Acute RSV Research Articles

Assessing the patient experience of respiratory syncytial virus infection: development of a patient-reported outcome measure

BackgroundRespiratory syncytial virus (RSV) causes significant morbidity and mortality in older adults. Despite a number of RSV vaccine candidates in clinical trials, there are no existing disease-specific, self-reported measures that assess the symptoms and severity of RSV infection from the perspective of adult patients with acute RSV. The objective of this study was to describe the initial conceptualization and development of the RSV Infection, Intensity and Impact Questionnaire (RSV-iiiQ), a new patient-reported outcome measure.MethodsA targeted review of the literature identified relevant existing measures, symptoms, and impacts of RSV. A draft version of the RSV-iiiQ was developed based on the Influenza Intensity and Impact Questionnaire (Flu-iiQ) with expert input. Qualitative interviews (N = 20) were conducted with participants to optimize the RSV-iiiQ conceptual model and confirm the content validity of the RSV-iiiQ. Interviews included concept elicitation and a cognitive debriefing assessment. A draft conceptual framework was developed, and the electronic clinical outcome assessment was piloted. All steps of instrument development followed Food and Drug Administration guidance for patient-reported outcomes.ResultsIn-depth concept elicitation interviews followed by cognitive debriefings demonstrated that the content of the items was comprehensive, covered the breadth of RSV symptoms and impacts, and was relevant to the experiences of individuals with RSV. Both the paper and electronic versions of the RSV-iiiQ were easily completed. Minor refinements were made to some items based on participant feedback, and the draft conceptual framework was refined.ConclusionsThe RSV-iiiQ was developed for use in clinical trials to measure the symptom intensity and impact of acute RSV infection from the perspective of adult patients. The tool was developed in accordance with current regulatory guidance and is useful to support patient-focused drug development.

An atlas of the blood virome in healthy individuals

Emerging evidence indicates that gut virome plays a role in human health and disease, however, much less is known about the viral communities in blood. Here we conducted a direct metatranscriptomic sequencing of virus-like-particles in blood from 1200 healthy individuals, without prior amplification to avoid potential amplification bias and with a strictly bioinformatic and manual check for candidate viral reads to reduce false-positive matches. We identified 55 different viruses from 36 viral families, including 24 human DNA, RNA and retroviruses in 70% of the studied pools. The study showed that anelloviruses are widely distributed and dominate the blood virome in healthy individuals. Human herpesviruses and pegivirus-1 are commonly prevalent in asymptomatic humans. We identified the prevalence of RNA viruses often causing acute infection, like HEV, HPIV, RSV and HCoV-HKU1, revealing of a transmissible risk of asymptomatic infection. Several viruses possible related to transfusion safety were identified, including human Merkel cell polyomavirus, papillomavirus, parvovirus B19 and herpesvirus 8 in addition to HBV. In addition, phages in Caudovirales and Microviridae, were commonly found in pools of samples with a very low abundance; a few sequences for invertebrate, plant and giant viruses were found in some of individuals; however, the remaining 31 viruses mostly reflect extensive contamination from commercial reagents and the work environments. In conclusion, this study is the first comprehensive investigation of blood virome in healthy individuals by metatranscriptomic sequencing of VLP in China. Further investigation of potential false positives representing a major challenge for the identification of novel viruses in mNGS, will offer a systemic idea and means to reveal true viral infections of human.

The immunogenicity and safety of respiratory syncytial virus vaccines in development: A systematic review.

