1
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Ferella A, Mozgovoj M, Garanzini D, Dus Santos MJ, Calamante G, Del Médico Zajac MP. The MVA vector expressing the F protein of bovine respiratory syncytial virus is immunogenic in systemic and mucosal immunization routes. Rev Argent Microbiol 2024; 56:125-133. [PMID: 38143232 DOI: 10.1016/j.ram.2023.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 06/12/2023] [Accepted: 07/27/2023] [Indexed: 12/26/2023] Open
Abstract
Bovine respiratory syncytial virus (BRSV) affects both beef and dairy cattle, reaching morbidity and mortality rates of 60-80% and 20%, respectively. The aim of this study was to obtain a recombinant MVA expressing the BRSV F protein (MVA-F) as a vaccine against BRSV and to evaluate the immune response induced by MVA-F after systemic immunization in homologous and heterologous vaccination (MVA-F alone or combined with a subunit vaccine), and after intranasal immunization of mice. MVA-F administered by intraperitoneal route in a homologous scheme elicited levels of neutralizing antibodies similar to those obtained with inactivated BRSV as well as better levels of IFN-γ secretion. In addition, nasal administration of MVA-F elicited local and systemic immunity with a Th1 profile. This study suggests that MVA-F is a good candidate for further evaluations combining intranasal and intramuscular routes, in order to induce local and systemic immune responses, to improve the vaccine efficacy against BRSV infection.
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Affiliation(s)
- Alejandra Ferella
- Instituto de Virología e Innovaciones Tecnológicas (IVIT), Instituto Nacional de Tecnología Agropecuaria (INTA), Consejo Nacional de investigaciones Científicas y Técnicas (CONICET), Nicolás Repetto y De Los Reseros S/N° (B1686IGC), Hurlingham, Buenos Aires, Argentina
| | - Marina Mozgovoj
- Instituto de Virología e Innovaciones Tecnológicas (IVIT), Instituto Nacional de Tecnología Agropecuaria (INTA), Consejo Nacional de investigaciones Científicas y Técnicas (CONICET), Nicolás Repetto y De Los Reseros S/N° (B1686IGC), Hurlingham, Buenos Aires, Argentina
| | - Débora Garanzini
- Instituto de Agrobiotecnología y Biología Molecular (IABiMo), Instituto Nacional de Tecnología Agropecuaria (INTA), Consejo Nacional de investigaciones Científicas y Técnicas (CONICET), Nicolás Repetto y De Los Reseros S/N° (B1686IGC), Hurlingham, Buenos Aires, Argentina
| | - María José Dus Santos
- Instituto de Virología e Innovaciones Tecnológicas (IVIT), Instituto Nacional de Tecnología Agropecuaria (INTA), Consejo Nacional de investigaciones Científicas y Técnicas (CONICET), Nicolás Repetto y De Los Reseros S/N° (B1686IGC), Hurlingham, Buenos Aires, Argentina
| | - Gabriela Calamante
- Instituto de Agrobiotecnología y Biología Molecular (IABiMo), Instituto Nacional de Tecnología Agropecuaria (INTA), Consejo Nacional de investigaciones Científicas y Técnicas (CONICET), Nicolás Repetto y De Los Reseros S/N° (B1686IGC), Hurlingham, Buenos Aires, Argentina
| | - María Paula Del Médico Zajac
- Instituto de Agrobiotecnología y Biología Molecular (IABiMo), Instituto Nacional de Tecnología Agropecuaria (INTA), Consejo Nacional de investigaciones Científicas y Técnicas (CONICET), Nicolás Repetto y De Los Reseros S/N° (B1686IGC), Hurlingham, Buenos Aires, Argentina.
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2
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Cavallazzi R, Ramirez JA. Influenza and Viral Pneumonia. Infect Dis Clin North Am 2024; 38:183-212. [PMID: 38280763 DOI: 10.1016/j.idc.2023.12.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2024]
Abstract
Influenza and other respiratory viruses are commonly identified in patients with community-acquired pneumonia, hospital-acquired pneumonia, and in immunocompromised patients with pneumonia. Clinically, it is difficult to differentiate viral from bacterial pneumonia. Similarly, the radiological findings of viral infection are in general nonspecific. The advent of polymerase chain reaction testing has enormously facilitated the identification of respiratory viruses, which has important implications for infection control measures and treatment. Currently, treatment options for patients with viral infection are limited but there is ongoing research on the development and clinical testing of new treatment regimens and strategies.
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Affiliation(s)
- Rodrigo Cavallazzi
- Division of Pulmonary, Critical Care, and Sleep Disorders, University of Louisville, Louisville, KY, USA.
| | - Julio A Ramirez
- Norton Infectious Diseases Institute, Norton Healthcare, Louisville, KY, USA
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3
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Ballegeer M, van Scherpenzeel RC, Delgado T, Iglesias-Caballero M, García Barreno B, Pandey S, Rush SA, Kolkman JA, Mas V, McLellan JS, Saelens X. A neutralizing single-domain antibody that targets the trimer interface of the human metapneumovirus fusion protein. mBio 2024; 15:e0212223. [PMID: 38117059 PMCID: PMC10790764 DOI: 10.1128/mbio.02122-23] [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: 08/22/2023] [Accepted: 11/14/2023] [Indexed: 12/21/2023] Open
Abstract
IMPORTANCE Human metapneumovirus (hMPV) is an important respiratory pathogen for which no licensed antivirals or vaccines exist. Single-domain antibodies represent promising antiviral biologics that can be easily produced and formatted. We describe the isolation and detailed characterization of two hMPV-neutralizing single-domain antibodies that are directed against the fusion protein F. One of these single-domain antibodies broadly neutralizes hMPV A and B strains, can prevent proteolytic maturation of F, and binds to an epitope in the F trimer interface. This suggests that hMPV pre-F undergoes trimer opening or "breathing" on infectious virions, exposing a vulnerable site for neutralizing antibodies. Finally, we show that this single-domain antibody, fused to a human IgG1 Fc, can protect cotton rats against hMPV replication, an important finding for potential future clinical applications.
