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Melo RCN, Silva TP. Eosinophil activation during immune responses: an ultrastructural view with an emphasis on viral diseases. J Leukoc Biol 2024; 116:321-334. [PMID: 38466831 DOI: 10.1093/jleuko/qiae058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 02/17/2024] [Accepted: 02/21/2024] [Indexed: 03/13/2024] Open
Abstract
Eosinophils are cells of the innate immune system that orchestrate complex inflammatory responses. The study of the cell biology of eosinophils, particularly associated with cell activation, is of great interest to understand their immune responses. From a morphological perspective, activated eosinophils show ultrastructural signatures that have provided critical insights into the comprehension of their functional capabilities. Application of conventional transmission electron microscopy in combination with quantitative assessments (quantitative transmission electron microscopy), molecular imaging (immunoEM), and 3-dimensional electron tomography have generated important insights into mechanisms of eosinophil activation. This review explores a multitude of ultrastructural events taking place in eosinophils activated in vitro and in vivo as key players in allergic and inflammatory diseases, with an emphasis on viral infections. Recent progress in our understanding of biological processes underlying eosinophil activation, including in vivo mitochondrial remodeling, is discussed, and it can bring new thinking to the field.
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Affiliation(s)
- Rossana C N Melo
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora (UFJF), Rua José Lourenço Kelmer, campus, Juiz de Fora, MG, 36036-900, Brazil
| | - Thiago P Silva
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora (UFJF), Rua José Lourenço Kelmer, campus, Juiz de Fora, MG, 36036-900, Brazil
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2
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Agac A, Kolbe SM, Ludlow M, Osterhaus ADME, Meineke R, Rimmelzwaan GF. Host Responses to Respiratory Syncytial Virus Infection. Viruses 2023; 15:1999. [PMID: 37896776 PMCID: PMC10611157 DOI: 10.3390/v15101999] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 09/22/2023] [Accepted: 09/23/2023] [Indexed: 10/29/2023] Open
Abstract
Respiratory syncytial virus (RSV) infections are a constant public health problem, especially in infants and older adults. Virtually all children will have been infected with RSV by the age of two, and reinfections are common throughout life. Since antigenic variation, which is frequently observed among other respiratory viruses such as SARS-CoV-2 or influenza viruses, can only be observed for RSV to a limited extent, reinfections may result from short-term or incomplete immunity. After decades of research, two RSV vaccines were approved to prevent lower respiratory tract infections in older adults. Recently, the FDA approved a vaccine for active vaccination of pregnant women to prevent severe RSV disease in infants during their first RSV season. This review focuses on the host response to RSV infections mediated by epithelial cells as the first physical barrier, followed by responses of the innate and adaptive immune systems. We address possible RSV-mediated immunomodulatory and pathogenic mechanisms during infections and discuss the current vaccine candidates and alternative treatment options.
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Affiliation(s)
| | | | | | | | | | - Guus F. Rimmelzwaan
- Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; (A.A.); (S.M.K.); (M.L.); (A.D.M.E.O.); (R.M.)
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3
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Wellemans V, Benhassou HA, Fuselier E, Bellesort F, Dury S, Lebargy F, Dormoy V, Fichel C, Naour RL, Gounni AS, Lamkhioued B. Role of CCR3 in respiratory syncytial virus infection of airway epithelial cells. iScience 2021; 24:103433. [PMID: 34917892 PMCID: PMC8646169 DOI: 10.1016/j.isci.2021.103433] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 08/29/2021] [Accepted: 11/10/2021] [Indexed: 01/17/2023] Open
Abstract
Respiratory syncytial virus (RSV) infection is the principal cause of severe lower respiratory tract disease and accounts for a significant risk for developing asthma later in life. Clinical studies have shown an increase in airway responsiveness and a concomitant Th2 response in the lungs of RSV-infected patients. These indications suggest that RSV may modulate aspects of the immune response to promote virus replication. Here, we show that CCR3 facilitates RSV infection of airway epithelial cells, an effect that was inhibited by eotaxin-1/CCL11 or upon CCR3 gene silencing. Mechanistically, cellular entry of RSV is mediated by binding of the viral G protein to CCR3 and selective chemotaxis of Th2 cells and eosinophils. In vivo, mice lacking CCR3 display a significant reduction in RSV infection, airway inflammation, and mucus production. Overall, RSV G protein-CCR3 interaction may participate in pulmonary infection and inflammation by enhancing eosinophils' recruitment and less potent antiviral Th2 cells. CCR3 mediates RSV infection of human airway epithelial cells Eotaxin-1 blocks RSV-G binding to CCR3 and significantly decreases RSV infection RSV-G secreted protein (sG) attracts human eosinophils and Th2 cells through CCR3 RSV infection of mice lacking CCR3 exhibited reduced inflammation and mucus secretion
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Affiliation(s)
| | - Hassan Ait Benhassou
- Laboratoire d'Immunologie et de Biotechnologie, EA7509-IRMAIC, Pôle-Santé, Université de Reims Champagne-Ardenne, Reims, France
| | - Eloise Fuselier
- Laboratoire d'Immunologie et de Biotechnologie, EA7509-IRMAIC, Pôle-Santé, Université de Reims Champagne-Ardenne, Reims, France
| | | | - Sandra Dury
- Laboratoire d'Immunologie et de Biotechnologie, EA7509-IRMAIC, Pôle-Santé, Université de Reims Champagne-Ardenne, Reims, France.,Service des Maladies Respiratoires et Allergiques. Hôpital Maison Blanche, CHU de Reims, Reims, France
| | - François Lebargy
- Laboratoire d'Immunologie et de Biotechnologie, EA7509-IRMAIC, Pôle-Santé, Université de Reims Champagne-Ardenne, Reims, France.,Service des Maladies Respiratoires et Allergiques. Hôpital Maison Blanche, CHU de Reims, Reims, France
| | - Valérian Dormoy
- Inserm UMR-S 1250, Pathologies Pulmonaires et Plasticité Cellulaire (P3Cell). Université de Reims Champagne-Ardenne, Reims, France
