| 1. |
- Cervin, Jakob, et al.
(författare)
-
GM1 ganglioside-independent intoxication by Cholera toxin
- 2018
-
Ingår i: PLoS Pathogens. - : Public Library of Science (PLoS). - 1553-7366 .- 1553-7374. ; 14:2
-
Tidskriftsartikel (refereegranskat)abstract
- Cholera toxin (CT) enters and intoxicates host cells after binding cell surface receptors via its B subunit (CTB). We have recently shown that in addition to the previously described binding partner ganglioside GM1, CTB binds to fucosylated proteins. Using flow cytometric analysis of primary human jejunal epithelial cells and granulocytes, we now show that CTB binding correlates with expression of the fucosylated Lewis X (LeX) glycan. This binding is competitively blocked by fucosylated oligosaccharides and fucose-binding lectins. CTB binds the LeX glycan in vitro when this moiety is linked to proteins but not to ceramides, and this binding can be blocked by mAb to LeX. Inhibition of glycosphingolipid synthesis or sialylation in GM1-deficient C6 rat glioma cells results in sensitization to CT-mediated intoxication. Finally, CT gavage produces an intact diarrheal response in knockout mice lacking GM1 even after additional reduction of glycosphingolipids. Hence our results show that CT can induce toxicity in the absence of GM1 and support a role for host glycoproteins in CT intoxication. These findings open up new avenues for therapies to block CT action and for design of detoxified enterotoxin-based adjuvants.
|
|
| 2. |
- Ahmed, Tanvir, 1970, et al.
(författare)
-
CD4+ T-cell responses to an oral inactivated cholera vaccine in young children in a cholera endemic country and the enhancing effect of zinc supplementation.
- 2009
-
Ingår i: Vaccine. - : Elsevier BV. - 1873-2518 .- 0264-410X. ; 28:2, s. 422-9
-
Tidskriftsartikel (refereegranskat)abstract
- Immunization of young children with the oral inactivated whole cell cholera vaccine Dukoral((R)) containing recombinant cholera toxin B subunit (CTB) induces antibody responses which can be further enhanced by zinc supplementation. We have investigated if immunization with the cholera vaccine induces specific T-cell responses in young children and also whether zinc supplementation influences these responses. Bangladeshi children (10-18 months old) received vaccine alone, vaccine together with zinc supplementation or only zinc. T-cell blast formation indicating a proliferative response was analyzed by the flow cytometric assay of cell-mediated immune response in activated whole blood (FASCIA) and cytokines were measured by ELISA. Stronger T-cell responses were detected if a modified CTB molecule (mCTB) with reduced binding to GM1 ganglioside was used for cell stimulation compared to normal CTB. After vaccination, CD4+ T cells responded to mCTB with significantly increased blast formation (P<0.01) and IFN-gamma production (P<0.05) compared to before vaccination. No responses to mCTB were detected in children receiving zinc alone (P>0.05). The IFN-gamma production was significantly higher (P<0.01) but the blast formation comparable (P>0.05) in children receiving zinc plus vaccine compared to in children receiving vaccine alone. The vibriocidal antibody responses induced by the vaccine were also significantly higher in children receiving zinc supplementation (P<0.001). Our results thus show that oral cholera vaccination induces a Th1 T-cell response in young children, and that the IFN-gamma as well as the vibriocidal antibody responses can be enhanced by zinc supplementation.
|
|
| 3. |
|
|
| 4. |
- Benktander, John, et al.
(författare)
-
The Repertoire of Glycosphingolipids Recognized by Vibrio cholerae
- 2013
-
Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 8:1
-
Tidskriftsartikel (refereegranskat)abstract
- The binding of cholera toxin to the ganglioside GM1 as the initial step in the process leading to diarrhea is nowadays textbook knowledge. In contrast, the knowledge about the mechanisms for attachment of Vibrio cholerae bacterial cells to the intestinal epithelium is limited. In order to clarify this issue, a large number of glycosphingolipid mixtures were screened for binding of El Tor V. cholerae. Several specific interactions with minor complex non-acid glycosphingolipids were thereby detected. After isolation of binding-active glycosphingolipids, characterization by mass spectrometry and proton NMR, and comparative binding studies, three distinct glycosphingolipid binding patterns were defined. Firstly, V. cholerae bound to complex lacto/neolacto glycosphingolipids with the GlcNAcβ3Galβ4GlcNAc sequence as the minimal binding epitope. Secondly, glycosphingolipids with a terminal Galα3Galα3Gal moiety were recognized, and the third specificity was the binding to lactosylceramide and related compounds. V. cholerae binding to lacto/neolacto glycosphingolipids, and to the other classes of binding-active compounds, remained after deletion of the chitin binding protein GbpA. Thus, the binding of V. cholerae to chitin and to lacto/neolacto containing glycosphingolipids represents two separate binding specificities.
|
|
| 5. |
- Chowdhury, F., et al.
