Salmonella-specific CD4+ T cells in the murine model of Salmonellosis
Salmonella-specific CD4+ T cells in the murine model of Salmonellosis
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01.03.2035Type of Scholarly Publication
DissertationDate of Exam
20.12.2024Date of Publication
28.02.2025Advisor
Förster, IrmgardCo-Referee
Kurts, ChristianMetadata
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Abstract
Salmonella infection is a major cause of morbidity and mortality worldwide, which requires a deeper comprehension of the protective immune mechanisms, in order to develop more effective vaccines. While the importance of CD4+ T cells during Salmonellosis is well established, the specific antigenic targets, in vivo dynamics and phenotype of Salmonella-specific CD4+ T cells remain incompletely understood.
In this project, CD4+ T cell antigen targets were elucidated from a novel Salmonella-derived MHC class II immunopeptidome and their immunogenicity was validated in a murine model of Salmonellosis. Four antigens were selected for generating peptide:MHC class II tetramers. These tetramers facilitated the direct identification, enumeration and characterization of previously unreported Salmonella-specific CD4+ T cells during murine Salmonellosis. The selected antigenic targets varied in their immunogenicity as well as subcellular localization, expression levels and conservation of their source proteins, aimed at representing T cell responses to diverse antigens.
Remarkably, in some but not all animals, analysis of tetramer and TCRß staining revealed at least two distinct populations of specific CD4+ T cells, prompting investigation into TCR usage by single-cell RNA sequencing. This approach shed light on the reasons behind the existence of multiple populations and provided insights into the polyclonallity of Salmonella-specific CD4+ T cell responses.
Moreover, Salmonella-specific CD4+ T cells exhibited a T helper 1 effector phenotype with surface marker expression consistent with homing to the liver, a critical site of Salmonella infection. Intriguingly, Salmonella-specific CD4+ T cells were readily available for reamplification upon challenge with wild type Salmonella, if animals were previously vaccinated with an attenuated Salmonella strain, suggesting that the selected peptides may have vaccine potential.
Additionally, Salmonella overexpression mutants were generated, increasing the expression of one of the source proteins of the antigenic targets. When these mutants were used for infection experiments, the frequency of specific CD4+ T cells was increased, as did the frequency when multiple populations stained with a single tetramer were identified, without affecting the Salmonella-induced gross pathology. This approach offers new avenues for understanding the dynamics of Salmonella-specific CD4+ T cell responses and their modulation for therapeutic interventions.
Our results demonstrate the feasibility and utility of using immunopeptidomics and tetramer technology to study Salmonella-specific CD4+ T cell immunity in a murine model of Salmonellosis. Furthermore, the novel antigens and tetramers provide valuable tools for understanding the mechanism of protective immunity, paving the way for the urgently needed development of next-generation vaccine formulations against Salmonella infections.
In this project, CD4+ T cell antigen targets were elucidated from a novel Salmonella-derived MHC class II immunopeptidome and their immunogenicity was validated in a murine model of Salmonellosis. Four antigens were selected for generating peptide:MHC class II tetramers. These tetramers facilitated the direct identification, enumeration and characterization of previously unreported Salmonella-specific CD4+ T cells during murine Salmonellosis. The selected antigenic targets varied in their immunogenicity as well as subcellular localization, expression levels and conservation of their source proteins, aimed at representing T cell responses to diverse antigens.
Remarkably, in some but not all animals, analysis of tetramer and TCRß staining revealed at least two distinct populations of specific CD4+ T cells, prompting investigation into TCR usage by single-cell RNA sequencing. This approach shed light on the reasons behind the existence of multiple populations and provided insights into the polyclonallity of Salmonella-specific CD4+ T cell responses.
Moreover, Salmonella-specific CD4+ T cells exhibited a T helper 1 effector phenotype with surface marker expression consistent with homing to the liver, a critical site of Salmonella infection. Intriguingly, Salmonella-specific CD4+ T cells were readily available for reamplification upon challenge with wild type Salmonella, if animals were previously vaccinated with an attenuated Salmonella strain, suggesting that the selected peptides may have vaccine potential.
Additionally, Salmonella overexpression mutants were generated, increasing the expression of one of the source proteins of the antigenic targets. When these mutants were used for infection experiments, the frequency of specific CD4+ T cells was increased, as did the frequency when multiple populations stained with a single tetramer were identified, without affecting the Salmonella-induced gross pathology. This approach offers new avenues for understanding the dynamics of Salmonella-specific CD4+ T cell responses and their modulation for therapeutic interventions.
Our results demonstrate the feasibility and utility of using immunopeptidomics and tetramer technology to study Salmonella-specific CD4+ T cell immunity in a murine model of Salmonellosis. Furthermore, the novel antigens and tetramers provide valuable tools for understanding the mechanism of protective immunity, paving the way for the urgently needed development of next-generation vaccine formulations against Salmonella infections.
Classification (DDC)
570 Biowissenschaften, Biologie 610 Medizin, GesundheitSemeniuk, Adrian David: Salmonella-specific CD4+ T cells in the murine model of Salmonellosis. - Bonn, 2025. - Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn, University of Melbourne.
