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Evidence against the Human Metapneumovirus G, SH, and M2-2 Proteins as Bona Fide Interferon Antagonists. J Virol 2022; 96:e0072322. [PMID: 35975999 PMCID: PMC9472654 DOI: 10.1128/jvi.00723-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The production of type I interferon (IFN) is the hallmark of the innate immune response. Most, if not all, mammalian viruses have a way to circumvent this response. Fundamental knowledge on viral evasion of innate immune responses may facilitate the design of novel antiviral therapies. To investigate how human metapneumovirus (HMPV) interacts with the innate immune response, recombinant viruses lacking G, short hydrophobic (SH), or M2-2 protein expression were assessed for IFN induction in A549 cells. HMPV lacking G or SH protein expression induced similarly low levels of IFN, compared to the wild-type virus, whereas HMPV lacking M2-2 expression induced significantly more IFN than the wild-type virus. However, sequence analysis of the genomes of M2-2 mutant viruses revealed large numbers of mutations throughout the genome. Over 70% of these nucleotide substitutions were A-to-G and T-to-C mutations, consistent with the properties of the adenosine deaminase acting on RNA (ADAR) protein family. Knockdown of ADAR1 by CRISPR interference confirmed the role of ADAR1 in the editing of M2-2 deletion mutant virus genomes. More importantly, Northern blot analyses revealed the presence of defective interfering RNAs (DIs) in M2-2 mutant viruses and not in the wild-type virus or G and SH deletion mutant viruses. DIs are known to be potent inducers of the IFN response. The presence of DIs in M2-2 mutant virus stocks and hypermutated virus genomes interfere with studies on HMPV and the innate immune response and should be addressed in future studies. IMPORTANCE Understanding the interaction between viruses and the innate immune response is one of the barriers to the design of antiviral therapies. Here, we investigated the role of the G, SH, and M2-2 proteins of HMPV as type I IFN antagonists. In contrast to other studies, no IFN-antagonistic functions could be observed for the G and SH proteins. HMPV with a deletion of the M2-2 protein did induce type I IFN production upon infection of airway epithelial cells. However, during generation of virus stocks, these viruses rapidly accumulated DIs, which are strong activators of the type I IFN response. Additionally, the genomes of these viruses were hypermutated, which was prevented by generating stocks in ADAR knockdown cells, confirming a role for ADAR in hypermutation of HMPV genomes or DIs. These data indicate that a role of the HMPV M2-2 protein as a bona fide IFN antagonist remains elusive.
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Zoonotic Origins of Human Metapneumovirus: A Journey from Birds to Humans. Viruses 2022; 14:v14040677. [PMID: 35458407 PMCID: PMC9028271 DOI: 10.3390/v14040677] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/23/2022] [Accepted: 03/23/2022] [Indexed: 01/13/2023] Open
Abstract
Metapneumoviruses, members of the family Pneumoviridae, have been identified in birds (avian metapneumoviruses; AMPV’s) and humans (human metapneumoviruses; HMPV’s). AMPV and HMPV are closely related viruses with a similar genomic organization and cause respiratory tract illnesses in birds and humans, respectively. AMPV can be classified into four subgroups, A–D, and is the etiological agent of turkey rhinotracheitis and swollen head syndrome in chickens. Epidemiological studies have indicated that AMPV also circulates in wild bird species which may act as reservoir hosts for novel subtypes. HMPV was first discovered in 2001, but retrospective studies have shown that HMPV has been circulating in humans for at least 50 years. AMPV subgroup C is more closely related to HMPV than to any other AMPV subgroup, suggesting that HMPV has evolved from AMPV-C following zoonotic transfer. In this review, we present a historical perspective on the discovery of metapneumoviruses and discuss the host tropism, pathogenicity, and molecular characteristics of the different AMPV and HMPV subgroups to provide increased focus on the necessity to better understand the evolutionary pathways through which HMPV emerged as a seasonal endemic human respiratory virus.
