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Frontiers in Immunology 2024Human respiratory viruses are the most prevalent cause of disease in humans, with the highly infectious RSV being the leading cause of infant bronchiolitis and viral...
Human respiratory viruses are the most prevalent cause of disease in humans, with the highly infectious RSV being the leading cause of infant bronchiolitis and viral pneumonia. Responses to type I IFNs are the primary defense against viral infection. However, RSV proteins have been shown to antagonize type I IFN-mediated antiviral innate immunity, specifically dampening intracellular IFN signaling. Respiratory epithelial cells are the main target for RSV infection. In this study, we found RSV-NS1 interfered with the IFN-α JAK/STAT signaling pathway of epithelial cells. RSV-NS1 expression significantly enhanced IFN-α-mediated phosphorylation of STAT1, but not pSTAT2; and neither STAT1 nor STAT2 total protein levels were affected by RSV-NS1. However, expression of RSV-NS1 significantly reduced ISRE and GAS promoter activity and anti-viral IRG expression. Further mechanistic studies demonstrated RSV-NS1 bound STAT1, with protein modeling indicating a possible interaction site between STAT1 and RSV-NS1. Nuclear translocation of STAT1 was reduced in the presence of RSV-NS1. Additionally, STAT1's interaction with the nuclear transport adapter protein, KPNA1, was also reduced, suggesting a mechanism by which RSV blocks STAT1 nuclear translocation. Indeed, reducing STAT1's access to the nucleus may explain RSV's suppression of IFN JAK/STAT promoter activation and antiviral gene induction. Taken together these results describe a novel mechanism by which RSV controls antiviral IFN-α JAK/STAT responses, which enhances our understanding of RSV's respiratory disease progression.
Topics: STAT1 Transcription Factor; Humans; Signal Transduction; Interferon-alpha; Respiratory Syncytial Virus, Human; Viral Nonstructural Proteins; Respiratory Syncytial Virus Infections; Janus Kinases; Cell Nucleus; Phosphorylation; Active Transport, Cell Nucleus; Cell Line
PubMed: 38938568
DOI: 10.3389/fimmu.2024.1395809 -
Viruses Jun 2024This study aimed to determine the incidence and etiological, seasonal, and genetic characteristics of respiratory viral coinfections involving severe acute respiratory...
This study aimed to determine the incidence and etiological, seasonal, and genetic characteristics of respiratory viral coinfections involving severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Between October 2020 and January 2024, nasopharyngeal samples were collected from 2277 SARS-CoV-2-positive patients. Two multiplex approaches were used to detect and sequence SARS-CoV-2, influenza A/B viruses, and other seasonal respiratory viruses: multiplex real-time polymerase chain reaction (PCR) and multiplex next-generation sequencing. Coinfections of SARS-CoV-2 with other respiratory viruses were detected in 164 (7.2%) patients. The most common co-infecting virus was respiratory syncytial virus (RSV) (38 cases, 1.7%), followed by bocavirus (BoV) (1.2%) and rhinovirus (RV) (1.1%). Patients ≤ 16 years of age had the highest rate (15%) of mixed infections. Whole-genome sequencing produced 19 complete genomes of seasonal respiratory viral co-pathogens, which were subjected to phylogenetic and amino acid analyses. The detected influenza viruses were classified into the genetic groups 6B.1A.5a.2a and 6B.1A.5a.2a.1 for A(H1N1)pdm09, 3C.2a1b.2a.2a.1 and 3C.2a.2b for A(H3N2), and V1A.3a.2 for the B/Victoria lineage. The RSV-B sequences belonged to the genetic group GB5.0.5a, with HAdV-C belonging to type 1, BoV to genotype VP1, and PIV3 to lineage 1a(i). Multiple amino acid substitutions were identified, including at the antibody-binding sites. This study provides insights into respiratory viral coinfections involving SARS-CoV-2 and reinforces the importance of genetic characterization of co-pathogens in the development of therapeutic and preventive strategies.
