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Chávez-Arroyo A, Portnoy DA. Why is Listeria monocytogenes such a potent inducer of CD8+ T-cells? Cell Microbiol 2021; 22:e13175. [PMID: 32185899 DOI: 10.1111/cmi.13175] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/21/2020] [Accepted: 01/22/2020] [Indexed: 12/20/2022]
Abstract
Listeria monocytogenes is a rapidly growing, Gram-positive, facultative intracellular pathogen that has been used for over 5 decades as a model to study basic aspects of infection and immunity. In a murine intravenous infection model, immunisation with a sublethal infection of L. monocytogenes initially leads to rapid intracellular multiplication followed by clearance of the bacteria and ultimately culminates in the development of long-lived cell-mediated immunity (CMI) mediated by antigen-specific CD8+ cytotoxic T-cells. Importantly, effective immunisation requires live, replicating bacteria. In this review, we summarise the cell and immunobiology of L. monocytogenes infection and discuss aspects of its pathogenesis that we suspect lead to robust CMI. We suggest five specific features of L. monocytogenes infection that positively impact the development of CMI: (a) the bacteria have a predilection for professional antigen-presenting cells; (b) the bacteria escape from phagosomes, grow, and secrete antigens into the host cell cytosol; (c) bacterial-secreted proteins enter the major histocompatibility complex (MHC) class I pathway of antigen processing and presentation; (d) the bacteria do not induce rapid host cell death; and (e) cytosolic bacteria induce a cytokine response that favours CMI. Collectively, these features make L. monocytogenes an attractive vaccine vector for both infectious disease applications and cancer immunotherapy.
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Affiliation(s)
- Alfredo Chávez-Arroyo
- Graduate Group in Microbiology, University of California, Berkeley, Berkeley, California
| | - Daniel A Portnoy
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California.,Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California
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Nguyen BN, Chávez-Arroyo A, Cheng MI, Krasilnikov M, Louie A, Portnoy DA. TLR2 and endosomal TLR-mediated secretion of IL-10 and immune suppression in response to phagosome-confined Listeria monocytogenes. PLoS Pathog 2020; 16:e1008622. [PMID: 32634175 PMCID: PMC7340287 DOI: 10.1371/journal.ppat.1008622] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 05/12/2020] [Indexed: 01/24/2023] Open
Abstract
Listeria monocytogenes is a facultative intracellular bacterial pathogen that escapes from phagosomes and induces a robust adaptive immune response in mice, while mutants unable to escape phagosomes fail to induce a robust adaptive immune response and suppress the immunity to wildtype bacteria when co-administered. The capacity to suppress immunity can be reversed by blocking IL-10. In this study, we sought to understand the host receptors that lead to secretion of IL-10 in response to phagosome-confined L. monocytogenes (Δhly), with the ultimate goal of generating strains that fail to induce IL-10. We conducted a transposon screen to identify Δhly L. monocytogenes mutants that induced significantly more or less IL-10 secretion in bone marrow-derived macrophages (BMMs). A transposon insertion in lgt, which encodes phosphatidylglycerol-prolipoprotein diacylglyceryl transferase and is essential for the formation of lipoproteins, induced significantly reduced IL-10 secretion. Mutants with transposon insertions in pgdA and oatA, which encode peptidoglycan N-acetylglucosamine deacetylase and O-acetyltransferase, are sensitive to lysozyme and induced enhanced IL-10 secretion. A ΔhlyΔpgdAΔoatA strain was killed in BMMs and induced enhanced IL-10 secretion that was dependent on Unc93b1, a trafficking molecule required for signaling of nucleic acid-sensing TLRs. These data revealed that nucleic acids released by bacteriolysis triggered endosomal TLR-mediated IL-10 secretion. Secretion of IL-10 in response to infection with the parental strain was mostly TLR2-dependent, while IL-10 secretion in response to lysozyme-sensitive strains was dependent on TLR2 and Unc93b1. In mice, the IL-10 response to vacuole-confined L. monocytogenes was also dependent on TLR2 and Unc93b1. Co-administration of Δhly and ΔactA resulted in suppressed immunity in WT mice, but not in mice with mutations in Unc93b1. These data revealed that secretion of IL-10 in response to L. monocytogenes infection in vitro is mostly TLR2-dependent and immune suppression by phagosome-confined bacteria in vivo is mostly dependent on endosomal TLRs.
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Affiliation(s)
- Brittney N. Nguyen
- Graduate Group in Microbiology, University of California, Berkeley, Berkeley, California, United States of America
| | - Alfredo Chávez-Arroyo
- Graduate Group in Microbiology, University of California, Berkeley, Berkeley, California, United States of America
| | - Mandy I. Cheng
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
| | - Maria Krasilnikov
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
| | - Alexander Louie
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
| | - Daniel A. Portnoy
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, United States of America
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Lopez CA, Miller BM, Rivera-Chávez F, Velazquez EM, Byndloss MX, Chávez-Arroyo A, Lokken KL, Tsolis RM, Winter SE, Bäumler AJ. Virulence factors enhance Citrobacter rodentium expansion through aerobic respiration. Science 2016; 353:1249-53. [PMID: 27634526 PMCID: PMC5127919 DOI: 10.1126/science.aag3042] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 08/05/2016] [Indexed: 12/20/2022]
Abstract
Citrobacter rodentium uses a type III secretion system (T3SS) to induce colonic crypt hyperplasia in mice, thereby gaining an edge during its competition with the gut microbiota through an unknown mechanism. Here, we show that by triggering colonic crypt hyperplasia, the C. rodentium T3SS induced an excessive expansion of undifferentiated Ki67-positive epithelial cells, which increased oxygenation of the mucosal surface and drove an aerobic C. rodentium expansion in the colon. Treatment of mice with the γ-secretase inhibitor dibenzazepine to diminish Notch-driven colonic crypt hyperplasia curtailed the fitness advantage conferred by aerobic respiration during C. rodentium infection. We conclude that C. rodentium uses its T3SS to induce histopathological lesions that generate an intestinal microenvironment in which growth of the pathogen is fueled by aerobic respiration.
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Affiliation(s)
- Christopher A Lopez
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, One Shields Avenue, Davis, CA, USA
| | - Brittany M Miller
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, One Shields Avenue, Davis, CA, USA
| | - Fabian Rivera-Chávez
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, One Shields Avenue, Davis, CA, USA
| | - Eric M Velazquez
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, One Shields Avenue, Davis, CA, USA
| | - Mariana X Byndloss
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, One Shields Avenue, Davis, CA, USA
| | - Alfredo Chávez-Arroyo
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, One Shields Avenue, Davis, CA, USA
| | - Kristen L Lokken
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, One Shields Avenue, Davis, CA, USA
| | - Renée M Tsolis
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, One Shields Avenue, Davis, CA, USA
| | - Sebastian E Winter
- Department of Microbiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, USA
| | - Andreas J Bäumler
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, One Shields Avenue, Davis, CA, USA.
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