Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2018-09-12T17:52:35Z No. of bitstreams: 1 2017 - Elisa Domingues Padua.pdf: 1950908 bytes, checksum: d9644f85d3b5935e0ad3f149d04d4f4b (MD5) / Made available in DSpace on 2018-09-12T17:52:35Z (GMT). No. of bitstreams: 1 2017 - Elisa Domingues Padua.pdf: 1950908 bytes, checksum: d9644f85d3b5935e0ad3f149d04d4f4b (MD5) Previous issue date: 2017-07-25 / Despite some reports of the occurrence of Leishmaniasis in felines, the literature is scarce with regard to its research on populations of cats from areas endemic to the disease. In this way, the present study aimed to investigate the possibility of infection in cats by means of a rapid qualitative test of the antibody test in Serop?dica and Itagua?, metropolitan region of Rio de Janeiro, an endemic area for tegumentary and visceral canine leishmaniasis Anti-Leishmania chagasi by indirect immunoenzymatic assay (ELISA) and indirect immunofluorescence (RIFI). For this purpose, blood samples were collected and the serum of 255 cats was sent to the Escola Nacional de Sa?de P?blica (FIOCRUZ). In this population of cats five animals (1.9%, 5/255) were reactive to the rapid test (TR DPP?), 44 (17.3%) had anti-Leishmania spp. Identified by the RIFI. The main clinical signs observed in the seropositive animals were ocular secretion (16/44 - 36%), nasal secretion (16/44 - 36%), weight loss (7/44 - 15.9%), alopecia (6/44 - 13 , 6%) and ulcerated skin lesions (5/44 - 11.3%), in addition to hepatosplenomegaly (2/44 - 4.5%), lymphadenomegaly (5/44 - 11.3%), corneal opacity 2/44 - 4.5%) and gingivitis (2/44 - 4.5%). It was not possible to establish a standardization for the ELISA. Detection of anti-Leishmania spp. in felines, calls attention to this species that must be further investigated in relation to its power as a source of infection in relation to the parasite. / Apesar de alguns relatos da ocorr?ncia de Leishmaniose em felinos, a literatura ? escassa no que diz respeito ? sua pesquisa em popula??es de gatos de ?reas end?micas para a doen?a. Desta forma, o presente estudo teve por objetivo pesquisar, em Serop?dica e Itagua?, regi?o metropolitana do Rio de Janeiro, ?rea end?mica para Leishmaniose tegumentar e visceral canina, a possibilidade de infec??o em gatos, por meio de teste r?pido qualitativo, da pesquisa de anticorpos anti-Leishmania chagasi pelas t?cnicas de ensaio imunoenzim?tico indireto (ELISA) e rea??o de imunofluoresc?ncia indireta (RIFI). Para tanto, foram colhidas amostras de sangue e soro de 255 gatos, os quais foram encaminhados ? Escola Nacional de Sa?de P?blica (FIOCRUZ). Nessa popula??o, cinco gatos (1,9%, 5/255) foram reagentes ao teste r?pido (TR DPP?), 44 (17,3%) apresentaram anticorpos anti-Leishmania spp. identificados pela RIFI. Os principais sinais cl?nicos observados nos animais soropositivos foram secre??o ocular (16/44 ? 36%), secre??o nasal (16/44 ? 36%), emagrecimento (7/44 ? 15,9%), alopecia (6/44 ? 13,6%) e les?o ulcerada na pele (5/44 ? 11,3%), al?m de hepatoesplenomegalia (2/44 ? 4,5%), linfadenomegalia (5/44 ? 11,3%), opacidade de c?rnea (2/44 ? 4,5%) e gengivite (2/44 ? 4,5%). N?o foi poss?vel estabelecer uma padroniza??o para o ELISA. A detec??o de anticorpos anti-Leishmania spp. em felinos chama a aten??o para essa esp?cie que deve ser mais investigada em rela??o ao seu poder como fonte de infec??o em rela??o ao parasito.