Topics: Humans; Coinfection; SARS-CoV-2; COVID-19; Middle Aged; Adult; Female; Male; Adolescent; Phylogeny; Child, Preschool; Child; Aged; Young Adult; Infant; Respiratory Tract Infections; Rhinovirus; Influenza A virus; Respiratory Syncytial Virus, Human; Nasopharynx; Whole Genome Sequencing; China; Seasons; Aged, 80 and over; Genome, Viral; Influenza B virus
PubMed: 38932250
DOI: 10.3390/v16060958 -
Viruses Jun 2024Recently, respiratory syncytial virus (RSV) vaccines based on the prefusion F (pre-F) antigen were approved in the United States. We aimed to develop an enzyme-linked...
Recently, respiratory syncytial virus (RSV) vaccines based on the prefusion F (pre-F) antigen were approved in the United States. We aimed to develop an enzyme-linked immunosorbent assay (ELISA)-based protocol for the practical and large-scale evaluation of RSV vaccines. Two modified pre-F proteins (DS-Cav1 and SC-TM) were produced by genetic recombination and replication using an adenoviral vector. The protocol was established by optimizing the concentrations of the coating antigen (pre-F proteins), secondary antibodies, and blocking buffer. To validate the protocol, we examined its accuracy, precision, and specificity using serum samples from 150 participants across various age groups and the standard serum provided by the National Institute of Health. In the linear correlation analysis, coating concentrations of 5 and 2.5 μg/mL of DS-Cav1 and SC-TM showed high coefficients of determination (r > 0.90), respectively. Concentrations of secondary antibodies (alkaline phosphatase-conjugated anti-human immunoglobulin G, diluted 1:2000) and blocking reagents (5% skim milk/PBS-T) were optimized to minimize non-specific reactions. High accuracy was observed for DS-Cav1 (r = 0.90) and SC-TM (r = 0.86). Further, both antigens showed high precision (coefficient of variation < 15%). Inhibition ELISA revealed cross-reactivity of antibodies against DS-Cav1 and SC-TM, but not with the attachment (G) protein.
Topics: Enzyme-Linked Immunosorbent Assay; Humans; Respiratory Syncytial Virus Infections; Antibodies, Viral; Respiratory Syncytial Virus Vaccines; Respiratory Syncytial Virus, Human; Infant; Child, Preschool; Adult; Child; Adolescent; Middle Aged; Young Adult; Female; Sensitivity and Specificity; Antigens, Viral; Male; Viral Fusion Proteins; Aged
PubMed: 38932244
DOI: 10.3390/v16060952 -
Viruses Jun 2024Following an interseasonal rise in mainly pediatric respiratory syncytial virus (RSV) cases in Germany in 2021, an exceptionally high number of adult cases was observed...
Respiratory Syncytial Virus in Adult Patients at a Tertiary Care Hospital in Germany: Clinical Features and Molecular Epidemiology of the Fusion Protein in the Severe Respiratory Season of 2022/2023.
Following an interseasonal rise in mainly pediatric respiratory syncytial virus (RSV) cases in Germany in 2021, an exceptionally high number of adult cases was observed in the subsequent respiratory season of 2022/2023. The aim of this study was to compare the clinical presentation of RSV infections in the pre- and post-SARS-CoV-2 pandemic periods. Additionally, the local epidemiology of the RSV fusion protein was analyzed at a molecular genetic and amino acid level. RSV detections in adults peaked in calendar week 1 of 2023, 8 weeks earlier than the earliest peak observed in the three pre-pandemic seasons. Although the median age of the adult patients was not different (66.5 vs. 65 years), subtle differences between both periods regarding comorbidities and the clinical presentation of RSV cases were noted. High rates of comorbidities prevailed; however, significantly lower numbers of patients with a history of lung transplantation ( = 0.009), chronic kidney disease ( = 0.013), and immunosuppression ( = 0.038) were observed in the 2022/2023 season. In contrast, significantly more lower respiratory tract infections ( < 0.001), in particular in the form of pneumonia ( = 0.015) and exacerbations of obstructive lung diseases ( = 0.008), were detected. An ICU admission was noted for 23.7% of all patients throughout the study period. Sequence analysis of the fusion protein gene revealed a close phylogenetic relatedness, regardless of the season of origin. However, especially for RSV-B, an accumulation of amino acid point substitutions was noted, including in antigenic site Ø. The SARS-CoV-2 pandemic had a tremendous impact on the seasonality of RSV, and the introduction of new vaccination and immunization strategies against RSV warrants further epidemiologic studies of this important pathogen.
