Publications by authors named "Washington L C dos-Santos"

35 Publications

Hematological Changes in Dogs with Visceral Leishmaniasis Are Associated with Increased IFN-γ and TNF Gene Expression Levels in the Bone Marrow.

Microorganisms 2021 Jul 29;9(8). Epub 2021 Jul 29.

Fundação Oswaldo Cruz, Centro de Pesquisas Gonçalo Moniz, Salvador 40296-710, BA, Brazil.

Visceral leishmaniasis is associated with a variety of hematological abnormalities. In this study, we correlated the hematological changes in the peripheral blood of dogs naturally infected with with the distribution of cell lineages and cytokine gene expression patterns in the bone marrow. Samples from 63 naturally semidomiciled dogs living in an endemic area of visceral leishmaniasis were analyzed. infection was detected in 50 dogs (79.3%). Among those, 18 (32%) had positive splenic cultures and showed more clinical signs. They also had lower red blood cell counts and leukocytosis with an increased number of neutrophils and monocytes in peripheral blood compared to dogs negative to this test. DNA was detected in the bone marrow of 8/14 dogs with positive splenic culture. Dogs with infection in the bone marrow presented with histiocytosis ( = 0.0046), fewer erythroid cell clusters ( = 0.0127) and increased gene expression levels of IFN-γ ( = 0.0015) and TNF ( = 0.0091). The data shown herein suggest that inflammatory and cytokine gene expression changes in bone marrow may contribute to the peripheral blood hematological changes observed in visceral leishmaniasis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/microorganisms9081618DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8398899PMC
July 2021

Urinary cytology: a potential tool for differential diagnosis of acute kidney injury in patients with nephrotic syndrome.

BMC Res Notes 2020 Aug 27;13(1):401. Epub 2020 Aug 27.

Fundação Oswaldo Cruz, Instituto Gonçalo Moniz, Rua Waldemar Falcão 121, Candeal, Salvador, BA, CEP 40296-710, Brazil.

Objective: Acute tubular necrosis (ATN) is a frequent cause of acute kidney injury (AKI). In patients with nephrotic syndrome (NS), AKI demands the differential diagnosis between ATN and rapidly progressive glomerulonephritis. In some cases, conclusive diagnosis is possible only by kidney biopsy. We aimed to study the potential use of urine cytology in the differential diagnosis between ATN and proliferative glomerular lesion in patients with NS.

Results: Cell size analysis showed a higher proportion of small cells and a lower proportion of large cells in the urine of patients with AKI. Cells phenotypes were easily defined using cytological preparations. Leukocytes were found to be a primary classifier of NS groups, with higher number in patients with AKI and patients with proliferative glomerular lesions. Although renal biopsy is still required for confirmative diagnosis, our data suggests that urinary cytology can be readily performed and support the differential diagnosis between proliferative glomerular lesion and ATN in patients with NS and AKI.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13104-020-05244-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7453712PMC
August 2020

Phenotypical Characterization of Spleen Remodeling in Murine Experimental Visceral Leishmaniasis.

Front Immunol 2020 15;11:653. Epub 2020 Apr 15.

Laboratório de Patologia Estrutural e Molecular, Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Brazil.

Visceral leishmaniasis (VL) is caused by or infection. One of the main problems related to this disease is the emergence of severe clinical forms with a lethality of 5-20%, even while under specific treatment. In humans and other species susceptible to fatal VL, such as dogs and hamsters, the disruption of splenic white pulp (WP) is accompanied by disease progression. Control of VL progression is seen in BALB/c mice, as evidenced by a mild clinical presentation and controlled parasite replication in the liver and spleen. In this study, we investigated the features involved in the morphological remodeling of splenic compartments associated with the control of VL progression to death. We evaluated cohorts of BALB/c mice after 30, 60, and 90 days of infection by . Spleen morphology, cell population subsets and cytokine production were studied in the spleen using flow- and histo-cytometry. Intraperitoneal infection with 10 promastigotes of led to progressive increases in spleen size at 60 and 90 days after infection. Splenomegaly was the only clinical sign of disease observed. At 30 days after infection, hyperplasia in the WP and decreased numbers of plasmacytoid dendritic cells were observed. The WP hyperplasia subsided at 60 days post-infection. However, the splenomegaly remained in association with increased numbers of macrophages, B and T lymphocytes and plasma cells. An increased number of lymphoid tissue inducer (LTi) cells was observed; these were distributed around the periarteriolar lymphoid sheath in control mice and scattered throughout the red pulp in the -infected mice. After 90 days of infection, increased IL-6 and IFN-γ production was seen in the spleen, as well as higher frequencies of follicular and plasmacytoid dendritic cells. The data presented herein emphasizes the potential role of spleen remodeling in the control of severe forms of VL and highlights features potentially involved in this process.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fimmu.2020.00653DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7174685PMC
April 2021

Classification of glomerular hypercellularity using convolutional features and support vector machine.

Artif Intell Med 2020 03 25;103:101808. Epub 2020 Jan 25.

IVISION Lab, Universidade Federal da Bahia, Bahia, Brazil. Electronic address:

Glomeruli are histological structures of the kidney cortex formed by interwoven blood capillaries, and are responsible for blood filtration. Glomerular lesions impair kidney filtration capability, leading to protein loss and metabolic waste retention. An example of lesion is the glomerular hypercellularity, which is characterized by an increase in the number of cell nuclei in different areas of the glomeruli. Glomerular hypercellularity is a frequent lesion present in different kidney diseases. Automatic detection of glomerular hypercellularity would accelerate the screening of scanned histological slides for the lesion, enhancing clinical diagnosis. Having this in mind, we propose a new approach for classification of hypercellularity in human kidney images. Our proposed method introduces a novel architecture of a convolutional neural network (CNN) along with a support vector machine, achieving near perfect average results on FIOCRUZ data set in a binary classification (lesion or normal). Additionally, classification of hypercellularity sub-lesions was also evaluated, considering mesangial, endocapilar and both lesions, reaching an average accuracy of 82%. Either in binary task or in the multi-classification one, our proposed method outperformed Xception, ResNet50 and InceptionV3 networks, as well as a traditional handcrafted-based method. To the best of our knowledge, this is the first study on deep learning over a data set of glomerular hypercellularity images of human kidney.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.artmed.2020.101808DOI Listing
March 2020

Assessment of histological liver alterations in dogs naturally infected with Leishmania infantum.

