scholarly journals Human Respiratory Syncytial Virus Nonstructural Protein NS2 Antagonizes the Activation of Beta Interferon Transcription by Interacting with RIG-I

2009 ◽  
Vol 83 (8) ◽  
pp. 3734-3742 ◽  
Author(s):  
Zhenhua Ling ◽  
Kim C. Tran ◽  
Michael N. Teng
Keyword(s):  
Respiratory Syncytial Virus ◽  
Nonstructural Protein ◽  
Early Time ◽  
Human Respiratory Syncytial Virus ◽  
Wild Type ◽  
Promoter Activation ◽  
Rsv Infection ◽  
Infected Cells ◽  
Syncytial Virus ◽  
Irf3 Activation

ABSTRACT A wide variety of RNA viruses have been shown to produce proteins that inhibit interferon (IFN) production and signaling. For human respiratory syncytial virus (RSV), the nonstructural NS1 and NS2 proteins have been shown to block IFN signaling by causing the proteasomal degradation of STAT2. In addition, recombinant RSVs lacking either NS1 or NS2 induce more IFN production than wild-type (wt) RSV in infected cells. However, the mechanisms by which the NS proteins perform this function are unknown. In this study, we focused on defining the mechanism by which NS2 inhibits the induction of IFN transcription. We find that NS2 is required for the early inhibition of IFN transcription since the infection of cells with NS2-deletion RSV resulted in a higher level of IRF3 activation at early time points postinfection compared with that of wt or NS1-deletion RSV infection. In addition, NS2 expression inhibits IFN transcription induced by both the RIG-I and TLR3 pathways. Furthermore, we show that NS2 inhibits RIG-I-mediated IFN promoter activation by binding to the N-terminal CARD of RIG-I and inhibiting its interaction with the downstream component MAVS (IPS-1, VISA, Cardif). Thus, the RSV NS2 protein is a multifunctional IFN antagonist that targets specific components of both the IFN induction and IFN signaling pathways.

scholarly journals Evaluation of the Safety and Immune Efficacy of Recombinant Human Respiratory Syncytial Virus Strain Long Live Attenuated Vaccine Candidates

2021 ◽  
Author(s):  
Li-Nan Wang ◽  
Xiang-Lei Peng ◽  
Min Xu ◽  
Yuan-Bo Zheng ◽  
Yue-Ying Jiao ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Gene Deletion ◽  
Human Respiratory Syncytial Virus ◽  
Temperature Sensitive ◽  
T7 Promoter ◽  
Vaccine Candidates ◽  
Rsv Infection ◽  
Syncytial Virus

AbstractHuman respiratory syncytial virus (RSV) infection is the leading cause of lower respiratory tract illness (LRTI), and no vaccine against LRTI has proven to be safe and effective in infants. Our study assessed attenuated recombinant RSVs as vaccine candidates to prevent RSV infection in mice. The constructed recombinant plasmids harbored (5′ to 3′) a T7 promoter, hammerhead ribozyme, RSV Long strain antigenomic cDNA with cold-passaged (cp) mutations or cp combined with temperature-sensitive attenuated mutations from the A2 strain (A2cpts) or further combined with SH gene deletion (A2cptsΔSH), HDV ribozyme (δ), and a T7 terminator. These vectors were subsequently co-transfected with four helper plasmids encoding N, P, L, and M2-1 viral proteins into BHK/T7-9 cells, and the recovered viruses were then passaged in Vero cells. The rescued recombinant RSVs (rRSVs) were named rRSV-Long/A2cp, rRSV-Long/A2cpts, and rRSV-Long/A2cptsΔSH, respectively, and stably passaged in vitro, without reversion to wild type (wt) at sites containing introduced mutations or deletion. Although rRSV-Long/A2cpts and rRSV-Long/A2cptsΔSH displayed  temperature-sensitive (ts) phenotype in vitro and in vivo, all rRSVs were significantly attenuated in vivo. Furthermore, BALB/c mice immunized with rRSVs produced Th1-biased immune response, resisted wtRSV infection, and were free from enhanced respiratory disease. We showed that the combination of ΔSH with attenuation (att) mutations of cpts contributed to improving att phenotype, efficacy, and gene stability of rRSV. By successfully introducing att mutations and SH gene deletion into the RSV Long parent and producing three rRSV strains, we have laid an important foundation for the development of RSV live attenuated vaccines.

