Avaliação das propriedades farmacológicas de polissacarídeos do fungo Scleroderma nitidum

Several pharmacological properties have been attributed to isolated compounds from mushroom. Recently, have these compounds, especially the polysaccharides derived from mushrooms, modulate the immune system, and its antitumor, antiviral, antibiotic and antiinflammatory activities. This study assesses the possible pharmacological properties of the polysaccharides from Scleroderma nitidum mushroom. The centesimal composition of the tissue showed that this fungus is composed mainly of fibers (35.61%), ash (33.69%) and carbohydrates (25.31%). The chemical analysis of the polysaccharide fraction showed high levels of carbohydrates (94.71%) and low content of protein (5.29%). These polysaccharides are composed of glucose, galactose, mannose and fucose in the following molar ratios 0.156, 0.044, 0.025, 0.066 and the infrared analysis showed a possible polysaccharide-protein complex. The polysaccharides from Scleroderma nitidum showed antioxidant potential with concentration-dependent antioxidant activity compared to ascorbic acid. The analysis scavenging of superoxide radical and inhibition of lipid peroxidation showed that the polysaccharides from S. nitidum have an IC50 of 12.70 mg/ml and EC50 10.4 μg/ml, respectively. The antioxidant activity was confirmed by the presence of reducing potential of these polysaccharides. The effect of these polymers on the inflammatory process was tested using the carrageenan or histamine-induced paw edema model and the sodium thioglycolate or zymosan-induced model. The polysaccharides were effective in reducing edema (73% at 50 mg/kg) and cell infiltrate (37% at 10 mg/kg) in both inflammation models tested. Nitric oxide, a mediator in the inflammatory process, showed a reduction of around 26% at 10 mg/kg of body weight. Analysis of pro- and anti-inflammatory cytokines showed that in the groups treated with polysaccharides from S. nitidum there was an increase in cytokines such as IL-1ra, IL-10, and MIP-1β concomitant with the decrease in INF-γ (75%) and IL-2 (22%). We observed the influence of polysaccharides on the modulation of the expression of nuclear factor κB. Thus, polysaccharides from S. nitidum reduced the expression of NF-κB by up to 64%. The results obtained suggest that NF-κB modulation is one of the possible mechanisms that explain the anti-inflammatory effect of polysaccharides from the fungus S. nitidum.

O papel modulatório do ferro sobre a resposta imune na Leishmaniose Visceral

Iron is an essential element for many cellular functions, including the immune response against intracellular pathogens. In this study, we aimed evaluate the effect of iron on IRP2, IFN-γ, TNF-α, IL-6, IL-10, MIG and IP10 expression in PBMC and assess the effect of the spleen parasite load on the expression of these genes in the spleen of L. infantum naturally infected dogs. Blood sample from 7 DTH+ donor was collected and PBMC was obtained. The cells were cultivated in absence (iron chelator desferroximane, DFO 10 μM supplemented media) or in presence of iron (hemin 6 mM) for 1 h, followed by stimulation with Leishmania infatum antigen for 4 h. 44 dog spleen samples were obtained and parasite load in this organ was determinate by qPCR. Gene expression was analyzed by qPCR and cytokine production quantified by flow cytometry. In antigen stimulated cells, genes involved in immune response are significantly more expressed in presence of iron. T CD4+ and TCD8+ lymphocytes produces IFN-γ, TNF-α and IL-10 possibly in iron dependent pathway. Monocytes antigen stimulated reduced TNF-α, IL-6 and IL-10 production in presence of iron. We found spleen of infected dogs IRP2 expression increases according to parasite load in that organ, while an inverse profile was found for IFN-γ, TNF-α e IL-10 expression. These results suggest that T lymphocytes depends on iron to produce IFN-γ, TNF-α and IL-10, while iron seems to inhibit cytokine production in monocytes. So, we propose an immunoregulatory mechanism carried out by iron during L. infantum infection in humans and dogs

The effect of phospholipase A2 from Crotalus durissus collilineatus on Leishmania (Leishmania) amazonensis infection

