1
|
Rim S, Vedøy OB, Brønstad I, McCann A, Meyer K, Steinsland H, Hanevik K. Inflammation, the kynurenines, and mucosal injury during human experimental enterotoxigenic Escherichia coli infection. Med Microbiol Immunol 2024; 213:2. [PMID: 38430452 PMCID: PMC10908629 DOI: 10.1007/s00430-024-00786-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 12/29/2023] [Indexed: 03/03/2024]
Abstract
Enterotoxigenic Escherichia coli (ETEC) is an important cause of diarrhea in children and travelers, especially in low- and middle-income countries. ETEC is a non-invasive gut pathogen colonizing the small intestinal wall before secreting diarrhea-inducing enterotoxins. We sought to investigate the impact of ETEC infection on local and systemic host defenses by examining plasma markers of inflammation and mucosal injury as well as kynurenine pathway metabolites. Plasma samples from 21 volunteers experimentally infected with ETEC were collected before and 1, 2, 3, and 7 days after ingesting the ETEC dose, and grouped based on the level of intestinal ETEC proliferation: 14 volunteers experienced substantial proliferation (SP) and 7 had low proliferation (LP). Plasma markers of inflammation, kynurenine pathway metabolites, and related cofactors (vitamins B2 and B6) were quantified using targeted mass spectrometry, whereas ELISA was used to quantify the mucosal injury markers, regenerating islet-derived protein 3A (Reg3a), and intestinal fatty acid-binding protein 2 (iFABP). We observed increased concentrations of plasma C-reactive protein (CRP), serum amyloid A (SAA), neopterin, kynurenine/tryptophan ratio (KTR), and Reg3a in the SP group following dose ingestion. Vitamin B6 forms, pyridoxal 5'-phosphate and pyridoxal, decreased over time in the SP group. CRP, SAA, and pyridoxic acid ratio correlated with ETEC proliferation levels. The changes following experimental ETEC infection indicate that ETEC, despite causing a non-invasive infection, induces systemic inflammation and mucosal injury when proliferating substantially, even in cases without diarrhea. It is conceivable that ETEC infections, especially when repeated, contribute to negative health impacts on children in ETEC endemic areas.
Collapse
Affiliation(s)
- Sehee Rim
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway.
| | - Oda Barth Vedøy
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Ingeborg Brønstad
- National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, Bergen, Norway
- Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | | | | | - Hans Steinsland
- Department of Global Public Health and Primary Care, Faculty of Medicine, Centre for Intervention Science in Maternal and Child Health, Centre for International Health, University of Bergen, Bergen, Norway
- Department of Biomedicine, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Kurt Hanevik
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
- Department of Medicine, National Center for Tropical Infectious Diseases, Haukeland University Hospital, Bergen, Norway
| |
Collapse
|
2
|
Xu C, Fu F, She Y, Yang D, Peng K, Lin Y, Xu C. Development of a new candidate vaccine against piglet diarrhea caused by Escherichia coli. Open Life Sci 2023; 18:20220804. [PMID: 38196514 PMCID: PMC10775170 DOI: 10.1515/biol-2022-0804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 11/02/2023] [Accepted: 11/14/2023] [Indexed: 01/11/2024] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) is an important type of pathogenic bacteria that causes diarrhea in humans and young livestock. The pathogen has a high morbidity and mortality rate, resulting in significant economic losses in the pig industry. To effectively prevent piglet diarrhea, we developed a new tetravalent genetically engineered vaccine that specifically targets ETEC. To eliminate the natural toxin activity of ST1 enterotoxin and enhance the preventive effect of the vaccine, the mutated ST 1, K88ac, K99, and LT B genes were amplified by PCR and site-specific mutation techniques. The recombinant strain BL21(DE3)(pXKK3SL) was constructed and achieved high expression. Animal experiments showed that the inactivated vaccine had eliminated the natural toxin activity of ST1. The immune protection test demonstrated that the inclusion body and inactivated vaccine exhibited a positive immune effect. The protection rates of the inclusion body group and inactivated vaccine group were 96 and 98%, respectively, when challenged with 1 minimum lethal dose, indicating that the constructed K88ac-K99-3ST1-LTB vaccine achieved a strong immune effect. Additionally, the minimum immune doses for mice and pregnant sows were determined to be 0.2 and 2 mL, respectively. This study suggests that the novel K88ac-K99-3ST1-LTB vaccine has a wide immune spectrum and can prevent diarrhea caused by ETEC through enterotoxin and fimbrial pathways. The aforementioned research demonstrates that the K88ac-K99-3ST1-LTB vaccine offers a new genetically engineered vaccine that shows potential for preventing diarrhea in newborn piglets.