scholarly journals Eosinophils contribute to innate antiviral immunity and promote clearance of respiratory syncytial virus

Blood ◽  
2007 ◽  
Vol 110 (5) ◽  
pp. 1578-1586 ◽  
Author(s):  
Simon Phipps ◽  
Chuan En Lam ◽  
Suresh Mahalingam ◽  
Matthew Newhouse ◽  
Ruben Ramirez ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Host Defense ◽  
No Production ◽  
Wild Type ◽  
Interleukin 5 ◽  
Virus Clearance ◽  
Lung Dysfunction ◽  
Rsv Infection ◽  
Syncytial Virus

AbstractEosinophils are recruited to the lungs in response to respiratory syncytial virus (RSV) infection; however, their role in promoting antiviral host defense remains unclear. Here, we demonstrate that eosinophils express TLRs that recognize viral nucleic acids, are activated and degranulate after single-stranded RNA (ssRNA) stimulation of the TLR-7–MyD88 pathway, and provide host defense against RSV that is MyD88 dependent. In contrast to wild-type mice, virus clearance from lung tissue was more rapid in hypereosinophilic (interleukin-5 transgenic) mice. Transfer of wild-type but not MyD88-deficient eosinophils to the lungs of RSV-infected wild-type mice accelerated virus clearance and inhibited the development of airways hyperreactivity. Similar responses were observed when infected recipient mice were MyD88 deficient. Eosinophils isolated from infected hypereosinophilic MyD88-sufficient but not MyD88-deficient mice expressed greater amounts of IFN regulatory factor (IRF)–7 and eosinophil-associated ribonucleases EAR-1 and EAR-2. Hypereosinophilia in the airways of infected mice also correlated with increased expression of IRF-7, IFN-β, and NOS-2, and inhibition of NO production with the NOS-2 inhibitor L-NMA partially reversed the accelerated virus clearance promoted by eosinophils. Collectively, our results demonstrate that eosinophils can protect against RSV in vivo, as they promote virus clearance and may thus limit virus-induced lung dysfunction.

scholarly journals Interferon-Induced Protein 44 and Interferon-Induced Protein 44-Like Restrict Replication of Respiratory Syncytial Virus

2020 ◽  
Vol 94 (18) ◽  
Author(s):  
D. C. Busse ◽  
D. Habgood-Coote ◽  
S. Clare ◽  
C. Brandt ◽  
I. Bassano ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Mouse Model ◽  
Severe Disease ◽  
Early Time ◽  
Airway Epithelial Cells ◽  
Knockout Mouse Model ◽  
Antiviral Genes ◽  
Wide Range ◽  
Rsv Infection ◽  
Syncytial Virus

ABSTRACT Cellular intrinsic immunity, mediated by the expression of an array of interferon-stimulated antiviral genes, is a vital part of host defense. We have previously used a bioinformatic screen to identify two interferon-stimulated genes (ISG) with poorly characterized function, interferon-induced protein 44 (IFI44) and interferon-induced protein 44-like (IFI44L), as potentially being important in respiratory syncytial virus (RSV) infection. Using overexpression systems, CRISPR-Cas9-mediated knockout, and a knockout mouse model, we investigated the antiviral capability of these genes in the control of RSV replication. Overexpression of IFI44 or IFI44L was sufficient to restrict RSV infection at an early time postinfection. Knocking out these genes in mammalian airway epithelial cells increased levels of infection. Both genes express antiproliferative factors that have no effect on RSV attachment but reduce RSV replication in a minigenome assay. The loss of Ifi44 was associated with a more severe infection phenotype in a mouse model of infection. These studies demonstrate a function for IFI44 and IFI44L in controlling RSV infection. IMPORTANCE RSV infects all children under 2 years of age, but only a subset of children get severe disease. We hypothesize that susceptibility to severe RSV necessitating hospitalization in children without predefined risk factors is, in part, mediated at the antiviral gene level. However, there is a large array of antiviral genes, particularly in the ISG family, the mechanism of which is poorly understood. Having previously identified IFI44 and IFI44L as possible genes of interest in a bioinformatic screen, we dissected the function of these two genes in the control of RSV. Through a range of overexpression and knockout studies, we show that the genes are antiviral and antiproliferative. This study is important because IFI44 and IFI44L are upregulated after a wide range of viral infections, and IFI44L can serve as a diagnostic biomarker of viral infection.

