A estrongiloidíase é uma infecção intestinal causada pelo nematódeo Strongyloides stercoralis. A maioria dos casos evolui para um quadro crônico benigno; entretanto pode haver hiperinfecção e disseminação, sobretudo em pacientes imunodeprimidos. Os métodos parasitológicos convencionais apresentam baixa sensibilidade e, com isso, os testes sorológicos podem representar uma boa alternativa para o diagnóstico dessa helmintíase. O presente trabalho tem como objetivo avaliar as técnicas de RIFI, ELISA e WB para o diagnóstico da estrongiloidíase em pacientes candidatos a transplante. Para validação dos testes, foram utilizadas amostras de soros de pacientes imunocompetentes (positivos para S. stercoralis, positivos para outras parasitoses e negativos). Foram utilizadas amostras de fezes e soros de pacientes candidatos a transplante, a saber: 50 para transplante renal; 50 para transplante de fígado; 50 para transplante de medula óssea. As amostras fecais de todos os pacientes foram analisadas pelas técnicas de sedimentação espontânea, Rugai, e cultura em placa de ágar. Para a execução das técnicas sorológicas foram utilizadas como fonte de antígeno larvas filarioides de S. venezuelensis. Para a RIFI, os soros foram diluídos a 1:40 em tampão PBS-TM e o conjugado anti-IgG humano marcado com fluoresceína diluído 1:500 em PBS acrescido de 4% de azul de Evans, sendo realizada a leitura em microscópio de imunofluorescência, utilizando as objetivas de 20X e 40X. Para a técnica ELISA foram utilizadas placas poliestireno sensibilizadas com 10?g de antígeno (frações solúveis salina e alcalina), soro dos indivíduos diluídos a 1:200 em PBS 0,05% Tween 3% de leite (PBS-TM) e conjugado (anti-IgG humana peroxidase) em PBS-TM. As amostras foram consideradas positivas quando o índice ELISA foi maior que 1. Para a técnica de WB, os soros foram diluídos 1:100 em Tris-HCl 5% de leite (TM) e o conjugado (anti IgG-humana peroxidase) em PBS-TM. Dos 150 pacientes candidatos a transplante analisados, 9,3% (n=14) foram positivos pelas técnicas parasitológicas, sendo que a cultura em placa de ágar detectou 6,6% (n=10). Na RIFI a soropositividade para detecção da infecção por S. stercoralis foi de 16,6% (n=25), sendo, 22% transplante renal, 18% hepático e 10% medula óssea. Pela técnica ELISA a soropositividade foi de 11,3% (n=17), sendo 14% nos pacientes candidatos a transplante renal, 14% hepático e 3% medula óssea, utilizando o antígeno alcalino, e 24,6% (n=37), sendo 18% nos pacientes candidatos a transplante renal, 50% hepático e 6% medula óssea, utilizando o antígeno salino. Pela técnica WB a soropositividade foi de 20,6% (n=31), sendo 18% nos pacientes candidatos a transplante renal, 32% hepático e 12% medula óssea, utilizando o antígeno alcalino, e 18,6% (n=28) sendo 10% nos pacientes candidatos a transplante renal, 14% hepático e 32% medula óssea, utilizando o antígeno salino. A utilização de técnicas imunodiagnósticas pode ser indicada na triagem de pacientes em fila de transplante, devendo-se levar em conta as limitações de reações sorológicas em pacientes imunodeprimidos / Strongyloidiasis is an intestinal infection caused by the nematode Strongyloides stercoralis. Most cases progress to a benign chronic condition; however hyperinfection and dissemination may occur, especially in immunocompromised patients. Conventional parasitological methods have low sensitivity and, thus, serological tests may be a good alternative for the diagnosis of this helminthiasis. The aim of this study was to evaluate RIFI, ELISA and WB techniques for the diagnosis of strongyloidiasis in patients candidates for transplants. In order to validate the tests samples of sera from immunocompetent patients (positive for S. stercoralis, positive for other parasitosis, and negatives) were used. Feces and sera samples of patients candidates for transplants were used as follows: 50 for renal transplant, 50 for liver transplant, 50 for bone marrow transplant. Fecal samples of all patients were analyzed by spontaneous sedimentation, Rugai and Agar plate culture techniques. Filarioid larvae of S. venezuelensis were used as source of antigen for serological tests. For RIFI, sera were diluted 1:40 in PBS-TM buffer and human anti-IgG conjugate labeled with fluorescein was diluted 1:500 in PBS with 4% Blue Evans, reading being performed in immunofluorescence microscope using 20X and 40X objectives. For ELISA technique polystyrene plates sensitized with 10?g of antigen (saline and alkaline soluble fractions), individual sera diluted at 1:200 in PBS 0.05% Tween 3% of milk (PBS-TM) and conjugate (human anti-IgG peroxidase) in PBS-TM were used. Samples were considered positive when ELISA index was higher than 1. For WB technique, sera were diluted in Tris-HCl 5% of milk (TM) and conjugate (human anti-IgG peroxidase) in PBS-TM. From 150 patients candidates for transplants analyzed 9.3% (n=14) were positive by parasitological techniques, agar plate culture detected 6.6% (n=10). In RIFI seropositivity for S. stercoralis infection detection was 16.6% (n=25) being 22% renal transplant, 18% hepatic and 10% for bone marrow. By ELISA technique seropositivity was 11.3% (n=17), being 14% in patients candidates for renal transplant, 14% hepatic and 3% bone marrow, using alkaline antigen and 24.6% (n=37), being 18% in patients candidates for renal transplant, 50% hepatic and 6% bone marrow, using saline antigen. By WB technique seropositivity was 20.6% (n=31), being 18% in patients candidates for renal transplant, 32% hepatic and 12% bone marrow, using alkaline antigen, and 18.6% (n=28) being 10% in patients candidates for renal transplant, 14% hepatic and 32% bone marrow, using saline antigen. Application of immunodiagnostic techniques could be indicated in screening of patients in transplant waiting list, however limitations of serological reactions in immunodepressed patients should be considered

