), were inactive against promastigote form of L. chagasi and L. amzazonensis. None extract showed effect on L. amazonensis amastigotes. All samples tested showed low cytotoxicity (CC50 > 500 μg/mL). The selectivity index of the hexane extract was greater than 5. The hexane extract of V. surinamensis was active against L. chagasi and L. amazonensis promastigotes. The extract fractionation did not increase significantly its antipromastigote activity. The surinamensin is probably not responsible for the activity. The extracts were inactive against amastigotes of L. amazonensis. Copyright © 2017. Published by Elsevier Inc.

  11. Severity of tegumentary leishmaniasis is not exclusively associated with Leishmania RNA virus 1 infection in Brazil

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    Luiza de Oliveira Ramos Pereira

    2013-08-01

    Full Text Available Leishmania RNA virus (LRV has been shown to be a symbiotic component of Leishmania parasites in South America. Nested retro-transcription polymerase chain reaction was employed to investigate LRV1 presence in leishmaniasis lesions from Brazil. In endemic areas of Rio de Janeiro (RJ, no LRV1 infection was observed even with mucosal involvement. LRV1 was only detected in Leishmania (V. guyanensis cutaneous lesions from the northern region, which were obtained from patients presenting with disease reactivation after clinical cure of their primary lesions. Our results indicated that the severity of leishmaniasis in some areas of RJ, where Leishmania (V. brazi-liensis is the primary etiological agent, was not associated with Leishmania LRV1 infection.

  12. Characterization of Leishmania spp. causing cutaneous leishmaniasis in Manaus, Amazonas, Brazil.

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    Camara Coelho, Leila Ines; Paes, Marcilene; Guerra, Jorge Augusto; Barbosa, Maria das Graças; Coelho, Candisse; Lima, Bruna; Brito, Maria Edileuza; Brandão Filho, Sinval Pinto

    2011-03-01

    In the State of Amazonas, American tegumentary leishmaniasis is endemic and presents a wide spectrum of clinical variability due to the large diversity of circulating species in the region. Isolates from patients in Manaus and its metropolitan region were characterized using monoclonal antibodies and isoenzymes belonging to four species of the parasite: Leishmania (Viannia) guyanensis, 73% (153/209); Leishmania (Viannia) braziliensis, 14% (30/209); Leishmania (Leishmania) amazonensis, 8% (17/209); and Leishmania (Viannia) naiffii, 4% (9/209). The most prevalent species was L. (V.) guyanensis. The principal finding of this study was the important quantity of infections involving more than one parasite species, representing 14% (29/209) of the total. The findings obtained in this work regarding the parasite are further highlighted by the fact that these isolates were obtained from clinical samples collected from single lesions.

  13. Presence of antibodies against Leishmania spp. in domestic dogs from Toledo, Paraná, Brazil

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    Lucas André Ludwig

    2016-10-01

    Full Text Available Leishmaniases are a group of diseases caused by Leishmania protozoa affecting various vertebrate hosts, including humans and dogs. Dogs represent the most important domestic reservoir of leishmaniasis. For this reason, the aim of this study was to detect the presence of antibodies against Leishmania spp. in dogs being treated at the veterinary hospital of our institution. Samples were obtained from 175 animals by jugular or cephalic venipuncture, and serum was subsequently separated. Anti-Leishmania spp. IgG antibodies were detected in these specimens using indirect immunofluorescence. This revealed that of the 175 serum samples, those of four (2.28% animals reacted positively and the antibodies title was 40. These data are consistent with the transmission of Leishmania spp. in the region, suggesting that dogs represent a reservoir of American cutaneous leishmaniasis. This is the first description of circulating antibodies against Leishmania spp. in the West region of Paraná State.

  14. Anti-Leishmania activity of new ruthenium(II) complexes: Effect on parasite-host interaction.

    Science.gov (United States)

    Costa, Mônica S; Gonçalves, Yasmim G; Nunes, Débora C O; Napolitano, Danielle R; Maia, Pedro I S; Rodrigues, Renata S; Rodrigues, Veridiana M; Von Poelhsitz, Gustavo; Yoneyama, Kelly A G

    2017-10-01

    Leishmaniasis is a parasitic disease caused by protozoa of the genus Leishmania. The many complications presented by the current treatment - including high toxicity, high cost and parasite resistance - make the development of new therapeutic agents indispensable. The present study aims to evaluate the anti-Leishmania potential of new ruthenium(II) complexes, cis‑[RuII(η2-O2CR)(dppm)2]PF6, with dppm=bis(diphenylphosphino)methane and R=4-butylbenzoate (bbato) 1, 4-(methylthio)benzoate (mtbato) 2 and 3-hydroxy-4-methoxybenzoate (hmxbato) 3, in promastigote cytotoxicity and their effect on parasite-host interaction. The cytotoxicity of complexes was analyzed by MTT assay against Leishmania (Leishmania) amazonensis, Leishmania (Viannia) braziliensis, Leishmania (Leishmania) infantum promastigotes and the murine macrophage (RAW 264.7). The effect of complexes on parasite-host interaction was evaluated by in vitro infectivity assay performed in the presence of two different concentrations of each complex: the promastigote IC50 value and the concentration nontoxic to 90% of RAW 264.7 macrophages. Complexes 1-3 exhibited potent cytotoxic activity against all Leishmania species assayed. The IC50 values ranged from 7.52-12.59μM (complex 1); 0.70-3.28μM (complex 2) and 0.52-1.75μM (complex 3). All complexes significantly inhibited the infectivity index at both tested concentrations. The infectivity inhibitions ranged from 37 to 85%. Interestingly, the infectivity inhibitions due to complex action did not differ significantly at either of the tested concentrations, except for the complex 1 against Leishmania (Leishmania) infantum. The infectivity inhibitions resulted from reductions in both percentage of infected macrophages and number of parasites per macrophage. Taken together the results suggest remarkable leishmanicidal activity in vitro by these new ruthenium(II) complexes. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Biomarkers of safety and immune protection for genetically modified live attenuated leishmania vaccines against visceral leishmaniasis - discovery and implications.

    Science.gov (United States)

    Gannavaram, Sreenivas; Dey, Ranadhir; Avishek, Kumar; Selvapandiyan, Angamuthu; Salotra, Poonam; Nakhasi, Hira L

    2014-01-01

    Despite intense efforts there is no safe and efficacious vaccine against visceral leishmaniasis, which is fatal and endemic in many tropical countries. A major shortcoming in the vaccine development against blood-borne parasitic agents such as Leishmania is the inadequate predictive power of the early immune responses mounted in the host against the experimental vaccines. Often immune correlates derived from in-bred animal models do not yield immune markers of protection that can be readily extrapolated to humans. The limited efficacy of vaccines based on DNA, subunit, heat killed parasites has led to the realization that acquisition of durable immunity against the protozoan parasites requires a controlled infection with a live attenuated organism. Recent success of irradiated malaria parasites as a vaccine candidate further strengthens this approach to vaccination. We developed several gene deletion mutants in Leishmania donovani as potential live attenuated vaccines and reported extensively on the immunogenicity of LdCentrin1 deleted mutant in mice, hamsters, and dogs. Additional limited studies using genetically modified live attenuated Leishmania parasites as vaccine candidates have been reported. However, for the live attenuated parasite vaccines, the primary barrier against widespread use remains the absence of clear biomarkers associated with protection and safety. Recent studies in evaluation of vaccines, e.g., influenza and yellow fever vaccines, using systems biology tools demonstrated the power of such strategies in understanding the immunological mechanisms that underpin a protective phenotype. Applying similar tools in isolated human tissues such as PBMCs from healthy individuals infected with live attenuated parasites such as LdCen(-/-) in vitro followed by human microarray hybridization experiments will enable us to understand how early vaccine-induced gene expression profiles and the associated immune responses are coordinately regulated in normal

  16. Biomarkers of Safety and Immune Protection for Genetically Modified Live Attenuated Leishmania Vaccines Against Visceral Leishmaniasis – Discovery and Implications

    Science.gov (United States)

    Gannavaram, Sreenivas; Dey, Ranadhir; Avishek, Kumar; Selvapandiyan, Angamuthu; Salotra, Poonam; Nakhasi, Hira L.

    2014-01-01

    Despite intense efforts there is no safe and efficacious vaccine against visceral leishmaniasis, which is fatal and endemic in many tropical countries. A major shortcoming in the vaccine development against blood-borne parasitic agents such as Leishmania is the inadequate predictive power of the early immune responses mounted in the host against the experimental vaccines. Often immune correlates derived from in-bred animal models do not yield immune markers of protection that can be readily extrapolated to humans. The limited efficacy of vaccines based on DNA, subunit, heat killed parasites has led to the realization that acquisition of durable immunity against the protozoan parasites requires a controlled infection with a live attenuated organism. Recent success of irradiated malaria parasites as a vaccine candidate further strengthens this approach to vaccination. We developed several gene deletion mutants in Leishmania donovani as potential live attenuated vaccines and reported extensively on the immunogenicity of LdCentrin1 deleted mutant in mice, hamsters, and dogs. Additional limited studies using genetically modified live attenuated Leishmania parasites as vaccine candidates have been reported. However, for the live attenuated parasite vaccines, the primary barrier against widespread use remains the absence of clear biomarkers associated with protection and safety. Recent studies in evaluation of vaccines, e.g., influenza and yellow fever vaccines, using systems biology tools demonstrated the power of such strategies in understanding the immunological mechanisms that underpin a protective phenotype. Applying similar tools in isolated human tissues such as PBMCs from healthy individuals infected with live attenuated parasites such as LdCen−/− in vitro followed by human microarray hybridization experiments will enable us to understand how early vaccine-induced gene expression profiles and the associated immune responses are coordinately regulated in normal

  17. Leishmania amazonensis amastigotes highly express a tryparedoxin peroxidase isoform that increases parasite resistance to macrophage antimicrobial defenses and fosters parasite virulence.

    Science.gov (United States)

    Henard, Calvin A; Carlsen, Eric D; Hay, Christie; Kima, Peter E; Soong, Lynn

    2014-07-01

    Professional phagocytes generate a myriad of antimicrobial molecules to kill invading microorganisms, of which nitrogen oxides are integral in controlling the obligate intracellular pathogen Leishmania. Although reactive nitrogen species produced by the inducible nitric oxide synthase (iNOS) can promote the clearance of intracellular parasites, some Leishmania species/stages are relatively resistant to iNOS-mediated antimicrobial activity. The underlying mechanism for this resistance remains largely uncharacterized. Here, we show that the amastigote form of L. amazonensis is hyper-resistant to the antimicrobial actions of cytokine-activated murine and human macrophages as compared to its promastigote counterpart. Amastigotes exhibit a marked ability to directly counter the cytotoxicity of peroxynitrite (ONOO-), a leishmanicidal oxidant that is generated during infection through the combined enzymatic activities of NADPH oxidase and iNOS. The enhanced antinitrosative defense of amastigotes correlates with the increased expression of a tryparedoxin peroxidase (TXNPx) isoform that is also upregulated in response to iNOS enzymatic activity within infected macrophages. Accordingly, ectopic over-expression of the TXNPx isoform by L. amazonensis promastigotes significantly enhances parasite resistance against ONOO- cytotoxicity. Moreover, TXNPx-overexpressing parasites exhibit greater intra-macrophage survival, and increased parasite growth and lesion development in a murine model of leishmaniasis. Our investigations indicate that TXNPx isoforms contribute to Leishmania's ability to adapt to and antagonize the hostile microenvironment of cytokine-activated macrophages, and provide a mechanistic explanation for persistent infection in experimental and human leishmaniasis.

  18. Leishmania amazonensis amastigotes highly express a tryparedoxin peroxidase isoform that increases parasite resistance to macrophage antimicrobial defenses and fosters parasite virulence.

    Directory of Open Access Journals (Sweden)

    Calvin A Henard

    2014-07-01

    Full Text Available Professional phagocytes generate a myriad of antimicrobial molecules to kill invading microorganisms, of which nitrogen oxides are integral in controlling the obligate intracellular pathogen Leishmania. Although reactive nitrogen species produced by the inducible nitric oxide synthase (iNOS can promote the clearance of intracellular parasites, some Leishmania species/stages are relatively resistant to iNOS-mediated antimicrobial activity. The underlying mechanism for this resistance remains largely uncharacterized. Here, we show that the amastigote form of L. amazonensis is hyper-resistant to the antimicrobial actions of cytokine-activated murine and human macrophages as compared to its promastigote counterpart. Amastigotes exhibit a marked ability to directly counter the cytotoxicity of peroxynitrite (ONOO-, a leishmanicidal oxidant that is generated during infection through the combined enzymatic activities of NADPH oxidase and iNOS. The enhanced antinitrosative defense of amastigotes correlates with the increased expression of a tryparedoxin peroxidase (TXNPx isoform that is also upregulated in response to iNOS enzymatic activity within infected macrophages. Accordingly, ectopic over-expression of the TXNPx isoform by L. amazonensis promastigotes significantly enhances parasite resistance against ONOO- cytotoxicity. Moreover, TXNPx-overexpressing parasites exhibit greater intra-macrophage survival, and increased parasite growth and lesion development in a murine model of leishmaniasis. Our investigations indicate that TXNPx isoforms contribute to Leishmania's ability to adapt to and antagonize the hostile microenvironment of cytokine-activated macrophages, and provide a mechanistic explanation for persistent infection in experimental and human leishmaniasis.

  19. Factores dermicos que condicionan la infeccion de Lutzomyia townsendi (Ortiz, 1959 por Leishmania spp. de Venezuela Dermal factors which condition infection of Lutzomyia townsendi (Ortiz, 1959 by Leishmania spp. of Venezuela

    Directory of Open Access Journals (Sweden)

    Maritza Carnevali

    1982-12-01

    Full Text Available Se estudia la susceptibilidad de Lutzomyia townsendi a la infección con Leishmania spp. sobre lesiones experimentales de hamsteres. Se estudia la frecuencia y distribución de los amastigotos en la dermis, relacionándola con la profundidad que alcanza el estilete bucal del insecto. Una correlación positiva, con significante coeficiente de correlación, se establece entre la frecuencia de los parásitos a una profundidad de 100-150 nm en la dermis y el éxito de la infección de los flebótomos.The susceptibility of Lutzomyia townsendi to infection with amastigotes of Leishmania spp. from experimental lesions in hamsters is studied. A good correlation is found when the number of infected sandflies are compared with the distribution and density of parasites in the dermis, taking into account the size of the fascicle, particularly the length of labrun and dental depth in maxillae. Considerations are made on the susceptibilities of some anthropophilic sandflies from America that are considered as good vectors.

  20. Sand fly captures with Disney traps in area of occurrence of Leishmania (Leishmania) amazonensis in the state of Mato Grosso do Sul, mid-western Brazil.

    Science.gov (United States)

    Dorval, Maria Elizabeth Cavalheiros; Alves, Tulia Peixoto; Cristaldo, Geucira; Rocha, Hilda Carlos da; Alves, Murilo Andrade; Oshiro, Elisa Teruya; Oliveira, Alessandra Gutierrez de; Brazil, Reginaldo Peçanha; Galati, Eunice Aparecida Bianchi; Cunha, Rivaldo Venancio da

    2010-01-01

    The work was conducted to study phlebotomine fauna (Diptera: Psychodidae) and aspects of American cutaneous leishmaniasis transmission in a forested area where Leishmania (Leishmania) amazonensis occurs, situated in the municipality of Bela Vista, State of Mato Grosso do Sul, Brazil. The captures were conducted with modified Disney traps, using hamster (Mesocricetus auratus) as bait, from May 2004 to January 2006. Ten species of phlebotomine sandflies were captured: Brumptomyia avellari, Brumptomyia brumpti, Bichromomyia flaviscutellata, Evandromyia bourrouli, Evandromyia lenti, Lutzomyia longipalpis, Psathyromyia campograndensis, Psathyromyia punctigeniculata, Psathyromyia shannoni and Sciopemyia sordellii. The two predominant species were Ev bourrouli (57.3%) and Bi flaviscutellata (41.4%), present at all sampling sites. Two of the 36 hamsters used as bait presented natural infection with Leishmania. The parasite was identified as Leishmania (Leishmania) amazonensis. Analysis of the results revealed the efficiency of Disney traps for capturing Bichromomyia flaviscutellata and the simultaneous presence of both vector and the Leishmania species transmitted by the same can be considered a predictive factor of the occurrence of leishmaniasis outbreaks for the human population that occupies the location.

  1. Characterization of Leishmania (Leishmania) waltoni n.sp. (Kinetoplastida: Trypanosomatidae), the Parasite Responsible for Diffuse Cutaneous Leishmaniasis in the Dominican Republic.