Parasit Vectors 2019 Oct 16;12(1):487. Epub 2019 Oct 16.

Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, BA, Brazil.

Background: The liver plays a central role in the development of canine visceral leishmaniasis. Studies of natural infection in animals and humans indicate a direct relationship between resolution of infection and the formation and maturation of granulomas in the liver. However, in contrast to other reports in the literature, the present study found no differences in the characteristics of hepatic granulomas that could be related to resistance or susceptibility to Leishmania. Here, we describe the hepatic alterations observed in dogs with differing clinical manifestations of visceral leishmaniasis in an endemic area in the state of Bahia, Brazil.

Methods: We examined 148 animals in an endemic area. The animals were clinically examined, and the infection was determined by ELISA, spleen aspirate culture and quantitative PCR. The animals were grouped into asymptomatic or symptomatic based on the number of signs of LV. The histological liver evaluation was performed in a blinded way.

Results: Our results indicated no association between the characteristics of granulomas and clinical presentation. We found an association between the intensity of this inflammatory response and parasite load in the animals' spleens. It is important to note that while hepatic alterations, such as portal and perivascular inflammation and the presence of larger amounts of granulomas, were linked with higher parasite loads, we found the inverse to be true with respect to intrasinusoidal lymphocytosis, the formation of intrasinusoidal inflammatory cell aggregates and Kupffer cell hypertrophy.

Conclusions: Our findings suggest that the presence of mononuclear inflammatory cells inside the sinusoids is more important than that of organized granulomas in terms of the containment of parasitism by the host. We suggest that the presence of granulomas indicates the failure of a first line of defense mechanism in the control of parasite infection, which could be related to the presence of inflammatory cells and Kupffer cell hypertrophy inside the sinusoids. We further demonstrated that dogs with active Leishmania spp. infection present a higher frequency of inflammatory changes in the liver. In addition to being correlated with the severity of clinical manifestation, these hepatic alterations were also associated with changes in hematological and biochemical parameters.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13071-019-3723-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6796381PMC
October 2019

The sickle cell trait and end stage renal disease in Salvador, Brazil.

PLoS One 2018 17;13(12):e0209036. Epub 2018 Dec 17.

Instituto Gonçalo Moniz-FIOCRUZ-Bahia, Salvador, Brazil.

Background: Carriers of the sickle cell trait (HbAS) usually remain asymptomatic. However, under conditions of low tissue oxygenation, red blood cell sickling and vascular obstruction may develop. Chronic kidney disease (CKD) can arise from conditions promoting low-oxygen in kidney tissue, which may be aggravated by the presence of the sickle cell trait. In addition, CKD can arise from other genetic traits.

Aim: To compare the frequency of HbAS among hemodialysis patients and the general newborn population of Salvador (Bahia-Brazil), as well as to investigate the frequencies of apolipoprotein L1 risk variants in patients undergoing hemodialysis.

Methods: A cross-sectional study included 306 patients with ESRD (End Stage Renal Disease) on hemodialysis for no more than three years. Hemoglobin profiles were characterized by high-performance liquid chromatography. To estimate the sickle cell trait frequency in the general population of Salvador, we analyzed data collected by a local neonatal screening program between 2011 and 2016. To exclude the potential contributing effect of the apolipoprotein L1 (APOL1) gene variants, we performed genotyping by PCR and DNA sequencing of 45 patients.

Results: The frequency of HbAS was significantly higher in hemodialysis patients (9.8%) than in the general population (4.6%): Odds Ratio = 2.32 (95% CI = 1.59-3.38). No differences in demographic, clinical or laboratory data were found among patients with or without the sickle cell trait. The frequency of patients with none, one or two APOL1 risk haplotypes (G1 and G2) for CKD were 80%, 18% and 2%, respectively.

Conclusions: The frequency of the sickle cell trait is higher in patients with ESRD on hemodialysis compared to the general population. APOL1 haplotypes do not seem to be the determinant of ESRD in these patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0209036PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6296547PMC
May 2019

Histological Disorganization of Spleen Compartments and Severe Visceral Leishmaniasis.

Front Cell Infect Microbiol 2018 13;8:394. Epub 2018 Nov 13.

Fundação Oswaldo Cruz, Instituto Gonçalo Moniz, Salvador, Brazil.

The spleen is a secondary lymphoid organ responsible for immune surveillance against blood-circulating pathogens. Absence of the spleen is associated with increased susceptibility to systemic spread and fatal infection by different pathogens. Severe forms of visceral leishmaniasis are associated with disorganization of spleen compartments where cell interactions essential for splenic immunological function take place. White pulp atrophies, secondary lymphoid follicles and marginal zones vanish, and the boundaries separating white and red pulp blur. Leukocyte populations are reduced or disappear or are replaced by plasma cells. In this paper, we review the published data on spleen disorganization in severe forms of visceral leishmaniasis and propose a histological classification to help the exchange of information among research groups.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fcimb.2018.00394DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6243053PMC
September 2019

Parasitic load and histological aspects in different regions of the spleen of dogs with visceral leishmaniasis.

Comp Immunol Microbiol Infect Dis 2018 Feb 27;56:14-19. Epub 2017 Nov 27.

Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, (IGM-FIOCRUZ/BA), Salvador, Bahia, Brazil; Instituto Nacional de Ciência e Tecnologia de Doenças Tropicais (INCT-DT), Brazil. Electronic address:

Leishmania infantum causes from subclinical infection to severe disease in humans and dogs. The spleen is one of the organs most affected by the infection. Although evidence exists that the parasitic load distribution and histological alterations may not be homogeneous in the affected organs of naturally infected individuals, it has not been formally demonstrated using the current techniques used for studying the disease. In six dogs naturally infected with Leishmania, parasitic load and histological changes were compared in samples collected from the lower, middle and upper third of the spleen. Parasitic load in the spleen of the group of dogs was variable, revealing a difference of 61 times between animals with the lowest and the highest parasitism. The set of parasitic load values of each dog showed a cluster trend, when compared to the other animals. Nevertheless, the parasitic load values of each dog showed a variation ranging from 3.2 to 34.7 times between lowest and highest value. Histological changes showed recognizable variation in frequency (granulomas) or intensity (perisplenitis) in the spleen of 2 out of the 6 dogs. The agreement of histological findings between samples collected from the different thirds of the spleen was good (kappa coeficient, 0.61-0.80) very good (0.81-0.99) or perfect (1.00), for most of the parameters analyzed. Variability of parasitic load and, to a lesser extent, histological changes in spleen of dogs with visceral leishmaniasis is observed. Such variability may be taken in account in the design of studies on pathogenesis, vaccine and therapeutic drug development.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cimid.2017.11.003DOI Listing
February 2018

Sera from Visceral Leishmaniasis Patients Display Oxidative Activity and Affect the TNF- Production by Macrophages .

Biomed Res Int 2017 5;2017:5861453. Epub 2017 Nov 5.

Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal da Bahia, Salvador, BA, Brazil.

Mammalian protection against leishmanial infection depends on the development of an effective immune response. Zoonotic visceral leishmaniasis (ZVL) patients are usually unable to mount an effective immune response against the parasite and indeed appear to be severely immunosuppressed. This suppression has strong nonspecific and specific components mediated by serum factors and leishmanicidal activity of infected macrophages, respectively. The lipid profile has been shown to be altered in ZVL patients' sera. This work aimed at (i) determining the HDL, Apo A1, LDL, and VLDL concentrations in ZVL patients' sera; (ii) investigating the oxidative effect of ZVL patients' sera on the -carotene matrix; (iii) measuring IL-10, IL-6, IL-12p40, and tumour necrosis factor- (TNF-) concentrations in the macrophage cultures, to which 10% of ZVL patients' serum had been added. Levels of HDL, LDL fraction, and apolipoprotein A1 in ZVL patients' sera were lower than those of healthy individuals' sera, except for the mean level of VLDL. The matrix of -carotene and linoleic acid system was oxidized in the presence of ZLV patients' sera. The presence of ZVL patients' sera did not modify the cytokine production of IL-6, IL-12p40, and IL-10 by human macrophages but TNF- production was altered, probably due to lack of macrophage stimulation by lipoprotein.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2017/5861453DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5694613PMC
July 2018

Selecting the right gate to identify relevant cells for your assay: a study of thioglycollate-elicited peritoneal exudate cells in mice.

BMC Res Notes 2017 Dec 6;10(1):695. Epub 2017 Dec 6.

Laboratório de Patologia e Biointervenção, Fundação Oswaldo Cruz, FIOCRUZ-BA, Instituto Gonçalo Moniz, Rua Waldemar Falcão, nº 121, Candeal, Salvador, Bahia, CEP 40296-710, Brazil.

Objective: In this study, we investigate the diversity and modulation of leukocyte populations represented in the gates defined by size and granularity at different time points of thioglycollate-induced peritonitis in mouse.

Results: The inflammatory cells were distributed into four regions (R1-R4) of a data plot graph defined by cell size and granularity. R1 and R2 contained agranular cells that were small in size and predominately included T (CD3) lymphocytes along with B (B220) lymphocytes. Macrophages (F4/80) were the predominant cells found in the R3 region. However, these cells were present in all regions, albeit at a lower frequency in R1 and R2. Granulocytes (Gr1) were mainly distributed in R3 and R4. The wide distribution of F4/80 and Gr1 cells may reflect the recruitment and activation state of the different macrophage and granulocyte populations. Based on these observations, size and granularity may contribute to an initial step in the analysis and sorting of thioglycollate-elicited peritoneal exudate cells. However, the developmental stage and cell activation state may interfere with cell segregation using size and granularity as parameters.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13104-017-3019-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5718147PMC
December 2017

Evaluation of a new set of recombinant antigens for the serological diagnosis of human and canine visceral leishmaniasis.

PLoS One 2017 28;12(9):e0184867. Epub 2017 Sep 28.

Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz (Fiocruz-Pernambuco), Recife, Pernambuco, Brazil.

Current strategies for the control of zoonotic visceral leishmaniasis (VL) rely on its efficient diagnosis in both human and canine hosts. The most promising and cost effective approach is based on serologic assays with recombinant proteins. However, no single antigen has been found so far which can be effectively used to detect the disease in both dogs and humans. In previous works, we identified Leishmania infantum antigens with potential for the serodiagnosis of VL. Here, we aimed to expand the panel of the available antigens for VL diagnosis through another screening of a genomic expression library. Seven different protein-coding gene fragments were identified, five of which encoding proteins which have not been previously studied in Leishmania and rich in repetitive motifs. Poly-histidine tagged polypeptides were generated from six genes and evaluated for their potential for diagnosis of VL by ELISA (Enzyme Linked ImmunoSorbent Assay) with sera from infected humans and dogs. None of those was valid for the detection of human VL (26-52% sensitivity) although their performance was increased in the canine sera (48-91% sensitivity), with one polypeptide useful for the diagnosis of canine leishmaniasis. Next, we assayed a mixture of three antigens, found to be best for human or canine VL, among 13 identified through different screenings. This "Mix" resulted in similar levels of sensitivity for both human (84%) and canine (88%) sera. With improvements, this validates the use of multiple proteins, including antigens identified here, as components of a single system for the diagnosis of both forms of leishmaniasis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0184867PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5619722PMC
October 2017

PathoSpotter-K: A computational tool for the automatic identification of glomerular lesions in histological images of kidneys.

Sci Rep 2017 04 24;7:46769. Epub 2017 Apr 24.

Fundacao Oswaldo Cruz (FIOCRUZ) - Instituto Gonçalo Moniz, Salvador, Bahia, Brazil.