Collapse
Affiliation(s)
- Chongli Xu
- College of Medical Technology, Chongqing Medical and Pharmaceutical College, 82 Daxuecheng Road, Chongqing401331, PR China
| | - Fengyang Fu
- College of Medical Technology, Chongqing Medical and Pharmaceutical College, 82 Daxuecheng Road, Chongqing401331, PR China
| | - Yuhan She
- College of Medical Technology, Chongqing Medical and Pharmaceutical College, 82 Daxuecheng Road, Chongqing401331, PR China
| | - Danni Yang
- College of Medical Technology, Chongqing Medical and Pharmaceutical College, 82 Daxuecheng Road, Chongqing401331, PR China
| | - Kun Peng
- College of Medical Technology, Chongqing Medical and Pharmaceutical College, 82 Daxuecheng Road, Chongqing401331, PR China
| | - Yimin Lin
- Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, Chongqing400030, PR China
| | - ChongBo Xu
- School of Biology and Agriculture, Shaoguan University, Shaoguan512005, PR China
| |
Collapse
|
3
|
Akhtar M, Basher SR, Nizam NN, Hossain L, Bhuiyan TR, Qadri F, Lundgren A. T helper cell responses in adult diarrheal patients following natural infection with enterotoxigenic Escherichia coli are primarily of the Th17 type. Front Immunol 2023; 14:1220130. [PMID: 37809062 PMCID: PMC10552643 DOI: 10.3389/fimmu.2023.1220130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 08/31/2023] [Indexed: 10/10/2023] Open
Abstract
Background Infection with enterotoxigenic Escherichia coli (ETEC) gives rise to IgA antibodies against both the heat labile toxin (LT) and colonization factors (CFs), which are considered to synergistically protect against ETEC diarrhea. Since the development of ETEC-specific long lived plasma cells and memory B cells is likely to be dependent on T helper (Th) cells, we investigated if natural ETEC diarrhea elicits ETEC-specific Th cells and their relation to IgA responses. Methods Th cell subsets were analyzed in adult Bangladeshi patients hospitalized due to ETEC diarrhea by flow cytometric analysis of peripheral blood mononuclear cells (PBMCs) isolated from blood collected day 2, 7, 30 and 90 after hospitalization as well as in healthy controls. The LT- and CF-specific Th responses were determined by analysis of IL-17A and IFN-γ in antigen stimulated PBMC cultures using ELISA. ETEC-specific IgA secreted by circulating antibody secreting cells (plasmablasts) were analyzed by using the antibodies in lymphocyte supernatants (ALS) ELISA-based method and plasma IgA was also measured by ELISA. Results ETEC patients mounted significant ALS and plasma IgA responses against LTB and CFs on day 7 after hospitalization. ETEC patients had significantly elevated proportions of memory Th cells with a Th17 phenotype (CCR6+CXCR3-) in blood compared to controls, while frequencies of Th1 (CCR6-CXCR3+) or Th2 (CCR6-CXCR3-) cells were not increased. Antigen stimulation of PBMCs revealed IL-17A responses to LT, most clearly observed after stimulation with double mutant heat labile toxin (dmLT), but also with LT B subunit (LTB), and to CS6 in samples from patients with LT+ or CS6+ ETEC bacteria. Some individuals also mounted IFN-γ responses to dmLT and LTB. Levels of LTB specific IgA antibodies in ALS, but not plasma samples correlated with both IL-17A (r=0.5, p=0.02) and IFN-γ (r=0.6, p=0.01) responses to dmLT. Conclusions Our results show that ETEC diarrhea induces T cell responses, which are predominantly of the Th17 type. The correlations between IL-17A and IFN-g and intestine-derived plasmablast responses support that Th responses may contribute to the development of protective IgA responses against ETEC infection. These observations provide important insights into T cell responses that need to be considered in the evaluation of advanced ETEC vaccine candidates.
