Inactivation of formyltransferase (wbkC) gene generates a Brucella abortus rough strain that is attenuated in macrophages and in mice

Lacerda, Thaís Lourdes Santos; Cardoso, Patrícia Gomes; Almeida, Leonardo Augusto de; Camargo, Ilana Lopes Baratella da Cunha; Afonso, Daniela A. F.; Trant, Cyntia Cardoso; Macedo, Gilson Costa; Campos, Eleonora; Cravero, Silvio; Salcedo, Suzana P.; Gorvel, Jean‐Pierre; Oliveira, Sérgio C.

doi:10.1016/j.vaccine.2010.06.023

Cited by 26 publications

(27 citation statements)

References 26 publications

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“…Our research group has previously demonstrated the virulence of the vaccine strains S19 and RB51 in IRF-1 KO mice. Only 70 to 80% of IRF-1 KO mice inoculated with S19 at 10 6 CFU survived the first 4 weeks after infection, while all mice inoculated with RB51 at 10 6 or 10 8 CFU survived the first 4 weeks (21,26). Our data suggest the following order of virulence in IRF-1 KO mice: the S2308 strain Ͼ ⌬omp19:: kan strain Ͼ ⌬mfp::kan strain.…”

Section: Resultsmentioning

confidence: 68%

“…Previous studies from our laboratory have identified genes related to survival and virulence in B. abortus (13,14,21,26). Here, we investigated the importance of the Brucella proteins Mfp and Omp19 in microbial pathogenesis by evaluating the persistence of the B. abortus gene replacement ⌬omp19::kan and ⌬mfp::kan mutant strains both intracellularly and in vivo.…”

Section: Discussionmentioning

confidence: 99%

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Mutant Brucella abortus Membrane Fusogenic Protein Induces Protection against Challenge Infection in Mice

et al. 2015

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f Brucella species can cause brucellosis, a zoonotic disease that causes serious livestock economic losses and represents a public health threat. The mechanism of virulence of Brucella spp. is not yet fully understood. Therefore, it is crucial to identify new molecules that serve as virulence factors to better understand this host-pathogen interplay. Here, we evaluated the role of the Brucella membrane fusogenic protein (Mfp) and outer membrane protein 19 (Omp19) in bacterial pathogenesis. In this study, we showed that B. abortus ⌬mfp::kan and ⌬omp19::kan deletion mutant strains have reduced persistence in vivo in C57BL/6 and interferon regulatory factor 1 (IRF-1) knockout (KO) mice. Additionally, 24 h after macrophage infection with a ⌬mfp::kan or ⌬omp19::kan strain expressing green fluorescent protein (GFP) approximately 80% or 65% of Brucella-containing vacuoles (BCVs) retained the late endosomal/lysosomal marker LAMP-1, respectively, whereas around 60% of BCVs containing wild-type S2308 were found in LAMP-1-negative compartments. B. abortus ⌬omp19::kan was attenuated in vivo but had a residual virulence in C57BL/6 and IRF-1 KO mice, whereas the ⌬mfp::kan strain had a lower virulence in these same mouse models. Furthermore, ⌬mfp::kan and ⌬omp19::kan strains were used as live vaccines. Challenge experiments revealed that in C57BL/6 and IRF-1 KO mice, the ⌬mfp::kan strain induced greater protection than the vaccine RB51 and protection similar that of vaccine S19. However, a ⌬omp19::kan strain induced protection similar to that of RB51. Thus, these results demonstrate that Brucella Mfp and Omp19 are critical for full bacterial virulence and that the ⌬mfp::kan mutant may serve as a potential vaccine candidate in future studies. Brucellosis is a chronic infectious disease caused by bacteria of the genus Brucella. This disease affects many species of animals, resulting in great economic losses, and is therefore an important bacterial zoonotic disease worldwide (1). The genus Brucella replicates inside trophoblasts, macrophages, and dendritic cells and colonizes the reticuloendothelial system and reproductive organs (2). Additionally, brucellosis is not only the major cause of abortion and infertility in animals but also a debilitating disease in humans (2-7).To overcome the immune system and establish a chronic infection, B. abortus utilizes diverse evasion mechanisms. This pathogen can penetrate host cells through lipid rafts (8). Once inside cells, the establishment of a persistent infection relies on the ability of the bacterium to form a Brucella-containing vacuole (BCV), which traffics from the endocytic compartment to the endoplasmic reticulum (ER), forming a replicative BCV. It is in this replicative BCV that the bacteria begin to multiply (8, 9).Extensive vaccination programs have been undertaken to prevent brucellosis in animals. Despite their availability, live vaccine strains have critical disadvantages (10). The main vaccines currently available for brucellosis are S19 and RB51 (derived from B. abortus)...