| | - Caroline Fichel
- Laboratoire d'Immunologie et de Biotechnologie, EA7509-IRMAIC, Pôle-Santé, Université de Reims Champagne-Ardenne, Reims, France
| | - Richard Le Naour
- Laboratoire d'Immunologie et de Biotechnologie, EA7509-IRMAIC, Pôle-Santé, Université de Reims Champagne-Ardenne, Reims, France
| | - Abdelilah S Gounni
- Department of Immunology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Canada
| | - Bouchaib Lamkhioued
- Laboratoire d'Immunologie et de Biotechnologie, EA7509-IRMAIC, Pôle-Santé, Université de Reims Champagne-Ardenne, Reims, France
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4
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van Erp EA, Luytjes W, Ferwerda G, van Kasteren PB. Fc-Mediated Antibody Effector Functions During Respiratory Syncytial Virus Infection and Disease. Front Immunol 2019; 10:548. [PMID: 30967872 PMCID: PMC6438959 DOI: 10.3389/fimmu.2019.00548] [Citation(s) in RCA: 175] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 02/28/2019] [Indexed: 12/20/2022] Open
Abstract
Respiratory syncytial virus (RSV) is a major cause of severe lower respiratory tract infections and hospitalization in infants under 1 year of age and there is currently no market-approved vaccine available. For protection against infection, young children mainly depend on their innate immune system and maternal antibodies. Traditionally, antibody-mediated protection against viral infections is thought to be mediated by direct binding of antibodies to viral particles, resulting in virus neutralization. However, in the case of RSV, virus neutralization titers do not provide an adequate correlate of protection. The current lack of understanding of the mechanisms by which antibodies can protect against RSV infection and disease or, alternatively, contribute to disease severity, hampers the design of safe and effective vaccines against this virus. Importantly, neutralization is only one of many mechanisms by which antibodies can interfere with viral infection. Antibodies consist of two structural regions: a variable fragment (Fab) that mediates antigen binding and a constant fragment (Fc) that mediates downstream effector functions via its interaction with Fc-receptors on (innate) immune cells or with C1q, the recognition molecule of the complement system. The interaction with Fc-receptors can lead to killing of virus-infected cells through a variety of immune effector mechanisms, including antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP). Antibody-mediated complement activation may lead to complement-dependent cytotoxicity (CDC). In addition, both Fc-receptor interactions and complement activation can exert a broad range of immunomodulatory functions. Recent studies have emphasized the importance of Fc-mediated antibody effector functions in both protection and pathogenesis for various infectious agents. In this review article, we aim to provide a comprehensive overview of the current knowledge on Fc-mediated antibody effector functions in the context of RSV infection, discuss their potential role in establishing the balance between protection and pathogenesis, and point out important gaps in our understanding of these processes. Furthermore, we elaborate on the regulation of these effector functions on both the cellular and humoral side. Finally, we discuss the implications of Fc-mediated antibody effector functions for the rational design of safe and effective vaccines and monoclonal antibody therapies against RSV.
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Affiliation(s)
- Elisabeth A. van Erp
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
- Section Pediatric Infectious Diseases, Laboratory of Medical Immunology, Radboud Institute for Molecular Life Sciences, Nijmegen, Netherlands
- Radboud Center for Infectious Diseases, Nijmegen, Netherlands
| | - Willem Luytjes
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
| | - Gerben Ferwerda
- Section Pediatric Infectious Diseases, Laboratory of Medical Immunology, Radboud Institute for Molecular Life Sciences, Nijmegen, Netherlands
- Radboud Center for Infectious Diseases, Nijmegen, Netherlands
| | - Puck B. van Kasteren
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
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5
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Bohmwald K, Espinoza JA, Pulgar RA, Jara EL, Kalergis AM. Functional Impairment of Mononuclear Phagocyte System by the Human Respiratory Syncytial Virus. Front Immunol 2017; 8:1643. [PMID: 29230219 PMCID: PMC5712212 DOI: 10.3389/fimmu.2017.01643] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 11/10/2017] [Indexed: 12/18/2022] Open
Abstract
The mononuclear phagocyte system (MPS) comprises of monocytes, macrophages (MΦ), and dendritic cells (DCs). MPS is part of the first line of immune defense against a wide range of pathogens, including viruses, such as the human respiratory syncytial virus (hRSV). The hRSV is an enveloped virus that belongs to the Pneumoviridae family, Orthopneumovirus genus. This virus is the main etiological agent causing severe acute lower respiratory tract infection, especially in infants, children and the elderly. Human RSV can cause bronchiolitis and pneumonia and it has also been implicated in the development of recurrent wheezing and asthma. Monocytes, MΦ, and DCs significantly contribute to acute inflammation during hRSV-induced bronchiolitis and asthma exacerbation. Furthermore, these cells seem to be an important component for the association between hRSV and reactive airway disease. After hRSV infection, the first cells encountered by the virus are respiratory epithelial cells, alveolar macrophages (AMs), DCs, and monocytes in the airways. Because AMs constitute the predominant cell population at the alveolar space in healthy subjects, these cells work as major innate sentinels for the recognition of pathogens. Although adaptive immunity is crucial for viral clearance, AMs are required for the early immune response against hRSV, promoting viral clearance and controlling immunopathology. Furthermore, exposure to hRSV may affect the phagocytic and microbicidal capacity of monocytes and MΦs against other infectious agents. Finally, different studies have addressed the roles of different DC subsets during infection by hRSV. In this review article, we discuss the role of the lung MPS during hRSV infection and their involvement in the development of bronchiolitis.
