Streptococcus pneumoniae é uma bactéria encapsulada causadora de doenças infecciosas como pneumonia, bacteremia e meningite, infecções essas que estão entre as principais causas de morte entre crianças, idosos e imunodeprimidos, indivíduos que constituem o grupo de risco para tais infecções. A vacinação tem sido a mais eficaz forma de conter tais infecções. A vantagem das vacinas conjugadas em comparação às polissacarídicas é a capacidade de indução de uma resposta imune T-dependente o que garante proteção mesmo ao grupo de risco para infecções por S. pneumonia. A proposta do projeto foi estabelecer um protocolo para obtenção de um conjugado constituído pelo polissacarídeo capsular de S. pneumonia sorotipo 1 (PS1) e pela proteína de superfície pneumocócica A (PspA). A síntese do conjugado empregou uma metodologia inédita para o sorotipo 1. A avaliação da resposta imune humoral induzida pelo conjugado mostrou a indução de IgG anti-PS1 gerada pelas imunizações com o conjugado PS1-PspA. / Streptococcus pneumoniae is an encapsulated bacteria causing infectious diseases such as pneumonia, bacteremia and meningitis, these infections are among the leading causes of death among children, elderly and immunocompromised, who constituting individuals of risk group. The vaccination has been the more effective form to counter these infection. The advantage of conjugated vaccines compared to vaccines polysaccharide, is the ability to induce a T-dependent immune response which provides protection even at risk groups for infection by S. pneumoniae. The project proposal was establish a protocol for obtaining a conjugate consisting of the capsular polysaccharide of S. pneumoniae serotype 1 (PS1) and the pneumococcal surface protein A (PspA). The synthesis of conjugate employed a new methodology for serotype 1. The evaluation of humoral immune response induced by the conjugate showed anti-PS1 IgG induction generated by immunization with the PS1-PspA.

Malaria, caused by the Plasmodium parasite and transmitted by mosquitoes, kills almost half a million people each year. Drug resistance in both the parasite and its vector make preventative measures increasingly important, and a fully protective vaccine is absolutely necessary to eradicate the disease. However, genetic diversity of the parasite makes vaccine development difficult. One of the best vaccine candidates is MSP2, a surface protein present during the blood stage of P. falciparum infection. Antibodies, which are important for natural immunity, have been shown to bind MSP2 and prevent parasite infection of blood cells. The purpose of this study was to analyze MSP2 sequence diversity in a cohort of patients infected while traveling or living in sub-Saharan Africa, and to investigate patient antibody responses to MSP2 variants infecting other individuals. Parasite isolates from our cohort were made up of 47% 3D7 alleles and 53% FC27 alleles. Protein sequences showed similar levels of conservation within allelic families, and blocks of conserved amino acids between different variants suggest there may be epitopes that can induce antibody production targeting multiple variants. Antibody reactivity tests suggest the variable region of MSP2 is important for antibody binding to variants of the same allelic type, while the conserved region is important for reactivity to different allelic types. This thesis gives evidence to the importance of including epitopes from conserved and variable regions of both MSP2 allelic families in order to induce strain-transcending immunity against P. falciparum malaria. / A genomic surveillance platform for indel-rich genes from Plasmodium spp. using long-read amplicon sequencing

Diversas proteínas de superfície de merozoítas (MSPs) de Plasmodium têm sido consideradas candidatas a compor uma vacina contra a malária. Nos últimos anos estudamos diversos aspectos da resposta imune naturalmente adquirida contra proteínas recombinantes baseadas nas MSPs de P. vivax. Estes estudos demonstraram que estas proteínas recombinantes mantêm suas funções imunológicas, podendo servir como base para a caracterização de suas estruturas tridimensionais. Com o objetivo de obter informações estruturais sobre as MSPs de P. vivax, 10 proteínas recombinantes, correspondentes à região C-terminal da MSP-1 (MSP119), e diferentes regiões da MSP-3α e MSP-3β foram expressas em Escherichia coli. Os dados estruturais da MSP119 foram obtidos por modelagem molecular com base nas coordenadas cristalográficas