RESUMO
Vaccination with live attenuated Leishmania parasites such as centrin deleted Leishmania donovani (LdCen-/-) against visceral leishmaniasis has been reported extensively. The protection induced by LdCen-/- parasites was mediated by both CD4+ and CD8+ T cells. While the host immune mediators of protection are known, parasite determinants that affect the CD4+ and CD8+ T cell populations remain unknown. Parasite encoded inflammatory cytokine MIF has been shown to modulate the T cell differentiation characteristics by altering the inflammation induced apoptosis during contraction phase in experimental infections with Leishmania or Plasmodium. Neutralization of parasite encoded MIF either by antibodies or gene deletion conferred protection in Plasmodium and Leishmania studies. We investigated if the immunogenicity and protection induced by LdCen-/- parasites is affected by deleting MIF genes from this vaccine strain. Our results showed that LdCen-/-MIF-/- immunized group presented higher percentage of CD4+ and CD8+ central memory T cells, increased CD8+ T cell proliferation after challenge compared to LdCen-/- immunization. LdCen-/-MIF-/- immunized group presented elevated production of IFN-γ+ and TNF-α+ CD4+ T cells concomitant with a reduced parasite load in spleen and liver compared to LdCen-/-group following challenge with L. infantum. Our results demonstrate the role of parasite induced factors involved in protection and long-term immunity of vaccines against VL.
Assuntos
Leishmania donovani , Vacinas contra Leishmaniose , Leishmaniose Visceral , Parasitos , Animais , Camundongos , Linfócitos T CD8-Positivos , Leishmaniose Visceral/parasitologia , Leishmania donovani/genética , Linfócitos T CD4-Positivos , Camundongos Endogâmicos BALB CRESUMO
BACKGROUND: The worldwide epidemics of diseases as dengue and Zika have triggered an intense effort to repurpose drugs and search for novel antivirals to treat patients as no approved drugs for these diseases are currently available. Our aim was to screen plant-derived extracts to identify and isolate compounds with antiviral properties against dengue virus (DENV) and Zika virus (ZIKV). METHODS: Seven thousand plant extracts were screened in vitro for their antiviral properties against DENV-2 and ZIKV by their viral cytopathic effect reduction followed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method, previously validated for this purpose. Selected extracts were submitted to bioactivity-guided fractionation using high- and ultrahigh-pressure liquid chromatography. In parallel, high-resolution mass spectrometric data (MSn) were collected from each fraction, allowing compounds into the active fractions to be tracked in subsequent fractionation procedures. The virucidal activity of extracts and compounds was assessed by using the plaque reduction assay. EC50 and CC50 were determined by dose response experiments, and the ratio (EC50/CC50) was used as a selectivity index (SI) to measure the antiviral vs. cytotoxic activity. Purified compounds were used in nuclear magnetic resonance spectroscopy to identify their chemical structures. Two compounds were associated in different proportions and submitted to bioassays against both viruses to investigate possible synergy. In silico prediction of the pharmacokinetic and toxicity (ADMET) properties of the antiviral compounds were calculated using the pkCSM platform. RESULTS: We detected antiviral activity against DENV-2 and ZIKV in 21 extracts obtained from 15 plant species. Hippeastrum (Amaryllidaceae) was the most represented genus, affording seven active extracts. Bioactivity-guided fractionation of several extracts led to the purification of lycorine, pretazettine, narciclasine, and narciclasine-4-O-ß-D-xylopyranoside (NXP). Another 16 compounds were identified in active fractions. Association of lycorine and pretazettine did not improve their antiviral activity against DENV-2 and neither to ZIKV. ADMET prediction suggested that these four compounds may have a good metabolism and no mutagenic toxicity. Predicted oral absorption, distribution, and excretion parameters of lycorine and pretazettine indicate them as candidates to be tested in animal models. CONCLUSIONS: Our results showed that plant extracts, especially those from the Hippeastrum genus, can be a valuable source of antiviral compounds against ZIKV and DENV-2. The majority of compounds identified have never been previously described for their activity against ZIKV and other viruses.
Assuntos
Vírus da Dengue , Dengue , Infecção por Zika virus , Zika virus , Animais , Antivirais/química , Chlorocebus aethiops , Dengue/tratamento farmacológico , Humanos , Células VeroRESUMO
Cancer immunotherapy is the most promising trend in oncology, focusing on helping or activating the patient's immune system to identify and fight against cancer. In the last decade, interest in metabolic reprogramming of tumor-associated macrophages from M2-like phenotype (promoting tumor progression) to M1-like phenotypes (suppressing tumor growth) as a therapeutic strategy against cancer has increased considerably. Iron metabolism has been standing out as a target for the reprogramming of tumor-associated macrophages to M1-like phenotype with therapeutic purposes against cancer. Due to the importance of the iron levels in macrophage polarization states, iron oxide nanoparticles can be used to change the activation state of tumor-associated macrophages for a tumor suppressor phenotype and as an anti-tumor strategy.
