Project description:A lot of attempts have been made to understand the immunopathological mechanisms of Brucella canis infection because of the importance of the disease in both public and clinical aspects. However, previous mechanisms are not still revealed. Therefore, in vitro models, which mimic to in vivo infection route using a canine epithelial cell, D17 cell, and a canine macrophage, DH82 cell, was used to solve the clues by analysis of transcriptomes in the cells. In this study, a co-culture model was constructed using the two cells, D17 and DH82 cell lines with trans-well plate. Also, a single cell culture system using DH82 was established. After stimulation of the cells in two different systems with B. canis, gene expressions in the macrophages of the two different system were analyzed by RNA-sequencing.
Project description:Leishmania (L.) infantum is the etiologic agent of visceral leishmaniasis (VL). In Brazil represents a serious public health problem. Studies have shown that regulation of immune response appears to depend on miRNAs. In canine VL due to cell immune suppression being determinant of disease progression, knowledge of miRNAs may be important for the pattern of change in immune response. Here, we suggest that post-transcriptional regulation, mediated by miRNAs, may play a role in immune response of dogs with VL.
Project description:Brucella abortus (B. abortus), an intracellular bacterium, is the causative agent of Brucellosis. This organism invades into macrophages and then survives through its abilities to modulate host cells functions. The biggest problem caused by B. abortus is that it prevents macrophage elimination and makes it difficult to remove B. abortus from the host body. Therefore, it is essential to identify the bacterial genes involved in virulence factor as a first step to understanding the bacterial pathogenicity and controlling Brucellosis. To identify these genes, B. abortus mutant strains were generated using transposon mutagenesis and transcriptomic profile during macrophage infection were analyzed. The gene expression level was analyzed using total RNA obtained from THP-1 cells infected with B. abortus wild type and mutant strains and cellular immunity during the infections were compared to wild type infected cell to identify the role of genes in B. abortus pathogenicity. Transcriptomic profiling showed that two mutant strains having disrupted genes related to 4-hydrobenzoate 3-monooxygenase (PHBH) of C1 strain and heme exporter protein cytochrome C (CcmC) of C10 strain, induced suppression of cytokine expression during infection in human macrophages. Conversely, two other mutant strains of exopolyphosphatase (PPX)of C27 and Peptidase M24 of C32 induced activation of cytokine expression in the THP-1 macrophage cells.
Project description:Gram-negative bacteria release nanovesicles, called outer membrane vesicles (OMVs), from their outer membrane. Proteomics has been used to determine their composition. OMVs contain proteins able to elicit an immune response, so they have been proposed as a model to develop acellular vaccines. In this study, OMVs of Brucella suis, B. ovis, B. canis, and B. neotomae were purified and analyzed by SDS-PAGE, transmission electron microscopy and liquid chromatography coupled to mass spectrometry to determine the pan-proteome of these vesicles. In addition, antigenic proteins were detected by western blot with anti-Brucella sera. The in silico analysis of the pan-proteome revealed many homologous proteins, such as Omp16, Omp25, Omp31, SodC, Omp2a, and BhuA. Proteins contained in the vesicles from different Brucella species were detected by anti-Brucella sera. The occurrence of previously described immunogenic proteins derived from OMVs supports the use of these vesicles as candidates to be evaluated as an acellular brucellosis vaccine.
Project description:Canine brucellosis, caused by Brucella canis, is a disease of dogs and represents a public health concern as it can be transmitted to humans. Canine brucellosis is on the rise in the United States and there is currently no vaccine for use in dogs. Mice have been extensively utilized to investigate host-pathogen interactions and vaccine candidates for smooth Brucella species and could serve a similar role for studying B. canis. However, comparatively little is known about B. canis infection in mice. The objective of this study was to characterize the kinetics of colonization and pathogenicity of B. canis in mice in order to evaluate the mouse as a model for studying this pathogen. C57BL/6 mice were inoculated intraperitoneally with 105, 107, or 109 CFU of Brucella canis RM6/66 and euthanized 1-, 2-, 4-, 6-, 9-, and 12-weeks post-inoculation. B. canis induced splenomegaly in mice infected with 109 CFU at 1- and 2 weeks post-inoculation while no gross lesions were observed in other dose groups. Infection at the two higher doses resulted in dose-dependent granulomatous hepatitis and histiocytic infiltration of the spleen and mesenteric lymph nodes by 1-2 weeks. B. canis was cultured from the liver, spleen, uterus, bone marrow, lung, and kidney in all groups with colonization declining at a slow but steady rate throughout the experiment. Clearance was achieved by 9 weeks 105 CFU group and by 12 weeks in the 107 CFU group, while B. canis persisted in the spleen until 12 weeks in the highest dose group. Although B. canis does not demonstrate significant replication in C57BL/6 mice, it has the ability to establish an infection, induce splenomegaly, and persist for several weeks in multiple organs. Moreover, 1 x 107 CFU appears to be a suitable challenge dose for investigating vaccine safety.