PathoSpotter is a computational system designed to assist pathologists in teaching about and researching kidney diseases. PathoSpotter-K is the version that was developed to detect nephrological lesions in digital images of kidneys. Here, we present the results obtained using the first version of PathoSpotter-K, which uses classical image processing and pattern recognition methods to detect proliferative glomerular lesions with an accuracy of 88.3 ± 3.6%. Such performance is only achieved by similar systems if they use images of cell in contexts that are much less complex than the glomerular structure. The results indicate that the approach can be applied to the development of systems designed to train pathology students and to assist pathologists in determining large-scale clinicopathological correlations in morphological research.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/srep46769DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5402276PMC
April 2017

A minimally invasive approach to spleen histopathology in dogs: A new method for follow-up studies of spleen changes in the course of Leishmania infantum infection.

Comp Immunol Microbiol Infect Dis 2016 Oct 30;48:87-92. Epub 2016 Aug 30.

Fundação Oswaldo Cruz, Centro de Pesquisas Gonçalo Moniz, Salvador, BA, Brazil;, Brazil. Electronic address:

Severe forms of zoonotic visceral leishmaniosis (ZVL) are associated with disruption of the spleen structure. However, the study of spleen histology requires splenectomy or necropsy. In this work, we present a minimally invasive cell-block technique for studying spleen tissue histology in dogs with ZVL. We examined 13 dogs with and seven dogs without Leishmania infantum infection. The dogs with Leishmania infection had a lower frequency of lymphoid follicles (2/13, Fisher's test, P<0.02) and a higher density of plasma cells (score 3, Fisher's test, P<0.02) than uninfected dogs (5/7 exhibiting lymphoid follicles and a plasma cell score of 1). The dogs with Leishmania infection also presented with granulomas (8/13) and infected macrophages (5/13). These differences in the histological presentations of spleen tissue from infected and uninfected dogs corresponded to changes observed in conventional histology. Hence, the cell-block technique described here may be used in the follow-up care and study of dogs with ZVL and other diseases in both clinical practice and research.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cimid.2016.08.007DOI Listing
October 2016

Disruption of Splenic Lymphoid Tissue and Plasmacytosis in Canine Visceral Leishmaniasis: Changes in Homing and Survival of Plasma Cells.

PLoS One 2016 31;11(5):e0156733. Epub 2016 May 31.

Fundação Oswaldo Cruz - BA, Centro de Pesquisas Gonçalo Moniz, Salvador, BA, Brazil.

Visceral leishmaniasis (VL) is a disease caused by Leishmania infantum, which is transmitted by phlebotomine sandflies. Dogs are the main urban reservoir of this parasite and the disease presents similar characteristics in both humans and dogs. In this paper, we investigated the potential pathways involved in plasma cell replacement of normal cell populations in the spleen, with respect to disease severity in dogs from an endemic area for visceral leishmaniasis. To this end, canine spleen samples were grouped into three categories: TYPE1SC- (non-infected dogs or without active infection with organized white pulp), TYPE1SC+ (infected dogs with organized white pulp) or TYPE3SC+ (infected animals with disorganized white pulp). We analyzed the distribution of different plasma cell isotypes (IgA, IgG and IgM) in the spleen. The expression of cytokines and chemokines involved in plasma cell homing and survival were assessed by real time RT-PCR. Polyclonal B cell activation and hypergammaglobulinemia were also evaluated. The proportion of animals with moderate or intense plasmacytosis was higher in the TYPE3SC+ group than in the other groups (Fisher test, P<0.05). This was mainly due to a higher density of IgG+ plasma cells in the red pulp of this group. The albumin/globulin ratio was lower in the TYPE3SC+ animals than in the TYPE1SC- or TYPE1SC+ animals, which evidences VL-associated dysproteinemia. Interestingly, TYPE3SC+ animals showed increased expression of the BAFF and APRIL cytokines, as well as chemokine CXCL12. Aberrant expression of BAFF, APRIL and CXCL12, together with amplified extrafollicular B cell activation, lead to plasma cell homing and the extended survival of these cells in the splenic red pulp compartment. These changes in the distribution of immunocompetent cells in the spleen may contribute to the progression of VL, and impair the spleen's ability to protect against blood borne pathogens.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0156733PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4887081PMC
July 2017

Leishmania infection modulates beta-1 integrin activation and alters the kinetics of monocyte spreading over fibronectin.

Sci Rep 2015 Aug 7;5:12862. Epub 2015 Aug 7.

Fundação Oswaldo Cruz-Bahia, Centro de Pesquisas Gonçalo Moniz, Brazilian Ministry of Health, Salvador, Brazil.

Contact with Leishmania leads to a decreases in mononuclear phagocyte adherence to connective tissue. In this work, we studied the early stages of bond formation between VLA4 and fibronectin, measured the kinetics of membrane alignment and the monocyte cytoplasm spreading area over a fibronectin-coated surface, and studied the expression of high affinity integrin epitope in uninfected and Leishmania-infected human monocytes. Our results show that the initial VLA4-mediated interaction of Leishmania-infected monocyte with a fibronectin-coated surface is preserved, however, the later stage, leukocyte spreading over the substrate is abrogated in Leishmania-infected cells. The median of spreading area was 72 [55-89] μm(2) for uninfected and 41 [34-51] μm(2) for Leishmania-infected monocyte. This cytoplasm spread was inhibited using an anti-VLA4 blocking antibody. After the initial contact with the fibronectrin-coated surface, uninfected monocyte quickly spread the cytoplasm at a 15 μm(2) s(-1) ratio whilst Leishmania-infected monocytes only made small contacts at a 5.5 μm(2) s(-1) ratio. The expression of high affinity epitope by VLA4 (from 39 ± 21% to 14 ± 3%); and LFA1 (from 37 ± 32% to 18 ± 16%) molecules was reduced in Leishmania-infected monocytes. These changes in phagocyte function may be important for parasite dissemination and distribution of lesions in leishmaniasis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/srep12862DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4528201PMC
August 2015

A case of conventional treatment failure in visceral leishmaniasis: leukocyte distribution and cytokine expression in splenic compartments.

BMC Infect Dis 2014 Sep 9;14:491. Epub 2014 Sep 9.

Fundação Oswaldo Cruz, Centro de Pesquisas Gonçalo Moniz, Salvador, BA, Brazil.

Background: In this paper we study the distribution of leukocyte populations and of cytokine-producing cells in the spleen of a patient with visceral leishmaniasis resistant to clinical treatment. It is the first attempt to compare the distribution of leukocyte populations and cytokine-producing cells in the splenic compartments of a patient with visceral leishmaniasis with those observed in patients without the disease.

