The arginine/ornithine binding protein ArgT plays an essential role in Brucella neotomae/Brucella melitensis to prevent intracellular killing and contribute to chronic persistence in the host.
Sushree Rekha Mallik, Kiranmai Joshi, Girish K Radhakrishnan
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引用次数: 0
Abstract
Brucella species are facultative intracellular bacterial pathogens that cause the contagious zoonotic disease, brucellosis. Brucella spp. infect a wide range of animals, including livestock, wild animals, and marine mammals. Compared with other invasive bacterial pathogens, partial information is available on the virulence factors of Brucella that enable them to survive in the host. Here, we performed transposon-based random mutagenesis of B. neotomae and identified the arginine/ornithine binding protein, ArgT, as one of the crucial virulence determinants of Brucella. Deleting ArgT from B. neotomae or B. melitensis resulted in its attenuation in macrophages, which was restored upon complementation with an ArgT expression plasmid. We observed that macrophages infected with ΔArgT-B. neotomae produced elevated levels of NO due to the inability of these mutants to deplete the host intracellular arginine through their importer. Furthermore, defective survival of ΔArgT B. neotomae and B. melitensis was observed in the infected mice, which correlated with enhanced NO production in the mice. Our studies revealed that ArgT plays a vital role in preventing intracellular killing and contributes to the chronic persistence of B. neotomae/B. melitensis in the host. This study highlights the essential role of arginine in clearing intracellular infections and the subversion of this host defense mechanism by intracellular pathogens for their chronic persistence.
期刊介绍:
Virulence is a fully open access peer-reviewed journal. All articles will (if accepted) be available for anyone to read anywhere, at any time immediately on publication.
Virulence is the first international peer-reviewed journal of its kind to focus exclusively on microbial pathogenicity, the infection process and host-pathogen interactions. To address the new infectious challenges, emerging infectious agents and antimicrobial resistance, there is a clear need for interdisciplinary research.