To the Editor: Kala-azar (visceral leishmaniasis) is a fatal disease caused by a protozoan parasite Leishmania donovani and transmitted by the female sandfly, Phlebotomus argentipes. In the state of Assam, India, kala-azar epidemics occurred during 1875-1950 and resulted in thousands of deaths in the districts of Kamrup, Garo Hills, Goalpara, and Nagaon (1,2). The disease gradually disappeared from Assam because of the extensive use of DDT in the national malaria elimination program, and results of later entomologic studies indicated that there were no P. argentipes sandflies in this region after DDT use (3). However, sporadic kala-azar cases appeared again in Assam in 2004 (4), and in 2008, we reported a kala-azar outbreak in Kamrup (5), where kala-azar epidemics had occurred during the 1870s (1).. At bimonthly intervals during 2012, we conducted house-to-house surveys in 4 villages in the district of Kamrup, 845 households and 4,376 persons. Residents are socioeconomically poor and depend on ...
Visceral leishmaniasis, a lethal parasitic disease, is caused by the protozoan parasite Leishmania donovani. The absence of an effective vaccine, drug toxicity and parasite resistance necessitates the identification of novel drug targets. Reconstruction of genome-scale metabolic models and their simulation h
C-reactive protein (CRP) is an acute phase protein that binds to surface structures of a number of different organisms. Leishmania donovani express CRP ligand when first entering the mammalian host and CRP has been shown to alter macrophage function. The aim of this study was to investigate the functional significance of CRP-mediated uptake of L. donovani on survival of the parasite within human macrophages and macrophage cell responses to the infection. CRP opsonized L. donovani uptake was inhibitable by including excess CRP in the fluid phase, suggesting Fc receptor usage rather than indirect complement-mediated uptake. Comparing equivalent initial infection loads, parasite survival over 72 h within peripheral blood derived macrophages (PBMs) and differentiated U937 cells was unaltered by CRP. Whereas CRP increased macrophage responses to phosphorylcholine coated erythrocytes, no significant alteration in tumour necrosis factor-alpha, interleukin (IL)-10 or IL-12 production from PBMs was ...
We recently reported the production of the recombinant kinesin-related protein of Leishmania donovani with a molecular weight of 42 kd (rKRP42) and the value of the antigen in serum-based ELISA for the diagnosis of visceral leishmaniasis (VL). In this study, the rKRP42 antigen was validated with ELISA using urine samples (rKRP42 urine ELISA). The urine-based ELISA showed 94% sensitivity (108 positives among 115 VL samples) and 99.6% specificity (239 negatives among 240 non-VL samples). The sensitivity and specificity are almost similar to our previous results by ELISA with acetone-treated L. donovani promastigote antigen and direct agglutination test, both methods being done by use of urine samples. A comparison of the rKRP42 urine ELISA with the commercially available urinary antigen detection kit (KAtex) using 108 VL samples showed much higher sensitivity of the ELISA (96.3%) than KAtex (55.6%). The use of the rKRP42 antigen with urine samples will facilitate epidemiologic studies.
Intracellular infections, such as those caused by the protozoan parasite Leishmania donovani, a causative agent of visceral leishmaniasis (VL), require a potent host proinflammatory response for control. IL-17 has emerged as an important proinflammatory cytokine required for limiting growth of both extracellular and intracellular pathogens. However, there are conflicting reports on the exact roles for IL-17 during parasitic infections and limited knowledge about cellular sources and the immune pathways it modulates. We examined the role of IL-17 in an experimental model of VL caused by infection of C57BL/6 mice with L. donovani and identified an early suppressive role for IL-17 in the liver that limited control of parasite growth. IL-17-producing γδ T cells recruited to the liver in the first week of infection were the critical source of IL-17 in this model, and CCR2+ inflammatory monocytes were an important target for the suppressive effects of IL-17. Improved parasite control was independent ...
The gp63 encoding genes were characterized by PCRRFLP in 35 isolates representative of the Leishmania donovani complex (L. infantum, L. donovani, L. archibaldi and L. chagasi), with special attention to Mediterranean L. infantum from different geographical origins, and in separate groups from Old World Leishmania (L. major, L. tropica and L. aethiopica). The aim was to evaluate how the possible selective pressure by the host on these important surface proteins would influence structuring of our sample. Comparison was carried out with the structure obtained (i) from reported isoenzyme data, characters supposed to vary neutrally, and (ii) from PCRRFLP analysis of gp63 inter-genic regions, containing non-translated spacers and regulatory genes. Polymorphism within the gp63-encoding region, was much higher than in gp63 inter-genic regions. In the gp63 intra-genic dendrogram, the 4 species of L. donovani complex were discriminated and quite distinct from outgroups. Within L. infantum, geographical ...