Cryptococcus sp é um fungo saprófita, cosmopolita, que causa micose sistêmica, geralmente, subaguda ou crônica, conhecida, sobretudo, por sua localização meníngea, após aquisição da infecção por via respiratória Embora seja ubíquo, a criptococose ocorre predominantemente em indivíduos imunodeficientes e podendo ocorrer, também, em indivíduos imunocompetentes. Os estudos experimentais e em humanos avaliando a ativação do sistema complemento e a produção de anticorpos específicos mostram que a resposta inata e de anticorpos são importantes para a delimitação do processo infeccioso por Cryptococcus sp, como também, a administração de anticorpos monoclonais podem induzir uma resposta eficaz na disseminação da doença. O sistema complemento contribui para a defesa do organismo contra o Cryptococcus sp de diferentes maneiras: secretando opsoninas e fatores quimiotáticos e colaborando com a ação dos anticorpos específicos, aumentando a interação entre a imunidade inata e adquirida. Os anticorpos antiglicuroxilomanana (GXM) possuem numerosas atividades biológicas: a) opsonização para fagocitose, b) ativação da via clássica do complemento resultando na deposição precoce de fragmentos de C3 no fungo, c) supressão do excesso de acúmulo de C3 pela via alternativa; d) facilitação do clareamento do GXM do soro in vivo, resultando no maior acúmulo de GXM nos tecidos ricos em células do sistema fagocítico mononuclear; e) proteção em modelos murinos da criptococose e f) facilitação de vários aspectos da imunidade celular ao Cryptococcus sp. O objetivo desse estudo foi avaliar a resposta humoral ao GXM e às proteínas da parede celular (Ag S) avaliando a atividade do sistema complemento como também a produção de anticorpos específicos em amostras séricas de adultos com e sem neurocriptococose. Foram coletadas 106 amostras de soro e divididas em 3 grupos: grupo 1- 21 indivíduos com neurocriptococose e baixa exposição a levedura, grupo 2- foi composto por 23 indivíduos saudáveis com alta exposição ao fungo e HIV negativos, granjeiros da cidade de Jumirim localizada a 164 km de São Paulo, na região de Sorocaba e, o grupo 3- 60 indivíduos saudáveis, HIV negativos e com baixa exposição ao Cryptococcus sp. Dois pacientes foram excluídos do estudo por apresentarem tumores (timona e câncer de pulmão). O sistema complemento foi avaliado por ensaio hemolítico (CH 50 e AP 50) e, a dosagem da proteína ligadora de manose (MBL) foi feita por ELISA. Os valores de CH 50 estiveram dentro da normalidade em 17/21, 13/23, 59/60 indivíduos dos grupos 1, 2 e 3 respectivamente. A média dos valores de CH 50 foi diferente significativamente entre o três grupos (P < 0,0001). O grupo 2 mostrou níveis reduzidos significantes em comparação aos dois outros grupos. Os valores de AP 50 estiveram dentro da normalidade em 11/21; 21/23 e 60/60 indivíduos dos grupos 1, 2 e 3 respectivamente. Houve diferença nos valores de AP 50 (P = 0,0005) e apenas um paciente do grupo 1 apresentou valores indetectáveis desta via. Houve diferença significante na dosagem de MBL entre os três grupos (P = 0,0277). Anticorpos IgG anti-GXM foram quantificados por ELISA e expressos por densidade óptica (DO). IgG anti GXM foi detectado em todos os grupos com diferença significante entre eles (P= 0,0127). As médias de IgG anti- GXM (DO) foram: 1.191 (0,49 a 1.217) no grupo 1, 1.572 (0,815 a 2.479) no grupo 2 e 0,965 (0,321 a 1.295) no grupo 3. Dois indivíduos assintomáticos do grupo 2 tiveram títulos de GXM detectáveis (1/256 e 1/32). Quatro pacientes com neurocriptococose faleceram (19%) e seus resultados mostravam: CH 50 normal, 2/4 tinham valores de AP 50 baixo (12 UI/mL) e indetectável; 3/4 tinham altos níveis de MBL e apenas um tinha baixa DO de IgG anti-GXM. Baseado em nosso estudo, podemos concluir que a resposta humoral (sistema complemento e anticorpos) não é suficiente para explicar a susceptibilidade a neurocriptococose, porém a alta e constante exposição ao Cryptococcus sp pode prevenir o desenvolvimento de doença, ou seja, a constante e intensa exposição ao fungo induz a produção de anticorpos que previnem a doença clínica mas não a infecção. Por outro lado fatores genéticos que determinam as concentrações de MBL podem influenciar na susceptibilidade a neurocriptococose. Os anticorpos contribuem para o clearence de GXM, entretanto as concentrações séricas não se correlacionam com resistência à doença / Cryptococcus sp is a fungal pathogen with a worldwide distribution. Although it is ubiquitous in the environment, cryptococcal disease occurs predominantly in immunocompromised hosts and can also occur in apparently immunocompetent individuals. The innate immunity is of special relevance for the antifungal reaction, as it allows an immediate reaction and recognizes a broad variety of fungal pathogens. The host immune response is a major determinant of the outcome of cryptococcal infection; however, the antibodies response is poorly understood. In addition, most of the studies are experimental and there is restricted knowledge concerning the human immune response. Complement system has soluble factors, restrictive regulator proteins and cellular receptors involved in defense mechanism. Glucuroxylomannan (GXM) monoclonal antibodies (MAbs) have numerous biological activities: a) opsonization for phagocytosis, b) activation of the classical complement pathway leading to early deposition of C3 fragments on the yeast, c) suppression overall accumulation of C3 via the alternative pathway; d) clearance facilitation of GXM from serum in vivo, leading to increased accumulation of GXM in tissues rich in mononuclear phagocyte system; e) protection in murine models of cryptococcosis