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Nguyen AT, McSorley SJ. Fighting the enemy within: Systemic immune defense against mucosal Salmonella infection. Immunol Lett 2024; 270:106930. [PMID: 39343314 DOI: 10.1016/j.imlet.2024.106930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 09/05/2024] [Accepted: 09/17/2024] [Indexed: 10/01/2024]
Abstract
Salmonella infection remains a persistent global health threat, as different serovars induce a range of clinical disease, depending upon bacterial virulence and host susceptibility. While some Salmonella serovars induce gastroenteritis in healthy individuals, others can cause more serious systemic enteric fever or invasive nontyphoidal Salmonellosis. The rise of antibiotic resistance, coupled with the absence of effective vaccines for most serovars, perpetuates the spread of Salmonella in endemic regions. A detailed mechanistic understanding of immunity to Salmonella infections has been aided by the availability of mouse models that have served as a valuable tool for understanding host-pathogen interactions under controlled laboratory conditions. These mouse studies have delineated the processes by which early inflammation is triggered after infection, how adaptive immunity is initiated in lymphoid tissues, and the contribution of lymphocyte memory responses to resistance. While recent progress has been made in vaccine development for some causes of enteric fever, deeper understanding of Salmonella-specific immune memory might allow the formation of new vaccines for all serovars. This review will provide a summary of our understanding of vaccination and protective immunity to Salmonella with a focus on recent developments in T cell memory formation.
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Affiliation(s)
- Alana T Nguyen
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, CA 95616, USA
| | - Stephen J McSorley
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, CA 95616, USA.
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Rixon JA, Fong KD, Morris C, Nguyen AT, Depew CE, McSorley SJ. Elimination of Chlamydia muridarum from the female reproductive tract is IL-12p40 dependent, but independent of Th1 and Th2 cells. PLoS Pathog 2024; 20:e1011914. [PMID: 38166152 PMCID: PMC10786385 DOI: 10.1371/journal.ppat.1011914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 01/12/2024] [Accepted: 12/19/2023] [Indexed: 01/04/2024] Open
Abstract
Chlamydia vaccine approaches aspire to induce Th1 cells for optimal protection, despite the fact that there is no direct evidence demonstrating Th1-mediated Chlamydia clearance from the female reproductive tract (FRT). We recently reported that T-bet-deficient mice can resolve primary Chlamydia infection normally, undermining the potentially protective role of Th1 cells in Chlamydia immunity. Here, we show that T-bet-deficient mice develop robust Th17 responses and that mice deficient in Th17 cells exhibit delayed bacterial clearance, demonstrating that Chlamydia-specific Th17 cells represent an underappreciated protective population. Additionally, Th2-deficient mice competently clear cervicovaginal infection. Furthermore, we show that sensing of IFN-γ by non-hematopoietic cells is essential for Chlamydia immunity, yet bacterial clearance in the FRT does not require IFN-γ secretion by CD4 T cells. Despite the fact that Th1 cells are not necessary for Chlamydia clearance, protective immunity to Chlamydia is still dependent on MHC class-II-restricted CD4 T cells and IL-12p40. Together, these data point to IL-12p40-dependent CD4 effector maturation as essential for Chlamydia immunity, and Th17 cells to a lesser extent, yet neither Th1 nor Th2 cell development is critical. Future Chlamydia vaccination efforts will be more effective if they focus on induction of this protective CD4 T cell population.
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Affiliation(s)
- Jordan A. Rixon
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Kevin D. Fong
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Claire Morris
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Alana T. Nguyen
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Claire E. Depew
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Stephen J. McSorley
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
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Depew CE, McSorley SJ. The role of tissue resident memory CD4 T cells in Salmonella infection: Implications for future vaccines. Vaccine 2023; 41:6426-6433. [PMID: 37739887 DOI: 10.1016/j.vaccine.2023.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 07/20/2023] [Accepted: 09/05/2023] [Indexed: 09/24/2023]
Abstract
Salmonella infections cause a wide range of intestinal and systemic disease that affects global human health. While some vaccines are available, they do not mitigate the impact of Salmonella on endemic areas. Research using Salmonella mouse models has revealed the important role of CD4 T cells and antibody in the development of protective immunity against Salmonella infection. Recent work points to a critical role for hepatic tissue-resident memory lymphocytes in naturally acquired immunity to systemic infection. Thus, understanding the genesis and function of this Salmonella-specific population is an important objective and is the primary focus of this review. Greater understanding of how these memory lymphocytes contribute to bacterial elimination could suggest new approaches to vaccination against an important human pathogen.
