Brucella suppress STING expression via miR-24 to enhance infection.

Brucellosis, caused by a number of Brucella species, remains the most prevalent zoonotic disease worldwide. Brucella establish chronic infections within host macrophages despite triggering cytosolic innate immune sensors, including Stimulator of Interferon Genes (STING), which potentially limit infection. In this study, STING was required for control of chronic Brucella infection in vivo.

Hepatic and splenic immune response during acute vs. chronic Brucella melitensis infection using in situ microscopy.

Brucella melitensis is an intracellular bacteria causing disease in humans as an incidental host. The infection initiates as acute flu-like symptoms and may transform into a chronic cyclic infection. This cyclic infection may be partly due to the bacteria's ability to persist within antigen presenting cells and evade the CD8 + T cell response over long periods of time.

Cyclic Dinucleotides Trigger STING-Dependent Unfolded Protein Response That Favors Bacterial Replication.

is a facultative intracellular bacterium that causes brucellosis, a prevalent zoonosis that leads to abortion and infertility in cattle, and undulant fever, debilitating arthritis, endocarditis, and meningitis in humans. Signaling pathways triggered by involves stimulator of IFN genes (STING), which leads to production of type I IFNs. In this study, we evaluated the pathway linking the unfolded protein response (UPR) and the endoplasmic reticulum-resident transmembrane molecule STING, during infection.

Brucella Peptide Cross-Reactive Major Histocompatibility Complex Class I Presentation Activates SIINFEKL-Specific T Cell Receptor-Expressing T Cells.

spp. are intracellular pathogenic bacteria remarkable in their ability to escape immune surveillance and therefore inflict a state of chronic disease within the host. To enable further immune response studies, was engineered to express the well-characterized chicken ovalbumin (OVA).

Triggers a cGAS-Independent STING Pathway To Induce Host Protection That Involves Guanylate-Binding Proteins and Inflammasome Activation.

Immunity against microbes depends on recognition of pathogen-associated molecular patterns by innate receptors. Signaling pathways triggered by DNA involves TLR9, AIM2, and stimulator of IFN genes (STING). In this study, we observed by microarray analysis that several type I IFN-associated genes, such as IFN-β and guanylate-binding proteins (GBPs), are downregulated in STING knockout (KO) macrophages infected with or transfected with DNA.

The Bacterial Second Messenger Cyclic di-GMP Regulates Brucella Pathogenesis and Leads to Altered Host Immune Response.

Brucella species are facultative intracellular bacteria that cause brucellosis, a chronic debilitating disease significantly impacting global health and prosperity. Much remains to be learned about how Brucella spp. succeed in sabotaging immune host cells and how Brucella spp.

CD8+ T cell exhaustion, suppressed gamma interferon production, and delayed memory response induced by chronic Brucella melitensis infection.

Brucella melitensis is a well-adapted zoonotic pathogen considered a scourge of mankind since recorded history. In some cases, initial infection leads to chronic and reactivating brucellosis, incurring significant morbidity and economic loss. The mechanism by which B.

Studying host-pathogen interaction events in living mice visualized in real time using biophotonic imaging.

Despite progress in mouse models of bacterial pathogens, studies are often limited by evaluating infections in an individual organ or tissue or at a given time. Here we present a technique to engineer the pathogen, e.g.

Decreased in vivo virulence and altered gene expression by a Brucella melitensis light-sensing histidine kinase mutant.

Brucella species utilize diverse virulence factors. Previously, Brucella abortus light-sensing histidine kinase was identified as important for cellular infection. Here, we demonstrate that a Brucella melitensis LOV-HK (BM-LOV-HK) mutant strain has strikingly different gene expression than wild type.

Brucella induces an unfolded protein response via TcpB that supports intracellular replication in macrophages.

Brucella melitensis is a facultative intracellular bacterium that causes brucellosis, the most prevalent zoonosis worldwide. The Brucella intracellular replicative niche in macrophages and dendritic cells thwarts immune surveillance and complicates both therapy and vaccine development. Currently, host-pathogen interactions supporting Brucella replication are poorly understood.

Erythritol triggers expression of virulence traits in Brucella melitensis.

Erythritol is a four-carbon sugar preferentially utilized by Brucella spp. The presence of erythritol in the placentas of goats, cows, and pigs has been used to explain the localization of Brucella to these sites and the subsequent accumulation of large amounts of bacteria, eventually leading to abortion. Here we show that Brucella melitensis will also localize to an artificial site of erythritol within a mouse, providing a potential model system to study the pathogenesis of Brucella abortion.

Active evasion of CTL mediated killing and low quality responding CD8+ T cells contribute to persistence of brucellosis.

Brucellosis is a common zoonotic disease that remains endemic in many parts of the world. Dissecting the host immune response during this disease provides insight as to why brucellosis is often difficult to resolve. We used a Brucella epitope specific in vivo killing assay to investigate the ability of CD8+ T cells to kill targets treated with purified pathogenic protein.