scholarly journals RAGE inhibits human respiratory syncytial virus syncytium formation by interfering with F-protein function

2013 ◽  
Vol 94 (8) ◽  
pp. 1691-1700 ◽  
Author(s):  
Jane Tian ◽  
Kelly Huang ◽  
Subramaniam Krishnan ◽  
Catherine Svabek ◽  
Daniel C. Rowe ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Epithelial Cells ◽  
Syncytium Formation ◽  
Human Respiratory Syncytial Virus ◽  
Host Cells ◽  
Type I ◽  
F Protein ◽  
Viral Spread ◽  
Infected Cells ◽  
Syncytial Virus

Human respiratory syncytial virus (RSV) is a major cause of severe lower respiratory tract infection. Infection is critically dependent on the RSV fusion (F) protein, which mediates fusion between the viral envelope and airway epithelial cells. The F protein is also expressed on infected cells and is responsible for fusion of infected cells with adjacent cells, resulting in the formation of multinucleate syncytia. The receptor for advanced glycation end products (RAGE) is a pattern-recognition receptor that is constitutively highly expressed by type I alveolar epithelial cells. Here, we report that RAGE protected HEK cells from RSV-induced cell death and reduced viral titres in vitro. RAGE appeared to interact directly with the F protein, but, rather than inhibiting RSV entry into host cells, virus replication and budding, membrane-expressed RAGE or soluble RAGE blocked F-protein-mediated syncytium formation and sloughing. These data indicate that RAGE may contribute to protecting the lower airways from RSV by inhibiting the formation of syncytia, viral spread, epithelial damage and airway obstruction.

scholarly journals Respiratory Syncytial Virus Infection Sensitizes Cells to Apoptosis Mediated by Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand

2003 ◽  
Vol 77 (17) ◽  
pp. 9156-9172 ◽  
Author(s):  
Alexander Kotelkin ◽  
Elena A. Prikhod'ko ◽  
Jeffrey I. Cohen ◽  
Peter L. Collins ◽  
Alexander Bukreyev
Keyword(s):  
Respiratory Syncytial Virus ◽  
Tumor Necrosis Factor ◽  
Transcriptional Activation ◽  
Tumor Necrosis ◽  
Death Receptor ◽  
Rnase Protection ◽  
Rsv Infection ◽  
Infected Cells ◽  
Syncytial Virus ◽  
Necrosis Factor

ABSTRACT Respiratory syncytial virus (RSV) is an important cause of respiratory tract disease worldwide, especially in the pediatric population. For viruses in general, apoptotic death of infected cells is a mechanism for reducing virus replication. Apoptosis can also be an important factor in augmenting antigen presentation and the host immune response. We examined apoptosis in response to RSV infection of primary small airway cells, primary tracheal-bronchial cells, and A549 and HEp-2 cell lines. The primary cells and the A549 cell line gave generally similar responses, indicating their appropriateness as models in contrast to HEp-2 cells. With the use of RNase protection assays with probes representing 33 common apoptosis factors, we found strong transcriptional activation of both pro- and antiapoptotic factors in response to RSV infection, which were further studied at the protein level and by functional assays. In particular, RSV infection strongly up-regulated the expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and its functional receptors death receptor 4 (DR4) and DR5. Furthermore, RSV-infected cells became highly sensitive to apoptosis induced by exogenous TRAIL. These findings suggest that RSV-infected cells in vivo are susceptible to killing through the TRAIL pathway by immune cells such as natural killer and CD4+ cells that bear membrane-bound TRAIL. RSV infection also induced several proapoptotic factors of the Bcl-2 family and caspases 3, 6, 7, 8, 9, and 10, representing both the death receptor- and mitochondrion-dependent apoptotic pathways. RSV also mediated the strong induction of antiapoptotic factors of the Bcl-2 family, especially Mcl-1, which might account for the delayed induction of apoptosis in RSV-infected cells in the absence of exogenous induction of the TRAIL pathway.

scholarly journals Requirements for Human Respiratory Syncytial Virus Glycoproteins in Assembly and Egress from Infected Cells

