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Hand, Nicholas. "Development of a Recombinant Attenuated Salmonella Cancer Vaccine." Thesis, The George Washington University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10635177.
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New treatments for neuroblastoma are desperately needed; high-risk neuroblastoma patients have a less than 50% five-year survival rate despite intensive treatment. The greatest impact on improving survival rates for cancer patients in recent years is the result of a number of immunotherapeutic approaches. A proportion of high-risk neuroblastoma patients undergo spontaneous regression, possibly mediated by the immune system, indicating the potential of immunotherapies targeting neuroblastoma-associated antigens. Recombinant attenuated Salmonella vaccines (RASV) are cost-effective and have shown efficacy against a number of pathogen-associated antigens and are easily adapted for use as cancer immunotherapies. Here we cloned survivin, a neuroblastoma tumor-associated antigen into RASV expression plasmids to develop 24 RASV candidate vaccines with an array of select phenotypes. While conventional recombinant attenuated Salmonella vaccines are permanently attenuated, the RASV used here are engineered with inducible in vivo attenuation and other delayed phenotypes shown to improve immune responses. Survivin expression did not impact the growth or stability of any of the RASV constructs. Six of the constructs were tested in vivo, the RASV survived in the gut lumen, and all RASV-immunized mice produced anti-Salmonella responses. Protein/adjuvant immunized mice produced humoral and cellular survivin specific immune responses; however two independent in vivo experiments showed that no survivin specific immune responses were induced in survivin-expressing RASV immunized mice. Based on the results, a number of improvements to the future development of the vaccine are suggested.
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Breau, Cathy. "Development of an oral recombinant chancroid vaccine delivered by attenuated Salmonella typhimurium SL3261." Thesis, University of Ottawa (Canada), 2009. http://hdl.handle.net/10393/28079.
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Chancroid, a sexually transmitted genital ulcer disease caused by the Gram-negative bacterium Haemophilus ducreyi, facilitates the acquisition and transmission of H1V. An effective vaccine against chancroid has yet to be developed. We hypothesize that a Salmonella vector-based vaccine, expressing H. ducreyi antigens, could confer protective immunity in the rabbit model of H. ducreyi infection. The H. ducreyi outer membrane hemoglobin receptor HgbA has been shown to be a suitable vaccine candidate. HgbA was expressed from S. typhimurium SL3261 (pnirBhgbA) but not from the control strain, S. typhimurium SL3261 (pnirB). After a single dose or three doses, at two-week intervals of the vaccine, no antibody response to HgbA was detected in the rabbit model. The vaccine administered was immunogenic and survived in vivo passage. In this small animal trial, we were unable to induce protective immunity against chancroid. We conclude that the vaccine does not confer protective immunity against chancroid.
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O’Meara, Kellie Marcella. "Evaluation of Recombinant Salmonella Expressing CD154 for Enhanced Immune Responses in Commercial Turkeys." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1246567532.
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Kremer, Courtney J. "Evaluation of Recombinant Salmonella Expressing the Flagellar Protein FliC for Enhanced Immune Responses in Commercial Turkeys." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1246568225.
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Silva, Maria Elizabeth. "Development of a Recombinant Attenuated Salmonella Vaccine System for Taenia Solium Cysticercosis in Pigs." Digital Archive @ GSU, 2010. http://digitalarchive.gsu.edu/biology_diss/81.
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Taenia solium is a cestode that has a two-hosts life cycle. The adult tapeworm causes an asymptomatic disease known as taeniasis whereas the larval stage causes a disease called cysticercosis. In humans, the most common localization for the larvae is the central nervous system where it produces the neurological disorder neurocysticerco-sis. Previous works by several research groups around the world have shown that T. so-lium is a potentially eradicable parasite. Control programs have included treatment of human and pig populations with antihelmintics in conjunction with health education and are now considering vaccination of naïve piglets. The potential of a live vector vaccine system to deliver Taenia solium Tsol18, a proven protective antigen, to prevent transmission of cysticercosis was investigated. An attenuated strain of Salmonella enterica serovar Typhimurium χ9402 was used to develop an oral delivery system. Tsol18 gene was cloned downstream from the β-lactamase signal sequence in a multicopy asd + plasmid vector pYA3620 to yield plasmid pYA3620/Tsol18 and then transformed into the vaccine strain. The recombinant atte-nuated salmonella vaccine construct was stable for 50 generations and expressed rTsol18. Immunization of mice either with one or two doses of 109 CFU of the recombi-nant vaccine strain carrying plasmid pYA3620/Tsol18 elicited specific antibody response to Salmonella self antigens and to rTsol18. Moreover, oral immunization of piglets with 1012 CFU of the vaccine construction significantly reduced the numbers of viable cysts after challenged. The development of a quantitative assay to detect specific antibodies against Tsol18 is also presented here. The Falcon assay screening test –enzyme linked immu-noabsorbant assay (FAST-ELISA) format was used to develop a quantitative antibody detection assay. We have cloned, expressed and purified rTsol18. With purified porcine IgGs we constructed a standard curve that can be used to quantify the immune re-sponse. Our Fast-ELISA was able to follow the kinetics of the immune response in vac-cinated pigs from an experimental trial. The data we present here provides the basis for a safe, affordable and easy vaccine delivery system that can be used as an adjunct in control programs.
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Łaniewski, Paweł, Chang-Ho Baek, Kenneth L. Roland, and Roy Curtiss. "Analysis of Spleen-Induced Fimbria Production in Recombinant Attenuated Salmonella enterica Serovar Typhimurium Vaccine Strains." AMER SOC MICROBIOLOGY, 2017. http://hdl.handle.net/10150/625743.
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Salmonella enterica serovar Typhimurium genome encodes 13 fimbrial operons. Most of the fimbriae encoded by these operons are not produced under laboratory conditions but are likely to be synthesized in vivo. We used an in vivo expression technology (IVET) strategy to identify four fimbrial operons, agf, saf, sti, and stc that are expressed in the spleen. When any three of these operons were deleted, the strain retained wild-type virulence. However, when all four operons were deleted, the resulting strain was completely attenuated, indicating that these four fimbriae play functionally redundant roles critical for virulence. In mice, oral doses of as low as 1 x 10(5) CFU of the strain with four fimbrial operons deleted provided 100% protection against challenge with 1 x 10(9) CFU of wild-type S. Typhimurium. We also examined the possible effect of these fimbriae on the ability of a Salmonella vaccine strain to deliver a guest antigen. We modified one of our established attenuated vaccine strains, chi 9088, to delete three fimbrial operons while the fourth operon was constitutively expressed. Each derivative was modified to express the Streptococcus pneumoniae antigen PspA. Strains that constitutively expressed saf or stc elicited a strong Th1 response with significantly greater levels of anti-PspA serum IgG and greater protective efficacy than strains carrying saf or stc deletions. The isogenic strain in which all four operons were deleted generated the lowest anti-PspA levels and did not protect against challenge with virulent S. pneumoniae. Our results indicate that these fimbriae play important roles, as yet not understood, in Salmonella virulence and immunogenicity. IMPORTANCE Salmonella enterica is the leading cause of bacterial food-borne infection in the United States. S. Typhimurium is capable of producing up to 13 distinct surface structures called fimbriae that presumably mediate its adherence to surfaces. The roles of most of these fimbriae in disease are unknown. Identifying fimbriae produced during infection will provide important insights into how these bacterial structures contribute to disease and potentially induce protective immunity to Salmonella infection. We identified four fimbriae that are produced during infection. Deletion of all four of these fimbriae results in a significant reduction in virulence. We explored ways in which the expression of these fimbriae may be exploited for use in recombinant Salmonella vaccine strains and found that production of Saf and Stc fimbriae are important for generating a strong immune response against a vectored antigen. This work provides new insight into the role of fimbriae in disease and their potential for improving the efficacy of Salmonella-based vaccines.