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Affiliation(s)
- Marlies Ballegeer
- VIB Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | | | - Teresa Delgado
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
| | | | | | - Shubham Pandey
- VIB Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Scott A. Rush
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
| | | | - Vicente Mas
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
| | - Jason S. McLellan
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
| | - Xavier Saelens
- VIB Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
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4
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Xiao X, Wen Z, Chen Q, Shipman JM, Kostas J, Reid JC, Warren C, Tang A, Luo B, O’Donnell G, Fridman A, Chen Z, Vora KA, Zhang L, Su HP, Eddins MJ. Structural characterization of M8C10, a neutralizing antibody targeting a highly conserved prefusion-specific epitope on the metapneumovirus fusion trimerization interface. J Virol 2023; 97:e0105223. [PMID: 38032197 PMCID: PMC10734504 DOI: 10.1128/jvi.01052-23] [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: 07/17/2023] [Accepted: 10/23/2023] [Indexed: 12/01/2023] Open
Abstract
IMPORTANCE Human metapneumovirus (hMPV) is a common pathogen causing lower respiratory tract infections worldwide and can develop severe symptoms in high-risk populations such as infants, the elderly, and immunocompromised patients. There are no approved hMPV vaccines or neutralizing antibodies available for therapeutic or prophylactic use. The trimeric hMPV fusion F protein is the major target of neutralizing antibodies in human sera. Understanding the immune recognition of antibodies to hMPV-F antigen will provide critical insights into developing efficacious hMPV monoclonal antibodies and vaccines.
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Affiliation(s)
- Xiao Xiao
- Infectious Diseases and Vaccines Discovery, Merck & Co., Inc., West Point, Pennsylvania, USA
- Discovery Biologics, Merck & Co., Inc., Boston, Massachusetts, USA
- MRL Postdoctoral Research Program, Merck & Co., Inc., Kenilworth, New Jersey, USA
| | - Zhiyun Wen
- Infectious Diseases and Vaccines Discovery, Merck & Co., Inc., West Point, Pennsylvania, USA
| | - Qing Chen
- Protein and Structural Chemistry, Merck & Co., Inc., West Point, Pennsylvania, USA
| | - Jennifer M. Shipman
- Protein and Structural Chemistry, Merck & Co., Inc., West Point, Pennsylvania, USA
| | - James Kostas
- Protein and Structural Chemistry, Merck & Co., Inc., West Point, Pennsylvania, USA
| | - John C. Reid
- Protein and Structural Chemistry, Merck & Co., Inc., West Point, Pennsylvania, USA
| | - Christopher Warren
- Infectious Diseases and Vaccines Discovery, Merck & Co., Inc., West Point, Pennsylvania, USA
| | - Aimin Tang
- Infectious Diseases and Vaccines Discovery, Merck & Co., Inc., West Point, Pennsylvania, USA
| | - Bin Luo
- Quantitative Biosciences, Merck & Co., Inc., West Point, Pennsylvania, USA
| | - Gregory O’Donnell
- Quantitative Biosciences, Merck & Co., Inc., West Point, Pennsylvania, USA
| | - Arthur Fridman
- Data Science and Scientific Informatics, Merck & Co., Inc., Rahway, New Jersey, USA
| | - Zhifeng Chen
- Infectious Diseases and Vaccines Discovery, Merck & Co., Inc., West Point, Pennsylvania, USA
| | - Kalpit A. Vora
- Infectious Diseases and Vaccines Discovery, Merck & Co., Inc., West Point, Pennsylvania, USA
| | - Lan Zhang
- Infectious Diseases and Vaccines Discovery, Merck & Co., Inc., West Point, Pennsylvania, USA
| | - Hua-Poo Su
- Protein and Structural Chemistry, Merck & Co., Inc., West Point, Pennsylvania, USA
| | - Michael J. Eddins
- Protein and Structural Chemistry, Merck & Co., Inc., West Point, Pennsylvania, USA
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5
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Meza UC, Lara NP, Gómez LC, Rodríguez MS, Hernández JRA, Mendoza RT. The HRA2pl fusion peptide exerts in vitro antiviral activity against human respiratory paramyxoviruses and pneumoviruses. Front Cell Infect Microbiol 2023; 13:1125135. [PMID: 37153148 PMCID: PMC10157160 DOI: 10.3389/fcimb.2023.1125135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 03/29/2023] [Indexed: 05/09/2023] Open
Abstract
Acute respiratory infections are a group of diseases caused by viruses, bacteria, and parasites that mainly affect children until the age of 5 and immunocompromised senior adults. In Mexico, these infections are the main cause of morbidity in children, with more than 26 million cases of respiratory infections reported by the Secretariat of Health, in 2019. The human respiratory syncytial virus (hRSV), the human metapneumovirus (hMPV), and the human parainfluenza-2 (hPIV-2) are responsible for many respiratory infections. Currently, palivizumab, a monoclonal antibody against the fusion protein F, is the treatment of choice against hRSV infections. This protein is being studied for the design of antiviral peptides that act by inhibiting the fusion of the virus and the host cell. Therefore, we examined the antiviral activity of the HRA2pl peptide, which competes the heptad repeat A domain of the F protein of hMPV. The recombinant peptide was obtained using a viral transient expression system. The effect of the fusion peptide was evaluated with an in vitro entry assay. Moreover, the effectiveness of HRA2pl was examined in viral isolates from clinical samples obtained from patients with infections caused by hRSV, hMPV, or hPIV-2, by evaluating the viral titer and the syncytium size. The HRA2pl peptide affected the viruses' capacity of entry, resulting in a 4-log decrease in the viral titer compared to the untreated viral strains. Additionally, a 50% reduction in the size of the syncytium was found. These results demonstrate the antiviral potential of HRA2pl in clinical samples, paving the way toward clinical trials.
