scholarly journals Differential Role for TLR3 in Respiratory Syncytial Virus-Induced Chemokine Expression

2005 ◽  
Vol 79 (6) ◽  
pp. 3350-3357 ◽  
Author(s):  
Brian D. Rudd ◽  
Ezra Burstein ◽  
Colin S. Duckett ◽  
Xiaoxia Li ◽  
Nicholas W. Lukacs
Keyword(s):  
Respiratory Syncytial Virus ◽  
Epithelial Cells ◽  
Viral Replication ◽  
Signaling Pathways ◽  
Rna Virus ◽  
Lung Fibroblasts ◽  
Dependent Manner ◽  
Chemokine Production ◽  
Young Infants ◽  
Syncytial Virus

ABSTRACT Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infection in young infants worldwide. Previous studies have reported that the induction of interleukin-8/CXCL8 and RANTES/CCL5 correlates with disease severity in humans. The production of these chemokines is elicited by viral replication and is NF-κB dependent. RSV, a negative-sense single-stranded RNA virus, requires full-length positive-sense RNA for synthesis of new viral RNA. The aim of our studies was to investigate whether active viral replication by RSV could evoke chemokine production through TLR3-mediated signaling pathways. In TLR3-transfected HEK 293 cells, live RSV preferentially activated chemokines in both a time- and dose-dependent manner compared to vector controls. RSV was also shown to upregulate TLR3 in human lung fibroblasts and epithelial cells (MRC-5 and A549). Targeting the expression of TLR3 with small interfering RNA decreased synthesis of IP-10/CXCL10 and CCL5 but did not significantly reduce levels of CXCL8. Blocking the expression of the adapter protein MyD88 established a role for MyD88 in CXCL8 production, whereas CCL5 synthesis was found to be MyD88 independent. Production of CCL5 by RSV was induced directly through TLR3 signaling pathways and did not require interferon (IFN) signaling through the IFN-α/β receptor. TLR3 did not affect viral replication, since equivalent viral loads were recovered from RSV-infected cells despite altered TLR3 expression. Taken together, our studies indicate that TLR3 mediates inflammatory cytokine and chemokine production in RSV-infected epithelial cells.

scholarly journals The Interferon Type I/III Response to Respiratory Syncytial Virus Infection in Airway Epithelial Cells Can Be Attenuated or Amplified by Antiviral Treatment

2015 ◽  
Vol 90 (4) ◽  
pp. 1705-1717 ◽  
Author(s):  
K. M. McCutcheon ◽  
R. Jordan ◽  
M. E. Mawhorter ◽  
S. L. Noton ◽  
J. G. Powers ◽  
...  
Keyword(s):  
Life Cycle ◽  
Respiratory Syncytial Virus ◽  
Epithelial Cells ◽  
Viral Replication ◽  
Airway Epithelial Cells ◽  
Therapeutic Interventions ◽  
Airway Epithelial ◽  
Antiviral Activities ◽  
Syncytial Virus ◽  
Interferon Responses