da MSP19 de P. cynomolgi. Por outro lado, existem poucas informações estruturais sobre as proteínas da família MSP-3 de Plasmodium. A análise da estrutura primária dessas proteínas indica que elas apresentam um domínio central rico em alaninas que estão organizadas como motivos \"heptads\". Esse tipo de estrutura primária favorece a formação de estruturas do tipo α-hélices e \"coiled-coil\" (CC). No presente estudo, a composição da estrutura secundária de cada proteína recombinante foi caracterizada preliminarmente por ensaio de Dicroísmo Circular, realizado na região do UV distante. Com base nos resultados obtidos, selecionamos duas proteínas recombinantes baseadas na região C-terminal da MSP-3α (CC4 e CC5) para análises biofísicas mais detalhadas. Inicialmente, demonstramos por espectrometria de massa que ambas as proteínas têm massa molecular esperada. Entretanto, os dados obtidos por cromatografia em gel filtração sugeriram que essas proteínas formam oligômeros. No caso específico da proteína CC5, estes dados foram confirmados por ultracentrifugação analítica que indicou a formação de tetrâmeros elongados, corroborando com a formação de estrutura do tipo \"coiled-coil\". Como o papel biológico dessas proteínas não é conhecido, os dados estruturais obtidos neste estudo podem servir como base para o entendimento da função dessas proteínas. Na segunda parte deste projeto, selecionamos cinco proteínas recombinantes para estudos comparativos de reconhecimento por anticorpos IgG de indivíduos procedentes de áreas endêmicas de malária vivax. Tais estudos confirmaram dados prévios que as MSPs são imunogênicas em infecções naturais. Em conjunto, nossos resultados sugerem que, assim como a MSP119, proteínas recombinantes baseadas na MSP-3a e MSP-313 podem ser exploradas em futuros estudos de indução de imunidade protetora contra a malária vivax em primatas não humanos. / Several merozoite surface proteins (MSPs) of Plasmodium have been considered candidates to compose a vaccine against malaria. In the last years, we have studied severaI aspects of the natural/y acquired immune response against recombinant proteins based on MSPs of P. vivax. These studies demonstrated that the recombinant proteins maintain their immunological functions and could be used for the characterization of their three-dimensional structure. To gain structural information on the MSPs of P. vivax, 10 recombinant proteins corresponding to the C-terminal region of MSP-1 (MSP119) and to different regions of the MSP-3α and MSP-3β were expressed in Escherichia coli. The structural data of the MSP119 were obtained by molecular modeling based on the crystallographic coordinates of the P. cynomolgi MSP119. On the other hand, there is limited structural information available for MSP-3 family of Plasmodium. The analysis of the primary structure of these proteins indicates that they present a central alanine-rich domain organized as heptads repeats. This type of primary structure favors the formation of α-helices and coiled-coil (CC) structures. In the present study, the composition of the secondary structure of each recombinant protein was characterized preliminarily by circular dichroism monitored in the far-UV region. On the basis of the obtained results, we selected two recombinant proteins based on C-terminal region of the MSP-3α (CC4 and CC5) for detailed biophysical analyses. Initially, we demonstrated that the monomer mass assigned for the two recombinant proteins corresponded exactly to those predicted from the primary sequence. However, during size exclusion chromatography, the proteins eluted at volumes corresponding to molecular weights that were much larger than their monomeric masses, suggesting that both proteins are oligomeric molecules. Interestingly, analytical ultracentrifugation experiments showed that the CC5 oligomers are elongated molecules. As the function of these proteins is not known, the structural data obtained in this study can be used to understand the function of these proteins. In the second part of this study, we selected five recombinant proteins for comparative recognition by IgG antibodies of the individuais from endemic areas of malaria vivax. These studies confirmed previous data that the MSPs are imunogenic in natural infections. Together, our results suggest that, as well as the MSP119, that recombinant proteins based on the MSP-3α and MSP-3β can be explored in future studies for the induction of protective immunity against malaria vivax.