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Host Components That Modulate the Disease Caused by hMPV. Viruses 2021; 13:v13030519. [PMID: 33809875 PMCID: PMC8004172 DOI: 10.3390/v13030519] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/27/2021] [Accepted: 03/01/2021] [Indexed: 12/13/2022] Open
Abstract
Human metapneumovirus (hMPV) is one of the main pathogens responsible for acute respiratory infections in children up to 5 years of age, contributing substantially to health burden. The worldwide economic and social impact of this virus is significant and must be addressed. The structural components of hMPV (either proteins or genetic material) can be detected by several receptors expressed by host cells through the engagement of pattern recognition receptors. The recognition of the structural components of hMPV can promote the signaling of the immune response to clear the infection, leading to the activation of several pathways, such as those related to the interferon response. Even so, several intrinsic factors are capable of modulating the immune response or directly inhibiting the replication of hMPV. This article will discuss the current knowledge regarding the innate and adaptive immune response during hMPV infections. Accordingly, the host intrinsic components capable of modulating the immune response and the elements capable of restricting viral replication during hMPV infections will be examined.
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Rogers MC, Miranda-Katz M, Zhang Y, Oury TD, Uccellini MB, García-Sastre A, Williams JV. STAT2 Limits Host Species Specificity of Human Metapneumovirus. Viruses 2020; 12:E724. [PMID: 32635475 PMCID: PMC7412095 DOI: 10.3390/v12070724] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/01/2020] [Accepted: 07/02/2020] [Indexed: 12/24/2022] Open
Abstract
The host tropism of viral infection is determined by a variety of factors, from cell surface receptors to innate immune signaling. Many viruses encode proteins that interfere with host innate immune recognition in order to promote infection. STAT2 is divergent between species and therefore has a role in species restriction of some viruses. To understand the role of STAT2 in human metapneumovirus (HMPV) infection of human and murine tissues, we first infected STAT2-/- mice and found that HMPV could be serially passaged in STAT2-/-, but not WT, mice. We then used in vitro methods to show that HMPV inhibits expression of both STAT1 and STAT2 in human and primate cells, but not in mouse cells. Transfection of the murine form of STAT2 into STAT2-deficient human cells conferred resistance to STAT2 inhibition. Finally, we sought to understand the in vivo role of STAT2 by infecting hSTAT2 knock-in mice with HMPV, and found that mice had increased weight loss, inhibition of type I interferon signaling, and a Th2-polarized cytokine profile compared to WT mice. These results indicate that STAT2 is a target of HMPV in human infection, while the murine version of STAT2 restricts tropism of HMPV for murine cells and tissue.
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Affiliation(s)
- Meredith C. Rogers
- Department of Pediatrics, University of Pittsburgh School of Medicine and UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224, USA; (M.C.R.); (M.M.-K.); (Y.Z.)
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Margot Miranda-Katz
- Department of Pediatrics, University of Pittsburgh School of Medicine and UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224, USA; (M.C.R.); (M.M.-K.); (Y.Z.)
| | - Yu Zhang
- Department of Pediatrics, University of Pittsburgh School of Medicine and UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224, USA; (M.C.R.); (M.M.-K.); (Y.Z.)
| | - Tim D. Oury
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA;
| | - Melissa B. Uccellini
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; (M.B.U.); (A.G.-S.)
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; (M.B.U.); (A.G.-S.)
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Medicine, Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - John V. Williams
- Department of Pediatrics, University of Pittsburgh School of Medicine and UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224, USA; (M.C.R.); (M.M.-K.); (Y.Z.)
