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Trouillon J, Attrée I, Elsen S. The regulation of bacterial two-partner secretion systems. Mol Microbiol 2023; 120:159-177. [PMID: 37340956 DOI: 10.1111/mmi.15112] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 06/01/2023] [Accepted: 06/07/2023] [Indexed: 06/22/2023]
Abstract
Two-partner secretion (TPS) systems, also known as Type Vb secretion systems, allow the translocation of effector proteins across the outer membrane of Gram-negative bacteria. By secreting different classes of effectors, including cytolysins and adhesins, TPS systems play important roles in bacterial pathogenesis and host interactions. Here, we review the current knowledge on TPS systems regulation and highlight specific and common regulatory mechanisms across TPS functional classes. We discuss in detail the specific regulatory networks identified in various bacterial species and emphasize the importance of understanding the context-dependent regulation of TPS systems. Several regulatory cues reflecting host environment during infection, such as temperature and iron availability, are common determinants of expression for TPS systems, even across relatively distant species. These common regulatory pathways often affect TPS systems across subfamilies with different effector functions, representing conserved global infection-related regulatory mechanisms.
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Affiliation(s)
- Julian Trouillon
- Université Grenoble Alpes, CNRS, CEA, IBS UMR 5075, Team Bacterial Pathogenesis and Cellular Responses, Grenoble, France
| | - Ina Attrée
- Université Grenoble Alpes, CNRS, CEA, IBS UMR 5075, Team Bacterial Pathogenesis and Cellular Responses, Grenoble, France
| | - Sylvie Elsen
- Université Grenoble Alpes, CNRS, CEA, IBS UMR 5075, Team Bacterial Pathogenesis and Cellular Responses, Grenoble, France
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2
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Siggins MK, MacLennan CA. An adsorption method to prepare specific antibody-depleted normal human serum as a source of complement for human serum bactericidal assays for Salmonella. Vaccine 2021; 39:7503-7509. [PMID: 34794820 DOI: 10.1016/j.vaccine.2021.10.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 10/08/2021] [Accepted: 10/11/2021] [Indexed: 10/19/2022]
Abstract
Serum bactericidal assays (SBA) are valuable for assessing the functional activity of natural and vaccine-induced antibodies against many Gram-negative bacteria, such as meningococcus and Salmonella. However, SBA often require an exogenous source of complement and the presence of pre-existing naturally acquired antibodies limits the use of human complement for this purpose. To remove pre-existing Salmonella-specific antibodies, in the context of SBA for Salmonella vaccine research, we incubated human sera with preparations of Salmonella. By incubating at 4 °C, pre-existing antibodies were adsorbed onto the Salmonella bacteria with only minimal complement deposition. We assessed the effects of adsorption on specific antibody levels, complement activity and the bactericidal activity of sera using flow cytometry, SBA and haemolytic assays. Adsorption removed Salmonella-specific antibodies and bactericidal activity against Salmonella from whole serum but was not detrimental to serum complement activity, even after five adsorption cycles. Bactericidal activity could be reconstituted in the adsorbed serum by the addition of exogenous specific antibodies. Sera preadsorbed with Salmonella are suitable as a source of human complement to measure the bactericidal activity of Salmonella antibodies. The adsorption method can be used to deplete, simply and rapidly, specific antibodies from serum to prepare a source of human complement for use in SBA for vaccine research and assessment.
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Affiliation(s)
- Matthew K Siggins
- The Institute of Immunology and Immunotherapy, University of Birmingham, B15 2TT, United Kingdom; National Heart and Lung Institute, St Mary's Hospital, Faculty of Medicine, Imperial College London, W2 1PG, United Kingdom.
| | - Calman A MacLennan
- The Institute of Immunology and Immunotherapy, University of Birmingham, B15 2TT, United Kingdom; The Jenner Institute, Nuffield Department of Medicine, University of Oxford, OX3 7DQ, United Kingdom; Bill & Melinda Gates Foundation, 62 Buckingham Gate, London SW1E 6AJ, United Kingdom.
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Muruganandah V, Kupz A. Immune responses to bacterial lung infections and their implications for vaccination. Int Immunol 2021; 34:231-248. [PMID: 34850883 DOI: 10.1093/intimm/dxab109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 11/28/2021] [Indexed: 11/14/2022] Open
Abstract
The pulmonary immune system plays a vital role in protecting the delicate structures of gaseous exchange against invasion from bacterial pathogens. With antimicrobial resistance becoming an increasing concern, finding novel strategies to develop vaccines against bacterial lung diseases remains a top priority. In order to do so, a continued expansion of our understanding of the pulmonary immune response is warranted. Whilst some aspects are well characterised, emerging paradigms such as the importance of innate cells and inducible immune structures in mediating protection provide avenues of potential to rethink our approach to vaccine development. In this review, we aim to provide a broad overview of both the innate and adaptive immune mechanisms in place to protect the pulmonary tissue from invading bacterial organisms. We use specific examples from several infection models and human studies to depict the varying functions of the pulmonary immune system that may be manipulated in future vaccine development. Particular emphasis has been placed on emerging themes that are less reviewed and underappreciated in vaccine development studies.