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Holden, James Anthony, and jamesholden@netspace net au. "Vaccination Strategies for the Prevention of Swine Dysentery." RMIT University. Applied Sciences, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20070112.122102.
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The SmpA outer membrane lipoprotein of B. hyodysenteriae has several characteristics that indicate the potential to protect against swine dysentery (SD). It localises to the outer membrane and antibodies directed against SmpA can prevent the growth of B. hyodysenteriae in vitro. There is some variation observed in the distribution and expression of the SmpA lipoprotein, suggesting that vaccination with SmpA may not provide protection against challenge with a heterologous B. hyodysenteriae strain. This study has characterised the variation at the smpA locus, and in the process has identified a novel gene, smpB. There is very low similarity between smpB and smpA, with the exception of an identical lipoprotein signal sequence. This suggests that SmpB may be translocated to the outer membrane of B. hyodysenteriae in a similar fashion to SmpA. The results described in this thesis indicate that strains of B. hyodysenteriae harbour either smpA or smpB, but not both, explaining the earlier results of Turner et al. (1991). The presumed outer membrane location of SmpB lead to further investigations into its potential to protect mice from infection with B. hyodysenteriae. Swine Dysentery is a inflammatory disease of the swine colon. Therefore it is believed that a mucosal immune response may provide increased protection against challenge. In this study, vaccination of mice with recombinant SmpB elicited high levels of serum antibodies, induced the production of Interleukin-4 producing T lymphocytes and decreased the observed histological effects after challenge with virulent B. hyodysenteriae. In efforts to increase the protected conferred by vaccination with SmpB, recombinant Salmonella typhimurium STM-1 vaccines were created to express SmpB or deliver DNA vaccines encoding SmpB. Vaccination with these recombinant Salmonella vectors did not induce a measurable SmpB specific immune response. Macrophage survival and plasmid stability studies indicated that this was due to instability of the expression plasmids in STM-1. Although SmpB will only ever protect against strains of B. hyodysenteriae harbouring smpB, these results indicate that with further research, SmpB (and SmpA) may contribute to protection from SD. Toxin production is an important aspect of the pathogenesis of many pathogenic bacteria. Vaccination with attenuated toxins is commonly used to prevent disease. In this study, the B. hyodysenteriae â-haemolysin HlyA was used to vaccinate mice to determine the protection induced after challenge. Vaccination of mice with recombinant HlyA induced significant levels of serum antibodies and lowered the observed pathological effects after challenge of vaccinated mice with virulent B. hyodysenteriae. In an attempt to increase the mucosal immune response and therefore the protection afforded after vaccination with HlyA, recombinant S. typhimurium STM-1 strains were created to express HlyA or deliver DNA vaccines encoding HlyA. Similar to the recombinant STM-1 vaccines expressing SmpB, a HlyA specific immune response was not observed by ELISA or ELISPOT analysis. Plasmid stability trials revealed that the inability to induce a detectable HlyA specific immune response by recombinant STM-1 vaccination may be due to ins tability of the plasmids. Outer membrane proteins are often important components of vaccines against bacterial and viral pathogens. Considering the variation observed in the smpA locus in this study resulting in the identification of smpB, further investigation into the distribution and conservation of outer membrane encoding genes in B. hyodysenteriae strains was undertaken. In particular, the blpAEFG, vspABCD and vspEFGH clusters were analysed for their distribution. It was demonstrated that genes that are B. hyodysenteriae specific (vspABCD and vspEFGH) displayed higher levels of polymorphism than those that are distributed amongst non-pathogenic species, such as B. innocens (which contains blpAEFG). This suggests that the variation in the vspABCD and vspEFGH clusters amongst B. hyodysenteriae strains may be a result of the exposure to the host immune system. Further investigation was undertaken by PFGE analysis and 2D-gel electrophoresis, to analyse genomic and proteomic variation at a global level. Although strains of B. hyodyse nteriae produced several different electrophoretic types (ET) upon PFGE analysis, only limited correlation between the PFGE ET, the polymorphisms in vspABCD and vspEFGH and the presence of smpA/smpB were observed. 2D-gel electrophoresis analysis of outer membrane preparations of two B. hyodysenteriae strain revealed several distinct differences in the outer membrane between B. hyodysenteriae strains. The observed differences in the proteins contained in the outer membrane of B. hyodysenteriae is important for vaccine design, as the induction of cross protection between strains of B. hyodysenteriae is essential for a effective vaccine.
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Sevil, Victoria. "Influence of oral boost immunizations with recombinant Salmonella vaccine strains on the antigen-specific CD8 T-cell induction." Diss., lmu, 2007. http://nbn-resolving.de/urn:nbn:de:bvb:19-72867.
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Franzin, Fernanda Maria 1981. "Construção e analise da imunogenicidade de uma linhagem atenuada de Salmonella enterica produtora do dominio M2 do antigeno MAEBL de Plasmodium yoelii." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/317036.
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Orientadores: Marcelo Brocchi, Fabio Trindade Maranhão CostaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: A malária é uma doença tropical causada pelo parasita Plasmodium spp e é considerada um sério problema de saúde pública. São aproximadamente 500 milhões de casos anuais e mais de um milhão de mortes, especialmente na África e Ásia. No Brasil, são 500 mil novos casos por ano, principalmente na região Amazônica. Esses elevados índices de mortalidade e morbidade são motivadores da busca por estratégias de controle e eliminação dessa doença. A vacinação é uma ferramenta promissora no controle e prevenção da malária, entretanto, uma vacina segura e efetiva ainda não está disponível, em parte devido ao complexo ciclo de vida do parasita e a expressão de diferentes antígenos em cada fase. O antígeno de membrana similar ao ligante de eritrócitos (MAEBL), é um forte candidato a ser usado no desenvolvimento de uma vacina efetiva contra a malária, uma vez que esse antígeno é expresso em diferentes períodos do ciclo de vida do parasita. Neste estudo, o domínio M2 do antígeno MAEBL de Plasmodium yoelli foi expresso em linhagens vivas atenuadas de Salmonella enterica Typhimurium (?3987, ?4550 e H683) e o uso dessas bactérias como vacina recombinante potencialmente indutora de proteção contra malária murina foi avaliado. Essas linhagens foram obtidas após construção e transdução do plasmídio pYA3137trc contendo a região m2 do gene maebl e a expressão do antígeno foi confirmada por immunoblotting. A administração oral das linhagens recombinantes a camundongos BALB/c/AnUnib resultou na colonização dos tecidos hospedeiros apenas pela linhagem H683. Essa linhagem foi então avaliada em termos de indução de resposta imune humoral contra M2 e capacidade de imunização no modelo murino. Apesar da resposta humoral contra M2 ter sido detectada in vivo, a linhagem recombinante não demonstrou proteção potencial contra a infecção por Plasmodium yoelii no modelo murino.
