The deletion of omp19 gene of brucella abortus 2308 reduces its survival in mouse macrophage and in mice

Abstract

The aim of this study is to investigate the role of outer membrane protein Omp19 of Brucella in its pathogenesis. In this research, the Brucella 2308 ΔOmp19 deletion mutant was constructed and its intracellular survivability was evaluated in murine macrophages RAW264.7 and BALB/c mice. We also analyzed the lysosomal fusion induced by and cytotoxicity of Brucella in murine macrophages RAW264.7. The results showed that the Brucella 2308 ΔOmp19 induced higher levels of immunoprotective cytokines in vitro than Brucella 2308, and the number of intracellular bacteria in RAW264.7 macrophages was lower after Brucella 2308 ΔOmp19 infection than after Brucella 2308 infection. In vivo, Brucella 2308 ΔOmp19 induced protective immune response in mice, and the splenic bacterial load of this deletion mutant was lower than that of Brucella 2308. In addition, the Brucella 2308 ΔOmp19 also promoted the fusion of Brucella-containing vacuoles and lysosomes, in macrophages. Therefore, Brucella 2308 ΔOmp19 reduced virulence compared with Brucella 2308 and activate the immune response of the host, and is a promising candidate for a live attenuated vaccine.

Keywords

• brucella
• omp19 gene
• homologous recombination
• viability
• intracellular survival