ABSTRACTHuman respiratory syncytial virus (RSV) is a single-stranded RNA virus that causes acute, and occasionally fatal, lower respiratory illness in young infants, the elderly, and immunocompromised patients. Therapeutic interventions able to cut short viral replication and quickly return the airways to normal function are needed. An understanding of antiviral activities and their effects on host defense mechanisms is important for the design of safe and effective therapy. We targeted functionally and temporally distinct steps within the viral life cycle using small-molecule RSV inhibitors and studied their antiviral activities and their effects on innate interferon responses of airway epithelial cellsin vitro. Antivirals acting upstream of RSV polymerase activity (i.e., compounds targeting the fusion protein or the nucleoprotein) reduced viral load immediately postinfection and partially attenuated interferon responses. In contrast, antivirals directed to the RSV polymerase demonstrated activity throughout the viral replication cycle and specifically modulated the RIG-I/mitochondrial antiviral signaling protein (MAVS)/TBK1/IRF3/interferon-stimulated gene (ISG) axis, causing either an upregulation or a downregulation of interferon responses, depending on the mechanism of polymerase inhibition. Notably, polymerase inhibition leading to the accumulation of abortive RNA products correlated with the amplification of interferon-stimulated genes to up to 10 times above normal infection levels. Understanding how antiviral activities and their modulation of innate immunity may affect recovery from RSV infection will help guide the development of safe and effective therapies.IMPORTANCERSV circulates seasonally, causing acute lower respiratory disease. Therapeutic interventions with efficacy throughout the viral replication cycle, rapid viral clearance, and prevention of potentially harmful inflammatory responses are desirable. Compounds targeting the RSV polymerase inhibited virus replication late in the viral life cycle and, depending on the functional domain targeted, either attenuated or amplified RIG-I and downstream interferon pathways in infected cells. These data will help guide the development of safe and effective therapies by providing new molecular evidence that the mechanism of inhibition by an antiviral compound can directly impact innate antiviral immune responses in the airway epithelium.

scholarly journals Optimization of the Codon Pair Usage of Human Respiratory Syncytial Virus Paradoxically Resulted in Reduced Viral Replication In Vivo and Reduced Immunogenicity

2019 ◽  
Vol 94 (2) ◽  
Author(s):  
Cyril Le Nouën ◽  
Cindy L. Luongo ◽  
Lijuan Yang ◽  
Steffen Mueller ◽  
Eckard Wimmer ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Viral Replication ◽  
Virus Replication ◽  
Neutralizing Antibodies ◽  
Rna Virus ◽  
Humoral Immune ◽  
Codon Pair ◽  
Syncytial Virus ◽  
Codon Pairs

ABSTRACT We subjected various open reading frames (ORFs) in the genome of respiratory syncytial virus (RSV) to codon pair optimization (CPO) by increasing the content of codon pairs that are overrepresented in the human genome without changing overall codon usage and amino acid sequences. CPO has the potential to increase the expression of the encoded protein(s). Four viruses were made: Max A (with CPO of NS1, NS2, N, P, M, and SH ORFs), Max B (with CPO of G and F), Max L (with CPO of L), and Max FLC (with CPO of all ORFs except M2-1 and M2-2). Because of the possibility of increased viral replication, each CPO virus was attenuated by the inclusion of a codon deletion mutation (Δ1313) and a missense mutation (I1314L) in the L polymerase. CPO had no effect on multicycle virus replication in vitro, temperature sensitivity, or specific infectivity. Max A and L, which in common had CPO of one or more ORFs of proteins of the polymerase complex, exhibited global increases in viral protein synthesis. Max B alone exhibited decreased protein synthesis, and it alone had reduced single-cycle virus replication in vitro. All CPO RSVs exhibited marginal reductions in replication in mice and hamsters. Surprisingly, the CPO RSVs induced lower levels of serum RSV-neutralizing antibodies in hamsters. This reduced immunogenicity might reflect reduced viral replication and possibly also the decrease in CpG and UpA dinucleotides as immune stimulators. Overall, our study describes paradoxical effects of CPO of an RNA virus on viral replication and the adaptive humoral immune response. IMPORTANCE Using computer algorithms and large-scale DNA synthesis, one or more ORFs of a microbial pathogen can be recoded by different strategies that involve the introduction of up to thousands of nucleotide changes without affecting amino acid coding. This approach has been used mostly to generate deoptimized viruses used as vaccine candidates. However, the effects of the converse approach of generating optimized viruses are still largely unknown. Here, various ORFs in the genome of respiratory syncytial virus (RSV) were codon pair optimized (CPO) by increasing the content of codon pairs that are overrepresented in the human genome. CPO did not affect RSV replication in multicycle replication experiments in vitro. However, replication was marginally reduced in two rodents models. In hamsters, CPO RSVs induced lower levels of serum RSV-neutralizing antibodies. Thus, CPO of an RNA virus for a mammalian host has paradoxical effects on virus replication and the adaptive humoral immune response.