and f) facilitation of various aspects of cellular immunity to Cryptococcus sp. The goal of our study was to evaluate if the antibody response to GXM and cell wall proteins regarding specific antibodies as well as complement system in sera of immunocompetent adults with and without neurocryptococcosis. The aim of our research was to evaluate classical and alternative complement system pathway, to quantify mannose-binding lectin (MBL) as well antibody response to GXM and cell wall proteins (AgS) regarding specific antibodies in sera of immunocompetent adults with and without neurocryptococcosis. One hundred and six samples were collected and classified in 3 groups: group 1- 21 individuals with neurocryptococcosis and low exposure to the yeast; group 2- was composed by 23 healthy individuals, chicken farmings from Jurumirim, a town 164 km to São Paulo, and with high exposure to Cryptoccocus spp and HIV negative. The third group included 60 healthy HIV negative individuals with presumed low exposure to Cryptococcus. Two patients were excluded by report of previous malignancies (timoma and pulmonary cancer). The complement system was evaluated by hemolytic assay and ELISA to MBL. CH 50 and AP 50 values were within the normal range in 17/21; 13/23; 59/60 patients in groups 1, 2 and 3 respectivelly. Mean CH 50 values were significantly different among the three groups (P < 0,0001). Group 2 showed significantly reduced levels in comparison with groups 1 and 3. AP 50 values were within the normal range in 11/21; 21/23; 60/60 patients in groups 1, 2 and 3 respectivelly. There was difference in the AP 50 values (P=0,0005) and one no activation of this pathway in group 1. There was significant difference in MBL among the groups (P = 0,0277). GXM antibodies IgG was measured by ELISA and expressed as optical density (OD). GXM- IgG was detected in all the groups with significant difference among them (P = 0,0127). The means of IgG anti-GXM (OD) were: 1.191 (range 0,49 to 1.217) in group 1, 1.572 (range 0,815 to 2.479) in group 2 and 0,965 (range 0,321 to 1.295) in the group 3. Two of the group 2 individuals had low GXM titers (1/256 and 1/32) and no symptoms. Four patients (4/21; 19%) with neurocryptococcosis died and the results showed: normal classical pathway activation, 2/4 had low (12 UI/mL) or undetectable alternative pathway values ; 3/4 had high MBL concentrations and only one had low OD for IgG anti-GXM. In conclusion, our results suggest that constant and high exposure to Cryptococcus sp can prevent the development of cryptococcosis, i.e. constant and intensive fungal exposition induces protective antibodies to clinical disease but not to the infection. In the other side, genetic factors which determine MBL concentrations could influence the susceptibility to neurocryptococcosis. The antibodies contribute to GXM clearance, however, the concentrations did not correlate with the resistance to the disease

Large numbers of samples often need to be prepared and analysed in surveys of organic pollutants in the environment, but while the methods commonly used in such surveys can provide abundant detail they are generally costly, time-consuming and require large amounts of resources, so there is a need for simpler techniques. The work underlying this thesis assessed the potential utility of more convenient sample preparation and bioanalytical techniques for rapidly screening various environmental matrices that could be useful complements to higher resolution methods. Initially, the utility of a simplified extraction technique followed by an enzyme-linked immunosorbent assay (ELISA) for detecting polycyclic aromatic hydrocarbons (PAHs) in authentic (i.e. unspiked) contaminated soils was explored. The results showed that there are relationships between the structure and cross-reactivity among compounds that often co-occur with target PAHs. However, their potential contribution to deviations between estimates of total PAH contents of soils obtained using ELISA and gas chromatography-mass spectrometry (GC-MS) based reference methods were limited. Instead, the cross-reactivity of target PAHs and the failure to extract all of the PAHs prior to the ELISA determinations were the main reasons for these deviations. Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were detected in food and feed matrices, as well as in authentic contaminated soils using different bioanalytical techniques – ELISA and two cell-based bioassays: CAFLUX and CALUX (chemically activated fluorescent/luciferase gene expression) assays. In addition, enhanced sample preparation techniques based on accelerated solvent extraction (ASE) were developed. ASE with integrated carbon fractionation (ASE-C) in combination with CAFLUX produced estimates of PCDD and PCDF contents in fish oil and fish meal that agreed well with results obtained using reference methods. Furthermore, results from ELISA and GC-high resolution MS analyses of extracts of PCDD- and PCDF-contaminated soil samples obtained using an adjusted ASE-C technique were strongly correlated. Finally, the thesis reports the first experiments in which the results of CAFLUX, CALUX, and ELISA determinations of PCDDs and PCDFs in extracts of authentic contaminated soil samples were evaluated and compared to those obtained using a reference method. All of the bioanalytical techniques were found to be sufficiently sensitive, selective, and accurate for use in screening in compliance with soil quality assessment criteria. Overall, the improved sample preparation and bioanalytical techniques examined proved to be useful potential complements to conventional methods, enhancing the analytical framework for PAHs, PCDDs, and PCDFs. However, further validation has to be undertaken before they are applied on a large-scale.