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Affiliation(s)
- Karen Bohmwald
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Janyra A Espinoza
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Raúl A Pulgar
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Evelyn L Jara
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alexis M Kalergis
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Endocrinología, Facultad de Medicina, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
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6
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Farrag MA, Almajhdi FN. Human Respiratory Syncytial Virus: Role of Innate Immunity in Clearance and Disease Progression. Viral Immunol 2015; 29:11-26. [PMID: 26679242 DOI: 10.1089/vim.2015.0098] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Human respiratory syncytial virus (HRSV) infections have worldwide records. The virus is responsible for bronchiolitis, pneumonia, and asthma in humans of different age groups. Premature infants, young children, and immunocompromised individuals are prone to severe HRSV infection that may lead to death. Based on worldwide estimations, millions of cases were reported in both developed and developing countries. In fact, HRSV symptoms develop mainly as a result of host immune response. Due to inability to establish long lasting adaptive immunity, HRSV infection is recurrent and hence impairs vaccine development. Once HRSV attached to the airway epithelia, interaction with the host innate immune components starts. HRSV interaction with pulmonary innate defenses is crucial in determining the disease outcome. Infection of alveolar epithelial cells triggers a cascade of events that lead to recruitment and activation of leukocyte populations. HRSV clearance is mediated by a number of innate leukocytes, including macrophages, natural killer cells, eosinophils, dendritic cells, and neutrophils. Regulation of these cells is mediated by cytokines, chemokines, and other immune mediators. Although the innate immune system helps to clear HRSV infection, it participates in disease progression such as bronchiolitis and asthma. Resolving the mechanisms by which HRSV induces pathogenesis, different possible interactions between the virus and immune components, and immune cells interplay are essential for developing new effective vaccines. Therefore, the current review focuses on how the pulmonary innate defenses mediate HRSV clearance and to what extent they participate in disease progression. In addition, immune responses associated with HRSV vaccines will be discussed.
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Affiliation(s)
- Mohamed A Farrag
- Department of Botany and Microbiology, King Saud University , Riyadh, Saudi Arabia
| | - Fahad N Almajhdi
- Department of Botany and Microbiology, King Saud University , Riyadh, Saudi Arabia
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7
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Eosinophils and Anti-Pathogen Host Defense. EOSINOPHILS IN HEALTH AND DISEASE 2013. [PMCID: PMC7156009 DOI: 10.1016/b978-0-12-394385-9.00009-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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8
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Effects of respiratory syncytial virus infection and major basic protein derived from eosinophils in pulmonary alveolar epithelial cells (A549). Cell Biol Int 2011; 35:467-74. [PMID: 20977431 DOI: 10.1042/cbi20100255] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
RSV (respiratory syncytial virus)-induced pneumonia and bronchiolitis may be associated with hyperresponsive conditions, including asthma. Eosinophilic proteins such as MBP (major basic protein) may also be associated with the pathophysiology of asthma. To elucidate the roles of RSV infection and MBP in the pathogenesis of pneumonia with hyperresponsiveness, we investigated the effects of RSV infection and MBP on A549 (alveolar epithelial) cells. CPE (cytopathic effects) in A549 cells were observed by microscopy. Apoptosis and cell death was evaluated by flow cytometric analysis and modified MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. We also measured 15 types of cytokines and chemokines in A549 cell supernatants. Although RSV alone did not affect the CPE of A549, high concentrations of MBP resulted in cell death within 24 h. Combinations of RSV and MBP synergistically induced cell death. In A549 cells infected with RSV alone, the release of GM-CSF (granulocyte-macrophage colony-stimulating factor) was significantly enhanced compared with control cells (no infection). In the cells treated with MBP alone, the production of IL (interleukin)-2, 4, 5, 7, 10, 12, 13, 17, IFN (interferon)-γ, GM-CSF, G-CSF (granulocyte colony-stimulating factor) and MIP (macrophage inflammatory protein)-1β was significantly increased compared with control cells. Notably, the levels of GM-CSF and IL-17 in RSV/MBP-treated cells were significantly higher than those treated with MBP alone. These results suggest that MBP synergistically enhanced the release of various cytokines/chemokines and the cell death of RSV-infected A549 cells, indicating that MBP may be closely associated with the pathophysiology of allergic reactions in bronchiolitis/pneumonia due to RSV.
