928 resultados para Immune Escape
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Sporotrichosis is an infection caused by the dimorphic fungus Sporothrix schenckii. Toll-like receptors (TLRs) play an important role in immunity, since they bind to pathogen surface antigens and initiate the immune response. However, little is known about the role of TLR-2 and fungal surface antigens in the recognition of S. schenckii and in the subsequent immune response. This study aimed to evaluate the involvement of TLR-2 and fungal surface soluble (SolAg) and lipidic (LipAg) antigens in phagocytosis of S. schenckii and production of immune mediators by macrophages obtained from WT and TLR-2 -/- animals. The results showed that TLR-2-/- animals had had statistical lower percentage of macrophages with internalized yeasts compared to WT. SolAg and LipAg impaired phagocytosis and immunological mediator production for both WT and TLR-2-/-. The absence of TLR-2 led to lower production of the cytokines TNF, IL-1β, IL-12 and IL-10 compared to WT animals. These results suggest a new insight in relation to how the immune system, through TLR-2, recognizes and induces the production of mediators in response to the fungus S. schenckii. Copyright © Informa Healthcare USA, Inc.
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In canine visceral leishmaniasis (CVL), the abnormalities most commonly observed in clinical examination on the animals are lymphadenomegaly and skin lesions. Dogs are the main domestic reservoir for the protozoon Leishmania (L.) chagasi and the skin is the main site of contamination by the vector insect. Some protozoa use apoptosis as an immunological escape mechanism. The aim of this study was to correlate the presence of apoptosis with the parasite load and with the inflammatory response in the skin and lymph nodes of dogs naturally infected with Leishmania (L.) chagasi. Thirty-three dogs from the municipality of Araçatuba (São Paulo, Brazil) were used, an endemic area for CVL. Muzzle, ear and abdominal skin and the popliteal, subscapular, iliac and mesenteric lymph nodes of symptomatic (S), oligosymptomatic (O) and asymptomatic (A) dogs were analyzed histologically. The parasite load and percentage apoptosis were evaluated using an immunohistochemical technique. Microscopically, the lymph nodes presented chronic lymphadenitis and the skin presented plasmacytic infiltrate and granulomatous foci in the superficial dermis, especially in the ear and muzzle regions. The inflammation was most severe in group S. The parasite load and apoptotic cell density were also greatest in this group. The cause of the lymphoid atrophy in these dogs was correlated with T lymphocyte apoptosis, thus leaving the dogs more susceptible to CVL. The peripheral lymph nodes presented the greatest inflammatory response. Independent of the clinical picture, the predominant inflammatory response was granulomatous and plasmacytic, both in the skin and in the peripheral lymph nodes. The ear skin presented the greatest intensity of inflammation and parasite load, followed by the muzzle skin, in group S. The ear skin area presented a non-significant difference in cell profile, with predominance of macrophages, and a significant difference from group A to groups O and S. It was seen that in these areas, there were high densities of parasites and cells undergoing apoptosis, in group S. The association between apoptosis and parasite load was not significant in the lymph nodes, but in the muzzle regions and at the ear tips, a positive correlation was seen between the parasite load and the density of cells undergoing apoptosis. The dogs in group S had the highest parasite load and the greatest number of apoptotic cells, thus suggesting that the parasite had an immune evasion mechanism, which could be proven statistically in the skin. © 2012 Elsevier B.V.
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Material surfaces that provide biomimetic cues, such as nanoscale architectures, have been shown to alter cell/biomaterial interactions. Recent studies have identified titania nanotube arrays as strong candidates for use in interfaces on implantable devices due to their ability to elicit improved cellular functionality. However, limited information exists regarding the immune response of nanotube arrays. Thus, in this study, we have investigated the short- and long-term immune cell reaction of titania nanotube arrays. Whole blood lysate (containing leukocytes, thrombocytes and trace amounts of erythrocytes), isolated from human blood, were cultured on titania nanotube arrays and biomedical grade titanium (as a control) for 2 hours and 2 and 7 days. In order to determine the in vitro immune response on titania nanotube arrays, immune cell functionality was evaluated by cellular viability, adhesion, proliferation, morphology, cytokine/chemokine expression, with and without lipopolysaccharide (LPS), and nitric oxide release. The results presented in this study indicate a decrease in short- and long-term monocyte, macrophage and neutrophil functionality on titania nanotube arrays as compared to the control substrate. This work shows a reduced stimulation of the immune response on titania nanotube arrays, identifying this specific nanoarchitecture as a potentially optimal interface for implantable biomedical devices. © 2013 The Royal Society of Chemistry.