(författare)
-
A phase I/II study to evaluate safety, tolerability and immunogenicity of Hillchol®, an inactivated single Hikojima strain based oral cholera vaccine, in a sequentially age descending population in Bangladesh
- 2021
-
Ingår i: Vaccine. - : Elsevier BV. - 0264-410X. ; 39:32, s. 4450-4457
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The World Health Organization (WHO) recommends the use of oral cholera vaccines (OCVs) as part of an integrated control program, both in highly endemic settings and during cholera epidemics. The available and internationally recommended WHO-prequalified OCVs (Dukoral, Shanchol, Euvichol) contain multiple heat and formalin-killed V. cholerae strains of Inaba and Ogawa serotypes. MSD Wellcome Trust Hilleman Laboratories Pvt. Ltd. in technical collaboration with University of Gothenburg, Sweden has developed a new single strain OCV, Hillchol. This vaccine consists of formaldehyde-inactivated whole cell El Tor V. cholerae O1 bacteria engineered into the Hikojima serotype for stable expression of both the Ogawa (AB) and Inaba (AC) LPS antigens on the bacterial surface. We evaluated the safety and immunogenicity of this novel and potentially much less expensive OCV in comparison with Shanchol. Methods: We conducted a randomized, non-inferiority, age-descending clinical trial of OCV (Hillchol vs. Shanchol) in the Mirpur area of Dhaka city from July 2016 to May 2017. This study was carried out in three different age cohorts (1–<5, 5–17 and ≥18 years old). Two doses of vaccine were given at 14 days intervals to 560 healthy participants. Findings: No serious adverse events were reported. There were no significant differences in the rates of adverse events between the test vaccine (Hillchol) and the comparator (Shanchol) group. Serum vibriocidal antibody responses in all age groups combined were comparable for all the O1 Ogawa (59% vs. 67%; 90% CI of difference: −14.55, −0.84) and Inaba (70% vs. 71%; 90% CI of difference: −7.24, 5.77) serotypes, showing that the Hillchol vaccine was non-inferior to Shanchol. This new vaccine was also non-inferior to Shanchol in the different age strata. Conclusion: The safety and immunogenicity profile of the new OCV Hillchol is comparable to Shanchol in persons residing in a cholera-endemic setting. ClinicalTrials.gov number: NCT02823899. © 2021
|
|
| 6. |
- Davitt, C. J. H., et al.
(författare)
-
Alpha-galactosylceramide enhances mucosal immunity to oral whole-cell cholera vaccines
- 2019
-
Ingår i: Mucosal Immunology. - : Elsevier BV. - 1933-0219. ; 12, s. 1055-1064
-
Tidskriftsartikel (refereegranskat)abstract
- Cholera is a severe diarrheal disease caused by the bacterium Vibrio cholerae (V. cholerae) that results in 3–4 million cases globally with 100,000–150,000 deaths reported annually. Mostly confined to developing nations, current strategies to control the spread of cholera include the provision of safe drinking water and improved sanitation and hygiene, ideally in conjunction with oral vaccination. However, difficulties associated with the costs and logistics of these strategies have hampered their widespread implementation. Specific challenges pertaining to oral cholera vaccines (OCVs) include a lack of safe and effective adjuvants to further enhance gut immune responses, the complex and costly multicomponent vaccine manufacturing, limitations of conventional liquid formulation and the lack of an integrated delivery platform. Herein we describe the use of the orally active adjuvant α-Galactosylceramide (α-GalCer) to strongly enhance intestinal bacterium- and toxin-specific IgA responses to the OCV, Dukoral ® in C57BL/6 and BALB/c mice. We further demonstrate the mucosal immunogenicity of a novel multi-antigen, single-component whole-cell killed V. cholerae strain and the enhancement of its immunogenicity by adding α-GalCer. Finally, we report that combining these components and recombinant cholera toxin B subunit in the SmPill ® minisphere delivery system induced strong intestinal and systemic antigen-specific antibody responses. © 2019, The Author(s).
|
|
| 7. |
- George-Chandy, Annie, 1969, et al.
(författare)
-
Oral tolerance induction by mucosal administration of cholera toxin B-coupled antigen involves T-cell proliferation in vivo and is not affected by depletion of CD25+ T cells.