Diversas proteínas de superfície de merozoítas (MSPs) de Plasmodium têm sido consideradas candidatas a compor uma vacina contra a malária. Nos últimos anos estudamos diversos aspectos da resposta imune naturalmente adquirida contra proteínas recombinantes baseadas nas MSPs de P. vivax. Estes estudos demonstraram que estas proteínas recombinantes mantêm suas funções imunológicas, podendo servir como base para a caracterização de suas estruturas tridimensionais. Com o objetivo de obter informações estruturais sobre as MSPs de P. vivax, 10 proteínas recombinantes, correspondentes à região C-terminal da MSP-1 (MSP119), e diferentes regiões da MSP-3α e MSP-3β foram expressas em Escherichia coli. Os dados estruturais da MSP119 foram obtidos por modelagem molecular com base nas coordenadas cristalográficas da MSP19 de P. cynomolgi. Por outro lado, existem poucas informações estruturais sobre as proteínas da família MSP-3 de Plasmodium. A análise da estrutura primária dessas proteínas indica que elas apresentam um domínio central rico em alaninas que estão organizadas como motivos \"heptads\". Esse tipo de estrutura primária favorece a formação de estruturas do tipo α-hélices e \"coiled-coil\" (CC). No presente estudo, a composição da estrutura secundária de cada proteína recombinante foi caracterizada preliminarmente por ensaio de Dicroísmo Circular, realizado na região do UV distante. Com base nos resultados obtidos, selecionamos duas proteínas recombinantes baseadas na região C-terminal da MSP-3α (CC4 e CC5) para análises biofísicas mais detalhadas. Inicialmente, demonstramos por espectrometria de massa que ambas as proteínas têm massa molecular esperada. Entretanto, os dados obtidos por cromatografia em gel filtração sugeriram que essas proteínas formam oligômeros. No caso específico da proteína CC5, estes dados foram confirmados por ultracentrifugação analítica que indicou a formação de tetrâmeros elongados, corroborando com a formação de estrutura do tipo \"coiled-coil\". Como o papel biológico dessas proteínas não é conhecido, os dados estruturais obtidos neste estudo podem servir como base para o entendimento da função dessas proteínas. Na segunda parte deste projeto, selecionamos cinco proteínas recombinantes para estudos comparativos de reconhecimento por anticorpos IgG de indivíduos procedentes de áreas endêmicas de malária vivax. Tais estudos confirmaram dados prévios que as MSPs são imunogênicas em infecções naturais. Em conjunto, nossos resultados sugerem que, assim como a MSP119, proteínas recombinantes baseadas na MSP-3a e MSP-313 podem ser exploradas em futuros estudos de indução de imunidade protetora contra a malária vivax em primatas não humanos. / Several merozoite surface proteins (MSPs) of Plasmodium have been considered candidates to compose a vaccine against malaria. In the last years, we have studied severaI aspects of the natural/y acquired immune response against recombinant proteins based on MSPs of P. vivax. These studies demonstrated that the recombinant proteins maintain their immunological functions and could be used for the characterization of their three-dimensional structure. To gain structural information on the MSPs of P. vivax, 10 recombinant proteins corresponding to the C-terminal region of MSP-1 (MSP119) and to different regions of the MSP-3α and MSP-3β were expressed in Escherichia coli. The structural data of the MSP119 were obtained by molecular modeling based on the crystallographic coordinates of the P. cynomolgi MSP119. On the other hand, there is limited structural information available for MSP-3 family of Plasmodium. The analysis of the primary structure of these proteins indicates that they present a central alanine-rich domain organized as heptads repeats. This type of primary structure favors the formation of α-helices and coiled-coil (CC) structures. In the present study, the composition of the secondary structure of each recombinant protein was characterized preliminarily by circular dichroism monitored in the far-UV region. On the basis of the obtained results, we selected two recombinant proteins based on C-terminal region of the MSP-3α (CC4 and CC5) for detailed biophysical analyses. Initially, we demonstrated that the monomer mass assigned for the two recombinant proteins corresponded exactly to those predicted from the primary sequence. However, during size exclusion chromatography, the proteins eluted at volumes corresponding to molecular weights that were much larger than their monomeric masses, suggesting that both proteins are oligomeric molecules. Interestingly, analytical ultracentrifugation experiments showed that the CC5 oligomers are elongated molecules. As the function of these proteins is not known, the structural data obtained in this study can be used to understand the function of these proteins. In the second part of this study, we selected five recombinant proteins for comparative recognition by IgG antibodies of the individuais from endemic areas of malaria vivax. These studies confirmed previous data that the MSPs are imunogenic in natural infections. Together, our results suggest that, as well as the MSP119, that recombinant proteins based on the MSP-3α and MSP-3β can be explored in future studies for the induction of protective immunity against malaria vivax.