Abstract: Malaria is a tropical disease caused by the parasite Plasmodium spp and is considered a serious public health problem. There are about 500 million annual cases and more than one million of deaths, especially in Africa and Asia. In Brazil, there are 500.000 new cases per year, mainly in the Amazon region. Those high rates mortality motivate the search for strategies of control and elimination of this illness. The vaccination is a promising tool in the control and prevention of malaria; however, a safe and effective vaccine is not available yet, in part due to the complex life cycle of the parasite and expression of different antigens in each phase. Membrane antigen erythrocyte binding like (MAEBL) is a strong candidate to be used in the development of an effective vaccine against malaria, since this antigen is expressed in different periods of the parasite life cycle. In this work, the M2 domain of Plasmodium yoelli MAEBL antigen was expressed in attenuated strains of Salmonella enterica Typhimurium (?3987, ?4550 e H683) and the use of these bacterias as potential inductor of protection against murine malaria was evaluated. These strains were obtained by construction and transduction of the plasmid pYA3137trc carrying the m2 region of the maebl gene and the antigen expression was confirmed by immunoblotting. The oral administration of the recombinant strains to BALB/c/AnUnib mice resulted in the colonization of host tissues only for the H683 strain. This strain was further evaluated in terms of induction of humoral immune response against M2 and immunization capacity in murine model. Even though humoral response against M2 was detected in vivo, the recombinant strains did not shown protective potential against the infection of Plasmodium yoelii in murine model.
Mestrado
Genetica de Microorganismos
Mestre em Genética e Biologia Molecular
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Chin'ombe, Nyasha. "Recombinant Salmonella enterica serovar Typhimurium vaccine vector expressing green fluorescent protein as a model antigen or human immunodeficiency virus type 1 subtype C Gag." Doctoral thesis, University of Cape Town, 2007. http://hdl.handle.net/11427/2723.
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Gatsos, Xenia, and xgatsos@optusnet com au. "The development of live vectored vaccines targeting the alpha-toxin of Clostridium perfringens for the prevention of necrotic enteritis in poultry." RMIT University. Applied Sciences, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080212.142403.
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The Ñ-toxin of Clostridium perfringens is a toxin involved in numerous diseases of humans and agriculturally important animals. One of these diseases is necrotic enteritis (NE), a sporadic enteric disease which affects avian species world-wide. This study involved the inactivation of alpha-toxin (Ñ-toxin) for use as a potential vaccine candidate to combat NE in chickens, and other diseases caused by C. perfringens type A. During the course of this research a number of Ñ-toxin recombinant proteins were developed through molecular inactivation of the Ñ-toxin gene, plc. Proteins plc316 and plc204 were developed by the deletion of the first three and seven Ñ-helices of the N-terminal domain respectively. These deletions resulted in proteins which were unstable in solution, constantly aggregated into insoluble masses and elicited lower overall antibody responses when administered to mice. A third protein, plcInv3 was developed from the deletion of part of the catalytic domain of the Ñ-toxin. PlcInv3 was highly soluble and upon immunisation of mice elicited a significant antibody response which was also capable of protecting mice against a live challenge of C. perfringens. The fourth and final protein developed was plc104. The smallest of the recombinant Ñ-toxin proteins, it consisted entirely of the C-terminal domain of Ñ-toxin. Its small size did not affect its ability to induce a strong antibody response when administered to mice, the antibodies of which were also protective during a challenge with C. perfringens. STM1, an attenuated strain of S. Typhimurium was used in the development of a vectored vaccine for the expression and oral delivery of plcInv3 and plc104 within the mouse host. The proteins were expressed within STM1 from expression plasmids containing the in vivo inducible promoters PhtrA and PpagC. A measurable humoral immune response against Ñ-toxin was absent following three oral vaccinations with the vectored vaccines, although, cytokine profiling of splenocytes from vaccinated mice revealed an increase in the number of interleukin-4 (IL-4)secreting cells and the lack of interferon-gamma (IFN-×) secreting cells. This indicated the stimulation of a T-helper type 2 (TH2) immune response which also lead to partial protection against a live C. perfringens challenge. This study demonstrates the feasibility of using STM1 as a carrier for the in vivo expression of the C. perfringens Ñ-toxin recombinant proteins plcInv3 and plc104. It is the first study to express C. perfringens antigens within an attenuated strain of S. Typhimurium, STM1.The partial protection of mice immunised with these vaccines indicates there is potential for this vectored vaccine system to be used in the protection of diseases caused by the Ñ-toxin of C. perfringens.
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Silva, Adilson José da. "Vacinas recombinantes contra erisipela suína: desenvolvimento integrado de bioprocesso, da biologia molecular ao biorreator." Universidade Federal de São Carlos, 2011. https://repositorio.ufscar.br/handle/ufscar/255.
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Previous issue date: 2011-10-11Valée S.A.
Swine erysipelas is among the diseases that causes great economic losses in swine cultures worldwide. The disease is caused by the bacterium Erysipelothrix rhusiopathiae, and the surface protein SpaA is one of its main antigens. Herein, we report studies concerning the development of recombinant vaccines against swine erysipelas based on the SpaA antigen. Protein production for a subunit vaccine formulation was studied in shaken flasks and 5.0 L bioreactors. For this propose, a 1026 bp fragment of the spaA gene was cloned in Escherichia coli cells under the lac promoter control. The recombinant organism (E. coli BL21(DE3) pET28a_spaA) was cultivated in fed batch using complex medium with glycerol as carbon source. Nonconventional induction strategies were evaluated and high protein yield (198 mgprot/gDCW) and productivity values (0.4 gprot/L.h) were reached. The same antigen was cloned for expression and secretion in attenuated Salmonella typhimurium cells to obtain a live bacterial vector for the SpaA antigen. The recombinant lineage was able to express and secrete the SpaA fragment fused to the alpha-hemolysin secretion signal both in vitro and in vivo. High plasmid maintenance was observed in both conditions. The vaccinal vehicle showed to be able to colonize the Peyer patches and to invade the gut epithelial barrier in the inoculated animals. Immunization tests in murine model showed that the recombinant antigen delivered by Salmonella cells inoculated by oral route induced the production of seric IgG antibodies anti-SpaA. According to the literature, these antibodies must be able to promote pathogen opsonization in case of infection, contributing to confer a protective immunity against swine erysipelas to the vaccinated animals. In summary, this work presents contributions to development of subunit vaccines against swine erysipelas, in the form of recombinant protein formulations, or SpaA antigen delivery by attenuated S. typhimurium cells.