BackgroundRespiratory syncytial virus (RSV) is a leading cause of acute lower respiratory infection globally. There are vaccine candidates in development, but a systematic review on immunogenicity and safety of vaccine is lacking.MethodsThis systematic review of RSV vaccine clinical trials was undertaken using four databases. Searches were conducted using both controlled vocabulary terms such as “Respiratory Syncytial Virus, Human,” “Respiratory Syncytial Virus Infections,” “Respiratory Syncytial Virus Vaccines,” “Immunization,” “Immunization Programs” and “Vaccines” and corresponding text word terms. The included studies were limited to clinical trials published from January 2000 to 31 December 2020. RSV infection case was defined as RSV‐associated medically attended acute respiratory illness (MAARI) or RSV infection by serologically confirmed test (Western blot) during the RSV surveillance period. We calculated the relative risk of each vaccine trial with RSV infection case.ResultsOf 6306 publications, 38 were included and data were extracted covering four major types of RSV vaccine candidates, these being live‐attenuated/chimeric (n = 14), recombinant‐vector (n = 6), subunit (n = 12) and nanoparticle vaccines (n = 6). For RSV infection cases, nine trials were involved and none of them showed a vaccine‐related increased MAARI during RSV surveillance season.ConclusionLID ∆M2‐2, MEDI M2‐2, RSVcps2 and LID/∆M2‐2 /1030s (live‐attenuated) were considered the most promising vaccine candidates in infant and children. In the elderly, a nanoparticle F vaccine candidate and Ad26.RSV.preF were considered as two potential effective vaccines. A promising maternal vaccine candidate is still lacking.

Estimating the Economic Impact of Respiratory Syncytial Virus and Other Acute Respiratory Infections Among Infants Receiving Care at a Referral Hospital in Malawi.

Respiratory syncytial virus (RSV) is a leading cause of respiratory illness among infants globally, yet economic burden data are scant, especially in low-income countries. We collected data from 426 infants enrolled in the Queen Elizabeth Central Hospital respiratory disease surveillance platform to estimate the household and health system costs of managing RSV and other respiratory pathogens in Malawian infants. Total household cost per illness episode, including direct and indirect costs and lost income, was reported by parents/guardians at the initial visit and 6 weeks post discharge. The total cost to the health system was based on patient charts and hospital expenditures. All-cause acute respiratory infections (ARIs) and RSV costs for inpatient and outpatients are presented separately. All costs are in the 2018 US Dollar. The mean costs per RSV episode were $62.26 (95% confidence interval [CI]: $50.87-$73.66) and $12.51 (95% CI: $8.24-$16.79) for inpatient and outpatient cases, respectively. The mean cost per episode for all-cause ARIs was slightly higher among inpatients at $69.93 (95% CI: $63.06-$76.81) but slightly lower for outpatients at $10.17 (95% CI: $8.78-$11.57). Household costs accounted for roughly 20% of the total cost per episode. For the lowest-income families, household cost per inpatient RSV episode was about 32% of total monthly household income. Among infants receiving care at a referral hospital in Malawi, the cost per episode in which RSV was detected is comparable to that of other episodes of respiratory illnesses where RSV was not detected. Estimates generated in this study can be used to evaluate the economic and financial impact of RSV and acute respiratory illness preventive interventions in Malawi.

Cellular Mechanisms Triggered by the Cotreatment of Resveratrol and Doxorubicin in Breast Cancer: A Translational In Vitro-In Silico Model.