- 2006
-
Ingår i: Immunology. - : Wiley. - 0019-2805 .- 1365-2567. ; 118:3, s. 311-20
-
Tidskriftsartikel (refereegranskat)abstract
- Oral administration of antigens coupled to the B subunit of the cholera toxin (CTB) can dramatically reduce the amount of antigen needed for tolerance induction and has been used in several animal models to suppress conditions where the immune system overreacts to foreign and self-antigens. In this study, the cellular events following oral administration of CTB-coupled antigen was investigated. As a model system, limited numbers of CSFE-labelled cells from influenza haemagglutinin peptide (HApep) T-cell transgenic mice were transferred to wild type mice and the mice were then given CTB-coupled HApep orally. The inductive events of CTB-induced tolerance was characterized by extensive proliferation of HApep-specific T cells in the mesenteric lymph nodes (MLNs) and in the spleen. The proliferating cells up-regulated the gut homing molecule alpha4beta7 and down-regulated the high endothelial venule binding molecule L-selectin. Addition of the whole cholera toxin (CT) to CTB-HApep showed a similar pattern as CTB-HApep feeding, with antigen-specific proliferation in the MLN and spleen and expression of alpha4beta7 on the proliferating cells. However, addition of CT to CTB-HApep, produced a stronger and faster proliferative response and abrogated CTB-HA mediated oral tolerance. Feeding of CTB-HApep expanded CD25+ cells in the MLNs. CTB-induced oral tolerance could, however, not be explained by CD25+ dependent regulatory activity, as oral administration of CTB-HApep to mice depleted of CD25+ cells still gave rise to systemic tolerance. Thus, several mechanisms might co-orchestrate the systemic tolerance seen in response to feeding with CTB-coupled antigen.
|
|
| 8. |
- Holmgren, Jan, 1944, et al.
(författare)
-
Mucosal adjuvants and anti-infection and anti-immunopathology vaccines based on cholera toxin, cholera toxin B subunit and CpG DNA
- 2005
-
Ingår i: Immunology Letters. - : Elsevier. - 0165-2478 .- 1879-0542. ; 97:2, s. 181-8
-
Tidskriftsartikel (refereegranskat)abstract
- Mucosal immunisation may be used both to protect the mucosal surfaces against infections and as a means for immunological treatment of peripheral immunopathological disorders through the induction of systemic antigen-specific tolerance ('oral tolerance'). The development of mucosal vaccines, whether for prevention of infectious diseases or for oral tolerance immunotherapy, requires efficient antigen delivery and adjuvant systems that can help to present the appropriate vaccine or immunotherapy antigens to the mucosal immune system. The most potent (but also toxic) mucosal adjuvants are cholera toxin (CT) and the closely related Escherichia coli heat-labile enterotoxin (LT), and much effort and significant progress have been made recently to generate toxicologically acceptable derivatives of these toxins with retained adjuvant activity. Among these are the non-toxic, recombinantly produced cholera toxin B-subunit (CTB). CTB is a specific protective antigen component of a widely registered oral cholera vaccine as well as a promising vector for either giving rise to mucosal anti-infective immunity or for inducing peripheral anti-inflammatory tolerance to chemically or genetically linked foreign antigens administered mucosally. CT and CTB have also recently been used as combined vectors and adjuvants for markedly promoting ex vivo dendritic cell (DC) vaccination with different antigens and also steering the immune response to the in vivo-reinfused DCs towards either broad Th1 + Th2 + CTL immunity (CT) or Th2 or tolerance (CTB). Another type of mucosal adjuvants is represented by bacterial DNA or synthetic oligodeoxynucleotides containing CpG-motifs, which especially when linked to CTB have been found to effectively stimulate both innate and adaptive mucosal immune responses. The properties and clinical potential of these different classes of adjuvants are being discussed. © 2004 Elsevier B.V. All rights reserved.
|
|
| 9. |
- Holmgren, Jan, 1944, et al.
(författare)
-
Preclinical immunogenicity and protective efficacy of an oral Helicobacter pylori inactivated whole cell vaccine and multiple mutant cholera toxin: A novel and non-toxic mucosal adjuvant
- 2018
-
Ingår i: Vaccine. - : Elsevier BV. - 0264-410X. ; 36:41, s. 6223-6230
-
Tidskriftsartikel (refereegranskat)abstract
- Mucosal vaccines against Helicobacter pylori consisting of either whole cell bacteria or recombinant antigens can induce immune protection against challenge in mice only when co-administrated with a strong mucosal adjuvant such as cholera toxin (CT) or Escherichia coli heat labile enterotoxin (LT). The strong enterotoxicity of these adjuvants however preclude their use in human vaccines. The recently developed multiple mutant CT (mmCT) is a strong, yet practically non-toxic novel mucosal adjuvant which here was admixed with a formalin-inactivated H. pylori whole cell vaccine (WCV) as a potential vaccine candidate against H. pylori infection. We report that intragastric immunizations with H. pylori WCV together with mmCT, similar to immunization with WCV together with CT, resulted in 50-125-fold reduction in colonization of H. pylori in the stomach of mice associated with rises in both serum IgG and intestinal-mucosal IgA anti-H. pylori antibody responses and strong T cell and IFN gamma and IL-17A cytokine responses. Data presented in this study also supports that the proposed vaccine can be grown in a bioreactor and would be effective against infection caused by a multitude of pathogenic H. pylori strains isolated from patients from various continents. The results warrant immunization studies in humans to evaluate the safety, immunogenicity and efficacy of the proposed H. pylori WCV and mmCT. (C) 2018 Published by Elsevier Ltd.
|
|
| 10. |
|
|