A erisipela suína é uma das enfermidades que causam grandes prejuízos na suinocultura em todo o mundo. A doença é causada pela bactéria Erysipelothrix rhusiopathiae, e a proteína de superfície SpaA desse microrganismo é um de seus principais antígenos. Neste trabalho, estudou-se o desenvolvimento de vacinas recombinantes contra a erisipela suína a partir do antígeno SpaA. Avaliou-se a produção de uma vacina de subunidade composta pelo antígeno recombinante, a qual foi estudada em frascos agitados e em biorretores de bancada de 5,0 L. Para isso, um fragmento de 1026 pb do gene spaA foi clonado em células de Escherichia coli sob controle do promotor lac e o organismo recombinante (E. coli BL21(DE3) pET28a_spaA) foi cultivado em batelada alimentada, utilizando-se meio complexo contendo glicerol como fonte de carbono. Estratégias não convencionais de indução foram avaliadas e altos valores de rendimento (198 mgprot/gDCW) e produtividade (0,4 gprot/L.h) da proteína recombinante foram alcançados. O mesmo antígeno foi clonado em um plasmídeo que possibilita a expressão e secreção da proteína recombinante em Salmonella typhimurium atenuada, a fim de se obter um vetor bacteriano vivo para o antígeno em questão. A linhagem recombinante foi capaz de expressar e secretar o fragmento da proteína SpaA fusionado ao sinal de secreção da alfa-hemolisina tanto in vitro quanto in vivo, apresentando alta taxa de manutenção plasmidial nas duas condições. Além disso, o veículo vacinal se mostrou capaz de colonizar as placas de Peyer e de invadir a barreira epitelial do intestino dos animais inoculados. Ensaios de imunização em modelo murino mostraram que a veiculação do antígeno pelas células de Salmonella inoculadas por via oral induziu a produção de anticorpos IgG séricos anti-SpaA, que de acordo com a literatura, devem ser capazes de promover a opsonização do patógeno em caso de infecção, contribuindo para conferir uma imunidade protetora contra a erisipela suína aos animais vacinados. Em suma, este trabalho apresenta contribuições para o desenvolvimento de vacinas de subunidade contra a erisipela suína na forma de uma vacina de proteína recombinante, ou por veiculação do antígeno SpaA por linhagens atenuadas de S. typhimurium.
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Ashby, Deborah. "Feasibility of testing recombinant oral attenuated Salmonella vaccines in rabbits." Thesis, University of Ottawa (Canada), 2002. http://hdl.handle.net/10393/6248.
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An effective vaccine against chancroid could take the place of therapeutic control programs, offering long-lasting protection without the risk of widespread drug resistance. Orally administered recombinant attenuated Salmonella strains are used as vaccine vectors to deliver heterologous, pathogen-derived antigens to intestinal mucosal associated lymphoid tissue, and to provide vaccine adjuvancy. Chancroid vaccines are tested in a temperature-dependent rabbit model of experimental H. ducreyi infection. However, testing of recombinant attenuated Salmonella strains as vaccine vectors has never been done in rabbits; it is usually done in mice. Anatomic and physiologic differences may limit this approach to the demonstration of vaccine feasibility in rabbits. A three-part study was designed to assess the feasibility of testing attenuated Salmonella vector vaccines in rabbits. The questions asked were, (1) what is the maximum tolerated oral dose and minimum immunogenic oral dose of attenuated Salmonella in rabbits, (2) can a recombinant antigen expressed in the attenuated vector be recognized by the rabbit immune system, and (3) will experimental H. ducreyi infection in rabbits after oral Salmonella vaccination function as a comparative quantitative virulence assay to permit vaccine evaluation? (Abstract shortened by UMI.)
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Pike, Lewis James. "Salmonella vaccines : the impact of antigenic location on immune responses." Thesis, University of York, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313867.
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Zheng, Songyue, and 郑嵩岳. "Comparative immunological evaluation of recombinant Salmonella typhimurium strains expressing model antigens as live oral vaccines." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B49617734.
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Despite the development of various systems to generate live recombinant Salmonella Typhimurium vaccine strains, little work has been performed to systematically evaluate and compare their relative immunogenicity. Such information would provide invaluable guidance for the future rational design of live recombinant Salmonella oral vaccines.
Here, a series of recombinant Salmonella Typhimurium strains were constructed to express either the enhanced green fluorescent protein (EGFP) or a fragment of the hemagglutinin (HA) protein from the H5N1 influenza virus, as model antigens. To investigate different delivery and expression methods, antigens were expressed from the chromosome, from high or low-copy plasmids, or encoded on a eukaryotic expression plasmid. Antigens were targeted for expression in the cytoplasm, or the outer membrane. In addition, combinations of two expression strategies were employed to evaluate the efficacy of combined delivery approaches. After investigating in vitro and in vivo antigen expression, growth and infection abilities, the immunogenicity of the constructed recombinant Salmonella strains was evaluated and compared in mice. Using soluble model antigen EGFP, my results indicated that vaccine strains with high and stable antigen expression exhibited high B cell responses, while eukaryotic expression or colonization with good construct stability is critical for T cell responses. For insoluble antigen model HA, the outer membrane strategy induced better B cell and T cell responses than cytoplasmic strategy. Most notably, the combination of two different expression strategies did not increase the immune response elicited as initially expected.
Based on the advantages, deleterious or synergistic effects of different strategies identified in this study, I conclude that different construction strategies of recombinant Salmonella vaccine strains are needed for different forms of antigens (soluble or insoluble antigens). If the antigen (such as EGFP) is soluble and easily expressed in Salmonella, a low-copy plasmid-based strategy should be employed, as it can provoke both strong B cell and T cell responses with better plasmid stability. If a T cell response is preferred, a eukaryotic plasmid, or chromosome-based, cytoplasmic-expression strategy may achieve better results. For heterologous antigens that are likely to be expressed in an insoluble form inside Salmonella (such as HA), an outer membrane-targeting approach is recommended. In addition, I found that the combination of two expression strategies did not enhance the immune response, and hence I caution the use of such an approach.published_or_final_version
Biochemistry
Doctoral
Doctor of Philosophy
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Azevedo, Fátima da Piedade de Melo. "Inserção de epitopo heterólogo em diferentes regiões de flagelina bacteriana: influência na função flagelar e imunogenicidade." Universidade de São Paulo, 1997. http://www.teses.usp.br/teses/disponiveis/46/46131/tde-09112015-150421/.
