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Current Opinion in Virology Aug 2023Respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) continue to be a global burden to infants, the elderly, and immunocompromised individuals. In the past... (Review)
Review
Respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) continue to be a global burden to infants, the elderly, and immunocompromised individuals. In the past ten years, there has been substantial progress in the development of new vaccine candidates and therapies against these viruses. These advancements were guided by the structural elucidation of the major surface glycoproteins for these viruses, the fusion (F) protein and attachment (G) protein. The identification of immunodominant epitopes on the RSV F and hMPV F proteins has expanded current knowledge on antibody-mediated immune responses, which has led to new approaches for vaccine and therapeutic development through the stabilization of pre-fusion constructs of the F protein and pre-fusion-specific monoclonal antibodies with high potency and efficacy. In this review, we describe structural characteristics of known antigenic sites on the RSV and hMPV proteins, their influence on the immune response, and current progress in vaccine and therapeutic development.
Topics: Humans; Aged; Metapneumovirus; Antibodies, Viral; Antibodies, Neutralizing; Viral Fusion Proteins; Respiratory Syncytial Virus, Human; Respiratory Syncytial Virus Infections
PubMed: 37544710
DOI: 10.1016/j.coviro.2023.101337 -
Viruses Sep 2023Respiratory syncytial virus (RSV) infections are a constant public health problem, especially in infants and older adults. Virtually all children will have been infected... (Review)
Review
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.
Topics: Infant; Child; Female; Pregnancy; Humans; Aged; Respiratory Syncytial Virus Infections; Reinfection; Respiratory Syncytial Viruses; Immunity; Vaccines; Respiratory Syncytial Virus Vaccines; Respiratory Syncytial Virus, Human
PubMed: 37896776
DOI: 10.3390/v15101999 -
Paediatric Drugs Nov 2023Pfizer is developing a bivalent respiratory syncytial virus (RSV) prefusion F subunit vaccine (RSVpreF; ABRYSVO™) for preventing RSV illness in infants and individuals... (Review)
Review
Pfizer is developing a bivalent respiratory syncytial virus (RSV) prefusion F subunit vaccine (RSVpreF; ABRYSVO™) for preventing RSV illness in infants and individuals aged ≥ 60 years. RSVpreF received approval for vaccination of pregnant individuals to help protect infants against RSV illness on 21 August 2023 in the USA. RSVpreF is also approved in the USA (31 May 2023) for active immunization of individuals aged ≥ 60 years for the prevention of lower respiratory tract disease (LRTD) caused by RSV. In the EU, RSVpreF has received approval for both indications, and it has been submitted for regulatory approval in Canada (both indications) and in Japan (maternal immunization to protect infants). This article summarizes the milestones in the development of RSVpreF leading to the approval for use in pregnant individuals to prevent LRTD in infants.
Topics: Female; Pregnancy; Humans; Infant; Respiratory Syncytial Virus Vaccines; Antibodies, Viral; Viral Fusion Proteins; Respiratory Syncytial Virus Infections; Respiratory Syncytial Viruses; Vaccines, Subunit
PubMed: 37831328
DOI: 10.1007/s40272-023-00598-3 -
Expert Review of Anti-infective Therapy 2023
Topics: Humans; Henipavirus; Disease Outbreaks; Henipavirus Infections
PubMed: 37724512
DOI: 10.1080/14787210.2023.2260561 -
Ugeskrift For Laeger Mar 2024Respiratory syncytial virus (RSV is) a common respiratory virus responsible for considerable morbidity and mortality among infants, elderly with comorbidity, and...
Respiratory syncytial virus (RSV is) a common respiratory virus responsible for considerable morbidity and mortality among infants, elderly with comorbidity, and immunocompromised adults. Two vaccines, Abrysvo and Arexvy, have been approved for prevention of severe RSV infection in adults ≥ 60 years of age. In addition, Abrysvo is approved for use during pregnancy to protect infants from RSV-associated lower respiratory tract infection. Currently, there is no national recommendation for the use of the vaccines, but vaccination of elderly at highest risk of severe RSV infection should be considered in a shared clinical decision making.
