Embora a imunização gênica apresente vantagens sobre as vacinas convencionais, nem sempre a produção de anticorpos e a conseqüente proteção conferida pelo sistema imune contra o antígeno de interesse são satisfatórias. As causas da baixa eficácia da imunização gênica, nestes casos, ainda são pouco conhecidas, porém um dos pontos mais relevantes em todo o processo é a eficiência da transfecção do DNA. O sucesso desta metodologia depende do estabelecimento de um sistema de entrega de gene eficiente e seguro. De acordo com a teoria proposta de Kuhn et al. (1999), baixas concentrações de moléculas anfifílicas podem ser usadas para neutralizar a carga do DNA, sem a formação de lipossomos. Este trabalho teve como objetivo avaliar o uso do lipídio catiônico dimetildioctadecil brometo de amônio (DDAB) como neutralizador da carga do DNA para a imunização de camundongos. Para a realização dos experimentos, um plasmídeo expressando a proteína do capsídeo (CA) do vírus da artrite encefalite caprina (CAEV), sob o comando do promotor citomegalovírus humano (CMV), foi utilizado nas imunizações. Os camundongos foram divididos em cinco grupos e receberam, via subcutânea, três inoculações de 10 μg de DNA linear (grupo 1), DNA linear mínimo (grupo 2), DNA circular (grupo 3) associados a 2,7 μg de DDAB ou DNA circular nu (grupo 4). O grupo controle foi inoculado com 2,7 μg de DDAB em solução fisiológica. Os camundongos imunizados com o plasmídeo na forma linear associado ao DDAB apresentaram maiores títulos de anticorpos CA que os inoculados com a forma circular ou linear mínima. Os dados sugerem que o lipídio catiônico DDAB tem potencial de uso como veículo de transfecção gênica em animais. / Genetic immunization has several advantages over conventional vaccines. However, antibody production and protection against the antigen of interest are often not satisfactory. In these cases, the causes of the low effectiveness of the genetic immunization are still poorly understood. One of the most relevant points in the immunization process is the DNA delivery. A successful DNA vaccine depends on the establishment of an efficient and safe gene delivery system. In accordance with Kuhn et al. (1999), low concentrations of amphiphilic molecules can be used to neutralize the DNA charge without the formation of liposomes. The aim of this study was to examine the effect of cationic lipid dimethildioctadecyl-ammonium bromide (DDAB) as a charge neutralizer for DNA for the immunization in mice. A plasmid expressing the capsid protein (CA) of caprine arthritis encephalitis virus (CAEV) under the control of the human cytomegalovirus immediate early promoter (hCMVie1) was used in the immunization. Mice were grouped and immunized with three injections of either 10 μg of linear DNA (group 1), minimal linear DNA (group 2) or circular DNA (group 3) associated with 2,7 μg of DDAB or naked circular DNA (group 4). The control group received 2,7 μg of DDAB diluted in physiologic solution. Mice immunized with DNA in linear form associated with DDAB developed higher titers of antibodies against CA than the animals immunized with the circular or minimal linear form. The data suggest that lipidic cationic DDAB could be a useful delivery system for genetic immunization.

Embora a imunização gênica apresente vantagens sobre as vacinas convencionais, nem sempre a produção de anticorpos e a conseqüente proteção conferida pelo sistema imune contra o antígeno de interesse são satisfatórias. As causas da baixa eficácia da imunização gênica, nestes casos, ainda são pouco conhecidas, porém um dos pontos mais relevantes em todo o processo é a eficiência da transfecção do DNA. O sucesso desta metodologia depende do estabelecimento de um sistema de entrega de gene eficiente e seguro. De acordo com a teoria proposta de Kuhn et al. (1999), baixas concentrações de moléculas anfifílicas podem ser usadas para neutralizar a carga do DNA, sem a formação de lipossomos. Este trabalho teve como objetivo avaliar o uso do lipídio catiônico dimetildioctadecil brometo de amônio (DDAB) como neutralizador da carga do DNA para a imunização de camundongos. Para a realização dos experimentos, um plasmídeo expressando a proteína do capsídeo (CA) do vírus da artrite encefalite caprina (CAEV), sob o comando do promotor citomegalovírus humano (CMV), foi utilizado nas imunizações. Os camundongos foram divididos em cinco grupos e receberam, via subcutânea, três inoculações de 10 μg de DNA linear (grupo 1), DNA linear mínimo (grupo 2), DNA circular (grupo 3) associados a 2,7 μg de DDAB ou DNA circular nu (grupo 4). O grupo controle foi inoculado com 2,7 μg de DDAB em solução fisiológica. Os camundongos imunizados com o plasmídeo na forma linear associado ao DDAB apresentaram maiores títulos de anticorpos CA que os inoculados com a forma circular ou linear mínima. Os dados sugerem que o lipídio catiônico DDAB tem potencial de uso como veículo de transfecção gênica em animais. / Genetic immunization has several advantages over conventional vaccines. However, antibody production and protection against the antigen of interest are often not satisfactory. In these cases, the causes of the low effectiveness of the genetic immunization are still poorly understood. One of the most relevant points in the immunization process is the DNA delivery. A successful DNA vaccine depends on the establishment of an efficient and safe gene delivery system. In accordance with Kuhn et al. (1999), low concentrations of amphiphilic molecules can be used to neutralize the DNA charge without the formation of liposomes. The aim of this study was to examine the effect of cationic lipid dimethildioctadecyl-ammonium bromide (DDAB) as a charge neutralizer for DNA for the immunization in mice. A plasmid expressing the capsid protein (CA) of caprine arthritis encephalitis virus (CAEV) under the control of the human cytomegalovirus immediate early promoter (hCMVie1) was used in the immunization. Mice were grouped and immunized with three injections of either 10 μg of linear DNA (group 1), minimal linear DNA (group 2) or circular DNA (group 3) associated with 2,7 μg of DDAB or naked circular DNA (group 4). The control group received 2,7 μg of DDAB diluted in physiologic solution. Mice immunized with DNA in linear form associated with DDAB developed higher titers of antibodies against CA than the animals immunized with the circular or minimal linear form. The data suggest that lipidic cationic DDAB could be a useful delivery system for genetic immunization.