Doxorubicin (Doxo) is the most effective chemotherapeutic agent for the treatment of breast cancer. However, resistance to Doxo is common. Adjuvant compounds capable of modulating mechanisms involved in Doxo resistance may potentiate the effectiveness of the drug. Resveratrol (Rsv) has been tested as an adjuvant in mammary malignancies. However, the cellular and molecular mechanisms underlying the effects of cotreatment with Doxo and Rsv in breast cancer are poorly understood. Here, we combined in vitro and in silico analysis to characterize these mechanisms. In vitro, we employed a clinically relevant experimental design consisting of acute (24 h) treatment followed by 15 days of analysis. Acute Rsv potentiated the long-lasting effect of Doxo through the induction of apoptosis and senescence. Cells that survived to the cotreatment triggered high levels of autophagy. Autophagy inhibition during its peak of activation but not concomitant with Doxo+Rsv increased the long-term toxicity of the cotreatment. To uncover key proteins potentially associated with in vitro effects, an in silico multistep strategy was implemented. Chemical-protein networks were predicted based on constitutive gene expression of MCF7 cells and interatomic data from breast cancer. Topological analysis, KM survival analysis, and a quantitative model based on the connectivity between apoptosis, senescence, and autophagy were performed. We found seven putative genes predicted to be modulated by Rsv in the context of Doxo treatment: CCND1, CDH1, ESR1, HSP90AA1, MAPK3, PTPN11, and RPS6KB1. Six out of these seven genes have been experimentally proven to be modulated by Rsv in cancer cells, with 4 of the 6 genes in MCF7 cells. In conclusion, acute Rsv potentiated the long-term toxicity of Doxo in breast cancer potentially through the modulation of genes and mechanisms involved in Doxo resistance. Rational autophagy inhibition potentiated the effects of Rsv+Doxo, a strategy that should be further tested in animal models.

Cold Weather Viruses.

1. Asif Noor, MD* 2. Theresa Fiorito, MD* 3. Leonard R. Krilov, MD*,† 1. *Department of Pediatrics, Children's Medical Center, NYU Winthrop Hospital, Mineola, NY 2. †Department of Pediatrics, State University of New York, Stony Brook School of Medicine, Stony Brook, NY * Abbreviations: AAP: : American Academy of Pediatrics Adv: : adenovirus CDC: : Centers for Disease Control and Prevention FDA: : Food and Drug Administration hMPV: : human metapneumovirus PCR: : polymerase chain reaction PIV: : parainfluenza virus RSV: : respiratory syncytial virus RV: : rhinovirus Clinicians must learn to identify viral infections in children during the winter months and must practice caution with the use of unnecessary medications in such cases. Recognition of the clinical pattern of viral infection (eg, bronchiolitis) in conjunction with judicious use of viral tests (either office-based immunoassays or newer molecular tests) may assist in epidemiological monitoring, cohorting patients in the hospital, withholding unnecessary therapies, and providing a definitive diagnosis. After completing this article, readers should be able to: 1. Review the epidemiological aspects and clinical signs and symptoms of common cold weather viruses. 2. Recognize situations in which viral testing is indicated. 3. Recognize situations in which treatment is indicated. In early November you are evaluating a 9-month-old boy born at 33 weeks of gestation. The infant presents with 2 days of fevers (101°F–102°F [38.3°C–38.8°C]), copious rhinorrhea, and 1 day of coughing with difficulty breathing. He is otherwise feeding well and has had adequate urination. His 4-year-older sister has an upper respiratory tract infection. On physical examination, the infant has a respiratory rate of 45 breaths/min without chest wall retractions. On auscultation there is good air entry with scattered rhonchi bilaterally. What is the most appropriate next step in management? 1. Obtain respiratory syncytial virus (RSV) and influenza antigen testing. 2. Obtain a chest radiograph to look for focal infiltrate. 3. Provide supportive care with nasal …

Is Palivizumab Therapy Effective for Acute RSV Bronchiolitis?

Is Palivizumab Therapy Effective for Acute RSV Bronchiolitis?

Monoclonal Antibody Treatment of RSV Bronchiolitis in Young Infants: A Randomized Trial.