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Uma das estratégias mais promissoras para a biotecnologia de vacinas é o desenvolvimento de linhagens precisamente atenuadas, e que possam ser usadas como carregadoras de antígenos heterólogos. Mutantes de One of the most promising strategies for the biotechnology of vaccines is the development of precisely attenuated strains, which could be used as carriers of heterologous antigens. Mutants of Salmonella Typhimurium have been extensively explored to this effect, since the infection ofmice by S. Typhimurium mimics the infection of humans by S. Typhi, and the genetics of the species is extremely well known, making it easy the obtention of defined mutants with reduced pathogenicity. Mutants with auxotrofy in genes of the aromatic pathway are particularly attractive, since they need PABA and DHB to grow, and these compounds are unavailable in mammalian tissues. Flagellin, the monomer which constitutes the flagellar filament, has been used as a carrier for heterologous epitopes, inserted in a central, hypervariable region (region IV). Insertions in this region are often functional, and lead to exposition of the epitope at the filament\' s surface. The present work explored the potential of the other regions ofthe molecule for the insertion of epitopes. We inserted the same reporter sequence (MS epitope from S. pyogenes M protein) in regions with different levels of homology (III and VI), and totally conserved (VIII). We also made double insertions in regions shown to be permissive (III and IV; IV and VI). All hybrid proteins were synthesized by Salmonella, as demonstrated by immunoblots using antibody against flagellin and against the synthetic peptide. All regions, except the highly conserved region VIII, accepted the insertions without loss of motility, albeit, in some cases, motility was seriously reduced. Immunogenicity of the hydrids was evaluated by immunization with live bacteria, killed bacteria, and purified flagellin (when possible). Results obtained with the new constructs were similar to the ones published for insertions involving region IV, in the sense that antibody titers to the carrier protein were very high. A low level of antibody to the inserted peptide was also detected in all groups of animals. Our results with live immunization suggest a slightly better response to the peptide when two copies are present, but the data are not conclusive.
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Camillo, Luciana. "Efeito da imunização com vacina do antígeno recombinante de superfície SpaA de Erysipelothrix rhusiopathiae : modelo murino." Universidade Federal de São Carlos, 2015. https://repositorio.ufscar.br/handle/ufscar/7741.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
The swine erysipelas is a disease caused by the bacterium Erysipelothrix rhusiopathiae, globally distributed. The pig farming is expanding, and pork is the most consumed in the world. Large investments have been made to increase these herds, especially in the search for vaccines. The disease is currently prevented by vaccination of flocks, but the existing formulations (inactive or attenuated pathogen) can aggravate problems of arthritis in these animals. For the development of new vaccines, free of E. rhusiopathiae cells, the protein SpaA (Surface protective antigen A) appears as a major antigen in studies. We evaluate, in mice, the immune response and the efficiency of two formulations based on SpaA antigen, and compared the results obtained with a commercial vaccine prepared with inactivated cells of the pathogen. The formulations used were: a) living cells of recombinant attenuated Salmonella typhimurium - SL3261 expressing SpaA; b) SpaA purified protein and aluminum hydroxide (v/v). After immunization and challenge of the animals, we evaluated production of antibodies (ELISA) and the inflammatory cells profile systemic infection by E. rhusiopathiae. The results showed that the purified antigen can promote 50% protection (with an over-dose challenge 50xDL50) of a virulent E. rhusiopathiae. In the DL50 challenge, we analyze the cellular profile, antibody production, and interleukin dosage. The purified protein vaccine promoted negative modulation of the output inflammatory cells from bone marrow into the blood, compared to only infected group. There was a specific IgG production against rSpaA, and the most antigenic vaccine was the purified protein, compared to commercial vaccine and recombinant Salmonella vaccine. By analysis of interleukins (IL-4 and IL-12) and IgG1 and IgG2a subclasses, we found that vaccines stimulate both the Th1 response as Th2, being observed more likely to Th2 response. Thus, these data suggest that SpaA purified protein is capable of stimulating an immune response with protective character, reducing the risk of secondary impairments like those occurring with the use of inactivated vaccines to pathogens.
A erisipela suína é uma enfermidade causada pela bactéria Erysipelothrix rhusiopathiae, distribuída de forma global. A criação de suínos está em expansão, e a carne suína é a mais consumida no mundo. Grandes investimentos têm sido realizados para o aumento destes rebanhos, com destaque para a busca por vacinas. A doença é prevenida atualmente pela vacinação de parte dos rebanhos, porém as formulações existentes (patógeno inativado ou atenuado) podem agravar problemas de artrite nesses animais. Para as novas vacinas em desenvolvimento, livres das células de E. rhusiopathiae, a proteína SpaA (Surface protective antigen A) aparece como principal antígeno em estudo. Neste trabalho, avaliamos, em modelo murino, a resposta imunológica e a eficiência de duas formulações baseadas no antígeno SpaA, e comparamos os resultados obtidos com uma vacina comercial preparada com células inativadas do patógeno. As formulações usadas foram: a) células vivas de Salmonella typhimurium– SL3261 recombinante atenuada, expressando SpaA; b) proteína SpaA purificada + hidróxido de alumínio (v/v). Após imunização e desafio dos animais, foi avaliada a produção de anticorpos (método ELISA) e o perfil inflamatório frente à infecção por E. rhusiopathiae de forma sistêmica.Os resultados obtidos mostraram que o antígeno purificado foi capaz de promover 50 % de proteção (desafio com uma super-dose de 50xDL50) de uma cepa virulenta de E. rhusiopathiae. No desafio com a DL50, foi feita análise do perfil celular, da produção de anticorpos, além de dosagem de interleucinas. A vacina de proteína purificada promoveu modulação negativa da saída das células inflamatórias da medula óssea para o sangue, em relação ao grupo apenas infectado. Houve produção de IgG específicos contra rSpaA, sendo a vacina de proteína purificada mais antigênica quando comparada a vacina comercial e a de Salmonella recombinante. Pela análise de interleucinas (IL-4 e IL-12) e das subclasses IgG1 e IgG2a, observamos que as vacinas estimulam tanto a resposta Th1 quanto a Th2, sendo observada maior tendência de resposta Th2. Assim, esses dados sugerem que, apenas a proteína purificada SpaA é capaz de estimular uma resposta imune de caráter protetor, diminuindo o risco de comprometimentos secundários como os que ocorrem com a utilização de vacinas com patógenos apenas inativados.
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Monaris, Denize. "Avaliação do potencial adjuvante da flagelina FliCi de Salmonella enterica sorovar Thyphimurium no desenvolvimento de uma vacina contra leptospirose." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/87/87131/tde-22032011-164924/.
