Navegando por Assunto "Resposta imune"

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Acesso aberto (Open Access)
Atividade e expressão da metaloprotease GP63 nas espécies Leishmania (Leishmania) amazonensis e Leishmania (Viannia) brasiliensis
(Universidade Federal do Pará, 2021-06) SOARES, Dara da Costa; SILVA, Edilene Oliveira da; http://lattes.cnpq.br/7410116802190343; https://orcid.org/0000-0001-6555-6868
The american cutaneous leishmaniasis (ATL) is a neglected tropical disease caused by protozoa of the genus Leishmania sp. In Brazil, Leishmania (L.) amazonensis and Leishmania (V.) braziliensis are the main pathogenic species. The different strains and species, as well as the immune response of the vertebrate host, are key points in the development of the disease and, consequently, in the different clinical manifestations caused by these protozoa such as localized cutaneous leishmaniasis (LCL), diffuse cutaneous leishmaniasis (LCD) and mucocutaneous leishmaniasis (CML). Leishmania parasites have improved mechanisms with the ability to silence the microbicidal response of infected macrophages through the action of virulence factors such as glycoprotein 63 (GP63). This glycoprotein, which has a zinc- dependent catalytic site, is the main surface metalloprotease of Leishmania and is able to modulate the vertebrate host's immune response by cleaving a wide set of cytosolic substrates. However, due to the need to understand the role and involvement of GP63 in infection processes and different clinical manifestations, it is important to analyze how this molecule is present during these processes. In view of this, the hypothesis of this study is whether there is a difference in the expression of the virulence factor GP63 between two ATL-causing species, Leishmania (Leishmania) amazonensis and Leishmania (Viannia) braziliensis, which cause different clinical manifestations. Therefore, the objective of this work was to analyze the expression and activity of GP63 in the species Leishmania (L.) amazonensis and Leishmania (V.) braziliensis, which are more relevant to the involvement of ATL. The activity of GP63 was analyzed using promastigote forms in the stationary phase (7 days of culture) and they were submitted to analysis of the proteolytic profile through DQ-gelatin (10μg / ml) in fluorimeter (VICTOR Multilabel Plate Reader X) with wavelength of 480-520 nm and by zymography gel containing 0.1% gelatin as substrate. The expression of GP63 was analyzed by Western blot using anti-GP63 antibody. The immunostaining and quantification of the GP63 protein were analyzed by indirect immunofluorescence. This work showed for the first time that the species Leishmania (L.) amazonensis shows greater expression of the glycoprotein 63 kDa compared to the species Leishmania (V.) braziliensis. The greater expression of this protease was also accompanied by an increase in gelatinolytic activity in the analyzed species. These results allow suggesting a correlation in the involvement of this virulence factor between the clinical manifestations that are caused by these two species analyzed in this work.
Acesso aberto (Open Access)
Caracterização da resposta imune citocínica na infecção humana pelo vírus oropouche e sua relação com o padrão de soroconversão e a presença de sintomas
(Universidade Federal do Pará, 2011-12-19) OLIVEIRA, Euzébio de; VASCONCELOS, Pedro Fernando da Costa; http://lattes.cnpq.br/0973550817356564
This thesis is the first global study that researches and analyzes the immune response of cytokine in human infections by Orthobunyavirus Oropuche virus. The study used 320 samples of human serum. Sixty were from the Blood Bank (negative control) and 260 were obtained from two outbreaks of the Oropouche virus in the State of Pará and Amapá (Brazil). The latter was divided into 8 subgroups for better data accuracy. The collected samples were analyzed for clinical data/symptoms with serologic testing by titration of antibodies by the hemagglutination inhibition (IgM/IgG) and the detection cytokines plasma levels by flow cytometry. This allowed for the technical description of cytokine. The data obtained allowed for the observation of the characteristics and the behavior of the cytokines signatures expressed by patients by the presence or not of the virus. This also allowed for the observation of changes to serum through the presence of specific symptoms such as fever, chills, headache and dizziness. This led to the following conclusions a) there is a pattern in the synthesis of pro-inflammatory and regulatory cytokines; b) there is a balance in the profile of the immune response between pro-inflammatory cytokines (Th1) and modulators (Th17); c) an infection by the Oropouche virus alters the production of cytokines in individuals; d) the results also show that whem comparing individuals no responders with early responders, there was an increase of IL-1β and decreased IL- 12; no responders with late responders, there was a decrease of IL-8, and increased IFN-α, IL-23 and IL-17; No responders occurred early responders compared with the increase IL-4 and IFN-g; However, when compared early responders and late responders, decreased IFN-α and IL-6; early responders generally showed a decrease in IL-10 and late responders showed an increase in IL-5; e) The results also show the expression of IL-5 in patients who showed symptoms specific for Oropouche infection (fever, chills, headache and dizziness), suggesting this signal to be directly associated with pathogenesis of the virus; f) there is a need to complement this research with more studies such as those related to the expression of chemokines.