Thesis (MSc (Genetics))--Stellenbosch University, 2008. / South Africa is one of the top ten wine producing countries in the world. The South African wine industry contributes approximately R16.3 billion to South Africa’s annual gross domestic product with 42.8% of wine being exported. To compete with the top wine producing countries and to ensure a viable export market, South Africa needs to ensure that healthy, virus free propagation material is produced and sold. One of the viruses that need to be tested for is Grapevine fanleaf virus (GFLV). Grapevine fanleaf virus causes degeneration and malformation of berries, leaves and canes and is responsible for significant economic losses by reducing crop yields by as much as 80%, reducing the longevity of the vines and affecting fruit quality. It is widespread in the Breede River Valley of the Western Cape where the nematode vector, Xiphinema index, is prevalent. The Breede River Valley contributes approximately 30% of the total production of the local wine industry, and severe losses in this region could threaten the viticulture. The Plant Improvement Act states that all propagation material sold must be tested for GFLV by a reputable scientific technique. The technique commonly used in South Africa is the Double Antibody Sandwich - Enzyme-linked Immunosorbent Assay (DAS-ELISA) and the kits are imported from Europe at a significant cost to the South African viticulture industry. The objective of this study was to produce a reliable and sensitive diagnostic assay specific for the South African strains of GFLV. This project aimed to develop and optimize a DAS-ELISA, by using recombinant DNA technology to produce antibodies against bacterially expressed viral coat protein. Total RNA was extracted from GFLV infected grapevine material and the viral coat protein (CP) amplified. The CP was cloned into the pGex-6P-2 expression vector, fusing a Glutathione STransferase (GST) partner to the viral coat protein enhancing solubility and protein purification. Insufficient amounts of the soluble protein were expressed and purified, preventing the production of antibodies and thus the development of the DAS-ELISA. An alternative diagnostic rapid-direct-one-tube-RT-PCR assay was developed. This rapid-directone- tube-RT-PCR assay was compared to commercially available DAS-ELISA and ImmunoStrip tests (Agdia) to assess the reliability, sensitivity and specificity of the rapid-direct-one-tube-RTPCR assay. Twelve GFLV isolates from South Africa were sequenced to investigate the variability between the isolates as well as the variability between the South African isolates and GFLV sequences available in Genbank. Sequence identities between clones from different GFLV isolates from South Africa were between 86-99% and 94-99% at the nucleotide and amino acid levels, respectively. Phylogenetic analysis based on the coat protein gene sequences showed that the South African isolates form two distinct clades or sub-populations. No significant correlation was found between geographical origin and symptoms, nor between geographical origin and sequence variability or between grapevine cultivar and symptom expression. Of the 23 samples tested with all three tests, 21 tested positive with rapid-direct-one-tube-RT-PCR, 19 with the ImmunoStrips and 17 with an imported DAS-ELISA kit (Agdia). Rapid-direct-one-tube-RT-PCR was found to be the most reliable technique for GFLV detection. Although the establishment of a DAS-ELISA directed to the South African strain(s) of GFLV was not successful, an alternative PCR based diagnostic system was developed, and proved to be sensitive and reliable. RT-PCR based diagnostic assays are generally accepted to be more sensitive than DAS-ELISA, but the latter is still used as the diagnostic assay of choice for routine testing due to ease of use. This rapid-direct-one-tube-RT-PCR assay is a rapid, sensitive and reliable diagnostic test, reducing the prevalence of false negatives, contributing to a virus free viticulture industry. The rapid-direct-one-tube-RT-PCR assay is as easy to use as DAS-ELISA, faster and can be performed by semi skilled workers, thus providing all the advantages associated with DAS-ELISA.

