The genomic evolutionary dynamics and global circulation patterns of respiratory syncytial virus.

Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory tract infection in young children and the second leading cause of infant death worldwide. While global circulation has been extensively studied for respiratory viruses such as seasonal influenza, and more recently also in great detail for SARS-CoV-2, a lack of global multi-annual sampling of complete RSV genomes limits our understanding of RSV molecular epidemiology. Here, we capitalise on the genomic surveillance by the INFORM-RSV study and apply phylodynamic approaches to uncover how selection and neutral epidemiological processes shape RSV diversity. Using complete viral genome sequences, we show similar patterns of site-specific diversifying selection among RSVA and RSVB and recover the imprint of non-neutral epidemic processes on their genealogies. Using a phylogeographic approach, we provide evidence for air travel governing the global patterns of RSVA and RSVB spread, which results in a considerable degree of phylogenetic mixing across countries. Our findings highlight the potential of systematic global RSV genomic surveillance for transforming our understanding of global RSV spread.

p53 suppresses the inflammatory response following respiratory syncytial virus infection by inhibiting TLR2.

-Respiratory syncytial virus (RSV) is a pivotal virus leading to acute lower respiratory tract infections in children under 5 years old. This study aimed to explore the correlation between p53 and Toll-like receptors (TLRs) post RSV infection. p53 levels exhibited a substantial decrease in nasopharyngeal aspirates (NPAs) from infants with RSV infection compared to control group. Manipulating p53 expression had no significant impact on RSV replication or interferon signaling pathway. Suppression of p53 expression led to heightened inflammation following RSV infection in A549 cells or airways of BALB/c mice. while stabilizing p53 expression using Nutlin-3a mitigated the inflammatory response in A549 cells. Additionally, Inhibiting p53 expression significantly increased Toll-like receptor 2 (TLR2) expression in RSV-infected epithelial cells and BALB/c mice. Furthermore, the TLR2 inhibitor, C29, effectively reduced inflammation mediated by p53 in A549 cells. Collectively, our results indicate that p53 modulates the inflammatory response after RSV infection through TLR2.

Bacterial small RNAs may mediate immune response differences seen in respiratory syncytial virus versus rhinovirus bronchiolitis.

Bronchiolitis, a viral lower respiratory infection, is the leading cause of infant hospitalization, which is associated with an increased risk for developing asthma later in life. Bronchiolitis can be caused by several respiratory viruses, such as respiratory syncytial virus (RSV), rhinovirus (RV), and others. It can also be caused by a solo infection (e.g., RSV- or RV-only bronchiolitis) or co-infection with two or more viruses. Studies have shown viral etiology-related differences between RSV- and RV-only bronchiolitis in the immune response, human microRNA (miRNA) profiles, and dominance of certain airway microbiome constituents. Here, we identified bacterial small RNAs (sRNAs), the prokaryotic equivalent to eukaryotic miRNAs, that differ between infants of the 35th Multicenter Airway Research Collaboration (MARC-35) cohort with RSV- versus RV-only bronchiolitis. We first derived reference sRNA datasets from cultures of four bacteria known to be associated with bronchiolitis (i.e., Haemophilus influenzae, Moraxella catarrhalis, Moraxella nonliquefaciens, and Streptococcus pneumoniae). Using these reference sRNA datasets, we found several sRNAs associated with RSV- and RV-only bronchiolitis in our human nasal RNA-Seq MARC-35 data. We also determined potential human transcript targets of the bacterial sRNAs and compared expression of the sRNAs between RSV- and RV-only cases. sRNAs are known to downregulate their mRNA target, we found that, compared to those associated with RV-only bronchiolitis, sRNAs associated with RSV-only bronchiolitis may relatively activate the IL-6 and IL-8 pathways and relatively inhibit the IL-17A pathway. These data support that bacteria may be contributing to inflammation differences seen in RSV- and RV-only bronchiolitis, and for the first time indicate that the potential mechanism in doing so may be through bacterial sRNAs.

Epigenetic Control of Innate Immunity: Consequences of Acute Respiratory Virus Infection.