by Ng Wang Kit. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 131-139). / Abstracts in English and Chinese. / Acknowledgements --- p.iii / Abstract --- p.v / List of Tables --- p.ix / List of Figures --- p.x / List of Abbreviations --- p.xiii / Table of Contents --- p.xv / Chapter Chapter 1: --- General Introduction --- p.1 / Chapter Chapter 2: --- Literature Review --- p.3 / Chapter 2.1 --- Malaria --- p.3 / Chapter 2.1.1 --- Global picture --- p.3 / Chapter 2.1.2 --- Malaria mechanics --- p.4 / Chapter 2.1.3 --- Life cycle of malaria parasite --- p.4 / Chapter 2.2 --- Treatment of malaria ´ؤ malaria drugs --- p.5 / Chapter 2.2.1 --- Antimalarial drugs --- p.5 / Chapter 2.2.2 --- Drug resistance --- p.6 / Chapter 2.3 --- Treatment of malaria - malarial vaccines --- p.7 / Chapter 2.3.1 --- Malarial vaccine developments --- p.7 / Chapter 2.3.2 --- Transmission blocking vaccines --- p.7 / Chapter 2.3.3 --- Pre-erythrocytic vaccines --- p.9 / Chapter 2.3.4 --- Blood stage vaccines --- p.10 / Chapter 2.4 --- The major merozoite protein - gpl95 --- p.11 / Chapter 2.5 --- Plants as bioreactors --- p.12 / Chapter 2.5.1 --- Products of transgenic plants --- p.13 / Chapter 2.6 --- Transgenic plants for production of subunit vaccines --- p.14 / Chapter 2.6.1 --- Norwalk virus capsid protein production --- p.15 / Chapter 2.6.2 --- Hepatitis B surface antigen production --- p.15 / Chapter 2.7 --- Tobacco and Arabidopsis as model plants --- p.16 / Chapter 2.7.1 --- Arabidopsis --- p.16 / Chapter 2.7.2 --- Tobacco --- p.17 / Chapter 2.8 --- Transformation methods --- p.17 / Chapter 2.8.1 --- Direct DNA uptake --- p.17 / Chapter 2.8.1.1 --- Plant protoplast transformation --- p.17 / Chapter 2.8.1.2 --- Biolistic transformation --- p.18 / Chapter 2.8.2 --- Agrobacterium-mediated transformation --- p.18 / Chapter 2.8.2.1 --- Leaf-disc technique --- p.18 / Chapter 2.8.2.2 --- In planta transformation --- p.19 / Chapter 2.9 --- Phaseolin --- p.20 / Chapter 2.10 --- Detection and purification of recombinant products - Histidine tag --- p.21 / Chapter 2.11 --- Aims of study and hypotheses --- p.22 / Chapter Chapter 3: --- Materials and Methods --- p.24 / Chapter 3.1 --- Introduction --- p.24 / Chapter 3.2 --- Chemicals --- p.24 / Chapter 3.3 --- Expression in tobacco system --- p.24 / Chapter 3.3.1 --- Plant materials --- p.24 / Chapter 3.3.2 --- Bacterial strains --- p.25 / Chapter 3.3.3 --- Chimeric gene construction for tobacco transformation --- p.25 / Chapter 3.3.3.1 --- The cloning of pTZPhasp/flgp42-His/Phast (F1) --- p.26 / Chapter 3.3.3.2 --- The cloning of pBKPhasp-sp/flgp42-His/Phast (P9) --- p.30 / Chapter 3.3.3.3 --- The cloning of pHM2Ubip/flgp42-His/Nost (C2) --- p.30 / Chapter 3.3.4 --- Confirmation of sequence fidelity of chimeric gene by DNA sequencing --- p.33 / Chapter 3.3.5 --- Cloning of chimeric gene into binary vector --- p.34 / Chapter 3.3.6 --- Triparental mating of Agrobacterium tumefaciens LBA4404/pAL4404 --- p.35 / Chapter 3.3.7 --- Tobacco transformation and regeneration --- p.36 / Chapter 3.3.8 --- GUS assay --- p.37 / Chapter 3.3.9 --- Genomic DNA isolation --- p.37 / Chapter 3.3.10 --- PCR amplification and detection of transgene --- p.38 / Chapter 3.3.11 --- Southern blot analysis --- p.38 / Chapter 3.3.12 --- Total seeds RNA isolation --- p.39 / Chapter 3.3.13 --- RT-PCR --- p.39 / Chapter 3.3.14 --- Northern blot analysis --- p.40 / Chapter 3.3.15 --- Protein extraction and SDS-PAGE --- p.40 / Chapter 3.3.16 --- Western blot analysis --- p.41 / Chapter 3.4 --- Expression in Arabidopsis system --- p.42 / Chapter 3.4.1 --- Plant materials --- p.42 / Chapter 3.4.2 --- Bacterial strains --- p.42 / Chapter 3.4.3 --- Chimeric gene construction --- p.42 / Chapter 3.4.3.1 --- The cloning of pBKPhasp-sp/His/EK/p42/Phast (DH) --- p.43 / Chapter 3.4.3.2 --- The cloning of pTZPhaSp/His/EK/p42/Phast (EH) --- p.45 / Chapter 3.4.3.3 --- The cloning of pBKPhasp-sp/His/EK/flgp42/Phast (DHF) and pTZPhasp/His/EK/flgp42/Phast (EHF) --- p.45 / Chapter 3.4.4 --- Confirmation of sequence fidelity of chimeric genes --- p.45 / Chapter 3.4.5 --- Cloning of chimeric gene into Agrobacterium binary vector --- p.49 / Chapter 3.4.6 --- Transformation of Agrobacterium tumefaciens GV3101/pMP90 with chimeric gene constructs --- p.49 / Chapter 3.4.7 --- Arabidopsis Transformation --- p.49 / Chapter 3.4.8 --- Vacuum infiltration transformation --- p.50 / Chapter 3.4.9 --- Selection of successful transformants --- p.51 / Chapter 3.4.10 --- Selection for homozygous plants with single gene insertion --- p.51 / Chapter 3.4.11 --- GUS assay --- p.52 / Chapter 3.4.12 --- Genomic DNA isolation --- p.52 / Chapter 3.4.13 --- PCR amplification and detection of transgenes --- p.52 / Chapter 3.4.14 --- Southern Blot analysis --- p.52 / Chapter 3.4.15 --- Total siliques RNA isolation --- p.53 / Chapter 3.4.16 --- RT-PCR --- p.53 / Chapter 3.4.17 --- Northern blot analysis --- p.53 / Chapter 3.4.17 --- Protein extraction and SDS-PAGE --- p.54 / Chapter 3.4.18 --- Western blot analysis --- p.54 / Chapter 3.5 --- In vitro transcription and translation --- p.54 / Chapter 3.5.1 --- In vitro transcription --- p.54 / Chapter 3.5.2 --- In vitro translation --- p.55 / Chapter 3.6 --- Particle bombardment of GUS fusion gene --- p.56 / Chapter 3.6.1 --- Chimeric gene constructs --- p.56 / Chapter 3.6.2 --- Particle bombardment using snow bean cotyledon --- p.61 / Chapter Chapter 4: --- Results --- p.63 / Chapter 4.1 --- Tobacco system --- p.63 / Chapter 4.1.1 --- Chimeric gene constructs --- p.63 / Chapter 4.1.2 --- Tobacco transformation and regeneration --- p.65 / Chapter 4.1.3 --- GUS activity assay --- p.67 / Chapter 4.1.4 --- Molecular analysis of transgene integration --- p.68 / Chapter 4.1.4.1 --- Genomic DNA extraction and PCR --- p.68 / Chapter 4.1.4.2 --- Southern blot analysis --- p.70 / Chapter 4.1.5 --- Molecular analysis of transgene expression --- p.72 / Chapter 4.1.5.1 --- Total RNA isolation and RT-PCR --- p.72 / Chapter 4.1.5.2 --- Northern blot analysis --- p.75 / Chapter 4.1.6 --- Genomic PCR to confirm whole gene transfer --- p.76 / Chapter 4.1.7 --- Biochemical analysis of transgene expression --- p.78 / Chapter 4.1.7.1 --- Protein extraction and SDS-PAGE --- p.78 / Chapter 4.1.7.2 --- Western blot analysis --- p.78 / Chapter 4.2 --- Arabidopsis system --- p.83 / Chapter 4.2.1 --- Chimeric gene constructs --- p.83 / Chapter 4.2.2 --- Arabidopsis transformation and selection --- p.85 / Chapter 4.2.3 --- Selection of transgenic plants --- p.87 / Chapter 4.2.4 --- Assay of GUS activity --- p.91 / Chapter 4.2.5 --- Molecular analysis of transgene integration --- p.92 / Chapter 4.2.5.1 --- Genomic DNA extraction and PCR --- p.92 / Chapter 4.2.5.2 --- Southern blot analysis --- p.96 / Chapter 4.2.6 --- Molecular analysis of transgene expression --- p.99 / Chapter 4.2.6.1 --- Total RNA isolation and RT-PCR --- p.99 / Chapter 4.2.6.2 --- Northern blot analysis --- p.106 / Chapter 4.2.7 --- Genomic PCR for confirmation of whole gene transfer --- p.107 / Chapter 4.2.8 --- Biochemical analysis of transgene expression --- p.108 / Chapter 4.2.8.1 --- Protein extraction and SDS-PAGE --- p.108 / Chapter 4.2.8.2 --- Western blot analysis --- p.108 / Chapter 4.3 --- In vitro transcription and translation --- p.112 / Chapter 4.4 --- Particle bombardment of p42/ GUS fusion gene --- p.115 / Chapter Chapter 5: --- Discussion and Future perspectives --- p.117 / Chapter 5.1 --- Failure in detecting transgene expression --- p.117 / Chapter 5.2 --- Poor transgene expression --- p.120 / Chapter 5.2.1 --- Bacillus thuringiensis toxin and green fluorescent protein --- p.120 / Chapter 5.2.2 --- AT-richness --- p.121 / Chapter 5.2.3 --- Deleterious sequence - AUUUA --- p.123 / Chapter 5.2.4 --- Presence of AAUAAA or AAUAAA-like motifs --- p.125 / Chapter 5.2.5 --- Codon usage --- p.126 / Chapter 5.3 --- Future perspectives --- p.127 / Chapter Chapter 6: --- Conclusion --- p.129 / References --- p.131