Case Presentation: A 25-year-old male, farmer, was hospitalized on several occasions with diagnosis of visceral leishmaniasis and received all recommended treatments for the disease with only transient improvement followed by relapse. He was eventually subjected to splenectomy in order to control the effects of hypersplenism and to potentially overcome infection. After surgery and combined chemotherapy, the disease evolved to cure. In comparison with the spleens of the other two patients without visceral leishmaniasis, an increase was observed in the CD4/CD8 ratio and in the number of IL-10- and FoxP3-producing cells, while the number of IL-17-producing cells was lower in the spleen of the patient with visceral leishmaniasis.

Conclusion: This report confirms previous data on changes in the CD4/CD8 ratio in the spleens of patients with visceral leishmaniasis. Additionally the data presented herein suggests that splenic FoxP3- and IL-17-producing cells are involved in the chronicity of visceral leishmaniasis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1471-2334-14-491DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4175220PMC
September 2014

Leishmania amazonensis infection impairs dendritic cell migration from the inflammatory site to the draining lymph node.

BMC Infect Dis 2014 Aug 20;14:450. Epub 2014 Aug 20.

Centro de Pesquisas Gonçalo Moniz, Oswaldo Cruz Foundation, Fiocruz, LPBI, Salvador, Brazil.

Background: In vitro studies show that Leishmania infection decreases the adhesion of inflammatory phagocytes to connective tissue by a mechanism dependent on the modulation of integrin function. However, we know little about the influence of this reduction in leukocyte adhesion on parasite dissemination from the infection site.

Methods: In this work, we used a model of chronic peritonitis induced by thioglycollate to study the effect of L. amazonensis infection on the ability of inflammatory phagocyte populations to migrate from an inflammatory site to the draining lymph node. Uninfected or Leishmania-infected thioglycollate-elicited peritoneal exudate cells were transferred from C57BL/6 to BALB/c mice or from Ly5.1+ to Ly5.1- mice. The transferred cells were injected into the peritoneal cavity and tracked to the draining lymph node.

Results: Migrating cells corresponded to approximately 1% of the injected leukocytes. The proportion of migrating CD11b+CD11c+ (myeloid dendritic cell) was lower after incubation with Leishmania (1.3 to 2.6 times lower in the experiments using C57BL/6 to BALB/c animals and 2.7 to 3.4 times lower in the experiments using Ly5.1+ to Ly5.1- animals) than after leukocyte incubation with medium alone (P < 0.01). There was no consistent decrease in the migration of CD11b+F4/80+ (macrophage) or SSChi GR-1+ (neutrophil) populations.

Conclusions: Coincubation with Leishmania changes the migratory pattern of dendritic cells in vivo. Such changes in dendritic cell migration may be associated with immunological events that maintain inflammation at the sites of infection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1471-2334-14-450DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4143564PMC
August 2014

Arginase I, polyamine, and prostaglandin E2 pathways suppress the inflammatory response and contribute to diffuse cutaneous leishmaniasis.

J Infect Dis 2015 Feb 14;211(3):426-35. Epub 2014 Aug 14.

Centro de Pesquisas Gonçalo Moniz/FIOCRUZ-BA Faculdade de Medicina, Universidade Federal da Bahia, Salvador Instituto Nacional de Ciência e Tecnologia de Investigação em Imunologia, São Paulo, Brazil.

Diffuse cutaneous leishmaniasis (DCL) is a rare clinical manifestation of tegumentary leishmaniasis. The molecular mechanisms underlying DCL pathogenesis remain unclear, and there is no efficient treatment available. This study investigated the systemic and in situ expression of the inflammatory response that might contribute to suppression in DCL. The plasma levels of arginase I, ornithine decarboxylase (ODC), transforming growth factor β (TGF-β), and prostaglandin E2 (PGE2) were higher in patients with DCL, compared with patients with localized cutaneous leishmaniasis (LCL) or with controls from an area of endemicity. In situ transcriptomic analyses reinforced the association between arginase I expression and enzymes involved in prostaglandin and polyamine synthesis. Immunohistochemistry confirmed that arginase I, ODC, and cyclooxygenase2 expression was higher in lesion biopsy specimens from patients with DCL than in those from patients with LCL. Inhibition of arginase I or ODC abrogates L. amazonensis replication in infected human macrophages. Our data implicate arginase I, ODC, PGE2, and TGF-β in the failure to mount an efficient immune response and suggest perspectives in the development of new strategies for therapeutic intervention for patients with DCL.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/infdis/jiu455DOI Listing
February 2015

Severe clinical presentation of visceral leishmaniasis in naturally infected dogs with disruption of the splenic white pulp.

PLoS One 2014 3;9(2):e87742. Epub 2014 Feb 3.

Fundação Oswaldo Cruz, Centro de Pesquisas Gonçalo Moniz, Salvador, Bahia, Brazil.

In this work, we investigated the association between the disruption of splenic lymphoid tissue and the severity of visceral leishmaniasis in dogs. Clinical and laboratory data from 206 dogs were reviewed. Spleen sections collected during the euthanasia of these animals were analyzed, and the splenic lymphoid tissue samples were classified as well organized (spleen type 1), slightly disorganized (spleen type 2), or moderately to extensively disorganized (spleen type 3). Of 199 dogs with evidence of Leishmania infection, 54 (27%) had spleen type 1, 99 (50%) had spleen type 2, and 46 (23%) had spleen type 3. The number of clinical signs associated with visceral leishmaniasis was significantly higher in the animals with evidence of Leishmania infection and spleen type 2 or 3 than in the animals with spleen type 1. Alopecia, anemia, dehydration, dermatitis, lymphadenopathy, and onychogryphosis were all more frequent among animals with evidence of Leishmania infection and spleen type 3 than among the dogs with evidence of Leishmania infection and spleen type 1. The association between the severity of canine visceral leishmaniasis and the disorganization of the splenic lymphoid tissue was even more evident in the group of animals with positive spleen culture. Conjunctivitis and ulceration were also more common in the animals with spleen type 3 than in the animals with spleen type 1. The serum levels (median, interquartile range) of albumin (1.8, 1.4-2.3 g/dL) and creatinine (0.7, 0.4-0.8 mg/dL) were significantly lower and the serum levels of aspartate aminotransferase were significantly higher (57, 39-95 U) in animals with spleen type 3 than in animals with spleen type 1 (2.8, 2.4-3.4 g/dL; 0.9, 0.7-1.2 mg/dL and 23, 20-32 U, respectively). Our data confirm the hypothesis that disruption of the splenic lymphoid tissue is associated with a more severe clinical presentation of canine visceral leishmaniasis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0087742PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3911999PMC
October 2014

Temporal distribution of positive results of tests for detecting Leishmania infection in stray dogs of an endemic area of visceral leishmaniasis in the Brazilian tropics: a 13 years survey and association with human disease.