Infections caused by acute respiratory viruses induce a systemic innate immune response, which can be measured by the increased levels of expression of inflammatory genes in immune cells. There is growing evidence that these acute viral infections, alongside transient transcriptomic responses, induce epigenetic remodeling as part of the immune response, such as DNA methylation and histone modifications, which might persist after the infection is cleared. In this article, we first review the primary mechanisms of epigenetic remodeling in the context of innate immunity and inflammation, which are crucial for the regulation of the immune response to viral infections. Next, we delve into the existing knowledge concerning the impact of respiratory virus infections on the epigenome, focusing on Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), Influenza A Virus (IAV), and Respiratory Syncytial Virus (RSV). Finally, we offer perspectives on the potential consequences of virus-induced epigenetic remodeling and open questions in the field that are currently under investigation.

[Study on transcriptome characteristics of respiratory syncytial virus bronchiolitis in children by RNA sequencing].

To explore the biological characteristics related to the pathogenesis and severity of respiratory syncytial virus (RSV) bronchiolitis by RNA sequencing of white blood cells in children with RSV bronchiolitis. This study is a case-control study. A total of 87 children diagnosed with bronchiolitis and RSV antigen positive and/or RSV nucleic acid positive in the pediatric respiratory department of the Second Affiliated Hospital of Wenzhou Medical University from October 2019 to April 2022 were selected as the case group. The case group was divided into three groups based on the condition: mild, moderate, and severe, and there were two groups according to the presence or absence of atopic symptoms: the atopic group and the non-atopic group, forty healthy children in the same period were selected as the control group. The whole blood leukocyte RNA of the children in the case group and the control group was extracted for RNA sequencing, and the data were analyzed to obtain differentially expressed genes (DEGs). Then, the immunobiological pathways and genes related to the pathogenesis, disease condition, and atopy were screened through Gene Ontology (GO) annotation, Kyoto Gene and Genome Encyclopedia (KEGG) annotation, and protein interaction network (PPI) construction methods. Construct the weighted gene co-expression network analysis (WGCNA) module to identify potential biological indicators related to disease severity.Compared with the control group, the case group had a total of 1 782 DEGs, including 1 586 upregulated genes and 196 downregulated genes. The GO pathway enrichment of DEGs is mainly enriched in molecular functions such as peroxidase activity and oxidoreductase activity. In the cytological components, it is mainly enriched in cytoplasmic vesicle lumen and secretory granule lumen. In biological processes, it is mainly enriched in processes such as neutrophil activation involved in immune responses, neutrophil degranulation, and neutrophil activation. KEGG analysis is mainly concentrated in the signal pathway of the viral protein interaction with cytokine and cytokine receptor. A PPI network was constructed to screen four genes at the core position, including CCL2, IL-10, MMP9 and JUN. The DEGs obtained by comparing different disease groups with the control group are mainly enriched in retrograde endocannabinoid signaling and cell apoptosis pathways. WGCNA analysis showed that the brown module related to oxygen saturation was most closely related to the disease, and its gene was mainly enriched in the RNA helicase retinoic acid inducible gene-I (RIG-I) like receptor signal pathway. There are 230 specific DEGs in the atopic group and 444 in the non-atopic group. KEGG enrichment analysis results show that both groups are enriched to NF-κB signaling pathway, the characteristic does not cause significant changes in immune response and transcriptome characteristics in children with RSV bronchiolitis. In conclusion, neutrophil activation, degranulation pathway and signal pathway of interaction between viral protein and cytokine and cytokine receptor are involved in the immune response of RSV bronchiolitis host. CCL2, IL-10, MMP9 and JUN genes may be associated with the pathogenesis. They might be potential biomarkers related to disease severity in RIG-I like receptors, cell apoptosis, and endogenous cannabinoid related signaling pathways.

Airway and Blood Monocyte Transcriptomic Profiling Reveals an Antiviral Phenotype in Infants With Severe Respiratory Syncytial Virus Infection.

