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Vij S, Thakur R, Singh RP, Kumar R, Pathania P, Gupta V, Suri CR, Rishi P. Dual immunization with CdtB protein and flagellin epitope offers augmented protection against enteric fever in mice. Life Sci 2023; 334:122216. [PMID: 37918629 DOI: 10.1016/j.lfs.2023.122216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 10/17/2023] [Accepted: 10/25/2023] [Indexed: 11/04/2023]
Abstract
AIMS Present study has explored the protective response of dual immunization using two different antigenic entities (i.e. flagellin epitope and cytolethal distending toxin subunit B (CdtB) protein) against lethal challenge of typhoidal serovars in a murine model. MAIN METHODS In-vitro immunogenicity of flagellin epitope-BSA conjugate and CdtB protein was confirmed using Indirect ELISA of typhoid positive patients' sera. Further, both entities were administered intraperitoneally in mice individually or in combination, followed by lethal challenge of typhoidal Salmonellae. Various parameters were analysed such as bacterial burden, mice survival, histopathological analysis, cytokine analysis and immunophenotyping. Serum samples obtained from the immunized mice were used for passive immunization studies, wherein mice survival and mechanism of action of the generated antibodies was studied. KEY FINDINGS Active immunization studies using the combination of both entities demonstrated improved mice survival after lethal challenge with typhoidal Salmonellae, reduced bacterial burden in organs, expression of immunophenotypic markers in splenocytes and restored tissue histoarchitecture. When used in combination, the effective doses of both the candidates reduced which may be attributed to multiprong approach used by the immune system to recognize Salmonella. Passive immunization studies further determined the protective efficacy of generated antibodies by different mechanisms such as complement mediated bactericidal action, swarming inhibition and increased phagocytic uptake. SIGNIFICANCE Present study is the first phase of the proof-of-concept which may prove to be beneficial in developing an effective bi-functional vaccine candidate to render protection against both Vi-positive as well as Vi-negative Salmonella strains.
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Affiliation(s)
- Shania Vij
- Department of Microbiology, Panjab University, Chandigarh 160014, India.
| | - Reena Thakur
- Department of Microbiology, Panjab University, Chandigarh 160014, India
| | | | - Rashmi Kumar
- CSIR-Institute of Microbial Technology (IMTech), Chandigarh 160036, India
| | - Preeti Pathania
- CSIR-Institute of Microbial Technology (IMTech), Chandigarh 160036, India
| | - Varsha Gupta
- Department of Microbiology, Government Medical College and Hospital (GMCH), Sector 32, Chandigarh 160030, India
| | - Chander Raman Suri
- CSIR-Institute of Microbial Technology (IMTech), Chandigarh 160036, India
| | - Praveen Rishi
- Department of Microbiology, Panjab University, Chandigarh 160014, India.