Vet Parasitol 2012 Dec 26;190(3-4):591-4. Epub 2012 Jun 26.

Fundação Oswaldo Cruz (Fiocruz), Centro de Pesquisas Gonçalo Moniz, Rua Waldemar Falcão 121, Candeal, Salvador 40-296-710, BA, Brazil.

Human visceral leishmaniasis occurs in periodic waves in endemic areas of Brazil. In this study we followed the prevalence of human visceral leishmaniasis and of Leishmania infantum infection in stray dogs of an endemic area of visceral leishmaniasis at periods of time between 1997 and 2010. Prevalence of human visceral leishmaniasis had two peaks (40 cases) in 1997 and 2006 with sharp declines to 2 cases in 2001 and to 5 cases in 2008. Similar fluctuations were also observed in the occurrence of positive spleen culture and anti-Leishmania serology in dogs, although the proportion of dogs with active spleen parasitism remained relatively high even in the periods of low prevalence of human disease. These observations support the notion that stray dogs may constitute a renewable source of parasites, capable of sustaining the persistence of the infection in urban areas, even in periods of low transmission by phlebotomines.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.vetpar.2012.06.025DOI Listing
December 2012

Low CXCL13 expression, splenic lymphoid tissue atrophy and germinal center disruption in severe canine visceral leishmaniasis.

PLoS One 2012 5;7(1):e29103. Epub 2012 Jan 5.

Fundação Oswaldo Cruz-Centro de Pesquisas Gonçalo Moniz, Salvador, Bahia, Brazil.

Visceral leishmaniasis is associated with atrophy and histological disorganization of splenic compartments. In this paper, we compared organized and disorganized splenic lymphoid tissue from dogs naturally infected with Leishmania infantum assessing the size of the white pulp compartments, the distribution of T, B and S100+ dendritic cells, using immunohistochemistry and morphometry and the expression of CCR7 and the cytokines, CXCL13, lymphotoxin (LT)-α, LT-β, CCL19, CCL21, TNF-α, IL-10, IFN-γ and TGF-β, using by real time RT-PCR. The lymphoid follicles and marginal zones were smaller (3.2 and 1.9 times, respectively; Mann-Whitney, P<0.02) in animals with disorganized splenic tissue in comparison to those with organized splenic lymphoid tissue. In spleens with disorganized lymphoid tissue, the numbers of T cells and S100+ dendritic cells were decreased in the follicles, and the numbers of B cells were reduced in both the follicles and marginal zones. CXCL13 mRNA expression was lower in animals with disorganized lymphoid tissue (0.5±0.4) compared to those with organized lymphoid tissue (2.7±2.9, both relative to 18S expression, P = 0.01). These changes in the spleen were associated with higher frequency of severe disease (7/12) in the animals with disorganized than in animals with organized (2/13, Chi-square, P = 0.01) splenic lymphoid tissue. The data presented herein suggest that natural infection with Leishmania infantum is associated with the impairment of follicular dendritic cells, CXCL13 expression, B cell migration and germinal center formation and associates these changes with severe clinical forms of visceral leishmaniasis. Furthermore the fact that this work uses dogs naturally infected with Leishmania infantum emphasizes the relevance of the data presented herein for the knowledge on the canine and human visceral leishmaniasis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0029103PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3252310PMC
May 2012

Characterization of novel Leishmania infantum recombinant proteins encoded by genes from five families with distinct capacities for serodiagnosis of canine and human visceral leishmaniasis.

Am J Trop Med Hyg 2011 Dec;85(6):1025-34

Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.

To expand the available panel of recombinant proteins that can be useful for identifying Leishmania-infected dogs and for diagnosing human visceral leishmaniasis (VL), we selected recombinant antigens from L. infantum, cDNA, and genomic libraries by using pools of serum samples from infected dogs and humans. The selected DNA fragments encoded homologs of a cytoplasmic heat-shock protein 70, a kinesin, a polyubiquitin, and two novel hypothetical proteins. Histidine-tagged recombinant proteins were produced after subcloning these DNA fragments and evaluated by using an enzyme-linked immunosorbent assays with panels of canine and human serum samples. The enzyme-linked immunosorbent assays with different recombinant proteins had different sensitivities (67.4-93.0% and 36.4-97.2%) and specificities (76.1-100% and 90.4-97.3%) when tested with serum samples from Leishmania-infected dogs and human patients with VL. Overall, no single recombinant antigen was sufficient to serodiagnosis all canine or human VL cases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4269/ajtmh.2011.11-0102DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3225146PMC
December 2011

Enhancement of experimental cutaneous leishmaniasis by Leishmania molecules is dependent on interleukin-4, serine protease/esterase activity, and parasite and host genetic backgrounds.

Infect Immun 2011 Mar 20;79(3):1236-43. Epub 2010 Dec 20.

Centro de Pesquisa Gonçalo Moniz, FIOCRUZ, Rua Waldemar Falcão 121, 40296-710 Salvador, Bahia, Brazil.