Collapse
Affiliation(s)
- Marjahan Akhtar
- Infectious Diseases Divison, icddr, b (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Salima Raiyan Basher
- Infectious Diseases Divison, icddr, b (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Nuder Nower Nizam
- Infectious Diseases Divison, icddr, b (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Lazina Hossain
- Infectious Diseases Divison, icddr, b (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Taufiqur Rahman Bhuiyan
- Infectious Diseases Divison, icddr, b (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Firdausi Qadri
- Infectious Diseases Divison, icddr, b (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Anna Lundgren
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
- Department of Clinical Immunology and Transfusion Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden
| |
Collapse
|
4
|
Brønstad I, von Volkmann HL, Sakkestad ST, Steinsland H, Hanevik K. Reduced Plasma Guanylin Levels Following Enterotoxigenic Escherichia coli-Induced Diarrhea. Microorganisms 2023; 11:1997. [PMID: 37630557 PMCID: PMC10458898 DOI: 10.3390/microorganisms11081997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 07/20/2023] [Accepted: 08/01/2023] [Indexed: 08/27/2023] Open
Abstract
The intestinal peptide hormones guanylin (GN) and uroguanylin (UGN) interact with the epithelial cell receptor guanylate cyclase C to regulate fluid homeostasis. Some enterotoxigenic Escherichia coli (ETEC) produce heat-stable enterotoxin (ST), which induces diarrhea by mimicking GN and UGN. Plasma concentrations of prohormones of GN (proGN) and UGN (proUGN) are reportedly decreased during chronic diarrheal diseases. Here we investigate whether prohormone concentrations also drop during acute diarrhea caused by ST-producing ETEC strains TW10722 and TW11681. Twenty-one volunteers were experimentally infected with ETEC. Blood (n = 21) and urine (n = 9) specimens were obtained immediately before and 1, 2, 3, and 7 days after ETEC ingestion. Concentrations of proGN and proUGN were measured by ELISA. Urine electrolyte concentrations were measured by photometry and mass spectrometry. Ten volunteers developed diarrhea (D group), and eleven did not (ND group). In the D group, plasma proGN, but not proUGN, concentrations were substantially reduced on days 2 and 3, coinciding with one day after diarrhea onset. No changes were seen in the ND group. ETEC diarrhea also seemed to affect diuresis, the zinc/creatinine ratio, and sodium and chloride secretion levels in urine. ETEC-induced diarrhea causes a reduction in plasma proGN and could potentially be a useful marker for intestinal isotonic fluid loss.
Collapse
Affiliation(s)
- Ingeborg Brønstad
- National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, 5021 Bergen, Norway; (I.B.); (H.L.v.V.)
- Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway
| | - Hilde Løland von Volkmann
- National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, 5021 Bergen, Norway; (I.B.); (H.L.v.V.)
- Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway
| | - Sunniva Todnem Sakkestad
- Department of Clinical Science, University of Bergen, 5021 Bergen, Norway;
- National Center for Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway
| | - Hans Steinsland
- Centre for Intervention Science in Maternal and Child Health (CISMAC), Centre of International Health, Department of Global Public Health and Primary Care, University of Bergen, 5020 Bergen, Norway;
- Department of Biomedicine, University of Bergen, 5020 Bergen, Norway
| | - Kurt Hanevik
- Department of Clinical Science, University of Bergen, 5021 Bergen, Norway;
- National Center for Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway
| |
Collapse
|
5
|
Rim S, Sakkestad ST, Zhou F, Gullaksen SE, Skavland J, Chauhan SK, Steinsland H, Hanevik K. Dynamics of circulating lymphocytes responding to human experimental enterotoxigenic Escherichia coli infection. Eur J Immunol 2023; 53:e2250254. [PMID: 37102399 DOI: 10.1002/eji.202250254] [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: 11/03/2022] [Revised: 03/11/2023] [Accepted: 04/24/2023] [Indexed: 04/28/2023]
Abstract
Enterotoxigenic Escherichia coli (ETEC) is an important cause of children's and travelers' diarrhea, with no licensed vaccine. This study aimed to explore the role of cellular immunity in protection against human ETEC infection. Nine volunteers were experimentally infected with ETEC, of which six developed diarrhea. Lymphocytes were collected from peripheral blood buffy coats, before and 3, 5, 6, 7, 10, and 28 days after dose ingestion, and 34 phenotypic and functional markers were examined by mass cytometry. Thirty-three cell populations, derived by manually merging 139 cell clusters from the X-shift unsupervised clustering algorithm, were analyzed. Initially, the diarrhea group responded with increased CD56dim CD16+ natural killer cells, dendritic cells tended to rise, and mucosal-associated invariant T cells decreased. On day 5-7, an increase in plasmablasts was paralleled by a consistent rise in CD4+ Th17-like effector memory and regulatory cell subsets. CD4+ Th17-like central memory cells peaked on day 10. All Th17-like cell populations showed increased expression of activation, gut-homing, and proliferation markers. Interestingly, in the nondiarrhea group, these same CD4+ Th17-like cell populations expanded earlier, normalizing around day 7. Earlier development of these CD4+ Th17-like cell populations in the nondiarrhea group may suggest a recall response and a potential role in controlling ETEC infections.
Collapse
Affiliation(s)
- Sehee Rim
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Sunniva T Sakkestad
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Fan Zhou
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Stein-Erik Gullaksen
- Department of Clinical Science, Centre of Cancer Biomarkers (CCBIO), University of Bergen, Bergen, Norway
- Hematology Section, Department of Internal Medicine, Helse Bergen, Bergen, Norway
| | - Jørn Skavland
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Sudhir K Chauhan
- Division of Cancer Medicine, Department of Cancer Immunology, Oslo University Hospital, Oslo, Norway
| | - Hans Steinsland
- Department of Global Public Health and Primary Care, Faculty of Medicine, Centre for Intervention Science in Maternal and Child Health (CISMAC), Centre for International Health, University of Bergen, Bergen, Norway
- Department of Biomedicine, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Kurt Hanevik
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
- Department of Medicine, Norwegian National Advisory Unit on Tropical Infectious Diseases, Haukeland University Hospital, Bergen, Norway
| |
Collapse
|
6
|
Strong Association between Diarrhea and Concentration of Enterotoxigenic Escherichia coli Strain TW10722 in Stools of Experimentally Infected Volunteers. Pathogens 2023; 12:pathogens12020283. [PMID: 36839555 PMCID: PMC9960819 DOI: 10.3390/pathogens12020283] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/27/2023] [Accepted: 02/07/2023] [Indexed: 02/11/2023] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) strains are a major cause of diarrheal illness in children and travelers in low- and middle-income countries. When volunteers are infected with ETEC strains, as part of experimental infection studies, some do not develop diarrhea. To improve our understanding of how these volunteers are protected, we investigated the association between stool ETEC DNA concentration, as determined by quantitative PCR, and the development and severity of disease in 21 volunteers who had been experimentally infected with ETEC strain TW10722. We found a strong association between maximum stool ETEC DNA concentration and the development of diarrhea: all of the 11 volunteers who did not develop diarrhea had <0.99% TW10722-specific DNA in their stools throughout the follow-up period of up to 9 days, while all of the 10 volunteers who did develop diarrhea had maximum DNA concentrations of ≥0.99%. Most likely, these maximum stool TW10722 DNA concentrations reflect the level of intestinal colonization and the risk of experiencing diarrhea, thereby, seems to be directly dependent on the level of colonization. Thus, the development and availability of vaccines and other prophylactic measures, even if they only partially reduce colonization, could be important in the effort to reduce the burden of ETEC diarrhea.