Topics: Humans; Respiratory Syncytial Virus Infections; Viral Fusion Proteins; Respiratory Syncytial Virus, Human; Germany; Female; Tertiary Care Centers; Aged; Male; Middle Aged; Seasons; COVID-19; Adult; SARS-CoV-2; Molecular Epidemiology; Respiratory Tract Infections; Aged, 80 and over; Young Adult; Phylogeny
PubMed: 38932235
DOI: 10.3390/v16060943 -
Viruses Jun 2024Previous studies from our laboratory and others have established the dendritic cell (DC) as a key target of RSV that drives infection-induced pathology. Analysis of...
Previous studies from our laboratory and others have established the dendritic cell (DC) as a key target of RSV that drives infection-induced pathology. Analysis of RSV-induced transcriptomic changes in RSV-infected DC revealed metabolic gene signatures suggestive of altered cellular metabolism. Reverse phase protein array (RPPA) data showed significantly increased PARP1 phosphorylation in RSV-infected DC. Real-time cell metabolic analysis demonstrated increased glycolysis in PARP1-/- DC after RSV infection, confirming a role for PARP1 in regulating DC metabolism. Our data show that enzymatic inhibition or genomic ablation of PARP1 resulted in increased ifnb1, il12, and il27 in RSV-infected DC which, together, promote a more appropriate anti-viral environment. PARP1-/- mice and PARP1-inhibitor-treated mice were protected against RSV-induced immunopathology including airway inflammation, Th2 cytokine production, and mucus hypersecretion. However, delayed treatment with PARP1 inhibitor in RSV-infected mice provided only partial protection, suggesting that PARP1 is most important during the earlier innate immune stage of RSV infection.
Topics: Animals; Poly (ADP-Ribose) Polymerase-1; Mice; Dendritic Cells; Respiratory Syncytial Virus Infections; Lung; Respiratory Syncytial Viruses; Mice, Knockout; Cytokines; Immunity, Innate; Female
PubMed: 38932202
DOI: 10.3390/v16060910 -
Viruses May 2024Monitoring the genetic variability of human respiratory syncytial virus (hRSV) is of paramount importance, especially for the potential implication of key antigenic...
Monitoring the genetic variability of human respiratory syncytial virus (hRSV) is of paramount importance, especially for the potential implication of key antigenic mutations on the emergence of immune escape variants. Thus, to describe the genetic diversity and evolutionary dynamics of hRSV circulating in Sicily (Italy), a total of 153 hRSV whole-genome sequences collected from 770 hRSV-positive subjects between 2017 and 2023, before the introduction of expanded immunization programs into the population, were investigated. The phylogenetic analyses indicated that the genotypes GA.2.3.5 (ON1) for hRSV-A and GB.5.0.5a (BA9) for hRSV-B co-circulated in our region. Amino acid (AA) substitutions in the surface and internal proteins were evaluated, including the F protein antigenic sites, as the major targets of immunoprophylactic monoclonal antibodies and vaccines. Overall, the proportion of AA changes ranged between 1.5% and 22.6% among hRSV-A, whereas hRSV-B varied in the range 0.8-16.9%; the latter was more polymorphic than hRSV-A within the key antigenic sites. No AA substitutions were found at site III of both subgroups. Although several non-synonymous mutations were found, none of the polymorphisms known to potentially affect the efficacy of current preventive measures were documented. These findings provide new insights into the global hRSV molecular epidemiology and highlight the importance of defining a baseline genomic picture to monitor for future changes that might be induced by the selective pressures of immunological preventive measures, which will soon become widely available.
Topics: Humans; Respiratory Syncytial Virus, Human; Genetic Variation; Respiratory Syncytial Virus Infections; Sicily; Phylogeny; Whole Genome Sequencing; Child, Preschool; Infant; Female; Male; Child; Genotype; Adult; Adolescent; Genome, Viral; Middle Aged; Young Adult; Aged; Influenza, Human; Amino Acid Substitution; Infant, Newborn
PubMed: 38932144
DOI: 10.3390/v16060851 -
Viruses May 2024The social restriction measures implemented due to the COVID-19 pandemic have impacted the pattern of occurrences of respiratory viruses. According to surveillance...