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Affiliation(s)
- Uriel Cruz Meza
- Department of Microbiology and Parasitology, Faculty of Medicine, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
| | - Norvell Perezbusta Lara
- Department of Microbiology and Parasitology, Faculty of Medicine, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
| | - Laura Chávez Gómez
- Department of Microbiology and Parasitology, Faculty of Medicine, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
| | | | - Javier R. Ambrosio Hernández
- Department of Microbiology and Parasitology, Faculty of Medicine, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
| | - Rocio Tirado Mendoza
- Department of Microbiology and Parasitology, Faculty of Medicine, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
- *Correspondence: Rocio Tirado Mendoza,
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6
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Characterization of prefusion-F-specific antibodies elicited by natural infection with human metapneumovirus. Cell Rep 2022; 40:111399. [PMID: 36130517 DOI: 10.1016/j.celrep.2022.111399] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 06/23/2022] [Accepted: 09/01/2022] [Indexed: 12/20/2022] Open
Abstract
Human metapneumovirus (hMPV) is a major cause of acute respiratory infections in infants and older adults, for which no vaccines or therapeutics are available. The viral fusion (F) glycoprotein is required for entry and is the primary target of neutralizing antibodies; however, little is known about the humoral immune response generated from natural infection. Here, using prefusion-stabilized F proteins to interrogate memory B cells from two older adults, we obtain over 700 paired non-IgM antibody sequences representing 563 clonotypes, indicative of a highly polyclonal response. Characterization of 136 monoclonal antibodies reveals broad recognition of the protein surface, with potently neutralizing antibodies targeting each antigenic site. Cryo-EM studies further reveal two non-canonical sites and the molecular basis for recognition of the apex of hMPV F by two prefusion-specific neutralizing antibodies. Collectively, these results provide insight into the humoral response to hMPV infection in older adults and will help guide vaccine development.
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7
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Profiling of hMPV F-specific antibodies isolated from human memory B cells. Nat Commun 2022; 13:2546. [PMID: 35538099 PMCID: PMC9091222 DOI: 10.1038/s41467-022-30205-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 01/25/2022] [Indexed: 11/09/2022] Open
Abstract
Human metapneumovirus (hMPV) belongs to the Pneumoviridae family and is closely related to respiratory syncytial virus (RSV). The surface fusion (F) glycoprotein mediates viral fusion and is the primary target of neutralizing antibodies against hMPV. Here we report 113 hMPV-F specific monoclonal antibodies (mAbs) isolated from memory B cells of human donors. We characterize the antibodies' germline usage, epitopes, neutralization potencies, and binding specificities. We find that unlike RSV-F specific mAbs, antibody responses to hMPV F are less dominant against the apex of the antigen, and the majority of the potent neutralizing mAbs recognize epitopes on the side of hMPV F. Furthermore, neutralizing epitopes that differ from previously defined antigenic sites on RSV F are identified, and multiple binding modes of site V and II mAbs are discovered. Interestingly, mAbs that bind preferentially to the unprocessed prefusion F show poor neutralization potency. These results elucidate the immune recognition of hMPV infection and provide novel insights for future hMPV antibody and vaccine development.
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8
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Korsun NS, Angelova SG, Trifonova IT, Voleva SE, Grigorova IG, Tzotcheva IS, Mileva SD, Perenovska PI. The Prevalence and Genetic Characterization of Human Metapneumovirus in Bulgaria, 2016-2019. Intervirology 2021; 64:194-202. [PMID: 34304230 DOI: 10.1159/000516821] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 04/21/2021] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION We investigated the prevalence of human metapneumovirus (hMPV) among patients with acute respiratory infections in Bulgaria, and performed genetic characterization of the F gene of these strains. METHODS Nasopharyngeal swabs collected from patients of a range of ages were tested by using real-time PCR for 12 respiratory viruses. The F gene was sequenced, and phylogenetic and amino acid analyses of the F gene/protein were performed. RESULTS A total of 1,842 patients were examined during a 3-year period; 1,229 patients (66.7%) were positive for at least one respiratory virus. hMPV was identified in 83 (4.5%) patient samples. Eleven (13%) of hMPV-positive patients were coinfected with another respiratory virus. The hMPV incidence rate in the 2016/2017, 2017/2018, and 2018/2019 winter seasons was 5.4, 5.4, and 3.1%, respectively. hMPV was mainly detected in specimens collected between January and May (89.2% of cases). The incidence of hMPV infection was highest (5.1%) among the youngest age-group (0-4 years), where hMPV was a causative agent in 8.1 and 4.8% of bronchiolitis and pneumonia cases, respectively. Among the patients aged ≥5 years, hMPV was detected in 2.2 and 3.2% of cases of pneumonia and central nervous system infections, respectively. Phylogenetic analysis of the F gene showed that the sequenced hMPV strains belonged to the A2b, B1, and B2 genotypes. Numerous amino acid substitutions were identified compared with the NL00/1 prototype strain. CONCLUSION This study revealed the significant role of hMPV as a causative agent of serious respiratory illnesses in early childhood, and also demonstrated year-to-year changes in hMPV prevalence and genetic diversity in circulating strains.