immunity response against bacteria, fungi and parasites. Ill. The aim of this study was to know the immunological effects of polysaccharide extracted from Pseudomonas aeruginosa before and after the infection of BALB/c mice with Leishmania donovani in trial to provide a method for prevention of the disease in human.174 male BALB/c mice were divided into control and experimental groups with each group consisting of six animals. The experimental groups injected intraperitoneally [i. p] with 0.2 ml phosphate buffer saline [PBS] containing 1x108 parasite. Cerdain groups were injected intraperitoneally by polysaccharide [PS] at doses of 100, 150, 250 jug on day 3, 6, and daily for 6 days before infection with Leishmania donovani. These animals were sacrified after 8 weeks. Other groups were injected intraperitoneally with polysaccharides on day 7 post infection at the doses of 100, 150, 250, micro, 6 animals were sacrified after 2, 4, 6, 8 weeks. Total and differential count of leukocytes, ...
Currently there is no vaccine against visceral leishmaniasis (VL). Towards developing an effective vaccine, we have reported extensively on the immunogenicity of live attenuated LdCentrin-/- mutants in naive animal models. In VL endemic areas, asymptomatic carriers outnumber symptomatic cases of VL and are considered to be a reservoir of infection. Vaccination of asymptomatic cases represents a viable strategy to eliminate VL. Immunological correlates of protection thus derived might have limited applicability in conditions where the immunized host has prior exposure to virulent infection. To examine whether LdCen-/- parasites can induce protective immunity in experimental hosts that have low-level parasitemia from a previous exposure mimicking an asymptomatic condition, we infected C57Bl/6 mice with wild type Leishmania donovani parasites expressing LLO epitope (LdWTLLO 103, i.v.). After 3 weeks the mice with low levels of parasitemia were immunized with LdCen-/- parasites expressing 2W epitope (LdCen-
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Mice deficient in phagocyte oxidase (phox) and inducible nitric oxide synthase (iNOS), which are primary macrophage killing mechanisms, generated tissue granulomas but showed unrestrained Leishmania donovani visceral replication and suboptimal initial responsiveness to antimony treatment. Nevertheless, visceral infection was controlled post-treatment and did not recur. A phox/iNOS-independent macrophage mechanism, which was not triggered by L. donovani, emerges after chemotherapy.
Pentavalent antimonials (SbV) are the first line drug against leishmaniasis worldwide, but drug resistance is increasingly reported, particularly in the Indian sub-continent, where it represents a major threat for the control of anthroponotic visceral leishmaniasis (VL). In order to understand the epidemiological dynamics of antimonial resistance in anthroponotic VL, we analysed here the population structure of 24 Leishmania donovani stocks isolated from anthroponotic VL-patients from Eastern Nepal: 13 SbV-naturally resistant and 11 SbV-sensitive, as demonstrated by in vitro drug susceptibility assays. The parasites were genotyped by PCR-RFLP analysis of kDNA minicircles and by microsatellite analysis and the encountered polymorphism revealed a polyclonal structure among resistant isolates. Furthermore, analysis of paired samples obtained from the same patients before treatment and after failure revealed primary as well as acquired resistance. The hypothesis of independent events of drug ...
Leishmania is a group of trypanosomatid protozoan parasites that exist in two morphological forms: a promastigote form within their insect vector and an amastigote form in the mammalian host. To study gene expression in these two distinct lifecycle forms, real-time quantitative PCR (RT-qPCR) experiments were used to determine the copy number of control gene transcripts in the two lifecycle form populations. The goal of the current study was to clone the β-tubulin gene from Leishmania donovani and evaluate its role as a reference control for RT-qPCR gene expression studies.
BioAssay record AID 626318 submitted by ChEMBL: Antiparasitic activity against amastigotes of Leishmania donovani MHOM/ET/67/L82 infected in rat L6 cells after 72 hrs by by Alamar blue assay.
BioAssay record AID 731440 submitted by ChEMBL: Selectivity index, ratio of CC50 for human KB cells to IC50 for Leishmania donovani amastigote infected in mouse J774A.1 cells.