Anticorpos recombinantes vêm sendo utilizados como ferramenta diagnóstica por serem produzidos com baixo custo e em larga escala. Partiu-se de um gene sintético que codifica um fragmento de anticorpo (scFv) específico contra a toxina termoestável, com otimização de códons para expressão em Escherichia coli. Esse gene foi amplificado no vetor de clonagem e subclonado em vetor de expressão pET28a. Células E. coli BL21(DE3) foram transformadas com o plasmídeo recombinante e induzidas em meio de expressão. O fragmento de anticorpo obtido estava contido na fração insolúvel, portanto foi submetido a purificado por cromatografia de afinidade ao níquel na presença de ureia, seguido de renaturação. A molécula se apresentou funcional e sem reatividade com inespecífica por ensaios de imunofluorescência e ELISA. Além disso, mostrou-se estável quando armazenada a 4ºC, sendo assim uma ferramenta promissora para ser utilizada no diagnóstico de ETEC para detecção da toxina ST. / Recombinant antibodies have been used as diagnostic tools since they can be produced at low cost and on a large scale. A synthetic gene encoding an antibody fragment (scFv) specific for the heat-stable toxin (ST) with optimized codon for Escherichia coli expression was employed. This gene was amplified in the cloning vector and subcloned into pET28a expression vector. E. coli BL21(DE3) cells were transformed with the recombinant plasmid and induced. Large amounts of antibody fragment were found in the insoluble fraction. Thus it is submitted to nickel-affinity chromatography in urea presence, followed by refolding step. By immunofluorescence assay and ELISA, the obtained antibody showed to be functional with no cross-reaction to the negative controls. Furthermore, it was stable when stored at 4 °C, therefore a promising tool for ETEC diagnosis detecting the ST toxin.

abstract: Measurements of different molecular species from single cells have the potential to reveal cell-to-cell variations, which are precluded by population-based measurements. An increasing percentage of researches have been focused on proteins, for its central roles in biological processes. Immunofluorescence (IF) has been a well-established protein analysis platform. To gain comprehensive insights into cell biology and diagnostic pathology, a crucial direction would be to increase the multiplexity of current single cell protein analysis technologies. An azide-based chemical cleavable linker has been introduced to design and synthesis novel fluorescent probes. These probes allow cyclic immunofluorescence staining which leads to the feasibility of highly multiplexed single cell in situ protein profiling. These highly multiplexed imaging-based platforms have the potential to quantify more than 100 protein targets in cultured cells and more than 50 protein targets in single cells in tissues. This approach has been successfully applied in formalin-fixed paraffin-embedded (FFPE) brain tissues. Multiplexed protein expression level results reveal neuronal heterogeneity in the human hippocampus. / Dissertation/Thesis / Doctoral Dissertation Chemistry 2019

Immunofluorescence assays are capable of both detecting the amount of a protein and the location of the protein within a cell or tissue section. Unfortunately, the traditional technique is not capable of detecting concentrations on the nanoscale. Also, the technique suffers from non-specific attachment, which can cause false-positives, as well as photobleaching when detecting lower concentrations is attempted. There is also a time constraint problem since the technique can take from many hours to a few days in some cases. In this work, metal-enhanced fluorescence (MEF) is used to lower the detection limit and reduce photobleaching. Unfortunately, MEF also increases the intensity of non-specifically bound proteins (NSBPs). Therefore, a surface acoustic wave (SAW) device is used to remove the more weakly bound NSBPs. Previously, this has been shown on lithium niobate, but it is used with a quartz substrate in this work. The SAW device is also used to cause micro-mixing which speeds the process up significantly. In this research, it was found that silver nanocubes can lower the detection limit down to below 1 ng/mL. Quartz SAW devices are shown to remove NSBPs at a power of 10 mW applied for five minutes. Micro-mixing is shown to be improved by a factor of six at 10 mW for 10 minutes by saturating the antibody used in this research, which takes 1 hour without micro-mixing. Finally, all three components are combined. In this work, the whole device is used to detect 50 ng/mL. After micro-mixing, the intensity is the same as with MEF, and, after removal, it has been lowered by 7 a.u.

No description available.

Specific antibodies are invaluable tools for proteomics research. The availability of thoroughly validated antibodies will help to improve our understanding of protein expression, localization and function; fundamental processes and features of all living organisms. The objectives of the studies in this thesis were to develop high-throughput methods to facilitate the generation and purification of monospecific antibodies, and to address problems associated with antigen selection for difficult target proteins and subsequent validation issues. In the first of the studies, it was demonstrated that antibodies specific to human proteins could be generated in a high-throughput manner using protein epitope signature tags (PrESTs) as both antigens and affinity ligands. A previously developed purification process was adapted to a high-throughput format and this, in combination with the development of a protein microarray assay, resulted in monospecific antibodies that were used for profiling protein expression in 48 human tissues. Data obtained in these analyses suggest that a complete Human Protein Atlas should be attainable within the next ten years. In order to reduce the number of animals needed for such a massive project, and improve the cost-efficiency of antibody generation, a multiplex immunization strategy was developed in a further study. Antisera from rabbits immunized with mixtures of two, three, five and up to ten different PrESTs were successfully purified and analyzed for specificity using protein arrays. Almost 80% of the animals immunized with up to three PrESTs yielded antibodies towards all the PrESTs administered, and they yielded comparable immunohistochemical staining patterns (of consecutive human tissue sections) to those of antibodies obtained from traditional single PrEST immunizations. Proteins with highly similar sequences to other proteins present a major challenge for the proteome-wide generation of antibodies. In another study, Cytokeratin-17 which displays high sequence similarity to closely related members of the intermediate filament family, was used as a model and the specificity and cross-reactivity of antibodies generated against this target were investigated using epitope mapping in combination with comparative IHC analyses. Antibodies identified by epitope mapping as binding to the most unique parts of the Cytokeratin-17 PrESTs also showed the most Cytokeratin-17-like staining pattern, thus further supporting the strategy of using sequence identity scores as the main criteria for PrEST design. An alternative antigen design strategy was investigated for use in raising antibodies towards G-proteincoupled receptors (GPCRs). The extracellular loops and N-terminus of each of three selected GPCRs were assembled to form single antigens and the resulting antibodies were analyzed by flow cytometric and confocal microscopic analyses of cell lines over-expressing the respective receptors. The results from both flow cytometric and immunofluorescence analyses showed that the antibodies were able to bind to their targets. In addition, the antibodies were used successfully for the in situ analysis of human brain and pancreatic islet cells. / QC 20100727

