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Wang X, Wu H, Fang C, Li Z. Insights into innate immune cell evasion by Chlamydia trachomatis. Front Immunol 2024; 15:1289644. [PMID: 38333214 PMCID: PMC10850350 DOI: 10.3389/fimmu.2024.1289644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 01/11/2024] [Indexed: 02/10/2024] Open
Abstract
Chlamydia trachomatis, is a kind of obligate intracellular pathogen. The removal of C. trachomatis relies primarily on specific cellular immunity. It is currently considered that CD4+ Th1 cytokine responses are the major protective immunity against C. trachomatis infection and reinfection rather than CD8+ T cells. The non-specific immunity (innate immunity) also plays an important role in the infection process. To survive inside the cells, the first process that C. trachomatis faces is the innate immune response. As the "sentry" of the body, mast cells attempt to engulf and remove C. trachomatis. Dendritic cells present antigen of C. trachomatis to the "commanders" (T cells) through MHC-I and MHC-II. IFN-γ produced by activated T cells and natural killer cells (NK) further activates macrophages. They form the body's "combat troops" and produce immunity against C. trachomatis in the tissues and blood. In addition, the role of eosinophils, basophils, innate lymphoid cells (ILCs), natural killer T (NKT) cells, γδT cells and B-1 cells should not be underestimated in the infection of C. trachomatis. The protective role of innate immunity is insufficient, and sexually transmitted diseases (STDs) caused by C. trachomatis infections tend to be insidious and recalcitrant. As a consequence, C. trachomatis has developed a unique evasion mechanism that triggers inflammatory immunopathology and acts as a bridge to protective to pathological adaptive immunity. This review focuses on the recent advances in how C. trachomatis evades various innate immune cells, which contributes to vaccine development and our understanding of the pathophysiologic consequences of C. trachomatis infection.
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Affiliation(s)
| | | | | | - Zhongyu Li
- Institute of Pathogenic Biology, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, School of Nursing, Hengyang Medical College, University of South China, Hengyang, China
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Dembek ZF, Mothershead JL, Owens AN, Chekol T, Wu A. Psittacosis: An Underappreciated and Often Undiagnosed Disease. Pathogens 2023; 12:1165. [PMID: 37764973 PMCID: PMC10536718 DOI: 10.3390/pathogens12091165] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/02/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
The bacterial agent Chlamydia psittaci, and the resulting disease of psittacosis, is a little-known and underappreciated infectious disease by healthcare practitioners and in public health in general. C. psittaci infections can cause significant psittacosis outbreaks, with person-to-person transmission documented in the last decade. In this publication, we review the pathogen and its disease, as well as examine the potential for genetic manipulation in this organism to create a more deadly pathogen. Recent disease surveys indicate that currently, the highest incidences of human disease exist in Australia, Germany and the UK. We recommend the universal public health reporting of C. psittaci and psittacosis disease and increasing the promotion of public health awareness.
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Affiliation(s)
- Zygmunt F. Dembek
- Battelle Memorial Institute, Support to DTRA Technical Reachback, Columbus, OH 43201, USA; (Z.F.D.); (T.C.)
| | - Jerry L. Mothershead
- Applied Research Associates (ARA), Support to DTRA Technical Reachback, Albuquerque, NM 87110, USA;
| | - Akeisha N. Owens
- Defense Threat Reduction Agency (DTRA), Fort Belvoir, VA 22060, USA;
| | - Tesema Chekol
- Battelle Memorial Institute, Support to DTRA Technical Reachback, Columbus, OH 43201, USA; (Z.F.D.); (T.C.)