- Institute for Infection, Inflammation, and Immunity in Children (i4Kids), University of Pittsburgh, Pittsburgh, PA 15224, USA
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Prospects of and Barriers to the Development of Epitope-Based Vaccines against Human Metapneumovirus. Pathogens 2020; 9:pathogens9060481. [PMID: 32570728 PMCID: PMC7350342 DOI: 10.3390/pathogens9060481] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/10/2020] [Accepted: 06/16/2020] [Indexed: 12/21/2022] Open
Abstract
Human metapneumovirus (HMPV) is a major cause of respiratory illnesses in children, the elderly and immunocompromised patients. Although this pathogen was only discovered in 2001, an enormous amount of research has been conducted in order to develop safe and effective vaccines to prevent people from contracting the disease. In this review, we summarize current knowledge about the most promising experimental B- and T-cell epitopes of human metapneumovirus for the rational design of HMPV vaccines using vector delivery systems, paying special attention to the conservation of these epitopes among different lineages/genotypes of HMPV. The prospects of the successful development of an epitope-based HMPV vaccine are discussed in the context of recent findings regarding HMPV’s ability to modulate host immunity. In particular, we discuss the lack of data on experimental human CD4 T-cell epitopes for HMPV despite the role of CD4 lymphocytes in both the induction of higher neutralizing antibody titers and the establishment of CD8 memory T-cell responses. We conclude that current research should be focused on searching for human CD4 T-cell epitopes of HMPV that can help us to design a safe and cross-protective epitope-based HMPV vaccine.
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Andrade CA, Pacheco GA, Gálvez NMS, Soto JA, Bueno SM, Kalergis AM. Innate Immune Components that Regulate the Pathogenesis and Resolution of hRSV and hMPV Infections. Viruses 2020; 12:E637. [PMID: 32545470 PMCID: PMC7354512 DOI: 10.3390/v12060637] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/09/2020] [Accepted: 06/09/2020] [Indexed: 02/06/2023] Open
Abstract
The human respiratory syncytial virus (hRSV) and human Metapneumovirus (hMPV) are two of the leading etiological agents of acute lower respiratory tract infections, which constitute the main cause of mortality in infants. However, there are currently approved vaccines for neither hRSV nor hMPV. Moreover, despite the similarity between the pathology caused by both viruses, the immune response elicited by the host is different in each case. In this review, we discuss how dendritic cells, alveolar macrophages, neutrophils, eosinophils, natural killer cells, innate lymphoid cells, and the complement system regulate both pathogenesis and the resolution of hRSV and hMPV infections. The roles that these cells play during infections by either of these viruses will help us to better understand the illnesses they cause. We also discuss several controversial findings, relative to some of these innate immune components. To better understand the inflammation in the lungs, the role of the respiratory epithelium in the recruitment of innate immune cells is briefly discussed. Finally, we review the main prophylactic strategies and current vaccine candidates against both hRSV and hMPV.
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Affiliation(s)
- Catalina A. Andrade
- Millennium Institute of Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8320000, Chile; (C.A.A.); (G.A.P.); (N.M.S.G.); (J.A.S.); (S.M.B.)
| | - Gaspar A. Pacheco
- Millennium Institute of Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8320000, Chile; (C.A.A.); (G.A.P.); (N.M.S.G.); (J.A.S.); (S.M.B.)
| | - Nicolas M. S. Gálvez
- Millennium Institute of Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8320000, Chile; (C.A.A.); (G.A.P.); (N.M.S.G.); (J.A.S.); (S.M.B.)
| | - Jorge A. Soto
- Millennium Institute of Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8320000, Chile; (C.A.A.); (G.A.P.); (N.M.S.G.); (J.A.S.); (S.M.B.)
| | - Susan M. Bueno
- Millennium Institute of Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8320000, Chile; (C.A.A.); (G.A.P.); (N.M.S.G.); (J.A.S.); (S.M.B.)
| | - Alexis M. Kalergis
- Millennium Institute of Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8320000, Chile; (C.A.A.); (G.A.P.); (N.M.S.G.); (J.A.S.); (S.M.B.)
- Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8320000, Chile
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Ballegeer M, Saelens X. Cell-Mediated Responses to Human Metapneumovirus Infection. Viruses 2020; 12:v12050542. [PMID: 32423043 PMCID: PMC7290942 DOI: 10.3390/v12050542] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 05/09/2020] [Accepted: 05/12/2020] [Indexed: 12/29/2022] Open
Abstract
Viruses are the most common cause of acute respiratory tract infections (ARTI). Human metapneumovirus (hMPV) frequently causes viral pneumonia which can become life-threatening if the virus spreads to the lungs. Even though hMPV was only isolated in 2001, this negative-stranded RNA virus has probably been circulating in the human population for many decades. Interestingly, almost all adults have serologic evidence of hMPV infection. A well-established host immune response is evoked when hMPV infection occurs. However, the virus has evolved to circumvent and even exploit the host immune response. Further, infection with hMPV induces a weak memory response, and re-infections during life are common. In this review, we provide a comprehensive overview of the different cell types involved in the immune response in order to better understand the immunopathology induced by hMPV. Such knowledge may contribute to the development of vaccines and therapeutics directed against hMPV.
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Affiliation(s)
- Marlies Ballegeer
- VIB-UGent Center for Medical Biotechnology, VIB, B-9052 Ghent, Belgium;
- Department of Biochemistry and Microbiology, Ghent University, B-9000 Ghent, Belgium
| | - Xavier Saelens
- VIB-UGent Center for Medical Biotechnology, VIB, B-9052 Ghent, Belgium;
- Department of Biochemistry and Microbiology, Ghent University, B-9000 Ghent, Belgium
- Correspondence:
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Cell-Mediated Responses to Human Metapneumovirus Infection. Viruses 2020; 12:542. [PMID: 32423043 PMCID: PMC7290942 DOI: 10.3390/v12050542&set/a 882111696+808152660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Viruses are the most common cause of acute respiratory tract infections (ARTI). Human metapneumovirus (hMPV) frequently causes viral pneumonia which can become life-threatening if the virus spreads to the lungs. Even though hMPV was only isolated in 2001, this negative-stranded RNA virus has probably been circulating in the human population for many decades. Interestingly, almost all adults have serologic evidence of hMPV infection. A well-established host immune response is evoked when hMPV infection occurs. However, the virus has evolved to circumvent and even exploit the host immune response. Further, infection with hMPV induces a weak memory response, and re-infections during life are common. In this review, we provide a comprehensive overview of the different cell types involved in the immune response in order to better understand the immunopathology induced by hMPV. Such knowledge may contribute to the development of vaccines and therapeutics directed against hMPV.
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9
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Cell-Mediated Responses to Human Metapneumovirus Infection. Viruses 2020. [DOI: 10.3390/v12050542
expr 836379838 + 819716165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Viruses are the most common cause of acute respiratory tract infections (ARTI). Human metapneumovirus (hMPV) frequently causes viral pneumonia which can become life-threatening if the virus spreads to the lungs. Even though hMPV was only isolated in 2001, this negative-stranded RNA virus has probably been circulating in the human population for many decades. Interestingly, almost all adults have serologic evidence of hMPV infection. A well-established host immune response is evoked when hMPV infection occurs. However, the virus has evolved to circumvent and even exploit the host immune response. Further, infection with hMPV induces a weak memory response, and re-infections during life are common. In this review, we provide a comprehensive overview of the different cell types involved in the immune response in order to better understand the immunopathology induced by hMPV. Such knowledge may contribute to the development of vaccines and therapeutics directed against hMPV.
