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1.
BMC Infect Dis ; 20(1): 946, 2020 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-33308170

RESUMO

BACKGROUND: Direct agglutination test (DAT) as a simple, accurate and reliable method, has been widely used for serodiagnosis of visceral leishmaniasis (VL) during the last three decades. The present study is a systematic review and meta-analysis to evaluate the diagnostic accuracy of DAT for serodiagnosis of human VL. METHODS: Electronic databases, including MEDLINE (via PubMed), SCOPUS, Web of Science, SID and Mag Iran (two Persian scientific search engines) were searched from December 2004 to April 2019. We determined the pooled sensitivity and specificity rates of DAT for the diagnosis of human VL, calculated positive and negative likelihood ratios (LR+ and LR-), and constructed summary receiver operating characteristic (ROC) curves parameters across the eligible studies. RESULTS: Of the 2928 records identified in the mentioned electronic databases and after examining reference lists of articles, 24 articles met inclusion criteria and were enrolled in the systematic review and out of them 20 records qualified for meta-analysis. The pooled sensitivity and specificity rates of DAT was 96% [95% CI, 92-98] and 95% [CI95% 86-99], respectively. The likelihood ratio of a positive test (LR+) was found to be 21 [CI95%, 6.6-66.5] and the likelihood ratio of a negative test (LR-) was found to be 0.04 [(CI95%, 0.02-0.08]. The combined estimate of the diagnostic odds ratio for DAT was high [467 (CI95%, 114-1912]). We found that the summary receiver operating characteristic curve (SROC) is positioned near the upper left corner of the curve and the area under curve (AUC) was 0.98 (95% CI, 0.97 to 0.99). CONCLUSION: Referring to our analysis, we determined that DAT can be considered as a valuable tool for the serodiagnosis of human VL with high sensitivity and specificity. As DAT is a simple, accurate and efficient serological test, it can be recommended for serodiagnosis of human VL particularly in endemic areas.


Assuntos
Testes de Aglutinação/métodos , Confiabilidade dos Dados , Leishmania donovani/imunologia , Leishmaniose Visceral/diagnóstico , Humanos , Leishmaniose Visceral/parasitologia , Razão de Chances , Curva ROC , Sensibilidade e Especificidade
2.
PLoS Pathog ; 16(12): e1009136, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33370418

RESUMO

The level of CD40 expression on dendritic cells (DCs) plays a decisive role in disease protection during Leishmania donovani (LD) infection. However, current understanding of the molecular regulation of CD40 expression remains elusive. Using molecular, cellular and functional approaches, we identified a role for Runx1 and Runx3 transcription factors in the regulation of CD40 expression in DCs. In response to lipopolysaccharide (LPS), tumor necrosis factor alpha (TNFα) or antileishmanial drug sodium antimony gluconate (SAG), both Runx1 and Runx3 translocated to the nucleus, bound to the CD40 promoter and upregulated CD40 expression on DCs. These activities of Runx proteins were mediated by the upstream phosphatidylinositol 3-kinase (PI3K)-Akt pathway. Notably, LD infection attenuated LPS- or TNFα-induced CD40 expression in DCs by inhibiting PI3K-Akt-Runx axis via protein tyrosine phosphatase SHP-1. In contrast, CD40 expression induced by SAG was unaffected by LD infection, as SAG by blocking LD-induced SHP-1 activation potentiated PI3K-Akt signaling to drive Runx-mediated CD40 upregulation. Adoptive transfer experiments further showed that Runx1 and Runx3 play a pivotal role in eliciting antileishmanial immune response of SAG-treated DCs in vivo by promoting CD40-mediated type-1 T cell responses. Importantly, antimony-resistant LD suppressed SAG-induced CD40 upregulation on DCs by blocking the PI3K-Akt-Runx pathway through sustained SHP-1 activation. These findings unveil an immunoregulatory role for Runx proteins during LD infection.


Assuntos
Antígenos CD40/imunologia , Subunidades alfa de Fatores de Ligação ao Core/imunologia , Células Dendríticas/imunologia , Regulação da Expressão Gênica/imunologia , Leishmaniose Visceral/imunologia , Animais , Antígenos CD40/biossíntese , Cricetinae , Humanos , Leishmania donovani/imunologia , Camundongos , Camundongos Endogâmicos BALB C
3.
Am J Trop Med Hyg ; 103(5): 1927-1929, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32959758

RESUMO

Visceral leishmaniasis (VL) is a systemic infection caused by the protozoal parasite Leishmania, spread via the bloodstream to the reticuloendothelial system, through the bite of the sand fly. It is endemic in parts of Africa, South America, Asia, and Europe, including the Mediterranean. Here, we describe a case of VL that was initially diagnosed as Q fever based on positive Coxiella burnetii serology and showed a partial response to doxycycline treatment.