Most inbred strains of mice, like the BALB/c strain, are susceptible to Leishmania amazonensis infections and resistant to Leishmania braziliensis infections. This parasite-related difference could result from the activity of an L. amazonensis-specific virulence factor. In agreement with this hypothesis, it is shown here that the intravenous injection of BALB/c mice with L. amazonensis amastigote extract (LaE) but not the L. braziliensis extract confers susceptibility to L. braziliensis infection. This effect was associated with high circulating levels of IgG1 anti-L. amazonensis antibodies and with an increase in interleukin-4 (IL-4) production and a decrease in gamma interferon production by draining lymph node cells. Moreover, the effect was absent in IL-4-knockout mice. The biological activity in the LaE was not mediated by amphiphilic molecules and was inhibited by pretreatment of the extract with irreversible serine protease inhibitors. These findings indicate that the LaE contains a virulence-related factor that (i) enhances the Leishmania infection by promoting Th2-type immune responses, (ii) is not one of the immunomodulatory Leishmania molecules described so far, and (iii) is either a serine protease or has an effect that depends on that protease activity. In addition to being Leishmania species specific, the infection-enhancing activity was also shown to depend on the host genetic makeup, as LaE injections did not affect the susceptibility of C57BL/6 mice to L. braziliensis infection. The identification of Leishmania molecules with infection-enhancing activity could be important for the development of a vaccine, since the up- or downmodulation of the immune response against a virulence factor could well contribute to controlling the infection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/IAI.00309-10DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3067519PMC
March 2011

Human mucosal leishmaniasis: neutrophils infiltrate areas of tissue damage that express high levels of Th17-related cytokines.

Eur J Immunol 2010 Oct;40(10):2830-6

Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Brazil.

Mucosal leishmaniasis (ML) is characterised by severe tissue destruction. Herein, we evaluated the involvement of the IL-17-type response in the inflammatory infiltrate of biopsy specimens from 17 ML patients. IL-17 and IL-17-inducing cytokines (IL-1β, IL-23, IL-6 and TGF-β) were detected by immunohistochemistry in ML patients. IL-17(+) cells exhibited CD4(+), CD8(+) or CD14(+) phenotypes, and numerous IL-17(+) cells co-expressed the CC chemokine receptor 6 (CCR6). Neutrophils, a hallmark of Th17-mediated inflammation, were regularly detected in necrotic and perinecrotic areas and stained positive for neutrophil elastase, myeloperoxidase and MMP-9. Taken together, these observations demonstrate the existence of Th17 cells in ML lesions associated with neutrophils in areas of tissue injury and suggest that IL-17 is involved in ML pathogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/eji.200940115DOI Listing
October 2010

Activity of physalins purified from Physalis angulata in in vitro and in vivo models of cutaneous leishmaniasis.

J Antimicrob Chemother 2009 Jul 19;64(1):84-7. Epub 2009 May 19.

Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, BA, Brazil.

Objectives: We have previously demonstrated the immunomodulatory effects of physalins, secosteroids purified from Physalis angulata. Here we investigate the antileishmanial activity of physalins in vitro and in vivo in a model of cutaneous leishmaniasis.

Methods: The antileishmanial activity of physalins B, D and F was tested in Leishmania-infected macrophage cultures. For the in vivo studies, BALB/c mice were infected with Leishmania amazonensis subcutaneously in the ear pinna and treated with physalin F by topical administration.

Results: Physalins B and F were able to reduce the percentage of Leishmania-infected macrophages and the intracellular parasite number in vitro at concentrations non-cytotoxic to macrophages. More importantly, topical treatment with physalin F significantly reduced the lesion size, the parasite load and histopathological alterations in BALB/c mice infected with L. amazonensis.

Conclusions: Our results demonstrate the potent antileishmanial activity of physalins, especially physalin F, and suggest these molecules as the basis for the development of new therapeutic options for cutaneous leishmaniasis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/jac/dkp170DOI Listing
July 2009

Effect of nicotine treatment and withdrawal on random-pattern skin flaps in rats.

Exp Toxicol Pathol 2008 Sep 8;60(6):449-52. Epub 2008 Aug 8.

Escola Bahiana de Medicina e Saúde Pública, Av. Dom João VI no. 274, Brotas, 40290-000 Salvador, BA, Brazil.

Background: Tobacco use is associated with a high incidence of skin necrosis after surgery. The ideal timing for the cessation of tobacco use before plastic surgery has not, however, been precisely determined. The aim of this work was to define the ideal duration of nicotine withdrawal prior to random-pattern skin flap surgery in rats.

Methods: Groups of 11 animals were subcutaneously injected with saline or nicotine (2mg/kg) twice a day and subjected to random-pattern skin flap surgery according to the following protocol: Group I: continuously injected with saline 4 weeks before and 1 week after the surgery; Group II: injected with nicotine for 4 weeks until the day of the surgery; Group III: injected with nicotine for 4 weeks until one day before the surgery; Group IV: injected with nicotine for 4 weeks until 5 days before the surgery; Group V: injected with nicotine for 4 weeks until 10 days before the surgery; Group VI: continuously injected with nicotine for 4 weeks before and 1 week after the surgery. McFARLANE skin flaps were performed on the dorsal skin, and the rats were sacrificed 1 week after the surgery.

Results: The necrotic area was smaller in group I (8.85cm2) than in group II (12.15cm2), III (12.88cm2) and VI (14.84cm2) (ANOVA p<0.0001). There was no difference between groups I, IV (10.13cm2) and V (9.27cm2).

Conclusions: In conclusion, 5 days before surgery was considered the ideal time for nicotine withdrawal in this experimental model.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.etp.2008.02.004DOI Listing
September 2008

Leishmania infection impairs beta 1-integrin function and chemokine receptor expression in mononuclear phagocytes.

Infect Immun 2006 Jul;74(7):3912-21

LPBI, Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Rua Waldemar Falcão no. 121, Candeal, Salvador, BA 40296-710, Brazil.