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Affiliation(s)
- Visai Muruganandah
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD 4878, Australia
| | - Andreas Kupz
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD 4878, Australia
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Kadry NA, Porsch EA, Shen H, St Geme JW. Immunization with HMW1 and HMW2 adhesins protects against colonization by heterologous strains of nontypeable Haemophilus influenzae. Proc Natl Acad Sci U S A 2021; 118:e2019923118. [PMID: 34344825 PMCID: PMC8364133 DOI: 10.1073/pnas.2019923118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is a common cause of localized respiratory tract disease and results in significant morbidity. The pathogenesis of NTHi disease begins with nasopharyngeal colonization, and therefore, the prevention of colonization represents a strategy to prevent disease. The NTHi HMW1 and HMW2 proteins are a family of conserved adhesins that are present in 75 to 80% of strains and have been demonstrated to play a critical role in colonization of the upper respiratory tract in rhesus macaques. In this study, we examined the vaccine potential of HMW1 and HMW2 using a mouse model of nasopharyngeal colonization. Immunization with HMW1 and HMW2 by either the subcutaneous or the intranasal route resulted in a strain-specific antibody response associated with agglutination of bacteria and restriction of bacterial adherence. Despite the specificity of the antibody response, immunization resulted in protection against colonization by both the parent NTHi strain and heterologous strains expressing distinct HMW1 and HMW2 proteins. Pretreatment with antibody against IL-17A eliminated protection against heterologous strains, indicating that heterologous protection is IL-17A dependent. This work demonstrates the vaccine potential of the HMW1 and HMW2 proteins and highlights the importance of IL-17A in protection against diverse NTHi strains.
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Affiliation(s)
- Nadia A Kadry
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
| | - Eric A Porsch
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104
| | - Hao Shen
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
- Shanghai Institute of Immunology, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China
| | - Joseph W St Geme
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104;
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104
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Alderson MR, Murphy T, Pelton SI, Novotny LA, Hammitt LL, Kurabi A, Li JD, Thornton RB, Kirkham LAS. Panel 8: Vaccines and immunology. Int J Pediatr Otorhinolaryngol 2020; 130 Suppl 1:109839. [PMID: 31948716 PMCID: PMC7153269 DOI: 10.1016/j.ijporl.2019.109839] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE To review and highlight significant advances made towards vaccine development and understanding of the immunology of otitis media (OM) since the 19th International Symposium on Recent Advances in Otitis Media (ISOM) in 2015, as well as identify future research directions and knowledge gaps. DATA SOURCES PubMed database, National Library of Medicine. REVIEW METHODS Key topics were assigned to each panel member for detailed review. Draft reviews were collated, circulated, and thoroughly discussed when the panel met at the 20th ISOM in June 2019. The final manuscript was prepared with input from all panel members. CONCLUSIONS Since 2015 there have been a number of studies assessing the impact of licensed pneumococcal vaccines on OM. While these studies have confirmed that these vaccines are effective in preventing carriage and/or disease caused by vaccine serotypes, OM caused by non-vaccine serotype pneumococci and other otopathogens remains a significant health care burden globally. Development of multi-species vaccines is challenging but essential to reducing the global burden of OM. Influenza vaccination has been shown to prevent acute OM, and with novel vaccines against nontypeable Haemophilus influenzae (NTHi), Moraxella catarrhalis and Respiratory Syncytial Virus (RSV) in clinical trials, the potential to significantly prevent OM is within reach. Research into alternative vaccine delivery strategies has demonstrated the power of maternal and mucosal vaccination for OM prevention. Future OM vaccine trials must include molecular diagnostics of middle ear effusion, for detection of viruses and bacteria that are persisting in biofilms and to enable accurate assessment of vaccine impact on OM etiology. Understanding population differences in natural and vaccine-induced immune responses to otopathogens is also important for development of the most effective OM vaccines. Improved understanding of the interaction between otopathogens will also advance development of effective therapies and encourage the assessment of the indirect benefits of vaccination. IMPLICATIONS FOR PRACTICE While NTHi and M. catarrhalis are the predominant otopathogens, funding opportunities to drive vaccine development for these species are limited due to a focus on prevention of childhood mortality rather than morbidity. Delivery of a comprehensive report on the high financial and social costs of OM, including the potential for OM vaccines to reduce antibiotic use and subsequent development of antimicrobial resistance (AMR), would likely assist in engaging stakeholders to recognize the value of prevention of OM and increase support for efforts on OM vaccine development. Vaccine trials with OM prevention as a clinical end-point are challenging, however a focus on developing assays that measure functional correlates of protection would facilitate OM vaccine development.