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9
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Kato M, Suzuki M, Hayashi Y, Kimura H. Role of eosinophils and their clinical significance in allergic inflammation. Expert Rev Clin Immunol 2010; 2:121-33. [PMID: 20477093 DOI: 10.1586/1744666x.2.1.121] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Eosinophils are believed to play roles in the pathophysiology of allergic inflammation, such as bronchial asthma. However, recent studies on anti-interleukin-5 monoclonal antibody treatment of asthmatic patients raised the possibility that eosinophils may play only a limited role. More recent studies established that eosinophils are essentially involved in the development of airway remodeling. Moreover, it is theoretically conceivable that eosinophils are a cellular source of lipid mediators, such as cysteinyl leukotrienes or platelet-activating factor in asthma. Even in the absence of interleukin-5, it is likely that the 'T-helper Type 2 network', including a cascade of vascular cell adhesion molecule-1, intercellular cell adhesion molecule-1, CC chemokines, granulocyte-macrophage colony-stimulating factor, for example, can maintain sufficient eosinophilic infiltration and effector functions, such as superoxide anion generation and degranulation. Long-term studies, wherein tissue eosinophils are eliminated effectively will be required to establish the exact roles of these cells in asthma. Finally, the authors will demonstrate that eosinophils have the potential for not only playing detrimental roles but also beneficial ones.
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Affiliation(s)
- Masahiko Kato
- Gunma Children's Medical Center, Department of Allergy and Immunology, Gunma Children's Medical Center, 779 Shimohakoda, Hokkitsu, Gunma 377-8577, Japan.
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10
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Pneumoviruses infect eosinophils and elicit MyD88-dependent release of chemoattractant cytokines and interleukin-6. Blood 2009; 114:2649-56. [PMID: 19652202 DOI: 10.1182/blood-2009-01-199497] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Eosinophils are recruited to the lung in response to infection with pneumovirus pathogens and have been associated with both the pathophysiologic sequelae of infection and, more recently, with accelerated virus clearance. Here, we demonstrate that the pneumovirus pathogens, respiratory syncytial virus (RSV) and pneumonia virus of mice (PVM), can infect human and mouse eosinophils, respectively, and that virus infection of eosinophils elicits the release of disease-related proinflammatory mediators from eosinophils. RSV replication in human eosinophils results in the release of infectious virions and in the release of the proinflammatory mediator, interleukin-6 (IL-6). PVM replication in cultured bone marrow eosinophils (bmEos) likewise results in release of infectious virions and the proinflammatory mediators IL-6, IP-10, CCL2, and CCL3. In contrast to the findings reported in lung tissue of RSV-challenged mice, PVM replication is accelerated in MyD88 gene-deleted bmEos, whereas release of cytokines is diminished. Interestingly, exogenous IL-6 suppresses virus replication in MyD88 gene-deleted bmEos, suggesting a role for a MyD88-dependent cytokine-mediated feedback circuit in modulating this response. Taken together, our findings suggest that eosinophils are targets of virus infection and may have varied and complex contributions to the pathogenesis and resolution of pneumovirus disease.
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Rosenberg HF, Dyer KD, Domachowske JB. Respiratory viruses and eosinophils: exploring the connections. Antiviral Res 2009; 83:1-9. [PMID: 19375458 PMCID: PMC2741084 DOI: 10.1016/j.antiviral.2009.04.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Revised: 04/06/2009] [Accepted: 04/09/2009] [Indexed: 01/12/2023]
Abstract
In this review, we consider the role played by eosinophilic leukocytes in the pathogenesis and pathophysiology of respiratory virus infection. The vast majority of the available information on this topic focuses on respiratory syncytial virus (RSV; Family Paramyxoviridae, genus Pneumovirus), an important pediatric pathogen that infects infants worldwide. There is no vaccine currently available for RSV. A formalin-inactivated RSV vaccine used in a trial in the 1960s elicited immunopathology in response to natural RSV infection; this has been modeled experimentally, primarily in inbred mice and cotton rats. Eosinophils are recruited to the lung tissue in response to formalin-inactivated RSV vaccine antigens in humans and in experimental models, but they may or may not be involved in promoting the severe clinical sequelae observed. Pulmonary eosinophilia elicited in response to primary RSV infection has also been explored; this response is particularly evident in the youngest human infants and in neonatal mouse models. Although pulmonary eosinophilia is nearly always perceived in a negative light, the specific role played by virus-elicited eosinophils - negative, positive or neutral bystander - remain unclear. Lastly, we consider the data that focus on the role of eosinophils in promoting virus clearance and antiviral host defense, and conclude with a recent study that explores the role of eosinophils themselves as targets of virus infection.