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Objectives: To investigate if the participation of Atopobium vaginae, Megasphaera sp. and Leptotrichia sp. in the bacterial community of bacterial vaginosis (BV) is associated with distinct patterns of this condition. Methods: In this cross-sectional controlled study, 205 women with BV and 205 women with normal flora were included. Vaginal rinsing samples were obtained for measuring the levels of pro-inflammatory cytokines and bacterial sialidases. Real-time PCR was used to quantify the BV-associated bacteria and to estimate the total bacterial load using the 16S rRNA. Principal component analysis (PCA) using the measured parameters was performed to compare the BV samples with lower and higher loads of the species of interest. Results: Higher bacterial load (p<0.001), levels of interleukin 1-β (p<0.001) and sialidase activity (p<0.001) were associated with BV. Women with BV and higher relative loads of A vaginae, Megasphaera sp. and Leptotrichia sp. presented increased sialidase activity, but unchanged cytokine levels. PCA analysis did not indicate a different pattern of BV according to the loads of A vaginae, Megasphaera sp. and Leptotrichia sp. Conclusions: Greater participation of A vaginae, Megasphaera sp. and Leptotrichia sp. in vaginal bacterial community did not indicate a less severe form of BV; moreover, it was associated with increased sialidase activity.
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Anaplasma marginale is the most prevalent pathogen of cattle transmitted by ticks in the world. This study aimed to evaluate the risk factors for anaplasmosis in dairy cattle. Fifty dairy cattle from the herd of Empresa de Pesquisa Agropecuaria do Estado do Rio de Janeiro were selected by proportional stratified sampling. The risk factors evaluated were: physiological state, race pattern, number of lactations, milk production, infestation by Rhipicephalus microplus and animal density. Antibody activity against A. marginale was determined using the indirect enzyme-linked immunosorbent assay. The percentual values of seroprevalence for A. marginale were submitted to X2 test, and the level of minimum significance, to keep a factor in the model of logistic regression, was fixated in 5%. It was observed that pregnancy and lactation influenced significantly (p<0.05) in the seropositivity of the animals. Bos indicus animals had 5.21 times more chances of being seropositive than B. taurus animals. Primiparous female had 88% more chances of being seropositive than pluriparous female. Animals with high milk production were 63% more positive than low production animals. When infested by ticks the animals had 39% more chance of being seropositive to A. marginale. Bos indicus animals presented 5.21 times more chance of being seropositive than B. taurus animals. Primiparous females presented 88% more chance of being seropositive than the pluriparous ones. High milk production animals were 63% more positive than the low production ones. When infested by ticks the animals had 39% more chance of being seropositive to A. marginale. High density grazing provided for the animals 3.2 times more chances of being seropositive than low density ones. The herd was classified as erratic to A. marginale, even being placed in a steady enzootic area.
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Brucellosis remains an economic problem in animals and public health. Worldwide ovine brucellosis caused by Brucella ovis is considered a major cause of infertility in sheep. The factors responsible for persistence of the agent are not known, as well as the mechanisms involved in immune defense and possibly the persistence of the agent. Brucella spp. induces moderate inflammatory response. The nature of the intracellular agent stimulates immune response of the type 1 helper T lymphocytes. Studies of the pathogenesis of ovine brucellosis are scarce. Recent developments have shown that the inflammatory response induced by moderate brucelas represent probably the result of an attempt to escape the immune response and suppression of host immune response. Were reviewed by the mechanisms described by brucelas and Brucella ovis for penetration into the host, escape of the immune response and the immune response generated by the infection.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The antibody and cellular immune responses against infectious bronchitis virus (IBV) were evaluated at mucosal sites of chickens after immunization with various doses of an attenuated vaccine at 1 day of age. The correlation of these immune responses with protection of tracheal tissues was evaluated after experimental infection of these birds. Significantly reduced tracheal pathologic effects, measured according to ciliostasis and histology lesions, and reduced viral load were observed only in the full-dose vaccinated group at 5 days post-infection (dpi), while incomplete protection was observed for the subdose vaccinated groups. Moreover, birds of vaccinated groups, especially with full dose, developed higher levels of lachrymal IBV-specific IgG and IgA and increased the expression of cell-mediated immunity (CMI) genes, such as gamma interferon (IFNγ), CD8+ T cell marker, and granzyme homolog A more rapidly. In addition, these humoral and cellular immune responses evaluated at mucosal sites correlated significantly with tracheal protection against homologous IBV challenge in a vaccine dose-dependent manner. The results indicate that IgG, IgA and CD8+ T cell responses developed at mucosal sites after IBV vaccination of day-old chicks, could be taken as good correlates of protection against this virus. © 2013, Mary Ann Liebert, Inc.
