scholarly journals Respiratory Syncytial Virus (RSV) Nonstructural (NS) Proteins as Host Range Determinants: a Chimeric Bovine RSV with NS Genes from Human RSV Is Attenuated in Interferon-Competent Bovine Cells

2002 ◽  
Vol 76 (9) ◽  
pp. 4287-4293 ◽  
Author(s):  
Birgit Bossert ◽  
Karl-Klaus Conzelmann
Keyword(s):  
Respiratory Syncytial Virus ◽  
Host Range ◽  
Vero Cells ◽  
Differential Protection ◽  
Wild Type ◽  
Nonstructural Proteins ◽  
Cellular Targets ◽  
Rational Development ◽  
Syncytial Virus ◽  
In Cells

ABSTRACT Bovine respiratory syncytial virus (BRSV) escapes from cellular responses to alpha/beta interferon (IFN-α/β) by a concerted action of the two viral nonstructural proteins, NS1 and NS2. Here we show that the NS proteins of human RSV (HRSV) are also able to counteract IFN responses and that they have the capacity to protect replication of an unrelated rhabdovirus. Even combinations of BRSV and HRSV NS proteins showed a protective activity, suggesting common mechanisms and cellular targets of HRSV and BRSV NS proteins. Although able to cooperate, NS proteins from BRSV and HRSV showed differential protection capacity in cells from different hosts. A chimeric BRSV with HRSV NS genes (BRSV h1/2) was severely attenuated in bovine IFN competent MDBK and Klu cells, whereas it replicated like BRSV in IFN-incompetent Vero cells or in IFN-competent human HEp-2 cells. After challenge with exogenous IFN-α, BRSV h1/2 was better protected than wild-type BRSV in human HEp-2 cells. In contrast, in cells of bovine origin, BRSV h1/2 was much less resistant to exogenous IFN than wild-type BRSV. These data demonstrate that RSV NS1 and NS2 proteins are major determinants of host range. The differential IFN escape capacity of RSV NS proteins in cells from different hosts provides a basis for rational development of attenuated live RSV vaccines.

scholarly journals Bovine Respiratory Syncytial Virus Nonstructural Proteins NS1 and NS2 Cooperatively Antagonize Alpha/Beta Interferon-Induced Antiviral Response

2000 ◽  
Vol 74 (18) ◽  
pp. 8234-8242 ◽  
Author(s):  
Jörg Schlender ◽  
Birgit Bossert ◽  
Ursula Buchholz ◽  
Karl-Klaus Conzelmann
Keyword(s):  
Respiratory Syncytial Virus ◽  
Vero Cells ◽  
Bovine Respiratory Syncytial Virus ◽  
Deletion Mutants ◽  
Nonstructural Proteins ◽  
Antiviral Responses ◽  
Fold Reduction ◽  
Mdbk Cells ◽  
Syncytial Virus ◽  
In Cells

ABSTRACT The functions of bovine respiratory syncytial virus (BRSV) nonstructural proteins NS1 and NS2 were studied by generation and analysis of recombinant BRSV carrying single and double gene deletions. Whereas in MDBK cells the lack of either or both NS genes resulted in a 5,000- to 10,000-fold reduction of virus titers, in Vero cells a moderate (10-fold) reduction was observed. Interestingly, cell culture supernatants from infected MDBK cells were able to restrain the growth of NS deletion mutants in Vero cells, suggesting the involvement of NS proteins in escape from cytokine-mediated host cell responses. The responsible factors in MDBK supernatants were identified as type I interferons by neutralization of the inhibitory effect with antibodies blocking the alpha interferon (IFN-α) receptor. Treatment of cells with recombinant universal IFN-α A/D or IFN-β revealed severe inhibition of single and double deletion mutants, whereas growth of full-length BRSV was not greatly affected. Surprisingly, all NS deletion mutants were equally repressed, indicating an obligatory cooperation of NS1 and NS2 in antagonizing IFN-mediated antiviral mechanisms. To verify this finding, we generated recombinant rabies virus (rRV) expressing either NS1 or NS2 and determined their IFN sensitivity. In cells coinfected with NS1- and NS2-expressing rRVs, virus replication was resistant to doses of IFN which caused a 1,000-fold reduction of replication in cells infected with wild-type RV or with each of the NS-expressing rRVs alone. Thus, BRSV NS proteins have the potential to cooperatively protect an unrelated virus from IFN-α/β mediated antiviral responses. Interestingly, BRSV NS proteins provided a more pronounced resistance to IFN in the bovine cell line MDBK than in cell lines of other origins, suggesting adaptation to host-specific antiviral responses. The findings described have a major impact on the design of live recombinant BRSV and HRSV vaccines.