In this study, the effect of phospholipase A2 (PLA2) derived from Crotalus durissus collilineatus was evaluated in vitro and in vivo on experimental cutaneous leishmaniasis. The promastigote and amastigote forms treated with PLA2 presented increased growth rate. In vivo studies showed that PLA2-treated Leishmania (Leishmania) amazonensis promastigotes increased the size of lesions in BALB/c mice, and histopathological analysis showed numerous necrotic regions presenting a higher density of polymorphonuclear, mononuclear, and amastigote cells. Additionally, infected macrophages treated with PLA2 were able to generate prostaglandin E2 (PGE2). Cytokine quantification showed that the supernatant from infected macrophages presented moderate and high amounts of IL-2 and IL-10, respectively. However, in PLA2-treated infected macrophages, suppression of IL-2 levels occurred, but not of IL-10 levels. Observation also revealed that both the supernatant and lysate of L. (L.) amazonensis promastigotes exhibited PLA2 activity, which, in the presence of dexamethasone, showed no reduction in their activities; while glucocorticoid maintained the ability of promastigote forms to infect macrophages, which presented values similar to controls. In conclusion, the results indicate that PLA2 may be a progression factor for cutaneous leishmaniasis, since the PLA2 effect suppressed IL-2 levels and generated PGE2, an inflammatory lipid mediator.

Humoral and cellular immune response generated by different vaccine programs before and after Salmonella Enteritidis challenge in chickens

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Diapocynin versus apocynin as pretranscriptional inhibitors of NADPH oxidase and cytokine production by peripheral blood mononuclear cells

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The role of apoptosis in the antigen-specific T cell hyporesponsiveness of paracoccidioidomycosis patients

Paracoccidioidomycosis is a deep endemic mycosis associated with an antigen-specific immunodeficiency. To examine the role of apoptosis in this immunodeficiency, peripheral blood mononuclear cells (PBMC) of patients with paracoccidioidomycosis and controls were stimulated with the main antigen of Paracoccidioides brasiliensis (gp43) and an unrelated fungal antigen (from Candida albicans, CMA) and analyzed for annexin V and propidium iodide staining by flow cytometry. Control PBMC proliferated well with both antigens. Patients' PBMC proliferated only with CMA, but presented higher levels of apoptosis with gp43 and CMA than in their own unstimulated cultures. Moreover, gp43-triggered apoptosis in control PBMC was lower than in those of the patients. Thus, patient but not control gp43-stimulated T cells apparently remained anergized and subsequently underwent apoptosis. While CMA-induced apoptosis is likely triggered by activation-induced cell death, this is apparently not the case in gp43-induced apoptosis because of the lack of cell cycling and IL-2 in the gp43-stimulated cultures. However, higher IL-10 levels were found in gp43-stimulated patient PBMC cultures. Addition of a neutralizing anti-IL-10 antibody to the cultures resulted in increased apoptosis levels only in gp43-stimulated patient PBMC cultures. Our results suggest that apoptosis plays a role in the patients' antigen-specific hyporesponsiveness and that IL-10 may have an antiapoptotic role. (C) 2002 Elsevier B.V. (USA).

Dermatophyte-host relationship of a murine model of experimental invasive dermatophytosis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Modulation of macrophage cytokine profiles during solid tumor progression: susceptibility to Candida albicans infection

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ativação local da rota da quinurenina por moduladores inflamatórios durante a meningite bacteriana.

Activation of the kynurenine (KYN) pathway (KP) by modulators of immune system has been observed during several neurological diseases. Here we assessed the association of chemo-/cytokine levels with the concentration of KP metabolites in cerebrospinal fluid (CSF) and plasma samples from patients with bacterial meningitis (BM). All samples were collected from 42 patients diagnosed with acute bacterial meningitis (ABM), aseptic meningitis, tuberculous meningitis and patients without infection neurological disorders. CSF and plasma concentration of metabolites from the KP was assessed by high pressure liquid chromatography (HPLC) and cytokines and chemokines by Bio-plex 200 suspension array system. Concentrations of the KP metabolites KYN and kynurenic acid (KYNA) were significantly higher in CSF of patients with ABM compared to other groups. Tryptophan (TRP), anthranilic acid (AA), 3-hydroxykynurenine (3HK) and 3-hydroxyanthranilic acid (3HAA) did not show statistical significance, although some of them presented a good accumulation during ABM. The expression of TNF-alpha, IL-6, IL-1beta, IFN-gamma, IL-10, IL-1 receptor antagonist (IL-1Ra), MIP-1alpha, MIP-1beta, MCP-1 and G-CSF was about 100-fold higher in CSF from ABM patients than other infected groups. In all CSF and plasma samples, the concentration of IL-2, IL-12(p70), IL-4, IL-8 and GM-CSF was not significant. ABM still showed significant concentrations of IL-6, IL-10, IL-1Ra and MCP-1 in plasma samples. Based on the comparison of KP metabolites concentrations between plasma and CSF samples we conclude that the activation of the tryptophan pathway upon BM occurs within the brain. This increase in KP metabolites is most due to activation of the KP by molecules as IFN-gamma and TNF-alpha in response to infection.