    Science.gov (United States)

    Shaw, Jeffrey; Pratlong, Francine; Floeter-Winter, Lucile; Ishikawa, Edna; El Baidouri, Fouad; Ravel, Christophe; Dedet, Jean-Pierre

    2015-09-01

    Leishmania parasites isolated, between 1979 and 1988 by the late Bryce Walton, from Dominican Republic (DR) patients with diffuse cutaneous leishmaniasis, were characterized using a panel of 12 isoenzymes, 23 monoclonal antibodies, small subunit ribosomal DNA (SSu rDNA), and multilocus sequence analysis (MLSA). The isoenzyme and monoclonal antibody profiles and the MLSA results showed that the Dominican Republic parasites were distinct from other described Leishmania species. This new species belongs to the mexicana complex, which is distributed in central and parts of northern South America. It is suggested that the parasites uniqueness from other members of the mexicana complex is related to it being isolated on an island for millions of years. If Leishmania (Leishmania) waltoni fails to adapt to some imported mammal, such as the house rat, it will be the only Leishmania to be classified as an endangered species. The excessive destruction of habitats on Hispaniola threatens the survival of its vectors and presumed natural reservoirs, such as the rodent hutias and the small insectivorous mammal solenodon. The concept of Leishmania species is discussed in the light of recent evaluations on criteria for defining bacterial species. © The American Society of Tropical Medicine and Hygiene.

  2. Antibiotic resistance free plasmid DNA expressing LACK protein leads towards a protective Th1 response against Leishmania infantum infection.

    Science.gov (United States)

    Ramos, I; Alonso, A; Peris, A; Marcen, J M; Abengozar, M A; Alcolea, P J; Castillo, J A; Larraga, V

    2009-11-12

    Canine visceral leishmaniasis is a serious public health concern in the Mediterranean basin since dogs are the main Leishmania infantum reservoir. However, there is not a vaccination method in veterinary use in this area, and therefore the development of a vaccine against this parasite is essential for the possible control of the disease. Previous reports have shown the efficacy of heterologous prime-boost vaccination with the pCIneo plasmid and the poxvirus VV (both Western Reserve and MVA strains) expressing L. infantum LACK antigen against canine leishmaniasis. As pCIneo-LACK plasmid contains antibiotic resistance genes, its use as a profilactic method is not recommended. Hence, the antibiotic resistance gene free pORT-LACK plasmid is a more suitable tool for its use as a vaccine. Here we report the protective and immunostimulatory effect of the prime-boost pORT-LACK/MVA-LACK vaccination tested in a canine experimental model. Vaccination induced a reduction in clinical signs and in parasite burden in the liver, an induction of the Leishmania-specific T cell activation, as well as an increase of the expression of Th1 type cytokines in PBMC and target organs.

  3. Leishmania infantum-induced primary and challenge infections in rhesus monkeys (Macaca mulatta): a primate model for visceral leishmaniasis.

    Science.gov (United States)

    Porrozzi, R; Pereira, M S; Teva, A; Volpini, A C; Pinto, M A; Marchevsky, R S; Barbosa, A A; Grimaldi, G

    2006-10-01

    Visceral leishmaniasis (VL) was experimentally induced in rhesus macaques (Macaca mulatta) by intravenously inoculating 2 x 10(7)amastigotes/kg of body weight of Leishmania infantum. The macaques developed a systemic disease showing characteristic features of human VL such as fever, diarrhoea, body weight loss, anaemia, hypergammaglobulinaemia and transient lymphocytosis, as well as lymph node, liver and/or spleen enlargement. Nine weeks after infection, one primate showed pronounced weight loss, became moribund and was euthanized. The necropsy findings included granulomas composed of parasite-containing macrophages, lymphocytes and plasma cells in the liver, spleen and lymph nodes. The remaining macaques had a sustained course of infection but developed a mild-to-moderate illness that subsequently showed evidence of self-cure. Of note, pathological findings included a typical cell-mediated immunity-induced granulomatous reaction that had an effect on the control of parasite replication. All infected monkeys responded with increased production of anti-Leishmania-specific IgG antibodies. Despite the fact that clinical resistance to L. infantum was not consistently associated with a parasite-specific cell-mediated immune response, drug-cured macaques from the primary infection acquired immunity to homologous re-infection. These findings point to the feasibility of using the L. infantum macaque model for pre-clinical evaluation of novel chemotherapeutics or vaccine candidates for human VL.

  4. In Vivo Selection of Paromomycin and Miltefosine Resistance in Leishmania donovani and L. infantum in a Syrian Hamster Model.

    Science.gov (United States)

    Hendrickx, S; Mondelaers, A; Eberhardt, E; Delputte, P; Cos, P; Maes, L

    2015-08-01

    In 2002 and 2006, respectively, miltefosine (MIL) and paromomycin (PMM) were licensed in the Indian subcontinent for treatment of visceral leishmaniasis; however, their future routine use might become jeopardized by the development of drug resistance. Although experimental selection of resistant strains in vitro has repeatedly been reported using the less relevant promastigote vector stage, the outcome of resistance selection on intracellular amastigotes was reported to be protocol and species dependent. To corroborate these in vitro findings, selection of resistance in Leishmania donovani and Leishmania infantum was achieved by successive treatment/relapse cycles in infected Syrian golden hamsters. For PMM, resistant amastigotes were already obtained within 3 treatment/relapse cycles, while their promastigotes retained full susceptibility, thereby sharing the same phenotypic characteristics as in vitro-generated PMM-resistant strains. For MIL, even five treatment/relapse cycles failed to induce significant susceptibility changes in either species, which also corresponds with the in vitro observations where selection of an MIL-resistant phenotype proved to be quite challenging. In conclusion, these results argue for cautious use of PMM in the field to avoid rapid emergence of primary resistance and highlight the need for additional research on the mechanisms and dynamics of MIL resistance selection. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  5. Characterization of the B cell response to Leishmania infection after anti-CD20 B cell depletion.

    Science.gov (United States)

    Bockenstedt, Marie M; Boggiatto, Paola M; Jones, Douglas E

    2015-01-01

    Anti-CD20 depletion therapies targeting B cells are commonly used in malignant B cell disease and autoimmune diseases. There are concerns about the ability of B cells to respond to infectious diseases acquired either before or after B cell depletion. There is evidence that the B cell response to existing or acquired viral infections is compromised during treatment, as well as the antibody response to vaccination. Our laboratory has an experimental system using co-infection of C3H mice with both Leishmania major and Leishmania amazonensis that suggests that the B cell response is important to healing infected mice. We tested if anti-CD20 treatment would completely restrict the B cell response to these intracellular pathogens. Infected mice that received anti-CD20 B cell depletion therapy had a significant decrease in CD19(+) cells within their lymph nodes and spleens. However, splenic B cells were detected in depleted mice and an antigen-specific antibody response was produced. These results indicate that an antigen-specific B cell response towards intracellular pathogens can be generated during anti-CD20 depletion therapy.

  6. Real-time PCR for Leishmania species identification: Evaluation and comparison with classical techniques.

    Science.gov (United States)

    de Morais, Rayana Carla Silva; da Costa Oliveira, Cintia Nascimento; de Albuquerque, Suênia da Cunha Gonçalves; Mendonça Trajano Silva, Lays Adrianne; Pessoa-E-Silva, Rômulo; Alves da Cruz, Heidi Lacerda; de Brito, Maria Edileuza Felinto; de Paiva Cavalcanti, Milena

    2016-06-01

    Cutaneous leishmaniasis (CL) is a parasitic disease caused by various Leishmania species. Several studies have shown that real time quantitative PCR (qPCR) can be used for Leishmania spp. identification by analyzing the melting temperature (Tm). Thus, the aim of this study was to evaluate the viability of qPCR for differentiating eight closely related Leishmania species that cause the same clinical form of the disease and to compare the results with classical techniques. qPCR assays for standardizing the Tm using reference strains were performed. After the CL diagnosis on blood samples of domestic animals, positive samples were analyzed by their Tm and qPCR products were purified and sequenced. Ten human samples previously characterized by Multilocus Enzyme Electrophoresis (MLEE) were also analyzed by Tm. A Restriction Fragment Length Polymorphism (RFLP) assay, a reference test, was also standardized, by using the reference strains. Through standardization of Tm for Leishmania spp., two Tm ranges were created for analysis: 1 (Tm = 78-79.99 °C) included Leishmania (V.) braziliensis, Leishmania (V.) panamensis, Leishmania (V.) lainsoni, Leishmania (V.) guyanensis and Leishmania (V.) shawi; and 2 (Tm = 80-82.2 °C) included Leishmania (V.) naiffi, Leishmania (L.) amazonensis and Leishmania (L.) mexicana. A total of 223 positive blood samples were analyzed, with 58 included in range 1 and 165 in range 2. L. (V.) braziliensis, L. (V.) panamensis and L. (V.) guyanensis were identified by sequencing, while L. (V.) braziliensis, L. (L.) mexicana and L. (V.) panamensis were identified by RFLP analysis. Ten human samples previously characterized by Multilocus Enzyme Electrophoresis (MLEE) were also analyzed by qPCR Tm analysis; five were classified in range 1 and five in range 2. A concordance of 80% was calculated between qPCR and the gold-standard (MLEE) with no significant difference between the methods (p = 0.6499); a similar result was observed for sequencing

  7. Differentiation of Leishmania species by FT-IR spectroscopy

    Science.gov (United States)

    Aguiar, Josafá C.; Mittmann, Josane; Ferreira, Isabelle; Ferreira-Strixino, Juliana; Raniero, Leandro

    2015-05-01

    Leishmaniasis is a parasitic infectious disease caused by protozoa that belong to the genus Leishmania. It is transmitted by the bite of an infected female Sand fly. The disease is endemic in 88 countries Desjeux (2001) [1] (16 developed countries and 72 developing countries) on four continents. In Brazil, epidemiological data show the disease is present in all Brazilian regions, with the highest incidences in the North and Northeast. There are several methods used to diagnose leishmaniasis, but these procedures have many limitations, are time consuming, have low sensitivity, and are expensive. In this context, Fourier Transform Infrared Spectroscopy (FT-IR) analysis has the potential to provide rapid results and may be adapted for a clinical test with high sensitivity and specificity. In this work, FT-IR was used as a tool to investigate the promastigotes of Leishmaniaamazonensis, Leishmaniachagasi, and Leishmaniamajor species. The spectra were analyzed by cluster analysis and deconvolution procedure base on spectra second derivatives. Results: cluster analysis found four specific regions that are able to identify the Leishmania species. The dendrogram representation clearly indicates the heterogeneity among Leishmania species. The band deconvolution done by the curve fitting in these regions quantitatively differentiated the polysaccharides, amide III, phospholipids, proteins, and nucleic acids. L. chagasi and L. major showed a greater biochemistry similarity and have three bands that were not registered in L. amazonensis. The L. amazonensis presented three specific bands that were not recorded in the other two species. It is evident that the FT-IR method is an indispensable tool to discriminate these parasites. The high sensitivity and specificity of this technique opens up the possibilities for further studies about characterization of other microorganisms.

  8. Subversion and Utilization of Host Innate Defense by Leishmania amazonensis.

    Science.gov (United States)

    Soong, Lynn

    2012-01-01

    Infection with Leishmania amazonensis and other members of the Leishmania mexicana complex can lead to diverse clinical manifestations, some of which are relatively difficult to control, even with standard chemotherapy. Diffuse cutaneous leishmaniasis (CL) is a rare but severe form, and its clinical hallmark is excessive parasitic growth in infected cells accompanied by profound impairments in host immune responses to the parasites. Since these parasites also cause non-healing CL in most inbred strains of mice, these animals are valuable models for dissecting the mechanisms of persistent infection and disease pathogenesis. In comparison to other Leishmania species, L. amazonensis infections are most remarkable for their ability to repress the activation and effector functions of macrophages, dendritic cells, and CD4(+) T cells, implying discrete mechanisms at work. In addition to this multilateral suppression of host innate and adaptive immunity, the activation of types I and II interferon-mediated responses and autophagic/lipid metabolic pathways actually promotes rather than restrains L. amazonensis infection. These seemingly contradictory findings reflect the remarkable adaptation of the parasites to the ancient defense machinery of the host, as well as the complex parasite-host interactions at different stages of infection, which collectively contribute to non-healing leishmaniasis in the New World. This review article highlights new evidence that reveals the strategies utilized by L. amazonensis parasites to subvert or modulate host innate defense machinery in neutrophils and macrophages, as well as the regulatory roles of host innate responses in promoting parasite survival and replication within the huge parasitophorous vacuoles. A better understanding of unique features in host responses to these parasites at early and late stages of infection is important for the rational design of control strategies for non-healing leishmaniasis.

  9. Interaction of avirulent Leishmania species with rat peritoneal macrophages

    Directory of Open Access Journals (Sweden)

    Trina Bastardo

    1983-03-01

    Full Text Available An "in vitro" system has been developed for study of host cell-parasite interaction in visceral and cutaneous leishmaniasis. Avirulent promastigotes of L. brasiliensis and L. donovani, from strains originally isolated from human cases and mantained by serial culture in Davis' Medium were allowed to infect cultured macrophages from rat peritoneal exudate. Challenge of the macrophages by parasites took place in 199 medium, at 33ºC for L. brasiliensis and at 37ºC for L. donovani. Although the rat is resistant to infections by Leishmania spp., the promastigotes not only invaded the host cells, but transformed into amastigotes and later mutiplied, from 10 min after challenge to 24 hours later.Um sistema "in vivo" foi desenvolvido para estudar-se o comportamento do parasito-célula hospedeiro em leshimaniose cutânea e visceral com promastigotos avirulentos de L. brasiliensis e L. donovani (mantidos no meio Davis e com macrófagos de exsudado peritonial de rato. As espécies inicialmente foram isoladas de casos humanos. A confrontação de Leishmania spp-macrófago se realizou na presença do meio 199 e a duas temperaturas diferentes, para L. brasiliensis 33ºC e para L donovani 37ºC. Apesar de o rato ser um animal resistente à infecção de Leishmania spp.; promastigotos das espécies por nos estudadas não só se interiorizaram mas também se diferenciaram em amastigotos com posterior multiplicação, a partir dos 10 minutos depois da infecção dos macrófagos e até as 24 horas.

  10. Glucantime resistant Leishmania promastigotes are sensitive to pentostam

    Directory of Open Access Journals (Sweden)

    Elizabeth Spangler Andrade Moreira

    1992-12-01

    Full Text Available Growth inhibition in vitro tests were used to study the susceptibility to pentostam of different Leishmania strains involved in cutaneous and mucocutaneos leishmaniasis - one glucantime sensitive strain, three naturally glucantime resistant strains and one glucantime resistant line developed by in vitro drug exposure. Contrasting with the high degree , of glucantime resistance, all strains were sensitive to pentostam. These differences suggest that there is some relationship between chemical structure and in vitro activity for these antimonial compounds. These data justify a clinical re-evaluation to compare therapeutic efficacy of glucantime and pentostam in the treatment of leishmaniasis.

  11. Studies on the effectiveness of diarylheptanoids derivatives against Leishmania amazonensis

    Directory of Open Access Journals (Sweden)

    Catarina AC Araujo

    1999-11-01

    Full Text Available In a previous work we demonstrated that diarylheptanoids extracted from Centrolobium sclerophyllum are very active against Leishmania amazonensis promastigotes. In order to continue our studies with these class of compounds, we decided to evaluate the activity of several diarylheptanoids derived from curcumin (diferuloyl methane against the extracellular form (promastigotes of L. amazonensis. Furthermore, an experiment against the intracellular form of the parasite (amastigotes was carried out, comparing the most active compound among the curcumin derivatives (the methylcurcumin with des-O-methylcentrolobine, the most active diarylheptanoid derived from C. sclerophyllum.

  12. Studies on the effectiveness of diarylheptanoids derivatives against Leishmania amazonensis.

    Science.gov (United States)

    Araujo, C A; Alegrio, L V; Gomes, D C; Lima, M E; Gomes-Cardoso, L; Leon, L L

    1999-01-01

    In a previous work we demonstrated that diarylheptanoids extracted from Centrolobium sclerophyllum are very active against Leishmania amazonensis promastigotes. In order to continue our studies with these class of compounds, we decided to evaluate the activity of several diarylheptanoids derived from curcumin (diferuloyl methane) against the extracellular form (promastigotes) of L. amazonensis. Furthermore, an experiment against the intracellular form of the parasite (amastigotes) was carried out, comparing the most active compound among the curcumin derivatives (the methylcurcumin) with des-O-methylcentrolobine, the most active diarylheptanoid derived from C. sclerophyllum.