O objetivo deste trabalho foi estudar a resposta imune, quanto ao nível e à avidez dos anticorpos IgG, dirigidos contra o antígeno recombinante derivada da Proteína 1 de Superfície de Merozoíto de Plasmodium vivax (PvMSP119) em indivíduos residentes em diferentes áreas endêmicas do Brasil, empregando o teste ELISA. Para tanto, foram estudadas amostras de indivíduos expostos à malária, infectados ou não e em acompanhamento terapêutico. Na padronização das condições de reação, obteve-se uma sensibilidade de 95,00% em amostras de pacientes com gota espessa positiva para P. vivax e uma especificidade de 99,50% em amostras de indivíduos saudáveis e com outras patologias. Entre as amostras de pacientes com P. falciparum, 7,14% foram reagentes. O estudo dos diferentes grupos de pacientes com malária vivax mostrou haver diferença significante entre os primo infectados e aqueles com episódios anteriores de malária, sendo os níveis (IR) e avidez (IA) de IgG mais baixos nos primo infectados, embora os níveis de anticorpos já estivessem elevados nesses pacientes. A predominância de IgG anti-PvMSP119 de baixa avidez nos pacientes primo infectados por P. vivax, sugere um baixo grau de proteção, mesmo na presença de elevados níveis de anticorpos observados já no início da infecção. A análise dos indivíduos não infectados mostrou haver uma associação negativa dos resultados de IR com o tempo decorrido desde o último episódio de malária e associação positiva com o número de malárias anteriores. Em relação aos IA houve associação positiva com ambos os parâmetros, nos pacientes que haviam tido malária até, no máximo, seis meses antes da coleta. Entre os pacientes que haviam apresentado episódios de malária anteriores, observaram-se níveis mais baixos de anticorpos IgG anti-PvMSP119 em indivíduos com alta exposição à malária, quando comparados a moradores de áreas com baixa transmissão. Em relação à avidez, foram encontrados índices mais elevados nas áreas de maior transmissão. Considerando-se o município de Alta Floresta, nas regiões de garimpo e próximas à mata, obtiveram-se altos índices de positividade com níveis e avidez dos anticorpos mais elevados que nas demais regiões. Não foi observada correlação entre níveis e avidez dos anticorpos IgG anti-PvMSP119. / The aim of this work was to study the level and avidity of IgG antibodies specific to Plasmodium vivax using the recombinant protein corresponding to 19kDa C-terminal of the merozoite surface protein 1 region (PvMSP119) in individuals living in distinct malaria endemic areas, using ELISA test. Thus, samples from individuals exposed to malaria, with patent infection or not were evaluated. The reaction conditions were standardized, yielding 95.00% sensitivity with sera from P. vivax infected patients and 99.50% specificity with sera from individuals non-exposed to P. vivax malaria. Just 7.14% of patient samples with P. falciparum malaria reacted to PvMSP119. The investigation of different groups of vivax malaria patients showed significant differences between patients with primo infection and those with past malaria episodes. The levels and avidity of IgG were lower in primo infected ones. The predominance of low avidity IgG in P. vivax primo infected patients may suggest low grade of protection even in high level antibody sera. The analysis of non-infected subjects showed a negative association of IgG levels and time elapsed since last malaria episode, and a positive association to the number of malaria episodes. For individuals who had had last malaria episode till maximum six months before the collecting of blood samples, avidity indexes showed positive association for both parameters described before. Individuals sporadically exposed to malaria transmission (Belém group) and who experienced their last episode by P. vivax had significant high levels and proportions of specific antibodies when compared to subjects continuously exposed (Alta Floresta group). Otherwise, higher avidity levels were detected in high transmission areas. In god mines and forest areas of Alta Floresta, higher IgG and avidity levels were obtained, as compared to the other regions of the municipality. No correlation was observed between anti-PvMSP119 IgG levels and avidity levels.