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Affiliation(s)
- Helene F Rosenberg
- Eosinophil Biology Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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Shinohara M, Wakiguchi H, Saito H, Matsumoto K. Presence of eosinophils in nasal secretion during acute respiratory tract infection in young children predicts subsequent wheezing within two months. Allergol Int 2008; 57:359-65. [PMID: 18797177 DOI: 10.2332/allergolint.o-08-544] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Accepted: 05/09/2008] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND In young children with wheezing or bronchiolitis, especially with respiratory syncitial virus, blood eosinophilia and a high eosinophil cationic protein level in nasal secretions predicts subsequent wheezing in later childhood. However, whether eosinophil activation results from virus-induced inflammation or local eosinophilia per se precedes the onset of wheezing remains unknown. In the present study, we examined the association between the presence of nasal eosinophils during respiratory tract infection (RTI) and subsequent wheezing in young children. METHODS A total of 35 young children less than 3 years of age who visited our outpatient clinic with rhinorrhea between April and July 2004 were enrolled in this prospective cohort study. Subjects who were given diagnoses of allergic rhinitis were excluded. In all the subjects, the presence of eosinophils in nasal secretions was determined. The subjects were followed, and the cumulative incidences of wheezing during the subsequent 2- and 12-month periods were examined. RESULTS According to a logistic regression analysis adjusted for age, sex, family history, allergies, and wheezing at entry, young children with nasal eosinophil infiltration during acute RTI had a significantly higher risk of wheezing during the subsequent 2 months, compared with those without nasal eosinophil infiltration (adjusted odds ratio, 27.618, p = 0.016). CONCLUSIONS Our findings not only suggest that nasal eosinophil testing may serve as a convenient clinical marker for identifying young children at risk for subsequent wheezing, but also shed new light on the role of eosinophils in the onset of wheezing in young children.
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Affiliation(s)
- Miwa Shinohara
- Department of Pediatrics, Kochi Medical School, Kochi, Japan
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13
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Dyer KD, Moser JM, Czapiga M, Siegel SJ, Percopo CM, Rosenberg HF. Functionally competent eosinophils differentiated ex vivo in high purity from normal mouse bone marrow. THE JOURNAL OF IMMUNOLOGY 2008; 181:4004-9. [PMID: 18768855 DOI: 10.4049/jimmunol.181.6.4004] [Citation(s) in RCA: 215] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
We have devised an ex vivo culture system which generates large numbers of eosinophils at high purity (>90%) from unselected mouse bone marrow progenitors. In response to 4 days of culture with recombinant mouse FLT3-L and recombinant mouse stem cell factor followed by recombinant mouse IL-5 alone thereafter, the resulting bone marrow-derived eosinophils (bmEos) express immunoreactive major basic protein, Siglec F, IL-5R alpha-chain, and transcripts encoding mouse eosinophil peroxidase, CCR3, the IL-3/IL-5/GM-CSF receptor common beta-chain, and the transcription factor GATA-1. BmEos are functionally competent: they undergo chemotaxis toward mouse eotaxin-1 and produce characteristic cytokines, including IFN-gamma, IL-4, MIP-1alpha, and IL-6. The rodent pathogen pneumonia virus of mice replicates in bmEos and elevated levels of IL-6 are detected in supernatants of bmEos cultures in response to active infection. Finally, differentiating bmEos are readily transfected with lentiviral vectors, suggesting a means for rapid production of genetically manipulated cells.
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Affiliation(s)
- Kimberly D Dyer
- Eosinophil Biology Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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14
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Asthma. PEDIATRIC ALLERGY, ASTHMA AND IMMUNOLOGY 2008. [PMCID: PMC7120610 DOI: 10.1007/978-3-540-33395-1_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Asthma has been recognized as a disease since the earliest times. In the Corpus Hippocraticum, Hippocrates used the term “ασθμα” to indicate any form of breathing difficulty manifesting itself by panting. Aretaeus of Cappadocia, a well-known Greek physician (second century A.D.), is credited with providing the first detailed description of an asthma attack [13], and to Celsus it was a disease with wheezing and noisy, violent breathing. In the history of Rome, we find many members of the Julio-Claudian family affected with probable atopic respiratory disorders: Caesar Augustus suffered from bronchoconstriction, seasonal rhinitis as well as a highly pruritic skin disease. Claudius suffered from rhinoconjunctivitis and Britannicus was allergic to horse dander [529]. Maimonides (1136–1204) warned that to neglect treatment of asthma could prove fatal, whereas until the 19th century, European scholars defined it as “nervous asthma,” a term that was given to mean a defect of conductivity of the ninth pair of cranial nerves.
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Glass WG, Sarisky RT, Vecchio AMD. Not-so-sweet sixteen: the role of IL-16 in infectious and immune-mediated inflammatory diseases. J Interferon Cytokine Res 2006; 26:511-20. [PMID: 16881862 DOI: 10.1089/jir.2006.26.511] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Over the past two decades, our understanding of interleukin-16 (IL-16) has increased substantially. Initial studies characterizing IL-16 as a chemotactic cytokine (but not a chemokine) just scratched the surface of the unique properties of this cytokine. Since then, scientists have determined that IL-16 has a wide range of effects on cells, including upregulation of CD25, induction of cells to progress to the G(1) phase, inhibition of antigen- specific proliferation yet with retained antigen nonspecific proliferative properties, and discovery of a novel neuronal form with unique properties. Recently, a plethora of studies have implicated IL-16 in exacerbation of infectious, immune-mediated, and autoimmune inflammatory disorders, including atopic dermatitis, irritable bowel syndrome, systemic lupus erythematosus, neurodegenerative disorders, and viral infections. Herein, we review the body of evidence supporting a role for IL-16 in infectious and immune-mediated inflammatory disorders and explore the known and possible mechanism of actions in the numerous diseases.