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Igiri BE, Okoduwa SIR, Munirat SA, Otu-Bassey IB, Bashir A, Onyiyioza OM, Enang IA, Okoduwa UJ. Diversity in Enteric Fever Diagnostic Protocols and Recommendation for Composite Reference Standard. IRANIAN JOURNAL OF MEDICAL MICROBIOLOGY 2023; 17:22-38. [DOI: 10.30699/ijmm.17.1.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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3
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Hefele L, Black AP, Van Tan T, Tri Minh N, Duc Hoang N, Virachith S, Muller CP, Hübschen JM, Russell P, Bartholdson Scott J, Ngoc Minh CN, Thieu Nga TV, Baker S. An age-stratified serosurvey against purified Salmonella enterica serovar Typhi antigens in the Lao People´s Democratic Republic. PLoS Negl Trop Dis 2021; 15:e0010017. [PMID: 34898620 PMCID: PMC8700045 DOI: 10.1371/journal.pntd.0010017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 12/23/2021] [Accepted: 11/22/2021] [Indexed: 11/18/2022] Open
Abstract
The epidemiology of typhoid fever in Lao People`s Democratic Republic is poorly defined. Estimating the burden of typhoid fever in endemic countries is complex due to the cost and limitations of population-based surveillance; serological approaches may be a more cost-effective alternative. ELISAs were performed on 937 serum samples (317 children and 620 adults) from across Lao PDR to measure IgG antibody titers against Vi polysaccharide and the experimental protein antigens, CdtB and HlyE. We measured the significance of the differences between antibody titers in adults and children and fitted models to assess the relationship between age and antibody titers. The median IgG titres of both anti-HylE and CdtB were significantly higher in children compared to adults (anti-HylE; 351.7 ELISA Units (EU) vs 198.1 EU, respectively; p<0.0001 and anti-CdtB; 52.6 vs 12.9 EU; p<0.0001). Conversely, the median anti-Vi IgG titer was significantly higher in adults than children (11.3 vs 3.0 U/ml; p<0.0001). A non-linear trend line fitted to the anti-CdtB and anti-HlyE IgG data identified a peak in antibody concentration in children <5 years of age. We identified elevated titers of anti-HlyE and anti-CdtB IgG in the serum of children residing in Lao PDR in comparison to adults. These antigens are associated with seroconversion after typhoid fever and may be a superior measure of disease burden than anti-Vi IgG. This approach is scalable and may be developed to assess the burden of typhoid fever in countries where the disease may be endemic, and evidence is required for the introduction of typhoid vaccines. Typhoid fever is a serious bloodstream infection caused by the bacterium Salmonella Typhi. Estimating the burden of typhoid fever is complex due to the limitations, cost, and scalability of current diagnostic surveillance methods. The detection of specific antibody responses against the organism may be a more sustainable manner of measuring exposure and disease burden in endemic location. We measured antibody (IgG) in 937 serum samples (317 children and 620 adults) from across the Lao People`s Democratic Republic against a polysaccharide (Vi) and two experimental protein antigens, CdtB and HlyE, that may more appropriate markers of disease exposure. We measured the significance of the differences between antibody titers in adults and children and fitted models to assess the relationship between age and antibody titers. The median IgG titres against HylE and CdtB were significantly higher in children than adults. Conversely, the median IgG titres against Vi was significantly higher in adults than children. We identified a significant association between a peak in IgG titres against CdtB and HlyE in children aged under 5 years. These data are indicative of high level of typhoid fever exposure in children under 5 years of age in Lao PDR and we surmise that IgG titres against HylE and CdtB may be a superior measure of typhoid disease burden than IgG titres against Vi. Our approach is scalable and can be further validated to assess the burden of typhoid fever in countries where the disease may be endemic, and evidence is required for the introduction of typhoid vaccines.
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Affiliation(s)
- Lisa Hefele
- Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Grand-Duchy of Luxembourg
- Lao-Lux Laboratory, Institut Pasteur du Laos, Vientiane, Lao People’s Democratic Republic
| | - Antony P. Black
- Lao-Lux Laboratory, Institut Pasteur du Laos, Vientiane, Lao People’s Democratic Republic
| | - Trinh Van Tan
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Nguyen Tri Minh
- University of Natural Sciences, Ho Chi Minh City Vietnam
- Vietnam National University, Ho Chi Minh City, Vietnam
| | - Nguyen Duc Hoang
- University of Natural Sciences, Ho Chi Minh City Vietnam