Assuntos
Coxiella burnetii/imunologia , Doxiciclina/uso terapêutico , Leishmania donovani/imunologia , Leishmaniose Visceral/diagnóstico por imagem , Abdome/diagnóstico por imagem , Animais , Diagnóstico Diferencial , Hepatomegalia/diagnóstico por imagem , Humanos , Leishmania donovani/isolamento & purificação , Leishmaniose Visceral/tratamento farmacológico , Leishmaniose Visceral/parasitologia , Masculino , Febre Q/diagnóstico por imagem , Esplenomegalia/diagnóstico por imagem , Tórax/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Adulto Jovem
4.
PLoS One ; 15(9): e0238840, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32925980

RESUMO

Diagnosis of visceral leishmaniasis (VL) relies on invasive and risky aspirate procedures, and confirmation of cure after treatment is unreliable. Detection of Leishmania donovani antigens in urine has the potential to provide both a non-invasive diagnostic and a test of cure. We searched for L. donovani antigens in urine of VL patients from India and Sudan to contribute to the development of urine antigen capture immunoassays. VL urine samples were incubated with immobilised anti-L. donovani polyclonal antibodies and captured material was eluted. Sudanese eluted material and concentrated VL urine were analysed by western blot. Immunocaptured and immunoreactive material from Indian and Sudanese urine was submitted to mass spectrometry for protein identification. We identified six L. donovani proteins from VL urine. Named proteins were 40S ribosomal protein S9, kinases, and others were hypothetical. Thirty-three epitope regions were predicted with high specificity in the 6 proteins. Of these, 20 were highly specific to Leishmania spp. and are highly suitable for raising antibodies for the subsequent development of an antigen capture assay. We present all the identified proteins and analysed epitope regions in full so that they may contribute to the development of non-invasive immunoassays for this deadly disease.


Assuntos
Anticorpos Antiprotozoários/urina , Antígenos de Protozoários/urina , Leishmania donovani/imunologia , Leishmaniose Visceral/diagnóstico , Proteínas de Protozoários/urina , Adulto , Anticorpos Antiprotozoários/imunologia , Anticorpos Antiprotozoários/isolamento & purificação , Antígenos de Protozoários/imunologia , Antígenos de Protozoários/isolamento & purificação , Estudos de Casos e Controles , Humanos , Índia/epidemiologia , Leishmania donovani/isolamento & purificação , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/urina , Proteínas de Protozoários/imunologia , Proteínas de Protozoários/isolamento & purificação
5.
Am J Trop Med Hyg ; 103(5): 1938-1941, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32815498

RESUMO

Interleukin-10 (IL-10) and interleukin-27 (IL-27) both exert counterregulatory immunodeactivation in visceral Leishmania donovani infection. We studied experimental L. donovani infection in the livers of IL-10-/- and IL-27Rα-/- mice and observed that in IL-27Rα-/-, but not IL-10-/- mice, interferon-gamma (IFN-γ) and tumor necrosis factor (TNF) were required for heightened granulomatous inflammation and accelerated control of intracellular parasite replication. This difference in mechanism, along with residual IL-10 activity in IL-27Rα-/- mice, suggested targeting IL-27 in addition to IL-10 in a macrophage-activating, anti-counterregulatory cytokine treatment strategy. In C57BL/6 wild-type mice with established liver infection, a single injection of anti-IL-27 p28 or anti-IL-10R monoclonal antibody enhanced granuloma assembly, enabled macrophage activation, and induced comparable parasite killing (49-56%). However, anti-IL-27 p28 plus anti-IL-10R combination treatment did not increase leishmanicidal effects. These results suggest that IL-27 and IL-10 may operate in a linked deactivating mechanism and that in this intracellular infection, either IL-27 or IL-10 is a suitable immunotherapeutic target.


