Project description:Oral cholera vaccines (OCVs) have become important components of strategies for cholera control, but the demand for OCVs has outstripped the supply2–4. There is a need for new cholera control measures for the one billion people living in cholera endemic regions5. The use of orally delivered single-domain antibodies has been proposed as a potential approach for the control of gastrointestinal pathogens6. Here, we describe the development of an orally deliverable bivalent VHH construct (BL3.2) that binds to the B-subunit of cholera toxin (CTXB). The epitope of CTXB for binding molecule BL3.2 was mapped by Hydrogen Deuterium Exchange HDX
Project description:The present study used microarray approach to identify the genomewide response to cholera toxin in the presence of nitrate. Considering that fact that the possibility of the existence of multiple Gα genes/proteins in plants has not been conclusively ruled out, analysis of the genomewide impact of RGA1 mutation in rice and GPA1 mutation in Arabidopsis reveal only those genes that are under their direct control. On the other hand, assuming that all those different Gα subunits in any given plant are regulated by cholera toxin, analysis of the genomwide response to cholera toxin could capture the entire G-protein responsive transcriptome, beyond what can be revealed by the mutant approach. This could reveal even those genes that respond to other, as yet unidentified Gα subunits, as well as reveal some genes that are non-specifically regulated by cholera toxin, independent of any G-proteins.
Project description:T cells were separately isolated from MLN and PP from two naive mice, and T cells binding to a cholera toxin B subunit specific MHC II tetramer from mice orally immunized with cholera toxin 7 days or boosted 5 days with a second dose of cholera toxin. Cells were purified using flow cytometric cell sorting and 3´ (n=5) or 5´ (n=5) libraries were constructed using the 10X workflow. From 5´libraries TCR libraries were also constructed and sequenced.
Project description:Pandemic and endemic strains of Vibrio cholerae arise from toxigenic conversion by the CTXφ bacteriophage, a process by which CTXφ infects non-toxigenic strains of V. cholerae. CTXφ encodes the cholera toxin, an enterotoxin responsible for the watery diarrhea associated with cholera infections. Despite the critical role of CTXφ during infections, signals that affect CTXφ-driven toxigenic conversion or expression of the CTXφ-encoded cholera toxin remain poorly characterized, particularly in the context of the gut mucosa. Here, we identify mucin polymers as potent regulators of CTXφ-driven pathogenicity in V. cholerae. Our results indicate that mucin-associated O-glycans block toxigenic conversion by CTXφ and suppress the expression of CTXφ-related virulence factors, including the toxin co-regulated pilus and cholera toxin, by interfering with the TcpP/ToxR/ToxT virulence pathway. By synthesizing individual mucin glycan structures de novo, we identify the Core 2 motif as the critical structure governing this virulence attenuation. Overall, our results highlight a novel mechanism by which mucins and their associated O-glycan structures affect CTXφ-mediated evolution and pathogenicity of V. cholerae, underscoring the potential regulatory power housed within mucus.
Project description:Understanding gene expression by bacteria during the actual course of human infection may provide important insights into microbial pathogenesis. In this study, we evaluated the transcriptional profile of Vibrio cholerae, the causative agent of cholera, in clinical specimens from cholera patients. We collected samples of human stool and vomitus that were positive by dark-field microscopy for abundant vibrios and used a microarray to compare gene expression in organisms recovered directly from the early and late stages of human infection. Our results reveal that V. cholerae gene expression within the human host environment differs from patterns defined in in vitro models of pathogenesis. tcpA, the major subunit of the essential V. cholerae colonization factor, was significantly more highly expressed in early compared with late infection; however, the genes encoding cholera toxin were not highly expressed in either phase of human infection. Furthermore, expression of the virulence regulators, toxRS and tcpPH, was uncoupled. Interestingly, the pattern of gene expression indicates that the human upper intestine may be a uniquely suitable environment for the transfer of genetic elements that are important in the evolution of pathogenic strains of V. cholerae. These findings provide a more detailed assessment of the transcriptome of V. cholerae in the human host than previous studies of organisms in stool alone and have implications for cholera control and the design of improved vaccines. Keywords: comparative gene expression analysis
Project description:Bone marrow-derived dendritic cells from C57BL/6 mice were treated with 1 ug/ml cholera toxin, 10 uM forskolin or control medium for 2 h.