- Vietnam National University, Ho Chi Minh City, Vietnam
| | - Siriphone Virachith
- Lao-Lux Laboratory, Institut Pasteur du Laos, Vientiane, Lao People’s Democratic Republic
| | - Claude P. Muller
- Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Grand-Duchy of Luxembourg
| | - Judith M. Hübschen
- Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Grand-Duchy of Luxembourg
| | - Paula Russell
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Josefin Bartholdson Scott
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Chau Nguyen Ngoc Minh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Tran Vu Thieu Nga
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Stephen Baker
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
- * E-mail:
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4
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Performance of Immunodiagnostic Tests for Typhoid Fever: A Systematic Review and Meta-Analysis. Pathogens 2021; 10:pathogens10091184. [PMID: 34578216 PMCID: PMC8467574 DOI: 10.3390/pathogens10091184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 09/01/2021] [Accepted: 09/07/2021] [Indexed: 12/23/2022] Open
Abstract
Typhoid fever, also known as typhoid, is a life-threatening bacterial infection that remains a global health concern. The infection is associated with a significant morbidity and mortality rate, resulting in an urgent need for specific and rapid detection tests to aid prevention and management of the disease. The present review aims to assess the specificity and sensitivity of the available literature on the immunodiagnostics of typhoid fever. A literature search was conducted using three databases (PubMed, ProQuest and Scopus) and manual searches through the references of identified full texts to retrieve relevant literature published between 1 January 2011 and 31 December 2020. Of the 577 studies identified in our search, 12 were included in further analysis. Lipopolysaccharides (LPS) and hemolysin E (HlyE) were the most frequently studied antigens. The specimens examined in these studies included serum and saliva. Using blood culture as the gold standard, anti-LPS IgA gave the highest sensitivity of 96% (95% CI: 93–99) and specificity of 96% (95% CI: 93–99) for distinguishing between typhoid cases and healthy controls, whereas the combination of anti-LPS and anti-flagellin total IgGAM gave the highest sensitivity of 93% (95% CI: 86–99) and specificity of 95% (95% CI: 89–100) for distinguishing typhoid cases and other febrile infections. A comparably high sensitivity of 92% (95% CI: 86–98) and specificity of 89% (95% CI: 78–100) were shown in testing based on detection of the combination of anti-LPS (IgA and IgM) and anti-HlyE IgG as well as a slightly lower sensitivity of 91% (95% CI: 74–100) in the case of anti-50kDa IgA. Anti-50kDa IgM had the lowest sensitivity of 36% (95% CI: 6–65) against both healthy and febrile controls. The development of a rapid diagnostic test targeting antibodies against lipopolysaccharides combined with flagellin appeared to be a suitable approach for the rapid detection test of typhoid fever. Saliva is added benefit for rapid typhoid diagnosis since it is less invasive. As a result, further studies could be done to develop additional approaches for adopting such samples.
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5
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Enteric Fever Diagnosis: Current Challenges and Future Directions. Pathogens 2021; 10:pathogens10040410. [PMID: 33915749 PMCID: PMC8065732 DOI: 10.3390/pathogens10040410] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 03/23/2021] [Accepted: 03/27/2021] [Indexed: 12/21/2022] Open
Abstract
Enteric fever is a life-threatening systemic febrile disease caused by Salmonella enterica serovars Typhi and Paratyphi (S. Typhi and S. Paratyphi). Unfortunately, the burden of the disease remains high primarily due to the global spread of various drug-resistant Salmonella strains despite continuous advancement in the field. An accurate diagnosis is critical for effective control of the disease. However, enteric fever diagnosis based on clinical presentations is challenging due to overlapping symptoms with other febrile illnesses that are also prevalent in endemic areas. Current laboratory tests display suboptimal sensitivity and specificity, and no diagnostic methods are available for identifying asymptomatic carriers. Several research programs have employed systemic approaches to identify more specific biomarkers for early detection and asymptomatic carrier detection. This review discusses the pros and cons of currently available diagnostic tests for enteric fever, the advancement of research toward improved diagnostic tests, and the challenges of discovering new ideal biomarkers and tests.