Brucella melitensis cyclic di-GMP phosphodiesterase BpdA controls expression of flagellar genes.

Brucella melitensis encounters a variety of conditions and stimuli during its life cycle--including environmental growth, intracellular infection, and extracellular dissemination--which necessitates flexibility of bacterial signaling to promote virulence. Cyclic-di-GMP is a bacterial secondary signaling molecule that plays an important role in adaptation to changing environments and altering virulence in a number of bacteria. To investigate the role of cyclic-di-GMP in B.

Modulation of microtubule dynamics by a TIR domain protein from the intracellular pathogen Brucella melitensis.

TIR (Toll/interleukin-1 receptor) domain-containing proteins play a crucial role in innate immunity in eukaryotes. Brucella is a highly infectious intracellular bacterium that encodes a TIR domain protein (TcpB) to subvert host innate immune responses to establish a beneficial niche for pathogenesis. TcpB inhibits NF-κB (nuclear factor κB) activation and pro-inflammatory cytokine secretions mediated by TLR (Toll-like receptor) 2 and TLR4.

Antigen specific killing assay using CFSE labeled target cells.

Carboxyfluorescein diacetate succinimidyl ester (CFSE) can be used to easily and quickly label a cell population of interest for in vivo investigation. This labeling has classically been used to study proliferation and migration. In the method presented here, we have shortened the timeline after adoptive transfer to look at survival and killing of epitope specific CFSE labeled target cells.

Discordant Brucella melitensis antigens yield cognate CD8+ T cells in vivo.

Brucella spp. are intracellular bacteria that cause the most frequent zoonosis in the world. Although recent work has advanced the field of Brucella vaccine development, there remains no safe human vaccine.

Brucella TIR Domain-containing Protein Mimics Properties of the Toll-like Receptor Adaptor Protein TIRAP.

Toll-like receptors (TLRs) play essential roles in the activation of innate immune responses against microbial infections. TLRs and downstream adaptor molecules contain a conserved cytoplasmic TIR domain. TIRAP is a TIR domain-containing adaptor protein that recruits the signaling adaptor MyD88 to a subset of TLRs.

TBK1 does not play a role in the control of in vitro Burkholderia pseudomallei growth.

Burkholderia pseudomallei, the causative agent of melioidosis, is an important intracellular pathogen in tropical regions. TANK-binding kinase (TBK1), part of the pathway that induces transcription of Type I interferon genes, has been demonstrated to play an important role in controlling intracellular bacterial infections. To investigate the role of tbk1 in protecting against B.

Evaluation of recombinant invasive, non-pathogenic Eschericia coli as a vaccine vector against the intracellular pathogen, Brucella.

Background: There is no safe, effective human vaccine against brucellosis. Live attenuated Brucella strains are widely used to vaccinate animals. However these live Brucella vaccines can cause disease and are unsafe for humans.

Brucella: functional genomics and host-pathogen interactions.

Brucellosis is a zoonotic disease caused by a number of Brucella species and is characterized by chronic macrophage infection. However, genes that may contribute to intracellular survival of the Brucella species are not well studied. This review presents, first, genomic islands that are present or absent in various Brucella species that may help establish Brucella infection and survival strategies.

The role of integrase/recombinase xerD and monofunctional biosynthesis peptidoglycan transglycosylase genes in the pathogenicity of Brucella abortus infection in vitro and in vivo.

Brucella abortus clones identified previously using a green fluorescence protein reporter system after 4h macrophage infection provided insight regarding possible genes involved in early host-pathogen interaction. Among identified genes were an integrase/recombinase (xerD) gene involved in cell division, and a monofunctional biosynthesis peptidoglycan transglycosylase (mtgA) gene that catalyzes the final stages of the peptidoglycan membrane synthesis. Here, we evaluate the in vitro and in vivo survival of B.

Comparison of bovine leukemia virus (BLV) and CMV promoter-driven reporter gene expression in BLV-infected and non-infected cells.

BACKGROUND: Viral promoters are used in mammalian expression vectors because they generally have strong activity in a wide variety of cells of differing tissues and species. METHODS: The utility of the BLV LTR/promoter (BLVp) for use in mammalian expression vectors was investigated through direct comparison to the CMV promoter (CMVp). Promoter activity was measured using luciferase assays of cell lines from different tissues and species stably transduced with BLVp or CMVp driven luciferase vectors including D17, FLK, BL3.

Enhanced efficacy of DNA vaccines against an intracellular bacterial pathogen by genetic adjuvants.

After 200 years of practice, vaccinology has proved to be very effective in preventing infectious diseases. However, several human and animal pathogens exist for which vaccines need to be improved or simply have not yet been discovered. The era of molecular genetic has given a new breath for vaccine development with the achievement of the "Third Generation of Vaccines": the DNA vaccine.