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Breeder feed restriction may negatively affect broiler progeny immunity. Sources of trace minerals (TM) with higher bioavailability in breeder diets have been reported to enhance humoral and cellular immunity in broiler progeny. An experiment was conducted to examine the effects of breeder feeding programs and TM dietary sources on maternal antibody transfer and humoral immune response of progeny to a live vaccine against Newcastle disease virus (NDV). Cobb 500 breeders were fed according to 2 feed allocation programs, sigmoid late fast and sigmoid late slow, from 14 to 29 wk of age. From 56 to 62 wk of age, breeders were fed with either inorganic TM or an organic source (OTM) to replace 30% of Cu, Zn, and Mn. Progeny broilers were vaccinated intraocularly with La Sota NDV vaccine at 7 d of age. Blood samples were collected at hatching, 4, and 14 d postvaccination. Serum antibody levels against NDV were assessed by ELISA and cytokine expression by real time PCR. At hatching, late slow breeder progeny fed diets with 30% OTM had higher antibody titers as compared with progeny of breeders fed 100% inorganic TM. Similar results were observed 2 wk postvaccination. Breeder feeding programs and TM sources affected the expression level of IL-4 in NDV vaccinated broiler progeny. It was concluded that breeder feeding programs influenced humoral immune response to NDV vaccine in the broiler progeny, and 30% OTM may increase these responses. © 2013 Poultry Science Association, Inc.
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Some escape and dynamical properties for a beam of light inside a corrugated waveguide are discussed by using Fresnel reflectance. The system is described by a mapping and is controlled by a parameter δ defining a transition from integrability (δ = 0) to non integrability (δ ≠ 0). The phase space is mixed containing periodic islands, chaotic seas and invariant tori. The histogram of escaping orbits is shown to be scaling invariant with respect to δ. The waveguide is immersed in a region with different refractive index. Different optical materials are used to overcame the results. © 2013 Elsevier B.V. All rights reserved.
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The human skin not only provides passive protection as a physical barrier against external injury, but also mediates active surveillance via epidermal cell surface receptors that recognize and respond to potential invaders. Primary keratinocytes and immortalized cell lines, the commonly used sources to investigate immune responses of cutaneous epithelium are often difficult to obtain and/or potentially exhibit changes in cellular genetic make-up. Here we investigated the possibility of using salivary epithelial cells (SEC) to evaluate the host response to cutaneous microbes. Elevated secretion of IFN-γ and IL-12 was observed in the SEC stimulated with Staphylococcus aureus, a transient pathogen of the skin, as mono species biofilm as compared to SEC stimulated with a commensal microbe, the Staphylococcus epidermidis. Co-culture of the SEC with both microbes as dual species biofilm elicited maximum cytokine response. Stimulation with S. aureus alone but not with S. epidermidis alone induced maximum toll-like receptor-2 (TLR-2) expression in the SEC. Exposure to dual species biofilm induced a sustained upregulation of TLR-2 in the SEC for up to an hour. The data support novel application of the SEC as efficient biospecimen that may be used to investigate personalized response to cutaneous microflora. © 2013 Wiley Periodicals, Inc.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em Engenharia Mecânica - FEG
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Pós-graduação em Biociências e Biotecnologia Aplicadas à Farmácia - FCFAR
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)