Four monoclonal antibodies (McAbs) were generated against the soluble extracellular acid phosphatase (EC 3.1.3.2) (S-AcP) of Leishmania donovani. These were detected in the primary screen using an ELISA with promastigote culture supernatants as antigen. Three of the McAbs demonstrated bound S-AcP from such culture supernatants in an enzyme activity binding assay. All immunoprecipitated metabolically labeled S-AcP but none showed any binding to the promastigote surface by indirect immunofluorescence. Moreover, none reacted with Triton X-100 solubilized plasma membranes by immunoprecipitation or Western blotting. These results demonstrated that the McAbs did not recognize the surface membrane bound acid phosphatase, but were specific for the extracellular soluble enzyme. Further, none of the antibodies immunoprecipitated any of the five human acid phosphatase isozymes or reacted with them in Western blots or the enzyme activity binding assay. Therefore, they are specific for the parasite-derived ...
The histopathological hallmark of hepatic resistance to visceralizing species of Leishmania is the development of functional granulomas [10, 11, 14]. Here we used IHC as a tool to characterise the different cells involved in the hepatic granuloma development at different stages of experimental VL in BALB/c mice, complemented by quantitative image analysis and detection of Leishmania antigen.. Immunohistochemical methods described here are a powerful tool to characterise host responses to infection in situ in mouse models of Leishmania spp. infection. These have also been used in other granulomatous diseases that share some, though not all properties with VL [15-18]. Additionally these techniques can be utilised to evaluate the cellular mechanism of new vaccines, drugs and treatment regimens [19-21]. Therefore this study provides in depth insights into the cellular dynamics of experimental VL in a context relevant to advancing health.. In agreement with previous studies [22, 23], we observed that ...
MAP kinases (MAPK) are the most downstream kinases in signal transduction cascades and regulate critical cellular activities such as cell proliferation, differentiation, mortality, stress response, and apoptosis. The Leishmania donovani MAPK1 (LdMAPK1) is involved in parasite viability and drug resistance, but its substrates have not been identified yet. Aiming to identify the possible targets(s) of LdMAPK1, we sought to isolate interacting partners by co-immunoprecipitation, gel electrophoresis and mass spectrometry. Out of fifteen analyzed protein bands, four were identified as subunits of the HSP90 foldosome complex, namely HSP 90, HSP70, STI and SGT. Western blot analysis not only confirmed that LdMAPK1 interacts with HSP70 and HSP90 but also demonstrated that MAPK1 abundance modulates their expression. The interaction is sensitive to treatment with AMTZD, a competitive ERK inhibitor. MAPK1 also displayed kinase activity with HSP90 or HSP70 as substrates. By phosphorylating HSPs in the ...
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Natural killer (NK) T cells are activated by synthetic or self-glycolipids and implicated in innate host resistance to a range of viral, bacterial, and protozoan pathogens. Despite the immunogenicity of microbial lipoglycans and their promiscuous binding to CD1d, no pathogen-derived glycolipid antigen presented by this pathway has been identified to date. In the current work, we show increased susceptibility of NK T cell-deficient CD1d−/− mice to Leishmania donovani infection and Leishmania-induced CD1d-dependent activation of NK T cells in wild-type animals. The elicited response was Th1 polarized, occurred as early as 2 h after infection, and was independent from IL-12. The Leishmania surface glycoconjugate lipophosphoglycan, as well as related glycoinositol phospholipids, bound with high affinity to CD1d and induced a CD1d-dependent IFNγ response in naive intrahepatic lymphocytes. Together, these data identify Leishmania surface glycoconjugates as potential glycolipid antigens and suggest an
Bates, P A and Dwyer, D M (1987) Biosynthesis and secretion of acid phosphatase by Leishmania donovani promastigotes. Molecular and Biochemical Parasitology, 26 (3). pp. 289-296. ISSN 0166-6851. Bates, P A and Kurtz, M K and Gottlieb, M and Dwyer, D M (1987) Leishmania donovani : generation of monospecific antibody reagents to soluble acid phosphatase. Experimental Parasitology, 64 (2). pp. 157-164. ISSN 0014-4894. Ikeda, S and Wong, C W and Allsop, D and Landon, M and Kidd, M and Glenner, G G (1987) Immunogold labeling of cerebrovascular and neuritic plaque amyloid fibrils in Alzheimers disease with an anti-β protein monoclonal antibody. Laboratory Investigation, 57 (4). pp. 446-9. ISSN 0023-6837. LAUDER, R M and BEYNON, A D (1987) LIPID HISTOCHEMISTRY OF RAT INCISOR DENTIN. Journal of Dental Research, 66 (4). p. 850. ISSN 0022-0345. ...