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A leptospirose é uma zoonose de importância global causada por espiroquetas patogênicas do gênero Leptospira. Foi avaliado o potencial adjuvante da flagelina FliCi de Salmonella enterica sorovar Thyphimurium na indução de resposta imunoprotetora em uma formulação vacinal acelular composta pela proteína LigAc e por seis prováveis lipoproteínas de membrana externa recombinantes de Leptospira interrogans sorovar Copenhageni como alternativa profilática. Grupos de hamsters imunizados com LigAc co-administrada com o pool das proteínas acrescidas de FliCi ou Al(OH)3 apresentaram altos títulos de anticorpos contra as proteínas recombinantes e foram protegidos do desafio letal (86-100%). Grupos imunizados com vacina comercial, bacterina ou pool+LigAc+FliCi apresentaram redução na colonização renal (0-28%). Dados sugerem aumento da expressão dos genes das citocinas de resposta Th1/Th2. Os resultados demonstram que novas formulações vacinais, compostas por proteínas recombinantes e flagelina FliCi como adjuvante, é um caminho promissor.Leptospirosis is a global zoonotic disease caused by pathogenic spirochetes of the genus Leptospira. In the present study, we evaluated the adjuvant activity of Salmonella enterica FliCi flagellin in the protective immunity induced by the LigAc and also by six other novel recombinant leptospiral outer membrane lipoproteins (OMP) of Leptospira interrogans serovar Copenhageni. Immunization of hamsters with LigAc or LigAc coadministered with OMPs cocktail, both with FliCi or Al(OH)3, induced robust antibody responses against recombinant proteins, and conferred protection after challenge (86-100%). Moreover, only groups inoculated with the commercial vaccine, bacterin or LigAc coadministered with OMPs cocktail and FliCi as adjuvant showed reduced bacterial load in kidneys (0-28%) with significant enhancement of gene expression of both Th1 and Th2 cytokines. Taken together, our data pave the way for the development of novel vaccine formulations against leptospirosis, using recombinant proteins and FliCi as adjuvant.
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Wongkuttiya, Donruedee. "Construction of DNA vaccines and recombinant salmonella vaccines against respiratory syncytial virus, and their assessment in a murine model." Thesis, University of Newcastle Upon Tyne, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366516.
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Schroeder, Juliane. "Selection of novel antigens from Leishmania spp. and design of live recombinant salmonella vaccines against experimental visceral leishmaniasis." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2011. http://dx.doi.org/10.18452/16308.
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Leishmaniosen gehören zu den tropischen Krankheiten und bedrohen geschätzte 350 Millionen Menschen in 88 Ländern weltweit. Die schwerste Form, viszerale Leishmaniose, betrifft die ärmsten Bevölkerungsschichten und ist die Ursache für circa 50 000 Todesfälle pro Jahr. Es wird angenommen, dass die Entwicklung eines Impfstoffs möglich ist, aber trotz aller Bemühungen, steht derzeit noch kein Impfstoff zur Verfügung. Im Rahmen dieser Arbeit wurde ein Impfstoff gegen viszerale Leishmaniose entwickelt und in vivo auf pre-klinischer Ebene getestet. Des Weiteren wurden rekombinante Membranvesikel konstruiert, um ein Boostreagenz zu erhalten. Die Herstellung sowohl des rekombinanten Salmonellenimpfstoffs als auch der Membranvesikel sollte, trotz des geringen Handelspreis, ökonomisch praktikabel sein, was besonders wichtig ist für Menschen in den betroffenen Entwicklungsländern. Der erste Schritt war die Auswahl neuartiger Antigenkandidaten aus einem Proteomics Datensatz, in dem beide Leishmania Lebensformen verglichen wurden. Der Schwerpunkt wurde auf abundante, hypothetische Proteine gelegt, die sowohl in Pro- als auch Amastigoten identifiziert wurden, in Leishmanienarten hochkonserviert sind aber gleichzeitig keine Sequenzhomologien zu humanen und murinen Proteinen besitzen. Diese Antigene wurden in unterschiedlicher Menge auf der Oberfläche und im Cytoplasma von S. typhimurium SL3261 und auch auf Membranvesikeln exprimiert. Impfstämme wurden selektiert in Hinsicht auf ihre bakterielle Fitness und Antigenexpression. Es konnte gezeigt werden, dass LinJ08.1140-, LinJ23.0410-exprimierende Impfstämme oder eine Mischung dieser in der Lage waren besonders anfällige BALB/c Mäuse vor L. major und wichtiger L. donovani Infektion zu schützen. Analyse der humoralen Immunantwort deutet darauf hin, dass der Impfschutz das Ergbnis einer TH1 Antwort war. Erste Schritte zur Aufklärung struktureller und funktioneller Eigenschaften von LinJ08.1140 wurden unternommen. Es wird allgemein angenommen, dass antigenspezifische CD4+ und CD8+ T-Zellen am Schutz beteiligt sind. Daher wurde für LinJ08.1140 potentielle MHC-I Epitope mit Hilfe von bioinformatischen Programmen vorhergesagt. Zusätzlich deuten Fluoreszenz-färbungen mit antigenspezifischen Antikörpern in L. major Promastigoten darauf hin, dass LinJ08.1140 eine Rolle bei der Zellteilung spielt.Leishmaniasis is a neglected tropical disease and currently an estimated 350 million people in 88 countries around the world are at risk. Its most severe form, visceral leishmaniasis, affects the poorest people in a population and causes an estimated 50 000 deaths every year. Vaccination is thought to be feasible but despite all efforts, no vaccine is yet available. Vaccines will mainly be targeted for people in developing countries such as India, thus focus has to be placed on affordability. In this thesis a vaccine against visceral leishmaniasis was designed and evaluated in vivo at pre-clinical level. Furthermore, recombinant outer membrane vesicles were developed in an attempt to create a booster reagent. Both, the recombinant salmonella vaccine and the preparation of outer membrane vesicles should be commercially viable, and can still be sold at low prices, which is crucial for people in developing countries. First, novel antigen candidates were selected using proteomics data comparing leishmania life stages. Abundant and hypothetic proteins, which have been identified in both parasite life stages and have high sequence homology throughout Leishmania species while lacking homologues in human and mouse, were selected. These antigens were differentially expressed on the surface or in the cytosol of S. typhimurium SL3261 and in the form of outer membrane vesicles. A two step procedure was developed to select optimised vaccine strains based on bacterial fitness and antigen expression. Selected salmonella strains expressing LinJ08.1140, LinJ23.0410 or an admixture of these strains are shown to protect susceptible BALB/c mice by reducing visceralisation of L. major and more importantly L. donovani infections. Analysis of vaccine specific antibody responses suggests that protection resulted from induction of a TH1 response. First steps were undertaken towards resolving functional and structural properties of the most protective antigen LinJ08.1140. Putative MHC-I epitopes of antigen LinJ08.1140 were predicted using bioinformatics since antigen-specific CD4+ and CD8+ T cells are believed to be required. In addition, immunofluorescent staining of LinJ08.1140 in L. major promastigotes suggested a functional role for this antigen in parasite cell division, since especially dividing cells emmited a strong fluorescence signal.
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Diniz, Patricia Placona. "Estudo do potencial vacinal de proteínas de Schistosoma mansoni utilizando salmonelas atenuadas recombinantes como veículo para apresentação de antígenos ao hospedeiro." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/87/87131/tde-29042010-090416/.