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6
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Lee S, Yang YA, Milano SK, Nguyen T, Ahn C, Sim JH, Thompson AJ, Hillpot EC, Yoo G, Paulson JC, Song J. Salmonella Typhoid Toxin PltB Subunit and Its Non-typhoidal Salmonella Ortholog Confer Differential Host Adaptation and Virulence. Cell Host Microbe 2020; 27:937-949.e6. [PMID: 32396840 DOI: 10.1016/j.chom.2020.04.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 02/18/2020] [Accepted: 04/03/2020] [Indexed: 01/19/2023]
Abstract
Typhoidal and non-typhoidal Salmonelleae (NTS) cause typhoid fever and gastroenteritis, respectively, in humans. Salmonella typhoid toxin contributes to typhoid disease progression and chronic infection, but little is known about the role of its NTS ortholog. We found that typhoid toxin and its NTS ortholog induce different clinical presentations. The PltB subunit of each toxin exhibits different glycan-binding preferences that correlate with glycan expression profiles of host cells targeted by each bacterium at the primary infection or intoxication sites. Through co-crystal structures of PltB subunits bound to specific glycan receptor moieties, we show that they induce markedly different glycan-binding preferences and virulence outcomes. Furthermore, immunization with the NTS S. Javiana or its toxin offers cross-reactive protection against lethal-dose typhoid toxin challenge. Cumulatively, these results offer insights into the evolution of host adaptations in Salmonella AB toxins, their cell and tissue tropisms, and the design for improved typhoid vaccines and therapeutics.
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Affiliation(s)
- Sohyoung Lee
- Department of Microbiology and Immunology, Cornell University College of Veterinary Medicine, Ithaca, NY 14853, USA
| | - Yi-An Yang
- Department of Microbiology and Immunology, Cornell University College of Veterinary Medicine, Ithaca, NY 14853, USA
| | - Shawn K Milano
- Department of Molecular Medicine, Cornell University College of Veterinary Medicine, Ithaca, NY 14853, USA
| | - Tri Nguyen
- Department of Microbiology and Immunology, Cornell University College of Veterinary Medicine, Ithaca, NY 14853, USA
| | - Changhwan Ahn
- Department of Microbiology and Immunology, Cornell University College of Veterinary Medicine, Ithaca, NY 14853, USA
| | - Ji Hyun Sim
- Department of Microbiology and Immunology, Cornell University College of Veterinary Medicine, Ithaca, NY 14853, USA
| | - Andrew J Thompson
- Department of Molecular Medicine, the Scripps Research Institute, La Jolla, CA 92121, USA
| | - Eric C Hillpot
- Department of Molecular Medicine, Cornell University College of Veterinary Medicine, Ithaca, NY 14853, USA
| | - Gyeongshik Yoo
- Department of Microbiology and Immunology, Cornell University College of Veterinary Medicine, Ithaca, NY 14853, USA
| | - James C Paulson
- Department of Molecular Medicine, the Scripps Research Institute, La Jolla, CA 92121, USA
| | - Jeongmin Song
- Department of Microbiology and Immunology, Cornell University College of Veterinary Medicine, Ithaca, NY 14853, USA.