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10
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Human metapneumovirus activates NOD-like receptor protein 3 inflammasome via its small hydrophobic protein which plays a detrimental role during infection in mice. PLoS Pathog 2019; 15:e1007689. [PMID: 30964929 PMCID: PMC6474638 DOI: 10.1371/journal.ppat.1007689] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 04/19/2019] [Accepted: 03/08/2019] [Indexed: 12/30/2022] Open
Abstract
NOD-like receptor protein 3 (NLRP3) inflammasome activation triggers caspase-1 activation-induced maturation of interleukin (IL)-1β and IL-18 and therefore is important for the development of the host defense against various RNA viral diseases. However, the implication of this protein complex in human metapneumovirus (HMPV) disease has not been fully studied. Herein, we report that NLRP3 inflammasome plays a detrimental role during HMPV infection because NLRP3 inflammasome inhibition protected mice from mortality and reduced weight loss and inflammation without impacting viral replication. We also demonstrate that NLRP3 inflammasome exerts its deleterious effect via IL-1β production since we observed reduced mortality, weight loss and inflammation in IL-1β-deficient (IL-1β-/-) mice, as compared to wild-type animals during HMPV infection. Moreover, the effect on these evaluated parameters was not different in IL-1β-/- and wild-type mice treated with an NLRP3 inflammasome inhibitor. The production of IL-1β was also abrogated in bone marrow derived macrophages deficient for NLRP3. Finally, we show that small hydrophobic protein-deleted recombinant HMPV (HMPV ΔSH) failed to activate caspase-1, which is responsible for IL-1β cleavage and maturation. Furthermore, HMPV ΔSH-infected mice had less weight loss, showed no mortality and reduced inflammation, as compared to wild-type HMPV-infected mice. Thus, NLRP3 inflammasome activation seems to be triggered by HMPV SH protein in HMPV disease. In summary, once activated by the HMPV SH protein, NLRP3 inflammasome promotes the maturation of IL-1β, which exacerbates HMPV-induced inflammation. Therefore, the blockade of IL-1β production by using NLRP3 inflammasome inhibitors might be a novel potential strategy for the therapy and prevention of HMPV infection. Human metapneumovirus (HMPV), a negative-stranded, enveloped RNA virus, is recognized as one of the leading causes of acute respiratory disease in children since its discovery in 2001. Nevertheless, there is currently no licensed vaccine for the prevention of HMPV infection and treatment modalities are limited to the use of ribavirin, a weak antiviral agent or immunoglobulins. NOD-like receptor protein 3 (NLRP3) inflammasome has been shown to be involved in the pathogenesis of several RNA viral diseases but its role during HMPV infection has not been fully studied. Here, we report for the first time that NLRP3 inflammasome is activated by the small hydrophobic protein of HMPV, leading to the release of IL-1β, which has the potential to exacerbate inflammation. However, NLRP3 inflammasome has no direct influence on viral replication. Thus, IL-1β-mediated inflammatory process plays an important role during HMPV infection and, therefore, anti-IL-1β strategies such as the use of NLRP3 inhibitors may be a novel potential approach for the prevention and therapy of HMPV disease.
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Uche IK, Guerrero-Plata A. Interferon-Mediated Response to Human Metapneumovirus Infection. Viruses 2018; 10:v10090505. [PMID: 30231515 PMCID: PMC6163993 DOI: 10.3390/v10090505] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 09/12/2018] [Accepted: 09/15/2018] [Indexed: 12/13/2022] Open
Abstract
Human metapneumovirus (HMPV) is one of the leading causes of respiratory diseases in infants and children worldwide. Although this pathogen infects mainly young children, elderly and immunocompromised people can be also seriously affected. To date, there is no commercial vaccine available against it. Upon HMPV infection, the host innate arm of defense produces interferons (IFNs), which are critical for limiting HMPV replication. In this review, we offer an updated landscape of the HMPV mediated-IFN response in different models as well as some of the defense tactics employed by the virus to circumvent IFN response.
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Affiliation(s)
- Ifeanyi K Uche
- Department of Pathobiological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
| | - Antonieta Guerrero-Plata
- Department of Pathobiological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
- Center for Experimental Infectious Disease Research, Louisiana State University, Baton Rouge, LA 70803, USA.
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