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A Esquistossomose é uma das mais importantes doenças endêmicas do mundo, com mais de 200 milhões de pessoas infectadas em 76 países. É estimado que mais de 600 milhões de pessoas estejam em áreas endêmicas. Em 2003 dados do transcriptoma do Schistosoma mansoni foram disponibilizados. As informações de proteínas codificadas permitiram a análise de suas funções, e auxiliaram na procura de novos candidatos vacinais. A análise do transcriptoma permitiu a identificação de três famílias de proteínas homólogas à dineína de cadeia leve (DLC) de mamíferos. Uma delas é a família L8, com ao menos 18 membros, com proteínas em torno de 10 kDa. Essas proteínas são expressas em diferentes estágios do ciclo de vida do Schistosoma mansoni. Duas DLCs foram reconhecidas no tegumento de S. japonicum, sugerindo que elas são expostas ao sistema imune do hospedeiro. Salmonelas atenuadas como vacinas vivas têm sido descritas como bons veículos para apresentação de antígenos heterólogos. No nosso laboratório uma importante ferramenta tem sido desenvolvida para auxiliar o uso de salmonelas como vacinas vivas recombinantes, foi desenvolvido um vetor plasmididal baseado no regulon soxRS para controlar a expressão de genes heterólogos in vivo. Este sistema de expressão promove a expressão de proteínas recombinantes sob condições de estresse oxidativo, como aquele imposto ao microorganismo dentro do macrófago. Para investigar o potencial vacinal das DLCs, três genes foram selecionados para serem clonados e expressos em E. coli e em salmonelas atenuadas. A antigenicidade e imunogenicidade desses parálogos foram testadas em camundongos depois de serem imunizados com proteínas purificadas ou com salmonelas recombinantes. As DLCs mostraram ser bastante imunogênicas, aumentando os título de IgG. A proteína DLC1 também aumentou os níveis de IgE no soro dos animais, fato que poderia estar relacionado com reações alérgicas observadas em populações infetadas. Altos níveis de IgE também podem ser relacionados com uma marca de resistência existente em pessoas que vivem em áreas endêmicas. Depois de imunizados os animais foram desafiados com cercárias para investigar possível proteção. Foi observado que a imunização com proteínas purificadas resultou em aproximadamente 40% de diminuição da carga parasitária. A análise dos granulomas hepáticos com 45 dias depois da infecção indicou uma significativa redução, maior que 70% das áreas dos granulomas, sgerindo que a imunização com as DLCs promove uma importante interferência na formação dos granulomas hepáticos. Por outro lado, nossos estudos com salmonelas atenuadas recombinantes, carregando as DLCs, mostraram que foram ineficientes na apresentação dos antígenos ao sistema imune. Relacionando os resultados de diminuição de carga parasitária e das áreas dos granulomas depois da imunização com as DLCs purificadas sugere-se que essas proteínas podem ser consideradas como interessantes candidatos vacinais, uma vez que elas afetam as mais importantes causas da patologia da esquistossomose.Schistosomiasis is one of the most important endemic diseases in the world, with more than 200 million people infected in 76 countries. It is estimated that more than 600 million people live in endemic areas. In 2003 extensive data from the transcriptome of Schsitosoma mansoni was made available. The information on the encoded proteins allowed the analysis of protein function and improved the search for vaccine candidates. The analysis of the transcriptome allowed the identification of three families of proteins homologs to the mammalian dynein light chain (DLC). One of these was the L8 family, with at least 18 members, all proteins with around 10 kDa. These proteins were found to be expressed in the different stages of the S. mansoni life cycle. Two DLCs were recognized in the tegument of S. japonicum, suggesting that they are exposed to the host immune system. Attenuated salmonellas, as live vaccines, have been described as good vehicles for presentation of heterologous antigens. At our laboratory an important tool has been developed to improve the use of salmonellas as live recombinant vaccines, a plasmidial vector based on the soxRS regulon to control the expression of heterologous genes in vivo. This expression system promotes the expression of recombinant proteins under conditions of oxidative stress, such as that imposed to the microorganism in the macrophage environment. To investigate the vaccine potential of DLCs, three genes were selected to be cloned and expressed in E. coli and in attenuated salmonellas. Antigenicity and immunogenicity of these paralogous were tested in mice after immunization with purified proteins or with the recombinant salmonellas. The DLCs were proven to be very immunogenic, increasing the IgG titers. DLC1 also increased the IgE levels in the sera of animals, what could be related to allergenic reactions observed in infected population. High level of IgE can also be related to the resistance mark of people living in endemic areas. After immunization, the animals were challenged with cercarias to investigate the protective profile. It was observed that immunization with purified proteins resulted in approximately 40% decreasing in the worm burden. The analysis of the hepatic granulomas 45 days after infection indicated a significant, up to 70 %, reduction of the granuloma areas, suggesting that immunization with DLCs promotes important interference in the hepatic granuloma formation. On the other hand, our studies with the attenuated recombinant salmonellas, carrying DLCs, showed no effective antigen presentation to the mice immune system. Taking together, the results of decreasing the worm burden and the granuloma size after immunization with purified DLCs suggest that these proteins could be considered as interesting vaccine candidates, affecting the main causes of the pathology of schistosomiasis.
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Schroeder, Juliane [Verfasser], R. [Akademischer Betreuer] Lucius, Tamás [Akademischer Betreuer] Laskay, and Maurice [Akademischer Betreuer] Gallagher. "Selection of novel antigens from Leishmania spp. and design of live recombinant salmonella vaccines against experimental visceral leishmaniasis / Juliane Schroeder. Gutachter: R. Lucius ; Tamás Laskay ; Maurice Gallagher." Berlin : Humboldt Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2011. http://d-nb.info/1015046452/34.
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Nakajima, Erika. "Investigação de proteínas candidatas vacinais contra leptospirose. Apresentação de antígenos na forma de proteínas recombinantes purificadas ou como vacinas vivas em salmonelas atenuadas." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/87/87131/tde-02032011-173909/.
