RESUMO
Helicobacter pylori, the major cause of gastric cancer, have mechanisms that allow colonization of the inhospitable gastric mucosa, including enzymes such as superoxide dismutase (SOD) which protect against reactive oxygen species. As SOD is essential for in vivo colonization, we theorized it might constitute a viable vaccine target. H. pylori SOD was expressed in E. coli and a purified recombinant protein used to vaccinate mice, prior to live H. pylori challenge. Partial protective immunity was induced, similar to that commonly observed with other antigens tested previously. This suggests SOD may have utility in a combination vaccine comprising several protective antigens.
Assuntos
Antígenos de Bactérias/imunologia , Vacinas Bacterianas/imunologia , Infecções por Helicobacter/prevenção & controle , Helicobacter pylori/enzimologia , Superóxido Dismutase/imunologia , Animais , Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/genética , Escherichia coli/genética , Escherichia coli/imunologia , Feminino , Infecções por Helicobacter/imunologia , Helicobacter pylori/imunologia , Imunidade Humoral , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Superóxido Dismutase/genéticaRESUMO
The aim of this study was to determine the diversity of Klebsiella pneumoniae capsular serotypes in an Australian setting. Consecutive (n = 293) nonrepetitive isolates of K. pneumoniae from a large teaching hospital laboratory were analyzed. The majority of isolates were from urinary specimens (60.8%); the next most common source was sputum (14.3%), followed by blood (14%). Serotyping revealed a wide range of capsule types. K54 (17.1%), K28 (4.1%), and K17 (3.1%) were the most common, and K54 isolates displayed a high degree of clonality, suggesting a common, nosocomial source. In vitro, one K54 isolate was more adherent to urinary catheters and HEp-2 cells than four other tested isolates; it was slightly more resistant to chlorhexidine but was more susceptible to drying than heavily encapsulated strains. This is the first seroprevalence survey of K. pneumoniae to be performed on Australian isolates, and the high level of diversity of serotypes suggests that capsule-based immunoprophylaxis might not be useful for Australia. In addition there are significant differences in the predominance of specific serotypes compared to the results of surveys performed overseas, which has important implications for capsule-based immunoprophylaxis aimed at a global market.