Assuntos
Interleucina-10/metabolismo , Interleucinas/metabolismo , Leishmania donovani/imunologia , Leishmaniose Visceral/tratamento farmacológico , Animais , Citocinas/imunologia , Modelos Animais de Doenças , Feminino , Humanos , Leishmaniose Visceral/parasitologia , Leishmaniose Visceral/patologia , Fígado/imunologia , Fígado/parasitologia , Fígado/patologia , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos C57BL
6.
Parasite Immunol ; 42(9): e12732, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32418227

RESUMO

Visceral leishmaniasis (VL) is caused by a protozoan parasite Leishmania donovani mainly influencing the population of tropical and subtropical regions across the globe. The arsenal of drugs available is limited, and prolonged use of such drugs makes parasite to become resistant. Therefore, it is very imperative to develop a safe, cost-effective and inexpensive vaccine against VL. Although in recent years, many strategies have been pursued by researchers, so far only some of the vaccine candidates reached for clinical trial and more than half of them are still in pipeline. There is now a broad consent among Leishmania researchers that the perseverance of parasite is very essential for eliciting a protective immune response and may perhaps be attained by live attenuated parasite vaccination. For making a live attenuated parasite, it is very essential to ensure that the parasite is deficient of virulence and should further study genetically modified parasites to perceive the mechanism of pathogenesis. So it is believed that in the near future, a complete understanding of the Leishmania genome will explore clear strategies to discover a novel vaccine. This review describes the need for a genetically modified live attenuated vaccine against VL, and obstacles associated with its development.


Assuntos
Leishmania donovani/imunologia , Vacinas contra Leishmaniose/imunologia , Leishmaniose Visceral/prevenção & controle , Animais , Humanos , Leishmania donovani/patogenicidade , Leishmaniose Visceral/imunologia , Vacinas Atenuadas/imunologia
7.
Parasit Vectors ; 13(1): 196, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32295617

RESUMO

BACKGROUND: Visceral leishmaniasis (VL) caused by dimorphic Leishmania species is a parasitic disease with high socioeconomic burden in endemic areas worldwide. Sustaining control of VL in terms of proper and prevailing immunity development is a global necessity amid unavailability of a prophylactic vaccine. Screening of experimental proteome of the human disease propagating form of Leishmania donovani (amastigote) can be more pragmatic for in silico mining of novel vaccine candidates. METHODS: By using an immunoinformatic approach, CD4+ and CD8+ T cell-specific epitopes from experimentally reported L. donovani proteins having secretory potential and increased abundance in amastigotes were screened. A chimera linked with a Toll-like receptor 4 (TLR4) peptide adjuvant was constructed and evaluated for physicochemical characteristics, binding interaction with TLR4 in simulated physiological condition and the trend of immune response following hypothetical immunization. RESULTS: Selected epitopes from physiologically important L. donovani proteins were found mostly conserved in L. infantum, covering theoretically more than 98% of the global population. The multi-epitope chimeric vaccine was predicted as stable, antigenic and non-allergenic. Structural analysis of vaccine-TLR4 receptor docked complex and its molecular dynamics simulation suggest sufficiently stable binding interface along with prospect of non-canonical receptor activation. Simulation dynamics of immune response following hypothetical immunization indicate active and memory B as well as CD4+ T cell generation potential, and likely chance of a more Th1 polarized response. CONCLUSIONS: The methodological approach and results from this study could facilitate more informed screening and selection of candidate antigenic proteins for entry into vaccine production pipeline in future to control human VL.


Assuntos
Antígenos de Protozoários/imunologia , Epitopos de Linfócito T/imunologia , Leishmania donovani/imunologia , Vacinas contra Leishmaniose/imunologia , Adjuvantes Imunológicos/química , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Biologia Computacional , Leishmania infantum/imunologia , Leishmaniose Visceral/parasitologia , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Proteômica , Proteínas de Protozoários/imunologia , Vacinas de Subunidades/imunologia
8.
Sci Rep ; 10(1): 4689, 2020 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-32170135

RESUMO

Visceral leishmaniasis is an infectious parasitic disease caused by the protozoan parasites Leishmania donovani and Leishmania infantum. The drugs currently used to treat visceral leishmaniasis suffer from toxicity and the emergence of parasite resistance, and so a better solution would be the development of an effective subunit vaccine; however, no approved vaccine currently exists. The comparative testing of a large number of vaccine candidates requires a quantitative and reproducible experimental murine infection model, but the parameters that influence infection pathology have not been systematically determined. To address this, we have established an infection model using a transgenic luciferase-expressing L. donovani parasite and longitudinally quantified the infections using in vivo bioluminescent imaging within individual mice. We examined the effects of varying the infection route, the site of adjuvant formulation administration, and standardised the parasite preparation and dose. We observed that the increase in parasite load within the liver during the first few weeks of infection was directly proportional to the parasite number in the initial inoculum. Finally, we show that immunity can be induced in pre-exposed animals that have resolved an initial infection. This murine infection model provides a platform for systematic subunit vaccine testing against visceral leishmaniasis.