Monoclonal antibody to respiratory syncytial virus (RSV; palivizumab) is recommend for prophylaxis of high-risk infants during bronchiolitis seasons but not for RSV bronchiolitis treatment. Our aim was to determine if palivizumab would be helpful in young infants with acute RSV bronchiolitis. Eligible infants ≤3 months old presenting to the pediatric emergency service with RSV-positive bronchiolitis requiring inpatient admission underwent double-blind random assignment to single-dose intravenous palivizumab (15 mg/kg) or placebo. The primary efficacy outcome was the need for inpatient readmission in the 3 weeks after discharge. Secondary outcomes were time to readiness for hospital discharge, need for PICU on the initial admission, and need for revisit not requiring readmission for the same illness during 3-week follow-up. A total of 420 infants (median age 49 days) diagnosed with RSV bronchiolitis were randomly assigned; 417 received treatment, and 413 completed follow-up. Readmission during follow-up was needed for 23 (11%) patients on palivizumab and 19 (9.3%) patients in the placebo group (difference 1.8%; 95% confidence interval -4.4% to 7.7%; P = .51). Geometric mean time to readiness for discharge was 29.5 hours for the palivizumab group and 30.2 hours for the placebo group (ratio 0.98; 95% confidence interval 0.81 to 1.20). No safety issues were reported. Intravenous palivizumab did not appear to help or harm young infants with acute RSV-positive bronchiolitis.

The human immune response to RSV includes a loop between the tumor suppressor p53 and expression of APOBEC3 genes

BackgroundRespiratory syncytial virus (RSV) infects nearly all children by theirsecond year of life with re‐infections occurring throughout adolescence andadulthood. RSV infection typicallyresults in mild host symptoms. However, susceptible individuals can develop severe lower respiratory tract infectionsand bronchiolitis, sometimes leading to hospitalization or death. Recently we established that in addition toits protective role against cancer development, the tumor suppressor p53 alsocontributes to host immune responses regulating the expression of several genesincluding the APOBEC3 family of DNA cytidine deaminases (A3), consideredsentinels in innate immune response against viral infections.ObjectiveUsinghuman lung cancer cells, we tested the role of p53 in response to RSV infectionand its replication through the regulation of the A3 gene family as well asother components of the immune response.MethodsA549 and H1299 cells were infected with RSV (Strain A2). Cells were thenharvested 72–120 hours post‐infection and qPCR and Nanostring arrays? were usedto evaluate mRNA expression of RSV‐g, P53, A3s and other immune targets. Expression of RSV was assessed? by ConfocalMicroscopy and cytofluorometry while Annexin V/PI assay was used to evaluateapoptosis.ResultsIn response to acute and chronic RSV infection in human lung cancer cells, p53 was activated and had an impact on RSV replication, which involves theexpression in a p53 dependent manner of several members of the A3 gene familyas well as other innate immune genes. APOBEC3G (A3G) was highly induced in a dose‐ and time‐dependent mannerafter RSV only in lung cancer cells harboring WT p53. Accordingly, overexpression of A3G in lungcancer cells reduced RSV replication. Furthermore, a Nanotstring transcriptome analysis (immune code set) after RSV infectionrevealed a strong p53 dependent regulation of immune response genes, includingseveral components of the innate immune antiviral response. In addition, RSV infection induced p53phosphorylation at serine 15 and triggered p53‐dependent apoptosis in p53 functional cells while p53 deficiency correlated with increased viralreplication and increased syncytia phenotype.ConclusionsOverall, our findings establish that the “guardian of the genome” role ascribed to p53 also extends to a unique component of the immune system – the A3 genes – revealing novel components in the antiviralimmune response against RSV infection.Support or Funding InformationSupported by NIEHS Division of Intramural Research Program.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Conditioned medium from persistently RSV-infected macrophages alters transcriptional profile and inflammatory response of non-infected macrophages