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Easton AJ, Domachowske JB, Rosenberg HF. Animal pneumoviruses: molecular genetics and pathogenesis. Clin Microbiol Rev 2004; 17:390-412. [PMID: 15084507 PMCID: PMC387412 DOI: 10.1128/cmr.17.2.390-412.2004] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pneumoviruses are single-stranded, negative-sense, nonsegmented RNA viruses of the family Paramyxoviridae, subfamily Pneumovirinae, and include pathogens that infect humans (respiratory syncytial virus and human metapneumovirus), domestic mammals (bovine, ovine, and caprine respiratory syncytial viruses), rodents (pneumonia virus of mice), and birds (avian metapneumovirus). Among the topics considered in this review are recent studies focused on the roles of the individual virus-encoded components in promoting virus replication as well as in altering and evading innate antiviral host defenses. Advances in the molecular technology of pneumoviruses and the emergence of recombinant pneumoviruses that are leading to improved virus-based vaccine formulations are also discussed. Since pneumovirus infection in natural hosts is associated with a profound inflammatory response that persists despite adequate antiviral therapy, we also review the recent experimental treatment strategies that have focused on combined antiviral, anti-inflammatory, and immunomodulatory approaches.
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Kato M, Kimura H. Respiratory syncytial virus induces inflammation in bronchial asthma: Role of eosinophils. Allergol Int 2004. [DOI: 10.1111/j.1440-1592.2004.00352.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Soukup JM, Becker S. Role of monocytes and eosinophils in human respiratory syncytial virus infection in vitro. Clin Immunol 2003; 107:178-85. [PMID: 12804531 DOI: 10.1016/s1521-6616(03)00038-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
RSV infection in airway epithelial cells (EC) results in production of the chemokines RANTES and MIP1alpha and the leukocyte differentiation factor GM-CSF. The chemokines attract monocytes and eosinophils to the site of infection, where GM-CSF may influence their function and differentiation. In turn, these inflammatory cells may limit the progression of RSV infection, as well as initiate immune responses. In the present study, the effect of monocytes and eosinophils on viral replication and infection-dependent release of EC-derived cytokines was investigated. The modulation of immune cell costimulatory molecules, CD80, CD86, CD40, and HLA-DR, and the release of the CD4(+) T cell chemoattractant IL-16 were also investigated. Employing immunofluorescence techniques, monocytes and eosinophils in cocultures with infected EC were found to inhibit the spread of RSV to uninfected cells. Monocytes also had a significant effect on replication of RSV. Monocytes phagocytized the virus, while eosinophils inhibited reinfection mainly by extracellular means. The release of G-CSF and GM-CSF in the infected cultures was not significantly affected by either monocytes or eosinophils, while RANTES release was significantly decreased. The expression of CD40, CD80, CD86, and HLA-DR on monocytes, but not on eosinophils, increased in an RSV-dose-dependent manner. IL-16 release was not induced in RSV-infected EC, but was significantly increased in coculture with monocytes. These results suggest that both monocytes and eosinophils attracted to the site of RSV infection play an important role in confining infection, while RSV-exposed monocytes may be involved in promoting/polarizing immune responses to RSV.
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Affiliation(s)
- Joleen M Soukup
- U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC 27711, USA
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Chung HL, Kim SG. RANTES may be predictive of later recurrent wheezing after respiratory syncytial virus bronchiolitis in infants. Ann Allergy Asthma Immunol 2002; 88:463-7. [PMID: 12027066 DOI: 10.1016/s1081-1206(10)62383-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND In vitro studies have shown that RANTES is strongly induced by respiratory syncytial virus (RSV) infection in cultures of upper airway epithelial cells. RANTES is known as a chemoattractant and activator for eosinophils. OBJECTIVES We performed this study to investigate whether RANTES is increased in the airway during naturally acquired RSV bronchiolitis. RANTES levels were then evaluated in relation to the severity of illness and later development of recurrent wheezing. METHODS We measured RANTES in nasal secretions of 30 patients with acute RSV bronchiolitis. Eosinophil cationic protein (ECP) was determined to evaluate the activation of eosinophils. The severity of illness was determined by the initial PaO2 values and the duration of wheezing. At a 1-year followup, all infants were re-evaluated if they had experienced subsequent wheezing, and we investigated if RANTES levels could predict the later development of recurrent wheezing. RESULTS Both RANTES and ECP in RSV bronchiolitis were significantly higher than in controls. There was a significant correlation between the levels of RANTES and ECP. RANTES was not significantly higher in patients with severe symptoms than in patients with mild symptoms. RANTES in infants who had experienced subsequent wheezing was significantly higher than in infants who had not. CONCLUSIONS Our results showed that RANTES is increased in nasal secretion during acute RSV bronchiolitis and suggest that high levels of RANTES may be predictive of later development of recurrent wheezing.
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Affiliation(s)
- Hai Lee Chung
- Department of Pediatrics, School of Medicine, Catholic University of Taegu, Korea.