  13. Analysis of kinetoplast cytochrome b gene of 16 Leishmania isolates from different foci of China: different species of Leishmania in China and their phylogenetic inference

    Science.gov (United States)

    2013-01-01

    Background Leishmania species belong to the family Trypanosomatidae and cause leishmaniasis, a geographically widespread disease that infects humans and other vertebrates. This disease remains endemic in China. Due to the large geographic area and complex ecological environment, the taxonomic position and phylogenetic relationship of Chinese Leishmania isolates remain uncertain. A recent internal transcribed spacer 1 and cytochrome oxidase II phylogeny of Chinese Leishmania isolates has challenged some aspects of their traditional taxonomy as well as cladistics hypotheses of their phylogeny. The current study was designed to provide further disease background and sequence analysis. Methods We systematically analyzed 50 cytochrome b (cyt b) gene sequences of 19 isolates (16 from China, 3 from other countries) sequenced after polymerase chain reaction (PCR) using a special primer for cyt b as well as 31 sequences downloaded from GenBank. After alignment, the data were analyzed using the maximum parsimony, Bayesian and netwok methods. Results Sequences of six haplotypes representing 10 Chinese isolates formed a monophyletic group and clustered with Leishmania tarentolae. The isolates GS1, GS7, XJ771 of this study from China clustered with other isolates of Leishmania donovani complex. The isolate JS1 was a sister to Leishmania tropica, which represented an L. tropica complex instead of clustering with L. donovani complex or with the other 10 Chinese isolates. The isolates KXG-2 and GS-GER20 formed a monophyletic group with Leishmania turanica from central Asia. In the different phylogenetic trees, all of the Chinese isolates occurred in at least four groups regardless of geographic distribution. Conclusions The undescribed Leishmania species of China, which are clearly causative agents of canine leishmaniasis and human visceral leishmaniasis and are related to Sauroleishmania, may have evolved from a common ancestral parasite that came from the Americas and may have

  14. Dermotropic Leishmania donovani in Sri Lanka: visceralizing potential in clinical and preclinical studies.

    Science.gov (United States)

    Kariyawasam, K K G D U L; Selvapandiyan, A; Siriwardana, H V Y D; Dube, A; Karunanayake, P; Senanayake, S A S C; Dey, R; Gannavaram, S; Nakhasi, H L; Karunaweera, N D

    2017-11-08

    The visceralizing potential of apparently dermotropic Leishmania donovani in Sri Lanka (L. donovani-SL) was investigated through long-term follow-up of cutaneous leishmaniasis (CL) patients and in vivo and in vitro experimental infection models. CL patients (n = 250) treated effectively with intra-lesional antimony therapy were followed-up six monthly for 4 years. There was no clinical evidence of visceralization of infection (VL) during this period. Infection of BALB/c mice with L. donovani-SL (test) through intra-dermal route led to the development of cutaneous lesions at the site of inoculation with no signs of systemic dissemination, in contrast to the observations made in animals similarly infected with a visceralizing strain of L. donovani-1S (control). Cytokine (IL-10, IFN-γ) release patterns of splenocytes and lymph node cell cultures derived from mice primed with experimental infections (with either test or control parasites) revealed significantly high IFN-γ response associated with test mice with CL, while prominent IL-10 levels were observed in association with control mice with VL. Furthermore, diminished infection efficiency, intracellular growth and survival of L. donovani-SL parasites compared with L. donovani-1S were evident through in vitro macrophage infection experiments. These studies confirm, for the first time, the essential dermotropic nature of L. donovani-SL suggesting natural attenuation of virulence of local parasite strains.

  15. Inflammasome-derived IL-1β production induces nitric oxide-mediated resistance to Leishmania.

    Science.gov (United States)

    Lima-Junior, Djalma S; Costa, Diego L; Carregaro, Vanessa; Cunha, Larissa D; Silva, Alexandre L N; Mineo, Tiago W P; Gutierrez, Fredy R S; Bellio, Maria; Bortoluci, Karina R; Flavell, Richard A; Bozza, Marcelo T; Silva, João S; Zamboni, Dario S

    2013-07-01

    Parasites of the Leishmania genus are the causative agents of leishmaniasis in humans, a disease that affects more than 12 million people worldwide. These parasites replicate intracellularly in macrophages, and the primary mechanisms underlying host resistance involve the production of nitric oxide (NO). In this study we show that the Nlrp3 inflammasome is activated in response to Leishmania infection and is important for the restriction of parasite replication both in macrophages and in vivo as demonstrated through the infection of inflammasome-deficient mice with Leishmania amazonensis, Leishmania braziliensis and Leishmania infantum chagasi. Inflammasome-driven interleukin-1β (IL-1β) production facilitated host resistance to infection, as signaling through IL-1 receptor (IL-1R) and MyD88 was necessary and sufficient to trigger inducible nitric oxide synthase (NOS2)-mediated production of NO. In this manuscript we identify a major signaling platform for host resistance to Leishmania spp. infection and describe the molecular mechanisms underlying Leishmania-induced NO production.

  16. Phylogenetic position of Leishmania isolates from Khyber Pakhtunkhwa province of Pakistan.

    Science.gov (United States)

    Khan, Nazma Habib; Messenger, Louisa A; Wahid, Sobia; Sutherland, Colin J

    2016-08-01

    Several species of the genus Leishmania are causative agents of cutaneous leishmaniasis in Pakistan. This study aimed to determine phylogenetic placement of Leishmania species causing cutaneous leishmaniasis in Khyber Pakhtunkhwa province, Pakistan (34 Leishmania tropica, 3 Leishmania infantum), in-relation to species from other geographical areas using gene sequences encoding cytochrome b (cytb) and internal transcribed spacer 2 (its2). Based on cytochrome b sequence analysis, L. tropica strains from Pakistan and other geographical regions were differentiated into two genotype groups, A and B. Within the province, five distinct L. tropica genotypes were recognized; two in group A, three in group B. Two L. infantum isolates from the province were closely associated with both Afro-Eurasian and American species of the Leishmania donovani complex, including Leishmania chagasi, L. infantum and L. donovani from Sudan and Ethiopia; while a third L. infantum isolate could not be differentiated from visceralizing Kenyan and Indian L. donovani. We observed apposite phylogenetic placement of CL-causing L. tropica and L. infantum from Khyber Pakhtunkhwa. Affinities ascribed to Leishmania spp. From the region are valuable in tracing potential importation of leishmaniasis. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  17. Genome-wide mapping reveals single-origin chromosome replication in Leishmania, a eukaryotic microbe.

    Science.gov (United States)

    Marques, Catarina A; Dickens, Nicholas J; Paape, Daniel; Campbell, Samantha J; McCulloch, Richard

    2015-10-19

    DNA replication initiates on defined genome sites, termed origins. Origin usage appears to follow common rules in the eukaryotic organisms examined to date: all chromosomes are replicated from multiple origins, which display variations in firing efficiency and are selected from a larger pool of potential origins. To ask if these features of DNA replication are true of all eukaryotes, we describe genome-wide origin mapping in the parasite Leishmania. Origin mapping in Leishmania suggests a striking divergence in origin usage relative to characterized eukaryotes, since each chromosome appears to be replicated from a single origin. By comparing two species of Leishmania, we find evidence that such origin singularity is maintained in the face of chromosome fusion or fission events during evolution. Mapping Leishmania origins suggests that all origins fire with equal efficiency, and that the genomic sites occupied by origins differ from related non-origins sites. Finally, we provide evidence that origin location in Leishmania displays striking conservation with Trypanosoma brucei, despite the latter parasite replicating its chromosomes from multiple, variable strength origins. The demonstration of chromosome replication for a single origin in Leishmania, a microbial eukaryote, has implications for the evolution of origin multiplicity and associated controls, and may explain the pervasive aneuploidy that characterizes Leishmania chromosome architecture.

  18. First molecular detection of Leishmania tarentolae-like DNA in Sergentomyia minuta in Spain.

    Science.gov (United States)

    Bravo-Barriga, Daniel; Parreira, Ricardo; Maia, Carla; Blanco-Ciudad, Juan; Afonso, Maria Odete; Frontera, Eva; Campino, Lenea; Pérez-Martín, Juan Enrique; Serrano Aguilera, Francisco Javier; Reina, David

    2016-03-01

    Phlebotomine sand flies (Diptera, Psychodidae) are vectors of multiple Leishmania species, among which Leishmania infantum stands out as a being frequently pathogenic to humans and dogs in Mediterranean countries. In this study, Sergentomyia minuta sand flies were collected using CDC miniature light traps in different 431 biotopes from Southwest Spain. A total of 114 females were tested for the presence of Leishmania DNA by targeting ITS-1 and cyt-B sequences by PCR. Leishmania DNA was detected in one S. minuta. Characterization of the obtained DNA sequences by phylogenetic analyses revealed close relatedness with Leishmania tarentolae Wenyon, 1921 as well as with both human and canine pathogenic strains of Asian origin (China), previously described as Leishmania sp. To our knowledge, this is the first report of phlebotomine sand flies naturally infected with L. tarentolae-like in Spain. The possible infection of sand flies with novel Leishmania species should be taken into consideration in epidemiological studies of vector species in areas where leishmaniosis is endemic.

  19. Screening for subclinical Leishmania infection in HIV-infected patients living in eastern Spain.

    Science.gov (United States)

    Ena, Javier; Pasquau, Francisco; del Mar López-Perezagua, María; Martinez-Peinado, Carmen; Arjona, Francisco

    2014-12-01

    We anticipated that patients with HIV infection living in endemic areas were at greater risk of infection which can reactivate due to immunosuppression; therefore, we analyzed the prevalence of latent Leishmania infantum infection in patients infected with HIV. A total of 179 patients with HIV infection were screened for the presence of anti-Leishmania antibodies using indirect immunofluorescent antibody test (IFAT) (Leishmania-spot IF; bioMérieux, Marcy l'Etoile, France). All patients were followed up for at least 1 year. The primary end-point was to confirm the presence of Leishmania infection. Significant titer of antibodies to Leishmania was detected in six (3%; 95% confidence interval: 0.5-5.5%) asymptomatic patients. Two of them had visceral leishmaniasis that was confirmed by parasite visualization in clinical samples, the presence of Leishmania promastigotes in Novy-MacNeal-Nicolle culture, polymerase chain reaction (PCR)-based methods, and/or urinary antigen test. Among 173 patients with indirect immunofluorescent antibody test below 1:40, one HIV-infected patient severely immunosuppressed, confirmed negative by IFAT, was diagnosed of visceral leishmaniasis. The use of indirect immunofluorescent antibody test for Leishmania screening is not justified in asymptomatic patients with HIV infection living in endemic areas due to the small rate of significant antibody titer and the low frequency of clinical disease.

  20. Functional Characterization of Monomeric GTPase Rab1 in the Secretory Pathway of Leishmania.

    Science.gov (United States)

    Bahl, Surbhi; Parashar, Smriti; Malhotra, Himanshu; Raje, Manoj; Mukhopadhyay, Amitabha

    2015-12-11

    Leishmania secretes a large number of its effectors to the extracellular milieu. However, regulation of the secretory pathway in Leishmania is not well characterized. Here, we report the cloning, expression, and characterization of the Rab1 homologue from Leishmania. We have found that LdRab1 localizes in Golgi in Leishmania. To understand the role of LdRab1 in the secretory pathway of Leishmania, we have generated transgenic parasites overexpressing GFP-LdRab1:WT, GFP-LdRab1:Q67L (a GTPase-deficient dominant positive mutant of Rab1), and GFP-LdRab1:S22N (a GDP-locked dominant negative mutant of Rab1). Surprisingly, our results have shown that overexpression of GFP-LdRab1:Q67L or GFP-LdRab1:S22N does not disrupt the trafficking and localization of hemoglobin receptor in Leishmania. To determine whether the Rab1-dependent secretory pathway is conserved in parasites, we have analyzed the role of LdRab1 in the secretion of secretory acid phosphatase and Ldgp63 in Leishmania. Our results have shown that overexpression of GFP-LdRab1:Q67L or GFP-LdRab1:S22N significantly inhibits the secretion of secretory acid phosphatase by Leishmania. We have also found that overexpression of GFP-LdRab1:Q67L or GFP-LdRab1:S22N retains RFP-Ldgp63 in Golgi and blocks the secretion of Ldgp63, whereas the trafficking of RFP-Ldgp63 in GFP-LdRab1:WT-expressing cells is unaltered in comparison with control cells. Taken together, our results have shown that the Rab1-regulated secretory pathway is well conserved, and hemoglobin receptor trafficking follows an Rab1-independent secretory pathway in Leishmania. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. First detection of Leishmania spp. DNA in Brazilian bats captured strictly in urban areas.

    Science.gov (United States)

    de Oliveira, Fernanda Müller; Costa, Luis Henrique Camargo; de Barros, Thainá Landim; Ito, Pier Kenji Rauschkolb Katsuda; Colombo, Fábio Antonio; de Carvalho, Cristiano; Pedro, Wagner André; Queiroz, Luzia Helena; Nunes, Cáris Maroni

    2015-10-01

    Leishmania spp. is a protozoan that maintains its life cycle in domestic and wild animals and it may include bats, a population that has increased in urban environments. This study aimed to investigate the presence of Leishmania spp. in bats captured strictly in urban areas that are endemic for visceral leishmaniasis. The spleen and skin samples of 488 bats from 21 endemic cities in northwestern São Paulo State, Brazil, were tested for the presence of Leishmania kDNA using real-time PCR. Differentiation from Trypanosoma spp. was achieved by amplifying a DNA fragment of the ribosomal RNA gene. The presence of Leishmania spp. kDNA was verified in 23.9% of bats and Trypanosoma spp. DNA was identified in 3.9%. Leishmania species differentiation revealed the presence of Leishmania amazonensis in 78.3% of the bats; L. infantum in 17.4%, and 1 sample (4.3%) showed a mix pattern of L. infantum and L. amazonensis. We also detected, for the first time, L. infantum and L. amazonensis DNA in Desmodus rotundus, the hematophagous bat. The presence of Leishmania spp. DNA in bats strictly from urban areas endemic for visceral leishmaniasis in the State of São Paulo, Brazil indicates that these wild and abundant animals are capable of harboring Leishmania spp. in this new scenario. Due to their longevity, high dispersion capacity and adaptability to synanthropic environments, they may play a role in the maintenance of the life cycle of Leishmania parasites. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Functional Characterization of Monomeric GTPase Rab1 in the Secretory Pathway of Leishmania*

    Science.gov (United States)

    Bahl, Surbhi; Parashar, Smriti; Malhotra, Himanshu; Raje, Manoj; Mukhopadhyay, Amitabha

    2015-01-01

    Leishmania secretes a large number of its effectors to the extracellular milieu. However, regulation of the secretory pathway in Leishmania is not well characterized. Here, we report the cloning, expression, and characterization of the Rab1 homologue from Leishmania. We have found that LdRab1 localizes in Golgi in Leishmania. To understand the role of LdRab1 in the secretory pathway of Leishmania, we have generated transgenic parasites overexpressing GFP-LdRab1:WT, GFP-LdRab1:Q67L (a GTPase-deficient dominant positive mutant of Rab1), and GFP-LdRab1:S22N (a GDP-locked dominant negative mutant of Rab1). Surprisingly, our results have shown that overexpression of GFP-LdRab1:Q67L or GFP-LdRab1:S22N does not disrupt the trafficking and localization of hemoglobin receptor in Leishmania. To determine whether the Rab1-dependent secretory pathway is conserved in parasites, we have analyzed the role of LdRab1 in the secretion of secretory acid phosphatase and Ldgp63 in Leishmania. Our results have shown that overexpression of GFP-LdRab1:Q67L or GFP-LdRab1:S22N significantly inhibits the secretion of secretory acid phosphatase by Leishmania. We have also found that overexpression of GFP-LdRab1:Q67L or GFP-LdRab1:S22N retains RFP-Ldgp63 in Golgi and blocks the secretion of Ldgp63, whereas the trafficking of RFP-Ldgp63 in GFP-LdRab1:WT-expressing cells is unaltered in comparison with control cells. Taken together, our results have shown that the Rab1-regulated secretory pathway is well conserved, and hemoglobin receptor trafficking follows an Rab1-independent secretory pathway in Leishmania. PMID:26499792

  3. The flagellar protein FLAG1/SMP1 is a candidate for Leishmania-sand fly interaction.

    Science.gov (United States)

    Di-Blasi, Tatiana; Lobo, Amanda R; Nascimento, Luanda M; Córdova-Rojas, Jose L; Pestana, Karen; Marín-Villa, Marcel; Tempone, Antonio J; Telleria, Erich L; Ramalho-Ortigão, Marcelo; McMahon-Pratt, Diane; Traub-Csekö, Yara M

    2015-03-01

    Leishmaniasis is a serious problem that affects mostly poor countries. Various species of Leishmania are the agents of the disease, which take different clinical manifestations. The parasite is transmitted by sandflies, predominantly from the Phlebotomus genus in the Old World and Lutzomyia in the New World. During development in the gut, Leishmania must survive various challenges, which include avoiding being expelled with blood remnants after digestion. It is believed that attachment to the gut epithelium is a necessary step for vector infection, and molecules from parasites and sand flies have been implicated in this attachment. In previous work, monoclonal antibodies were produced against Leishmania. Among these an antibody was obtained against Leishmania braziliensis flagella, which blocked the attachment of Leishmania panamensis flagella to Phlebotomus papatasi guts. The protein recognized by this antibody was identified and named FLAG1, and the complete FLAG1 gene sequence was obtained. This protein was later independently identified as a small, myristoylated protein and called SMP1, so from now on it will be denominated FLAG1/SMP1. The FLAG1/SMP1 gene is expressed in all developmental stages of the parasite, but has higher expression in promastigotes. The anti-FLAG1/SMP1 antibody recognized the flagellum of all Leishmania species tested and generated the expected band by western blots. This antibody was used in attachment and infection blocking experiments. Using the New World vector Lutzomyia longipalpis and Leishmania infantum chagasi, no inhibition of attachment ex vivo or infection in vivo was seen. On the other hand, when the Old World vectors P. papatasi and Leishmania major were used, a significant decrease of both attachment and infection were seen in the presence of the antibody. We propose that FLAG1/SMP1 is involved in the attachment/infection of Leishmania in the strict vector P. papatasi and not the permissive vector L. longipalpis.