Assuntos
Modelos Animais de Doenças , Leishmania donovani/imunologia , Vacinas contra Leishmaniose/imunologia , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/parasitologia , Camundongos Transgênicos , Animais , Progressão da Doença , Vacinas contra Leishmaniose/administração & dosagem , Leishmaniose Visceral/patologia , Leishmaniose Visceral/prevenção & controle , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Camundongos , Camundongos Knockout
9.
J Immunol Methods ; 480: 112765, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32119888

RESUMO

The performance of distinct serological tests (rK39-ICT, IFAT, DAT-LPC, FC-Simplex IgG1) was assessed and a laboratorial algorithm was proposed for accurate diagnosis of VL. DAT-LPC and FC-Simplex IgG1 showed outstanding accuracy (AUC = 0.93) to identify VL patients. The use of a sequential serological algorithm (rK39-ICT screening followed by DAT-LPC or FC-Simplex IgG1) improved the global accuracy for VL (97.2%) diagnosis. An alternative approach for diagnosis of VL has been also assessed for interchangeable use of serum/whole blood lysate samples in DAT-LPC and FC-Simplex IgG1. Our data showed an outstanding agreement for the results obtained with whole blood lysate samples as compared to serum samples (DAT-LPC =100%; FC-Simplex IgG1 = 99%). Together, these findings provide insights to improve the current overall accuracy of VL diagnosis and present innovative laboratorial tests and alternative samples from use in public health services.


Assuntos
Algoritmos , Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/imunologia , Imunoglobulina G/sangue , Leishmania donovani/imunologia , Leishmaniose Visceral/diagnóstico , Kit de Reagentes para Diagnóstico , Testes Sorológicos , Adolescente , Adulto , Idoso , Biomarcadores/sangue , Brasil , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Citometria de Fluxo , Interações Hospedeiro-Parasita , Humanos , Lactente , Leishmaniose Visceral/sangue , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/parasitologia , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Adulto Jovem
10.
Sci Rep ; 10(1): 3523, 2020 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-32103111

RESUMO

Visceral leishmaniasis is characterized by mixed production of Th1/2 cytokines and the disease is established by an enhanced level of Th2 cytokine. CD4+ T cells are main cell type which produces Th1/2 cytokine in the host upon Leishmania infection. However, the regulatory mechanism for Th1/2 production is not well understood. In this study, we co-cultured mice CD4+ T cells with Leishmania donovani infected and uninfected macrophage for the identification of dysregulated miRNAs in CD4+ T cells by next-generation sequencing. Here, we identified 604 and 613 known miRNAs in CD4+ T cells in control and infected samples respectively and a total of only 503 miRNAs were common in both groups. The expression analysis revealed that 112 miRNAs were up and 96 were down-regulated in infected groups, compared to uninfected control. Nineteen up-regulated and 17 down-regulated miRNAs were statistically significant (p < 0.05), which were validated by qPCR. Further, using insilco approach, we identified the gene targets of significant miRNAs on the basis of CD4+ T cell biology. Eleven up-regulated miRNAs and 9 down-regulated miRNAs were associated with the cellular immune responses and Th1/2 dichotomy upon Leishmania donovani infection. The up-regulated miRNAs targeted transcription factors that promote differentiation of CD4+ T cells towards Th1 phenotype. While down-regulated miRNAs targeted the transcription factors that facilitate differentiation of CD4+ T cells towards Th2 populations. The GO and pathway enrichment analysis also showed that the identified miRNAs target the pathway and genes related to CD4+ T cell biology which plays important role in Leishmania donovani infection.


Assuntos
Regulação da Expressão Gênica/imunologia , Leishmania donovani/imunologia , Leishmaniose Visceral/imunologia , MicroRNAs/imunologia , Células Th1/imunologia , Células Th2/imunologia , Animais , Feminino , Camundongos , Camundongos Endogâmicos BALB C
11.
Parasite Immunol ; 42(4): e12699, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31976563

RESUMO

In a bid to develop a novel immunoprophylactic measure against visceral leishmaniasis (VL), MHC class-II-restricted epitopes of LdODC were identified by reverse vaccinology approach. Five consensus HLA-DRB1*0101-restricted epitopes were screened. The analysis revealed that the set of epitopes was presented by at least 54 diverse MHC class-II alleles. Based on in silico screening, followed by molecular dynamics simulation, population coverage analysis, and HLA cross-presentation ability, five best epitopes were evaluated. PBMCs isolated from treated VL subjects, when stimulated with synthetic peptide alone or as a cocktail of peptides, triggered a secretory IFN-γ, but not the IL-10 level. Support in this notion came from intracellular cytokine level with a considerable up-regulated IFN-γ produced by CD4+ T cells. Also, the enhanced IFN-γ seemed to be augmented with the activation of macrophages with prominent IL-12 production. Therefore, it can be concluded that the screened MHC class-II-restricted epitope hotspots derived from Leishmania ODC can trigger CD4+ T cells, which can skew macrophage functions towards protection. However, a detailed analysis can explore its potentiality as a vaccine candidate.