Cells susceptible to persistent viral infections undergo important changes in their biological functions as a consequence of the expression of viral gene products that are capable of altering the gene expression profile of the host cell. Previously, we reported that persistence of the RSV genome in a mouse macrophage cell line induces important alterations in cell homeostasis, including constitutive expression of IFN-β and other pro-inflammatory cytokines. Here, we postulated that changes in the homeostasis of non-infected macrophages could be induced by soluble factors secreted by persistently RSV- infected macrophages. To test this hypothesis, non-infected mouse macrophages were treated with conditioned medium (CM) collected from cultures of persistently RSV-infected macrophages. Total RNA was extracted and a microarray-based gene expression analysis was performed. Non-infected macrophages, treated under similar conditions with CM obtained from cultures of non-infected macrophages, were used as a control to establish differential gene expression between the two conditions. Results showed that CM from the persistently RSV-infected cultures altered expression of a total of 95 genes in non-infected macrophages, resulting in an antiviral gene-transcription profile along with inhibition of the inflammatory response, since some inflammatory genes were down-regulated, including Nlrp3 and Il-1 β, both related to the inflammasome pathway. However, down-regulation of Nlrp3 and Il-1 β was reversible upon acute RSV infection. Additionally, we observed that the inflammatory response, evaluated by secreted IL-1 β, a final product of the inflammasome activity, was enhanced during acute RSV infection in macrophages treated with CM from persistently RSV-infected cultures, compared to that in macrophages treated with the control CM. This suggests that soluble factors secreted during RSV persistence may induce an exacerbated inflammatory response in non-infected cells.

Thymus activity measured by T-cell receptor excision circles in patients with different severities of respiratory syncytial virus infection

BackgroundRespiratory syncytial virus (RSV) infection is an important cause of hospitalization in previously healthy infants. Immunological mechanisms predisposing infants to severe disease are poorly understood. Early biomarkers for disease severity may assist clinical decisions. We investigated T-cell receptor excision circles (TREC), episomal DNA made during thymic T-cell receptor rearrangement, and a marker for thymus activity, both during disease and in neonatal screening cards as a risk factor for RSV disease severity.MethodsOne hundred thirteen patients hospitalized with RSV infection <12 months of age, grouped by disease severity, were available for this investigation, in which we conducted both a prospective and a case-control study. The prospective study included 47 RSV positive infants (mild n = 13, moderate n = 10, severe n = 24). TREC counts were determined by PCR of DNA extracted from EDTA-blood collected on hospitalization, and corrected for lymphocytes using ANCOVA. The case-control study included 85 newborns who later in infancy became RSV positive (mild n = 32, moderate n = 24, severe n = 29) and 47 newborns who never developed RSV disease as healthy controls included from health centres in the same catchment area. TRECs were measured using DNA extracted from dry blood spots from stored neonatal screening cards, followed by PCR. Student’s T-test compared patients with controls, ANOVA compared disease severity groups.ResultsDuring RSV infection patients in the severe disease group had significantly lower (p = 0.017) TREC/200 μL blood compared to the other two disease groups, after correction for lymphocyte count. Newborn TREC levels, were significantly higher in RSV patients compared to controls (p < 0.0001). No significant differences in TREC copies at birth were found between disease severities.ConclusionDuring acute RSV infection a lower number of TREC is found in the severe disease group. TREC has potential as an immunological marker for severe RSV infection. Higher neonatal TREC counts indicate that infants later presenting with severe RSV do not have reduced thymic activity at birth and probably no congenital T-cell defect.

Down syndrome as risk factor for respiratory syncytial virus hospitalization: A prospective multicenter epidemiological study.

BackgroundRespiratory syncytial virus (RSV) infection in childhood, particularly in premature infants, is associated with significant morbidity and mortality.ObjectivesTo compare the hospitalization rates due to RSV infection and severity of disease between infants with and without Down syndrome (DS) born at term and without other associated risk factors for severe RSV infection.Patients/MethodsIn a prospective multicentre epidemiological study, 93 infants were included in the DS cohort and 68 matched by sex and data of birth (±1 week) and were followed up to 1 year of age and during a complete RSV season.ResultsThe hospitalization rate for all acute respiratory infection was significantly higher in the DS cohort than in the non‐DS cohort (44.1% vs 7.7%, P<.0001). Hospitalizations due to RSV were significantly more frequent in the DH cohort than in the non‐DS cohort (9.7% vs 1.5%, P=.03). RSV prophylaxis was recorded in 33 (35.5%) infants with DS. The rate of hospitalization according to presence or absence of RSV immunoprophylaxis was 3.0% vs 15%, respectively.ConclusionsInfants with DS showed a higher rate of hospitalization due to acute lower respiratory tract infection and RSV infection compared to non‐DS infants. Including DS infants in recommendations for immunoprophylaxis of RSV disease should be considered.