  4. Natural infection of Lutzomyia tortura with Leishmania (Viannia) naiffi in an Amazonian area of Ecuador.

    Science.gov (United States)

    Kato, Hirotomo; Gomez, Eduardo A; Yamamoto, Yu-ichi; Calvopiña, Manuel; Guevara, Angel G; Marco, Jorge D; Barroso, Paola A; Iwata, Hiroyuki; Hashiguchi, Yoshihisa

    2008-09-01

    Natural infection of sand flies with Leishmania parasites was surveyed in an Amazonian area in Ecuador where leishmaniasis is endemic. Seventy-one female sand flies were dissected and one was positive for Leishmania protozoa. The species of this sand fly was identified as Lutzomyia (Lu.) tortura on the basis of morphologic characteristics. Analysis of the cytochrome b gene sequence identified the parasite as L. (Viannia) naiffi. We report the distribution of L. (V.) naiffi in Ecuador and detection of a naturally infected sand fly in the Ecuadorian Amazon and natural infection of Lu. tortura with Leishmania parasites in the New World.

  5. Generation of luciferase-expressing Leishmania infantum chagasi and assessment of miltefosine efficacy in infected hamsters through bioimaging.

    Science.gov (United States)

    Reimão, Juliana Q; Oliveira, Jordana C; Trinconi, Cristiana T; Cotrim, Paulo C; Coelho, Adriano C; Uliana, Silvia R B

    2015-02-01

    The only oral drug available for the treatment of leishmaniasis is miltefosine, described and approved for visceral leishmaniasis in India. Miltefosine is under evaluation for the treatment of cutaneous leishmaniasis in the Americas although its efficacy for the treatment of human visceral leishmaniasis caused by Leishmania infantum chagasi has not been described. Drug efficacy for visceral leishmaniasis is ideally tested in hamsters, an experimental model that mimics human disease. Luciferase has been validated as a quantitative tool for the determination of parasite burden in experimental leishmaniasis. However, there are no reports of luciferase detection in the model of progressive visceral leishmaniasis in hamsters. Therefore, the aims of this study were to generate recombinant Leishmania infantum chagasi expressing the luciferase gene (Lc-LUC), characterize the biological properties of this transgenic line as compared with the wild-type parasites and evaluate miltefosine effectiveness in Lc-LUC infected hamsters. A transgenic line containing a luciferase encoding gene integrated into the ribosomal DNA locus was obtained and shown to produce bioluminescence which correlated with the number of parasites. Lc-LUC growth curves and susceptibility to pentavalent antimony and miltefosine in vitro were indistinguishable from the wild-type parasites. The effectiveness of pentavalent antimony was evaluated in Lc-LUC infected hamsters through bioimaging and determination of Leishman Donovan Units. Both methods showed concordant results. Miltefosine was effective in the treatment of Lc-LUC-infected hamsters, as demonstrated by the reduction in parasite burden in a dose-dependent manner and by prolongation of animal survival. Luciferase expressing parasites are a reliable alternative for parasite burden quantification in hamsters with advantages such as the possibility of estimating parasite load before drug treatment and therefore allowing distribution of animals in

  6. In-silico Leishmania Target Selectivity of Antiparasitic Terpenoids

    Directory of Open Access Journals (Sweden)

    Ifedayo Victor Ogungbe

    2013-07-01

    Full Text Available Neglected Tropical Diseases (NTDs, like leishmaniasis, are major causes of mortality in resource-limited countries. The mortality associated with these diseases is largely due to fragile healthcare systems, lack of access to medicines, and resistance by the parasites to the few available drugs. Many antiparasitic plant-derived isoprenoids have been reported, and many of them have good in vitro activity against various forms of Leishmania spp. In this work, potential Leishmania biochemical targets of antiparasitic isoprenoids were studied in silico. Antiparasitic monoterpenoids selectively docked to L. infantum nicotinamidase, L. major uridine diphosphate-glucose pyrophosphorylase and methionyl t-RNA synthetase. The two protein targets selectively targeted by germacranolide sesquiterpenoids were L. major methionyl t-RNA synthetase and dihydroorotate dehydrogenase. Diterpenoids generally favored docking to L. mexicana glycerol-3-phosphate dehydrogenase. Limonoids also showed some selectivity for L. mexicana glycerol-3-phosphate dehydrogenase and L. major dihydroorotate dehydrogenase while withanolides docked more selectively with L. major uridine diphosphate-glucose pyrophosphorylase. The selectivity of the different classes of antiparasitic compounds for the protein targets considered in this work can be explored in fragment- and/or structure-based drug design towards the development of leads for new antileishmanial drugs.

  7. Glucantime resistant Leishmania promastigotes are sensitive to pentostam

    Directory of Open Access Journals (Sweden)

    Elizabeth Spangler Andrade Moreira

    1992-12-01

    Full Text Available Growth inhibition in vitro tests were used to study the susceptibility to pentostam of different Leishmania strains involved in cutaneous and mucocutaneos leishmaniasis - one glucantime sensitive strain, three naturally glucantime resistant strains and one glucantime resistant line developed by in vitro drug exposure. Contrasting with the high degree , of glucantime resistance, all strains were sensitive to pentostam. These differences suggest that there is some relationship between chemical structure and in vitro activity for these antimonial compounds. These data justify a clinical re-evaluation to compare therapeutic efficacy of glucantime and pentostam in the treatment of leishmaniasis.Diferentes amostras de Leishmania foram analisadas quanto à susceptibilidade in vitro ao pentostam - uma cepa de L. (V braziliensis considerada sensível ao glucantime, três cepas (duas L. (V braziliensis e uma L. (L amazonensis consideradas naturalmente resistentes ao glucantime, uma linhagem resistente (L. (V guyanensis selecionada in vitro pela exposição em alta concentração de droga. A elevada sensibilidade destas amostras em contraposição à resistência observada para o glucantime sugere existir relação entre a estrutura química e a atividade destes compostos. Estes dados indicam a necessidade de ima avaliação comparativa de atividade clínica do pentostam e do glucantime no tratamento da leishmaniose.

  8. Proteomic and Genomic Analyses of Antimony Resistant Leishmania infantum Mutant

    Science.gov (United States)

    Brotherton, Marie-Christine; Bourassa, Sylvie; Leprohon, Philippe; Légaré, Danielle; Poirier, Guy G.; Droit, Arnaud; Ouellette, Marc

    2013-01-01

    Background Antimonials remain the primary antileishmanial drugs in most developing countries. However, drug resistance to these compounds is increasing and our understanding of resistance mechanisms is partial. Methods/Principal Findings In the present study, quantitative proteomics using stable isotope labelling of amino acids in cell culture (SILAC) and genome next generation sequencing were used in order to better characterize in vitro generated Leishmania infantum antimony resistant mutant (Sb2000.1). Using the proteomic method, 58 proteins were found to be differentially regulated in Sb2000.1. The ABC transporter MRPA (ABCC3), a known marker of antimony resistance, was observed for the first time in a proteomic screen. Furthermore, transfection of its gene conferred antimony resistance in wild-type cells. Next generation sequencing revealed aneuploidy for 8 chromosomes in Sb2000.1. Moreover, specific amplified regions derived from chromosomes 17 and 23 were observed in Sb2000.1 and a single nucleotide polymorphism (SNP) was detected in a protein kinase (LinJ.33.1810-E629K). Conclusion/Significance Our results suggest that differentially expressed proteins, chromosome number variations (CNVs), specific gene amplification and SNPs are important features of antimony resistance in Leishmania. PMID:24312377

  9. Cutaneous leishmaniasis caused by Leishmania infantum in Southern Israel.

    Science.gov (United States)

    Ben-Shimol, Shalom; Sagi, Orli; Horev, Amir; Avni, Yonat Shemer; Ziv, Mati; Riesenberg, Klaris

    2016-12-01

    Cutaneous leishmaniasis (CL) caused by Leishmania major is common in southern Israel, while Leishmania infantum (sub-strain of L. donovani, causing zoonotic visceral leishmaniasis) infections were rarely reported in Israel and only in other regions. We report the first case of L. infantum infection in southern Israel, presented atypically as CL in an immunosuppressed 47-year old male. The patient was treated with liposomal amphotericin-B and recovered, without extra-cutaneous complications. Diagnosis of L. infantum CL was confirmed by microscopic identification of amastigotes in Gimsa-stained smear of skin lesion, positive blood serology and a positive polymerase chain reaction (PCR) amplification of the internal transcribed spacer 1 genes (ITS1) and restriction fragment length polymorphism (ITS1 PCR-RFLP). We also review the medical literature on old-world CL caused by L. infantum. Multiple L. donovani/infantum CL cases were identified in the literature search. These can be divided schematically to two: 1) In several endemic countries, L. infantum strains are the main causative agents of CL; 2) In other regions, CL is almost exclusively caused by L. major or L. tropica, while L. donovani strains CL cases were reported sporadically or as imported disease.

  10. Peptidomimetic and organometallic derivatives of primaquine active against Leishmania infantum.

    Science.gov (United States)

    Vale-Costa, Sílvia; Vale, Nuno; Matos, Joana; Tomás, Ana; Moreira, Rui; Gomes, Paula; Gomes, Maria Salomé

    2012-11-01

    The current treatment of visceral leishmaniasis is made difficult by the low efficacy, elevated costs, low bioavailability, and high toxicity of many of the available drugs. Primaquine, an antimalarial 8-aminoquinoline, displays activity against Leishmania spp., and several of its derivatives have been developed as potential antileishmanial drugs. However, primaquine exhibits low oral bioavailability due to oxidative deamination of its aliphatic chain. We previously developed peptidomimetic and organometallic derivatives of primaquine, with higher resistance to proteolytic degradation and oxidative deamination, which presented significant activity against primaquine-sensitive pathogens such as Plasmodium or Pneumocystis. In light of these relevant findings, we decided to evaluate these compounds against both the promastigote and intramacrophagic amastigote forms of Leishmania infantum, the agent of Mediterranean visceral leishmaniasis. We found that several of these compounds had significant activity against L. infantum. One of the peptidomimetic (3c) and one of the organometallic (7a) derivatives of primaquine were active against the clinically relevant intramacrophagic amastigote form of the parasite, causing >96% reductions in the number of amastigotes per 100 macrophages at 60 and 40 μM, respectively, while being less cytotoxic for host cells than the reference drugs sitamaquine and miltefosine. Hence, compounds 3c and 7a represent new entries toward the development of new antileishmanial leads.

  11. Reproduction in Leishmania: A focus on genetic exchange.

    Science.gov (United States)

    Rougeron, V; De Meeûs, T; Bañuls, A-L

    2017-06-01

    One key process of the life cycle of pathogens is their mode of reproduction. Indeed, this fundamental biological process conditions the multiplication and the transmission of genes and thus the propagation of diseases in the environment. Reproductive strategies of protozoan parasites have been a subject of debate for many years, principally due to the difficulty in making direct observations of sexual reproduction (i.e. genetic recombination). Traditionally, these parasites were considered as characterized by a preeminent clonal structure. Nevertheless, with the development of elaborate culture experiments, population genetics and evolutionary and population genomics, several studies suggested that most of these pathogens were also characterized by constitutive genetic recombination events. In this opinion, we focused on Leishmania parasites, pathogens responsible of leishmaniases, a major public health issue. We first discuss the evolutionary advantages of a mixed mating reproductive strategy, then we review the evidence of genetic exchange, and finally we detail available tools to detect naturally occurring genetic recombination in Leishmania parasites and more generally in protozoan parasites. Copyright © 2016. Published by Elsevier B.V.

  12. Exposure to Leishmania braziliensis triggers neutrophil activation and apoptosis.

    Directory of Open Access Journals (Sweden)

    Sarah A C Falcão

    2015-03-01

    Full Text Available BACKGROUND: Neutrophils are the first line of defense against invading pathogens and are rapidly recruited to the sites of Leishmania inoculation. During Leishmania braziliensis infection, depletion of inflammatory cells significantly increases the parasite load whereas co-inoculation of neutrophils plus L. braziliensis had an opposite effect. Moreover, the co-culture of infected macrophages and neutrophils also induced parasite killing leading us to ask how neutrophils alone respond to an L. braziliensis exposure. Herein we focused on understanding the interaction between neutrophils and L. braziliensis, exploring cell activation and apoptotic fate. METHODS AND FINDINGS: Inoculation of serum-opsonized L. braziliensis promastigotes in mice induced neutrophil accumulation in vivo, peaking at 24 h. In vitro, exposure of thyoglycollate-elicited inflammatory or bone marrow neutrophils to L. braziliensis modulated the expression of surface molecules such as CD18 and CD62L, and induced the oxidative burst. Using mCherry-expressing L. braziliensis, we determined that such effects were mainly observed in infected and not in bystander cells. Neutrophil activation following contact with L. braziliensis was also confirmed by the release of TNF-α and neutrophil elastase. Lastly, neutrophils infected with L. braziliensis but not with L. major displayed markers of early apoptosis. CONCLUSIONS: We show that L. braziliensis induces neutrophil recruitment in vivo and that neutrophils exposed to the parasite in vitro respond through activation and release of inflammatory mediators. This outcome may impact on parasite elimination, particularly at the early stages of infection.

  13. [Axillary hidrosadenitis due to Leishmania: Case report and literature review].

    Science.gov (United States)

    Alberca-Páramo, Ana; García-Santos, Esther Pilar; Sánchez-García, Susana; Ruescas-García, Francisco Javier; Bertelli-Puche, José Luis; Martín-Fernández, Jesús

    2016-01-01

    Hidradenitis is a disorder where abscesses appear after the infection of the apocrine sweat glands. It is located normally in the axillae, groin, perineal region, and the scalp. A 37 year old male was referred by his GP to the General Surgery Department with axillary hidradenitis which had evolved over the years. The physical examination shows signs of hidradenitis in both axillae, with a noticeable suppurative hidradenitis in the right armpit. En bloc extirpation was performed to remove the whole affected area. The pathological examination revealed a cutaneous leishmaniasis. Subsequently, fucidin was administered topically, as well as local infiltrations of one millilitre of Glucantime™. Hidradenitis normally appears in intertriginous areas and its manifestation is accompanied by recurrent subcutaneous nodules. The incidence rate in females is three times higher than in males. The isolated Hidradenitis caused by Leishmania is a rare condition presented only in endemic areas or in immunocompromised patients, such as HIV-infected patients. Clinical manifestations can be different and the diagnosis can be confirmed through haematoxylin-eosin. The main pattern displays a disorganised granuloma without necrosis. Systemic or topical treatment can be applied. Immunotherapy treatment is the most common. Hidradenitis caused by Leishmania in HIV-negative patients is a rare condition. Therefore it is important to perform a good histological diagnosis and to administer the right treatment. Copyright © 2015 Academia Mexicana de Cirugía A.C. Published by Masson Doyma México S.A. All rights reserved.