The social restriction measures implemented due to the COVID-19 pandemic have impacted the pattern of occurrences of respiratory viruses. According to surveillance results in the Gwangju region of South Korea, respiratory syncytial virus (RSV) did not occur during the 2020/2021 season. However, there was a delayed resurgence in the 2021/2022 season, peaking until January 2022. To analyze this, a total of 474 RSV positive samples were investigated before and after the COVID-19 pandemic. Among them, 73 samples were selected for whole-genome sequencing. The incidence rate of RSV in the 2021/2022 season after COVID-19 was found to be approximately three-fold higher compared to before the pandemic, with a significant increase observed in the age group from under 2 years old to under 5 years old. Phylogenetic analysis revealed that, for RSV-A, whereas four lineages were observed before COVID-19, only the A.D.3.1 lineage was observed during the 2021/2022 season post-pandemic. Additionally, during the 2022/2023 season, the A.D.1, A.D.3, and A.D.3.1 lineages co-circulated. For RSV-B, while the B.D.4.1.1 lineage existed before COVID-19, both the B.D.4.1.1 and B.D.E.1 lineages circulated after the pandemic. Although atypical RSV occurrences were not due to new lineages, there was an increase in the frequency of mutations in the F protein of RSV after COVID-19. These findings highlight the need to continue monitoring changes in RSV occurrence patterns in the aftermath of the COVID-19 pandemic to develop and manage strategies in response.
Topics: Humans; Republic of Korea; COVID-19; Respiratory Syncytial Virus Infections; Phylogeny; Child, Preschool; Respiratory Syncytial Virus, Human; SARS-CoV-2; Infant; Child; Female; Male; Incidence; Whole Genome Sequencing; Adult; Seasons; Pandemics; Middle Aged; Aged; Infant, Newborn; Adolescent
PubMed: 38932143
DOI: 10.3390/v16060850 -
Viruses May 2024Respiratory syncytial virus (RSV) is a major cause of severe respiratory tract disease worldwide, and a pediatric vaccine is not available. We generated a filamentous...
Intranasal Vaccination with a Respiratory-Syncytial-Virus-Based Virus-like Particle Displaying the G Protein Conserved Region Induces Severe Weight Loss and Pathology upon Challenge with Wildtype Respiratory Syncytial Virus.
Respiratory syncytial virus (RSV) is a major cause of severe respiratory tract disease worldwide, and a pediatric vaccine is not available. We generated a filamentous RSV-based virus-like particle (VLP) that presents the central conserved region of the attachment protein G. This was achieved by co-expressing the matrix protein, phosphoprotein, nucleoprotein, and a hybrid fusion protein in which the F ectodomain was replaced with the G central region (GCR). The latter is relatively conserved and contains a receptor binding site and hence is a logical vaccine target. The immunogenicity and efficacy of the resulting VLP, termed VLP-GCR, were examined in mice using intranasal application without adjuvant. VLP-GCR induced substantial anti-N antibody levels but very low anti-G antibody levels, even after three vaccinations. In contrast, a VLP presenting prefusion-stabilized fusion (preF) protein instead of GCR induced both high anti-F and anti-nucleoprotein antibody levels, suggesting that our GCR antigen was poorly immunogenic. Challenge of VLP-GCR-vaccinated mice caused increased weight loss and lung pathology, and both VLPs induced mucus in the lungs. Thus, neither VLP is suitable as a vaccine for RSV-naive individuals. However, VLP-preF enhanced the proportion of preF antibodies and could serve as a multi-antigen mucosal booster vaccine in the RSV-experienced population.
Topics: Animals; Administration, Intranasal; Respiratory Syncytial Virus Infections; Mice; Vaccines, Virus-Like Particle; Antibodies, Viral; Respiratory Syncytial Virus Vaccines; Female; Mice, Inbred BALB C; Respiratory Syncytial Virus, Human; Vaccination; Weight Loss; Viral Fusion Proteins; Humans; Lung; Viral Envelope Proteins
PubMed: 38932136
DOI: 10.3390/v16060843 -
Viruses May 2024When designing live-attenuated respiratory syncytial virus (RSV) vaccine candidates, attenuating mutations can be developed through biologic selection or reverse-genetic...