Assuntos
Nanopartículas , Neoplasias , Humanos , Imunoterapia , Macrófagos , Nanopartículas Magnéticas de Óxido de Ferro , Neoplasias/tratamento farmacológico , Macrófagos Associados a TumorRESUMO
BACKGROUND: In view of the potential immunosuppressive and regenerative properties of mesenchymal stem cells (MSC), we investigated whether transplantation of adipose tissue-derived stem cells (ASC) could be used to control the granulomatous reaction in the liver of mice infected with Schistosoma mansoni after Praziquantel (PZQ) treatment. METHODOLOGY/PRINICPAL FINDINGS: C57BL/6 mice infected with S. mansoni were treated with PZQ and transplanted intravenously with ASC from uninfected mice. Liver morpho-physiological and immunological analyses were performed. The combined PZQ/ASC therapy significantly reduced the volume of hepatic granulomas, as well as liver damage as measured by ALT levels. We also observed that ASC accelerated the progression of the granulomatous inflammation to the advanced/curative phase. The faster healing interfered with the expression of CD28 and CTLA-4 molecules in CD4+ T lymphocytes, and the levels of IL-10 and IL-17 cytokines, mainly in the livers of PZQ/ASC-treated mice. CONCLUSIONS: Our results show that ASC therapy after PZQ treatment results in smaller granulomas with little tissue damage, suggesting the potential of ASC for the development of novel therapeutic approaches to minimize hepatic lesions as well as a granulomatous reaction following S. mansoni infection. Further studies using the chronic model of schistosomiasis are required to corroborate the therapeutic use of ASC for schistosomiasis.
Assuntos
Tecido Adiposo/fisiologia , Terapia Baseada em Transplante de Células e Tecidos/métodos , Hepatopatias/terapia , Fígado/parasitologia , Praziquantel/uso terapêutico , Esquistossomose/tratamento farmacológico , Animais , Citocinas/metabolismo , Modelos Animais de Doenças , Granuloma , Fígado/metabolismo , Fígado/patologia , Hepatopatias/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Schistosoma mansoni , Esquistossomose/patologia , Esquistossomose mansoniRESUMO
BACKGROUND: Several studies have focused on the association between periodontitis and systemic implications; however, the biological mechanisms of the immune responses before and after periodontal therapy involved in this relationship, such as phagocytic functions, remain unclear. OBJECTIVES: This study aimed to investigate whether periodontal treatment improves the phagocytic function of blood monocytes in patients with severe periodontitis. Materials and Methods. A nonrandomized sample of 55 participants was enrolled in the study. Two groups were studied: control (n = 27, healthy subjects without periodontal disease) and patients (n = 27, healthy subjects without periodontal disease) and patients (. RESULTS: Periodontitis induced impaired phagocytosis by monocytes. Phagocytosis at baseline was significantly lower in periodontitis patients [median, 13.2 (range of 7.1 to 20.8) and 60.7 (40.6 to 88.6)] than in controls [27.4 (15.5 to 40.5)] and 98 (68.2 to 122.9)] for nonsensitized or sensitized samples, respectively. After supportive therapy, patients showed a significant enhancement of phagocytic functions [33.7 (14.6 to 53.2) and 108.5 (99.6 to 159.5)] for nonsensitized and sensitized samples, respectively. Periodontal treatment increased the phagocytic capacity to a level similar to that observed in the control group and improved the capacity of phagocytes to produce superoxide anion. CONCLUSIONS: The results suggest that periodontal therapy in patients with severe periodontitis provides a state of homeostasis due to the reestablishment of phagocytic function and increased production of NBT (Regional Registry No. RBR-24T799; Universal Registry No. U1111-1133-5512).
RESUMO
HIV aspartyl protease inhibitors are able to modulate multiple defense mechanisms. However, their influence on the immune response against Leishmania has rarely been investigated. The aim of our study was to investigate whether in vivo treatment with HIV aspartyl protease inhibitors is able to modulate the immune response during Leishmania infection. Using Leishmania (L.) amazonensis-infected mice, we analyzed the disease evolution and parasite load, immunophenotypic profiles of splenic T and B lymphocytes, numbers of lymphoid aggregates in the spleen, percentages of circulating atypical lymphocytes and reactive monocytes, and serum levels of cytokines and nitric oxide (NO) after 30â¯days of oral treatment with lopinavir/ritonavir (LPV/RTV) or atazanavir (ATV). We observed that LPV/RTV and ATV did not modify the disease evolution or parasite load. However, the antiretroviral treatment induced an increase in activated lymphocytes in the spleen and blood, as well as a decrease in CD69 expression in T and B lymphocytes in the spleen. The treatment also resulted in an increase in activated monocytes in the blood. In addition, antiretrovirals decreased levels of IL-17A and increased levels of NO in sera from Leishmania-infected mice. Thus, our results demonstrate for the first time that in vivo treatment with HIV aspartyl protease inhibitors modifies innate and adaptative immune responses during Leishmania infection and suggest that these drugs could change the clinical course of leishmaniasis in HIV infected-individuals.