FIG. 1. Recombinant LdmPrx shows peroxiredoxin enzyme activities in vitro. (A) Twelve percent SDS-PAGE of purified rLdmPrx under reducing conditions. Molecular mass standards are indicated on the left. (B) Western blot assay of L. donovani promastigote lysates. Cells (5 × 106) from the stationary growth phase (6 × 107/ml) were lysed directly in hot SDS sample buffer under nonreducing conditions (without DTT) and reducing conditions (in the presence of 20 mM DTT). Blots were developed with anti-LdmPrx polyclonal antibodies. Molecular mass standards are indicated on the left. (C) Nicking assay with recombinant LdmPrx was performed as described in Materials and Methods. Samples were then loaded onto a 1% agarose gel. Lane 1, only DTT; lane 2, only FeCl3; lane 3, DTT plus FeCl3; lane 4, DTT plus FeCl3 plus rLdmPrx (0.5 μM); lane 5, DTT plus FeCl3 plus rLdmPrx (1 μM); lane 6, DTT plus FeCl3 plus rLdmPrx (2 μM); lane 7, DTT plus FeCl3 plus rLdmPrx (5 μM); lane 8, DTT plus FeCl3 plus bovine serum ...
TY - JOUR. T1 - Immunomodulatory effect of antigenic fractions of a recent clinical isolate of L. donovani on monocytic cell lines. AU - Tripathi, Parul. AU - Chandra, Dinesh. AU - Naik, Sita. PY - 2008. Y1 - 2008. N2 - Nitric oxide (NO) and cytokines are important mediators of the immune response to Leishmania. We have recently reported that following SDS-PAGE separation and transfer of whole L. donovani antigen (strain 2001, a recent clinical isolate from Bihar) into 11 fractions (named F1 to F11; MW range 139-24.2 Kd), only the high molecular weight (MW) fractions (F1 to F4; MW range 134-64.2 Kd) had immunostimulatory activity when tested in leishmania exposed immune individuals. The F1 to F11 fractions were able to induce significant proliferation of peripheral blood mononuclear cells (PBMCs) of leishmania exposed immune individuals and production of variable amounts of IFN-γ IL-12p40 and IL-10. The present study was undertaken to evaluate the effect of L. donovani promastigotes whole ...
Leishmaniasis is an parasitic infectious disease of dogs and people that is usually limited to tropical regions of the world, including South America, the Mediterranean, Middle East and Asia. The subspecies of the parasite Leishmania donovani can infect dogs, causing a disease form called visceral leishmaniasis. Dogs serve as a reservoir of infection. The disease is transmitted among dogs and to people by sandflies.. The disease was not thought to be naturally present in the United States. However, there have been cases in the United States in dogs that have traveled to areas where natural infection occurs. Sand fly species, presumably capable of transmitting the disease, are present in the United States creating the potential for the disease to increase in incidence. General interest in this disease has risen because of a recent outbreak of leishmaniasis diagnosed in several foxhounds in a kennel in New York. The kennel and kennel veterinarians are working with the Centers for Disease Control ...
Lipophosphoglycan (LPG) is the major glycoconjugate of Leishmania promastigote surface membrane. Previous studies on human and murine models have demonstrated that this molecule is involved in the attachment and survival of Leishmania in the host cells. Dog is the main reservoir of Leishmania strains responsible for human leishmaniasis in Italy. Since no studies have been performed on the LPG-canine phagocyte interactions, we investigated the LPG effects on dog phagocyte functions by evaluating: 1) the chemotactic activity of peripheral monocytes and polymorphonuclear (PMN) cells, in terms of cellular polarization; 2) the PMN cell respiratory burst, by measuring superoxide anion and hydrogen peroxide production. Results demonstrated a significant reduction of metabolic and chemotactic activity in LPG-preincubated cells, thus emphasizing the ability of this molecule to impair also the canine phagocyte responses. ...
The primary structure of the major surface glycoconjugate of Leishmania donovani parasites, a lipophosphoglycan, has been further characterized. The repeating PO4-6Galp beta 1-4Man disaccharide units, which are a salient feature of the molecule, are shown to terminate with one of several neutral structures, the most abundant of which is the branched trisaccharide Galp beta 1-4(Manp alpha 1-2)Man. The phosphosaccharide core of lipophosphoglycan, which links the disaccharide repeats to a lipid anchor, contains 2 phosphate residues. One of the core phosphates has previously been localized on O-6 of the galactosyl residue distal to the lipid anchor; the second phosphate is now shown to be on O-6 of the mannosyl residue distal to the anchor and to bear an alpha-linked glucopyranosyl residue. Also, the anomeric configuration of the unusual 3-substituted Galf residue in the phosphosaccharide core is established as beta. The complete structure of the core is thus PO4-6Galp alpha 1-6Galp alpha 1-3Galf ...