Assuntos
Leishmania donovani/imunologia , Vacinas contra Leishmaniose/imunologia , Leishmaniose Visceral/imunologia , Ornitina Descarboxilase/imunologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Citocinas/imunologia , Epitopos de Linfócito T/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Humanos , Interleucina-10/imunologia , Leishmania donovani/enzimologia , Vacinas de Subunidades/imunologia
12.
Lancet Glob Health ; 8(2): e237-e243, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31981555

RESUMO

BACKGROUND: Nepal launched a visceral leishmaniasis (also known as kala-azar) elimination initiative in 2005. We primarily aimed to assess whether transmission of Leishmania donovani had decreased since the launch of the initiative. We also assessed the validity of the direct agglutination test (DAT) as a marker of infection, in view of future surveillance systems. METHODS: We did a repeat survey in a population aged 2 years and older for whom baseline serological data were available from 2006. Data were from three districts in the eastern region of Nepal. The primary outcome of interest was prevalent infection with L donovani as measured with DAT (cutoff value ≥1:3200). We compared age group-specific and cluster-specific seroprevalences in 2016 with those in 2006, using χ2 tests, with a specific focus on the comparison of seroprevalences in children born between 1996 and 2005, and those born between 2006 and 2015. To estimate the overall adjusted risk ratio for being seropositive in 2016 compared with 2006, we fitted a Poisson model controlling for age, sex, and cluster. FINDINGS: Between Oct 17, 2016, and Dec 26, 2016, we assessed 6609 individuals. DAT prevalence in children younger than 10 years was 4·1% (95% CI 3·2-5·4) in 2006 versus 0·5% (0·1-1·7) in 2016 (p<0·0001). Seroprevalence was lower in 2016 than in 2006 in all age groups and in all repeated clusters. The overall adjusted risk ratio of being seropositive was 0·44 (95% CI 0·37-0·52) for 2016 compared with 2006, and 0·04 (0·01-0·16) in children younger than 10 years. INTERPRETATION: Our findings show that transmission of L donovani in Nepal has decreased significantly between 2006 and 2016, coinciding with the elimination programme. DAT seems useful for monitoring of L donovani transmission. FUNDING: The Directorate-General for Development Cooperation of Belgium.


Assuntos
Erradicação de Doenças/estatística & dados numéricos , Erradicação de Doenças/tendências , Doenças Endêmicas/prevenção & controle , Leishmania donovani/imunologia , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/prevenção & controle , Leishmaniose Visceral/transmissão , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Doenças Endêmicas/estatística & dados numéricos , Feminino , Previsões , Humanos , Masculino , Pessoa de Meia-Idade , Nepal/epidemiologia , Fatores de Risco , Estudos Soroepidemiológicos , Inquéritos e Questionários , Adulto Jovem
13.
Parasitol Int ; 74: 101997, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31626986

RESUMO

B-cell activating factor (BAFF) is known as a cytokine responsible for survival and activation of B cells. However, involvement of the molecule in IgG antibody production during infection remains elusive. In this study, dependency of antibody production in Leishmania infection on BAFF was examined by using BAFF-knockout (BAFF-KO) mice. When BAFF-KO mice were infected with L. major, there was no significant difference in lesion development or parasite burden from those in infected wildtype mice. In contrast, levels of IgG antibodies to Leishmania crude antigen were lower in BAFF-KO mice, suggesting that antibody production during L. major infection is BAFF-dependent. ELISA using defined leishmanial antigens demonstrated that the influence of BAFF on antibody production during L. major varies depending on antigens; IgG production to tandem repeat proteins were more affected by BAFF than non-repeat antigens. On the contrary, all of the defined antigens tested were strongly affected by BAFF for IgG antibody production during L. donovani infection. These results suggest degree of BAFF contribution to antibody production during infection is variable depending on the type of infection and even on the type of antigen in a given infection. These results may explain contradictory roles of BAFF in antibody production in previous works.