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A leptospirose é uma doença endêmica causada por Leptospiras. O genoma da Leptospira interrogans sorovar Copenhageni foi analisado para seleção de potenciais antígenos vacinais. Oito genes foram selecionados e clonados para expressão e purificação dos antígenos. A salmonela SL3261 foi usada como carregadora dos genes de leptospira em vetor pAEsox para expressão das proteínas in vivo. As salmonelas recombinantes induziram resposta imune quando administradas em camundongos por via intraperitoneal. Hamsters foram imunizados com as salmonelas, observando-se que a SLLIC10191 induziu proteção parcial no desafio com L. interrogans sorovar Pomona. Vetores híbridos foram construídos para expressão simultânea de dois antígenos em salmonelas in vivo. Observamos indução de anticorpos específicos, porém, os ensaios de desafio não foram conclusivos. Vários parâmetros do desafio com sorovar Copenhageni foram estudados, como contagem das bactérias e ajuste de dose, variação de virulência por passagens em cultivo e interferência da idade dos animais.Leptospirosis is an endemic disease caused by Leptospira. The genome of Leptospira interrogans serovar Copenhageni was analyzed for screening potential vaccine antigens. Eight genes were selected and cloned for expression and purification. Salmonella SL3261 was used as carrier of the genes of leptospira in pAEsox vector for in vivo proteins expression of proteins in vivo. Recombinant Salmonella induced immune response when administered intraperitoneally in mice intraperitoneally. Hamsters were immunized with salmonella, resulting we observed that the SLLIC10191 induced partial protection against on challenge with L. interrogans serovar Pomona. Hybrid vectors were constructed for expression of two antigens simultaneously by salmonella in vivo. We observed induction of specific antibodies, however, the challenge tests were not conclusive. Several parameters of the challenge assay with serovar Copenhageni were studied, such as the counting of bacteria count and dose adjustment, changes in virulence by passages in culture and interference backgroundof from the age of animals.
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Sevil, Domènech Victòria [Verfasser]. "Influence of oral boost immunizations with recombinant Salmonella vaccine strains on the antigen-specific CD8 T-cell induction / vorgelegt von Victòria Sevil Domènech." 2007. http://d-nb.info/985990163/34.
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"Effects of Cyclic Adenosine Monophosphate Independent Cyclic Adenosine Monophosphate Receptor Protein in Recombinant Attenuated Salmonella Vaccines." Master's thesis, 2012. http://hdl.handle.net/2286/R.I.15223.
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abstract: Salmonella enterica is a gastrointestinal (GI) pathogen that can cause systemic diseases. It invades the host through the GI tract and can induce powerful immune responses in addition to disease. Thus, it is considered as a promising candidate to use as oral live vaccine vectors. Scientists have been making great efforts to get a properly attenuated Salmonella vaccine strain for a long time, but could not achieve a balance between attenuation and immunogenicity. So the regulated delayed attenuation/lysis Salmonella vaccine vectors were proposed as a design to seek this balance. The research work is progressing steadily, but more improvements need to be made. As one of the possible improvements, the cyclic adenosine monophosphate (cAMP) -independent cAMP receptor protein (Crp*) is expected to protect the Crp-dependent crucial regulator, araC PBAD, in these vaccine designs from interference by glucose, which decreases synthesis of cAMP, and enhance the colonizing ability by and immunogenicity of the vaccine strains. In this study, the cAMP-independent crp gene mutation, crp-70, with or without araC PBAD promoter cassette, was introduced into existing Salmonella vaccine strains. Then the plasmid stability, growth rate, resistance to catabolite repression, colonizing ability, immunogenicity and protection to challenge of these new strains were compared with wild-type crp or araC PBAD crp strains using western blots, enzyme-linked immunosorbent assays (ELISA) and animal studies, so as to evaluate the effects of the crp-70 mutation on the vaccine strains. The performances of the crp-70 strains in some aspects were closed to or even exceeded the crp+ strains, but generally they did not exhibit the expected advantages compared to their wild-type parents. Crp-70 rescued the expression of araC PBAD fur from catabolite repression. The strain harboring araC PBAD crp-70 was severely affected by its slow growth, and its colonizing ability and immunogenicity was much weaker than the other strains. The Pcrp crp-70 strain showed relatively good ability in colonization and immune stimulation. Both the araC PBAD crp-70 and the Pcrp crp-70 strains could provide certain levels of protection against the challenge with virulent pneumococci, which were a little lower than for the crp+ strains.Dissertation/Thesis
M.S. Biology 2012
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Saron, Wilfried. "Expression chez les plantes de protéines recombinantes pour des procédures vaccinales : cas de l'Arterivirus porcin et de la flagelline de Salmonella typhimurium." Thèse, 2012. http://www.archipel.uqam.ca/4912/1/D2333.pdf.
Full textAbstract:
Ce projet avait pour but la production de protéines recombinantes pour des procédures vaccinales dans un système végétal. Les protéines choisies ont été d'une part, deux protéines virales d'un Arterivirus, le virus du syndrome reproducteur et respiratoire porcin (PRRSV), les protéines GP5 et M, et d'autre part une protéine du flagelle, la flagelline ou FljB de Salmonella typhimurium. Le PRRSV est responsable de pertes économiques majeures dans l'industrie porcine mondiale et l'efficacité des vaccins actuels contre ce virus est limitée. La protéine M a été choisie pour sa propriété à former un hétérodimère avec la protéine GP5 qui augmente la réponse immunitaire. La glycoprotéine GP5, quant à elle, possède deux épitopes dans sa région N-terminale dont un joue un rôle majeur puisqu' il est capable de stimuler la production d'anticorps neutralisants nécessaires à la clairance du virus. Enfin FljB, qui est une protéine bien conservée chez les bactéries Gram négatives, a été retenue pour ses propriétés adjuvantes intéressantes de par sa capacité à se lier au récepteur 5 de type toll (TLR5) et à induire des réponses immunitaires systémiques et mucosales. Les hypothèses pour cette étude étaient que la production d'une protéine recombinante M::GP5 intégrant trois mutations (M::GP5mut) à des sites stratégiques de celle-ci induirait une meilleure réponse immunitaire que la protéine GP5 sauvage ; que l'administration par voie orale de plante produisant la protéine M::GP5mut induirait une immunité protectrice contre le PRRSV ; que les propriétés adjuvantes de FljB produite chez Nicotiana benthamiana devraient être comparables à celles de FljB recombinante produite chez E. coli. Pour répondre à ces questions, un système transitoire d'expression chez N. benthamiana a été choisi. Il a l'avantage de pouvoir produire des protéines rapidement et à des niveaux élevés. L'immunogénicité de la protéine M::GP5mut, et les propriétés adjuvantes de la flagelline ont été testées dans un système murin. Dans le cas de la flagelline, l'ovalbumine (OVA) a été choisie comme immunogène. Peu de résultats ont été obtenus dans le cadre du projet des protéines du PRRSV du fait de l'absence de production de celles-ci à un niveau détectable bien que la présence des ARNm ait été confirmée. En revanche, pour FljB, il a été montré que l'administration par voie orale de celle-ci induisait une réponse immunitaire contre l'OVA d'une intensité égale à celle produite par l'administration du mélange OVA avec de la FljB recombinante produite par E. coli et supérieure à celle de l'OVA administrée seule. De plus, FljB recombinante produite dans N. benthamiana a permis d'obtenir une réponse plus précoce qu'avec l'utilisation de FljB recombinante produite chez E. coli. En conclusion, il a pu être montré grâce à FljB que le système de production utilisé était efficace et que FljB est un bon adjuvant qui conserve ses propriétés quand elle est produite chez N. benthamiana.
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MOTS-CLÉS DE L’AUTEUR : PRRSV, FljB, expression transitoire, adjuvant, réponse immunitaire, Nicotiana benthamiana