The primary structure of the major surface glycoconjugate of Leishmania donovani parasites, a lipophosphoglycan, has been further characterized. The repeating PO4-6Galp beta 1-4Man disaccharide units, which are a salient feature of the molecule, are shown to terminate with one of several neutral structures, the most abundant of which is the branched trisaccharide Galp beta 1-4(Manp alpha 1-2)Man. The phosphosaccharide core of lipophosphoglycan, which links the disaccharide repeats to a lipid anchor, contains 2 phosphate residues. One of the core phosphates has previously been localized on O-6 of the galactosyl residue distal to the lipid anchor; the second phosphate is now shown to be on O-6 of the mannosyl residue distal to the anchor and to bear an alpha-linked glucopyranosyl residue. Also, the anomeric configuration of the unusual 3-substituted Galf residue in the phosphosaccharide core is established as beta. The complete structure of the core is thus PO4-6Galp alpha 1-6Galp alpha 1-3Galf ...
Arun received his doctorate from University of Hyderabad, India. He worked on the molecular and immunological aspects of Leishmania donovani infection. He joined the Koshy lab as Postdoctoral research associate and will be working on transcriptional profiling of individual neurons which have interacted with Type II and Type III Toxoplasma parasites.. ...
Several novel type of lipopeptides were synthesized and evaluated for their ability to stimulate non-specific resistance against Leishmania donovaniinfection. Peritoneal macrophages isolated from...
The gene ORFF is part of the multigenic LD1 locus on chromosome 35 that is frequently amplified in Leishmania. The function of ORFF is unknown. The gene encoding ORFF was cloned into a eukaryotic expr...
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Filtering by: Creator Gayatri A. Vasudevan Remove constraint Creator: Gayatri A. Vasudevan Department Dept. of Biochemistry and Molecular Biology Remove constraint Department: Dept. of Biochemistry and Molecular Biology Keyword leishmania donovani Remove constraint Keyword: leishmania donovani School School of Medicine Remove constraint School: School of Medicine ...
Parasitic promastigotes that cause leishmaniosis in humans (Leishmania donovani), coloured scanning electron micrograph (SEM). This tropical disease is transmitted by bites from infected sand flies. They are ingested by the insect vector during a blood meal from a mammal or human. The parasites in humans are found within macrophages in the amastigote form. In the blood stream they transform into the promastigote form. Promastigotes multiple by longitudinal fission in the gut of the insect. Leishmaniosis occurs in two forms: cutaneous which affects the skin and mucous membranes, usually giving rise to an ulcer at the site of the insect bite. The more serious kala- azar causes fever and liver damage, and it can be fatal. Magnification: x1,000 when shortest axis printed at 25 millimetres. - Stock Image C032/0909
Hatásos a betegségeket, például maláriát okozó protozoonok ellen. Bizonyított, hogy gyógyszerimmunis protozoonok ellen is hatásos lehet.[14] Főzetét gégegyulladás enyhítésére használják.[15] A szíriai rutafű egy másik összetevője, a vasicin (peganin) a Leishmania donovani nevű, zsigeri leishmaniasist okozó protozoon ellenszere.[20] „A peganinhidrklorid-dihidrát úgy tűnik - amellett, hogy biztonságos - sejtelhalást okoz az L. donovani mindkét stádiumában a mitokondriális membránpotenciál csökkentésével."[21] A növény egy másik alkaloidája, a harmin „a sejten helüli paraziták elleni figyelemre méltó hatása, valamint májra és vesére egyaránt ártalmatlan természete miatt a harmin - kötött formáiban - emberek kezelésére is alkalmas lehet."[22] Egy tanulmány szerint a szíriai rutafű életmentő lehet a theileriosis-szal fertőzött marhák számára.[23] A betegség teljes állományokat is kiirthat: Afrikában 2007-ben 1,1 millió ...
Synthesis of oligosaccharides in our group stands on the protocols that we have developed over the last several years using gold catalysts. We can synthesize both 1,2-trans and 1,2-cis linkages of Mannopyranose in stereoselective fashion. Gold catalysis on propargyl 1,2-orthoesters results in 1,2-trans mannopyranosides with 2-O-ester moiety that can be saponified, oxidized and reduced to get the corresponding 1,2-cis mannopyranosides as shown in the synthesis of terminal tetrasaccharide cap of Leishmania donovani.. ...