Experimental infection with Leishmania chagasi in immunosuppressed Balb/c mice: cytokines and parasite burdens

The immune response in leishmaniasis may result in a polarization of the T lymphocyte subpopulation, altering cell phenotype and resulting in immune protection or disease exacerbation. Leishmania may persist in the body either during asymptomatic infections or after treatment, which represents high risk under immunosuppression. The objective of this study was to evaluate the effect of infection with immunosuppression by dexamethasone associated with pentoxifylline on animal weight, spleen weight, spleen and hepatic parasitic load and immunopathology, as well as the IFN-gamma and IL-10 production in spleen cell culture of Balb/c mice infected with Leishmania chagasi. The infection did not cause body weight gain in animals, but both the weight and size of the spleen were increased. The immunosuppression using dexamethasone associated with pentoxifylline affected body weight gain and spleen weight and size in both infected and non-infected animals. The immunosuppression did not significantly alter the course of the splenic or hepatic parasite burden. Dexamethasone and pentoxifylline significantly affected cytokine production, but did not influence the Th1/Th2 ratio in infected animals.

Assessment of cytokine values in serum by RT-PCR in HIV-1 infected individuals with and without highly active anti-retroviral therapy (HAART)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Intestinal parasitic infections in HIV/AIDS patients: epidemiological, nutritional and immunological aspects

This study applied a socioeconomic questionnaire designed to evaluate the frequency of intestinal parasites and characterize epidemiological, nutritional, and immunological variables in 105 HIV/AIDS patients - with and without parasitic infections, attending the Day Hospital in Botucatu, UNESP, from 2007 to 2008. Body mass index was calculated and the following tests performed: parasitological stool examinations; eosinophil, IgE, CD4(+) T and CD8(+) T lymphocyte cell counts; albumin test; viral load measure; and TNF-alpha, IFN-gamma, IL-2, IL-5 and IL-10 cytokine levels. Results were positive for parasitic intestinal infections in 12.4% of individuals. Most patients had good socioeconomic conditions with basic sanitation, urban dwellings, treated water supply and sewage, good nutritional and immunological status and were undergoing HAART. Parasites were found at the following frequencies: Entamoeba - five patients (38.5%), Giardia lamblia-four (30.7%), Blastocystis hominis-three (23.0%), Endolimax nana-two (15.4%), and Ascaris lumbricoides - one (7.7%). There were no significant differences between the two groups for eosinophils, albumin, IgE, CD4(+) T and CD8(+) T lymphocytes, INF-gamma, IL-2, or IL-10. Most patients also showed undetectable viral load levels. Significant differences were found for TNF-alpha and IL-5. These results show the importance of new studies on immunodeficient individuals to increase understanding of such variables.

Interleukin-6 treatment enhances human monocyte permissiveness for Paracoccidioides brasiliensis growth by modulating cytokine production

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Experimental infection of Leishmania chagasi in immunosuppressed balb/c mice: cellular immune response and parasite burden

The immune response to leishmaniasis can result in a polarization of a subpopulation of T lymphocytes, which leads to a different cell phenotype and results in immune protection or exacerbation of the disease. Leishmanias persist in the body both in asymptomatic infections and after treatment, representing risks in terms of immunosuppression. The objective of this study was to evaluate the effects of infection and immunosuppression by dexamethasone associated with pentoxifylline on animal weight, spleen weight, the parasitic load in the spleen and liver, as well as the production of IFN-gamma and IL-10 in spleen cell culture of Balb/c mice infected with Leishmania chagasi. The infection did not alter animal weight gain, but spleen weight and size increased. The immunosuppression, induced by dexamethasone associated with pentoxifylline, affected animal weight gain and weight and size of the spleen (in infected and not infected animals). The immunosuppression did not significantly alter the course of the parasite burden in the spleen and liver. Dexamethasone and pentoxifylline affected the studied cytokine production, but not influenced on Th1/Th2 response in infected animals.

Hepatoprotective and anti-inflammatory effects of silibinin on experimental preeclampsia induced by 1-NAME in rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)