  14. Unusual forms of cutaneous leishmaniasis due to Leishmania major.

    Science.gov (United States)

    Solomon, M; Greenberger, S; Baum, S; Pavlotsky, F; Barzilai, A; Schwartz, E

    2016-07-01

    Cutaneous leishmaniasis (CL) due to Leishmania major (L. major) is common in the Middle East; however, this skin infection may be under-diagnosed when it presents atypically. To highlight the occurrence of uncommon presentations of CL that may elude diagnosis. A retrospective study was performed among patients who presented at The Sheba Medical Center between 2005 and 2014 with atypical clinical presentations of CL due to L. major. Twelve patients with unusual clinical presentations of L. major CL were identified. All infections were acquired in L. major - endemic areas of Israel. The average age was 37 years. The average number of lesions was 2. Nine patients presented with a form that mimicked other forms of CL, such as lupoid, giant ulcer, sporotrichoid and recidivans, and three had a variant resembling other infectious skin diseases, such as erysipeloid and verruciform. All patients required systemic therapy. Cutaneous leishmaniasis due to L. major can masquerade as many other infectious and inflammatory diseases. In addition, it can mimic clinical forms of New World CL. We suggest that in endemic countries or in travellers returning from countries where L. major is endemic, polymerase chain reaction (PCR) for Leishmania-specific DNA should be performed routinely in cases of unusual presentations of dermatitis with a single or a few lesions, even if a diagnosis of CL was not considered by the referring clinician. © 2015 European Academy of Dermatology and Venereology.

  15. Gene Cloning of Iranian Leishmania major Mannose-1-Phosphate Guanyltransferase

    Directory of Open Access Journals (Sweden)

    R Salehi

    2009-07-01

    Full Text Available "nBackground: Leishmania is an obligatory intracellular protozoan parasite, which infects human be­ings when infected sand fly vector takes a blood meal.  Most efforts are towards designing an effective vaccine to prevent leishmaniasis. In this way, development of candidate antigen for vaccine has spe­cial im­portant. In this study, we cloned mannose-1-phosphate guanyltransferase gene of Iranian L .major in pET32a expression vector. "nMethods: Primers based on L. major mannose-1-phosphate guanyltransferase sequence gene was de­signed and synthesized. DNA of Leishmania promastigotes was extracted and PCR reaction was done. PCR product was cloned into pTZ57R and sub cloned into pET32a expression vector. "nResults: Recombinant plasmid containing 1140 bp as L. major mannose-1-phosphate guanyltrans­ferase gene was extracted and confirmed by restriction analysis. PCR product was sequenced and de­posited to GenBank. There were some differences in amino acid sequences between Iranian L. major mannose-1-phosphate guanyltransferase and others previously accepted in GenBank "nConclusion: We amplified and cloned Iranian L. major mannose-1-phosphate guanyltransferase successfully.

  16. Crystal structure of dihydroorotate dehydrogenase from Leishmania major.

    Science.gov (United States)

    Cordeiro, Artur T; Feliciano, Patricia R; Pinheiro, Matheus P; Nonato, M Cristina

    2012-08-01

    Dihydroorotate dehydrogenase (DHODH) is the fourth enzyme in the de novo pyrimidine biosynthetic pathway and has been exploited as the target for therapy against proliferative and parasitic diseases. In this study, we report the crystal structures of DHODH from Leishmania major, the species of Leishmania associated with zoonotic cutaneous leishmaniasis, in its apo form and in complex with orotate and fumarate molecules. Both orotate and fumarate were found to bind to the same active site and exploit similar interactions, consistent with a ping-pong mechanism described for class 1A DHODHs. Analysis of LmDHODH structures reveals that rearrangements in the conformation of the catalytic loop have direct influence on the dimeric interface. This is the first structural evidence of a relationship between the dimeric form and the catalytic mechanism. According to our analysis, the high sequence and structural similarity observed among trypanosomatid DHODH suggest that a single strategy of structure-based inhibitor design can be used to validate DHODH as a druggable target against multiple neglected tropical diseases such as Leishmaniasis, Sleeping sickness and Chagas' diseases. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  17. Aurapten, a coumarin with growth inhibition against Leishmania major promastigotes

    Directory of Open Access Journals (Sweden)

    Napolitano H.B.

    2004-01-01

    Full Text Available Several natural compounds have been identified for the treatment of leishmaniasis. Among them are some alkaloids, chalcones, lactones, tetralones, and saponins. The new compound reported here, 7-geranyloxycoumarin, called aurapten, belongs to the chemical class of the coumarins and has a molecular weight of 298.37. The compund was extracted from the Rutaceae species Esenbeckia febrifuga and was purified from a hexane extract starting from 407.7 g of dried leaves and followed by four silica gel chromatographic fractionation steps using different solvents as the mobile phase. The resulting compound (47 mg of shows significant growth inhibition with an LD50 of 30 µM against the tropical parasite Leishmania major, which causes severe clinical manifestations in humans and is endemic in the tropical and subtropical regions. In the present study, we investigated the atomic structure of aurapten in order to determine the existence of common structural motifs that might be related to other coumarins and potentially to other identified inhibitors of Leishmania growth and viability. This compound has a comparable inhibitory activity of other isolated molecules. The aurapten is a planar molecule constituted of an aromatic system with electron delocalization. A hydrophobic side chain consisting of ten carbon atoms with two double bonds and negative density has been identified and may be relevant for further compound synthesis.

  18. Natural Sesquiterpene Lactones Induce Oxidative Stress in Leishmania mexicana

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    Patricia Barrera

    2013-01-01

    Full Text Available Leishmaniasis is a worldwide parasitic disease, caused by monoflagellate parasites of the genus Leishmania. In the search for more effective agents against these parasites, the identification of molecular targets has been attempted to ensure the efficiency of drugs and to avoid collateral damages on the host’s cells. In this work, we have investigated some of the mechanisms of action of a group of natural sesquiterpene lactones that are effective against Leishmania mexicana mexicana promastigotes. We first observed that the antiproliferative effect of mexicanin I (Mxc, dehydroleucodine (DhL, psilostachyin (Psi, and, at lesser extent, psilostachyin C (Psi C is blocked by 1.5 mM reduced glutathione. The reducing agent was also able to reverse the early effect of the compounds, suggesting that lactones may react with intracellular sulfhydryl groups. Moreover, we have shown that all the sesquiterpene lactones, except Psi C, significantly decreased the endogenous concentration of glutathione within the parasite. Consistent with these findings, the active sesquiterpene lactones increased between 2.7 and 5.4 times the generation of ROS by parasites. These results indicate that the induction of oxidative stress is at least one of the mechanisms of action of DhL, Mxc, and Psi on parasites while Psi C would act by another mechanism.

  19. Glibenclamide modulates glucantime activity and disposition in Leishmania major.

    Science.gov (United States)

    Padrón-Nieves, Maritza; Díaz, Emilia; Machuca, Claudia; Romero, Amarilis; Ponte Sucre, Alicia

    2009-04-01

    A source of chemotherapeutic failure in anti-infective therapies is the active movement of drugs across membranes, through ATP-binding cassette (ABC) transporters. In fact, simultaneous administration of therapeutic drugs with ABC transporter blockers has been invoked to be the way to actively prevent the emergence of drug resistance. Herein, we demonstrate that glucantime's efficacy in decreasing the infection rate of Leishmania-infected macrophages is strongly enhanced when used in combination with glibenclamide, a specific blocker of ABC transporters. Intracellular ABC transporters mediate glucantime sequestration in intracellular organelles. Their selective inhibition may effectively increase the cytoplasmic concentration of glucantime and its leishmanicidal activity. Our results reveal for the first time that glibenclamide targets in Leishmania major a compartment associated with a multivesicular system that is simultaneously labeled by the acidic marker LysoTracker-red and may represent the organelle where antimonials are sequestered. These results constitute a proof of concept that conclusively demonstrates the potential value that combination therapy with an ABC transporter blocker may have for leishmaniasis therapy.

  20. Subcellular localization of an intracellular serine protease of 68 kDa in Leishmania (Leishmania amazonensis promastigotes

    Directory of Open Access Journals (Sweden)

    José Andrés Morgado-Díaz

    2005-07-01

    Full Text Available Here we report the subcellular localization of an intracellular serine protease of 68 kDa in axenic promastigotes of Leishmania (Leishmania amazonensis, using subcellular fractionation, enzymatic assays, immunoblotting, and immunocytochemistry. All fractions were evaluated by transmission electron microscopy and the serine protease activity was measured during the cell fractionation procedure using a-N-r-tosyl-L-arginine methyl ester (L-TAME as substrate, phenylmethylsulphone fluoride (PMSF and L-1-tosylamino-2-phenylethylchloromethylketone (TPCK as specific inhibitors. The enzymatic activity was detected mainly in a membranous vesicular fraction (6.5-fold enrichment relative to the whole homogenate, but also in a crude plasma membrane fraction (2.0-fold. Analysis by SDS-PAGE gelatin under reducing conditions demonstrated that the major proteolytic activity was found in a 68 kDa protein in all fractions studied. A protein with identical molecular weight was also recognized in immunoblots by a polyclonal antibody against serine protease (anti-SP, with higher immunoreactivity in the vesicular fraction. Electron microscopic immunolocalization using the same polyclonal antibody showed the enzyme present at the cell surface, as well as in cytoplasmic membranous compartments of the parasite. Our findings indicate that the internal location of this serine protease in L. amazonensis is mainly restricted to the membranes of intracellular compartments resembling endocytic/exocytic elements.

  1. Influence of Clinical Status and Parasite Load on Erythropoiesis and Leucopoiesis in Dogs Naturally Infected with Leishmania (Leishmania) chagasi

    Science.gov (United States)

    Trópia de Abreu, Raquel; Carvalho, Maria das Graças; Carneiro, Cláudia Martins; Giunchetti, Rodolfo Cordeiro; Teixeira-Carvalho, Andréa; Martins-Filho, Olindo Assis; Coura-Vital, Wendel; Corrêa-Oliveira, Rodrigo; Reis, Alexandre Barbosa

    2011-01-01

    Background The bone marrow is considered to be an important storage of parasites in Leishmania-infected dogs, although little is known about cellular genesis in this organ during canine visceral leishmaniasis (CVL). Methodology/Principal Findings The aim of the present study was to evaluate changes in erythropoiesis and leucopoiesis in bone marrow aspirates from dogs naturally infected with Leishmania chagasi and presenting different clinical statuses and bone marrow parasite densities. The evolution of CVL from asymptomatic to symptomatic status was accompanied by increasing parasite density in the bone marrow. The impact of bone marrow parasite density on cellularity was similar in dogs at different clinical stages, with animals in the high parasite density group. Erythroid and eosinophilic hypoplasia, proliferation of neutrophilic precursor cells and significant increases in lymphocytes and plasma cell numbers were the major alterations observed. Differential bone marrow cell counts revealed increases in the myeloid:erythroid ratio associated to increased numbers of granulopoietic cells in the different clinical groups compared with non-infected dogs. Conclusions Analysis of the data obtained indicated that the assessment of bone marrow constitutes an additional and useful tool by which to elaborate a prognosis for CVL. PMID:21572995

  2. Influence of clinical status and parasite load on erythropoiesis and leucopoiesis in dogs naturally infected with leishmania (Leishmania chagasi.

    Directory of Open Access Journals (Sweden)

    Raquel Trópia de Abreu

    Full Text Available BACKGROUND: The bone marrow is considered to be an important storage of parasites in Leishmania-infected dogs, although little is known about cellular genesis in this organ during canine visceral leishmaniasis (CVL. METHODOLOGY/PRINCIPAL FINDINGS: The aim of the present study was to evaluate changes in erythropoiesis and leucopoiesis in bone marrow aspirates from dogs naturally infected with Leishmania chagasi and presenting different clinical statuses and bone marrow parasite densities. The evolution of CVL from asymptomatic to symptomatic status was accompanied by increasing parasite density in the bone marrow. The impact of bone marrow parasite density on cellularity was similar in dogs at different clinical stages, with animals in the high parasite density group. Erythroid and eosinophilic hypoplasia, proliferation of neutrophilic precursor cells and significant increases in lymphocytes and plasma cell numbers were the major alterations observed. Differential bone marrow cell counts revealed increases in the myeloid:erythroid ratio associated to increased numbers of granulopoietic cells in the different clinical groups compared with non-infected dogs. CONCLUSIONS: Analysis of the data obtained indicated that the assessment of bone marrow constitutes an additional and useful tool by which to elaborate a prognosis for CVL.

  3. Biochemical and molecular characterization of Leishmania parasites isolated from an endemic focus in eastern Sudan

    NARCIS (Netherlands)

    Oskam, L.; Pratlong, F.; Zijlstra, E. E.; Kroon, C. C.; Dedet, I. P.; Kager, P. A.; Schönian, G.; Ghalib, H. W.; El-Hassan, A. M.; Meredith, S. E.

    1998-01-01

    Twelve Leishmania isolates from visceral leishmaniasis patients in eastern Sudan were characterized using isoenzyme analysis, Southern blotting and polymerase chain reaction (PCR) 'fingerprinting'. Isoenzyme analysis revealed the presence of 3 zymodemes: MON-18, MON-30 and MON-82, corresponding to

  4. Pathologic mechanisms underlying the clinical findings in canine leishmaniasis due to Leishmania infantum/chagasi

    National Research Council Canada - National Science Library

    Koutinas, A F; Koutinas, C K

    2014-01-01

    In dogs with symptomatic or asymptomatic leishmaniasis, Leishmania infantum appears to induce a mixed Th1/Th2 immune response that in the sick dog may eventually result in tissue damage via different...

  5. Mixed infection of human U-937 cells by two different species of Leishmania.

    Science.gov (United States)

    Abdullah, S M; Flath, B; Presber, W

    1998-08-01

    Mixed infections by different Leishmania species could explain differences in the clinical course of these infections. Moreover, mixed infections of the same macrophage could be the basis for parasite recombination. We stained three strains of Leishmania (L. mexicana amazonensis, L. donovani DD8, and L. infantum D2, respectively) with different fluorescent dyes and analyzed them using a fluorescence-activated cell scanner. The simultaneous infection of one cell by Leishmania belonging to two different species was demonstrated. In additional experiments, cells with mixed infections were separated by a fluorescence-activated cell sorter and monitored for 24 hr. Preinfecting human monocytic U-937 cells with one Leishmania species did not exclude a second species added after 3 hr.

  6. DSFL database: A hub of target proteins of Leishmania sp. to combat leishmaniasis

    Directory of Open Access Journals (Sweden)

    Ameer Khusro

    2017-07-01

    Full Text Available Leishmaniasis is a vector-borne chronic infectious tropical dermal disease caused by the protozoa parasite of the genus Leishmania that causes high mortality globally. Among three different clinical forms of leishmaniasis, visceral leishmaniasis (VL or kala-azar is a systemic public health disease with high morbidity and mortality in developing countries, caused by Leishmania donovani, Leishmania infantum or Leishmania chagasi. Unfortunately, there is no vaccine available till date for the treatment of leishmaniasis. On the other hand, the therapeutics approved to treat this fatal disease is expensive, toxic, and associated with serious side effects. Furthermore, the emergence of drug-resistant Leishmania parasites in most endemic countries due to the incessant utilization of existing drugs is a major concern at present. Drug Search for Leishmaniasis (DSFL is a unique database that involves 50 crystallized target proteins of varied Leishmania sp. in order to develop new drugs in future by interacting several antiparasitic compounds or molecules with specific protein through computational tools. The structure of target protein from different Leishmania sp. is available in this database. In this review, we spotlighted not only the current global status of leishmaniasis in brief but also detailed information about target proteins of various Leishmania sp. available in DSFL. DSFL has created a new expectation for mankind in order to combat leishmaniasis by targeting parasitic proteins and commence a new era to get rid of drug resistance parasites. The database will substantiate to be a worthwhile project for further development of new, non-toxic, and cost-effective antileishmanial drugs as targeted therapies using in vitro/in vivo assays.

  7. Leishmania amazonensis exhibits phosphatidylserine-dependent procoagulant activity, a process that is counteracted by sandfly saliva

    OpenAIRE

    Rochael, Natalia Cadaxo; Lima, Luize Gonçalves; de Oliveira, Sandra Maria Pereira; Barcinski, Marcello André; Saraiva, Elvira Maria; Monteiro, Robson Queiroz; Pinto-da-Silva, Lucia Helena

    2013-01-01

    Leishmania parasites expose phosphatidylserine (PS) on their surface, a process that has been associated with regulation of host's immune responses. In this study we demonstrate that PS exposure by metacyclic promastigotes of Leishmania amazonensis favours blood coagulation. L. amazonensis accelerates in vitro coagulation of human plasma. In addition, L. amazonensis supports the assembly of the prothrombinase complex, thus promoting thrombin formation. This process was reversed by annexin V w...