Topics: Infant; Adult; Pregnancy; Female; Humans; Aged; Respiratory Syncytial Virus Infections; Respiratory Syncytial Virus Vaccines; Respiratory Syncytial Virus, Human; Viral Vaccines
PubMed: 38533866
DOI: 10.61409/V12230800 -
Science Translational Medicine Aug 2023The RSVPreF3-AS01 vaccine, containing the respiratory syncytial virus (RSV) prefusion F protein and the AS01 adjuvant, was previously shown to boost neutralization...
The RSVPreF3-AS01 vaccine, containing the respiratory syncytial virus (RSV) prefusion F protein and the AS01 adjuvant, was previously shown to boost neutralization responses against historical RSV strains and to be efficacious in preventing RSV-associated lower respiratory tract diseases in older adults. Although RSV F is highly conserved, variation does exist between strains. Here, we characterized variations in the major viral antigenic sites among contemporary RSV sequences when compared with RSVPreF3 and showed that, in older adults, RSVPreF3-AS01 broadly boosts neutralization responses against currently dominant and antigenically distant RSV strains. RSV-neutralizing responses are thought to play a central role in preventing RSV infection. Therefore, the breadth of RSVPreF3-AS01-elicited neutralization responses may contribute to vaccine efficacy against contemporary RSV strains and those that may emerge in the future.
Topics: Humans; Aged; Respiratory Syncytial Viruses; Respiratory Syncytial Virus Infections; Vaccines; Antigens, Viral
PubMed: 37611082
DOI: 10.1126/scitranslmed.adg6050 -
Virulence Dec 2023Paramyxoviruses are a family of single-stranded negative-sense RNA viruses, many of which are responsible for a range of respiratory and neurological diseases in humans... (Review)
Review
Paramyxoviruses are a family of single-stranded negative-sense RNA viruses, many of which are responsible for a range of respiratory and neurological diseases in humans and animals. Among the most notable are the henipaviruses, which include the deadly Nipah (NiV) and Hendra (HeV) viruses, the causative agents of outbreaks of severe disease and high case fatality rates in humans and animals. NiV and HeV are maintained in fruit bat reservoirs primarily in the family and spillover into humans directly or by an intermediate amplifying host such as swine or horses. Recently, non-chiropteran associated Langya (LayV), Gamak (GAKV), and Mojiang (MojV) viruses have been discovered with confirmed or suspected ability to cause disease in humans or animals. These viruses are less genetically related to HeV and NiV yet share many features with their better-known counterparts. Recent advances in surveillance of wild animal reservoir viruses have revealed a high number of henipaviral genome sequences distributed across most continents, and mammalian orders previously unknown to harbour henipaviruses. In this review, we summarize the current knowledge on the range of pathogenesis observed for the henipaviruses as well as their replication cycle, epidemiology, genomics, and host responses. We focus on the most pathogenic viruses, including NiV, HeV, LayV, and GAKV, as well as the experimentally non-pathogenic CedV. We also highlight the emerging threats posed by these and potentially other closely related viruses.
Topics: Animals; Humans; Swine; Horses; Virulence; Henipavirus Infections; Nipah Virus; Hendra Virus; Disease Outbreaks; Chiroptera
PubMed: 37948320
DOI: 10.1080/21505594.2023.2273684 -
Nature Oct 2023Non-segmented negative-strand RNA viruses, including Ebola virus (EBOV), rabies virus, human respiratory syncytial virus and pneumoviruses, can cause respiratory...