Acesso aberto (Open Access)
Estudo morfológico e imunológico da encefalite induzida pelo vírus juruaçá em modelo murino
(Universidade Federal do Pará, 2013-10-08) FERREIRA, Natalie Chaves; DINIZ JUNIOR, José Antônio Picanço; http://lattes.cnpq.br/1897655177251738
Many studies have been conducted to understand the neuropathogenesis of viral encephalitis from experimental work, however, no experimental studies have been devoted to understanding the neuropathogenesis of members of the Picornaviridae family isolated from bats in the Amazon region. The Juruaçá virus, one of these agents, partially characterized as a member of the Picornaviridae family by Araujo et al. (2006), caused lesions in the brain of neonatal mice with reactive gliosis presence, although not cause cytopathic effect (CPE) in primary cultures of central nervous system (CNS) cells, suggesting that this viral agent is responsible for the death of animals due to an intense immune response. The aim of this study was to investigate the immune response in the CNS and cellular changes caused by Juruaçá virus in newborn albino mice of strain BALB/c from histopathological analysis, microglial activation, and expression of cytokines, nitric oxide (NO) and reactive oxygen species (ROS). Thus, we performed sample processing for histopathology, immunosorbent assay, immunohistochemical and immunofluorescence assays, tests to quantify NO and superoxide radicals, and statistical analysis. Our results demonstrated that the Juruaçá virus induces lesions throughout the brain, with greater intensity in the cortical parenchyma. Immunohistochemical tests showed the presence of viral antigens and reactive microglias distributed throughout the brain and anterior spinal cord. Microglias with amoeboid shape, demonstrating intense activation, were observed in the cerebral cortex, olfactory bulb, anterior olfactory nucleus, midbrain and forebrain near the lateral ventricle. The production of anti-inflammatory cytokines (IL-10 and IL-4) decreased over time, whereas pro-inflammatory cytokines (IL -12, IL- 6, IL- 1β, TNF-α and IFN-γ) increased significantly from the 8th day. Assays for ROS detection showed great superoxide radicals production from the 4th day, as NO production was always lower in the infected animals. Probably, activation of glial cells, especially microglias, and subsequent production of proinflammatory cytokines and ROS promoted a devastating action on the cells of the CNS, which coincides with the intensification of clinical signs. In accordance with what has been explained above, became evident that our results indicate that the Juruaçá virus is responsible for a imprint inflammatory disease that leads to death 100% of infected neonates mice.
Acesso aberto (Open Access)
Resposta imune humoral de bubalinos (Bubalus bubalis) vacinados pela cepa B19 de Brucella abortus
(Universidade Federal do Pará, 2013-08-31) PEREIRA, Ana Patrícia Moreira; CASSEB, Alexandre do Rosário; http://lattes.cnpq.br/6525374874057337; PEREIRA, Washington Luiz Assunção; http://lattes.cnpq.br/9266281009742277
Brucellosis is spread throughout the country, with the highest prevalence for the strain Brucella abortus that despite being endemic presents unevenly among different regions of Brazil. This study aims to evaluate the humoral and immune response of buffalo calves raised in the Middle Amazon Mesoregion, Pará state, vaccinated with B19 strain of B. abortus according the age recommended by the National Program for the Control and Eradication of Brucellosis and Tuberculosis (PNCEBT). Thirty-six female (test group) and six males (control group) aged 3-8 months were selected and monitored. On day 0 of the experiment, blood was collected from all animals, then all females received commercial vaccine with standard-dose sample B19 as recommended by PNCEBT with subsequent blood samples were taken at 30, 60, 90, 120, 150, 180, 210, 330, 360 and 390 days, respectively. The blood serums were evaluated for evidence of agglutination screening through Buffered Acidified Antigen - AAT and the confirmatory test through 2 Mercaptoethanol - 2ME. The results for all samples collected on day 0 were negative in the reaction, however at 30 and 60 days all females were 100% positive through test reaction AAT and titration 1:200, starting the decline through the titration at 90 days in both events. Females at 210 days still present reagents with similar results in both tests, however only one animal remained reactive in both tests up to 360 days. After 390 days of the begin of the experiment 100% of the females had a negative reaction in both events and throughout the experiment males were negative. Thus, by the evaluation of results, vaccination was effective for immunization, as well as an important tool in the prophylaxis of brucellosis in the species studied, as well as the tests applied to the diagnosis of this disease in buffaloes species at regional level.