Imunovariabilidade da proteína ativadora de neutrófilos da Helicobacter pylori

Abstract

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.

Date of Award	2014
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Cecília Ribeiro da Cruz Calado (Supervisor)