  8. Expanding the knowledge about Leishmania species in wild mammals and dogs in the Brazilian savannah.

    Science.gov (United States)

    Cardoso, Rebecca Martins; de Araújo, Nadjar Nitz Silva Lociks; Romero, Gustavo Adolfo Sierra; Souza, Thaís Tâmara Castro Minuzzi; Dietrich, Ana Gabriela; Mendes, Júnio Donizette; Reis, Marcelo Lima; Ferreira, Jônatas Barbosa Cavalcante; Hecht, Mariana Machado; Gurgel-Gonçalves, Rodrigo

    2015-03-21

    Wild, synanthropic and domestic mammals act as hosts and/or reservoirs of several Leishmania spp. Studies on possible reservoirs of Leishmania in different areas are fundamental to understand host-parasite interactions and develop strategies for the surveillance and control of leishmaniasis. In the present study, we evaluated the Leishmania spp. occurrence in mammals in two conservation units and their surroundings in Brasília, Federal District (FD), Brazil. Small mammals were captured in Brasília National Park (BNP) and Contagem Biological Reserve (CBR) and dogs were sampled in residential areas in their vicinity. Skin and blood samples were evaluated by PCR using different molecular markers (D7 24Sα rRNA and rDNA ITS1). Leishmania species were identified by sequencing of PCR products. Dog blood samples were subjected to the rapid immunochromatographic test (DPP) for detection of anti-Leishmania infantum antibodies. 179 wild mammals were studied and 20.1% had Leishmania DNA successfully detected in at least one sample. Six mammal species were considered infected: Clyomys laticeps, Necromys lasiurus, Nectomys rattus, Rhipidomys macrurus, Didelphis albiventris and Gracilinanus agilis. No significant difference, comparing the proportion of individuals with Leishmania spp., was observed between the sampled areas and wild mammal species. Most of the positive samples were collected from the rodent N. lasiurus, infected by L. amazonensis or L. braziliensis. Moreover, infections by Trypanosoma spp. were detected in N. lasiurus and G. agilis. All 19 dog samples were positive by DPP; however, only three (15.8%) were confirmed by PCR assays. DNA sequences of ITS1 dog amplicons showed 100% identity with L. infantum sequence. The results suggest the participation of six species of wild mammals in the enzootic transmission of Leishmania spp. in FD. This is the first report of L. amazonensis in N. lasiurus.

  9. Impact of Leishmania mexicana infection on dendritic cell signaling and functions.

    OpenAIRE

    Irazú Contreras; Estrada, José A.; Hannah Guak; Caroline Martel; Alborz Borjian; Benjamin Ralph; Shio, Marina T.; Sylvie Fournier; Krawczyk, Connie M.; Martin Olivier

    2014-01-01

    Leishmania parasites have the ability to modify macrophage signaling pathways in order to survive and multiply within its mammalian host. They are also known to invade other cells including neutrophils, fibroblasts and dendritic cells (DCs). DCs have an important role in immunity as the link between innate and adaptive immunity, necessary for the development of an effective response; however, the impact of Leishmania mexicana infection on DCs has been poorly studied. Herein, we report that Le...

  10. Effect of Aqueous Allium cepa and Ixora brachiata Root Extract on Leishmania major Promastigotes

    OpenAIRE

    Sadeghi-Nejad, Batool; Saki, Jasem

    2014-01-01

    Background: Leishmaniasis is a major worldwide public health problem with about two to three million humans threatened by this disease annually. Allium cepa (onion) is an important dietary vegetable and was used as a herbal medicine for centuries. The root of Ixora brachiata is medicinally important. Objectives: The aim of this study was to investigate the anti-Leishmania effect of the ethanolic and methanolic extracts of Ixora brachiata root and aqueous onion extracts on Leishmania major pro...

  11. In vitro and in vivo anti-Leishmania activity of polysubstituted synthetic chalcones

    OpenAIRE

    Aponte, J. C.; Castillo, D; Estevez, Y. (Yannick); Gonzalez, G.; Arevalo, J.; Hammond, G. B.; Sauvain, Michel (ed.)

    2010-01-01

    The in vitro screening of 43 polysubstituted chalcones against Leishmania amazonensis axenic amastigotes, led to the evaluation of 9 of them in a macrophage-infected model with the two other most infectious Leishmania species prevalent in Peru (L. braziliensis and L. peruviana). The five most active and selective chalcones were studied in vivo, resulting on the identification of two chalcones with high reduction parasite burden percentages.

  12. Secretory signal peptide modification for optimized antibody-fragment expression-secretion in Leishmania tarentolae

    Directory of Open Access Journals (Sweden)

    Klatt Stephan

    2012-07-01

    Full Text Available Abstract Background Secretory signal peptides (SPs are well-known sequence motifs targeting proteins for translocation across the endoplasmic reticulum membrane. After passing through the secretory pathway, most proteins are secreted to the environment. Here, we describe the modification of an expression vector containing the SP from secreted acid phosphatase 1 (SAP1 of Leishmania mexicana for optimized protein expression-secretion in the eukaryotic parasite Leishmania tarentolae with regard to recombinant antibody fragments. For experimental design the online tool SignalP was used, which predicts the presence and location of SPs and their cleavage sites in polypeptides. To evaluate the signal peptide cleavage site as well as changes of expression, SPs were N-terminally linked to single-chain Fragment variables (scFv’s. The ability of L. tarentolae to express complex eukaryotic proteins with highly diverse post-translational modifications and its easy bacteria-like handling, makes the parasite a promising expression system for secretory proteins. Results We generated four vectors with different SP-sequence modifications based on in-silico analyses with SignalP in respect to cleavage probability and location, named pLTEX-2 to pLTEX-5. To evaluate their functionality, we cloned four individual scFv-fragments into the vectors and transfected all 16 constructs into L. tarentolae. Independently from the expressed scFv, pLTEX-5 derived constructs showed the highest expression rate, followed by pLTEX-4 and pLTEX-2, whereas only low amounts of protein could be obtained from pLTEX-3 clones, indicating dysfunction of the SP. Next, we analysed the SP cleavage sites by Edman degradation. For pLTEX-2, -4, and -5 derived scFv’s, the results corresponded to in-silico predictions, whereas pLTEX-3 derived scFv’s contained one additional amino-acid (AA. Conclusions The obtained results demonstrate the importance of SP-sequence optimization for efficient

  13. Phytochemical screening of the exudate of Aloe otallensis and its effect on Leishmania donovani

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    Zerihun Tesfaye Nigusse

    2016-06-01

    Full Text Available Objective: To evaluate the antileishmanial activity of methanolic extract of Aloe otallensis (A. otallensis on the promastigote stage of Leishmania donovani (L. donovani as compared to standard drugs and to screen its phytochemical constituents. Methods: Phytochemical screening was done by using the method mentioned by Evans and Trease on methanolic extract of the exudates of Aloe otallensis leaves. The extract was also evaluated for in vitro antileishmanial activity against L. donavani which is found from the Parasitology Unit of Black Lion Hospital. The result was compared to standard drugs of sodium stibogluconate, milfostin and paramomycin. Results: The extract has a good antileishmanial activity with an IC50 of 0.1230 μg/mL on L. donovani (AM 563. The experimental data showed that relatively it had better activity than paramomycin and milfostin but less activity than sodium stibogluconate. The data analyses were done by GraphPad Prism version 5 software after it was read by ELISA reader at the wave length of 650 nm. The phytochemical screening of the exudates of A. otallensis showed the presence of phenol, alkaloid and saponin. Conclusions: The methanol extract of the exudates of A. otallensis has a good antileishmaniasis activity and this may be attributed to phenol, alkaloid and saponin present in the plant. But it needs further analysis for the conformation of which constituent presents in high concentration to know which one has the strongest effect.

  14. The impact of distinct culture media in Leishmania infantum biology and infectivity.

    Science.gov (United States)

    Santarém, Nuno; Cunha, Joana; Silvestre, Ricardo; Silva, Cátia; Moreira, Diana; Ouellette, Marc; Cordeiro-DA-Silva, Anabela

    2014-02-01

    An ideal culture medium for Leishmania promastigotes should retain the basic characteristics of promastigotes found in sandflies (morphology and infectivity). Furthermore, the media should not create a bias in experimental settings, thus enabling the proper extrapolation of results. To assess this we studied several established media for promastigote growth. We analysed morphology, viability, cell cycle progression, metacyclic profile, capacity to differentiate into axenic amastigotes and infectivity. Furthermore, using a rational approach from the evaluated media we developed a simple serum-free medium (cRPMI). We report that parasites growing in different media present different biological characteristics and distinct in vitro and in vivo infectivities. The developed medium, cRPMI, proved to be a less expensive substitute for traditional serum-supplemented media for the in vitro maintenance of promastigotes. In fact, cRPMI is ideal for the maintenance of parasites in the laboratory, diminishing the expected loss of virulence over time typical of the parasite cultivation. Ultimately this report is a clear warning that the normalization of culture media should be a real concern in the field as media-specific phenomena are sufficient to induce biological bias with consequences in infectivity and general parasite biology.

  15. Dynamics of sterol synthesis during development of Leishmania spp. parasites to their virulent form.

    Science.gov (United States)

    Yao, Chaoqun; Wilson, Mary E

    2016-04-12

    The Leishmania spp. protozoa, the causative agents of the "neglected" tropical disease leishmaniasis, are transmitted to mammals by sand fly vectors. Within the sand fly, parasites transform from amastigotes to procyclic promastigotes, followed by development of virulent (metacyclic) promastigote forms. The latter are infectious to mammalian hosts. Biochemical components localized in the parasite plasma membrane such as proteins and sterols play a pivotal role in Leishmania pathogenesis. Leishmania spp. lack the enzymes for cholesterol synthesis, and the dynamics of sterol acquisition and biosynthesis in parasite developmental stages are not understood. We hypothesized that dynamic changes in sterol composition during metacyclogenesis contribute to the virulence of metacyclic promastigotes. Sterols were extracted from logarithmic phase or metacyclic promastigotes grown in liquid culture with or without cholesterol, and analyzed qualitatively and quantitatively by gas chromatograph-mass spectrometry (GC-MS). TriTrypDB was searched for identification of genes involved in Leishmania sterol biosynthetic pathways. In total nine sterols were identified. There were dynamic changes in sterols during promastigote metacyclogenesis. Cholesterol in the culture medium affected sterol composition in different parasite stages. There were qualitative and relative quantitative differences between the sterol content of virulent versus avirulent parasite strains. A tentative sterol biosynthetic pathway in Leishmania spp. promastigotes was identified. Significant differences in sterol composition were observed between promastigote stages, and between parasites exposed to different extracellular cholesterol in the environment. These data lay the foundation for further investigating the role of sterols in the pathogenesis of Leishmania spp. infections.

  16. Leishmania exosomes and other virulence factors: Impact on innate immune response and macrophage functions.

    Science.gov (United States)

    Atayde, Vanessa Diniz; Hassani, Kasra; da Silva Lira Filho, Alonso; Borges, Andrezza Raposo; Adhikari, Anupam; Martel, Caroline; Olivier, Martin

    2016-11-01

    Leishmania parasites are the causative agents of the leishmaniases, a collection of vector-borne diseases that range from simple cutaneous to fatal visceral forms. Employing potent immune modulation mechanisms, Leishmania is able to render the host macrophage inactive and persist inside its phagolysosome. In the last few years, the role of exosomes in Leishmania-host interactions has been increasingly investigated. For instance, it was reported that Leishmania exosome release is augmented following temperature shift, a condition mimicking parasite's entry into its mammalian host. Leishmania exosomes were found to strongly affect macrophage cell signaling and functions, similarly to whole parasites. Importantly, these vesicles were shown to be pro-inflammatory, capable to recruit neutrophils at their inoculation site exacerbating the pathology. In this review, we provide the most recent insights on the role of exosomes and other virulence factors, especially the surface protease GP63, in Leishmania-host interactions, deepening our knowledge on leishmaniasis and paving the way for the development of new therapeutics. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Molecular and Antigenic Characterization of the Leishmania (Viannia panamensis Kinetoplastid Membrane Protein-11

    Directory of Open Access Journals (Sweden)

    Ramírez José R

    1998-01-01

    Full Text Available The kinetoplastid membrane protein 11 (KMP-11 has been recently described in Leishmania (Leishmania donovani as a major component of the promastigote membrane. Two oligonucleotide primers were synthesized to PCR-amplify the entire coding region of New World Leishmania species. The Leishmania (Viannia panamensis amplification product was cloned, sequenced and the putative amino acid sequence determined. A remarkably high degree of sequence homology was observed with the corresponding molecule of L. (L donovani and L. (L infantum (97% and 96%, respectively. Southern blot analysis showed that the KMP-11 locus is conformed by three copies of the gene. The L. (V panamensis ORF was subsequently cloned in a high expression vector and the recombinant protein was induced and purified from Escherichia coli cultures. Immunoblot analysis showed that 80%, 77% and 100% sera from cutaneous, mucocutaneous and visceral leishmaniasis patients, respectively, recognized the recombinant KMP-11 protein. In a similar assay, 86% of asymptomatic Leishmania-infected individuals showed IgG antibodies against the rKMP-11. We propose that KMP-11 could be used as a serologic marker for infection and disease caused by Leishmania in America.

  18. Could Phlebotomus mascittii play a role as a natural vector for Leishmania infantum? New data.

    Science.gov (United States)

    Obwaller, Adelheid G; Karakus, Mehmet; Poeppl, Wolfgang; Töz, Seray; Özbel, Yusuf; Aspöck, Horst; Walochnik, Julia

    2016-08-19

    The occurrence of phlebotomine sand flies in Central Europe was questioned until they were recorded for the first time in Germany in 1999, and ten years later also in Austria. The aim of this study was to investigate sand flies collected in Austria for their carrier status of Leishmania spp. From 2012 to 2013 field studies were conducted in eastern Austria. Altogether, 22 individuals of sand flies were found, all morphologically identified as Phlebotomus (Transphlebotomus) mascittii Grassi, 1908. Twelve non-engorged female specimens with no visible remnants of a blood meal in their bodies were individually investigated for Leishmania spp. by ITS-1 real-time PCR. One out of these was positive for Leishmania, identified as Leishmania infantum by DNA sequencing. This finding suggests that L. infantum is not excreted by P. mascittii and possibly can establish an infection within P. mascittii. Interestingly, an asymptomatic dog living on the farm where this sand fly had been caught was also Leishmania-positive. This study provides new data on the suspected vector capacity of P. mascittii, being the northernmost sand fly species in Europe and in most central European regions the only sand fly species found. Proven vector capacity of P. mascittii for Leishmania spp. would be of significant medico-veterinary importance, not only with respect to expanding sand fly populations in Central Europe related to global warming, but also in the light of globalization and increasing movements of humans.

  19. In vitro anti-Leishmania activity of tetracyclic iridoids from Morinda lucida, benth.

    Science.gov (United States)

    Amoa-Bosompem, Michael; Ohashi, Mitsuko; Mosore, Mba-Tihssommah; Agyapong, Jeffrey; Tung, Nguyen Huu; Kwofie, Kofi D; Ayertey, Frederick; Owusu, Kofi Baffuor-Awuah; Tuffour, Isaac; Atchoglo, Philip; Djameh, Georgina I; Azerigyik, Faustus A; Botchie, Senyo K; Anyan, William K; Appiah-Opong, Regina; Uto, Takuhiro; Morinaga, Osamu; Appiah, Alfred A; Ayi, Irene; Shoyama, Yukihiro; Boakye, Daniel A; Ohta, Nobuo

    2016-01-01

    Leishmaniasis is an infectious disease transmitted by the sand fly. It is caused by over 20 different species of Leishmania and has affected over 14 million people worldwide. One of the main forms of control of leishmaniasis is chemotherapy, but this is limited by the high cost and/or toxicity of available drugs. We previously found three novel compounds with an iridoid tetracyclic skeleton to have activity against trypanosome parasites. In this study, we determined the activity of the three anti-trypanosome compounds against Leishmania using field strain, 010, and the lab strain Leishmania hertigi. The minimum inhibitory concentration (MIC) of the compounds against 010 was determined by microscopy while the IC50 of compounds against L. hertigi was determined by fluorescence-activated cell sorting with Guava viacount analysis. We found two of the three compounds, molucidin and ML-F52, to have anti-Leishmania activity against both strains. The fluor-microscope observation with DAPI stain revealed that both Molucidin and ML-F52 induced abnormal parasites with two sets of nucleus and kinetoplast in a cell, suggesting that compounds might inhibit cytokinesis in Leishmania parasites. Molucidin and ML-F52 might be good lead compounds for the development of new anti-Leishmania chemotherapy.

