Dataset Information

Helpful dirt: Why diphtheria toxoid vaccines may also protect against non-toxigenic Corynebacterium diphtheriae strains

ABSTRACT: Diphtheria toxoid vaccines are among the oldest and safest vaccines known. The basic principle of production is the inactivation of purified diphtheria toxin by formaldehyde cross-linking, which converts the potentially fatal toxin in a completely harmless protein aggregate, which is still immunogenic. Since in addition to diphtheria toxin also other proteins might be secreted by Corynebacterium diphtheriae, we assumed that diphtheria toxoid might not be the only component present in the vaccine. Therefore, we established a protocol to reverse formaldehyde cross-linking and carried out mass spectrometric analyses. Different secreted, membrane-associated and cytoplasmic proteins of C. diphtheriae were detected in several vaccine preparations from across the world. Western blot analyses indicated that these are immunogenic and may therefore support protection against C. diphtheriae. Furthermore, we could show that the vaccines also induce antibodies directed against diphtheria toxin secreted by Corynebacterium ulcerans, an emerging pathogen evoking diphtheria-like illness and skin infections.

INSTRUMENT(S): LTQ Orbitrap Elite

ORGANISM(S): Clostridium Tetani E88 Corynebacterium Diphtheriae Nctc 13129

TISSUE(S): Cell Culture

SUBMITTER: Jens Möller

LAB HEAD: Andreas Burkovski

PROVIDER: PXD009289 | Pride | 2019-04-17

REPOSITORIES: Pride

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More than a Toxin: Protein Inventory of Clostridium tetani Toxoid Vaccines.

Möller Jens J Kraner Max Edmund ME Burkovski Andreas A

Proteomes 20190416 2

Clostridium tetani is the etiological agent of tetanus, a life-threatening bacterial infection. The most efficient protection strategy against tetanus is a vaccination with the C. tetani neurotoxin, which is inactivated by formaldehyde-crosslinking. Since we assumed that besides the tetanus toxin, other proteins of C. tetani may also be present in toxoid preparations, we analyzed commercially available vaccines from different countries in respect to their protein content usi ...[more]

PMID: 30988272

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Project description:We assessed changes in gene expression in response to iron availability for the human pathogen Corynebacterium diphtheriae. Expression profiles of wild-type C. diphtheriae strain 1737 grown in semi-defined metal-poor media (mPGT) in iron-limiting (0.5 µM iron chloride supplementation) and iron-replete (10 µM supplementation) conditions were compared; the expression profiles of wild-type C. diphtheriae strain 1737 during growth in iron-replete conditions was also compared against an isogenic ΔdtxR mutant grown in iron-replete conditions. Three biological replicates were prepared by isolating total RNA from mid-logarithmic growth cultures and ten genes (dip0169, dip0415, dip1061, dip1062, dip2330, dip1486, dip0173, dip1252, dip1866, and dip0281) were quantified by real-time PCR to validate the array results. Corynebacterium diphtheriae is the causative agent of the severe respiratory disease, diphtheria. Diphtheria Toxin (DT), encoded by the tox gene, is the potent exotoxin secreted by C. diphtheriae responsible for much of the morbidity and mortality of diphtheria. Expression of the tox gene is regulated by the Diphtheria Toxin Repressor (DtxR) and iron. In addition to the regulation of toxin expression, DtxR functions as a global iron-dependent regulatory factor that mediates iron homeostasis in C. diphtheriae. While numerous genes regulated by DtxR and iron are known, a genome-wide study of both the iron and DtxR regulons is lacking in C. diphtheriae. Here, we report novel iron- and DtxR-regulated genes revealed by a comprehensive transcriptomic analysis. Not all identified genes appear to be repressed by iron and DtxR; some genes were found to be induced by iron in a DtxR-dependent manner, a mechanism of regulation not previously described in C. diphtheriae. Using a prediction algorithm (MEME) and electrophoretic mobility shift assays, we verified DtxR binding to sequences upstream of several newly identified genes. Furthermore, we characterized expression of ferritin (ftn) and catalase (cat), which are both induced by iron, but differentially affected by DtxR. We identified three DtxR binding sites in the ftn promoter, while analysis of the cat promoter establishes a role for DtxR in cat expression and suggests complex regulation by additional regulators. Collectively, these results expand our knowledge on the function of DtxR and the diverse roles of this regulatory protein in controlling gene expression.