| | - Aiguo Wu
- Defense Threat Reduction Agency (DTRA), Fort Belvoir, VA 22060, USA;
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DeBoer AG, Lei L, Yang C, Martens CA, Anzick SL, Antonioli-Schmit S, Suchland RJ, McClarty G, Caldwell HD, Rockey DD. TargeTron Inactivation of Chlamydia trachomatis gseA Results in a Lipopolysaccharide 3-Deoxy-d-Manno-Oct-2-Ulosonic Acid-Deficient Strain That Is Cytotoxic for Cells. Infect Immun 2023; 91:e0009623. [PMID: 37255490 PMCID: PMC10353364 DOI: 10.1128/iai.00096-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 03/17/2023] [Indexed: 06/01/2023] Open
Abstract
All members of the family Chlamydiaceae have lipopolysaccharides (LPS) that possess a shared carbohydrate trisaccharide antigen, 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) that is functionally uncharacterized. A single gene, genus-specific epitope (gseA), is responsible for attaching the tri-Kdo to lipid IVA. To investigate the function of Kdo in chlamydial host cell interactions, we made a gseA-null strain (L2ΔgseA) by using TargeTron mutagenesis. Immunofluorescence microscopy and immunoblotting with a Kdo-specific monoclonal antibody demonstrated that L2ΔgseA lacked Kdo. L2ΔgseA reacted by immunoblotting with a monoclonal antibody specific for a conserved LPS glucosamine-PO4 epitope, indicating that core lipid A was retained by the mutant. The mutant strain produced a similar number of inclusions as the parental strain but yielded lower numbers of infectious elementary bodies. Transmission electron microscopy of L2ΔgseA-infected cells showed atypical developmental forms and a reduction in the number of elementary bodies. Immunoblotting of dithiothreitol-treated L2ΔgseA-infected cells lysates revealed a marked reduction in outer membrane OmcB disulfide cross-linking, suggesting that the elementary body outer membrane structure was affected by the lack of Kdo. Notably, lactic acid dehydrogenase release by infected cells demonstrated that L2ΔgseA was significantly more cytotoxic to host cells than the wild type. The cytotoxic phenotype may result from an altered outer membrane biogenesis structure and/or function or, conversely, from a direct pathobiological effect of Kdo on an unknown host cell target. These findings implicate a previously unrecognized role for Kdo in host cell interactions that facilitates postinfection host cell survival.
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Affiliation(s)
- Addison G. DeBoer
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Lei Lei
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Chunfu Yang
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Craig A. Martens
- National Institute of Allergy and Infectious Disease, Rocky Mountain Laboratory, Hamilton, Montana, USA
| | - Sarah L. Anzick
- National Institute of Allergy and Infectious Disease, Rocky Mountain Laboratory, Hamilton, Montana, USA
| | - Sophia Antonioli-Schmit
- National Institute of Allergy and Infectious Disease, Rocky Mountain Laboratory, Hamilton, Montana, USA
| | - Robert J. Suchland
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington
| | - Grant McClarty
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba Winnipeg, Winnipeg, Manitoba, Canada
| | - Harlan D. Caldwell
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Daniel D. Rockey
- Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon, USA
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Sixt BS. Host cell death during infection with Chlamydia: a double-edged sword. FEMS Microbiol Rev 2021; 45:5902849. [PMID: 32897321 PMCID: PMC7794043 DOI: 10.1093/femsre/fuaa043] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/02/2020] [Indexed: 12/12/2022] Open
Abstract
The phylum Chlamydiae constitutes a group of obligate intracellular bacteria that infect a remarkably diverse range of host species. Some representatives are significant pathogens of clinical or veterinary importance. For instance, Chlamydia trachomatis is the leading infectious cause of blindness and the most common bacterial agent of sexually transmitted diseases. Chlamydiae are exceptionally dependent on their eukaryotic host cells as a consequence of their developmental biology. At the same time, host cell death is an integral part of the chlamydial infection cycle. It is therefore not surprising that the bacteria have evolved exquisite and versatile strategies to modulate host cell survival and death programs to their advantage. The recent introduction of tools for genetic modification of Chlamydia spp., in combination with our increasing awareness of the complexity of regulated cell death in eukaryotic cells, and in particular of its connections to cell-intrinsic immunity, has revived the interest in this virulence trait. However, recent advances also challenged long-standing assumptions and highlighted major knowledge gaps. This review summarizes current knowledge in the field and discusses possible directions for future research, which could lead us to a deeper understanding of Chlamydia's virulence strategies and may even inspire novel therapeutic approaches.
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Affiliation(s)
- Barbara S Sixt
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden
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