BACKGROUND: Respiratory syncytial virus (RSV) infection is the primary cause of lower respiratory tract infections in children <5 years of age. Monocytes, especially in the respiratory tract, are suggested to contribute to RSV pathology, but their role is incompletely understood. With transcriptomic profiling of blood and airway monocytes, we describe the role of monocytes in severe RSV infection. METHODS: Tracheobronchial aspirates and blood samples were collected from control patients (n = 9) and those infected with RSV (n = 14) who were admitted to the pediatric intensive care unit. Monocytes (CD14+) were sorted and analyzed by RNA sequencing for transcriptomic profiling. RESULTS: Peripheral blood and airway monocytes of patients with RSV demonstrated increased expression of antiviral and interferon-responsive genes as compared with controls. Cytokine signaling showed a shared response between blood and airway monocytes while displaying responses that were more pronounced according to the tissue of origin. Airway monocytes upregulated additional genes related to migration and inflammation. CONCLUSIONS: We found that the RSV-induced interferon response extends from the airways to the peripheral blood. Moreover, RSV induces a migration-promoting transcriptional program in monocytes. Unraveling the monocytic response and its role in the immune response to RSV infection could help the development of therapeutics to prevent severe disease.

Low peripheral blood chemokine (C-C motif) ligand 5 and tumor necrosis factor α gene expression is associated with unfavorable progression of respiratory syncytial virus bronchiolitis in infants.

OBJECTIVES: We aimed to analyze whether the expression of inflammatory and antiviral genes in respiratory syncytial virus (RSV)-infected infants' peripheral blood is associated with bronchiolitis progression. METHODS: We conducted a prospective study on 117 infants between 2015 and 2023. The expression levels of nine genes were quantified by quantitative polymerase chain reaction. Infants were classified according to their clinical evolution during hospital admission: (i) non-progression (n = 74), when the RSV bronchiolitis severity remained stable or improved; (ii) unfavorable progression (n = 43), when the RSV bronchiolitis severity increased. The association analysis was performed by logistic regression, adjusted by age, gender, prematurity, and RSV bronchiolitis severity in the emergency room. RESULTS: Infants were 57.3% male, and the median age of the study population was 61 days. Thirty-five infants (30.7%) were admitted to the intensive care unit after hospital admission. Univariate logistic models showed that tumor necrosis factor (TNFα) and chemokine (C-C motif) ligand (CCL5) gene expression at baseline were inversely associated with unfavorable progression, which was confirmed by multivariate analyses: TNFα (adjusted odds ratio = 0.8 [95% confidence interval = 0.64-0.99], P-value = 0.038) and CCL5 (adjusted odds ratio = 0.76 [95% confidence interval = 0.62-0.93], P-value = 0.007). CONCLUSIONS: An inadequate immune response to RSV, characterized by reduced gene expression levels of CCL5 and TNFα in peripheral blood, was associated with an unfavorable progression of RSV bronchiolitis.

Luteolin-7-O-glucoside promotes macrophage release of IFN-ß by maintaining mitochondrial function and corrects the disorder of glucose metabolism during RSV infection.

Respiratory syncytial virus (RSV) pneumonia is the main cause of acute bronchiolitis in infants. Luteolin-7-O-glucoside (LUT-7G) is a natural flavonoid, which exists in a variety of plants and has the potential to treat viral pneumonia. We established RSV pneumonia mouse models and RSV-infected cell models. Clodronate liposomes were used to deplete macrophages. We used HE staining and immunohistochemistry to determine inflammatory damage and virus replication. We detected the expression levels of inflammatory factors and IFN-ß through qPCR and ELISA. JC-1 kit was used for detecting the cell mitochondrial Membrane potential (MMP). ROS, SOD, and MDA kits were used for detecting intracellular oxidative stress damage. Metabolites of TCA in lung tissue and serum of mice were detected by GC-MS. Pharmacodynamic studies have shown that intervention with LUT-7G can alleviate lung tissue damage caused by RSV infection, inhibit RSV replication, and downregulate TNF-α, IL-1ß, and IL-6 mRNA expression. LUT-7G upregulated the IFN-ß content and the expression of IFN-ß, ISG15, and OAS1 mRNA. In vitro, LUT-7G inhibited RSV-induced cell death, reversed the RSV-induced decrease of MMP and decreased intracellular oxidative stress. Target metabonomics showed that RSV infection upregulated the levels of glycolysis and TCA metabolites in lung tissue and serum, while LUT-7G could improve the disorder of glucose metabolism. The results indicate that LUT-7G can promote the release of IFN-ß in the lung, alleviate inflammatory damage, and inhibit RSV replication during RSV infection. These effects may be achieved by protecting the mitochondrial function of alveolar macrophages and correcting the disorder of glucose metabolism.

