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Todnem Sakkestad S, Steinsland H, Skrede S, Kleppa E, Lillebø K, Sævik M, Søyland H, Rykkje Heien A, Gjerde Tellevik M, Barry EM, Sommerfelt H, Hanevik K. Experimental Infection of Human Volunteers with the Heat-Stable Enterotoxin-Producing Enterotoxigenic Escherichia coli Strain TW11681. Pathogens 2019; 8:pathogens8020084. [PMID: 31234485 PMCID: PMC6630672 DOI: 10.3390/pathogens8020084] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 06/17/2019] [Accepted: 06/20/2019] [Indexed: 12/03/2022] Open
Abstract
Infection with enterotoxigenic Escherichia coli (ETEC) producing the heat-stable enterotoxin (ST) is one of the most important causes of childhood diarrhoea in low- and middle-income countries. Here, we undertook a controlled human infection model (CHIM) study to investigate whether ST-producing ETEC strain TW11681 would be suitable for testing the protective efficacy of new ST-based vaccine candidates in vaccine challenge models. In groups of three, nine volunteers ingested 1 × 106, 1 × 107, or 1 × 108 colony-forming units (CFU) of TW11681. Flow cytometry-based assays were used to measure CD4+ T cell responses and antibody levels targeting virulence factors expressed by the strain. We found that infection with TW11681 elicited few and mild symptoms, including mild diarrhoea in two volunteers, both of whom ingested 1 × 106 CFU. Averaged across all volunteers, the CD4+ T cell responses specific for E. coli YghJ mucinase peaked 10 days after infection (3.2-fold (p = 0.016)), while the CD4+ T cell responses specific for Colonization Factor Antigen I (CFA/I) major fimbrial subunit (CfaB) peaked after 28 days (3.6-fold (p = 0.063)). The serum CfaB-specific anti-IgA and anti-IgG/IgM levels were significantly increased and peaked 3 months after infection. Both remained elevated for the duration of the 12-month follow-up. The corresponding anti-YghJ serological response was strongest after 10 days, although a significant increase was seen only for IgA levels (3.2-fold (p = 0.008)). In conclusion, due to its low diarrhoea attack risk, TW11681 is probably not suitable for testing the efficacy of new vaccines in human challenge studies at doses 1 × 106 to 1 × 108. However, the strain may still be useful in CHIMs for studying ETEC host-pathogen interactions.
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Affiliation(s)
- Sunniva Todnem Sakkestad
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Postbox 7804, 5020 Bergen, Norway; (S.T.S.); steinar.skrede@helse-bergen-no (S.S.)
| | - Hans Steinsland
- Centre for International Health, Department of Global Public Health and Primary Care, Faculty of Medicine, University of Bergen, Postbox 7894, 5020 Bergen, Norway;
- Department of Biomedicine, Faculty of Medicine, University of Bergen, Postbox 7804, 5020 Bergen, Norway
| | - Steinar Skrede
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Postbox 7804, 5020 Bergen, Norway; (S.T.S.); steinar.skrede@helse-bergen-no (S.S.)
- Division for Infectious Diseases, Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway; (K.L.); (M.S.); (H.S.); (A.R.H.)
| | - Elisabeth Kleppa
- Department of Microbiology, Haukeland University Hospital, 5021 Bergen, Norway;
| | - Kristine Lillebø
- Division for Infectious Diseases, Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway; (K.L.); (M.S.); (H.S.); (A.R.H.)
| | - Marianne Sævik
- Division for Infectious Diseases, Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway; (K.L.); (M.S.); (H.S.); (A.R.H.)
| | - Hanne Søyland
- Division for Infectious Diseases, Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway; (K.L.); (M.S.); (H.S.); (A.R.H.)
| | - Astrid Rykkje Heien
- Division for Infectious Diseases, Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway; (K.L.); (M.S.); (H.S.); (A.R.H.)
| | - Marit Gjerde Tellevik
- Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway;
| | - Eileen M. Barry
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Halvor Sommerfelt
- Centre for Intervention Science in Material and Child Health (CISMAC), Department of Global Public Health and Primary Care, Faculty of Medicine, University of Bergen, Postbox 7804, 5020 Bergen, Norway;
- Norwegian Institute of Public Health, 222 Oslo Postbox, Norway
| | - Kurt Hanevik
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Postbox 7804, 5020 Bergen, Norway; (S.T.S.); steinar.skrede@helse-bergen-no (S.S.)
- Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway;
- Correspondence: ; Tel.: +47-55-97-30-79
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