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Affiliation(s)
| | - Tim Murphy
- Clinical and Translational Research Center, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Stephen I Pelton
- Boston University School of Public Health, Boston University, Boston, MA, USA
| | - Laura A Novotny
- The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Laura L Hammitt
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Arwa Kurabi
- Division of Otolaryngology, Department of Surgery, University of California, San Diego, CA, USA
| | - Jian-Dong Li
- Center for Inflammation, Immunity & Infection, Institute for Biomedical Sciences, Georgia State University, GA, USA
| | - Ruth B Thornton
- School of Biomedical Sciences, University of Western Australia, Australia and Wesfarmers Centre for Vaccines and Infectious Diseases Research, Telethon Kids Institute, Perth, Australia
| | - Lea-Ann S Kirkham
- Wesfarmers Centre for Vaccines and Infectious Diseases Research, Telethon Kids Institute, Australia and Centre for Child Health Research, University of Western Australia, Perth, Australia
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HMW1555-914, HMW2553-916, and Hia585-705 as Subunit Vaccine Candidates of Nontypeable Haemophilus influenzae Induce Specific Antibody Responses with Bactericidal Activity in Balb/c. Jundishapur J Microbiol 2017. [DOI: 10.5812/jjm.58329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Immunogenicity of Nontypeable Haemophilus influenzae Outer Membrane Vesicles and Protective Ability in the Chinchilla Model of Otitis Media. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2017; 24:CVI.00138-17. [PMID: 28768669 DOI: 10.1128/cvi.00138-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 07/31/2017] [Indexed: 12/22/2022]
Abstract
Outer membrane vesicles (OMVs) produced by Gram-negative bacteria are enriched in several outer membrane components, including major and minor outer membrane proteins and lipooligosaccharide. We assessed the functional activity of nontypeable Haemophilus influenzae (NTHi) OMV-specific antisera and the protective ability of NTHi OMVs as vaccine antigens in the chinchilla otitis media model. OMVs were purified from three HMW1/HMW2-expressing NTHi strains, two of which were also engineered to overexpress Hia proteins. OMV-specific antisera raised in guinea pigs were assessed for their ability to mediate killing of representative NTHi in an opsonophagocytic assay. The three OMV-specific antisera mediated killing of 18 of 65, 24 of 65, and 30 of 65 unrelated HMW1/HMW2-expressing NTHi strains. Overall, they mediated killing of 39 of 65 HMW1/HMW2-expressing strains. The two Hia-expressing OMV-specific antisera mediated killing of 17 of 25 and 14 of 25 unrelated Hia-expressing NTHi strains. Overall, they mediated killing of 20 of 25 Hia-expressing strains. OMVs from prototype NTHi strain 12 were used to immunize chinchillas and the course of middle ear infection was monitored following intrabullar challenge with the homologous strain. All control animals developed culture-positive otitis media, as did two of three HMW1/HMW2-immunized animals. All OMV-immunized animals, with or without supplemental HMW1/HMW2 immunization, were completely protected against otitis media. NTHi OMVs are the first immunogens examined in this model that provided complete protection with sterile immunity after NTHi strain 12 challenge. These data suggest that NTHi OMVs hold significant potential as components of protective NTHi vaccines, possibly in combination with HMW1/HMW2 proteins.
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Ahearn CP, Gallo MC, Murphy TF. Insights on persistent airway infection by non-typeable Haemophilus influenzae in chronic obstructive pulmonary disease. Pathog Dis 2017; 75:3753446. [PMID: 28449098 PMCID: PMC5437125 DOI: 10.1093/femspd/ftx042] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 04/28/2017] [Indexed: 12/21/2022] Open
Abstract
Non-typeable Haemophilus influenzae (NTHi) is the most common bacterial cause of infection of the lower airways in adults with chronic obstructive pulmonary disease (COPD). Infection of the COPD airways causes acute exacerbations, resulting in substantial morbidity and mortality. NTHi has evolved multiple mechanisms to establish infection in the hostile environment of the COPD airways, allowing the pathogen to persist in the airways for months to years. Persistent infection of the COPD airways contributes to chronic airway inflammation that increases symptoms and accelerates the progressive loss of pulmonary function, which is a hallmark of the disease. Persistence mechanisms of NTHi include the expression of multiple redundant adhesins that mediate binding to host cellular and extracellular matrix components. NTHi evades host immune recognition and clearance by invading host epithelial cells, forming biofilms, altering gene expression and displaying surface antigenic variation. NTHi also binds host serum factors that confer serum resistance. Here we discuss the burden of COPD and the role of NTHi infections in the course of the disease. We provide an overview of NTHi mechanisms of persistence that allow the pathogen to establish a niche in the hostile COPD airways.
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Affiliation(s)
- Christian P. Ahearn
- Department of Microbiology and Immunology, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
- Clinical and Translational Research Center, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
| | - Mary C. Gallo
- Department of Microbiology and Immunology, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
- Clinical and Translational Research Center, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
| | - Timothy F. Murphy
- Department of Microbiology and Immunology, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
- Clinical and Translational Research Center, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
- Division of Infectious Disease, Department of Medicine, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
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