Single-cell immune profiling reveals markers of emergency myelopoiesis that distinguish severe from mild respiratory syncytial virus disease in infants.

Whereas most infants infected with respiratory syncytial virus (RSV) show no or only mild symptoms, an estimated 3 million children under five are hospitalized annually due to RSV disease. This study aimed to investigate biological mechanisms and associated biomarkers underlying RSV disease heterogeneity in young infants, enabling the potential to objectively categorize RSV-infected infants according to their medical needs. Immunophenotypic and functional profiling demonstrated the emergence of immature and progenitor-like neutrophils, proliferative monocytes (HLA-DRLow , Ki67+), impaired antigen-presenting function, downregulation of T cell response and low abundance of HLA-DRLow B cells in severe RSV disease. HLA-DRLow monocytes were found as a hallmark of RSV-infected infants requiring hospitalization. Complementary transcriptomics identified genes associated with disease severity and pointed to the emergency myelopoiesis response. These results shed new light on mechanisms underlying the pathogenesis and development of severe RSV disease and identified potential new candidate biomarkers for patient stratification.

Histone acetylation regulates ORMDL3 expression-mediated NLRP3 inflammasome overexpression during RSV-allergic exacerbation mice.

Whether respiratory syncytial virus (RSV) infection in early life may induce orosomucoid 1-like protein 3 (ORMDL3) and lead to NOD-like receptor protein 3 (NLRP3) inflammasome overexpression in asthma, which could be alleviated by the inhibition of HAT p300. First, we explored the relationship between RSV, ORMDL3, and recurrent wheezing in the future through clinical data of infants with RSV-induced bronchiolitis. Then, we used bronchial epithelium transformed with Ad12-SV40 2B (BEAS-2B) and an asthmatic mouse model of repeated RSV infection and OVA sensitization and challenge (rRSV + OVA) in early life to assess the effects of ORMDL3 on NLRP3 inflammasome and that of histone acetylation on ORMDL3 regulation. ORMDL3 overexpression is the independent risk factor of recurrent wheezing in RSV-bronchiolitis follow-up. In BEAS-2B, ORMDL3-induced NLRP3 inflammasome expression. BEAS-2B infected by RSV resulted in overexpression of ORMDL3 and NLRP3 inflammasome and histone hyperacetylation, while ORMDL3-small interfering RNA and C646 interfered could decrease NLRP3 inflammasome. ORMDL3 overexpression in mouse lung increased NLRP3 inflammasome. The expression of ORMDL3 and NLRP3 inflammasome significantly increased, with histone hyperacetylation in the lung in rRSV + OVA mice. p300 and acetylH3 bound to ORMDL3 promoter. In C646 + rRSV + OVA mice, C646 alleviated lung inflammation and overexpression of ORMDL3 and NLRP3 inflammasome. RSV activated ORMDL3 overexpression through histone hyperacetylation and induced NLRP3 inflammasome expression.

TNFAIP3-interacting protein 1 polymorphisms and their association with symptomatic human respiratory syncytial virus infection and bronchiolitis in infants younger than one year from South Africa: A case-control study.