Assuntos
Anticorpos Antiprotozoários/imunologia , Fator Ativador de Células B/imunologia , Imunoglobulina G/imunologia , Leishmaniose/imunologia , Animais , Antígenos de Protozoários/imunologia , Fator Ativador de Células B/genética , Feminino , Leishmania donovani/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout
14.
Parasite Immunol ; 42(1): e12678, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31610026

RESUMO

Dominant-negative mutation of LdeK1 gene, an eIF2α kinase from Leishmania donovani, revealed its role in translation regulation in response to nutrient starvation earlier. However, whether the kinase influences the infectivity of the parasites which naturally encounters nutrient deprivation during its life cycle was interesting to investigate. Both in vitro and in vivo experiments resulted in decrease of the parasite burden in peritoneal macrophages and in splenic/ hepatic load, respectively. An insight into the immune response of mice infected with mutant parasite showed enhanced pro-inflammatory cytokines and nitric oxide levels but reduced TH 2 and Treg population. The significantly reduced loss of infectivity of the parasites lacking a functional LdeK1 by modulating the immune response towards host protection makes it a potential vaccine candidate against Leishmaniasis.


Assuntos
Leishmania donovani/genética , Leishmania donovani/patogenicidade , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/parasitologia , eIF-2 Quinase/genética , Animais , Citocinas/imunologia , Feminino , Imunidade Celular , Leishmania donovani/imunologia , Fígado/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Óxido Nítrico/metabolismo , Carga Parasitária , Baço/imunologia , Baço/parasitologia , Linfócitos T/imunologia , Virulência
15.
Infect Disord Drug Targets ; 20(4): 461-466, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31203810

RESUMO

BACKGROUND: Visceral leishmaniasis (VL) is an emerging zoonosis disease that is endemic in the northwestern and southern part of Iran. This study aimed to evaluate the clinical characteristics and laboratory findings of the children with VL hospitalized at Children Medical Center Hospital (CMC), Tehran, Iran. METHODS: A retrospective study was performed based on studied medical records of children with a final diagnosis of VL from 2011 to 2016. For each patient's demographics, clinical laboratory findings and treatment were examined. RESULTS: The clinical features of 17 children were examined and the most frequent symptoms were fever (94.1%, n=16), pallor, loss of appetite (76.5%, n=13), splenomegaly (82.4%, n=14) and hepatomegaly (58.8%, n=10). The most frequent laboratory abnormalities were hematological including anemia (94.1%, n=16), leukopenia (52.9%, n=9) and thrombocytopenia (70.5%, n=12). In order to detect anti-Leishmania antibodies, DAT was performed in 11 patients and 82% of them were positive (titers ≥ 1: 3200). In addition, rK39 was used in 9 cases and 7 children (78%) had positive results. Direct parasitology revealed the presence of amastigotes of Leishmania in bone marrow aspirate (BMA) stained by Giemsa stain in 9 patients (69%, among 13 children). CONCLUSION: Leishmaniasis is a regional disease therefore management and control of disease, particularly in an endemic area, as well as detection of new emerging foci are recommended.


Assuntos
Anticorpos Antiprotozoários/metabolismo , Medula Óssea/parasitologia , Leishmania donovani/imunologia , Leishmaniose Visceral/diagnóstico , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Irã (Geográfico) , Leishmaniose Visceral/imunologia , Tempo de Internação , Masculino , Estudos Retrospectivos
16.
Parasite Immunol ; 42(2): e12687, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31770453

RESUMO

AIMS: This study aimed at evaluating the DNA vaccination efficacy of Leishmania major-derived MAPK10 against Leishmania donovani infection. METHODS AND RESULTS: MAPK10 is one of the 15 mitogen-activated protein kinases (MAPKs) of Leishmania major. Herein, we expressed the gene through a mammalian vector and tested whether priming with this gene would offer protection against L donovani infection. We report that LmjMAPK10 DNA vaccination using a mammalian expression vector significantly reduces the parasite burden. The protection is accompanied by host-protective T-cell functions, TH 1-type cytokines and elevated leishmanial antigen-specific IgG2a isotype response. T-cell response to the L donovani/challenge infection is associated with increase in IL-12 and IFN-γ, but reduced IL-10 and IL-4 production. CONCLUSIONS: LmjMAPK10 is cross-protective against L donovani infection.


Assuntos
Leishmania donovani/imunologia , Vacinas contra Leishmaniose/imunologia , Leishmaniose Visceral/prevenção & controle , Proteína Quinase 10 Ativada por Mitógeno/imunologia , Proteínas de Protozoários/imunologia , Vacinas de DNA/imunologia , Animais , Anticorpos Antiprotozoários/imunologia , Humanos , Imunoglobulina G/imunologia , Interferon gama/biossíntese , Interleucina-10/biossíntese , Subunidade p35 da Interleucina-12/biossíntese , Interleucina-4/biossíntese , Leishmania donovani/genética , Leishmaniose Visceral/imunologia , Macrófagos/imunologia , Macrófagos/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Proteína Quinase 10 Ativada por Mitógeno/genética , Proteínas de Protozoários/administração & dosagem , Proteínas de Protozoários/genética , Células Th1/imunologia
17.
PLoS One ; 14(12): e0225588, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31841511