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Affiliation(s)
- Neli S Korsun
- Department of Virology, National Center of Infectious and Parasitic Diseases, Sofia, Bulgaria
| | - Svetla G Angelova
- Department of Virology, National Center of Infectious and Parasitic Diseases, Sofia, Bulgaria
| | - Ivelina T Trifonova
- Department of Virology, National Center of Infectious and Parasitic Diseases, Sofia, Bulgaria
| | - Silvia E Voleva
- Department of Virology, National Center of Infectious and Parasitic Diseases, Sofia, Bulgaria
| | - Iliana G Grigorova
- Department of Virology, National Center of Infectious and Parasitic Diseases, Sofia, Bulgaria
| | - Iren S Tzotcheva
- Pediatric Clinic, University Hospital Alexandrovska, Medical University, Sofia, Bulgaria
| | - Sirma D Mileva
- Pediatric Clinic, University Hospital Alexandrovska, Medical University, Sofia, Bulgaria
| | - Penka I Perenovska
- Pediatric Clinic, University Hospital Alexandrovska, Medical University, Sofia, Bulgaria
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9
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Pharmacological Characterization of TP0591816, a Novel Macrocyclic Respiratory Syncytial Virus Fusion Inhibitor with Antiviral Activity against F Protein Mutants. Antimicrob Agents Chemother 2020; 65:AAC.01407-20. [PMID: 33046486 DOI: 10.1128/aac.01407-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 10/01/2020] [Indexed: 11/20/2022] Open
Abstract
Human respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infections in early childhood. However, no vaccines have yet been approved for prevention of RSV infection, and the treatment options are limited. Therefore, development of effective and safe anti-RSV drugs is needed. In this study, we evaluated the antiviral activity and mechanism of action of a novel macrocyclic anti-RSV compound, TP0591816. TP0591816 showed significant antiviral activities against both subgroup A and subgroup B RSV, while exerting no cytotoxicity. Notably, the antiviral activity of TP0591816 was maintained against a known fusion inhibitor-resistant RSV strain with a mutation in the cysteine-rich region or in heptad repeat B. Results of a time-of-addition assay and a temperature shift assay indicated that TP0591816 inhibited fusion of RSV with the cell membrane during viral entry. In addition, TP0591816 added after cell infection also inhibited cell-cell fusion. A TP0591816-resistant virus strain selected by serial passage had an L141F mutation, but no mutation in the cysteine-rich region or in heptad repeat B in the fusion (F) protein. Treatment with TP0591816 reduced lung virus titers in a dose-dependent manner in a mouse model of RSV infection. Furthermore, the estimated effective dose of TP0591816 for use against F protein mutants was thought to be clinically realistic and potentially tolerable. Taken together, these findings suggest that TP0591816 is a promising novel candidate for the treatment of resistant RSV infection.
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10
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Solís-Rodríguez M, Alpuche-Solís ÁG, Tirado-Mendoza RG. Metapneumovirus humano: epidemiología y posibles tratamientos profilácticos. REVISTA DE LA FACULTAD DE MEDICINA 2020. [DOI: 10.22201/fm.24484865e.2020.63.3.02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
In 2001 in the Netherlands, Human metapneumovirus (hMPV) was identified as a “new” etiologic agent causing acute respiratory infections in children younger than 5 years old;
however, it has also been isolated in the elderly and immunocompromised people. This virus is considered the second etiological agent in acute diseases of the respiratory tract. Currently, the estimated cost of IRAs in our country is of 9,000USD per inpatient.
hMPV is a member of the genus Metapneumovirus, family Pneumoviridae, and it belongs to the order Mononegavirales that is part of the negative single-stranded ribonucleic acid (RNA) virus, consisting of eight genes ordered: 3’-N-P-M-FM2-SH-G-L-5 ‘, and which encodes for 9 proteins. Of these proteins, the F fusion glycoprotein is highly conserved in the genus Metapneumovirus, and is the major antigenic determinant, and because an approved vaccine doesn’t exist, it has been used as a candidate epitope for the design of a vaccine that confers host immunity or as a therapeutic target in the creation of antiviral peptides that inhibit the fusion of the virus to its target cell and to avoid infection in subjects at high risk of contagion since there is currently none accepted by COFEPRIS as a prophylactic treatment against hMPV.
Key words: hMPV; respiratory infections; epitopes; protein F;vaccines.
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Affiliation(s)
- Marcela Solís-Rodríguez
- Instituto Potosino de Investigación Científica y Tecnológica (IPICYT). Laboratorio de Biología Molecular de Plantas. San Luis Potosí, S.L.P., México
| | - Ángel G. Alpuche-Solís
- Instituto Potosino de Investigación Científica y Tecnológica (IPICYT). Laboratorio de Biología Molecular de Plantas. San Luis Potosí, S.L.P., México
| | - Rocío G. Tirado-Mendoza
- Universidad Nacional Autónoma de México (UNAM). Facultad de Medicina. Departamento de Microbiología y Parasitología. Laboratorio de Biología del Citoesqueleto y Virología. Ciudad de México. México
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11
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Ogonczyk Makowska D, Hamelin MÈ, Boivin G. Engineering of Live Chimeric Vaccines against Human Metapneumovirus. Pathogens 2020; 9:E135. [PMID: 32093057 PMCID: PMC7168645 DOI: 10.3390/pathogens9020135] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 02/12/2020] [Accepted: 02/14/2020] [Indexed: 02/07/2023] Open
Abstract
Human metapneumovirus (HMPV) is an important human pathogen that, along with respiratory syncytial virus (RSV), is a major cause of respiratory tract infections in young infants. Development of an effective vaccine against Pneumoviruses has proven to be particularly difficult; despite over 50 years of research in this field, no vaccine against HMPV or RSV is currently available. Recombinant chimeric viruses expressing antigens of other viruses can be generated by reverse genetics and used for simultaneous immunization against more than one pathogen. This approach can result in the development of promising vaccine candidates against HMPV, and several studies have indeed validated viral vectors expressing HMPV antigens. In this review, we summarize current efforts in generating recombinant chimeric vaccines against HMPV, and we discuss their potential optimization based on the correspondence with RSV studies.