OBJECTIVES: This study analyzed the association of TNFAIP3-interacting protein 1 (TNIP1) polymorphisms with the symptomatic human respiratory syncytial virus (HRSV) infection and bronchiolitis in infants. METHODS: A case-control study was conducted involving 129 hospitalized infants with symptomatic HRSV infection (case group) and 161 healthy infants (control group) in South Africa (2016-2018). Six TNIP1 polymorphisms (rs869976, rs4958881, rs73272842, rs3792783, rs17728338, and rs999011) were genotyped. Genetic associations were evaluated using logistic regression adjusted by age and gender. RESULTS: Both rs73272842 G and rs999011 C alleles were associated with reduced odds for symptomatic HRSV infection (adjusted odd ratio [aOR] = 0.68 [95% confidence interval {CI} = 0.48-0.96] and aOR = 0.36 [95% CI = 0.19-0.68], respectively] and bronchiolitis (aOR = 0.71 [95% CI = 0.50-1.00] and aOR = 0.38 [95% CI = 0.22-0.66], respectively). The significance of these associations was validated using the BCa Bootstrap method (P <0.05). The haplotype GC (composed of rs73272842 and rs999011) was associated with reduced odds of symptomatic HRSV infection (aOR = 0.53 [95% CI = 0.37-0.77]) and bronchiolitis (aOR = 0.62 [95% CI = 0.46-0.84]), which were validated by the BCa Bootstrap method (P = 0.002 for both). CONCLUSION: TNIP1 rs73272842 G allele and rs999011 C allele were associated with reduced odds of symptomatic HRSV infection and the development of bronchiolitis in infants, suggesting that TNIP1 polymorphisms could impact susceptibility to HRSV illness.

Nasopharyngeal fungal subtypes of infant bronchiolitis and disease severity risk.

BACKGROUND: Bronchiolitis is a leading cause of infant hospitalization. Recent research suggests the heterogeneity within bronchiolitis and the relationship of airway viruses and bacteria with bronchiolitis severity. However, little is known about the pathobiological role of fungi. We aimed to identify bronchiolitis mycotypes by integrating fungus and virus data, and determine their association with bronchiolitis severity and biological characteristics. METHODS: In a multicentre prospective cohort study of 398 infants (age <1 year, male 59%) hospitalized for bronchiolitis, we applied clustering approaches to identify mycotypes by integrating nasopharyngeal fungus (detected in RNA-sequencing data) and virus data (respiratory syncytial virus [RSV], rhinovirus [RV]) at hospitalization. We examined their association with bronchiolitis severity-defined by positive pressure ventilation (PPV) use and biological characteristics by nasopharyngeal metatranscriptome and transcriptome data. RESULTS: In infants hospitalized for bronchiolitis, we identified four mycotypes: A) fungiM.restrictavirusRSV/RV, B) fungiM.restrictavirusRSV, C) fungiM.globosavirusRSV/RV, D) funginot-detectedvirusRSV/RV mycotypes. Compared to mycotype A infants (the largest subtype, n = 211), mycotype C infants (n = 85) had a significantly lower risk of PPV use (7% vs. 1%, adjOR, 0.21; 95% CI, 0.02-0.90; p = 0.033), while the risk of PPV use was not significantly different in mycotype B or D. In the metatranscriptome and transcriptome data, mycotype C had similar bacterial composition and microbial functions yet dysregulated pathways (e.g., Fc γ receptor-mediated phagocytosis pathway and chemokine signaling pathway; FDR <0.05). INTERPRETATION: In this multicentre cohort, fungus-virus clustering identified distinct mycotypes of infant bronchiolitis with differential severity risks and unique biological characteristics. FUNDING: This study was supported by the National Institutes of Health.

Nei-like DNA glycosylase 2 selectively antagonizes interferon-ß expression upon respiratory syncytial virus infection.

As part of the antiviral response, cells activate the expressions of type I interferons (IFNs) and proinflammatory mediators to control viral spreading. Viral infections can impact DNA integrity; however, how DNA damage repair coordinates antiviral response remains elusive. Here we report Nei-like DNA glycosylase 2 (NEIL2), a transcription-coupled DNA repair protein, actively recognizes the oxidative DNA substrates induced by respiratory syncytial virus (RSV) infection to set the threshold of IFN-ß expression. Our results show that NEIL2 antagonizes nuclear factor κB (NF-κB) acting on the IFN-ß promoter early after infection, thus limiting gene expression amplified by type I IFNs. Mice lacking Neil2 are far more susceptible to RSV-induced illness with an exuberant expression of proinflammatory genes and tissue damage, and the administration of NEIL2 protein into the airway corrected these defects. These results suggest a safeguarding function of NEIL2 in controlling IFN-ß levels against RSV infection. Due to the short- and long-term side effects of type I IFNs applied in antiviral therapy, NEIL2 may provide an alternative not only for ensuring genome fidelity but also for controlling immune responses.