No description available.

O objetivo deste trabalho foi estudar a resposta imune, quanto ao nível e à avidez dos anticorpos IgG, dirigidos contra o antígeno recombinante derivada da Proteína 1 de Superfície de Merozoíto de Plasmodium vivax (PvMSP119) em indivíduos residentes em diferentes áreas endêmicas do Brasil, empregando o teste ELISA. Para tanto, foram estudadas amostras de indivíduos expostos à malária, infectados ou não e em acompanhamento terapêutico. Na padronização das condições de reação, obteve-se uma sensibilidade de 95,00% em amostras de pacientes com gota espessa positiva para P. vivax e uma especificidade de 99,50% em amostras de indivíduos saudáveis e com outras patologias. Entre as amostras de pacientes com P. falciparum, 7,14% foram reagentes. O estudo dos diferentes grupos de pacientes com malária vivax mostrou haver diferença significante entre os primo infectados e aqueles com episódios anteriores de malária, sendo os níveis (IR) e avidez (IA) de IgG mais baixos nos primo infectados, embora os níveis de anticorpos já estivessem elevados nesses pacientes. A predominância de IgG anti-PvMSP119 de baixa avidez nos pacientes primo infectados por P. vivax, sugere um baixo grau de proteção, mesmo na presença de elevados níveis de anticorpos observados já no início da infecção. A análise dos indivíduos não infectados mostrou haver uma associação negativa dos resultados de IR com o tempo decorrido desde o último episódio de malária e associação positiva com o número de malárias anteriores. Em relação aos IA houve associação positiva com ambos os parâmetros, nos pacientes que haviam tido malária até, no máximo, seis meses antes da coleta. Entre os pacientes que haviam apresentado episódios de malária anteriores, observaram-se níveis mais baixos de anticorpos IgG anti-PvMSP119 em indivíduos com alta exposição à malária, quando comparados a moradores de áreas com baixa transmissão. Em relação à avidez, foram encontrados índices mais elevados nas áreas de maior transmissão. Considerando-se o município de Alta Floresta, nas regiões de garimpo e próximas à mata, obtiveram-se altos índices de positividade com níveis e avidez dos anticorpos mais elevados que nas demais regiões. Não foi observada correlação entre níveis e avidez dos anticorpos IgG anti-PvMSP119. / The aim of this work was to study the level and avidity of IgG antibodies specific to Plasmodium vivax using the recombinant protein corresponding to 19kDa C-terminal of the merozoite surface protein 1 region (PvMSP119) in individuals living in distinct malaria endemic areas, using ELISA test. Thus, samples from individuals exposed to malaria, with patent infection or not were evaluated. The reaction conditions were standardized, yielding 95.00% sensitivity with sera from P. vivax infected patients and 99.50% specificity with sera from individuals non-exposed to P. vivax malaria. Just 7.14% of patient samples with P. falciparum malaria reacted to PvMSP119. The investigation of different groups of vivax malaria patients showed significant differences between patients with primo infection and those with past malaria episodes. The levels and avidity of IgG were lower in primo infected ones. The predominance of low avidity IgG in P. vivax primo infected patients may suggest low grade of protection even in high level antibody sera. The analysis of non-infected subjects showed a negative association of IgG levels and time elapsed since last malaria episode, and a positive association to the number of malaria episodes. For individuals who had had last malaria episode till maximum six months before the collecting of blood samples, avidity indexes showed positive association for both parameters described before. Individuals sporadically exposed to malaria transmission (Belém group) and who experienced their last episode by P. vivax had significant high levels and proportions of specific antibodies when compared to subjects continuously exposed (Alta Floresta group). Otherwise, higher avidity levels were detected in high transmission areas. In god mines and forest areas of Alta Floresta, higher IgG and avidity levels were obtained, as compared to the other regions of the municipality. No correlation was observed between anti-PvMSP119 IgG levels and avidity levels.