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Affiliation(s)
| | | | - Guy Boivin
- Centre de Recherche en Infectiologie of the Centre Hospitalier Universitaire de Québec and Université Laval, Québec, QC G1V 4G2, Canada; (D.O.M.); (M.-È.H.)
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12
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Abstract
Influenza and other respiratory viruses are commonly identified in patients with community-acquired pneumonia, hospital-acquired pneumonia, and in immunocompromised patients with pneumonia. Clinically, it is difficult to differentiate viral from bacterial pneumonia. Similarly, the radiological findings of viral infection are nonspecific. The advent of polymerase chain reaction testing has enormously facilitated the identification of respiratory viruses, which has important implications for infection control measures and treatment. Currently, treatment options for patients with viral infection are limited, but there is ongoing research on the development and clinical testing of new treatment regimens and strategies.
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Affiliation(s)
- Rodrigo Cavallazzi
- Division of Pulmonary, Critical Care, and Sleep Disorders, University of Louisville, 550 South Jackson Street, ACB, A3R27, Louisville, KY 40202, USA.
| | - Julio A Ramirez
- Division of Infectious Diseases, University of Louisville, Med Center One, 501 E. Broadway Suite 100, Louisville, KY 40202, USA
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13
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Cockerill GS, Good JAD, Mathews N. State of the Art in Respiratory Syncytial Virus Drug Discovery and Development. J Med Chem 2018; 62:3206-3227. [DOI: 10.1021/acs.jmedchem.8b01361] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- G. Stuart Cockerill
- ReViral Ltd., Stevenage Bioscience Catalyst, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2FX, United Kingdom
| | - James A. D. Good
- ReViral Ltd., Stevenage Bioscience Catalyst, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2FX, United Kingdom
| | - Neil Mathews
- ReViral Ltd., Stevenage Bioscience Catalyst, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2FX, United Kingdom
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14
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Nicholson EG, Munoz FM. A Review of Therapeutics in Clinical Development for Respiratory Syncytial Virus and Influenza in Children. Clin Ther 2018; 40:1268-1281. [PMID: 30077340 DOI: 10.1016/j.clinthera.2018.06.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/15/2018] [Accepted: 06/21/2018] [Indexed: 01/17/2023]
Abstract
PURPOSE Respiratory syncytial virus (RSV) and influenza are important viral pathogens worldwide. Children, in particular, bear considerable burdens of morbidity and mortality associated with these viruses. There are limited therapeutic options for children infected with RSV or influenza. This review focuses on therapeutics for RSV and influenza that are currently under clinical investigation. METHODS This study used a systematic approach to identify prospective therapeutics in clinical trials and briefly reviewed those that are currently available for use in adults and children. FINDINGS Overall, we found 14 investigational drugs currently in clinical trials for RSV and 20 investigation drugs currently in clinical trials for influenza. These candidates range in development from Phase I to Phase III clinical trials. IMPLICATIONS Both RSV and influenza are targets for active therapeutic research, and promising candidates for both viruses are currently in clinical development.
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Affiliation(s)
- Erin G Nicholson
- Departments of Pediatrics and Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas.
| | - Flor M Munoz
- Departments of Pediatrics and Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas
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Olmedillas E, Cano O, Martínez I, Luque D, Terrón MC, McLellan JS, Melero JA, Más V. Chimeric Pneumoviridae fusion proteins as immunogens to induce cross-neutralizing antibody responses. EMBO Mol Med 2018; 10:175-187. [PMID: 29217660 PMCID: PMC5801496 DOI: 10.15252/emmm.201708078] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 10/30/2017] [Accepted: 11/08/2017] [Indexed: 11/09/2022] Open
Abstract
Human respiratory syncytial virus (hRSV) and human metapneumovirus (hMPV), two members of the Pneumoviridae family, account for the majority of severe lower respiratory tract infections worldwide in very young children. They are also a frequent cause of morbidity and mortality in the elderly and immunocompromised adults. High levels of neutralizing antibodies, mostly directed against the viral fusion (F) glycoprotein, correlate with protection against either hRSV or hMPV However, no cross-neutralization is observed in polyclonal antibody responses raised after virus infection or immunization with purified F proteins. Based on crystal structures of hRSV F and hMPV F, we designed chimeric F proteins in which certain residues of well-characterized antigenic sites were swapped between the two antigens. The antigenic changes were monitored by ELISA with virus-specific monoclonal antibodies. Inoculation of mice with these chimeras induced polyclonal cross-neutralizing antibody responses, and mice were protected against challenge with the virus used for grafting of the heterologous antigenic site. These results provide a proof of principle for chimeric fusion proteins as single immunogens that can induce cross-neutralizing antibody and protective responses against more than one human pneumovirus.