Louzada-Junior, Paulo and Freitas, Max Victor Carioca Nota de preocupa o: Ahlin E et al., "Anticorpos antipept deos citrulinados e fator reumatoide em pacientes sudaneses com infec o por Leishmania donovani", Rev Bras Reumatol 2011; 51(6):572-86. Rev. Bras. Reumatol., Out 2012, vol.52, no.5, p.665-665. ISSN 0482- ...
TY - JOUR. T1 - Characterization of a mutant Leishmania donovani deficient in adenosine kinase activity. AU - Iovannisci, David M.. AU - Ullman, Buddy. PY - 1984/6. Y1 - 1984/6. N2 - From a mutagenized population of wildtype Leishmania donovani promastigotes, a clonal cell line, TUBA2, was isolated by virtue of its ability to survive and grow in 20 μM tubercidin (7-deazaadenosine). The TUBA2 clone was also 1000-fold less sensitive than the parental line to growth inhibition by formycin A, another cytotoxic adenosine analog. Parental and mutant cells, however, were equally sensitive to growth inhibition by formycin B, allopurinol riboside, and 6-thioguanosine. Mutant cell extracts, unlike those prepared from wildtype cells, did not phosphorylate radiolabelled adenosine, tubercidin, or formycin A. Intact adenosine kinase-deficient cells did not accumulate exogenous tubercidin or formycin A but incorporated [14C]adenosine at rates 25% of those found for parental cells. The uptake data suggest that ...
Leishmaniasis constitutes a complex of diseases with clinical and epidemiological diversity and includes visceral leishmaniasis, a disease that is fatal when left untreated. In earlier studies, the authors reported that Aloe vera leaf exudate (AVL) is a potent antileishmanial agent effective in promastigotes of Leishmania braziliensis, Leishmania mexicana, Leishmania tropica, Leishmania major and Leishmania infantum and also in axenic amastigotes of Leishmania donovani. In the present study, it has been demonstrated that, in promastigotes of L. donovani (IC50=110 μg ml−1), AVL mediates this leishmanicidal effect by triggering a programmed cell death. Incubation of promastigotes with AVL caused translocation of phosphatidylserine to the outer leaflet of the plasma membrane as measured by annexin V binding, which was accompanied by loss of mitochondrial membrane potential, release of cytochrome c into the cytosol and concomitant nuclear alterations that included chromatin condensation,
BACKGROUND Visceral leishmaniasis (VL or kala azar) is the most serious form of human leishmaniasis, responsible for over 20,000 deaths annually, and post kala azar dermal leishmaniasis (PKDL) is a stigmatizing skin condition that often occurs in patients after successful treatment for VL. Lack of effective or appropriately targeted cell mediated immunity, including CD8+ T cell responses, underlies the progression of VL and progression to PKDL, and can limit the therapeutic efficacy of anti-leishmanial drugs. Hence, in addition to the need for prophylactic vaccines against leishmaniasis, the development of therapeutic vaccines for use alone or in combined immuno-chemotherapy has been identified as an unmet clinical need. Here, we report the first clinical trial of a third-generation leishmaniasis vaccine, developed intentionally to induce Leishmania-specific CD8+ T cells. METHODS We conducted a first-in-human dose escalation Phase I trial in 20 healthy volunteers to assess the safety, tolerability and
Fatty acyl-CoA synthetase (fatty acid: CoA ligase, AMP-forming; (EC 6.2.1.3)) catalyzes the formation of fatty acyl-CoA by a two-step process that proceeds through the hydrolysis of pyrophosphate. Fatty acyl-CoA represents bioactive compounds that are involved in protein transport, enzyme activation, protein acylation, cell signaling, and transcriptional control in addition to serving as substrates for beta oxidation and phospholipid biosynthesis. Fatty acyl-CoA synthetase occupies a pivotal role in cellular homeostasis, particularly in lipid metabolism. Our interest in fatty acyl-CoA synthetase stems from the identification of this enzyme, long-chain fatty acyl-CoA ligase (LCFA) by microarray analysis. We found this enzyme to be differentially expressed by |i|Leishmania donovani|/i| amastigotes resistant to antimonial treatment. In the present study, we confirm the presence of long-chain fatty acyl-CoA ligase gene in the genome of clinical isolates of |i|Leishmania donovani|/i| collected from the
Leishmania donovani is the etiological agent of visceral leishmaniasis in the Indian sub-continent (ISC). Leishmania are Protozoa alternating between two life forms: the extracellular promastigotes in the insect vector and the intracellular amastigotes in the mammalian host. Pentavalent antimony was the first line drug in the ISC from 1923 to 2005 when it was abandoned because of treatment failure and drug resistance. In a previous phylogenomic study, we were able to show the circulation of two genetically different L. donovani in the ISC (i) the Core Group (CG) endemic in the Gangetic plains and (ii) another population called ISC1 found in the Nepalese high-lands. Interestingly, 100% of the CG isolates showed a unique ancestral character, the intra-chromosomal amplification (ICA) of the H- and M-loci. However, the link between the genomic features and drug resistance was not clear. The main hypothesis of this PhD was that gene dosage would play a major role in the development of antimonial ...