RESUMO

Macrophages can reprogram their metabolism in response to the surrounding stimuli, which affects their capacity to kill intracellular pathogens. We have investigated the metabolic and immune status of human macrophages after infection with the intracellular trypanosomatid parasites Leishmania donovani, L. amazonensis and T. cruzi and their capacity to respond to a classical polarizing stimulus (LPS and IFN-γ). We found that macrophages infected with Leishmania preferentially upregulate oxidative phosphorylation, which could be contributed by both host cell and parasite, while T. cruzi infection did not significantly increase glycolysis or oxidative phosphorylation. Leishmania and T. cruzi infect macrophages without triggering a strong inflammatory cytokine response, but infection does not prevent a potent response to LPS and IFN-γ. Infection appears to prime macrophages, since the cytokine response to activation with LPS and IFN-γ is more intense in infected macrophages compared to uninfected ones. Metabolic polarization in macrophages can influence infection and immune evasion of these parasites since preventing macrophage cytokine responses would help parasites to establish a persistent infection. However, macrophages remain responsive to classical inflammatory stimuli and could still trigger inflammatory cytokine secretion by macrophages.


Assuntos
Doença de Chagas/imunologia , Citocinas/metabolismo , Leishmaniose/imunologia , Ativação de Macrófagos , Macrófagos/imunologia , Células 3T3 , Animais , Células Cultivadas , Doença de Chagas/sangue , Doença de Chagas/parasitologia , Citocinas/imunologia , Voluntários Saudáveis , Humanos , Leishmania donovani/imunologia , Leishmania donovani/isolamento & purificação , Leishmania mexicana/imunologia , Leishmania mexicana/isolamento & purificação , Leishmaniose/sangue , Leishmaniose/parasitologia , Macrófagos/metabolismo , Metaboloma/imunologia , Camundongos , Fosforilação Oxidativa , Cultura Primária de Células , Trypanosoma cruzi/imunologia , Trypanosoma cruzi/isolamento & purificação , Regulação para Cima
18.
Artigo em Inglês | MEDLINE | ID: mdl-31737574

RESUMO

Liposomes containing phosphatidylserine (PS) has been used for the delivery of drugs into the intramacrophage milieu. Leishmania (L.) infantum parasites live inside macrophages and cause a fatal and neglected viscerotropic disease, with a toxic treatment. Sertraline was studied as a free formulation (SERT) and also entrapped into phosphatidylserine liposomes (LP-SERT) against intracellular amastigotes and in a murine model of visceral leishmaniasis. LP-SERT showed a potent activity against intracellular amastigotes with an EC50 value of 2.5 µM. The in vivo efficacy of SERT demonstrated a therapeutic failure. However, when entrapped into negatively charged liposomes (-58 mV) of 125 nm, it significantly reduced the parasite burden in the mice liver by 89% at 1 mg/kg, reducing the serum levels of the cytokine IL-6 and upregulating the levels of the chemokine MCP-1. Histopathological studies demonstrated the presence of an inflammatory infiltrate with the development of granulomas in the liver, suggesting the resolution of the infection in the treated group. Delivery studies showed fluorescent-labeled LP-SERT in the liver and spleen of mice even after 48 h of administration. This study demonstrates the efficacy of PS liposomes containing sertraline in experimental VL. Considering the urgent need for VL treatments, the repurposing approach of SERT could be a promising alternative.


Assuntos
Antiprotozoários/administração & dosagem , Leishmania donovani/efeitos dos fármacos , Leishmaniose Visceral/tratamento farmacológico , Leishmaniose Visceral/parasitologia , Lipossomos , Fosfatidilserinas , Sertralina/administração & dosagem , Animais , Antiprotozoários/química , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Feminino , Imunomodulação/efeitos dos fármacos , Leishmania donovani/imunologia , Leishmaniose Visceral/imunologia , Lipossomos/química , Fígado/metabolismo , Fígado/parasitologia , Fígado/patologia , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/metabolismo , Macrófagos/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Fosfatidilserinas/administração & dosagem , Sertralina/química , Baço/metabolismo , Baço/parasitologia , Baço/patologia
19.
Front Immunol ; 10: 2360, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31649671