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Affiliation(s)
- Eduardo Olmedillas
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
| | - Olga Cano
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
| | - Isidoro Martínez
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
| | - Daniel Luque
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
| | - María C Terrón
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
| | - Jason S McLellan
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - José A Melero
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
| | - Vicente Más
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
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Krivitskaya VZ, Sintsova KS, Petrova ER, Sverlova MV, Sorokin EV, Tsareva TR, Komissarov AB, Fadeev AV, Pisareva MM, Buzitskaya ZV, Afanaseva VS, Sukhovetskaya VF, Sominina AA. GENETIC AND ANTIGENIC CHARACTERISTICS OF RESPIRATORY SYNCYTIAL VIRUS STRAINS ISOLATED IN ST. PETERSBURG IN 2013-2016. Vopr Virusol 2017; 62:273-282. [PMID: 36494959 DOI: 10.18821/0507-4088-2017-62-6-273-282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Indexed: 12/13/2022]
Abstract
Antigenic and genetic characteristics of Russian RSV isolates are presented for the first time. Of the 69 strains isolated in St. Petersburg, 93% belonged to the RSV-A antigenic group. The antigenic variations in the F-protein RSV were analyzed using a panel from 6 monoclonal antibodies by the method of micro-cultural ELISA. Depending on the decrease in the effectiveness of interaction with monoclonal antibodies (relative to the reference strain Long), RSV-A isolates were divided into 4 antigenic subgroups. The results of 24 isolates sequencing showed that more than 60% of them had substitutions in significant F-protein sites compared to the ON67-1210A reference strain of the current RSV genotype ON1/GA2. The most variable were the signal peptide and antigenic site II. When comparing the results of ELISA and sequencing, it was not possible to identify any specific key substitutions in the amino acid sequence of the F-protein that affect the interaction of the virus with antibodies. The nucleotide sequence of the F-gene from 19 of the 24 characterized isolates was close to that of ON67-1210A reference virus and was significantly different from RSV-A Long and A2 viruses. A separate group consisted of 5 strains, in which the F-protein structure was approximated to RSV Long.
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Battles MB, Más V, Olmedillas E, Cano O, Vázquez M, Rodríguez L, Melero JA, McLellan JS. Structure and immunogenicity of pre-fusion-stabilized human metapneumovirus F glycoprotein. Nat Commun 2017; 8:1528. [PMID: 29142300 PMCID: PMC5688127 DOI: 10.1038/s41467-017-01708-9] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/06/2017] [Indexed: 01/10/2023] Open
Abstract
Human metapneumovirus (hMPV) is a frequent cause of bronchiolitis in young children. Its F glycoprotein mediates virus-cell membrane fusion and is the primary target of neutralizing antibodies. The inability to produce recombinant hMPV F glycoprotein in the metastable pre-fusion conformation has hindered structural and immunological studies. Here, we engineer a pre-fusion-stabilized hMPV F ectodomain and determine its crystal structure to 2.6 Å resolution. This structure reveals molecular determinants of strain-dependent acid-induced fusion, as well as insights into refolding from pre- to post-fusion conformations. A dense glycan shield at the apex of pre-fusion hMPV F suggests that antibodies against this site may not be elicited by host immune responses, which is confirmed by depletion studies of human immunoglobulins and by mouse immunizations. This is a major difference with pre-fusion F from human respiratory syncytial virus (hRSV), and collectively our results should facilitate development of effective hMPV vaccine candidates.
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Affiliation(s)
- Michael B Battles
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, 03755, USA
| | - Vicente Más
- Unidad de Biología Viral, Centro Nacional de Microbiología and CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, 28220, Madrid, Spain
| | - Eduardo Olmedillas
- Unidad de Biología Viral, Centro Nacional de Microbiología and CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, 28220, Madrid, Spain
| | - Olga Cano
- Unidad de Biología Viral, Centro Nacional de Microbiología and CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, 28220, Madrid, Spain
| | - Mónica Vázquez
- Unidad de Biología Viral, Centro Nacional de Microbiología and CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, 28220, Madrid, Spain
| | - Laura Rodríguez
- Unidad de Biología Viral, Centro Nacional de Microbiología and CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, 28220, Madrid, Spain.,University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - José A Melero
- Unidad de Biología Viral, Centro Nacional de Microbiología and CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, 28220, Madrid, Spain.
| | - Jason S McLellan
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, 03755, USA.
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Genomic Loads and Genotypes of Respiratory Syncytial Virus: Viral Factors during Lower Respiratory Tract Infection in Chilean Hospitalized Infants. Int J Mol Sci 2017; 18:ijms18030654. [PMID: 28335547 PMCID: PMC5372666 DOI: 10.3390/ijms18030654] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 03/02/2017] [Accepted: 03/13/2017] [Indexed: 11/17/2022] Open
Abstract
The clinical impact of viral factors (types and viral loads) during respiratory syncytial virus (RSV) infection is still controversial, especially regarding newly described genotypes. In this study, infants with RSV bronchiolitis were recruited to describe the association of these viral factors with severity of infection. RSV antigenic types, genotypes, and viral loads were determined from hospitalized patients at Hospital Roberto del Río, Santiago, Chile. Cases were characterized by demographic and clinical information, including days of lower respiratory symptoms and severity. A total of 86 patients were included: 49 moderate and 37 severe cases. During 2013, RSV-A was dominant (86%). RSV-B predominated in 2014 (92%). Phylogenetic analyses revealed circulation of GA2, Buenos Aires (BA), and Ontario (ON) genotypes. No association was observed between severity of infection and RSV group (p = 0.69) or genotype (p = 0.87). After a clinical categorization of duration of illness, higher RSV genomic loads were detected in infants evaluated earlier in their disease (p < 0.001) and also in infants evaluated later, but coursing a more severe infection (p = 0.04). Although types and genotypes did not associate with severity in our children, higher RSV genomic loads and delayed viral clearance in severe patients define a group that might benefit from new antiviral therapies.