scholarly journals Nontypeable Haemophilus influenzae and Streptococcus pneumoniae bind respiratory syncytial virus glycoprotein

2007 ◽  
Vol 56 (9) ◽  
pp. 1133-1137 ◽  
Author(s):  
Vasanthi Avadhanula ◽  
Yan Wang ◽  
Allen Portner ◽  
Elisabeth Adderson
Keyword(s):  
Respiratory Syncytial Virus ◽  
Streptococcus Pneumoniae ◽  
Epithelial Cells ◽  
Haemophilus Influenzae ◽  
G Protein ◽  
Bacterial Infections ◽  
Dependent Manner ◽  
Rsv Infection ◽  
Membrane Bound ◽  
Syncytial Virus

Respiratory syncytial virus (RSV) infection is associated with secondary bacterial infections caused by nontypeable Haemophilus influenzae (NTHi) and Streptococcus pneumoniae. The pathogenesis of these complications is not completely understood; however, viral infection of respiratory epithelial cells promotes colonization by these bacteria. In the present study, RSV virions associated with NTHi and pneumococci in an inoculum-dependent manner in a fluid-phase binding assay. Adherence of NTHi and S. pneumoniae to epithelial cells transiently expressing RSV G glycoprotein was 2- and 2.2-fold higher, respectively, than adhesion to cells transfected with the vector alone (P <0.01). Furthermore, 4.6- and 6.2-fold larger numbers of NTHi and pneumococci bound to cells expressing a membrane-bound full-length RSV G protein than to cells expressing a truncated non-membrane-bound protein (P ≤0.005). Pre-incubating cells expressing membrane-bound G protein with blocking anti-RSV G antibodies reduced bacterial adherence by 78–84 % (P ≤0.005). These studies demonstrate that RSV G protein is a receptor for both NTHi and S. pneumoniae. Strategies to prevent this interaction may reduce the incidence of secondary bacterial complications of RSV infection.

scholarly journals Respiratory syncytial virus in severe lower respiratory infections in previously healthy young Ethiopian infants

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Abate Yeshidinber Weldetsadik ◽  
Frank Riedel
Keyword(s):  
Respiratory Syncytial Virus ◽  
Rainy Season ◽  
Clinical Laboratory ◽  
Respiratory Infections ◽  
Clinical Parameter ◽  
Imaging Data ◽  
Chi Square ◽  
Young Infants ◽  
Rsv Infection ◽  
Syncytial Virus

Abstract Background Respiratory Syncytial Virus (RSV) is the commonest cause of acute lower respiratory infections (ALRI) in infants. However, the burden of RSV is unknown in Ethiopia. We aimed to determine the prevalence, seasonality and predictors of RSV infection in young infants with ALRI for the first time in Ethiopia. Methods We performed RSV immuno-chromatographic assay from nasopharyngeal swabs of infants, 29 days to 6 months of age. We included the first 10 eligible infants in each month from June 2018 to May 2019 admitted in a tertiary pediatric center. Clinical, laboratory and imaging data were also collected, and chi-square test and regression were used to assess associated factors with RSV infection. Results Among a total of 117 study children, 65% were male and mean age was 3 months. Bronchiolitis was the commonest diagnosis (49%). RSV was isolated from 26 subjects (22.2%) of all ALRI, 37% of bronchiolitis and 11% of pneumonia patients. Although RSV infection occurred year round, highest rate extended from June to November. No clinical or laboratory parameter predicted RSV infection and only rainy season (Adjusted Odds Ratio (AOR) 10.46 [95%. C.I. 1.95, 56.18]) was independent predictor of RSV infection. Conclusions RSV was isolated in a fifth of young infants with severe ALRI, mostly in the rainy season. Diagnosis of RSV infection in our setting require specific tests as no clinical parameter predicted RSV infection. Since RSV caused less than a quarter of ALRI in our setting, the other causes should be looked for in future studies.

Sign in / Sign up

Export Citation Format

Share Document