Streptococcus agalactiae est la première cause d’infections invasives chez le nouveau né et, malgré la mise en place de stratégies de prévention, cette bactérie reste le principal agent étiologique des infections néonatales. Les souches de séquence type 17, dites hyper-virulentes, sont particulièrement associées avec les méningites, type d’infection ayant des conséquences lourdes en terme de mortalité et morbidité. Ce clone possède des caractéristiques uniques, telle que la fixation au fibrinogène, ainsi qu’un répertoire de protéines de surface qui lui sont spécifiques. Parmi ces protéines, Srr2 appartient à une famille de larges glycoprotéines streptococcales et staphylococcales impliquées dans la pathogénicité. Un domaine central de Srr2, le domaine BR, est responsable de la fixation spécifique du fibrinogène par le clone ST-17, ainsi qu’au plasminogène et à divers composants de la matrice extracellulaire. Cette protéine promeut ainsi l’adhésion et le franchissement des barrières cellulaires. L’interaction de Srr2 avec les systèmes fibrinolytique et de coagulation de l’hôte favorise la dissémination bactérienne par l’activation de la fibrinolyse, et la persistance de la bactérie dans l’organisme par la formation d’agrégats bactériens. La liaison de Srr2 avec le fibrinogène semble également promouvoir la persistance bactérienne en favorisant l’internalisation et la survie dans les macrophages. Ainsi, la protéine Srr2 confère un avantage pour le processus infectieux du clone ST-17 dans l’hôte, et constitue une cible vaccinale intéressante pour la prévention des infections à S. agalactiae. / Streptococcus agalactiae is the leading cause of invasive infections in neonates. Despite the implementation of prevention strategies, this bacterium remains the main etiological agent of neonatal infections. Hyper-virulent sequence-type 17 strains are particularly associated with meningitis, a type of infection with serious consequences in terms of mortality and morbidity. This clone has unique characteristics, such as fibrinogen binding, and a panel of specific surface proteins. Among these proteins, Srr2 belongs to a family of large streptococcal and staphylococcal glycoproteins involved in pathogenicity. A central domain of Srr2, BR domain, is responsible for the specific binding of fibrinogen by the ST -17 clone and also binds plasminogen and various components of the extracellular matrix. Thereby, it promotes adhesion and crossing of cellular barriers. The interaction of Srr2 with fibrinolytic and coagulation systems of the host could promote bacterial spread through the activation of fibrinolysis and the persistence of the bacteria in the host by the formation of bacterial aggregates. The interaction of Srr2 with fibrinogen also seems to promote bacterial persistence in promoting the internalization and survival of the bacteria in macrophages. Thus, Srr2 confers an advantage to the infectious process of the ST- 17 clone in the host and is an attractive vaccine candidate for the prevention of S. agalactiae infections.

Bakterielle Zellhüllenproteine (S-Layer) können als formgebende Muster für die bottom-up Materialsynthese Verwendung finden. Auf S-Layern von Bacillus sphaericus und Sporosarcina ureae lassen sich nasschemisch Platin- bzw. Palladiumcluster abscheiden, die sich durch ihren gleichmäßig geringen Durchmesser und ihre hohe laterale Dichte auszeichnen. Am Beginn der vorliegenden Arbeit steht die Charakterisierung des Proteintemplates, welches grundlegenden Einfluss auf die sich bildenden Edelmetallcluster hat. Die Topographie der S-Layeroberfläche wird atomkraftmikroskopisch untersucht. Durch Photoemissions- und NEXAFS-Spektroskopie werden Aussagen zur elektronischen Struktur des Proteins gewonnen, die nach entsprechender Interpretation Erklärungen für das Verhalten des Proteintemplates liefern. Daneben sind Syntheseparameter ausschlaggebend für das Erscheinungsbild des dispersen Metalls. Insbesondere der Einfluss des Reduktionsmittels auf die Clustergröße wird elektronenmikroskopisch und durch Kleinwinkelstreuung untersucht. Die katalytische Aktivität von auf gamma-Al2O3 und SiC immobilisierten metallisierten S-Layern für die Oxidation ausgewählter Kohlenwasserstoffe und Kohlenmonoxid wird bestimmt. Außerdem werden Verfahren zur Erzeugung von Gold- und Silberclustern auf S-Layern vorgestellt.