>Magister Scientiae - MSc / Glucose oxidase (GOx) and horseradish peroxidase (HRP) are important enzymes for the development of amperometric enzyme linked immunosensors. The selectivity of each enzyme towards its analyte deepens its importance in determining the sensitivity of the resultant immunosensor. In designing immunosensors that have customized transducer surfaces, the incorporation with FAD and iron based enzymes ensures that electron kinetics remains optimal for electrochemical measurement. Various different immobilization strategies are used to produce response signals directly proportional to the concentration of analyte with minimal interferences. The combination of self-assembled monolayers and supramolecular chemistry affords stability and simplicity in immunosensor design. In this work, two electrochemical strategies for the detection of human chorionic gonadotropin(hCG) is presented. This involves the modification of a gold surface with a thiolated β-cyclodextrin epichlorohydrin polymer (βCDPSH) to form a supramolecular inclusion complex with ferrocene (Fc)-functionalised carboxymethyl cellulose polymer (CMC). Cyclic voltammetry indicated that ferrocene is in close proximity to the electrode surface due to the supramolecular complex formed with βCDPSH. Furthermore, strategy (a) for the detection of hCG used α-antihCG labelled (HRP) as reporter conjugate. Strategy (b) maintained the CMC bifunctionalised with Fc and recognition antibody for hCG hormone. However, the system was functionalised with a HRP enzyme and detection is done by using GOx reporter conjugates for in situ production of hydrogen peroxide. The reduction of H2O2 was used for the amperometric detection of hCG by applying a potential of 200 mV. The sensitivity and limit of detection of both strategies were calculated from calibration plots. For strategy (a) the LOD was found to be 3.7283 ng/mL corresponding to 33.56 mIU/mL and a sensitivity of 0.0914 nA ng-1 mL-1. The corresponding values for strategy (b) are 700 pg/mL (6.3 mIU/mL) and 0.94 nA ng-1 mL-1.

Philosophiae Doctor - PhD (Chemistry) / Tuberculosis (TB) is an airborne disease caused by Mycobacterium tuberculosis (MTB) that usually affects the lungs leading to severe coughing, fever and chest pains. It was estimated that over 9.6 million people worldwide developed TB and 1.5 million died from the infectious disease of which 12 % were co-infected with human immunodeficiency virus (HIV) in the year 2015. In 2016 the statistics increased to a total of 1.7 million people reportedly died from TB with an estimated 10.4 million new cases of TB diagnosed worldwide. The development of the efficient point-of-care systems that are ultra-sensitive, cheap and readily available is essential in order to address and control the spread of the tuberculosis (TB) disease and multidrugresistant tuberculosis.

Magister Scientiae - MSc / The toxicity of microcystin is associated with the inhibition of serine/threonine protein phosphatases 1 and 2A, which can lead to hepatocyte necrosis and haemorrhage. Analysis of microcystin is most commonly carried out using reversed-phase high performance liquid chromatographic methods (HPLC) combined with ultra-violet (UV) detection .The ability of these techniques to identify unknown microcystin in environmental samples is also restricted by the lack of standard reference materials for the toxins. Highly specific recognition molecules such as antibodies and molecularly imprinted polymers (MIPs) have been employed in the pre-concentration of trace levels of microcystin from water and show great potential for the clean-up of complex samples for subsequent analysis. New biosensor technologies are also becoming available, with sufficient sensitivity and specificity to enable rapid ‗on-site‘ screening without the need for sample processing. In this work we constructed a Protein phosphatase biosensor for detection of microcystin-LR in aqueous medium, onto polyamic acid/graphene oxide (PAA: GO) composite electrochemically synthesised in our laboratory. The composites were synthesised at three different ratios i.e. 50:50, 80:20 and 20:80 to evaluate the effect of each component in the search to produce highly conductive mediator platforms. The electrochemistries of the three different composites were evaluated using CV and SWV to study interfacial kinetics of the materials as thin films at the glassy carbon electrode. The phosphatase biosensor parameters were evaluated using CV, SWV, EIS and Uv-vis spectroscopy. The affinity binding of the microcystin-LR to protein phosphatase 2A was investigated using electrochemical impedance spectroscopy which is a highly sensitive method for measuring interfacial kinetics of biosensor systems.