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.

Soluble amyloid-beta (Aβ) aggregates, including Aβ protofibrils, play a central role in Alzheimer’s disease (AD) and constitute a potential diagnostic biomarker and a therapeutic target. Aβ protofibrils promote synapse dysfunction and neurodegeneration, but the mechanisms behind these effects remain unclear. The aim of this thesis was to increase the knowledge of Aβ protofibrils in AD pathology. When measuring low abundant antigens, such as soluble Aβ aggregates, in plasma and CSF by immunoassays, there is a possibility of interference by heterophilic antibodies (HA). In paper I, we show that HA generate false positive signals, by cross-binding the assay antibodies, when plasma and CSF from AD patients and healthy controls were analyzed for soluble Aβ aggregates, using sandwich ELISAs. Natural anti-Aβ antibodies exist in AD patients and healthy individuals. Circulating Aβ and anti-Aβ antibodies may form immune complexes, masking epitopes on the anti-Aβ antibody, which makes the anti-Aβ antibody concentration difficult to measure. In paper II, the ELISpot technique enabled us to successfully measure B cell production of anti-Aβ antibodies. Our results show that anti-Aβ protofibril antibody production is present in both AD patients and healthy individuals, but is significantly higher in AD patients, indicating that the immune system attempt to eliminate the toxic Aβ species. Insufficient lysosomal degradation is proposed to cause sporadic AD. In paper III, we used a co-culture system of astrocytes, neurons and oligodendrocytes, to clarify the role of astrocytes in Aβ protofibril clearance. Astrocytes are the most prominent glial cell type in the brain, but their role in AD remains elusive. We found that astrocytes effectively engulf, but inefficiently degrade Aβprotofibrils. This result in a high intracellular load of toxic, partly N-terminally truncated Aβ and lysosomal dysfunction. Moreover, we found that secretion of microvesicles, containing N-terminally truncated Aβ, induce neuronal apoptosis. In paper IV, we show that treatment with the protofibril selective antibody mAb158 lead to enhanced Aβ clearance and thereby prevent Aβ neurotoxicity. Taken together, this thesis contributes with important knowledge on the role of Aβ protofibrils in AD pathogenesis and technical aspects that should be considered when measuring Aβ in human tissues.