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Section: Resultsmentioning

confidence: 68%

Section: Discussionmentioning

confidence: 99%

Mutant Brucella abortus Membrane Fusogenic Protein Induces Protection against Challenge Infection in Mice

et al. 2015

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“…The level of systemic infection in murine brucellosis is detectable by enumerating the number of residual Brucella CFU in mouse spleens [19]. Thus, C57BL/6, IFN- γ −/− , and IL-12/ β 2-m −/− mice were infected with B. abortus virulent strain, and splenic CFU were counted at 1 and 3 weeks postinfection (Figure 1).…”

Section: Resultsmentioning

confidence: 99%

Host Susceptibility toBrucella abortusInfection Is More Pronounced in IFN-γknockout than IL-12/β2-Microglobulin Double-Deficient Mice

Brandão

Oliveira

Carvalho

et al. 2012

Clinical and Developmental Immunology

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Brucella abortus is a facultative intracellular bacterial pathogen that causes abortion in domestic animals and undulant fever in humans. IFN-γ, IL-12, and CD8+ T lymphocytes are important components of host immune responses against B. abortus. Herein, IFN-γ and IL-12/β2-microglobulin (β2-m) knockout mice were used to determine whether CD8+ T cells and IL-12-dependent IFN-γ deficiency would be more critical to control B. abortus infection compared to the lack of endogenous IFN-γ. At 1 week after infection, IFN-γ KO and IL-12/β2-m KO mice showed increased numbers of bacterial load in spleens; however, at 3 weeks postinfection (p.i.), only IFN-γ KO succumbed to Brucella. All IFN-γ KO had died at 16 days p.i. whereas death within the IL-12/β2-m KO group was delayed and occurred at 32 days until 47 days postinfection. Susceptibility of IL-12/β2-m KO animals to Brucella was associated to undetectable levels of IFN-γ in mouse splenocytes and inability of these cells to lyse Brucella-infected macrophages. However, the lack of endogenous IFN-γ was found to be more important to control brucellosis than CD8+ T cells and IL-12-dependent IFN-γ deficiencies.

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“…Notably, however, the loss of activity of a sugar N -formyltransferase in Brucella abortus results in a bacterial strain with attenuated pathogenicity. 13 …”

Section: Introductionmentioning

confidence: 99%

Biochemical Investigation of Rv3404c from Mycobacterium tuberculosis

et al. 2017

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The causative agent of tuberculosis, Mycobacterium tuberculosis, is a bacterium with a complex cell wall and a complicated life cycle. The genome of M. tuberculosis contains well over 4000 genes thought to encode proteins. One of these codes for a putative enzyme referred to as Rv3404c, which has attracted research attention as a potential virulence factor for over 12 years. Here we demonstrate that Rv3404c functions as a sugar N-formyltransferase that converts dTDP-4-amino-4,6-dideoxyglucose into dTDP-4-formamido-4,6-dideoxyglucose using N10- formyltetrahydrofolate as the carbon source. Kinetic analyses demonstrate that Rv3404c displays a significant catalytic efficiency of 1.1 × 104 M−1s−1. In addition, we report the X-ray structure of a ternary complex of Rv3404c solved in the presence of N5-formyltetrahydrofolate and dTDP-4-amino-4,6-dideoxyglucose. The final model of Rv3404c was refined to an overall R-factor of 16.8% at 1.6 Å resolution. The results described herein are especially intriguing given that there have been no published reports of N-formylated sugars associated with M. tuberculosis. The data thus provide a new avenue of research into this fascinating, yet deadly organism that apparently has been associated with human infection since ancient times.

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Inactivation of formyltransferase (wbkC) gene generates a Brucella abortus rough strain that is attenuated in macrophages and in mice

Cited by 26 publications

References 26 publications

Mutant Brucella abortus Membrane Fusogenic Protein Induces Protection against Challenge Infection in Mice

Mutant Brucella abortus Membrane Fusogenic Protein Induces Protection against Challenge Infection in Mice

Host Susceptibility toBrucella abortusInfection Is More Pronounced in IFN-γknockout than IL-12/β2-Microglobulin Double-Deficient Mice

Biochemical Investigation of Rv3404c from Mycobacterium tuberculosis

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