Project description:Background: The human pathogen Corynebacterium diphtheriae is the causative agent of the disease diphtheria. In the 1990s a large diphtheria outbreak in Eastern Europe was caused by the strain C. diphtheriae NCTC 13129. Although the genome was sequenced several years ago, not much is known about the transcriptome. Our aim was to use RNA Sequencing to close this knowledge gap and gain insights into the transcriptional landscape of C. diphtheriae. Results: We applied two different RNA Sequencing techniques, one to retrieve 5' ends of primary transcripts and one to obtain full length transcripts, to gain insights into various features of the C. diphtheriae NCTC 13129 transcriptome. By examining the data we identified 1,657 transcription start sites (TSS) of which 1,229 were assigned to genes and 428 to putative novel transcripts. By using the TSS data SigA promotor regions and their motifs could be analyzed in detail, revealing a well conserved –10 but unconserved –35 motif, respectively. Furthermore with the TSS data in hand 5' UTR lengths were explored. The observed 5' UTRs range from leaderless, which make up 20 % of all genes, up to over 450 bp long leaders, which may harbor regulatory functions. The C. diphtheriae transcriptome consists of 470 operons which are further divided into 167 sub-operon structures. In addition we discovered that the deletion of the iron sensing transcription regulator DtxR, which also controls expression of diphtheria toxin (DT), has a strong influence on general gene expression. Nearly 15 % of the genome is differentially expressed, indicating that DtxR might have other functions next to regulation of iron metabolism and DT. Furthermore we shed light on the transcriptional landscape of the DT encoding gene tox and present evidence for an additional TSS and three tox antisense RNAs, which might reveal new ways of transcriptional regulation. Conclusions: This study presents extensive insights into the transcriptome of C. diphtheriae and provides a basis for future studies regarding transcriptional regulators, gene characterization and the tox gene in particular.

Project description:We assessed changes in gene expression in response to zinc availability for the human pathogen Corynebacterium diphtheriae. Expression profiles of wild-type C. diphtheriae strain 1737 grown in semi-defined metal-poor media (mPGT) without and with 5 µM zinc chloride supplementation were compared; the expression profile of wild-type C. diphtheriae strain 1737 in zinc-replete conditions was also compared against an isogenic Δzur mutant grown in zinc-replete conditions. Three biological replicates were prepared by isolating total RNA from mid-logarithmic growth cultures and eleven genes (dip0013, dip0093, dip0173, dip0438, dip1087, dip1486, dip1724, dip2114, dip2128, dip2162, and dip2325) were assessed by real-time PCR to validate the array results. (Abstract) Corynebacterium diphtheriae is a Gram-positive bacterial pathogen and the causative agent of diphtheria, a severe disease of the upper respiratory tract of humans. Factors required for C. diphtheriae to survive in the human host are not well defined, but likely include the acquisition of essential metals such as zinc. In C. diphtheriae, zinc-responsive global gene regulation is controlled by the Zinc Uptake Regulator (Zur), a member of the Fur-family of transcriptional regulators. In this study, we use transcriptomics to identify zinc-regulated genes in C. diphtheriae by comparing gene expression of a wild-type strain grown without and with zinc supplementation. Zur-regulated genes were identified by comparing wild-type gene expression with that of an isogenic zur mutant. We observed zinc repression of several putative surface proteins, the heme efflux system hrtBA, various ABC transporters, and the non-ribosomal peptide synthetase/polyketide synthase cluster sidAB. Furthermore, increased gene expression in response to zinc was observed for the alcohol dehydrogenase, adhA. Zinc and Zur regulation were confirmed for several genes by complementing the zur deletion and subsequent qPCR analysis. We used MEME to predict Zur binding sites within the promoter regions of zinc- and Zur-regulated genes, and verified Zur binding by electrophoretic mobility shift assays. Additionally, we characterized cztA (dip1101), which encodes a putative cobalt/zinc/cadmium efflux family protein. Deletion of cztA results in increased sensitivity to zinc, but not to cobalt or cadmium. This study advances our knowledge of changes to Zur-dependent global gene expression in response to zinc in C. diphtheriae. The identification of zinc-regulated ABC transporters herein will facilitate future studies to characterize zinc transport in C. diphtheriae.