Orientador: Júlio Defaveri / Resumo: A paracoccidioidomicose (Pbmicose) é micose sistêmica causada pelo fungo dimórfico Paracoccidioides brasiliensis, que acomete principalmente trabalhadores rurais do sexo masculino. A doença tem como principais manifestações clínicas a forma aguda/subaguda e a forma crônica. Métodos sorológicos têm considerável valor na Pbmicose e diferentes testes têm sido utilizados no diagnóstico e monitoramento da resposta do paciente ao tratamento. O objetivo deste estudo foi avaliar a IFI, a ID e o ELISA antes e após introdução do tratamento de pacientes com a forma aguda/subaguda e a forma crônica da Pbmicose. Para cada teste, os seguintes parâmetros foram avaliados: sensibilidade (SE), especificidade (EP), valor preditivo positivo (VPP), valor preditivo negativo (VPN) e eficiência (EF). No período pré-tratamento a IFI teve SE=92,3%, VPP= 87,5%, VPN= 92% e EF=88,6%. A ID teve SE=94,93%, VPP=97,4%, VPN=95% e EF=96,2%. Para o ELISA, SE=100%, VPP=95%, VPN=100% e EF=97,4%. No grupo de doadores de sangue, a EP da IFI, da ID e do ELISA foram, respectivamente, de 93,3%, 100% e 100%. Em soros de pacientes com outras micoses sistêmicas (histoplasmose, criptococose, actinomicose, aspergilose e adiaspiromicose), as EP para os testes foram de 60%, 90% e 80%, respectivamente. Durante o tratamento, maior correlação foi obtida entre a ID e o ELISA (r= 0,61591, p<0,05), obtendo-se baixas correlações com a IFI. O tempo necessário para negativar o ELISA (Md= 20,0 meses) foi maior do que a ID (Md= 13,5 meses). O ELISA se negativou em geral nove meses após a ID, o que sugere que este teste passe a ser um referencial para suspensão do tratamento de manutenção. Devido à sua elevada sensibilidade, especificidade, VPP, VPN e eficiência, o ELISA deve ser incluído na rotina sorológica de pacientes com Pbmicose. / Abstract: Pararaccidioidomycosis (Pbmycosis) is a systemic mycosis caused by the dimorphic fungus Paracoccidioiodes brasiliensis, which often affects rural workers, usually male adults. The overt disease is manifested by two clinical forms, acute/subacute and chronic forms. Serological methods are of considerable value in Pbmycosis, and various tests has been utilized in the diagnostic and monitoring the patient's response to treatment. The aim of this study was to evaluated the reliability of the double immunodiffusion test (ID), indirect immunofluorescence (IIF) and immunoenzymatic assay (ELISA) in the pre-treatment and during the period of treatment of patients with acute/subacute and chronic forms of Pbmycosis. For each test the following parameters were evaluated: Sensitivity (SE), Specificity (SP), Positive and Negative Predictive Values (PPV and NPV) and Efficiency (EF). In the pre-treatment period these values for IFI were SE=92.3%, PPV=87.5%, NPV=92% and EF=88.6%. For ID: SE=94.9%, PPV=97.4%, NPV=95% EF=96.2%. For ELISA: SE=100%, PPV=95%, NPV=100% and EF=97.4%. In the group of blood donors, for IFI, ID and ELISA the ES were, respectively, 93.3%, 100% and 100%. In patients with other deep mycosis (histoplasmosis, cryptococcosis, actinomycosis, aspergillosis and adiaspiromycosis) the ES for these tests were respectively 60%, 90% and 80%. During the period of treatment, the highest correlation was observed between ID and ELISA (r= 0,61591, p<0,05), and the lowest correlations with IFI. The time elapsed to negative the ELISA was larger (Md=20 months) than for ID (Md= 13,5 meses). In overall, the ELISA negativated nine months after ID. This result suggests that the ELISA may be a referential test to monitoring the time for interruption of the treatment in Pbmycosis. Moreover, owing to its high values of SE, SP, PPV, NPV and EF, ELISA should be included in the serological routine for patients with Pbmycosis. / Mestre

Ebola virus (EBOV) causes severe disease in humans characterized by high case fatality rates and significant immune dysfunction. A hallmark of EBOV infection is the formation of viral inclusions in the cytoplasm of infected cells. These inclusions contain the EBOV nucleocapsids and are sites of viral replication and nucleocapsid maturation. Although there is growing evidence that viral inclusions create a protected environment that fosters EBOV gene expression and genome replication, little is known about their role in the host response to infection. The cellular stress response is an antiviral strategy that leads to stress granule (SG) formation and translational arrest mediated by the phosphorylation of the alpha subunit of eukaryotic translation initiation factor 2 (eIF2α). Related to this response is the post-transcriptional regulation of RNA mediated by stability elements called AU-rich elements (AREs) and their associated binding proteins (ARE-BPs), many of which are found in SGs. Because these processes have antiviral implications, many viruses have evolved strategies to interfere with SG formation, or appropriate ARE-BPs to benefit viral replication. However, it is unknown if EBOV interacts with these cellular systems. Here, we show that SG proteins were sequestered within EBOV inclusions where they formed distinct granules that colocalized with viral RNA. The inclusion-bound aggregates were not canonical SGs, and did not lead to translational arrest in infected cells. EBOV did not induce cytoplasmic SGs at any time post infection, but was unable to overcome SG formation induced by additional stressors. Despite the sequestration of SG proteins, canonical SGs did not form within inclusions. At high levels of expression, viral protein 35 (VP35), the viral polymerase co-factor that also mediates various immune evasion functions, disrupted SGs formation independently of eIF2α phosphorylation. Finally, we found that the cellular ARE-BP tristetraprolin (TTP) specifically targeted the 3’untranslated region (UTR) of the viral nucleoprotein (NP) mRNA and promoted its degradation. Interestingly, TTP was not found within viral inclusions, leading us to speculate that inclusions might serve to prevent viral RNA from encountering TTP. These results indicate that EBOV interacts with the cellular stress response and associated RNA regulatory proteins in ways that promote viral replication.