Embora a imunização gênica apresente vantagens sobre as vacinas convencionais, nem sempre a produção de anticorpos e a conseqüente proteção conferida pelo sistema imune contra o antígeno de interesse são satisfatórias. As causas da baixa eficácia da imunização gênica, nestes casos, ainda são pouco conhecidas, porém um dos pontos mais relevantes em todo o processo é a eficiência da transfecção do DNA. O sucesso desta metodologia depende do estabelecimento de um sistema de entrega de gene eficiente e seguro. De acordo com a teoria proposta de Kuhn et al. (1999), baixas concentrações de moléculas anfifílicas podem ser usadas para neutralizar a carga do DNA, sem a formação de lipossomos. Este trabalho teve como objetivo avaliar o uso do lipídio catiônico dimetildioctadecil brometo de amônio (DDAB) como neutralizador da carga do DNA para a imunização de camundongos. Para a realização dos experimentos, um plasmídeo expressando a proteína do capsídeo (CA) do vírus da artrite encefalite caprina (CAEV), sob o comando do promotor citomegalovírus humano (CMV), foi utilizado nas imunizações. Os camundongos foram divididos em cinco grupos e receberam, via subcutânea, três inoculações de 10 μg de DNA linear (grupo 1), DNA linear mínimo (grupo 2), DNA circular (grupo 3) associados a 2,7 μg de DDAB ou DNA circular nu (grupo 4). O grupo controle foi inoculado com 2,7 μg de DDAB em solução fisiológica. Os camundongos imunizados com o plasmídeo na forma linear associado ao DDAB apresentaram maiores títulos de anticorpos CA que os inoculados com a forma circular ou linear mínima. Os dados sugerem que o lipídio catiônico DDAB tem potencial de uso como veículo de transfecção gênica em animais. / Genetic immunization has several advantages over conventional vaccines. However, antibody production and protection against the antigen of interest are often not satisfactory. In these cases, the causes of the low effectiveness of the genetic immunization are still poorly understood. One of the most relevant points in the immunization process is the DNA delivery. A successful DNA vaccine depends on the establishment of an efficient and safe gene delivery system. In accordance with Kuhn et al. (1999), low concentrations of amphiphilic molecules can be used to neutralize the DNA charge without the formation of liposomes. The aim of this study was to examine the effect of cationic lipid dimethildioctadecyl-ammonium bromide (DDAB) as a charge neutralizer for DNA for the immunization in mice. A plasmid expressing the capsid protein (CA) of caprine arthritis encephalitis virus (CAEV) under the control of the human cytomegalovirus immediate early promoter (hCMVie1) was used in the immunization. Mice were grouped and immunized with three injections of either 10 μg of linear DNA (group 1), minimal linear DNA (group 2) or circular DNA (group 3) associated with 2,7 μg of DDAB or naked circular DNA (group 4). The control group received 2,7 μg of DDAB diluted in physiologic solution. Mice immunized with DNA in linear form associated with DDAB developed higher titers of antibodies against CA than the animals immunized with the circular or minimal linear form. The data suggest that lipidic cationic DDAB could be a useful delivery system for genetic immunization.

