Project description:Brucellosis is an important zoonotic disease that causes great economic losses. Vaccine immunisation is the main strategy for the prevention and control of Brucellosis. Although live attenuated vaccines play important roles in the prevention of this disease, they also have several limitations, such as residual virulence and difficulty in the differentiation of immunisation and infection. We developed and evaluated a new bacteria ghost vaccine of Brucella abortus A19 by a new double inactivation method. The results showed that the bacterial ghost vaccine of Brucella represents a more safe and efficient vaccine for Brucellosis. We further characterised the antigenic components and signatures of the vaccine candidate A19BG. Here, we utilised a mass spectrometry-based label-free relative quantitative proteomics approach to investigate the global proteomics changes in A19BGs compared to its parental A19. The proteomic analysis identified 2014 proteins, 1116 of which were differentially expressed compared with those in A19. The common immunological proteins of OMPs (Bcsp31, Omp25, Omp10, Omp19, Omp28, and Omp2a), HSPs (DnaK, GroS, and GroL), and SodC were enriched in the proteome of A19BG. By protein micro array- based antibody profiling, significant differences were observed between A19BG and A19, and a number of signature immunogenic proteins were identified. Two of these proteins, BMEII0032 and BMEI0892, were confirmed to be differential diagnostic antigens for the A19BG vaccine candidate. In conclusion, using comparative proteomics and antibody profiling, protein components and signature antigens were identified for the ghost vaccine candidate A19BG, which are valuable for further developing the vaccine and its monitoring assays.
Project description:Gene expression analysis of wild-type and STING knock-out mouse bone marrow-derived macrophages (mBMDM) infected with Brucella abortus or transfected with Brucella abortus DNA. Genes whose expression are affected by Brucella abortus in a STING-dependent manner will be identified and signaling pathways regulated by STING will be elucidated.
Project description:We describe the isolation of sufficient Brucella abortus RNA from primary host cell environment using modified reported methods for RNA-seq analysis, and simultaneously characterize the transcriptional profiles of intracellular B. abortus and bone marrow-derived macrophages (BMM) from BALB/c mice at 24 h (replicative phase) post-infection.
Project description:MucR is one of the few transcriptional regulatory proteins that has been linked to Brucella pathogenesis. We used custom-made Affymetrix B. abortus strain 2308 derived GeneChips to copare the gene expression properties of wild type and isogenic mucR mutant cells.
Project description:Isogenic deletion and truncation of specific genes encoding RNases in Brucella abortus were analyzed for changes in gene expression. The main goal of this work is to determine the mRNAs that exhibit dysregulation when small regulatory RNAs (i.e., Bsr8) or RNases (i.e., RNaseE and RNaseJ) are invactivated in Brucella abortus. Small regulatory RNAs often control gene expression by binding directly to mRNAs to block translation or induce their degradation, and RNA from a deletion of one sRNA gene, bsr8, was analyzed to uncover the mRNAs that may be controlled by BsrB. RNases are enzymes that cleave RNAs during processing, turnover, and regulatory events, and RNaseE and RNaseJ appear to be important for B. abortus virulence. Therefore, to determine the mRNAs potentially targetd by these RNases, RNA from a strain harboring a RNaseE truncation and a strain carrying a deletion of rnaseJ were analyzed. In the end, the objective of this study was to gain insight into the regulatory patterns of specific B. abortus sRNAs and RNases.
Project description:Identification of host responses at the gene transcription level provides a molecular profile of the events that occur following infection. Brucella abortus is a facultative intracellular pathogen of macrophages that induces chronic infection in humans and domestic animals. Using microarray technology, the response of macrophages 4 hours following B. abortus infection was analyzed to identify early intracellular infection events that occur in macrophages. Of the more than 6,000 genes, we identified over 140 genes that were reproducibly differentially transcribed. First, an increase in the transcription of a number of pro-inflammatory cytokines and chemokines, such as TNF-α, IL-1β, IL-1α, and members of the SCY family of proteins, was evident that may constitute a general host recruitment of antibacterial defenses. Alternatively, Brucella may subvert newly arriving macrophages for additional intracellular infection. Second, transcription of receptors and cytokines associated with antigen presentation, e.g., MHC class II and IL-12p40, were not evident at this 4 hour period of infection. Third, Brucella inhibited transcription of various host genes involved in apoptosis, cell cycling, and intracellular vesicular trafficking. Identification of macrophage genes whose transcription was inhibited suggests that Brucella utilizes specific mechanisms to target certain cell pathways. In conclusion, these data suggest that B. abortus can alter macrophage pathways to recruit additional macrophages for future infection while simultaneously inhibiting apoptosis and innate immune mechanisms within the macrophage permitting intracellular survival of the bacterium. These results provide insights into the pathogenic strategies used by Brucella to survive long-term within a hostile environment. Keywords: Macrophage, intracellular pathogen, Brucella abortus, inflammatory immune response