  20. Detection of Leishmania spp in silvatic mammals and isolation of Leishmania (Viannia braziliensis from Rattus rattus in an endemic area for leishmaniasis in Minas Gerais State, Brazil.

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    Agnes Antônia Sampaio Pereira

    Full Text Available Knowledge of potential reservoirs of Leishmania spp. in an anthropic environment is important so that surveillance and control measures can be implemented. The aim of this study was to investigate the infection by Leishmania in small mammals in an area located in Minas Gerais, Brazil, that undergoes changes in its natural environment and presents autochthonous human cases of cutaneous leishmaniasis (CL and visceral leishmaniasis (VL. For the capture of the animals, Sherman and Tomahawk traps were used and distributed in the peridomicile of houses with reports of autochthonous cases of CL or VL. Six catches were carried out on two consecutive nights with intervals of two months during one year and samples of spleen, liver, tail skin, ear skin and bone marrow of the animals were obtained. Parasitological and molecular methods were used to detect the infection. Identification of the Leishmania species was performed by PCR RFLPhsp70. Twenty five animals of four species were captured: ten Rattus rattus, nine Didelphis albiventris, five Cerradomys subflavus and one Marmosops incanus. In the PCR-hsp70, five animals were positive (20%. The Leishmania species identified in PCR-RFLPhsp70 were: Leishmania braziliensis in D. albiventris (2, C. subflavus (1 and R. rattus (1 and Leishmania infantum in R. rattus (1. The highest positivity rate for L. braziliensis was obtained in the liver samples. The spleen was the only tissue positive for L. infantum. It was isolated in culture medium L. braziliensis from two samples (liver and spleen of R. rattus. This is the first record of isolation of L. braziliensis from R. rattus in the southeastern region of Brazil. These results are relevant to the knowledge of the epidemiology of leishmaniasis in the region, mainly in the investigation of the presence of hosts and possible reservoirs of the parasite.

  1. Large-Scale Investigation of Leishmania Interaction Networks with Host Extracellular Matrix by Surface Plasmon Resonance Imaging

    Science.gov (United States)

    Fatoux-Ardore, Marie; Peysselon, Franck; Weiss, Anthony; Bastien, Patrick; Pratlong, Francine

    2014-01-01

    We have set up an assay to study the interactions of live pathogens with their hosts by using protein and glycosaminoglycan arrays probed by surface plasmon resonance imaging. We have used this assay to characterize the interactions of Leishmania promastigotes with ∼70 mammalian host biomolecules (extracellular proteins, glycosaminoglycans, growth factors, cell surface receptors). We have identified, in total, 27 new partners (23 proteins, 4 glycosaminoglycans) of procyclic promastigotes of six Leishmania species and 18 partners (15 proteins, 3 glycosaminoglycans) of three species of stationary-phase promastigotes for all the strains tested. The diversity of the interaction repertoires of Leishmania parasites reflects their dynamic and complex interplay with their mammalian hosts, which depends mostly on the species and strains of Leishmania. Stationary-phase Leishmania parasites target extracellular matrix proteins and glycosaminoglycans, which are highly connected in the extracellular interaction network. Heparin and heparan sulfate bind to most Leishmania strains tested, and 6-O-sulfate groups play a crucial role in these interactions. Numerous Leishmania strains bind to tropoelastin, and some strains are even able to degrade it. Several strains interact with collagen VI, which is expressed by macrophages. Most Leishmania promastigotes interact with several regulators of angiogenesis, including antiangiogenic factors (endostatin, anastellin) and proangiogenic factors (ECM-1, VEGF, and TEM8 [also known as anthrax toxin receptor 1]), which are regulated by hypoxia. Since hypoxia modulates the infection of macrophages by the parasites, these interactions might influence the infection of host cells by Leishmania. PMID:24478075

  2. Advanced Development of Leishmania Topical Skin Test Antigen

    Science.gov (United States)

    2012-09-28

    Microbiological Assay Test for the Presence of Non Agar Cultivable Mycoplasma using Vero Cell Culture Assay Assays Performed on Leishmania tropica...2 2.2 CHARACTERIZATION OF CELL BANKS………………………………………………………………3 2.3 FORMULATION STUDIES……………………………………………………………..………………3 2.4 MANUFACTURE OF...Candida albicans (Candin®) for use in the detection of cell -mediated immunity. For this reason, Allermed was recognized by the U.S. Army as uniquely

  3. Interaction of Leishmania (L. chagasi with the Vero cell line

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    Pessotti J.H.

    2004-03-01

    Full Text Available The Vero cell line, a non-phagocytic cell, has supported the intracellular mechanism of Leishmania (L. chagasi. This strain (MHOM/BR/501/MS00 was isolated from a human case of visceral leishmaniasis in Mato Grosso do Sul, Brazil and cultivated in Schneider's Drosophila medium with 20 % of heat inactivated fetal calf serum. It was allowed to infect the Vero cells at a ratio of 10 to 20 promastigotes per cell. Within six hours of incubation, promastigote forms were found attached to Vero cells without any particular orientation. The number of amastigotes per cell increased during the incubation period. Results showed that promastigotes of L. (L.. chagasi could interact, transform to amastigote forms and multiply in non-phagocytic cells, demonstrating a new model to study the intracellular cycle of this protozoan.

  4. Interaction of Leishmania (L.) chagasi with the Vero cell line.

    Science.gov (United States)

    Pessotti, J H; Zaverucha Do Valle, T; Corte-Real, S; Gonçalves Da Costa, S C

    2004-03-01

    The Vero cell line, a non-phagocytic cell, has supported the intracellular mechanism of Leishmania (L.) chagasi. This strain (MHOM/BR/501/MS00) was isolated from a human case of visceral leishmaniasis in Mato Grosso do Sul, Brazil and cultivated in Schneider's Drosophila medium with 20% of heat inactivated fetal calf serum. It was allowed to infect the Vero cells at a ratio of 10 to 20 promastigotes per cell. Within six hours of incubation, promastigote forms were found attached to Vero cells without any particular orientation. The number of amastigotes per cell increased during the incubation period. Results showed that promastigotes of L. (L.) chagasi could interact, transform to amastigote forms and multiply in non-phagocytic cells, demonstrating a new model to study the intracellular cycle of this protozoan.

  5. Induction of allopurinol resistance in Leishmania infantum isolated from dogs.

    Science.gov (United States)

    Yasur-Landau, Daniel; Jaffe, Charles L; Doron-Faigenboim, Adi; David, Lior; Baneth, Gad

    2017-09-01

    Resistance to allopurinol in zoonotic canine leishmaniasis has been recently shown to be associated with disease relapse in naturally-infected dogs. However, information regarding the formation of resistance and its dynamics is lacking. This study describes the successful in-vitro induction of allopurinol resistance in Leishmania infantum cultured under increasing drug pressure. Allopurinol susceptibility and growth rate of induced parasites were monitored over 23 weeks and parasite clones were tested at selected time points and compared to their parental lines, both as promastigotes and as amastigotes. Allopurinol resistance was formed in strains from two parasite stocks producing a 20-fold rise in IC50 along three distinct growth phases. In addition, characteristic differential clustering of single nucleotide polymorphisms (SNP) was found in drug sensitive and resistant parasite clones. Results confirm that genetic polymorphism, as well as clonal heterogeneity, contribute to in-vitro resistance to allopurinol, which is likely to occur in natural infection.

  6. Induction of allopurinol resistance in Leishmania infantum isolated from dogs.

    Directory of Open Access Journals (Sweden)

    Daniel Yasur-Landau

    2017-09-01

    Full Text Available Resistance to allopurinol in zoonotic canine leishmaniasis has been recently shown to be associated with disease relapse in naturally-infected dogs. However, information regarding the formation of resistance and its dynamics is lacking. This study describes the successful in-vitro induction of allopurinol resistance in Leishmania infantum cultured under increasing drug pressure. Allopurinol susceptibility and growth rate of induced parasites were monitored over 23 weeks and parasite clones were tested at selected time points and compared to their parental lines, both as promastigotes and as amastigotes. Allopurinol resistance was formed in strains from two parasite stocks producing a 20-fold rise in IC50 along three distinct growth phases. In addition, characteristic differential clustering of single nucleotide polymorphisms (SNP was found in drug sensitive and resistant parasite clones. Results confirm that genetic polymorphism, as well as clonal heterogeneity, contribute to in-vitro resistance to allopurinol, which is likely to occur in natural infection.

  7. Leishmania: origin, evolution and future since the Precambrian.

    Science.gov (United States)

    Tuon, Felipe Francisco; Neto, Vicente Amato; Amato, Valdir Sabbaga

    2008-11-01

    This brief review discusses the history of leishmaniasis, considering its origin from the Paleoartic, Neoartic or Neotropic. We reassess some of the theories of the likely origin of this protozoan since the beginning of life on Earth, passing through the Mesozoic and continuing to the appearance of humans. The relationship between this parasite or its ancestors, possible vectors and hosts with regard to ecological modifications is discussed. Recent molecular techniques have helped to elucidate some of the evolutionary questions regarding Leishmania, but have also brought doubts about the origin and evolution of this human parasite. PCR has been used for studies in the new discipline of paleoparasitology, helping to elucidate some of the remaining evolutionary questions. Understanding of this global condition is fundamental in determining the best approach to use against the parasite, specifically for the development of an efficient vaccine.

  8. Leishmania spp. Epidemiology of Canine Leishmaniasis in the Yucatan Peninsula

    Science.gov (United States)

    López-Céspedes, A.; Longoni, S. S.; Sauri-Arceo, C. H.; Sánchez-Moreno, M.; Rodríguez-Vivas, R. I.; Escobedo-Ortegón, F. J.; Barrera-Pérez, M. A.; Bolio-González, M. E.; Marín, C.

    2012-01-01

    Canine Leishmaniasis is widespread in various Mexican states, where different species of Leishmania have been isolated from dogs. In the present study, we describe the detection of L. braziliensis, L. infantum, and L. mexicana in serum of dogs from the states of Yucatan and Quintana Roo in the Yucatan Peninsula (Mexico). A total of 412 sera were analyzed by ELISA using the total extract of the parasite and the iron superoxide dismutase excreted by different trypanosomatids as antigens. We found the prevalence of L. braziliensis to be 7.52%, L. infantum to be 6.07%, and L. mexicana to be 20.63%, in the dog population studied. The results obtained with ELISA using iron superoxide dismutase as the antigen were confirmed by western blot analysis with its greater sensitivity, and the agreement between the two techniques was very high. PMID:22927792

  9. Leishmania spp. Epidemiology of Canine Leishmaniasis in the Yucatan Peninsula

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    A. López-Céspedes

    2012-01-01

    Full Text Available Canine Leishmaniasis is widespread in various Mexican states, where different species of Leishmania have been isolated from dogs. In the present study, we describe the detection of L. braziliensis, L. infantum, and L. mexicana in serum of dogs from the states of Yucatan and Quintana Roo in the Yucatan Peninsula (Mexico. A total of 412 sera were analyzed by ELISA using the total extract of the parasite and the iron superoxide dismutase excreted by different trypanosomatids as antigens. We found the prevalence of L. braziliensis to be 7.52%, L. infantum to be 6.07%, and L. mexicana to be 20.63%, in the dog population studied. The results obtained with ELISA using iron superoxide dismutase as the antigen were confirmed by western blot analysis with its greater sensitivity, and the agreement between the two techniques was very high.

  10. Detection of Leishmania infantum in captive wolves from Southwestern Europe.

    Science.gov (United States)

    Sastre, Natalia; Francino, Olga; Ramírez, Oscar; Enseñat, Conrad; Sánchez, Armand; Altet, Laura

    2008-11-25

    The aim of the present study was to determine the prevalence of Leishmania infantum infection in a wild reservoir host (Canis lupus) throughout an endemic area for the disease (Southern Europe). For that reason, the serum and peripheral blood samples of 33 captive wolves from the European Breeding of Endangered Species Programme (EEP) were analyzed using the enzyme-linked immunosorbent assay (ELISA) and real-time quantitative PCR (qPCR). L. infantum was detected in three samples from Central Portugal and Central and Northern Spain. Even though L. infantum infection in positive samples was low, surveillance of zoonotic leishmaniosis in this population is recommended as the parasite load could be higher in other tissues due to parasite tropism and most of the EEP institutions studied are located in endemic areas for canine leishmaniosis in Europe.

  11. Parasite genome analysis. Progress in the Leishmania genome project.

    Science.gov (United States)

    Blackwell, J M

    1997-01-01

    Genome projects have been established for 7 major groups of human parasitic infections: malaria, leishmaniasis, African trypanosomiasis, American trypanosomiasis, toxoplasmosis, schistosomiasis and filariasis. All except malaria and toxoplasmosis have come under the umbrella of the World Health Organization's Strategic Committee on Parasite Genome Analysis. The focus of this meeting of the Society was to review progress made in the Leishmania and African trypanosome genome projects. This paper introduces the genome projects and reviews briefly progress in pulsed-field gel karyotype mapping and gene identification via expressed sequence tag sequencing for the leishmaniasis genome project. The overall aim of the genome projects is to harness the latest developments in molecular genetic technology and sequence analysis for the rapid-generation of new data which may, in turn, revolutionize our approaches to the study of the biology of these organisms.

  12. Effect of ionizing radiation on the morphology, physiology and growth of Leishmania ssp; Acao da radiacao ionizante sobre a morfologia, fisiologia e crescimento da Leishmania spp

    Energy Technology Data Exchange (ETDEWEB)

    Bonetti, Franco C.; Spencer, Patrick J.; Nascimento, Nanci do [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Junior A, Heitor F. [Sao Paulo Univ., SP (Brazil). Faculdade de Medicina. Instituto de Medicina Tropical

    2000-07-01

    The Leishmania spp is a pathogenic protozoan, which cause different diseases in man. The human diseases, in America, caused by this group of protozoa are divided in cutaneous or tegumentar and visceral, known as kala-azar. In this work, our principal study object was the specie that causes tegumentar leishmaniasis, in Brazil. Metabolic studies of cellular respiration and proteins and nucleic acids synthesis were accomplished using radiation as a form of sterilizing the parasites without however affecting their immunogenic capacity The promastigotes forms of irradiated Leishmania spp were totally sterilized with the dose of 1500 Gy, with their reproductive and nucleic acids, as well as protein synthesis capacity blocked. (author)

  13. Infecção natural de Equus asinus por Leishmania braziliensis braziliensis - Bahia, Brasil Natural infection of Equus asinus by Leishmania braziliensis braziliensis - Bahia, Brazil

    OpenAIRE

    Julio A. Vexenat; Air C. Barretto; Ana de Cassia O. Rosa; Christiane C. Sales; Albino V. Magalhães

    1986-01-01

    Em Corte de Pedra, Valença, Bahia, foi encontrado um jumento (Equus asinus), com infecção natural por Leishmania braziliensis braziliensis. O parasito foi isolado de uma lesão localizada na cicatriz da castração e identificado através de anticorpos monoclonais.In Corte de Pedra, Valença, state of Bahia, a donkey, Equus asinus, was found naturally infected with Leishmania braziliensis braziliensis. The parasite was isolated from a lesion located on a castration scar, and identified by means of...

  14. Infecção natural de Equus asinus por Leishmania braziliensis braziliensis - Bahia, Brasil Natural infection of Equus asinus by Leishmania braziliensis braziliensis - Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Julio A. Vexenat

    1986-06-01

    Full Text Available Em Corte de Pedra, Valença, Bahia, foi encontrado um jumento (Equus asinus, com infecção natural por Leishmania braziliensis braziliensis. O parasito foi isolado de uma lesão localizada na cicatriz da castração e identificado através de anticorpos monoclonais.In Corte de Pedra, Valença, state of Bahia, a donkey, Equus asinus, was found naturally infected with Leishmania braziliensis braziliensis. The parasite was isolated from a lesion located on a castration scar, and identified by means of monoclonal antibodies.