Puumala viruses, a member of the Hantavirus genus in the Bunyaviridae family, are enveloped by a lipid bilayer and possesses a tripartite single stranded RNA genome with negative polarity. The hantaviruses encode four proteins: a nucleocapsid protein (N), two membrane spanning glycoproteins (GN and GC) and a RNA dependent RNA polymerase (RdRp). Hantaviruses cause two forms of diseases, hemorrhagic fever with renal syndrome (HFRS) in Europe and Asia, and hantavirus pulmonary syndrome (HPS) in the Americas. The hantaviruses are mainly rodent borne, and humans are mostly infected by inhalation of aerosolized rodent secrete. Human Puumala virus infection results in nephropathia epidemica (NE), a mild haemorrhagic disease. It is of importance to have a good understanding of the epidemiology and genetics of these viruses for the development of new diagnostic methods and for future vaccine development. In this thesis we determined the complete viral genome sequence and characterized the structural proteins based on studies of expression and glycosylation patterns, for a unique human virus isolate; performed a genomic analysis of local Puumala viruses and their individual rodent host, Clethrionomys glareolus, from six different locations was performed. It was seen that the virus genetic variation between different locations could be stable over relatively large distances while there could be large variation over a short distance. For the bank voles no such variation could be seen; developed and evaluated Genetic vaccines, based on PCR-generated linear DNA. We showed that it was important to protect these fragments against nuclease degradation at that attachment of a nuclear localization signal peptide further improved the immune response. We also designed, fabricated and evaluated a 2000 probe cDNA-microarray for identification and differentiation of hantaviruses. The chips was based on 12 different strains of six hantaviruses and could differentiate between both different hantaviruses and strains within one hantavirus serotype.

This thesis reports the viability of E. coli cell extracts prepared using equipment that is both common to biotechnology laboratories and able to process small volume samples and expression of proteins containing unnatural amino acids (UAAs) at higher level using PCR amplified linear DNA templates (LETs) in cell-free protein synthesis (CFPS) system. E. coli-based cell extracts are a vital component of inexpensive and high-yielding CFPS reactions. However, effective preparation of E. coli cell extract is limited to high-pressure homogenizers (French press style or impinge-style) or bead mill homogenizers, which all require a significant capital investment. This work specifically assessed the following capital cost lysis techniques: (1) sonication, (2) bead vortex mixing, (3) freeze-thaw cycling, and (4) lysozyme incubation to prepare E. coli cell extract for CFPS. In this work, simple shake flask fermentation with a commercially available E. coli strain was used. Additionally, the RNA polymerase was over expressed in the E. coli cells prior to lysis which eliminated the need to add independently purified RNA polymerase to the CFPS reaction. As a result, high yielding E. coli-based cell extract was prepared using equipment requiring reduced capital investment and common to biotechnology laboratories. To our knowledge, this is the first successful prokaryote-based CFPS reaction to be carried out with extract prepared by sonication or bead vortex mixing. LETs are an attractive alternative to plasmids for site-specific incorporation of unnatural amino acids in proteins in the CFPS system because of their short preparation time and ease of production. However, major limitations associated with LETs are: (1) their degradation by RecBCD enzyme present in the cell-extract used for CFPS and (2) high CFPS energy costs. In this work, we report the optimization of LET-based CFPS for improved protein yield by inhibiting the RecBCD enzyme with small inhibitor molecules resulting in three fold increment in yield of protein containing UAA. We also assessed alternative energy sources such as glucose, fructose-1,6-bisphospate, creatine phosphate/creatine kinase, and high glutamate salt for cost reduction. This work could be important for high-throughput applications based on linear expression templates. This work demonstrates simple E. coli extract preparation and improved yield with linear expression templates for further advancements of cell-free protein synthesis system.

Unnatural amino acids (uAA) expand the structural and functional possibilities of proteins. Numerous previous studies have demonstrated uAA as a powerful tool for protein engineering, but challenges also remain. Three notable such challenges include: (1) the fitness of uAA-incorporated proteins are difficult to predict and time-consuming to screen with conventional methods, (2) uAA incorporation in difficult-to-express proteins (e.g. membrane proteins such as G-protein coupled receptors) remain challenging, and (3) the incorporation of multiple types of uAA are still limited. In response, we pose cell-free protein synthesis (CFPS), a rapid and versatile in vitro expression system, as a platform to explore solutions to these challenges. The "cell-free" nature of CFPS enables it to accelerate protein expression and tolerate extensive modifications to its translational environment. In this work, these advantages were utilized to address the aforementioned challenges by: (1) rapidly expressing and screening uAA-containing proteins, (2) incorporating uAA in functional G-protein coupled receptor in the presence of membrane-mimicking lipid additives, and (3) engineer the translational environment extensively towards multiple uAA incorporation.