Collapse
|
7
|
Choy RKM, Bourgeois AL, Ockenhouse CF, Walker RI, Sheets RL, Flores J. Controlled Human Infection Models To Accelerate Vaccine Development. Clin Microbiol Rev 2022; 35:e0000821. [PMID: 35862754 PMCID: PMC9491212 DOI: 10.1128/cmr.00008-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The timelines for developing vaccines against infectious diseases are lengthy, and often vaccines that reach the stage of large phase 3 field trials fail to provide the desired level of protective efficacy. The application of controlled human challenge models of infection and disease at the appropriate stages of development could accelerate development of candidate vaccines and, in fact, has done so successfully in some limited cases. Human challenge models could potentially be used to gather critical information on pathogenesis, inform strain selection for vaccines, explore cross-protective immunity, identify immune correlates of protection and mechanisms of protection induced by infection or evoked by candidate vaccines, guide decisions on appropriate trial endpoints, and evaluate vaccine efficacy. We prepared this report to motivate fellow scientists to exploit the potential capacity of controlled human challenge experiments to advance vaccine development. In this review, we considered available challenge models for 17 infectious diseases in the context of the public health importance of each disease, the diversity and pathogenesis of the causative organisms, the vaccine candidates under development, and each model's capacity to evaluate them and identify correlates of protective immunity. Our broad assessment indicated that human challenge models have not yet reached their full potential to support the development of vaccines against infectious diseases. On the basis of our review, however, we believe that describing an ideal challenge model is possible, as is further developing existing and future challenge models.
Collapse
Affiliation(s)
- Robert K. M. Choy
- PATH, Center for Vaccine Innovation and Access, Seattle, Washington, USA
| | - A. Louis Bourgeois
- PATH, Center for Vaccine Innovation and Access, Seattle, Washington, USA
| | | | - Richard I. Walker
- PATH, Center for Vaccine Innovation and Access, Seattle, Washington, USA
| | | | - Jorge Flores
- PATH, Center for Vaccine Innovation and Access, Seattle, Washington, USA
| |
Collapse
|
8
|
Riaz S, Steinsland H, Thorsing M, Andersen AZ, Boysen A, Hanevik K. Characterization of Glycosylation-Specific Systemic and Mucosal IgA Antibody Responses to Escherichia coli Mucinase YghJ (SslE). Front Immunol 2021; 12:760135. [PMID: 34975849 PMCID: PMC8718676 DOI: 10.3389/fimmu.2021.760135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 12/01/2021] [Indexed: 12/04/2022] Open
Abstract
Efforts to develop broadly protective vaccines against pathogenic Escherichia coli are ongoing. A potential antigen candidate for vaccine development is the metalloprotease YghJ, or SslE. YghJ is a conserved mucinase that is immunogenic, heavily glycosylated, and produced by most pathogenic E. coli. To develop efficacious YghJ-based vaccines, there is a need to investigate to what extent potentially protective antibody responses target glycosylated epitopes in YghJ and to describe variations in the quality of YghJ glycosylation in the E. coli population. In this study we estimated the proportion of anti-YghJ IgA antibodies that targeted glycosylated epitopes in serum and intestinal lavage samples from 21 volunteers experimentally infected with wild-type enterotoxigenic E. coli (ETEC) strain TW10722. Glycosylated and non-glycosylated YghJ was expressed, purified, and then gycosylation pattern was verified by BEMAP analysis. Then we used a multiplex bead flow cytometric assay to analyse samples from before and 10 days after TW10722 was ingested. We found that 20 (95%) of the 21 volunteers had IgA antibody responses to homologous, glycosylated YghJ, with a median fold increase in IgA levels of 7.9 (interquartile range [IQR]: 7.1, 11.1) in serum and 3.7 (IQR: 2.1, 10.7) in lavage. The median proportion of anti-YghJ IgA response that specifically targeted glycosylated epitopes was 0.45 (IQR: 0.30, 0.59) in serum and 0.07 (IQR: 0.01, 0.22) in lavage. Our findings suggest that a substantial, but variable, proportion of the IgA antibody response to YghJ in serum during ETEC infection is targeted against glycosylated epitopes, but that gut IgA responses largely target non-glycosylated epitopes. Further research into IgA targeting glycosylated YghJ epitopes is of interest to the vaccine development efforts.