Respiratory Syncytial Virus: Infection, Detection, and New Options for Prevention and Treatment.

Respiratory syncytial virus (RSV) infection is a significant cause of hospitalization of children in North America and one of the leading causes of death of infants less than 1 year of age worldwide, second only to malaria. Despite its global impact on human health, there are relatively few therapeutic options available to prevent or treat RSV infection. Paradoxically, there is a very large volume of information that is constantly being refined on RSV replication, the mechanisms of RSV-induced pathology, and community transmission. Compounding the burden of acute RSV infections is the exacerbation of preexisting chronic airway diseases and the chronic sequelae of RSV infection. A mechanistic link is even starting to emerge between asthma and those who suffer severe RSV infection early in childhood. In this article, we discuss developments in the understanding of RSV replication, pathogenesis, diagnostics, and therapeutics. We attempt to reconcile the large body of information on RSV and why after many clinical trials there is still no efficacious RSV vaccine and few therapeutics.

Safety and Pharmacokinetics of the Respiratory Syncytial Virus Polymerase Inhibitor, ALS-8176, in Otherwise Healthy Infants Hospitalized with Acute RSV Infection

Safety and Pharmacokinetics of the Respiratory Syncytial Virus Polymerase Inhibitor, ALS-8176, in Otherwise Healthy Infants Hospitalized with Acute RSV Infection

Memory CD8 T cells in RSV infection: friend or foe?

Abstract Respiratory syncytial virus (RSV) is the leading cause of severe respiratory tract infection in infants and young children. CD8 T cells play a critical role in mediating viral clearance following an acute RSV infection. However the role of memory CD8 T cells in providing protection against RSV remains understudied. To generate high magnitude CD8 T cell memory in the absence of CD4 T cell memory and antibodies, we immunized naïve mice with dendritic cells pulsed with an RSV-derived peptide followed by a boost with a recombinant Listeria monocytogenes expressing the same RSV-derived epitope. Memory CD8 T cells significantly reduced viral titers following RSV challenge, but did so at the expense of increased airway dysfunction, weight loss, and mortality compared to controls. Importantly, the severe immunopathology and mortality observed was specific to the context of an RSV infection, as prime-boosted mice challenged with a recombinant influenza virus expressing the same RSV-derived epitope did not exhibit enhanced disease. The induction of a pro-inflammatory cytokine storm mediated by TNF-α and IFN-γ was observed in the serum of prime-boosted mice following RSV challenge. Additionally, RSV-specific memory CD8 T cells produced large amounts of IFN-γ locally within the lung, and adoptive transfer of wild-type but not IFN-γ-deficient memory CD8 T cells resulted in enhanced airway dysfunction and weight loss. Our results indicate that memory CD8 T cells are able to mediate protection against RSV infection. However, memory CD8 T cells acting alone in the absence of antibodies and memory CD4 T cells induce significant immunopathology and mortality through the induction of a systemic pro-inflammatory cytokine storm and local IFN-γ production.

The increased type-1 and type-2 chemokine levels in children with acute RSV infection alter the development of adaptive immune responses.