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Affiliation(s)
- J E Crowe
- Department of Pediatrics, Vanderbilt University Medical School, Nashville, TN 37232-2581, USA
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Garofalo RP, Haeberle H. Epithelial regulation of innate immunity to respiratory syncytial virus. Am J Respir Cell Mol Biol 2000; 23:581-5. [PMID: 11062135 DOI: 10.1165/ajrcmb.23.5.f204] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- R P Garofalo
- Departments of Pediatrics, and Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas 77555-0369, USA.
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22
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Karawajczyk M, Sevéus L, Garcia R, Björnsson E, Peterson CG, Roomans GM, Venge P. Piecemeal degranulation of peripheral blood eosinophils: a study of allergic subjects during and out of the pollen season. Am J Respir Cell Mol Biol 2000; 23:521-9. [PMID: 11017918 DOI: 10.1165/ajrcmb.23.4.4025] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The variability of serum and plasma levels of eosinophil granule proteins in different clinical conditions, interpreted as the result of different patterns of cytokine priming, suggests a selective mobilization of granule proteins. Inasmuch as piecemeal degranulation (PM) is the mechanism proposed for the differential release of eosinophil granule proteins, we decided to investigate whether blood eosinophils from allergic subjects show characteristics of PM during natural allergen challenge. Eosinophils from three birch-sensitive subjects were studied before and during the pollen season. Electron microscopy analysis showed that during the season, eosinophils presented morphologic features of PM. By immunogold labeling, eosinophil cationic protein (ECP) was detected not only in normal specific granules but also in the cytoplasm, in the vicinity of partially lucent specific granules. These results were confirmed by subcellular fractionation, where the amount of ECP associated with compartments containing small vesicles increased 2-fold during the pollen season. A study of the distribution of ECP, eosinophil peroxidase, and hexosaminidase in eosinophils of different densities showed that the profile of each of these proteins differed depending on cell density. All of these proteins decreased in the specific granule of hypodense cells and increased in other cell compartments. We conclude that allergen exposure causes PM of the peripheral blood eosinophils of allergic subjects, and that the density of these cells reflects the degree of degranulation. Our results provide novel information for the understanding of the selective mobilization of granule proteins into the circulation.
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Affiliation(s)
- M Karawajczyk
- Department of Medical Sciences, Clinical Chemistry, University of Uppsala, Sweden.
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23
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Ogra PL. From chimpanzee coryza to palivizumab: changing times for respiratory syncytial virus. Pediatr Infect Dis J 2000; 19:774-9; discussion 811-3. [PMID: 10959757 DOI: 10.1097/00006454-200008000-00029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- P L Ogra
- Department of Pediatrics, State University of New York at Buffalo, School of Medicine and Biomedical Sciences and Children's Hospital of Buffalo, USA.
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Erjefält JS, Persson CG. New aspects of degranulation and fates of airway mucosal eosinophils. Am J Respir Crit Care Med 2000; 161:2074-85. [PMID: 10852790 DOI: 10.1164/ajrccm.161.6.9906085] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- J S Erjefält
- Department of Physiological Sciences, Lund University Hospital, Lund, Sweden
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Domachowske JB, Rosenberg HF. Respiratory syncytial virus infection: immune response, immunopathogenesis, and treatment. Clin Microbiol Rev 1999; 12:298-309. [PMID: 10194461 PMCID: PMC88919 DOI: 10.1128/cmr.12.2.298] [Citation(s) in RCA: 160] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Respiratory syncytial virus (RSV) is the single most important cause of lower respiratory tract infection during infancy and early childhood. Once RSV infection is established, the host immune response includes the production of virus-neutralizing antibodies and T-cell-specific immunity. The humoral immune response normally results in the development of anti-RSV neutralizing-antibody titers, but these are often suboptimal during an infant's initial infection. Even when the production of RSV neutralizing antibody following RSV infection is robust, humoral immunity wanes over time. Reinfection during subsequent seasons is common. The cellular immune response to RSV infection is also important for the clearance of virus. This immune response, vital for host defense against RSV, is also implicated in the immunopathogenesis of severe lower respiratory tract RSV bronchiolitis. Many details of the immunology and immunopathologic mechanisms of RSV disease known at present have been learned from rodent models of RSV disease and are discussed in some detail. In addition, the roles of immunoglobulin E, histamine, and eosinophils in the immunopathogenesis of RSV disease are considered. Although the treatment of RSV bronchiolitis is primarily supportive, the role of ribavirin is briefly discussed. Novel approaches to the development of new antiviral drugs with promising anti-RSV activity in vitro are also described.
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Affiliation(s)
- J B Domachowske
- State University of New York Health Science Center at Syracuse, Syracuse, New York 13210,
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Domachowske JB, Bonville CA, Dyer KD, Rosenberg HF. Evolution of antiviral activity in the ribonuclease A gene superfamily: evidence for a specific interaction between eosinophil-derived neurotoxin (EDN/RNase 2) and respiratory syncytial virus. Nucleic Acids Res 1998; 26:5327-32. [PMID: 9826755 PMCID: PMC147995 DOI: 10.1093/nar/26.23.5327] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have demonstrated that the human eosinophil-derived neurotoxin (EDN, RNase 2), a rapidly evolving secretory protein derived from eosinophilic leukocytes, mediates the ribonucleolytic destruction of extracellular virions of the single-stranded RNA virus respiratory syncytial virus (RSV). While RNase activity is crucial to antiviral activity, it is clearly not sufficient, as our results suggest that EDN has unique structural features apart from RNase activity that are necessary to promote antiviral activity. We demonstrate here that the interaction between EDN and extracellular virions of RSV is both saturatable and specific. Increasing concentrations of the antivirally inactivated, ribonucleolytically inactivated point mutant form of recombinant human EDN, rhEDNdK38, inhibits rhEDN's antiviral activity, while increasing concentrations of the related RNase, recombinant human RNase k6, have no effect whatsoever. Interestingly, acquisition of antiviral activity parallels the evolutionary development of the primate EDN lineage, having emerged some time after the divergence of the Old World from the New World monkeys. Using this information, we created ribonucleolytically active chimeras of human and New World monkey orthologs of EDN and, by evaluating their antiviral activity, we have identified an N-terminal segment of human EDN that contains one or more of the sequence elements that mediate its specific interaction with RSV.
