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Abstract(s)
A Helicobacter pylori é uma bactéria que coloniza o estômago humano e pode levar ao desenvolvimento de patologias gástricas como a gastrite crónica, úlceras pépticas, linfoma de MALT e o adenocarcinoma gástrico. Devido à sua diversidade genética e à robusta estratégia de infeção, tem sido dificil o desenvolvimento de uma vacina, para prevenir e erradicar a infeção, bem como o desenvolvimento de testes de diagnóstico eficazes. A proteína de ativação de neutrófilos (NAP) da H. pylori, constitui um dos principais fatores de virulência, que devido à sua capacidade de ativar neutrófilos, representa um importante papel no processo da infeção crónica. Neste trabalho, observou-se por diversos métodos de bioinformática que a NAP apresenta alguma diversidade genética mas uma sequência proteica conservada, tendo-se estimado as regiões teoricamente mais antigénicas e que devem ser consideradas no desenho de testes de diagnóstico e de vacinas baseado neste antigénio. De forma a avaliar o potencial desta proteína como antigénio na conceção de vacinas e de testes de diagnóstico avaliou-se experimentalmente a imunovariabilidade da NAP. Para isso, foram formuladas duas vacinas, uma proteica e outra de DNA, baseadas na inserção do gene da NAP da estirpe de referência H. pylori 26695, no plasmídeo procariota pQE30 e no plasmídeo eucariota pVAX. Observou-se em murganhos imunizados com estas vacinas uma resposta imune equilibrada Th1 e Th2. Observou-se de igual forma, em Western blots, o reconhecimento da NAP extraída de diversas estirpes de H. pylori obtidas de pacientes de diversos pontos do globo, pelos anticorpos policlonais obtidos da imunização com a NAP da estirpe H. pylori 26695. Desta forma, confirmou-se a elevada conservação imunogénica desta proteína, realçando a relevância de utilização deste alvo na conceção de vacinas e de testes de diagnóstico.
Helicobacter pylori is a bacterium which colonizes the human stomach and can lead to the development of gastric pathologies such as chronic gastritis, peptic ulcers, gastric MALT lymphoma and adenocarcinoma. Due to their genetic diversity and robust strategy of infection of this bacterium, the development of a vaccine to prevent and eradicate the infection and the development of efficient diagnostic tests, have been difficult. Protein activation of neutrophils (NAP) of H. pylori, constitutes a major virulence factors, which because of its ability to activate neutrophils, plays an important role in the process of chronic infection. In this work, it was observed by several bioinformatics methods that NAP presents some genetic diversity but a protein conserved sequence, having been estimated theoretically the most antigenic regions should be considered in the design of diagnostic tests and vaccine based on this antigen. In order to evaluate the potential this protein as an antigen in designing of vaccines and diagnostic tests is evaluated experimentally the imunovariability of the NAP. For this, two vaccines, of one protein and another DNA, based on the insertion of the gene NAP of reference strain H. pylori 26695 in prokaryotic plasmid pQE30 and eukaryotic plasmid pVAX, were formulated. Was observed in mice immunized with these vaccines a balanced Th1 and Th2 immune response. The same way, was observed, in Western blots the recognition of NAP extracted from different H. pylori strains obtained from patients from different parts of the globe, for the polyclonal antibodies obtained by immunization with the NAP of H. pylori strain 26695. This way, confirmed the high immunogenic conservation this protein, highlighting the relevance of using this target in designing of vaccines and diagnostic tests.
Helicobacter pylori is a bacterium which colonizes the human stomach and can lead to the development of gastric pathologies such as chronic gastritis, peptic ulcers, gastric MALT lymphoma and adenocarcinoma. Due to their genetic diversity and robust strategy of infection of this bacterium, the development of a vaccine to prevent and eradicate the infection and the development of efficient diagnostic tests, have been difficult. Protein activation of neutrophils (NAP) of H. pylori, constitutes a major virulence factors, which because of its ability to activate neutrophils, plays an important role in the process of chronic infection. In this work, it was observed by several bioinformatics methods that NAP presents some genetic diversity but a protein conserved sequence, having been estimated theoretically the most antigenic regions should be considered in the design of diagnostic tests and vaccine based on this antigen. In order to evaluate the potential this protein as an antigen in designing of vaccines and diagnostic tests is evaluated experimentally the imunovariability of the NAP. For this, two vaccines, of one protein and another DNA, based on the insertion of the gene NAP of reference strain H. pylori 26695 in prokaryotic plasmid pQE30 and eukaryotic plasmid pVAX, were formulated. Was observed in mice immunized with these vaccines a balanced Th1 and Th2 immune response. The same way, was observed, in Western blots the recognition of NAP extracted from different H. pylori strains obtained from patients from different parts of the globe, for the polyclonal antibodies obtained by immunization with the NAP of H. pylori strain 26695. This way, confirmed the high immunogenic conservation this protein, highlighting the relevance of using this target in designing of vaccines and diagnostic tests.
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Keywords
Helicobacter pylori Proteína de ativação de neutrófilos Antigénio Vacina Testes de diagnóstico Imunovariabilidade Neutrophil activation protein Antigen Vaccine Diagnostic tests Imunovariability