scholarly journals Respiratory Syncytial Virus That Lacks Open Reading Frame 2 of the M2 Gene (M2-2) Has Altered Growth Characteristics and Is Attenuated in Rodents

2000 ◽  
Vol 74 (1) ◽  
pp. 74-82 ◽  
Author(s):  
Hong Jin ◽  
Xing Cheng ◽  
Helen Z. Y. Zhou ◽  
Shengqiang Li ◽  
Adam Seddiqui
Keyword(s):  
Respiratory Syncytial Virus ◽  
Cdna Clone ◽  
Open Reading Frame ◽  
Plaque Morphology ◽  
Potential Candidate ◽  
Wild Type ◽  
Replication Process ◽  
Reading Frame ◽  
Syncytial Virus ◽  
In Cells

ABSTRACT The M2 gene of respiratory syncytial virus (RSV) encodes two putative proteins: M2-1 and M2-2; both are believed to be involved in the RNA transcription or replication process. To understand the function of the M2-2 protein in virus replication, we deleted the majority of the M2-2 open reading frame from an infectious cDNA clone derived from the human RSV A2 strain. Transfection of HEp-2 cells with the cDNA clone containing the M2-2 deletion, together with plasmids that encoded the RSV N, P, and L proteins, produced a recombinant RSV that lacked the M2-2 protein (rA2ΔM2-2). Recombinant virus rA2ΔM2-2 was recovered and characterized. The levels of viral mRNA expression for 10 RSV genes examined were unchanged in cells infected with rA2ΔM2-2, except that a shorter M2 mRNA was detected. However, the ratio of viral genomic or antigenomic RNA to mRNA was reduced in rA2ΔM2-2-infected cells. By use of an antibody directed against the bacterially expressed M2-2 protein, the putative M2-2 protein was detected in cells infected with wild-type RSV but not in cells infected with rA2ΔM2-2. rA2ΔM2-2 displayed a small-plaque morphology and grew much more slowly than wild-type RSV in HEp-2 cells. In infected Vero cells, rA2ΔM2-2 exhibited very large syncytium formation compared to that of wild-type recombinant RSV. rA2ΔM2-2 appeared to be a host range mutant, since it replicated poorly in HEp-2, HeLa, and MRC5 cells but replicated efficiently in Vero and LLC-MK2 cells. Replication of rA2ΔM2-2 in the upper and lower respiratory tracts of mice and cotton rats was highly restricted. Despite its attenuated replication in rodents, rA2ΔM2-2 was able to provide protection against challenge with wild-type RSV A2. The genotype and phenotype of the M2-2 deletion mutant were stably maintained after extensive in vitro passages. The attenuated phenotype of rA2ΔM2-2 suggested that rA2ΔM2-2 may be a potential candidate for use as a live attenuated vaccine.

scholarly journals Respiratory Syncytial Virus Nonstructural Proteins NS1 and NS2 Mediate Inhibition of Stat2 Expression and Alpha/Beta Interferon Responsiveness

2005 ◽  
Vol 79 (14) ◽  
pp. 9315-9319 ◽  
Author(s):  
Mindy S. Lo ◽  
Robert M. Brazas ◽  
Michael J. Holtzman
Keyword(s):  
Respiratory Syncytial Virus ◽  
Host Range ◽  
Marked Decrease ◽  
Host Cells ◽  
Nonstructural Proteins ◽  
Beta Interferon ◽  
Rsv Infection ◽  
Alpha Beta ◽  
Syncytial Virus ◽  
Viral Host Range

ABSTRACT Respiratory syncytial virus (RSV) subverts the antiviral interferon (IFN) response, but the mechanism for this evasion was unclear. Here we show that RSV preferentially inhibits IFN-α/β signaling by expression of viral NS1 and NS2. Thus, RSV infection or expression of recombinant NS1 and NS2 in epithelial host cells causes a marked decrease in Stat2 levels and the consequent downstream IFN-α/β response. Similarly, NS1/NS2-deficient RSV no longer decreases Stat2 levels or IFN responsiveness. RSV infection decreased human but not mouse Stat2 levels, so this mechanism of IFN antagonism may contribute to viral host range, as well as immune subversion.

scholarly journals Effects of Nonstructural Proteins NS1 and NS2 of Human Respiratory Syncytial Virus on Interferon Regulatory Factor 3, NF-κB, and Proinflammatory Cytokines