Project description:We assessed changes in gene expression in response to manganese availability for the human pathogen Corynebacterium diphtheriae. Total RNA was harvested from wild-type C. diphtheriae strain 1737 and an isogenic ΔmntR (dip0619) grown in semi-defined metal-limited media (mPGT) without or with 5 µM manganese chloride supplementation. Three biological replicates were prepared and five genes were assessed by real-time PCR to validate the array results: dip0124, dip0169, dip0615, dip1923, and dip2261. (Abstract) Corynebacterium diphtheriae is the causative agent of a severe respiratory disease in humans. The bacterial systems required for infection are poorly understood, but the acquisition of metals such as manganese (Mn) are likely critical for host colonization. MntR is a Mn-dependent transcriptional regulator in C. diphtheriae and was previously shown to repress the expression of the mntABCD genes, which encode an ABC metal transporter. However, other targets of Mn and MntR regulation in C. diphtheriae have not been identified. In this study, we use comparisons between the gene expression profiles of wild-type C. diphtheriae strain 1737 grown without or with Mn supplementation and comparisons of gene expression between wild-type and an mntR mutant to characterize the C. diphtheriae Mn and MntR regulon. MntR was observed to both repress and induce the expression of various target genes in a Mn-dependent manner. Genes induced by MntR include the Mn-superoxide dismutase, sodA, and the putative ABC transporter locus, iutABCD. DNA binding studies showed that MntR interacts at the promoter regions for several genes identified in the expression study, and a 17-bp consensus MntR DNA binding site was identified. We found that an mntR mutant displayed increased sensitivity to Mn and Cd that could be alleviated by the additional deletion of the mntA-D transport locus, providing evidence that the MntABCD transporter functions as a Mn uptake system in C. diphtheriae. The findings in this study further our understanding of metal uptake systems and global metal regulatory networks in this important human pathogen.

Project description:Many modern vaccines use defined adjuvants to stimulate the innate immune system and shape the adaptive immune response. The exact nature of these innate signals and whether immune differentiation can originate within the periphery is not known. In the present study we used an ovine lymphatic cannulation model to characterise the cellular and transcriptomic profile of the afferent lymph following injection of a liposomal vaccine formulation incorporating diphtheria toxoid and the innate stimulator poly (I:C) over a 78 h period. The response to this vaccine featured an early activation of broad proinflammatory pathways (e.g. TLR signalling and inflammasome pathways) and the transient recruitment of granulocytes into the lymph. At 24hrs a more monocytic cellular profile arose coinciding with a transition to a specific antiviral response characterised by the up-regulation of genes associated with the receptors typical for the viral mimic, poly (I:C) (e.g. TLR3, RIG-I and MDA5). At the latest time points the up-regulation of IL-17A and IL-17F suggested that Th17 cells may participate in the earliest adaptive response to this vaccine. Together these data provide the most comprehensive picture of the cellular and molecular mechanisms that link the periphery to the draining lymph node following vaccination and indicate that the immune response is capable of specialising within the periphery. This study employed an ovine model of pseudoafferent lymphatic cannulation (see de Veer et al. 2010, Vaccine) to characterise the innate immune response within the afferent lymph to vaccination with liposomes+poly (I:C)+ diptheria toxoid. The sheep used in this study had both their pre-femoral lymph nodes removed at 1 year of age. Approximately 1 year after the lymph node removal, a second surgery was performed to insert a 0.96_0.58mm heparin-coated polyvinyl chloride cannula into the pseudoafferent (previous efferent) lymphatic duct of both sides. At least seven days were allowed for healing to occur after surgery before vaccinations were administered and experimental lymph samples were collected. Handling of animals and experimental procedures were all approved by the Monash University Animal Ethics Committee in accordance with the relevant licensing agreement. Vaccinations were injected subcutaneously in the area drained by the prefemoral lymph node. Afferent lymphatic samples were collected prior to vaccination as a control (PRE) and at 4-6, 26-28, 51-53 and 76-78 hours post vaccination with liposomes+poly (I:C)+ diptheria toxoid. Lymphocytes were removed from the afferent lymph using immunomagnetic separation. Next-generation sequencing was performed on RNA derived from the remaining innate immune cells. Samples from three sheep were used at all time points except 4-6 and 26-28 hours, where only two samples yielded sufficient RNA for sequencing.

			Action	DRS
	Brazil.msf	Msf
	Brazil.raw	Raw
	Brazilrepl.2.msf	Msf
	Brazilrepl.2.raw	Raw
	Bulgaria.msf	Msf

Dataset Information

Helpful dirt: Why diphtheria toxoid vaccines may also protect against non-toxigenic Corynebacterium diphtheriae strains

Dataset's files

Publications

More than a Toxin: Protein Inventory of <i>Clostridium tetani</i> Toxoid Vaccines.

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