Collapse
Affiliation(s)
- Saman Riaz
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Centre for International Health, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
| | - Hans Steinsland
- Centre for Intervention Science in Maternal and Child Health (CISMAC), Centre for International Health, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | | | | | | | - Kurt Hanevik
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
| |
Collapse
|
9
|
Porter CK, Talaat KR, Isidean SD, Kardinaal A, Chakraborty S, Gutiérrez RL, Sack DA, Bourgeois AL. The Controlled Human Infection Model for Enterotoxigenic Escherichia coli. Curr Top Microbiol Immunol 2021. [PMID: 34669040 DOI: 10.1007/82_2021_242] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The controlled human infection model (CHIM) for enterotoxigenic Escherichia coli (ETEC) has been instrumental in defining ETEC as a causative agent of acute watery diarrhea, providing insights into disease pathogenesis and resistance to illness, and enabling preliminary efficacy evaluations for numerous products including vaccines, immunoprophylactics, and drugs. Over a dozen strains have been evaluated to date, with a spectrum of clinical signs and symptoms that appear to replicate the clinical illness seen with naturally occurring ETEC. Recent advancements in the ETEC CHIM have enhanced the characterization of clinical, immunological, and microbiological outcomes. It is anticipated that omics-based technologies applied to ETEC CHIMs will continue to broaden our understanding of host-pathogen interactions and facilitate the development of primary and secondary prevention strategies.
Collapse
Affiliation(s)
- Chad K Porter
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, MD, 20910, USA.
| | - Kawsar R Talaat
- Center for Immunization Research, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Sandra D Isidean
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, MD, 20910, USA
- Henry M. Jackson Foundation, Bethesda, MD, 20817, USA
| | - Alwine Kardinaal
- NIZO Food Research, Ede, P.O. Box 20, 6710 BA EDE, Kernhemseweg 2, 6718 ZB EDE, The Netherlands
| | - Subhra Chakraborty
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Ramiro L Gutiérrez
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, MD, 20910, USA
| | - David A Sack
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - A Louis Bourgeois
- PATH|Center for Vaccine Innovation and Access, 455 Massachusetts Avenue NW, Suite 1000, Washington, DC, 20001, USA
| |
Collapse
|
10
|
Vaz M, Timms O, Johnson AR, S RK, Ramanathan M, Vaz M. Public perceptions on Controlled Human Infection Model (CHIM) studies-a qualitative pilot study from South India. Monash Bioeth Rev 2021; 39:68-93. [PMID: 33085005 PMCID: PMC7576547 DOI: 10.1007/s40592-020-00121-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2020] [Indexed: 04/12/2023]
Abstract
Research using Controlled Human Infection Models is yet to be attempted in India. This study was conducted to understand the perceptions of the lay public and key opinion makers prior to the possible introduction of such studies in the country. 110 respondents from urban and rural Bangalore district were interviewed using qualitative research methods of Focus Group Discussions and In-depth Interviews. The data was analyzed using grounded theory. Safety was a key concern of the lay public, expressed in terms of fear of death. The notion of infecting a healthy volunteer, the possibility of continued effects beyond the study duration and the likelihood of vulnerable populations volunteering solely for monetary benefit, were ethical concerns. Public good outcomes such as effective treatments, targeted vaccines and prevention of diseases was necessary justification for such studies. However, the comprehension of this benefit was not clear among non-medical, non-technical respondents and suggestions to seek alternatives to CHIMs repeatedly arose. There was a great deal of deflection-with each constituency feeling that people other than themselves may be ideally suited as participants. Risk takers, those without dependents, the more health and research literate, financially sound and those with an altruistic bent of mind emerged as possible CHIM volunteers. While widespread awareness and advocacy about CHIM is essential, listening to plural voices is the first step in public engagement in ethically contentious areas. Continued engagement and inclusive deliberative processes are required to redeem the mistrust of the public in research and rebuild faith in regulatory systems.