Assuntos
Inibidores da Protease de HIV/farmacologia , Inibidores da Protease de HIV/uso terapêutico , Leishmaniose/tratamento farmacológico , Animais , Sulfato de Atazanavir/farmacologia , Sulfato de Atazanavir/uso terapêutico , Citocinas/sangue , Feminino , Leishmaniose/sangue , Leishmaniose/parasitologia , Contagem de Leucócitos , Leucócitos/efeitos dos fármacos , Lopinavir/farmacologia , Lopinavir/uso terapêutico , Camundongos Endogâmicos BALB C , Óxido Nítrico/sangue , Ritonavir/farmacologia , Ritonavir/uso terapêutico , Pele/efeitos dos fármacos , Pele/parasitologia , Baço/efeitos dos fármacos , Baço/imunologia , Baço/parasitologiaRESUMO
BACKGROUND AND AIM: Eosinophils are markers of the eosinophilic esophagitis (EoE) disease, and this work aimed to assess whether activation of eosinophils could be a noninvasive test to contribute for EoE diagnosis. METHODS: The activation state of peripheral blood eosinophils in EoE patients and control subjects was assessed based on the morphological aspects of the eosinophil after adherence to slide. Cyclooxygenase-2 and 5-lipoxygenase expressions were evaluated by means of immunofluorescence microscopy to verify if and which eicosanoid pathway is triggered in eosinophils in blood in EoE. RESULTS: The eosinophils of patients with EoE were significantly more activated than those of control individuals. The lowest percentage of normal eosinophils for control subjects was 40%, while the highest percentage of eosinophils of normal aspect for patients with EoE was 32%. Considering 36% as a cutoff for normal eosinophils, this value differentiated all individuals with EoE from individuals without the disease with a sensitivity of 100%, considering the diagnosis of EoE as currently defined. Eosinophils of EoE patients showed higher expression of cyclooxygenase-2 than those of control subjects. CONCLUSIONS: The quantification of morphological changes in eosinophils is a feasible, easy, and reliable manner to identify EoE patients. Therefore, patients with symptoms of esophageal dysfunction showing higher than 36% activated eosinophils in peripheral blood could be a useful way to help definition and diagnostic criterion for EoE.
Assuntos
Esofagite Eosinofílica/diagnóstico , Eosinófilos/imunologia , Adulto , Araquidonato 5-Lipoxigenase/sangue , Biomarcadores/sangue , Estudos Transversais , Ciclo-Oxigenase 2/sangue , Esofagite Eosinofílica/imunologia , Eosinófilos/enzimologia , Eosinófilos/patologia , Feminino , Humanos , Masculino , Adulto JovemRESUMO
Miltefosine is an anticancer drug currently used to treat visceral and cutaneous leishmaniasis, also presents a broad-spectrum of fungicidal and antiamoebae activities. It acts on the metabolism of phospholipids and glycoproteins of the membrane of parasites. Our study aimed to evaluate the effects of miltefosine (0.4 to 50.0 µg/mL) on the phagocytosis and nitric oxide production by macrophages of C57BL/6 mice to clarify the immunomodulatory effects of the drug on macrophages of C57BL/6, strain mice that is biased to Th1 response. Peritoneal macrophages were in vitro treated with miltefosine and phagocytosis of sensitized or nonsensitized Saccharomyces cerevisiae was assessed. NO production was evaluated by Griess reaction. In the concentration of 1.6 µg/mL and 50.0 µg/mL, miltefosine increased phagocytosis of non-opsonized S. cerevisiae in 59.7% and 214.3%, respectively. For phagocytosis through opsonin receptors, miltefosine (50.0 µg/mL) increased the phagocytic index in 208.6% (p=0.04, paired t test). Miltefosine (50.0 µg/mL) decreased in 39.3% NO production by macrophages. However, treatment with miltefosine (50.0 µg/mL) after infection of macrophages with Leishmania amazonensis increased NO production in 73.4% (p=0.01, Wilcoxon test). Our data showed that, besides the antimicrobial effect of miltefosine, the drug showed immunomodulatory effects on macrophages of C57BL/6 mice, improving phagocytosis and decreasing NO production, but was able to increase NO production when macrophages were previously infected with L. amazonensis. These results suggest that miltefosine may favor the better evolution of infectious diseases by improving the innate immune response of macrophages.