Nasal airway microRNA profiling of infants with severe bronchiolitis and risk of childhood asthma: a multicentre prospective study.

BACKGROUND: Severe bronchiolitis (i.e. bronchiolitis requiring hospitalisation) during infancy is a major risk factor for childhood asthma. However, the exact mechanism linking these common conditions remains unclear. We examined the longitudinal relationship between nasal airway miRNAs during severe bronchiolitis and the risk of developing asthma. METHODS: In a 17-centre prospective cohort study of infants with severe bronchiolitis, we sequenced their nasal microRNA at hospitalisation. First, we identified differentially expressed microRNAs (DEmiRNAs) associated with the risk of developing asthma by age 6 years. Second, we characterised the DEmiRNAs based on their association with asthma-related clinical features, and expression level by tissue and cell types. Third, we conducted pathway and network analyses by integrating DEmiRNAs and their mRNA targets. Finally, we investigated the association of DEmiRNAs and nasal cytokines. RESULTS: In 575 infants (median age 3 months), we identified 23 DEmiRNAs associated with asthma development (e.g. hsa-miR-29a-3p; false discovery rate (FDR) <0.10), particularly in infants with respiratory syncytial virus infection (FDR for the interaction <0.05). These DEmiRNAs were associated with 16 asthma-related clinical features (FDR <0.05), e.g. infant eczema and corticosteroid use during hospitalisation. In addition, these DEmiRNAs were highly expressed in lung tissue and immune cells (e.g. T-helper cells, neutrophils). Third, DEmiRNAs were negatively correlated with their mRNA targets (e.g. hsa-miR-324-3p/IL13), which were enriched in asthma-related pathways (FDR <0.05), e.g. toll-like receptor, PI3K-Akt and FcɛR signalling pathways, and validated by cytokine data. CONCLUSION: In a multicentre cohort of infants with severe bronchiolitis, we identified nasal miRNAs during illness that were associated with major asthma-related clinical features, immune response, and risk of asthma development.

Modulation of autophagy and mTOR signaling pathway genes in respiratory epithelium by respiratory syncytial virus (RSV) in children suffering from acute lower respiratory tract infections.

The study was planned to carry out the molecular characterization of the respiratory syncytial virus (RSV) circulating strains and to elucidate the gene expression of autophagy and mammalian target of rapamycin (mTOR) signaling pathways in children with acute lower respiratory tract infection (ALRTI). Nasopharyngeal aspirate (NPA) samples (n = 145) from children suffering from ALRTI were subjected to the detection of RSV. Of them, 31 RSV positive strains were subjected for sequencing. Semi-quantitative gene expression analysis for mTOR signaling and autophagy pathway genes was performed in respiratory tract epithelial cells using 25 RSV positive cases, and 10 age and sex matched healthy control subjects. Five representative genes were selected for each pathway and subjected to SYBR green real-time polymerase chain reaction. RSV was positive in 69 (47.6%) samples and the representative (n = 31) RSV strains belonged to RSV-A. Thirty-one strains of RSV-A on phylogenetic analysis clustered with the novel ON1 genotype having 72 bp nucleotide duplicationby targeting the ecto-domain portion of the G gene. Further, the stains belonged to lineage 1 (51.6%), followed by lineage 3 (29%) and lineage 2 (19.4%). Autophagy gene expression analysis revealed significant upregulation in NPC1 and ATG3 autophagy genes. mTOR, AKT1, and TSC1 genes of the mTOR pathway were significantly downregulated in RSV positive patients. Thus, RSV infection inducing autophagy pathway genes (NPC1 and ATG3) and suppressing mTOR signaling pathway genes (AKT1, mTOR, and TSC1) to possibly evade the host immune system through dysregulating these pathways for its way of survival within the host.

Impact of the COVID-19 pandemic on the prevalence of influenza A and respiratory syncytial viruses elucidated by wastewater-based epidemiology.