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5-80455
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5-80455
@phdthesis{handle:20.500.11811/12873,
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5-80455,
author = {{Adrian David Semeniuk}},
title = {Salmonella-specific CD4+ T cells in the murine model of Salmonellosis},
school = {{Rheinische Friedrich-Wilhelms-Universität Bonn} and {University of Melbourne}},
year = 2025,
month = feb,
note = {Salmonella infection is a major cause of morbidity and mortality worldwide, which requires a deeper comprehension of the protective immune mechanisms, in order to develop more effective vaccines. While the importance of CD4+ T cells during Salmonellosis is well established, the specific antigenic targets, in vivo dynamics and phenotype of Salmonella-specific CD4+ T cells remain incompletely understood.
In this project, CD4+ T cell antigen targets were elucidated from a novel Salmonella-derived MHC class II immunopeptidome and their immunogenicity was validated in a murine model of Salmonellosis. Four antigens were selected for generating peptide:MHC class II tetramers. These tetramers facilitated the direct identification, enumeration and characterization of previously unreported Salmonella-specific CD4+ T cells during murine Salmonellosis. The selected antigenic targets varied in their immunogenicity as well as subcellular localization, expression levels and conservation of their source proteins, aimed at representing T cell responses to diverse antigens.
Remarkably, in some but not all animals, analysis of tetramer and TCRß staining revealed at least two distinct populations of specific CD4+ T cells, prompting investigation into TCR usage by single-cell RNA sequencing. This approach shed light on the reasons behind the existence of multiple populations and provided insights into the polyclonallity of Salmonella-specific CD4+ T cell responses.
Moreover, Salmonella-specific CD4+ T cells exhibited a T helper 1 effector phenotype with surface marker expression consistent with homing to the liver, a critical site of Salmonella infection. Intriguingly, Salmonella-specific CD4+ T cells were readily available for reamplification upon challenge with wild type Salmonella, if animals were previously vaccinated with an attenuated Salmonella strain, suggesting that the selected peptides may have vaccine potential.
Additionally, Salmonella overexpression mutants were generated, increasing the expression of one of the source proteins of the antigenic targets. When these mutants were used for infection experiments, the frequency of specific CD4+ T cells was increased, as did the frequency when multiple populations stained with a single tetramer were identified, without affecting the Salmonella-induced gross pathology. This approach offers new avenues for understanding the dynamics of Salmonella-specific CD4+ T cell responses and their modulation for therapeutic interventions.
Our results demonstrate the feasibility and utility of using immunopeptidomics and tetramer technology to study Salmonella-specific CD4+ T cell immunity in a murine model of Salmonellosis. Furthermore, the novel antigens and tetramers provide valuable tools for understanding the mechanism of protective immunity, paving the way for the urgently needed development of next-generation vaccine formulations against Salmonella infections.},
url = {https://hdl.handle.net/20.500.11811/12873}
}
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5-80455,
author = {{Adrian David Semeniuk}},
title = {Salmonella-specific CD4+ T cells in the murine model of Salmonellosis},
school = {{Rheinische Friedrich-Wilhelms-Universität Bonn} and {University of Melbourne}},
year = 2025,
month = feb,
note = {Salmonella infection is a major cause of morbidity and mortality worldwide, which requires a deeper comprehension of the protective immune mechanisms, in order to develop more effective vaccines. While the importance of CD4+ T cells during Salmonellosis is well established, the specific antigenic targets, in vivo dynamics and phenotype of Salmonella-specific CD4+ T cells remain incompletely understood.
In this project, CD4+ T cell antigen targets were elucidated from a novel Salmonella-derived MHC class II immunopeptidome and their immunogenicity was validated in a murine model of Salmonellosis. Four antigens were selected for generating peptide:MHC class II tetramers. These tetramers facilitated the direct identification, enumeration and characterization of previously unreported Salmonella-specific CD4+ T cells during murine Salmonellosis. The selected antigenic targets varied in their immunogenicity as well as subcellular localization, expression levels and conservation of their source proteins, aimed at representing T cell responses to diverse antigens.
Remarkably, in some but not all animals, analysis of tetramer and TCRß staining revealed at least two distinct populations of specific CD4+ T cells, prompting investigation into TCR usage by single-cell RNA sequencing. This approach shed light on the reasons behind the existence of multiple populations and provided insights into the polyclonallity of Salmonella-specific CD4+ T cell responses.
Moreover, Salmonella-specific CD4+ T cells exhibited a T helper 1 effector phenotype with surface marker expression consistent with homing to the liver, a critical site of Salmonella infection. Intriguingly, Salmonella-specific CD4+ T cells were readily available for reamplification upon challenge with wild type Salmonella, if animals were previously vaccinated with an attenuated Salmonella strain, suggesting that the selected peptides may have vaccine potential.
Additionally, Salmonella overexpression mutants were generated, increasing the expression of one of the source proteins of the antigenic targets. When these mutants were used for infection experiments, the frequency of specific CD4+ T cells was increased, as did the frequency when multiple populations stained with a single tetramer were identified, without affecting the Salmonella-induced gross pathology. This approach offers new avenues for understanding the dynamics of Salmonella-specific CD4+ T cell responses and their modulation for therapeutic interventions.
Our results demonstrate the feasibility and utility of using immunopeptidomics and tetramer technology to study Salmonella-specific CD4+ T cell immunity in a murine model of Salmonellosis. Furthermore, the novel antigens and tetramers provide valuable tools for understanding the mechanism of protective immunity, paving the way for the urgently needed development of next-generation vaccine formulations against Salmonella infections.},
url = {https://hdl.handle.net/20.500.11811/12873}
}
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