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Affiliation(s)
- Claire E Depew
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, CA 95616, USA.
| | - Stephen J McSorley
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, CA 95616, USA.
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Wang N, Scott TA, Kupz A, Shreenivas MM, Peres NG, Hocking DM, Yang C, Jebeli L, Beattie L, Groom JR, Pierce TP, Wakim LM, Bedoui S, Strugnell RA. Vaccine-induced inflammation and inflammatory monocytes promote CD4+ T cell-dependent immunity against murine salmonellosis. PLoS Pathog 2023; 19:e1011666. [PMID: 37733817 PMCID: PMC10547166 DOI: 10.1371/journal.ppat.1011666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 10/03/2023] [Accepted: 09/07/2023] [Indexed: 09/23/2023] Open
Abstract
Prior infection can generate protective immunity against subsequent infection, although the efficacy of such immunity can vary considerably. Live-attenuated vaccines (LAVs) are one of the most effective methods for mimicking this natural process, and analysis of their efficacy has proven instrumental in the identification of protective immune mechanisms. Here, we address the question of what makes a LAV efficacious by characterising immune responses to a LAV, termed TAS2010, which is highly protective (80-90%) against lethal murine salmonellosis, in comparison with a moderately protective (40-50%) LAV, BRD509. Mice vaccinated with TAS2010 developed immunity systemically and were protected against gut-associated virulent infection in a CD4+ T cell-dependent manner. TAS2010-vaccinated mice showed increased activation of Th1 responses compared with their BRD509-vaccinated counterparts, leading to increased Th1 memory populations in both lymphoid and non-lymphoid organs. The optimal development of Th1-driven immunity was closely correlated with the activation of CD11b+Ly6GnegLy6Chi inflammatory monocytes (IMs), the activation of which can be modulated proportionally by bacterial load in vivo. Upon vaccination with the LAV, IMs expressed T cell chemoattractant CXCL9 that attracted CD4+ T cells to the foci of infection, where IMs also served as a potent source of antigen presentation and Th1-promoting cytokine IL-12. The expression of MHC-II in IMs was rapidly upregulated following vaccination and then maintained at an elevated level in immune mice, suggesting IMs may have a role in sustained antigen stimulation. Our findings present a longitudinal analysis of CD4+ T cell development post-vaccination with an intracellular bacterial LAV, and highlight the benefit of inflammation in the development of Th1 immunity. Future studies focusing on the induction of IMs may reveal key strategies for improving vaccine-induced T cell immunity.
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Affiliation(s)
- Nancy Wang
- Department of Microbiology and Immunology, The University of Melbourne, at Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Timothy A. Scott
- Department of Microbiology and Immunology, The University of Melbourne, at Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Andreas Kupz
- Department of Microbiology and Immunology, The University of Melbourne, at Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Meghanashree M. Shreenivas
- Department of Microbiology and Immunology, The University of Melbourne, at Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Newton G. Peres
- Department of Microbiology and Immunology, The University of Melbourne, at Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Dianna M. Hocking
- Department of Microbiology and Immunology, The University of Melbourne, at Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Chenying Yang
- Department of Microbiology and Immunology, The University of Melbourne, at Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Leila Jebeli
- Department of Microbiology and Immunology, The University of Melbourne, at Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Lynette Beattie
- Department of Microbiology and Immunology, The University of Melbourne, at Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Joanna R. Groom
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Thomas P. Pierce
- Ludwig Institute for Cancer Research, Melbourne-Parkville Branch, Parkville, Victoria, Australia
| | - Linda M. Wakim
- Department of Microbiology and Immunology, The University of Melbourne, at Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Sammy Bedoui
- Department of Microbiology and Immunology, The University of Melbourne, at Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Richard A. Strugnell
- Department of Microbiology and Immunology, The University of Melbourne, at Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
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Marcial-Juárez E, Pérez-Toledo M, Nayar S, Pipi E, Alshayea A, Persaud R, Jossi SE, Lamerton R, Barone F, Henderson IR, Cunningham AF. Salmonella infection induces the reorganization of follicular dendritic cell networks concomitant with the failure to generate germinal centers. iScience 2023; 26:106310. [PMID: 36950118 PMCID: PMC10025972 DOI: 10.1016/j.isci.2023.106310] [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: 12/13/2022] [Revised: 02/07/2023] [Accepted: 02/26/2023] [Indexed: 03/06/2023] Open
Abstract
Germinal centers (GCs) are sites where plasma and memory B cells form to generate high-affinity, Ig class-switched antibodies. Specialized stromal cells called follicular dendritic cells (FDCs) are essential for GC formation. During systemic Salmonella Typhimurium (STm) infection GCs are absent, whereas extensive extrafollicular and switched antibody responses are maintained. The mechanisms that underpin the absence of GC formation are incompletely understood. Here, we demonstrate that STm induces a reversible disruption of niches within the splenic microenvironment, including the T and B cell compartments and the marginal zone. Alongside these effects after infection, mature FDC networks are strikingly absent, whereas immature FDC precursors, including marginal sinus pre-FDCs (MadCAM-1+) and perivascular pre-FDCs (PDGFRβ+) are enriched. As normal FDC networks re-establish, extensive GCs become detectable throughout the spleen. Therefore, the reorganization of FDC networks and the loss of GC responses are key, parallel features of systemic STm infections.