Since the COVID-19 pandemic, a decrease in the prevalence of Influenza A virus (IAV) and respiratory syncytial virus (RSV) has been suggested by clinical surveillance. However, there may be potential biases in obtaining an accurate overview of infectious diseases in a community. To elucidate the impact of the COVID-19 on the prevalence of IAV and RSV, we quantified IAV and RSV RNA in wastewater collected from three wastewater treatment plants (WWTPs) in Sapporo, Japan, between October 2018 and January 2023, using highly sensitive EPISENS™ method. From October 2018 to April 2020, the IAV M gene concentrations were positively correlated with the confirmed cases in the corresponding area (Spearman's r = 0.61). Subtype-specific HA genes of IAV were also detected, and their concentrations showed trends that were consistent with clinically reported cases. RSV A and B serotypes were also detected in wastewater, and their concentrations were positively correlated with the confirmed clinical cases (Spearman's r = 0.36-0.52). The detection ratios of IAV and RSV in wastewater decreased from 66.7 % (22/33) and 42.4 % (14/33) to 4.56 % (12/263) and 32.7 % (86/263), respectively in the city after the COVID-19 prevalence. The present study demonstrates the potential usefulness of wastewater-based epidemiology combined with the preservation of wastewater (wastewater banking) as a tool for better management of respiratory viral diseases.

A human antibody potently neutralizes RSV by targeting the conserved hydrophobic region of prefusion F.

Respiratory syncytial virus (RSV) continues to pose serious threats to pediatric populations due to the lack of a vaccine and effective antiviral drugs. RSV fusion (F) glycoprotein mediates viral-host membrane fusion and is a key target for neutralizing antibodies. We generated 23 full-human monoclonal antibodies (hmAbs) against prefusion F protein (pre-F) from a healthy adult with natural RSV infection by single B cell cloning technique. A highly potent RSV-neutralizing hmAb, named as 25-20, is selected, which targets a new site Ø-specific epitope. Site-directed mutagenesis and structural modelling analysis demonstrated that 25-20 mainly targets a highly conserved hydrophobic region located at the a4 helix and a1 helix of pre-F, indicating a site of vulnerability for drug and vaccine design. It is worth noting that 25-20 uses an unreported inferred germline (iGL) that binds very poorly to pre-F, thus high levels of somatic mutations are needed to gain high binding affinity with pre-F. Our observation helps to understand the evolution of RSV antibody during natural infection. Furthermore, by in silico prediction and experimental verification, we optimized 25-20 with KD values as low as picomolar range. Therefore, the optimized 25-20 represents an excellent candidate for passive protection against RSV infection.

Genetic characterization of bovine respiratory syncytial viruses in Japan between 2017 and 2019.

Bovine respiratory syncytial virus (BRSV) strains that were detected in Kagoshima prefecture and isolated in Hokkaido between 2017 and 2019, together with a BRSV vaccine strain, were subjected to full-genome sequencing. The BRSV strains identified in Japan were found to be genetically close to each other but distant from the vaccine strains. The deduced amino acids at positions 206 and 208 of the glycoprotein (G protein), which form one of the major epitopes of the recent Japanese BRSV strains, were different from those of the vaccine strains. Therefore, the recent Japanese BRSV strains might be antigenically different from the BRSV vaccine strains.

Early origins of respiratory disease.

Chronic respiratory morbidity is unfortunately common in childhood, particularly in those born very prematurely or with congenital anomalies affecting pulmonary development and those with sickle cell disease. Our research group, therefore, has focused on the early origins of chronic respiratory disease. This has included assessing antenatal diagnostic techniques and potentially therapeutic interventions in infants with congenital diaphragmatic hernia. Undertaking physiological studies, we have increased the understanding of the premature baby's response to resuscitation and evaluated interventions in the delivery suite. Mechanical ventilation modes have been optimised and randomised controlled trials (RCTs) with short- and long-term outcomes undertaken. Our studies highlighted respiratory syncytial virus lower respiratory tract infections (LRTIs) and other respiratory viral LRTIs had an adverse impact on respiratory outcomes of prematurely born infants, who we demonstrated have a functional and genetic predisposition to respiratory viral LRTIs. We have described the long-term respiratory outcomes for children with sickle cell disease and importantly identified influencing factors. In conclusion, it is essential to undertake long term follow up of infants at high risk of chronic respiratory morbidity if effective preventative strategies are to be developed.