Made available in DSpace on 2015-03-26T13:46:43Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1492276 bytes, checksum: 4d382ffe8ee028de0569c86987765f6b (MD5) Previous issue date: 2004-12-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study was carried out with the purpose to develop an serological diagnosis protocol of bovine cysticercosis for the ELISA test using two metacestodes antigens of Taenia crassiceps and three of Taenia solium. There were used 20 sera of experimentally infected cattle with T. saginata eggs, 60 of cattle with natural infection, diagnosed at slaughterhouses, five of cattle negative for cisticercose, reared in isolation, 55 of negative bovine in slaughterhouses and 10 of bovine with actinomicosis (n=2), actinobacilosis (n=1), fasciolosis (n=1) diagnosed at slaughterhouse and of experimentally infected cattle with Anaplasma marginale (n=3), Babesia sp. (n=2) and concomitant infection for Anaplasma marginale and Babesia bovis (n=1). There were used the total and fluid cistic antigens of T. Crassiceps metacestodes and escólex and membrane antigens of T. solium metacestodes in ELISA test, after previous characterization in polyacrylamide gel electrophoresis (PAGE) in gradient 5 to 20%. The better antigen concentration was 1 µg and the better sera and conjugated dilutions were 1:25 and 1:5.000, respectively. Although the T. solium antigens have provided the most sensibility values, the T. crassiceps antigens also showed good performance to the bovine cysticercosis diagnosis. Different control serum groups employed for the cut-off calculation had changed the ELISA test results. We can concluded that the ELISA test for antibodies detection presents deficiencies in the diagnosis of naturally infected animals that showed low sensibility (5 to 32%) for different antigens. However, for experimentally infected cattle, the sensibility was high, 75 to 90% for different antigens. The test could still be considered useful in the differentiation between the cisticercose and other diseases, due to its high specificity rates (81 to 100%). / A cisticercose bovina é uma zoonose que tem o ser humano como único hospedeiro definitivo. Além de sua importância para a Saúde Pública, esta parasitose acarreta prejuízos econômicos em matadouros, ao levar as carcaças acometidas a julgamento. Este trabalho teve como objetivo o desenvolvimento de um teste de diagnóstico sorológico da cisticercose bovina pelo teste ELISA empregando dois antígenos de larvas de Taenia crassiceps e três de Taenia solium. Foram utilizados 20 soros de bovinos infectados experimentalmente com ovos de T. saginata, 60 de bovinos com infecção natural, diagnosticados em matadouros, cinco de bovinos negativos para cisticercose, criados sob isolamento, 55 de bovinos considerados negativos em matadouros e 10 de bovinos portadores de actinomicose (n=2), actinobacilose (n=1), fasciolose (n=1) diagnosticados em matadouro e de bovinos infectados experimentalmente com Anaplasma marginale (n=3), Babesia sp. (n=2) e infecção mista por Anaplasma marginale e Babesia bovis (n=1). Foram empregados os antígenos total e vesicular de larva de Taenia crassiceps e total, de escólex e de membrana de larva de Taenia solium no teste ELISA, após prévia caracterização em eletroforese em gel de poliacrilamida (SDS-PAGE) sob gradiente 5 a 20%. Após a realização de ensaios de avaliação do desempenho do teste em duas etapas, sempre considerando o critério da amplitude da diferença entre densidades ópticas de soros-controle positivos e negativos, foram obtidos os resultados que se seguem. A concentração de 1 µg de antígeno por orifício foi a que proporcionou, na maioria das vezes, a maior diferenciação entre soros positivos e negativos com todos os cinco antígenos estudados. As diluições 1:25 de soros e 1: 5.000 de conjugado também foram as que se destacaram, à exceção do antígeno de líquido vesicular de larva de T. crassiceps, que teve melhor desempenho quando o conjugado foi diluído a 1:2.500 vezes. O leite desnatado foi a melhor substância bloqueadora dos sítios reativos remanescentes da placa. Embora os antígenos de larva de T. solium tenham proporcionado valores mais elevados de sensibilidade, os antígenos de larva de T. crassiceps também mostraram bom desempenho no diagnóstico de cisticercose bovina. A escolha de diferentes grupos de soroscontrole para o cálculo do ponto de corte interferiu de forma expressiva no desempenho do teste ELISA. Pode-se concluir que o teste ELISA para detecção de anticorpos apresenta deficiências no diagnóstico de animais destinados ao abate, em virtude de sua baixa sensibilidade (5 a 32%) para diferentes antígenos, quando se consideram soros de animais com infecção natural, geralmente discreta. No entanto, no caso de animais infectados experimentalmente, a sensibilidade se mostrou elevada, 75 a 90%, para diferentes antígenos. O teste ainda pode ser considerado útil na diferenciação entre a cisticercose e outras doenças, devido às suas elevadas taxas de especificidade (81 a 100%).