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Melissa Batonick ◽  
Gail W. Wertz
Keyword(s):  
Plasma Membrane ◽  
Respiratory Syncytial Virus ◽  
G Proteins ◽  
Matrix Protein ◽  
Protein Localization ◽  
Viral Proteins ◽  
Human Respiratory Syncytial Virus ◽  
The Other ◽  
Infected Cells ◽  
Syncytial Virus

Human respiratory syncytial virus (HRSV) is an enveloped RNA virus that assembles and buds from the plasma membrane of infected cells. The ribonucleoprotein complex (RNP) must associate with the viral matrix protein and glycoproteins to form newly infectious particles prior to budding. The viral proteins involved in HRSV assembly and egress are mostly unexplored. We investigated whether the glycoproteins of HRSV were involved in the late stages of viral replication by utilizing recombinant viruses where each individual glycoprotein gene was deleted and replaced with a reporter gene to maintain wild-type levels of gene expression. These engineered viruses allowed us to study the roles of the glycoproteins in assembly and budding in the context of infectious virus. Microscopy data showed that the F glycoprotein was involved in the localization of the glycoproteins with the other viral proteins at the plasma membrane. Biochemical analyses showed that deletion of the F and G proteins affected incorporation of the other viral proteins into budded virions. However, efficient viral release was unaffected by the deletion of any of the glycoproteins individually or in concert. These studies attribute a novel role to the F and G proteins in viral protein localization and assembly.

scholarly journals Structural basis for IFN antagonism by human respiratory syncytial virus nonstructural protein 2

2021 ◽  
Vol 118 (10) ◽  
pp. e2020587118
Author(s):  
Jingjing Pei ◽  
Nicole D. Wagner ◽  
Angela J. Zou ◽  
Srirupa Chatterjee ◽  
Dominika Borek ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Messenger Rna ◽  
Molecular Mechanisms ◽  
Nonstructural Protein ◽  
Human Respiratory Syncytial Virus ◽  
Host Responses ◽  
Structural Basis ◽  
Downstream Signaling ◽  
Nonstructural Protein 2 ◽  
Syncytial Virus

Human respiratory syncytial virus (RSV) nonstructural protein 2 (NS2) inhibits host interferon (IFN) responses stimulated by RSV infection by targeting early steps in the IFN-signaling pathway. But the molecular mechanisms related to how NS2 regulates these processes remain incompletely understood. To address this gap, here we solved the X-ray crystal structure of NS2. This structure revealed a unique fold that is distinct from other known viral IFN antagonists, including RSV NS1. We also show that NS2 directly interacts with an inactive conformation of the RIG-I–like receptors (RLRs) RIG-I and MDA5. NS2 binding prevents RLR ubiquitination, a process critical for prolonged activation of downstream signaling. Structural analysis, including by hydrogen-deuterium exchange coupled to mass spectrometry, revealed that the N terminus of NS2 is essential for binding to the RIG-I caspase activation and recruitment domains. N-terminal mutations significantly diminish RIG-I interactions and result in increased IFNβ messenger RNA levels. Collectively, our studies uncover a previously unappreciated regulatory mechanism by which NS2 further modulates host responses and define an approach for targeting host responses.

scholarly journals Obtaining and Characterization of the Monoclonal Antibodies Against G-Protein of the Respiratory Syncytial Virus

2020 ◽  
pp. 7-14
Author(s):  
N. A. Demidova ◽  
R. R. Klimova ◽  
A. A. Kushch ◽  
E. I. Lesnova ◽  
O. V. Masalova ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Respiratory Syncytial Virus ◽  
G Protein ◽  
Clinical Samples ◽  
Enzyme Linked Immunosorbent Assay ◽  
Rsv Infection ◽  
Hybridoma Technology ◽  
Infected Cells ◽  
Syncytial Virus