Leishmania donovani is the etiological agent of visceral leishmaniasis in the Indian sub-continent (ISC). Leishmania are Protozoa alternating between two life forms: the extracellular promastigotes in the insect vector and the intracellular amastigotes in the mammalian host. Pentavalent antimony was the first line drug in the ISC from 1923 to 2005 when it was abandoned because of treatment failure and drug resistance. In a previous phylogenomic study, we were able to show the circulation of two genetically different L. donovani in the ISC (i) the Core Group (CG) endemic in the Gangetic plains and (ii) another population called ISC1 found in the Nepalese high-lands. Interestingly, 100% of the CG isolates showed a unique ancestral character, the intra-chromosomal amplification (ICA) of the H- and M-loci. However, the link between the genomic features and drug resistance was not clear. The main hypothesis of this PhD was that gene dosage would play a major role in the development of antimonial ...
This study was carried out in clusters of villages that represent an endemic focus of visceral leishmaniasis (VL). These villages were located in Gedaref state, eastern Sudan. For diagnostic purposes polymerase chain reaction (PCR) was performed successfully, directly from clinical samples spotted on filter papers with no prior cultivation from 100 patients suspected of having kala-azar or post kala-azar dermal leishmaniasis. Mainly the ribosomal internal transcribed spacer (ITS1 & ITS2) were targeted in PCR because this region is more variable and allows clear species identification and also strain differences could be expected by further analysis of these PCR products. PCR was found to be more sensitive compared to the gold standard microscopic method. Four PCR based approaches were used to analyse diversity within Sudanese isolates of Leishmania donovani. Methods compared were fingerprinting with single non-specific primers, restriction analysis of the amplified ITS locus (RFLP), ...
The EtOH extract of Abrus schimperi (Fabaceae), collected in Kenya, demonstrated significant activity against Leishmania donovani promastigotes with IC50 value of 3.6 microg/mL. Bioassay-guided fractionation of CHCl3 fraction using Centrifugal Preparative TLC afforded two antiparasitic isoflavanquinones, namely amorphaquinone (1) and pendulone (2). They displayed IC50 values of 0.63 microg/mL and 0.43 microg/mL, respectively, against L. donovani promastigotes. Both the compounds were also evaluated against L. donovani axenic amastigotes and amastigotes in THPI macrophage cultures. In addition, compounds 1 and 2 showed antiplasmodial activity against Plasmodium falciparum D6 and W2 strains, while 2 displayed antibacterial activity against Staphylococcus aureus and methicillin-resistant S. aureus (each IC50 1.44 microg/mL). The 1H and 13C data of 1, not fully assigned previously, were unambiguously assigned using 1D and 2D NMR HMBC and HMQC experiments. In addition, the absolute stereochemistry of ...
Visceral leishmaniasis (VL) or kala-azar is the most dreaded and devastating formof leishmaniasis, causing high mortality rate, mainly in children. A vaccine againstdifferentforms ofleishmaniasis should be feasible considering the wealth of information on geneticsof the parasite, clinical and experimental immunology of leishmaniasis, andandbIO.lobgiylityof vaccines that can protect expenm. entaI arumaIsagainst challenge With the avallad here i ffectiL. hmaniaspecies. However, to ate, t ere ISno e ectivevaccine against anydifferenftleiesthsmaniasisfor general human use. Efforts to develop an effective vaccine soform 0e been limited due to lack of an appropriate adjuvant. A mixture of safe Leishmaniafar .ha:sandan adjuvant that preferentially stimulates cellular immune response presentsanug.e I option for a vacci.n e against Ie ishmam.asi.s, A vaccm. e for man needs to be testeda. rasnuoitnaableprimate models such as the vervet monkey due to their close phylogenetic~lation to humans. This study ...