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Affiliation(s)
- Edith Marcial-Juárez
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, West Midlands, B15 2TT, United Kingdom
| | - Marisol Pérez-Toledo
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, West Midlands, B15 2TT, United Kingdom
| | - Saba Nayar
- Rheumatology Research Group, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, West Midlands, B15 2TT, United Kingdom
| | - Elena Pipi
- Rheumatology Research Group, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, West Midlands, B15 2TT, United Kingdom
| | - Areej Alshayea
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, West Midlands, B15 2TT, United Kingdom
| | - Ruby Persaud
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, West Midlands, B15 2TT, United Kingdom
| | - Sian E. Jossi
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, West Midlands, B15 2TT, United Kingdom
| | - Rachel Lamerton
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, West Midlands, B15 2TT, United Kingdom
| | - Francesca Barone
- Rheumatology Research Group, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, West Midlands, B15 2TT, United Kingdom
- National Institute for Health Research (NIHR) Birmingham Biomedical Research Centre, University Hospitals Birmingham NHS Foundation Trust, UK and Sandwell and West Birmingham Trust, Birmingham, West Midlands, B15 2TH, United Kingdom
| | - Ian R. Henderson
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD4072, Australia
| | - Adam F. Cunningham
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, West Midlands, B15 2TT, United Kingdom
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Th1 cells are dispensable for primary clearance of Chlamydia from the female reproductive tract of mice. PLoS Pathog 2022; 18:e1010333. [PMID: 35196366 PMCID: PMC8901068 DOI: 10.1371/journal.ppat.1010333] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 03/07/2022] [Accepted: 02/02/2022] [Indexed: 01/20/2023] Open
Abstract
Protective immune responses to Chlamydia infection within the female reproductive tract (FRT) are incompletely understood. MHC class II-restricted CD4 Th1 responses are believed to be vital for bacterial clearance due to their capacity to secrete IFN-γ, but an essential requirement for T-bet-expressing Th1 cells has yet to be demonstrated in the mouse model of Chlamydia infection. Here, we investigated the role of T-bet and IFN-γ in primary clearance of Chlamydia after FRT infection. Surprisingly, IFN-γ producing CD4 T cells from the FRT expressed low levels of T-bet throughout infection, suggesting that classical T-bet-expressing Th1 cells are inefficiently generated and therefore unlikely to participate in bacteria clearance. Furthermore, mice deficient in T-bet expression or with a CD4-specific T-bet deficiency cleared FRT infection similarly to wild-type controls. T-bet-deficient mice displayed significant skewing of FRT CD4 T cells towards Th17 responses, demonstrating that compensatory effector pathways are generated in the absence of Th1 cells. In marked contrast, IFN-γ-, and IFN-γR-deficient mice were able to reduce FRT bacterial burdens, but suffered systemic bacterial dissemination and 100% mortality. Together, these data demonstrate that IFN-γ signaling is essential to protect mice from fatal systemic disease, but that classical T-bet-expressing Th1 cells are non-essential for primary clearance within the FRT. Exploring the protective contribution of Th1 cells versus other CD4 effector lineages could provide important information for the generation of new Chlamydia vaccines. The production of IFN-γ by CD4 Th1 cells is thought to be critical for the clearance of Chlamydia from the female reproductive tract (FRT), but this has not been formally tested. Here we demonstrate that T-bet+ Th1 cells are not essential for effective Chlamydia clearance. Furthermore, the impact of IFN-γ deficiency or depletion is largely observed as a failure to control bacterial dissemination, rather than clearance from the FRT. Together, these data suggest that different immunological mechanisms are responsible for restraining systemic spread of bacteria versus FRT control. Defining alternative non-Th1 CD4 effector mechanisms that are responsible for controlling Chlamydia replication within the FRT could be foundational for future vaccine development.
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