The aim of this study was to obtain hybridomas producing monoclonal antibodies (Mabs) to the G-protein of the respiratory syncytial virus (RSV), and to evaluate their immunological characteristics and virus-neutralizing activity.Material and methods. Mouse Mabs were obtained using hybridoma technology. The properties of Mabs were studied by enzyme-linked immunosorbent assay (ELISA), immunofluorescence staining (IF) of infected cells, as well as by biological neutralization test in vitro (NT). To identify epitopes recognized by the Mabs on G protein ELISA additivity test was used.Results. Hybridization of splenocytes with Sp2/0 myeloma cells and primary screening showed that 75 hybridomas produce antibodies interacting with purified virus, 17 of them also react with the recombinant G-protein in ELISA. In NT 4, hybridomas suppressed in vitro RSV infection by more than 50%. Cloning of these hybridomas revealed 4 monoclones producing the most active Mabs. Mab 1C11 was IgG2a, 3 others (5D4, 5G11 and 6H4) were IgM. Three IgM Mabs actively reacted with both RSV A2 and Long, and with G-protein; Mab 1C11 was less reactive with all antigens tested. All Mabs suppressed RSV infection, while Mab 5D4 supressed it almost completely (98%). IF analysis showed that all Mabs detected RSV G-protein in the cell cytoplasm, the largest number of infected cells was detected using Mab 5D4 (80%). It was shown that the isolated Mabs were directed to two non-overlapping epitopes on the RSV G-protein.Conclusion. The isolated Mabs can be used to detect RSV in clinical samples by ELISA and IF. The isolated Mabs can be used for humanized recombinant antibodies construction and for the treatment of RSV infection in future.

scholarly journals Heparin-Like Structures on Respiratory Syncytial Virus Are Involved in Its Infectivity In Vitro

1998 ◽  
Vol 72 (9) ◽  
pp. 7221-7227 ◽  
Author(s):  
C. Bourgeois ◽  
J. B. Bour ◽  
K. Lidholt ◽  
C. Gauthray ◽  
P. Pothier
Keyword(s):  
Respiratory Syncytial Virus ◽  
Heparan Sulfate ◽  
G Protein ◽  
Enzymatic Digestion ◽  
Virus Infectivity ◽  
Rsv Infection ◽  
Infected Cells ◽  
Virus Culture ◽  
Syncytial Virus

ABSTRACT Addition of heparin to the virus culture inhibited syncytial plaque formation due to respiratory syncytial virus (RSV). Moreover, pretreatment of the virus with heparinase or an inhibitor of heparin, protamine, greatly reduced virus infectivity. Two anti-heparan sulfate antibodies stained RSV-infected cells, but not noninfected cells, by immunofluorescence. One of the antibodies was capable of neutralizing RSV infection in vitro. These results prove that heparin-like structures identified on RSV play a major role in early stages of infection. The RSV G protein is the attachment protein. Both anti-heparan sulfate antibodies specifically bound to this protein. Enzymatic digestion of polysaccharides in the G protein reduced the binding, which indicates that heparin-like structures are on the G protein. Such oligosaccharides may therefore participate in the attachment of the virus.

scholarly journals Brief History and Characterization of Enhanced Respiratory Syncytial Virus Disease

2015 ◽  
Vol 23 (3) ◽  
pp. 189-195 ◽  
Author(s):  
Patricio L. Acosta ◽  
Mauricio T. Caballero ◽  
Fernando P. Polack
Keyword(s):  
Respiratory Syncytial Virus ◽  
Virus Disease ◽  
Wild Type Virus ◽  
Wild Type ◽  
T Helper ◽  
Vaccine Candidates ◽  
Rsv Infection ◽  
Syncytial Virus ◽  
Complex Deposition

ABSTRACTIn 1967, infants and toddlers immunized with a formalin-inactivated vaccine against respiratory syncytial virus (RSV) experienced an enhanced form of RSV disease characterized by high fever, bronchopneumonia, and wheezing when they became infected with wild-type virus in the community. Hospitalizations were frequent, and two immunized toddlers died upon infection with wild-type RSV. The enhanced disease was initially characterized as a “peribronchiolar monocytic infiltration with some excess in eosinophils.” Decades of research defined enhanced RSV disease (ERD) as the result of immunization with antigens not processed in the cytoplasm, resulting in a nonprotective antibody response and CD4+T helper priming in the absence of cytotoxic T lymphocytes. This response to vaccination led to a pathogenic Th2 memory response with eosinophil and immune complex deposition in the lungs after RSV infection. In recent years, the field of RSV experienced significant changes. Numerous vaccine candidates with novel designs and formulations are approaching clinical trials, defying our previous understanding of favorable parameters for ERD. This review provides a succinct analysis of these parameters and explores criteria for assessing the risk of ERD in new vaccine candidates.

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