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Más V, Rodriguez L, Olmedillas E, Cano O, Palomo C, Terrón MC, Luque D, Melero JA, McLellan JS. Engineering, Structure and Immunogenicity of the Human Metapneumovirus F Protein in the Postfusion Conformation. PLoS Pathog 2016; 12:e1005859. [PMID: 27611367 PMCID: PMC5017722 DOI: 10.1371/journal.ppat.1005859] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Accepted: 08/10/2016] [Indexed: 12/03/2022] Open
Abstract
Human metapneumovirus (hMPV) is a paramyxovirus that is a common cause of bronchiolitis and pneumonia in children less than five years of age. The hMPV fusion (F) glycoprotein is the primary target of neutralizing antibodies and is thus a critical vaccine antigen. To facilitate structure-based vaccine design, we stabilized the ectodomain of the hMPV F protein in the postfusion conformation and determined its structure to a resolution of 3.3 Å by X-ray crystallography. The structure resembles an elongated cone and is very similar to the postfusion F protein from the related human respiratory syncytial virus (hRSV). In contrast, significant differences were apparent with the postfusion F proteins from other paramyxoviruses, such as human parainfluenza type 3 (hPIV3) and Newcastle disease virus (NDV). The high similarity of hMPV and hRSV postfusion F in two antigenic sites targeted by neutralizing antibodies prompted us to test for antibody cross-reactivity. The widely used monoclonal antibody 101F, which binds to antigenic site IV of hRSV F, was found to cross-react with hMPV postfusion F and neutralize both hRSV and hMPV. Despite the cross-reactivity of 101F and the reported cross-reactivity of two other antibodies, 54G10 and MPE8, we found no detectable cross-reactivity in the polyclonal antibody responses raised in mice against the postfusion forms of either hMPV or hRSV F. The postfusion-stabilized hMPV F protein did, however, elicit high titers of hMPV-neutralizing activity, suggesting that it could serve as an effective subunit vaccine. Structural insights from these studies should be useful for designing novel immunogens able to induce wider cross-reactive antibody responses.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/immunology
- Antibodies, Neutralizing/immunology
- Antibodies, Viral/immunology
- Antigens, Viral/chemistry
- Antigens, Viral/genetics
- Antigens, Viral/immunology
- Cross Reactions
- Crystallography, X-Ray
- Female
- Genetic Engineering
- Humans
- Metapneumovirus/genetics
- Metapneumovirus/immunology
- Mice
- Mice, Inbred BALB C
- Models, Molecular
- Molecular Conformation
- Respiratory Syncytial Virus, Human/genetics
- Respiratory Syncytial Virus, Human/immunology
- Sequence Alignment
- Viral Fusion Proteins/chemistry
- Viral Fusion Proteins/genetics
- Viral Fusion Proteins/immunology
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Affiliation(s)
- Vicente Más
- Unidad de Biología Viral, Centro Nacional de Microbiología and CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Laura Rodriguez
- Unidad de Biología Viral, Centro Nacional de Microbiología and CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Eduardo Olmedillas
- Unidad de Biología Viral, Centro Nacional de Microbiología and CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Olga Cano
- Unidad de Biología Viral, Centro Nacional de Microbiología and CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Concepción Palomo
- Unidad de Biología Viral, Centro Nacional de Microbiología and CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - María C. Terrón
- Unidad de Microscopía Electrónica y Confocal, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Daniel Luque
- Unidad de Microscopía Electrónica y Confocal, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - José A. Melero
- Unidad de Biología Viral, Centro Nacional de Microbiología and CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Jason S. McLellan
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
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Fearns R, Deval J. New antiviral approaches for respiratory syncytial virus and other mononegaviruses: Inhibiting the RNA polymerase. Antiviral Res 2016; 134:63-76. [PMID: 27575793 DOI: 10.1016/j.antiviral.2016.08.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 07/27/2016] [Accepted: 08/07/2016] [Indexed: 11/16/2022]
Abstract
Worldwide, respiratory syncytial virus (RSV) causes severe disease in infants, the elderly, and immunocompromised people. No vaccine or effective antiviral treatment is available. RSV is a member of the non-segmented, negative-strand (NNS) group of RNA viruses and relies on its RNA-dependent RNA polymerase to transcribe and replicate its genome. Because of its essential nature and unique properties, the RSV polymerase has proven to be a good target for antiviral drugs, with one compound, ALS-8176, having already achieved clinical proof-of-concept efficacy in a human challenge study. In this article, we first provide an overview of the role of the RSV polymerase in viral mRNA transcription and genome replication. We then review past and current approaches to inhibiting the RSV polymerase, including use of nucleoside analogs and non-nucleoside inhibitors. Finally, we consider polymerase inhibitors that hold promise for treating infections with other NNS RNA viruses, including measles and Ebola.
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Affiliation(s)
- Rachel Fearns
- Department of Microbiology, Boston University School of Medicine, Boston, MA, USA.
| | - Jerome Deval
- Alios BioPharma, Inc., Part of the Janssen Pharmaceutical Companies, South San Francisco, CA, USA.