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7
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Nguyen T, Lee S, Yang YA, Ahn C, Sim JH, Kei TG, Barnard KN, Yu H, Millano SK, Chen X, Parrish CR, Song J. The role of 9-O-acetylated glycan receptor moieties in the typhoid toxin binding and intoxication. PLoS Pathog 2020; 16:e1008336. [PMID: 32084237 PMCID: PMC7055914 DOI: 10.1371/journal.ppat.1008336] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 03/04/2020] [Accepted: 01/20/2020] [Indexed: 12/20/2022] Open
Abstract
Typhoid toxin is an A2B5 toxin secreted from Salmonella Typhi-infected cells during human infection and is suggested to contribute to typhoid disease progression and the establishment of chronic infection. To deliver the enzymatic 'A' subunits of the toxin to the site of action in host cells, the receptor-binding 'B' subunit PltB binds to the trisaccharide glycan receptor moieties terminated in N-acetylneuraminic acid (Neu5Ac) that is α2-3 or α2-6 linked to the underlying disaccharide, galactose (Gal) and N-acetylglucosamine (GlcNAc). Neu5Ac is present in both unmodified and modified forms, with 9-O-acetylated Neu5Ac being the most common modification in humans. Here we show that host cells associated with typhoid toxin-mediated clinical signs express both unmodified and 9-O-acetylated glycan receptor moieties. We found that PltB binds to 9-O-acetylated α2-3 glycan receptor moieties with a markedly increased affinity, while the binding affinity to 9-O-acetylated α2-6 glycans is only slightly higher, as compared to the affinities of PltB to the unmodified counterparts, respectively. We also present X-ray co-crystal structures of PltB bound to related glycan moieties, which supports the different effects of 9-O-acetylated α2-3 and α2-6 glycan receptor moieties on the toxin binding. Lastly, we demonstrate that the cells exclusively expressing unmodified glycan receptor moieties are less susceptible to typhoid toxin than the cells expressing 9-O-acetylated counterparts, although typhoid toxin intoxicates both cells. These results reveal a fine-tuning mechanism of a bacterial toxin that exploits specific chemical modifications of its glycan receptor moieties for virulence and provide useful insights into the development of therapeutics against typhoid fever.
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Affiliation(s)
- Tri Nguyen
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Sohyoung Lee
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Yi-An Yang
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Changhwan Ahn
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Ji Hyun Sim
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Tiffany G. Kei
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Karen N. Barnard
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Hai Yu
- Department of Chemistry, University of California, Davis, California, United States of America
| | - Shawn K. Millano
- Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Xi Chen
- Department of Chemistry, University of California, Davis, California, United States of America
| | - Colin R. Parrish
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Jeongmin Song
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
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8
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Thakur R, Pathania P, Kaur N, Joshi V, Kondepudi KK, Suri CR, Rishi P. Prophylactic potential of cytolethal distending toxin B (CdtB) subunit of typhoid toxin against Typhoid fever. Sci Rep 2019; 9:18404. [PMID: 31804525 PMCID: PMC6895121 DOI: 10.1038/s41598-019-54690-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 11/18/2019] [Indexed: 02/04/2023] Open
Abstract
Typhoid fever caused by Salmonella enterica serovar Typhi (S.Typhi) continues to be a major problem, especially in developing countries. Due to the rapid emergence of multi-drug-resistant (MDR) strains, which limits the efficacy of conventional antibiotics as well as problems associated with the existing vaccines, efforts are being made to develop effective prophylactic agents. CdtB subunit of typhoid toxin was selected for assessing its vaccine potential due to its high conservation throughout the Typhi strains. In-vitro assessment of DNase activity of cloned and purified CdtB protein showed a significant decrease in the band intensity of DNA. The measure of metabolic activity and morphological alterations assessed using different cell lines in the presence of CdtB protein showed no significant signs of toxicity. These observations were further strengthened by cell cycle analysis, assessed by flow cytometry. Keeping these observations in mind, the immunoprotective potential of CdtB was assessed using S.Typhi induced mouse peritonitis model. A significant titer of IgG antibodies (>128000) against CdtB protein was recorded in the immunized mice by enzyme-linked immunosorbent assay (ELISA), which was also validated by immunoblotting. Active immunization with the protein protected 75% mice against a lethal dose of S.Typhi Ty2. The data indicated a significant (up to 5 log) reduction in the bacterial load in the spleen and liver of immunized-infected mice compared to control (unimmunized-infected) mice which might have resulted in the modulation of histoarchitecture of spleen and liver and the levels of cytokines (IL-6, TNF-α and IL-10) production; thereby indicating the effectiveness of the subunit. The observations deduced from the study give the proof of concept of immunogenic potential of protein. However, further studies involving the immunoreactivity of CdtB with the statistically significant number of sera samples obtained from the human patients would be helpful in establishing the relevance of CdtB protein in humans and for making the strategies to develop it as an effective vaccine candidate.
