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Kern K, Delaroque N, Boysen A, Puder M, Wendt R, Kölsch A, Ehrentreich-Förster E, Stærk K, Andersen TE, Andersen K, Lund L, Szardenings M. Glycosylation of bacterial antigens changes epitope patterns. Front Immunol 2023; 14:1258136. [PMID: 37954588 PMCID: PMC10637626 DOI: 10.3389/fimmu.2023.1258136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 09/21/2023] [Indexed: 11/14/2023] Open
Abstract
Introduction Unlike glycosylation of proteins expressed in mammalian systems, bacterial glycosylation is often neglected in the development of recombinant vaccines. Methods Here, we compared the effects of glycosylation of YghJ, an Escherichia coli protein important for mucus attachment of bacteria causing in urinary tract infections (UTIs). A novel method based on statistical evaluation of phage display for the identification and comparison of epitopes and mimotopes of anti-YghJ antibodies in the sera was used. This is the first time that the effect of glycosylation of a recombinant bacterial antigen has been studied at the peptide epitope level. Results The study identifies differences in the immune response for (non)-glycosylated antigens in rabbits and pigs and compares them to a large group of patients with UTI, which have been diagnosed as positive for various bacterial pathogens. We identified glycosylation-specific peptide epitopes, a large immunological similarity between different UTI pathogens, and a broad peptide epitope pattern in patients and animals, which could result in a variable response in patients upon vaccination. Discussion This epitope analysis indicates that the vaccination of rabbits and pigs raises antibodies that translate well into the human immune system. This study underlines the importance of glycosylation in bacterial vaccines and provides detailed immune diagnostic methods to understand individual immune responses to vaccines.
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Affiliation(s)
- Karolin Kern
- Ligand Development Unit, Fraunhofer Institute for Cell Therapy and Immunology (IZI), Leipzig, Germany
- Epitopic, Leipzig, Germany
| | - Nicolas Delaroque
- Ligand Development Unit, Fraunhofer Institute for Cell Therapy and Immunology (IZI), Leipzig, Germany
| | | | | | - Ralph Wendt
- Department of Nephrology, St. Georg Hospital Leipzig, Leipzig, Germany
| | - Andreas Kölsch
- MicroDiagnostics Unit, Fraunhofer Institute for Cell Therapy and Immunology (IZI), Leipzig, Germany
| | - Eva Ehrentreich-Förster
- Molekulare und Zelluläre Bioanalytik Unit, Fraunhofer Institute for Cell Therapy and Immunology, Branch Bioanalytics and Bioprocesses (IZI-BB), Golm, Germany
| | - Kristian Stærk
- Department of Clinical Microbiology, Odense University Hospital, Odense, Denmark
- Research Unit of Clinical Microbiology, University of Southern Denmark, Odense, Denmark
| | - Thomas Emil Andersen
- Department of Clinical Microbiology, Odense University Hospital, Odense, Denmark
- Research Unit of Clinical Microbiology, University of Southern Denmark, Odense, Denmark
| | - Karin Andersen
- Department of Urology, Odense University Hospital, Odense, Denmark
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Lars Lund
- Department of Urology, Odense University Hospital, Odense, Denmark
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Michael Szardenings
- Ligand Development Unit, Fraunhofer Institute for Cell Therapy and Immunology (IZI), Leipzig, Germany
- Epitopic, Leipzig, Germany
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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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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
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Thorsing M, Krogh TJ, Vitved L, Nawrocki A, Jakobsen R, Larsen MR, Chakraborty S, Bourgeois AL, Andersen AZ, Boysen A. Linking inherent O-Linked Protein Glycosylation of YghJ to Increased Antigen Potential. Front Cell Infect Microbiol 2021; 11:705468. [PMID: 34490144 PMCID: PMC8417355 DOI: 10.3389/fcimb.2021.705468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/23/2021] [Indexed: 11/13/2022] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) is a WHO priority pathogen and vaccine target which causes infections in low-income and middle-income countries, travelers visiting endemic regions. The global urgent demand for an effective preventive intervention has become more pressing as ETEC strains have become increasingly multiple antibiotic resistant. However, the vaccine development pipeline has been slow to address this urgent need. To date, vaccine development has focused mainly on canonical antigens such as colonization factors and expressed toxins but due to genomic plasticity of this enteric pathogen, it has proven difficult to develop effective vaccines. In this study, we investigated the highly conserved non-canonical vaccine candidate YghJ/SsLE. Using the mass spectrometry-based method BEMAP, we demonstrate that YghJ is hyperglycosylated in ETEC and identify 54 O-linked Set/Thr residues within the 1519 amino acid primary sequence. The glycosylation sites are evenly distributed throughout the sequence and do not appear to affect the folding of the overall protein structure. Although the glycosylation sites only constitute a minor subpopulation of the available epitopes, we observed a notable difference in the immunogenicity of the glycosylated YghJ and the non-glycosylated protein variant. We can demonstrate by ELISA that serum from patients enrolled in an ETEC H10407 controlled infection study are significantly more reactive with glycosylated YghJ compared to the non-glycosylated variant. This study provides an important link between O-linked glycosylation and the relative immunogenicity of bacterial proteins and further highlights the importance of this observation in considering ETEC proteins for inclusion in future broad coverage subunit vaccine candidates.
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Affiliation(s)
| | | | - Lars Vitved
- Department of Cancer and Inflammation Research, University of Southern Denmark, Odense, Denmark
| | - Arkadiusz Nawrocki
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | | | - Martin R. Larsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Subhra Chakraborty
- Center for Immunization Research, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - A. Louis Bourgeois
- Center for Vaccine Innovation and Access, PATH, Washington, DC, United States
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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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