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Characterization of Epitope-Specific Anti-Respiratory Syncytial Virus (Anti-RSV) Antibody Responses after Natural Infection and after Vaccination with Formalin-Inactivated RSV. J Virol 2016; 90:5965-5977. [PMID: 27099320 DOI: 10.1128/jvi.00235-16] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 04/12/2016] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED Antibodies against the fusion (F) protein of respiratory syncytial virus (RSV) play an important role in the protective immune response to this important respiratory virus. Little is known, however, about antibody levels against multiple F-specific epitopes induced by infection or after vaccination against RSV, while this is important to guide the evaluation of (novel) vaccines. In this study, we analyzed antibody levels against RSV proteins and F-specific epitopes in human sera and in sera of vaccinated and experimentally infected cotton rats and the correlation thereof with virus neutralization. Analysis of human sera revealed substantial diversity in antibody levels against F-, G (attachment)-, and F-specific epitopes between individuals. The highest correlation with virus neutralization was observed for antibodies recognizing prefusion-specific antigenic site Ø. Nevertheless, our results indicate that high levels of antibodies targeting other parts of the F protein can also mediate a potent antiviral antibody response. In agreement, sera of experimentally infected cotton rats contained high neutralizing activity despite lacking antigenic site Ø-specific antibodies. Strikingly, vaccination with formalin-inactivated RSV (FI-RSV) exclusively resulted in the induction of poorly neutralizing antibodies against postfusion-specific antigenic site I, although antigenic sites I, II, and IV were efficiently displayed in FI-RSV. The apparent immunodominance of antigenic site I in FI-RSV likely explains the low levels of neutralizing antibodies upon vaccination and challenge and may play a role in the vaccination-induced enhancement of disease observed with such preparations. IMPORTANCE RSV is an importance cause of hospitalization of infants. The development of a vaccine against RSV has been hampered by the disastrous results obtained with FI-RSV vaccine preparations in the 1960s that resulted in vaccination-induced enhancement of disease. To get a better understanding of the antibody repertoire induced after infection or after vaccination against RSV, we investigated antibody levels against fusion (F) protein, attachment (G) protein, and F-specific epitopes in human and animal sera. The results indicate the importance of prefusion-specific antigenic site Ø antibodies as well as of antibodies targeting other epitopes in virus neutralization. However, vaccination of cotton rats with FI-RSV specifically resulted in the induction of weakly neutralizing, antigenic site I-specific antibodies, which may play a role in the enhancement of disease observed after vaccination with such preparations.
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Influence of Respiratory Syncytial Virus F Glycoprotein Conformation on Induction of Protective Immune Responses. J Virol 2016; 90:5485-5498. [PMID: 27009962 DOI: 10.1128/jvi.00338-16] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Accepted: 03/18/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Human respiratory syncytial virus (hRSV) vaccine development has received new impetus from structure-based studies of its main protective antigen, the fusion (F) glycoprotein. Three soluble forms of F have been described: monomeric, trimeric prefusion, and trimeric postfusion. Most human neutralizing antibodies recognize epitopes found exclusively in prefusion F. Although prefusion F induces higher levels of neutralizing antibodies than does postfusion F, postfusion F can also induce protection against virus challenge in animals. However, the immunogenicity and protective efficacy of the three forms of F have not hitherto been directly compared. Hence, BALB/c mice were immunized with a single dose of the three proteins adjuvanted with CpG and challenged 4 weeks later with virus. Serum antibodies, lung virus titers, weight loss, and pulmonary pathology were evaluated after challenge. Whereas small amounts of postfusion F were sufficient to protect mice, larger amounts of monomeric and prefusion F proteins were required for protection. However, postfusion and monomeric F proteins were associated with more pathology after challenge than was prefusion F. Antibodies induced by all doses of prefusion F, in contrast to other F protein forms, reacted predominantly with the prefusion F conformation. At high doses, prefusion F also induced the highest titers of neutralizing antibodies, and all mice were protected, yet at low doses of the immunogen, these antibodies neutralized virus poorly, and mice were not protected. These findings should be considered when developing new hRSV vaccine candidates. IMPORTANCE Protection against hRSV infection is afforded mainly by neutralizing antibodies, which recognize mostly epitopes found exclusively in the viral fusion (F) glycoprotein trimer, folded in its prefusion conformation, i.e., before activation for membrane fusion. Although prefusion F is able to induce high levels of neutralizing antibodies, highly stable postfusion F (found after membrane fusion) is also able to induce neutralizing antibodies and protect against infection. In addition, a monomeric form of hRSV F that shares epitopes with prefusion F was recently reported. Since each of the indicated forms of hRSV F may have advantages and disadvantages for the development of safe and efficacious subunit vaccines, a direct comparison of the immunogenic properties and protective efficacies of the different forms of hRSV F was made in a mouse model. The results obtained show important differences between the noted immunogens that should be borne in mind when considering the development of hRSV vaccines.
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Melero JA. Influence of antigen conformation and mode of presentation on the antibody and protective responses against human respiratory syncytial virus: relevance for vaccine development. Expert Rev Vaccines 2016; 15:1319-25. [DOI: 10.1080/14760584.2016.1175941] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Abstract
Human metapneumovirus (HMPV) has been described as an important etiologic agent of upper and lower respiratory tract infections, especially in young children and the elderly. Most of school-aged children might be introduced to HMPVs, and exacerbation with other viral or bacterial super-infection is common. However, our understanding of the molecular evolution of HMPVs remains limited. To address the comprehensive evolutionary dynamics of HMPVs, we report a genome-wide analysis of the eight genes (N, P, M, F, M2, SH, G, and L) using 103 complete genome sequences. Phylogenetic reconstruction revealed that the eight genes from one HMPV strain grouped into the same genetic group among the five distinct lineages (A1, A2a, A2b, B1, and B2). A few exceptions of phylogenetic incongruence might suggest past recombination events, and we detected possible recombination breakpoints in the F, SH, and G coding regions. The five genetic lineages of HMPVs shared quite remote common ancestors ranging more than 220 to 470 years of age with the most recent origins for the A2b sublineage. Purifying selection was common, but most protein genes except the F and M2-2 coding regions also appeared to experience episodic diversifying selection. Taken together, these suggest that the five lineages of HMPVs maintain their individual evolutionary dynamics and that recombination and selection forces might work on shaping the genetic diversity of HMPVs.
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