When designing live-attenuated respiratory syncytial virus (RSV) vaccine candidates, attenuating mutations can be developed through biologic selection or reverse-genetic manipulation and may include point mutations, codon and gene deletions, and genome rearrangements. Attenuation typically involves the reduction in virus replication, due to direct effects on viral structural and replicative machinery or viral factors that antagonize host defense or cause disease. However, attenuation must balance reduced replication and immunogenic antigen expression. In the present study, we explored a new approach in order to discover attenuating mutations. Specifically, we used protein structure modeling and computational methods to identify amino acid substitutions in the RSV nonstructural protein 1 (NS1) predicted to cause various levels of structural perturbation. Twelve different mutations predicted to alter the NS1 protein structure were introduced into infectious virus and analyzed in cell culture for effects on viral mRNA and protein expression, interferon and cytokine expression, and caspase activation. We found the use of structure-based machine learning to predict amino acid substitutions that reduce the thermodynamic stability of NS1 resulted in various levels of loss of NS1 function, exemplified by effects including reduced multi-cycle viral replication in cells competent for type I interferon, reduced expression of viral mRNAs and proteins, and increased interferon and apoptosis responses.
Topics: Humans; Machine Learning; Viral Nonstructural Proteins; Respiratory Syncytial Virus Vaccines; Respiratory Syncytial Virus, Human; Virus Replication; Vaccines, Attenuated; Respiratory Syncytial Virus Infections; Amino Acid Substitution; Mutation; Cell Line
PubMed: 38932114
DOI: 10.3390/v16060821 -
Communicable Diseases Intelligence... Jun 2024Respiratory syncytial virus (RSV) is the leading cause of bronchiolitis and pneumonia in infants. Little is known about the epidemiology, burden, and seasonality of RSV...
Respiratory syncytial virus (RSV) is the leading cause of bronchiolitis and pneumonia in infants. Little is known about the epidemiology, burden, and seasonality of RSV in subtropical regions of Australia like Central Queensland. This information is important to plan prevention strategies, including therapeutics, future vaccines, and health system preparedness. We collected data on laboratory-confirmed RSV cases and admissions in Central Queensland for the period 1 July 2021 to 31 December 2022. From July 2021, RSV was listed as a nationally notifiable condition on laboratory-confirmed diagnosis. During the study period, 1,142 laboratory-confirmed cases of RSV (50.0% female sex) were reported, with 169 cases (14.8%) requiring hospital admission, 12 of which (7.1%) required intensive care unit/high dependency unit admissions; two deaths occurred. Of cases requiring hospital admission, RSV was listed as the primary diagnosis in 113/169 cases (66.9%); 63/169 admitted cases (37.3%) had a major comorbidity. Of all cases, 55.4% were in children < 5 years of age (20.9% hospitalised); 35.7% in children < 2 years of age (24.3% hospitalised), and 19.1% in children < 12 months of age (27.5% hospitalised). Children under five years of age made up 78.1% of admissions, a rate of 9.0 admissions per 1,000 children over the 18-month study period, with an average age of 15.8 months (standard deviation, SD: 13.1 months) in this cohort. Indigenous children aged < 5 years were over-represented in cases (rate ratio, RR: 1.6; 95% confidence interval [95% CI]: 1.3-1.9) and admissions (RR: 1.6; 95% CI: 1.0-2.4). Antibiotics were prescribed to 48.5% of admitted cases under two years of age, despite documented bacterial infection in only 26.3% of these cases; antibiotic prescription was significantly higher in those who received a chest X-ray (p < 0.001). Of all cases, 33.5% occurred in July 2022 alone, with greater than 75.0% of cases occurring during June-August 2022. RSV showed year-round activity with a distinctive winter peak in 2022; however, this season was likely affected by coronavirus disease 2019 (COVID-19) restrictions and behaviours. Ongoing surveillance is required to better understand the epidemiology and seasonality of RSV in Central Queensland.
Topics: Humans; Respiratory Syncytial Virus Infections; Queensland; Female; Male; Infant; Child, Preschool; Hospitalization; Respiratory Syncytial Virus, Human; Child; Seasons; Adolescent; Infant, Newborn; Adult; Middle Aged
PubMed: 38926651
DOI: 10.33321/cdi.2024.48.45