Leishmania spp. are intracellular parasites that cause lesions in the skin, mucosa, and viscera. We have previously shown that Leishmania infection reduces mononuclear phagocyte adhesion to inflamed connective tissue. In this study, we examined the role of adhesion molecules and chemokines in this process. Infection rate (r = -0.826, P = 0.003) and parasite burden (r = -0.917, P = 0.028) negatively correlated to mouse phagocyte adhesion. The decrease (58.7 to 75.0% inhibition, P = 0.005) in phagocyte adhesion to connective tissue, induced by Leishmania, occurred as early as 2 h after infection and was maintained for at least 24 h. Interestingly, impairment of cell adhesion was sustained by phagocyte infection, since it was not observed following phagocytosis of killed parasites (cell adhesion varied from 15.2% below to 24.0% above control levels, P > 0.05). In addition, Leishmania infection diminished cell adhesion to fibronectin (54.1 to 96.2%, P < 0.01), collagen (15.7 to 83.7%, P < 0.05), and laminin (59.1 to 82.2%, P < 0.05). The CD11b(hi) subpopulation was highly infected (49.6 to 97.3%). Calcium and Mg(2+) replacement by Mn(2+), a treatment that is known to induce integrins to a high state of affinity for their receptors, reverted the inhibition in adhesion caused by Leishmania. This reversion was completely blocked by anti-VLA4 antibodies. Furthermore, expression of CCR4 and CCR5, two chemokine receptors implicated in cell adhesion, was found to be downregulated 16 h after infection (2.8 to 4.1 times and 1.9 to 2.8 times, respectively). Together, these results suggest that mechanisms regulating integrin function are implicated in the change of macrophage adhesion in leishmaniasis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/IAI.02103-05DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1489695PMC
July 2006

A strategy for identifying serodiagnostically relevant antigens of Leishmania or other pathogens in genetic libraries.

Biologicals 2007 Mar 31;35(1):51-4. Epub 2006 Mar 31.

Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Rua Valdemar Falcão 121, 40295-001, Salvador, Brazil.

Different individuals, when infected with the same parasite, rarely produce antibodies against the same set of antigens. Indeed, unless a particular antigen happens to be recognized by antibodies in all individuals, the use of a single antigen in the serodiagnosis of parasitic diseases leads, invariably, to false-negative results. A straightforward method for pin-pointing, in genetic libraries, the precise antigens that would increase serodiagnostic assay sensitivities is presented. The method is based on the utilization of sera that produced false-negative results against previously available antigens. Employing this false-negative serum-selection methodology for the identification of new Leishmania infantum recombinant antigens (rAgs), the sensitivity of a dipstick assay for anti-Leishmania antibodies in a panel of sera from patients with visceral leishmaniasis was increased from 83.3% to 98.1%, without affecting its specificity, by the inclusion of a fifth and a sixth L. infantum rAg.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.biologicals.2006.01.005DOI Listing
March 2007

Montenegro's skin reactions and antibodies against different Leishmania species in dogs from a visceral leishmaniosis endemic area.

Vet Parasitol 2006 Jun 29;139(1-3):21-8. Epub 2006 Mar 29.

Centro de Pesquisas Gonçalo Moniz-Fiocruz, Fundação Oswaldo Cruz, Rua Waldemar Falcão 121, 40295-001 Salvador (BA), Brazil.

In this study, humoral (circulating anti-Leishmania antibodies) and cellular (Montenegro's skin test) immune responses of dogs from an endemic area of visceral leishmaniosis were tested using Leishmania chagasi, Leishmania amazonensis and Leishmania braziliensis antigens. The antibody response was tested in three animal groups, selected according to their anti-L. chagasi antibody activity, as measured by ELISA in the serum: 19 negative (O.D. below 0.30), seven with undefined (O.D. between 0.40 and 0.70) and 12 positive (O.D. above 1.0) ELISA result. In the group of animals with positive ELISA, the antibody activity against L. chagasi antigens (mean O.D.=1.31) was significantly higher (ANOVA, P<0.01) than against L. amazonensis (mean O.D.=0.88) or L. braziliensis (mean O.D.=0.87) antigens. The Montenegro's skin test results obtained with L. chagasi and L. braziliensis antigens showed a fair agreement (kappa=0.309). The same was observed when antigens from L. braziliensis and L. amazonensis were compared (kappa=0.374), whereas a moderate agreement between the results from tests performed with L. chagasi and L. amazonensis antigens was observed (kappa=0.530). The induration areas obtained with L. braziliensis antigen were smaller than those obtained with the other antigens. The data presented herein indicate that the use of antigens from different Leishmania species may interfere with the results of the immunological tests performed in dogs in an endemic area of visceral leishmaniosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.vetpar.2006.02.033DOI Listing
June 2006

Role of interleukin-4 and prostaglandin E2 in Leishmania amazonensis infection of BALB/c mice.

Microbes Infect 2006 Apr 19;8(5):1219-26. Epub 2006 Jan 19.

Centro de Pesquisas Gonçalo Moniz, FIOCRUZ, Rua Waldemar Falcão 121, 40296-710 Salvador, Bahia, Brazil.

The role of cytokines in Leishmania amazonensis experimental infection has not been as well studied as in Leishmania major infection model. Here we investigated the role of interleukin (IL)-4 and PGE(2) in L. amazonensis infection of susceptible BALB/c mice. IL-4 deficient (-/-) or wild-type (+/+) BALB/c mice were infected with different inocula of L. amazonensis. Two weeks after infection with 5x10(6) promastigotes/footpad, the production of interferon (IFN)-gamma upon L. amazonensis antigen stimulation was significantly higher in lymph node cell cultures of IL-4-/- mice than in IL-4+/+ mice. The levels of anti-leishmania IgG2a antibodies were also significantly higher in serum from IL-4-/- mice. In contrast, the levels of IgG1 antibodies were increased in IL-4+/+ mice and almost undetectable in IL-4-/- mice. Despite the increased Th1 response, lesions of IL-4-/- BALB/c mice progressed similarly to those of IL-4+/+ mice upon infection with the 5x10(6) inoculum. However, IL-4-/- mice developed smaller lesions upon infection with 10(5), 10(4) or 10(3) parasites than IL-4+/+ mice. The resistance of IL-4-/- correlated with higher Th1 response, compared to IL-4+/+ upon infection with 10(4)L. amazonensis. IL-4+/+ mice treated with indomethacin, an inhibitor of PGE(2) synthesis, during the first 3weeks of infection developed smaller lesions and lower parasitic load when compared to the control group. The lesions of indomethacin-treated groups contained mostly macrophages without vacuoles and small or absent necrotic areas. These results indicate that IL-4 and PGE(2) are susceptibility factors to L. amazonensis infection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.micinf.2005.11.011DOI Listing
April 2006
-->