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Affiliation(s)
- J B Domachowske
- Department of Pediatrics, Division of Infectious Diseases, State University of New York Health Science Center at Syracuse, Syracuse, NY 13210, USA
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27
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Domachowske JB, Dyer KD, Adams AG, Leto TL, Rosenberg HF. Eosinophil cationic protein/RNase 3 is another RNase A-family ribonuclease with direct antiviral activity. Nucleic Acids Res 1998; 26:3358-63. [PMID: 9649619 PMCID: PMC147714 DOI: 10.1093/nar/26.14.3358] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Eosinophil cationic protein (ECP) is one of two RNase A-superfamily ribonucleases found in secretory granules of human eosinophilic leukocytes. Although the physiologic function of eosinophils [and thus of the two eosinophil ribonucleases, ECP and eosinophil-derived neurotoxin (EDN)] remains controversial, we have recently shown that isolated human eosinophils promote ribonuclease-dependent toxicity toward extracellular virions of the single-stranded RNA virus, respiratory syncytial virus, group B (RSV-B). We have also shown that recombinant human EDN (rhEDN) can act alone as a ribonuclease-dependent antiviral agent. In this work, we provide a biochemical characterization of recombinant human ECP (rhECP) prepared in baculovirus, and demonstrate that rhECP also promotes ribonuclease-dependent antiviral activity. The rhECP described here is N-glycosylated, as is native ECP, and has approximately 100-fold more ribonuclease activity than non-glycosylated rhECP prepared in bacteria. The enzymatic activity of rhECP was sensitive to inhibition by placental ribonuclease inhibitor (RI). Although rhECP was not as effective as rhEDN at reducing viral infectivity (500 nM rhECP reduced infectivity of RSV-B approximately 6 fold; 500 nM rhEDN, >50 fold), the antiviral activity appears to be unique to the eosinophil ribonucleases; no reduction in infectivity was promoted by bovine RNase A, by the amphibian ribonuclease, onconase, nor by the closely-related human ribonuclease, RNase k6. Interestingly, combinations of rhEDN and rhECP did not result in either a synergistic or even an additive antiviral effect. Taken together, these results suggest that that the interaction between the eosinophil ribonucleases and the extracellular virions of RSV-B may be specific and saturable.
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Affiliation(s)
- J B Domachowske
- Department of Pediatrics, State University of New York Health Science Center at Syracuse, Syracuse, NY 13210, USA
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Olszewska-Pazdrak B, Casola A, Saito T, Alam R, Crowe SE, Mei F, Ogra PL, Garofalo RP. Cell-specific expression of RANTES, MCP-1, and MIP-1alpha by lower airway epithelial cells and eosinophils infected with respiratory syncytial virus. J Virol 1998; 72:4756-64. [PMID: 9573240 PMCID: PMC110009 DOI: 10.1128/jvi.72.6.4756-4764.1998] [Citation(s) in RCA: 209] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Respiratory syncytial virus (RSV) is the major cause of acute bronchiolitis in infancy, a syndrome characterized by wheezing, respiratory distress, and the pathologic findings of peribronchial mononuclear cell infiltration and release of inflammatory mediators by basophil and eosinophil leukocytes. Composition and activation of this cellular response are thought to rely on the discrete target cell selectivity of C-C chemokines. We demonstrate that infection in vitro of human epithelial cells of the lower respiratory tract by RSV induced dose- and time-dependent increases in mRNA and protein secretion for RANTES (regulated upon activation, normal T-cell expressed and presumably secreted), monocyte chemotactic protein-1 (MCP-1), and macrophage inflammatory protein-1alpha (MIP-1alpha). Production of MCP-1 and MIP-1alpha was selectively localized only in epithelial cells of the small airways and lung. Exposure of epithelial cells to gamma interferon (IFN-gamma), in combination with RSV infection, induced a significant increase in RANTES production that was synergistic with respect to that obtained by RSV infection or IFN-gamma treatment alone. Epithelial cell-derived chemokines exhibited a strong chemotactic activity for normal human blood eosinophils. Furthermore, eosinophils were susceptible to RSV and released RANTES and MIP-1alpha as a result of infection. Therefore, the inflammatory process in RSV-induced bronchiolitis appears to be triggered by the infection of epithelial cells and further amplified via mechanisms driven by IFN-gamma and by the secretion of eosinophil chemokines.
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Affiliation(s)
- B Olszewska-Pazdrak
- Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas 77555-0369, USA
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