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Affiliation(s)
- Reena Thakur
- Department of Microbiology, Panjab University, Chandigarh, India
| | - Preeti Pathania
- Department of Microbiology, Panjab University, Chandigarh, India
| | - Navneet Kaur
- Department of Microbiology, Panjab University, Chandigarh, India
| | - Vattan Joshi
- Department of Microbiology, Panjab University, Chandigarh, India
| | | | | | - Praveen Rishi
- Department of Microbiology, Panjab University, Chandigarh, India.
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9
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Gibani MM, Jones E, Barton A, Jin C, Meek J, Camara S, Galal U, Heinz E, Rosenberg-Hasson Y, Obermoser G, Jones C, Campbell D, Black C, Thomaides-Brears H, Darlow C, Dold C, Silva-Reyes L, Blackwell L, Lara-Tejero M, Jiao X, Stack G, Blohmke CJ, Hill J, Angus B, Dougan G, Galán J, Pollard AJ. Investigation of the role of typhoid toxin in acute typhoid fever in a human challenge model. Nat Med 2019; 25:1082-1088. [PMID: 31270506 PMCID: PMC6892374 DOI: 10.1038/s41591-019-0505-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Accepted: 05/30/2019] [Indexed: 11/09/2022]
Abstract
Salmonella Typhi is a human host-restricted pathogen that is responsible for typhoid fever in approximately 10.9 million people annually1. The typhoid toxin is postulated to have a central role in disease pathogenesis, the establishment of chronic infection and human host restriction2–6. However, its precise role in typhoid disease in humans is not fully defined. We studied the role of typhoid toxin in acute infection using a randomized, double-blind S. Typhi human challenge model7. Forty healthy volunteers were randomized (1:1) to oral challenge with 104 colony-forming units of wild-type or an isogenic typhoid toxin deletion mutant (TN) of S. Typhi. We observed no significant difference in the rate of typhoid infection (fever ≥38 °C for ≥12 h and/or S. Typhi bacteremia) between participants challenged with wild-type or TN S. Typhi (15 out of 21 (71%) versus 15 out of 19 (79%); P = 0.58). The duration of bacteremia was significantly longer in participants challenged with the TN strain compared with wild-type (47.6 hours (28.9–97.0) versus 30.3(3.6–49.4); P ≤ 0.001). The clinical syndrome was otherwise indistinguishable between wild-type and TN groups. These data suggest that the typhoid toxin is not required for infection and the development of early typhoid fever symptoms within the context of a human challenge model. Further clinical data are required to assess the role of typhoid toxin in severe disease or the establishment of bacterial carriage. Typhoid toxin is not essential for the pathogenesis of typhoid fever in healthy humans challenged with Salmonella Typhi.
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Affiliation(s)
- Malick M Gibani
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK. .,Department of Medicine, Imperial College London, London, UK.
| | - Elizabeth Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Amber Barton
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Celina Jin
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Juliette Meek
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Susana Camara
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Ushma Galal
- Nuffield Department of Primary Care Health Sciences, Clinical Trials Unit, University of Oxford, Oxford, UK
| | - Eva Heinz
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK.,Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Yael Rosenberg-Hasson
- Human Immune Monitoring Center, Institute for Immunity, Transplantation and Infection, Stanford University, Stanford, CA, USA
| | - Gerlinde Obermoser
- Human Immune Monitoring Center, Institute for Immunity, Transplantation and Infection, Stanford University, Stanford, CA, USA
| | - Claire Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Danielle Campbell
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Charlotte Black
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Helena Thomaides-Brears
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Christopher Darlow
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Christina Dold
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Laura Silva-Reyes
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Luke Blackwell
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Maria Lara-Tejero
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Xuyao Jiao
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Gabrielle Stack
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Christoph J Blohmke
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Jennifer Hill
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Brian Angus
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Gordon Dougan
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK.,Department of Medicine, University of Cambridge, Hinxton, UK
| | - Jorge Galán
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
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