Leishmaniasis is a neglected tropical parasitic diseases affecting millions of people around the globe. Quinazolines are a group of compounds with diverse pharmacological activities. Owing to their promising antileishmanial activities, some 3-aryl-2-(substitutedstyryl)-4(3H)-quinazolinones were synthesized in good yields (65.2% to 86.4%). The target compounds were synthesized by using cyclization, condensation, and hydrolysis reactions. The structures of the synthesized compounds were determined using elemental microanalysis, infrared (IR), and proton nuclear magnetic resonance (1H NMR). The in vitro antileishmanial activities of the synthesized compounds were evaluated using Leishmania donovani strain. All the synthesized compounds displayed appreciable antileishmanial activities (IC50 values, 0.0128 to 3.1085 μg/ml) as compared to the standard drug miltefosine (IC50 = 3.1911 μg/ml). (E)-2-(4-chlorostyryl)-3-p-tolyl-4(3H)-quinazolinone (7) is the compound with the most promising antileishmanial
Leishmaniasis is a severe infectious disease. Drugs used for leishmaniasis are very toxic, and no vaccine is available. We found that the hemoglobin receptor (HbR) of Leishmania was conserved across various strains of Leishmania, and anti-HbR antibody could be detected in kala-azar patients sera. Our results showed that immunization with HbR-DNA induces complete protection against virulent Leishmania donovani infection in both BALB/c mice and hamsters. Moreover, HbR-DNA immunization stimulated the production of protective cytokines like interferon-γ (IFN-γ), interleukin-12 (IL-12), and tumor necrosis factor-α (TNF-α) with concomitant down-regulation of disease-promoting cytokines like IL-10 and IL-4. HbR-DNA vaccination also induced a protective response by generating multifunctional CD4+ and CD8+ T cells. All HbR-DNA-vaccinated hamsters showed sterile protection and survived during an experimental period of 8 months. These findings demonstrate the potential of HbR as a vaccine candidate ...
Kala azar is the second largest parasitic killer in the world-only malaria is more deadly. Along with Chagas disease and sleeping sickness, kala azar is one of the most dangerous neglected tropical diseases (NTDs).
TY - JOUR. T1 - High efficiency plating method for Leishmania promastigotes in semidefined or completely-defined medium. AU - Iovannisci, D. M.. AU - Ullman, B.. PY - 1983/1/1. Y1 - 1983/1/1. N2 - A simple technique, developed for the isolation of clones derived from single, promastigote cells of Leishmania donovani and Leishmania tropica, involved the use of semisolid agar. Both species of Leishmania promastigotes formed discrete colonies at high efficiency either in semidefined medium containing 10% fetal calf serum or in completely-defined medium lacking serum. Visible colonies appeared between 8 and 14 days in growth medium containing 10% fetal calf serum. Replacement of the fetal calf serum with bovine serum albumin and Tween-80 increased the time of colony formation by 50% but did not affect the cloning efficiency. Viability of colonies transferred from semisolid agar to liquid suspension culture was 100%.. AB - A simple technique, developed for the isolation of clones derived from single, ...
Video articles in JoVE about infection control include Establishment and Characterization of UTI and CAUTI in a Mouse Model, A Parasite Rescue and Transformation Assay for Antileishmanial Screening Against Intracellular Leishmania donovani Amastigotes in THP1 Human Acute Monocytic Leukemia Cell Line, Infection of Zebrafish Embryos with Intracellular Bacterial Pathogens, Scalable High Throughput Selection From Phage-displayed Synthetic Antibody Libraries, Fecal Microbiota Transplantation via Colonoscopy for Recurrent C. difficile Infection, Generation of Recombinant Influenza Virus from Plasmid DNA, Flexible Colonoscopy in Mice to Evaluate the Severity of Colitis and Colorectal Tumors Using a Validated Endoscopic Scoring System, Rapid Molecular Detection and Differentiation of Influenza Viruses A and B, General Approach to the Physical Exam, Palpation, Investigating the Function of Deep Cortical and Subcortical Structures Using Stereotactic Electroencephalography: Lessons from the
Neutrophils, the essential components of the innate immune system, are recruited in large numbers to the pathogen site of entry. Several pathogens induce neutrophil autophagy; however, function of autophagic events during Leishmania parasite infection remain unknown. In this article, we report a finding that is new, to our knowledge, of how Leishmania-induced human polymorphonuclear neutrophil (hPMN) autophagy regulates the silent mode of parasite transfer to macrophages by influencing the engulfment of infected cells. Leishmania infection induced a time-dependent autophagy increase responsive to block by 3-methyladenine but sensitive to ULK1/2 inhibition only after 3 h. This suggested the prevalence of canonical autophagy during later hours, ULK1/2 inhibition being able to block only canonical autophagy. Interaction of Rubicon and Beclin-1 at 1 h postinfection affirmed the prevalence of noncanonical autophagy during early infection. There was a reduction in macrophage uptake of parasite-exposed ...