RESUMO

Altered sialylation is generally maintained by a fine balance between sialidases and sialyltransferases, which plays an essential role during disease pathogenesis. TLR4 is a membrane-bound highly sialylated glycoprotein predominantly having α2,3-linked sialic acids. It is one of the most important client molecules in the anti-leishmanial innate immune arm. Here, we initiated a comprehensive study on the modulation of TLR4 sialylation in Leishmania donovani (L. d)-infected macrophages by a mammalian sialidase/neuraminidase-1 (Neu1) having substrate specificity toward α2,3-linked sialic acids. We observed reduced membrane-associated Neu1 with its decreased enzyme activity in infected macrophages. Moreover, we demonstrated reduced association of Neu1 with TLR4 leading to enhanced sialylation of TLR4 in these infected cells. Conversely, Neu1 over expression exhibited enhanced association of TLR4 with Neu1 leading to reduced sialylation which possibly linked to increased association of TLR4 with its downstream adaptor protein, MyD88. This, in turn, activated downstream MAP kinase signaling pathway, with enhanced nuclear translocation of NFκB that resulted in increased genetic and protein levels expression of Th1 cytokines and effector molecule nitric oxide secretion which ultimately leads to reduced parasite burden in macrophages. This was further validated by Neu1 silencing in infected macrophages which reversed such a situation. Such events strongly confirm the importance of Neu1 in modulation of TLR4 sialylation during parasite infection resulting in impairment of innate immune response. Furthermore, decreased membrane-bound Neu1 in infected macrophages could be attributed to its reduced tyrosine-phosphorylation as well as diminished association with cathepsin A. Both these phenomenon possibly play significant roles in inhibiting translocation of the sialidase from cytosol to membrane. Taken together, our study first time demonstrated impaired translocation of cytosolic Neu1 to the membrane of L. donovani-infected macrophages due to impaired phosphorylation of this enzyme. This novel finding establishes a link between enhanced α2,3-linked sialic acids on TLR4 and reduced membrane-bound Neu1 which plays a significant role for inhibiting downstream signaling to establish successful infection in the host cells.


Assuntos
Leishmania donovani/imunologia , Leishmaniose Visceral , Sistema de Sinalização das MAP Quinases/imunologia , Macrófagos , Neuraminidase/imunologia , Receptor 4 Toll-Like/imunologia , Animais , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/patologia , Macrófagos/imunologia , Macrófagos/parasitologia , Macrófagos/patologia , Mesocricetus , Camundongos , Camundongos Endogâmicos BALB C , Ácidos Siálicos/imunologia
20.
J Appl Lab Med ; 4(3): 404-409, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31659077

RESUMO

BACKGROUND: Hypergammaglobulinemia is present in visceral leishmaniasis (VL), inducing the formation of immune complexes (ICs), which interferes in conventional serology. Parasitic haptens block antibodies, making it difficult to identify and detect them. ICs could be determined indirectly by acid dissociative ELISA (DE) seroconversion in natural and experimental VL. METHODS: We determined the frequency of samples that seroconverted in DE or presented a 10% increase in DE (ΔDE) in 3 types of VLs-hamster, canine, and human samples-with larger antigen determination by direct antigen capture in experimental samples. RESULTS: The ΔDE frequency is increased in all VL models: human (34%), canine (27%), and hamster (25%) samples. Seroconversion was present in hamster (14%), dog (1%), and human (6%) samples. During experimental infection, higher frequencies (28%) of circulating antigens were observed at the 30th day, associated with higher ΔDE (47%) and seroconversion (22%), with lower frequencies in other periods. CONCLUSIONS: The frequency of ΔED and seroconversion samples found in natural and experimental infection suggests that specific antibodies can be blocked by low molecular weight antigens that interfere qualitatively (seroconversion) or quantitatively (ΔDE) in serology. Several antigen types may be involved, as high molecular weight proteins and low molecular weight glycoconjugates. The higher frequency of those indirect demonstrations of antibody-blocking antigen or haptens that could be acid-removed in VL has implications for the development of assays for detection of circulating or antibody-bound 1- to 3-kDa antigens, which could interfere in diagnosis and also in the immune response of the host.


Assuntos
Complexo Antígeno-Anticorpo/imunologia , Antígenos de Protozoários/imunologia , Doenças do Cão/diagnóstico , Haptenos/imunologia , Leishmania donovani/imunologia , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/imunologia , Animais , Anticorpos Antiprotozoários/sangue , Anticorpos Antiprotozoários/imunologia , Complexo Antígeno-Anticorpo/sangue , Antígenos de Protozoários/sangue , Cricetinae , Doenças do Cão/sangue , Doenças do Cão/imunologia , Doenças do Cão/parasitologia , Cães , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Testes Imunológicos , Leishmaniose Visceral/sangue , Leishmaniose Visceral/parasitologia , Soroconversão
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