Severe RSV infections and frequent recurrence could be related to the altered polarization of type-2/type-1 T cells. This increases the importance of determining distinctive chemokines and chemokine receptor profiles on memory T cells. We analyzed systemic adaptive T cell response in the acute (n = 17) and convalescent phase (n = 7) of RSV-infected children, in the acute (n = 11) and convalescent phase (n = 6) of children with other viral respiratory infections (adenovirus and influenza virus), and in healthy children (n = 18). Expression of CCR4 and CXCR3 on effector-memory (TEM) and central-memory (TCM) T cells was compared between tested groups. Serum concentrations of specific chemokines were determined. High CXCL10 levels were detected in acutely infected children regardless of virus pathogen, whereas increased CCL17 production was RSV-specific. Higher percentages of CCR4+ CD4 TEM cells in acute RSV infection were accompanied with higher percentages of CXCR3+ CD8 TEM cells, whereas the development of long-lived memory CXCR3+ CD4 and CD8 TCM cells seems to be compromised, as only children with other viral infections had higher percentages in the convalescent phase. Presence of type-2 and type-1 adaptive antiviral immune response, together with insufficient development of long-lived type-1 T cell memory, could play an important role in RSV pathogenesis and reinfection.

Determining the Breadth of the Respiratory Syncytial Virus-Specific T Cell Response

Respiratory syncytial virus (RSV) is the most common cause of viral lower respiratory tract infections in infants and children under the age of 5. Studies examining RSV infection in susceptible BALB/c mice indicate that both CD4 and CD8 T cells not only contribute to viral clearance but also facilitate RSV-induced disease. However, efforts to understand the mechanisms by which RSV-specific T cells mediate disease following acute RSV infection have been hampered by the lack of defined RSV-specific T cell epitopes. Using an overlapping peptide library spanning each of the RSV-derived proteins, intracellular cytokine staining for gamma interferon was utilized to identify novel RSV-specific CD4 and CD8 T cell epitopes. Five novel CD8 T cell epitopes were revealed within the RSV fusion (F) protein and glycoprotein (G). In addition, five previously unidentified CD4 T cell epitopes were discovered, including epitopes in the phosphoprotein (P), polymerase protein (L), M2-1 protein, and nucleoprotein (N). Though the initial CD4 T cell epitopes were 15 amino acids in length, synthesis of longer peptides increased the frequency of responding CD4 T cells. Our results indicate that CD4 T cell epitopes that are 17 amino acids in length result in more optimal CD4 T cell stimulation than the commonly used 15-mer peptides. Respiratory syncytial virus (RSV) is the leading cause of hospitalization for lower respiratory tract infection in children. T cells play a critical role in clearing an acute RSV infection, as well as contributing to RSV-induced disease. Here we examined the breadth of the RSV-specific T cell response, using for the first time an overlapping peptide library spanning the entire viral genome. We identified 5 new CD4 and 5 new CD8 T cell epitopes, including a CD8 T cell epitope within the G protein that was previously believed not to elicit a CD8 T cell response. Importantly, we also demonstrated that the use of longer, 17-mer peptides elicits a higher frequency of responding CD4 T cells than the more commonly used 15-mer peptides. Our results demonstrate the breadth of the CD4 and CD8 T cell response to RSV and demonstrate the importance of using longer peptides when stimulating CD4 T cell responses.

Critical role of PD-L2 in limiting pulmonary immunopathology during RSV infection (P6182)

Abstract Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract-associated hospitalizations in children under the age of 2. Acute RSV infection induces both Th1- and Th2-associated responses, with elevated airway hyperactivity being highly correlated with increased Th2-associated responses. However, the mechanism for induction of Th1 vs. Th2-associated responses following RSV infection is currently unknown. The inhibitory ligands PD-L1 and PD-L2 serve a critical role in the induction and regulation of Th1 and Th2-associated responses, respectively, during acute infections as well as asthma. Following acute RSV infection, lung epithelial cells upregulate PD-L1 within 24 hours post-infection (p.i.) with peak expression occurring at day 6 p.i.. Furthermore, both lung and mediastinal lymph node (MedLN) CD11c+ cDCs and pDCs upregulate PD-L1 expression early following RSV infection and retain increased PD-L1 expression throughout the course of infection. In contrast, PD-L2 expression is primarily restricted to CD11c+ cDCs. PD-L2 expression peaks at day 6 p.i. on both lung and MedLN CD11c+ cDCs, correlating with increased airway resistance following acute RSV infection. PD-L2-blockade early during RSV infection results in increased airway hyperactivity, whereas PD-L1-blockade exhibited no significant effect. These data suggest that PD-L2 plays a critical role in the regulation of RSV-induced immunopathology.