Collapse
Affiliation(s)
- Manjulika Vaz
- Division of Health and Humanities, St John's Research Institute, St John's Medical College, Bangalore, 560034, India.
| | - Olinda Timms
- Division of Health and Humanities, St John's Research Institute, St John's Medical College, Bangalore, 560034, India
| | - Avita Rose Johnson
- Department of Community Health, St John's Medical College, Bangalore, India
| | - Rathna Kumari S
- Department of Community Health, St John's Medical College, Bangalore, India
| | - Mala Ramanathan
- Achutha Menon Centre for Health Science Studies, Sree Chitra Tirunal Institute for Medical Sciences and Technology Medical College, Thiruvananthapuram, Kerala, India
| | - Mario Vaz
- Division of Health and Humanities, St John's Research Institute, St John's Medical College, Bangalore, 560034, India
- Department of Physiology, St John's Medical College, Bangalore, India
| |
Collapse
|
11
|
A new human challenge model for testing heat-stable toxin-based vaccine candidates for enterotoxigenic Escherichia coli diarrhea - dose optimization, clinical outcomes, and CD4+ T cell responses. PLoS Negl Trop Dis 2019; 13:e0007823. [PMID: 31665141 PMCID: PMC6844497 DOI: 10.1371/journal.pntd.0007823] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 11/11/2019] [Accepted: 10/02/2019] [Indexed: 12/17/2022] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) are a common cause of diarrheal illness in young children and travelers. There is yet no licensed broadly protective vaccine against ETEC. One promising vaccine development strategy is to target strains expressing the heat-stable toxin (ST), particularly the human ST (STh), since infections with these strains are among the leading causes of diarrhea in children in low-and-middle income countries. A human challenge model based on an STh-only ETEC strain will be useful to evaluate the protective efficacy of new ST-based vaccine candidates. To develop this model, we experimentally infected 21 healthy adult volunteers with the epidemiologically relevant STh-only ETEC strain TW10722, identified a suitable dose, assessed safety, and characterized clinical outcomes and immune responses caused by the infection. Doses of 1×1010 colony-forming units (CFU) of TW10722 gave a suitable attack risk of 67% for moderate or severe diarrhea and an overall diarrhea attack risk of 78%. Non-diarrheal symptoms were mostly mild or moderate, and there were no serious adverse events. During the first month after ingesting the challenge strain, we measured significant increases in both activated CD4+ T cells and levels of serum IgG and IgA antibodies targeting coli surface antigen 5 (CS5) and 6 (CS6), as well as the E. coli mucinase YghJ. The CS5-specific CD4+ T cell and antibody responses were still significantly elevated one year after experimental infection. In conclusion, we have developed a safe STh-only ETEC-based human challenge model which can be efficiently used in Phase 2B trials to evaluate the protective efficacy of new ST-based vaccine candidates. Enterotoxigenic Escherichia coli (ETEC) is a common cause of diarrheal illness in young children living in low- and middle-income countries and in travelers to these countries. Several ETEC vaccine candidates are currently being developed, but so far, no broadly protective vaccines have been licensed. Since most moderate and severe ETEC diarrheal episodes are caused by strains that express the heat-stable enterotoxin (ST), ST represents a promising vaccine target. Here we present a human challenge model that can be used to estimate the protective efficacy of ST-based vaccine candidates in clinical vaccine trials. The model is based on the epidemiologically relevant ST-only ETEC strain TW10722, which we show is safe to ingest by volunteers and readily induce diarrhea.
Collapse
|