Made available in DSpace on 2015-07-22T20:49:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-27 / Uma cisteína proteinase recombinante, rLdccys1, obtida pela expressão do gene Ldccys1 de Leishmania (Leishmania) chagasi em sistema bacteriano, foi utilizada em ensaios de imunodiagnóstico por ELISA e DTH em cães de uma região endêmica de leishmaniose visceral (LV), Teresina, Piauí. A rLdccys1 também foi utilizada para a imunização de cães e a avaliação da possível proteção dos animais imunizados contra o desafio com a L. (L.) chagasi. Os ensaios por ELISA dos soros de cães com LV mostraram que a sensibilidade para a detecção de anticorpos anti-L. (L.) chagasi utilizando a rLdccys1 e os extratos de promastigotas e amastigotas de L. (L.) chagasi foi de 98%, 86% e 89%, respectivamente. A rLdccys1 não apresentou reatividade cruzada com os soros de cães com doenças comuns nas regiões endêmicas de LV, tais como erliquiose, babesiose e doença de Chagas e a especificidade dos ensaios de ELISA utilizando-se a rLdccys1 e os extratos de amastigotas e promastigotas de L. (L.) chagasi foi de 96%, 69% e 68%, respectivamente. As respostas de DTH foram avaliadas nos cães após a injeção subcutânea da rLdccys1 ou do extrato dos amastigotas de L. (L.) chagasi. Todos os cães assintomáticos apresentaram resposta de DTH positiva à rLdccys1 com a formação de nódulos em torno de 10 mm 48 horas após a injeção do antígeno, enquanto que os cães sintomáticos não apresentaram reatividade significante à rLdccys1 nos ensaios de DTH. As respostas de DTH foram mais intensas quando se utilizou a rLdccys1 comparadas às observadas com o extrato dos parasitas. A análise histológica mostrou áreas de necrose e hemorragia nos nódulos induzidos pelo extrato dos parasitas e reação granulomatosa típica, com predomínio de células mononucleares, nos cortes dos nódulos induzidos pela rLdccys1. A análise dos dados obtidos nos ensaios de ELISA e DTH realizados com a rLdccys1 e os extratos de amastigotas de L. (L.) chagasi mostrou a correlação inversa entre as respostas humoral e celular no desencadeamento da LV canina. As respostas celulares induzidas nos cães pela rLdccys1 foram avaliadas após a imunização dos animais com o antígeno recombinante juntamente com a Propionibacterium acnes. Os linfócitos de sangue periférico dos cães imunizados com a rLdccys1 + P. acnes apresentaram significantes índices de estimulação quando reestimulados in vitro com a rLdccys1 ou o extrato dos amastigotas de L. (L.) chagasi. A dosagem de citocinas nos sobrenadantes dessas culturas mostrou a secreção de níveis significantes de IFN-γ, enquanto IL-10 não foi detectada. Nos experimentos em que cães foram imunizados com a rLdccys1 + P. acnes e desafiados com a injeção intraperitoneal de 1x104 amastigotas isolados de cão infectado com a L. (L.) chagasi 3 de 4 animais sobrevieram dez semanas após o desafio, enquanto que os animais controles que receberam PBS e a P. acnes morreram em no máximo 4 e 6 semanas, respectivamente, após o desafio. Nos cães imunizados com a rLdccys1 o número de amastigotas de L. (L.) chagasi foi significantemente reduzido no baço, fígado e medula óssea comparado ao observado nos controles. A dosagem sérica de IFN-γ nos animais imunizados com a rLdccys1 mostrou a secreção significante dessa linfocina, enquanto que níveis basais de IL-10 foram detectados. Todos os cães imunizados com a rLdccys1 e desafiados pela picada das fêmeas de Lutzomyia longipalpis sobreviveram até dezesseis semanas após o desafio e os animais controles injetados com PBS e P. acnes morreram sete e nove semanas, respectivamente, após o desafio. Os cães controles apresentaram número significante de amastigotas de L. (L.) chagasi no fígado e baço, porém nos animais imunizados com a rLdccys1 nenhum parasita foi observado. No grupo imunizado com a rLdccys1 houve aumento crescente dos níveis séricos de IFN-γ durante a imunização que atingiu um pico uma semana após o desafio, enquanto que e a concentração de IL-10 foi mantida em níveis basais. Os dados do presente trabalho mostraram o potencial da rLdccys1 de L. (L.) chagasi para o diagnóstico e a imunoprofilaxia da LV canina, abrindo perspectivas para a imunização dos cães em larga escala nas regiões endêmicas de LV e a avaliação do impacto da proteção conferida nos animais imunizados na incidência da doença. / A recombinant protein, rLdccys1, produced by expression of the gene encoding a 30 kDa cysteine proteinase from Leishmania (Leishmania) chagasi, was used to detect specific antibodies in serum by enzyme-linked immunosorbent assays and to test for reactivity in delayed-type hipersensitivity (DTH) responses of dogs from an endemic region of visceral leishmaniasis (VL), Teresina, Piauí State, Brazil. The recombinant protein was also used for immunization of dogs and evaluation of its possible protective role against L. (L.) chagasi infection. The sensitivity for detection of specific antibodies to L. (L.) chagasi using rLdccys1 and lysates from L. (L.) chagasi promastigotes and amastigotes was 96%, 68%, and 69%, respectively. No cross reactivity between rLdccys1 and Chagas disease was observed, and little reactivity was found with sera from dogs with babesiosis and ehrlichiosis. The specificity of ELISA assays using rLdccys1, lysates from L. (L.) chagasi promastigotes and amastigotes was 96%, 69%, and 68%, respectively. DTH responses were determined after subcutaneous injection of rLdccys1 or L. (L.) chagasi amastigote extract and the induration area was measured at 24, 48 and 72 h after injection. All asymptomatic dogs showed a positive intradermal response to rLdccys1 (10 mm) which peaked at 48 h, whereas no significant reactivity to the recombinant antigen was found in the symptomatic group. DTH responses to rLdccys1 were higher than those induced by amastigote extract. Histological analysis of the intradermal induration showed a predominance of necrotic and hemorrhagic areas in sections from asymptomatic dogs injected with L. (L.) chagasi amastigote extract, whereas a typical granulomatous reaction mediated by mononuclear cells was observed in sections from asymptomatic animals injected with rLdccys1. Data analysis from ELISA and DTH assays with rLdccys1 and L. (L.) chagasi amastigote extracts showed that humoral and cellular responses were inversely correlated during the development of canine VL. Cellular immune responses induced by the recombinant antigen were evaluated after immunization of dogs with rLdccys1 plus Propionibacterium acnes. Peripheral blood mononuclear cells isolated from rLdccys1-immunized dogs showed