Respiratory syncytial virus infection increases regulated on activation normal T cell expressed and secreted and monocyte chemotactic protein 1 levels in serum of patients with asthma and in human monocyte cultures

BackgroundRespiratory syncytial virus (RSV) infection is associated to episodic exacerbations of asthma involving alveolar macrophages and chemokine production. ObjectiveThe aim of this study was to determine the circulating levels of monocyte chemotactic protein 1 (MCP-1), regulated on activation normal T cell expressed and secreted (RANTES), and substance P (SP) in patients with and without asthma with acute respiratory RSV infection and the chemokine profile in RSV- infected monocyte cultures from normal individuals and individuals with asthma. MethodsIn this regard, 31 adult patients with acute respiratory infection (15 patients with asthma) were studied. MCP-1, RANTES and SP were measured in serum and in supernatants from monocyte cultures by enzyme-linked immunosorbent assay (ELISA). ResultsIncreased levels of MCP-1 and RANTES were observed in serum from patients with asthma related to RSV infection. RSV-infected monocyte cultures from healthy individuals showed increased content of those chemokines, and monocyte cultures from patients with asthma showed increased expression of MCP-1. ConclusionThese data show that RSV infection induces increased circulating level of chemokines in patients with asthma, and this finding could be mediated in part by the interaction virus-monocyte.

Increased Nasal Interleukin-33 in the Infants with Acute Respiratory Syncytial Virus Bronchiolitis

목 적 : Interleukin (IL)-33은 IL-1 계열에 속하는 사이토카인으로 호흡기 점막의 선천 면역에 기여하며 Th2 면역반응을 유도하는 것으로 알려져 있다. 본 연구에서는 RSV감염에 의한 급성 세기관지염으로 입원하였던 소아들에서 IL-33이 기도 염증 반응의 기전에 관여하는지 알아보고자 하였다. 방 법: 출생 이후 처음으로 respiratory syncytial virus(RSV) 감염에 의한 급성 세기관지염으로 입원 치료하였던 38명의 24개월 미만 연령의 소아들을 대상으로 하였다. 아토피는 최소한 1개 이상의 혈청 내 알레르겐 특이 immunoglobulin E 항체를 가지고 있거나 알레르겐에 대한 피부 반응 검사에서 1 개 이상의 양성 반응을 보였던 경우로 정의하였고 입원 중 산소 포화도가 92% 이하인 상태가 있었거나 , 빈호흡이 있었거나, 천명의 지속 기간이 1주일 이상이었던 경우들 중 2가지 이상의 소견을 나타내었던 경우를 심한 호흡기 증상을 나타내었던 경우로 정의하였다. IL-33과 IL-33 수용체(sST2)는 입원 당시 채취한 비분비물에서 enzyme-linked immunosorbent assay 방법으로 측정하여 대조군과 비교하였으며 또한 소아들의 아토피 상태 및 증상의 심한 정도에 따른 차이가 있는지 조사하였다. 결 과 : 비분비물의 IL-33 측정치는 RSV 세기관지염 환자군에서 대조군에 비해 유의하게 증가되어 있었으나(P＜0.05), IL-33 수용체는 두 군간에 차이를 보이지 않았다. IL-33과 IL-33 수용체는 모두 소아들의 아토피나 증상의 심한 정도와는 관련성을 보이지 않았다. 결 론 : 본 연구의 결과는 RSV 감염에 의한 호흡기 염증반응의 기전에 IL-33이 중요하게 관여할 가능성을 시사하는 것으로 생각된다.