  15. Allopurinol Resistance in Leishmania infantum from Dogs with Disease Relapse.

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    Daniel Yasur-Landau

    2016-01-01

    Full Text Available Visceral leishmaniasis caused by the protozoan Leishmania infantum is a zoonotic, life threatening parasitic disease. Domestic dogs are the main peridomestic reservoir, and allopurinol is the most frequently used drug for the control of infection, alone or in combination with other drugs. Resistance of Leishmania strains from dogs to allopurinol has not been described before in clinical studies.Following our observation of clinical disease relapse in dogs under allopurinol treatment, we tested susceptibility to allopurinol of L. infantum isolated from groups of dogs pre-treatment, treated in remission, and with disease relapse during treatment. Promastigote isolates obtained from four treated relapsed dogs (TR group showed an average half maximal inhibitory concentration (IC50 of 996 μg/mL. A significantly lower IC50 (P = 0.01 was found for isolates from ten dogs before treatment (NT group, 200 μg/mL, as well as for five isolates obtained from treated dogs in remission (TA group, 268 μg/mL. Axenic amastigotes produced from isolates of the TR group also showed significantly higher (P = 0.002 IC50 compared to the NT group (1678 and 671 μg/mL, respectively. The lower sensitivity of intracellular amastigotes from the TR group relative to those from the NT group (P = 0.002 was confirmed using an infected macrophage model (6.3% and 20% growth inhibition, respectively at 300 μg/mL allopurinol.This is the first study to demonstrate allopurinol resistance in L. infantum and to associate it with disease relapse in the canine host. These findings are of concern as allopurinol is the main drug used for long term control of the disease in dogs, and resistant L. infantum strains may enhance uncontrolled transmission to humans and to other dogs.

  16. Allopurinol Resistance in Leishmania infantum from Dogs with Disease Relapse.

    Science.gov (United States)

    Yasur-Landau, Daniel; Jaffe, Charles L; David, Lior; Baneth, Gad

    2016-01-01

    Visceral leishmaniasis caused by the protozoan Leishmania infantum is a zoonotic, life threatening parasitic disease. Domestic dogs are the main peridomestic reservoir, and allopurinol is the most frequently used drug for the control of infection, alone or in combination with other drugs. Resistance of Leishmania strains from dogs to allopurinol has not been described before in clinical studies. Following our observation of clinical disease relapse in dogs under allopurinol treatment, we tested susceptibility to allopurinol of L. infantum isolated from groups of dogs pre-treatment, treated in remission, and with disease relapse during treatment. Promastigote isolates obtained from four treated relapsed dogs (TR group) showed an average half maximal inhibitory concentration (IC50) of 996 μg/mL. A significantly lower IC50 (P = 0.01) was found for isolates from ten dogs before treatment (NT group, 200 μg/mL), as well as for five isolates obtained from treated dogs in remission (TA group, 268 μg/mL). Axenic amastigotes produced from isolates of the TR group also showed significantly higher (P = 0.002) IC50 compared to the NT group (1678 and 671 μg/mL, respectively). The lower sensitivity of intracellular amastigotes from the TR group relative to those from the NT group (P = 0.002) was confirmed using an infected macrophage model (6.3% and 20% growth inhibition, respectively at 300 μg/mL allopurinol). This is the first study to demonstrate allopurinol resistance in L. infantum and to associate it with disease relapse in the canine host. These findings are of concern as allopurinol is the main drug used for long term control of the disease in dogs, and resistant L. infantum strains may enhance uncontrolled transmission to humans and to other dogs.

  17. Subversion and utilization of host innate defense by Leishmania amazonensis

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    Lynn eSoong

    2012-03-01

    Full Text Available Infection with Leishmania amazonensis and other members of the L. mexicana complex can lead to diverse clinical manifestations, some of which are relatively difficult to control, even with standard chemotherapy. Diffuse cutaneous leishmaniasis is a rare but severe form, and its clinical hallmark is excessive parasitic growth in infected cells accompanied by profound impairments in host immune responses to the parasites. Since these parasites also cause non-healing cutaneous leishmaniasis in most inbred strains of mice, these animals are valuable models for dissecting the mechanisms of persistent infection and disease pathogenesis. In comparison to other Leishmania species, L. amazonensis infections are most remarkable for their ability to repress the activation and effector functions of macrophages, dendritic cells and CD4+ T cells, implying discrete mechanisms at work. In addition to this multilateral suppression of host innate and adaptive immunity, the activation of types I and II interferon-mediated responses and autophagic/lipid metabolic pathways actually promotes rather than restrains L. amazonensis infection. These seemingly contradictory findings reflect the remarkable adaptation of the parasites to the ancient defense machinery of the host, as well as the complex parasite-host interactions at different stages of infection, which collectively contribute to non-healing leishmaniasis in the New World. This review article highlights new evidence that reveals the strategies utilized by L. amazonensis parasites to subvert or modulate host innate defense machinery in neutrophils and macrophages, as well as the regulatory roles of host innate responses in promoting parasite survival and replication within the huge parasitophorous vacuoles. A better understanding of unique features in host responses to these parasites at early and late stages of infection is important for the rational design of control strategies for non-healing leishmaniasis.

  18. Spread of Leishmania infantum in Europe with dog travelling.

    Science.gov (United States)

    Maia, Carla; Cardoso, Luís

    2015-09-30

    Leishmania infantum is the etiological agent of canine leishmaniosis (CanL) in Europe, where it is endemic in the Mediterranean region, with dogs being considered the major reservoir of the parasite for humans and other mammalian hosts. The main transmission mode of Leishmania is by the bite of infected phlebotomine sand fly insects (genus Phlebotomus), which are the only proven vectors of this zoonotic protozoan. Less common, non-vectorial transmission between dogs include infection through transfused blood products from infected donors, transplacental and venereal transmission. CanL has exhibited an expansion to new locations in Europe, mainly northwards, either by territorial contiguity, often in association with global warming that favours vectorial transmission, or by the long-distance importation of infected dogs. The increasing incidence of CanL in countries where the disease is not endemic is challenging owners, veterinarians and government authorities. Most infected dogs in these new areas have been relocated from or travelled with their owners to endemic regions, but in some cases transmission might have also been autochthonous. In the absence of prophylactic measures, the introduction of infected dogs in areas previously free of endemic CanL but which have competent sand fly vectors can result in a potential persistence of L. infantum. The spread of L. infantum in Europe is reviewed with a focus on transmission, epidemiology and geographic distribution of endemic and non-endemic CanL, infection and disease in humans and animal hosts other than dogs, together with prevention and additional control strategies. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Diagnostic Accuracy of the Leishmania OligoC-TesT and NASBA-Oligochromatography for Diagnosis of Leishmaniasis in Sudan: e776

    National Research Council Canada - National Science Library

    Alfarazdeg A Saad; Nuha G Ahmed; Osman S Osman; Ahmed Almustafa Al-Basheer; Awad Hamad; Stijn Deborggraeve; Philippe Büscher; Gerard J Schoone; Henk D Schallig; Thierry Laurent; Ahmed Haleem; Omran F Osman; Ahmed Mohamedain Eltom; Mustafa I Elbashir; Sayda El-Safi

    2010-01-01

      Background The Leishmania OligoC-TesT and NASBA-Oligochromatography (OC) were recently developed for simplified and standardised molecular detection of Leishmania parasites in clinical specimens...

  20. Sand fly captures with Disney traps in area of occurrence of Leishmania (Leishmania amazonensis in the state of Mato Grosso do Sul, mid-western Brazil Capturas de flebotomíneos com armadilhas de Disney em área de ocorrência de Leishmania (Leishmania amazonensis no estado de Mato Grosso do Sul, região Centro-Oeste do Brasil

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    Maria Elizabeth Cavalheiros Dorval

    2010-10-01

    Full Text Available INTRODUCTION: The work was conducted to study phlebotomine fauna (Diptera: Psychodidae and aspects of American cutaneous leishmaniasis transmission in a forested area where Leishmania (Leishmania amazonensis occurs, situated in the municipality of Bela Vista, State of Mato Grosso do Sul, Brazil. METHODS: The captures were conducted with modified Disney traps, using hamster (Mesocricetus auratus as bait, from May 2004 to January 2006. RESULTS: Ten species of phlebotomine sandflies were captured: Brumptomyia avellari, Brumptomyia brumpti, Bichromomyia flaviscutellata, Evandromyia bourrouli, Evandromyia lenti, Lutzomyia longipalpis, Psathyromyia campograndensis, Psathyromyia punctigeniculata, Psathyromyia shannoni and Sciopemyia sordellii. The two predominant species were Ev bourrouli (57.3% and Bi flaviscutellata (41.4%, present at all sampling sites. Two of the 36 hamsters used as bait presented natural infection with Leishmania. The parasite was identified as Leishmania (Leishmania amazonensis. CONCLUSIONS: Analysis of the results revealed the efficiency of Disney traps for capturing Bichromomyia flaviscutellata and the simultaneous presence of both vector and the Leishmania species transmitted by the same can be considered a predictive factor of the occurrence of leishmaniasis outbreaks for the human population that occupies the location.INTRODUÇÃO: O estudo foi realizado com o objetivo de estudar a fauna de flebotomíneos (Diptera: Psychodidae e aspectos ligados à transmissão da leishmaniose tegumentar americana em uma área florestal com ocorrência de Leishmania (Leishmania amazonensis, situada no município de Bela Vista, Estado do Mato Grosso do Sul, Brasil. MÉTODOS: As capturas de flebotomíneos foram realizadas utilizando-se armadilhas tipo Disney modificadas, com isca roedor, Mesocricetus auratus, no período de maio de 2004 a janeiro de 2006. RESULTADOS: As coletas resultaram na identificação de 10 espécies de Phlebotominae

  1. Natural infection of Algerian hedgehog, Atelerix algirus (Lereboullet 1842) with Leishmania parasites in Tunisia.

    Science.gov (United States)

    Chemkhi, Jomaa; Souguir, Hejer; Ali, Insaf Bel Hadj; Driss, Mehdi; Guizani, Ikram; Guerbouj, Souheila

    2015-10-01

    In Tunisia, Leishmania parasites are responsible of visceral leishmaniasis, caused by Leishmania infantum species while three cutaneous disease forms are documented: chronic cutaneous leishmaniasis due to Leishmania killicki, sporadic cutaneous form (SCL) caused by L. infantum and the predominant zoonotic cutaneous leishmanaisis (ZCL) due to Leishmania major. ZCL reservoirs are rodents of the Psammomys and Meriones genera, while for SCL the dog is supposed to be a reservoir. Ctenodactylus gundii is involved in the transmission of L. killicki. However, other mammals could constitute potential reservoir hosts in Tunisia and other North African countries. In order to explore the role of hedgehogs as potential reservoirs of leishmaniasis, specimens (N=6) were captured during July-November period in 2011-2013 in an SCL endemic area in El Kef region, North-Western Tunisia. Using morphological characteristics, all specimens were described and measured. Biopsies from liver, heart, kidney and spleen of each animal were used to extract genomic DNA, which was further used in PCR assays to assess the presence of Leishmania parasites. Different PCRs targeting kinetoplast minicircles, ITS1, mini-exon genes and a repetitive Leishmania- specific sequence, were applied. To further identify Leishmania species involved, RFLP analysis of amplified fragments was performed with appropriate restriction enzymes. Using morphological characters, animals were identified as North African hedgehogs, also called Algerian hedgehogs, that belong to the Erinaceidae family, genus Atelerix Pomel 1848, and species algirus (Lereboullet, 1842). PCR results showed in total that all specimens were Leishmania infected, with different organs incriminated, mainly liver and spleen. Results were confirmed by direct sequencing of amplified fragments. Species identification showed that all specimens were infected with L. major, three of which were additionally co-infected with L. infantum. The present study

  2. Immunity and immunosuppression in experimental visceral leishmaniasis

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    Goto H.

    2004-01-01

    Full Text Available Leishmaniasis is a disease caused by protozoa of the genus Leishmania, and visceral leishmaniasis is a form in which the inner organs are affected. Since knowledge about immunity in experimental visceral leishmaniasis is poor, we present here a review on immunity and immunosuppression in experimental visceral leishmaniasis in mouse and hamster models. We show the complexity of the mechanisms involved and differences when compared with the cutaneous form of leishmaniasis. Resistance in visceral leishmaniasis involves both CD4+ and CD8+ T cells, and interleukin (IL-2, interferon (IFN- gamma, and IL-12, the latter in a mechanism independent of IFN- gamma and linked to transforming growth factor (TGF-ß production. Susceptibility involves IL-10 but not IL-4, and B cells. In immune animals, upon re-infection, the elements involved in resistance are different, i.e., CD8+ T cells and IL-2. Since one of the immunopathological consequences of active visceral leishmaniasis in humans is suppression of T-cell responses, many studies have been conducted using experimental models. Immunosuppression is mainly Leishmania antigen specific, and T cells, Th2 cells and adherent antigen-presenting cells have been shown to be involved. Interactions of the co-stimulatory molecule family B7-CTLA-4 leading to increased level of TGF-ß as well as apoptosis of CD4+ T cells and inhibition of macrophage apoptosis by Leishmania infection are other components participating in immunosuppression. A better understanding of this complex immune response and the mechanisms of immunosuppression in experimental visceral leishmaniasis will contribute to the study of human disease and to vaccine development.

  3. Estudo da competência vetorial de Lutzomyia intermedia (Lutz & Neiva, 1912 para Leishmania (Viannia braziliensis, Vianna, 1911 Study of the vectorial competence of Lutzomyia intermedia (Lutz & Neiva, 1912 to Leishmania (Viannia braziliensis, Vianna, 1911

    Directory of Open Access Journals (Sweden)

    Antonio Carlos da Silva

    2001-04-01

    Full Text Available Estudou-se a competência vetorial de Lutzomyia intermedia (Diptera: Psychodidae do Vale do Ribeira (SP para estirpes de Leishmania (Viannia braziliensis (Kinetoplastida: Trypanosomatidae, mediante pesquisa de infectividade natural; exposições de fêmeas silvestres e colonizadas (F1 às lesões de hamsters experimentalmente infectados e testes de transmissão via picada. A infectividade natural e os testes de transmissão revelaram-se negativos e, nas exposições, foram obtidas positividades de 74% (123+/166 dissecados e 70% (115+/164 dissecados para fêmeas silvestres e colonizadas respectivamente, e o desenvolvimento das formas evolutivas compatíveis com o modelo Peripilaria. A suscetibilidade às estirpes testadas associada aos indicadores epidemiológicos concorrem para a suspeita do papel vetorial de Lutzomyia intermedia na região estudada.This paper investigated the vectorial competence of Lutzomyia intermedia (Diptera: Psychodidae in Vale do Ribeira (SP to strains of Leishmania (Viannia braziliensis (Kinetoplastida: Trypanosomatidae, by means of a search for natural infection; exposure of wild and colonized females (F1 to the lesions of experimentally infected hamsters and transmission tests by bite. The natural infection and the transmission tests were negative. In the exposures of Lu. intermedia to infected lesions we found rates of 74% (123+/166 dissected and 70% (115+/164 dissected for the wild and colonized females respectively. The development of the parasites was compatible with the development model of Peripilaria. The susceptibility of the tested strains associated with the epidemiological indicators contribute to the vectorial role suspicion of Lutzomyia intermedia in the studied region.

  4. Comparative genomics of Tunisian Leishmania major isolates causing human cutaneous leishmaniasis with contrasting clinical severity.

    Science.gov (United States)

    Ghouila, Amel; Guerfali, Fatma Z; Atri, Chiraz; Bali, Aymen; Attia, Hanene; Sghaier, Rabiaa M; Mkannez, Ghada; Dickens, Nicholas J; Laouini, Dhafer

    2017-06-01

    Zoonotic cutaneous leishmaniasis caused by Leishmania (L.) major parasites affects urban and suburban areas in the center and south of Tunisia where the disease is endemo-epidemic. Several cases were reported in human patients for which infection due to L. major induced lesions with a broad range of severity. However, very little is known about the mechanisms underlying this diversity. Our hypothesis is that parasite genomic variability could, in addition to the host immunological background, contribute to the intra-species clinical variability observed in patients and explain the lesion size differences observed in the experimental model. Based on several epidemiological, in vivo and in vitro experiments, we focused on two clinical isolates showing contrasted severity in patients and BALB/c experimental mice model. We used DNA-seq as a high-throughput technology to facilitate the identification of genetic variants with discriminating potential between both isolates. Our results demonstrate that various levels of heterogeneity could be found between both L. major isolates in terms of chromosome or gene copy number variation (CNV), and that the intra-species divergence could surprisingly be related to single nucleotide polymorphisms (SNPs) and Insertion/Deletion (InDels) events. Interestingly, we particularly focused here on genes affected by both types of variants and correlated them with the observed gene CNV. Whether these differences are sufficient to explain the severity in patients is obviously