significant stimulation indexes after in vitro incubation with either rLdccy1 or L. (L.) chagasi amastigote extracts. Cytokine dosages in the supernatants from lymphocyte cultures showed significant levels of IFN-γ, whereas IL-10 was not detected. Whereas 3 from 4 dogs immunized with rLdccys1 plus P. acnes and challenged by intraperitoneal injection of 1x104 L. (L.) chagasi amastigotes survived ten weeks after challenge, control dogs which received either PBS or P. acnes died after four and six weeks, respectively. The load of L. (L.) chagasi amastigotes in spleen, liver, and bone marrow from rLdccys1-immunized dogs was significantly reduced in comparison to that of non immunized controls. A significant concentration of IFN-γ and basal levels of IL-10 were detected in sera from dogs immunized with rLdccys1. All dogs immunized with rLdccys1 plus P. acnes and challenged by the bite of L. (L.) chagas infected Lutzomyia longipalpis survived until sixteen weeks after challenge, whereas control dogs injected with PBS or P. acnes died after seven and nine weeks, respectively. Control dogs showed a significant number of L. (L.) chagasi amastigotes in liver and spleen, but no parasites were found in rLdccys1- immunized dogs. During immunization with rLdccys1 there was an increase of serum levels of IFN-γ in the immunized dogs that peaked one week after challenge. In contrast, a very low concentration of IL-10 was detected in these animals. Overall, these findings indicate that L. (L.) chagasi recombinant cysteine proteinase is potentially useful for diagnosis and immunoprophylaxis of canine VL. We believe that results obtained open perspectives for immunization of dogs in the field and evaluation of the impact on the disease incidence. / TEDE / BV UNIFESP: Teses e dissertações

Submitted by Priscila Nascimento (pnascimento@icict.fiocruz.br) on 2012-11-16T11:43:38Z No. of bitstreams: 1 mauro-franca-da-silva.pdf: 1113117 bytes, checksum: 4721a993f32ab60140b4d0cf8c0f704f (MD5) / Made available in DSpace on 2012-11-16T11:43:39Z (GMT). No. of bitstreams: 1 mauro-franca-da-silva.pdf: 1113117 bytes, checksum: 4721a993f32ab60140b4d0cf8c0f704f (MD5) Previous issue date: 2007 / Fundação Oswaldo Cruz. Instituto de Tecnologia em Imunobiológicos. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil. / O vírus atenuado da febre amarela, subcepa 17DD, é utilizado por Bio-Manguinhos para a produção da vacina contra a febre amarela. Esta vacina tem sido utilizada para a imunização humana com um excelente histórico de eficácia e segurança. Entretanto, nos últimos anos, devido à ocorrência de alguns casos de eventos adversos associados ao vírus vacinal cepa 17D e subcepa 17DD, apontou-se a necessidade de desenvolvimento de uma vacina inativada. Para a implementação desta nova vacina torna-se necessário o desenvolvimento de métodos de quantificação de antígenos virais. Diferentes metodologias de quantificação podem ser utilizadas na produção de vacinas inativadas, sendo as mais comuns o teste imunoenzimático (ELISA) e o teste de dose-resposta. O presente estudo teve como objetivo o estabelecimento de um ELISA visando à detecção do antígeno do vírus da febre amarela inativado. Para este propósito, foram obtidos estoques de partículas virais da subcepa 17DD, a partir de culturas de células Vero, os quais foram purificados e quantificados por métodos bioquímicos e virológicos clássicos, respectivamente. Para o desenvolvimento do teste utilizamos diferentes anticorpos como capturana fase sólida. Os resultados obtidos para os testes utilizando o anticorpo 2D12 como captura mostraram um limite de detecção do antígeno no ELISA foi de 2,21 log 10 PFU/0,1mL e (1,55 µg/0,1mL). A partir deste valor, foi estabelecido um controle positivo contendo o vírus 17DD atenuado com título de 3,06 log10 PFU/mL e (29µg/0,1mL). Os resultados mostram, também, que o ELISA foi capaz de detectar o vírus 17DD inativado por formaldeído até a diluição 1:16 (52,9 µg/0,1mL). Baseado nos resultados obtidos acredita-se que o desenvolvimento de um teste de ELISA para detecção e quantificação do antígeno 17DD possa representar umimportante avanço tecnológico no controle da produção de uma vacina inativada contraa febre amarela. / The attenuated 17DD substrain of yellow fever virus is used in Bio-Manguinhos for yellow fever vaccine production. This vaccine has been used for human immunization with an excellent history of efficacy and safety. However, in the latest years, the occurrence of adverse events associated with 17D and 17DD substrain pointed to the necessity of developing technologies for the production of an inactivated vaccine. The implementation of this new vaccine will require methods for antigen quantification. Different methodologies of quantification can be used, being the most commonlyused the Enzyme-Linked Immunosorbent Assay (ELISA) and dose response test.The aim of this study was the establishment of an ELISA for the detection of inactivated yellow fever virus antigen. For this purpose, 17DD virus was obtained from Vero cell cultures, purified and quantified by biochemical and virological classical methods, respectively. The results showed that ELISA test using the 2D12 capture antibody presented a limit of 2,21 log10PFU/0.1mL of viral titer and (1,55 µg viral protein/0.1mL). Based on this value, a positive control was established which contained the attenuated 17DD substrain of yellow fever virus with a titer of 2,95log 10 PFU/mL and (29 µg/0.1mL). The results also showed that the ELISA was able to detect 17DD virus inactivated by formaldehyde up the dilution 1:16 (52,9 µg protein/0,1mL). The development of an ELISA test for the detection and quantification of 17DD antigen can represent an important step in the production control of the inactivated vaccine against of yellow fever.