Non-segmented negative-strand RNA viruses, including Ebola virus (EBOV), rabies virus, human respiratory syncytial virus and pneumoviruses, can cause respiratory infections, haemorrhagic fever and encephalitis in humans and animals, and are considered a substantial health and economic burden worldwide. Replication and transcription of the viral genome are executed by the large (L) polymerase, which is a promising target for the development of antiviral drugs. Here, using the L polymerase of EBOV as a representative, we show that de novo replication of L polymerase is controlled by the specific 3' leader sequence of the EBOV genome in an enzymatic assay, and that formation of at least three base pairs can effectively drive the elongation process of RNA synthesis independent of the specific RNA sequence. We present the high-resolution structures of the EBOV L-VP35-RNA complex and show that the 3' leader RNA binds in the template entry channel with a distinctive stable bend conformation. Using mutagenesis assays, we confirm that the bend conformation of the RNA is required for the de novo replication activity and reveal the key residues of the L protein that stabilize the RNA conformation. These findings provide a new mechanistic understanding of RNA synthesis for polymerases of non-segmented negative-strand RNA viruses, and reveal important targets for the development of antiviral drugs.
Topics: Animals; Humans; Antiviral Agents; Ebolavirus; Hemorrhagic Fever, Ebola; RNA, Viral; RNA-Dependent RNA Polymerase; Virus Replication; Genome, Viral; Nucleic Acid Conformation; Mutagenesis; RNA Stability
PubMed: 37699521
DOI: 10.1038/s41586-023-06608-1 -
Viruses Sep 2023Hendra virus (HeV) and Nipah virus (NiV) are zoonotic paramyxoviruses in the genus (HNV) that emerged nearly thirty years ago. Outbreaks of HeV and NiV have led to... (Review)
Review
Hendra virus (HeV) and Nipah virus (NiV) are zoonotic paramyxoviruses in the genus (HNV) that emerged nearly thirty years ago. Outbreaks of HeV and NiV have led to severe respiratory disease and encephalitis in humans and animals characterized by a high mortality rate. Despite the grave threat HNVs pose to public health and global biosecurity, no approved medical countermeasures for human use currently exist against HeV or NiV. To develop candidate vaccines and therapeutics and advance the field's understanding of HNV pathogenesis, animal models of HeV and NiV have been instrumental and remain indispensable. Various species, including rodents, ferrets, and nonhuman primates (NHPs), have been employed for HNV investigations. Among these, NHPs have demonstrated the closest resemblance to human HNV disease, although other animal models replicate some key disease features. Here, we provide a comprehensive review of the currently available animal models (mice, hamsters, guinea pigs, ferrets, cats, dogs, nonhuman primates, horses, and swine) to support HNV research. We also discuss the strengths and limitations of each model for conducting pathogenesis and transmission studies on HeV and NiV and for the evaluation of medical countermeasures.
Topics: Cricetinae; Animals; Humans; Guinea Pigs; Horses; Mice; Dogs; Ferrets; Henipavirus Infections; Hendra Virus; Nipah Virus; Disease Models, Animal; Primates
PubMed: 37896758
DOI: 10.3390/v15101980 -
Cell Host & Microbe Aug 2023Respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) infections pose a significant health burden. Using pre-fusion conformation fusion (F) proteins, we...
Respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) infections pose a significant health burden. Using pre-fusion conformation fusion (F) proteins, we isolated a panel of anti-F antibodies from a human donor. One antibody (RSV-199) potently cross-neutralized 8 RSV and hMPV strains by recognizing antigenic site III, which is partially conserved in RSV and hMPV F. Next, we determined the cryoelectron microscopy (cryo-EM) structures of RSV-199 bound to RSV F trimers, hMPV F monomers, and an unexpected dimeric form of hMPV F. These structures revealed how RSV-199 engages both RSV and hMPV F proteins through conserved interactions of the antibody heavy-chain variable region and how variability within heavy-chain complementarity-determining region 3 (HCDR3) can be accommodated at the F protein interface in site-III-directed antibodies. Furthermore, RSV-199 offered enhanced protection against RSV A and B strains and hMPV in cotton rats. These findings highlight the mechanisms of broad neutralization and therapeutic potential of RSV-199.
Topics: Humans; Metapneumovirus; Antibodies, Neutralizing; Antibodies, Viral; Cryoelectron Microscopy; Respiratory Syncytial Virus, Human; Immunoglobulin Variable Region; Viral Fusion Proteins
PubMed: 37516111
DOI: 10.1016/j.chom.2023.07.002