2005 ◽  
Vol 79 (9) ◽  
pp. 5353-5362 ◽  
Author(s):  
Kirsten M. Spann ◽  
Kim C. Tran ◽  
Peter L. Collins
Keyword(s):  
Transcription Factors ◽  
Respiratory Syncytial Virus ◽  
Interferon Regulatory Factor ◽  
Human Respiratory Syncytial Virus ◽  
Wild Type ◽  
Regulatory Factor ◽  
Nonstructural Proteins ◽  
Vaccine Candidates ◽  
Attenuated Vaccine ◽  
Syncytial Virus

ABSTRACT Human respiratory syncytial virus (HRSV) is the leading cause of serious pediatric acute respiratory tract infections, and a better understanding is needed of the host response to HRSV and its attenuated vaccine derivatives. It has been shown previously that HRSV nonstructural proteins 1 and 2 (NS1 and NS2) inhibit the induction of alpha/beta interferon (IFN-α/β) in A549 cells and human macrophages. Two principal transcription factors for the early IFN-β and -α1 response are interferon regulatory factor 3 (IRF-3) and nuclear factor κB (NF-κB). At early times postinfection, wild-type HRSV and the NS1/NS2 deletion mutants were very similar in the ability to activate IRF-3. However, once NS1 and NS2 were expressed significantly, they acted cooperatively to suppress activation and nuclear translocation of IRF-3. Since these viruses differed greatly in the induction of IFN-α/β, NF-κB activation was evaluated in Vero cells, which lack the structural genes for IFN-α/β and would preclude confounding effects of IFN-α/β. This showed that deletion of the NS2 gene sharply reduced the ability of HRSV to induce activation of NF-κB. Since recombinant HRSVs from which the NS1 or NS2 genes have been deleted are being developed as vaccine candidates, we investigated whether the changes in activation of host transcription factors and increased IFN-α/β production had an effect on the epithelial production of proinflammatory factors. Viruses lacking NS1 and/or NS2 stimulated modestly lower production of RANTES (Regulated on Activation Normal T-cell Expressed and Secreted), interleukin 8, and tumor necrosis factor alpha compared to wild-type recombinant RSV, supporting their use as attenuated vaccine candidates.

scholarly journals Evolution of protection after maternal immunization for respiratory syncytial virus in cotton rats

2021 ◽  
Author(s):  
Jorge C.G. Blanco ◽  
Lori McGinnes-Cullen ◽  
Arash Kamali ◽  
Fatoumata Sylla ◽  
Marina Boukhavalova ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Neutralizing Antibody ◽  
Wild Type ◽  
Cotton Rat ◽  
Before And After ◽  
Boost Immunization ◽  
Cotton Rats ◽  
Antibody Titers ◽  
Syncytial Virus ◽  
Efficient Transfer

Maternal anti-respiratory syncytial virus (RSV) antibodies acquired by the fetus through the placenta protect neonates from RSV disease through the first weeks of life.  In the cotton rat model of RSV infections, we previously reported that immunization of dams during pregnancy with virus-like particles assembled with mutation stabilized pre-fusion F protein as well as the wild type G protein resulted in robust protection of their offspring from RSV challenge (Blanco, et al Journal of Virology 93: e00914-19, https://doi.org/10.1128/JVI.00914-19).  Here we describe the durability of those protective responses in dams, the durability of protection in offspring, and the transfer of that protection to offspring of two consecutive pregnancies without a second boost immunization.  We report that four weeks after birth, offspring of the first pregnancy were significantly protected from RSV replication in both lungs and nasal tissues after RSV challenge, but protection was reduced in pups at 6 weeks after birth.   However, the overall protection of offspring of the second pregnancy was considerably reduced, even at four weeks of age.  This drop in protection occurred even though the levels of total anti-pre-F IgG and neutralizing antibody titers in dams remained at similar, high levels before and after the second pregnancy.  The results are consistent with an evolution of antibody properties in dams to populations less efficiently transferred to offspring or the less efficient transfer of antibodies in elderly dams.

scholarly journals Respiratory Syncytial Virus Grown in Vero Cells Contains a Truncated Attachment Protein That Alters Its Infectivity and Dependence on Glycosaminoglycans

2009 ◽  
Vol 83 (20) ◽  
pp. 10710-10718 ◽  
Author(s):  
Steven Kwilas ◽  
Rachael M. Liesman ◽  
Liqun Zhang ◽  
Edward Walsh ◽  
Raymond J. Pickles ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
G Protein ◽  
Cell Cultures ◽  
Vero Cells ◽  
Target Cells ◽  
Apical Surface ◽  
Virus Attachment ◽  
C Terminus ◽  
Syncytial Virus

ABSTRACT Human respiratory syncytial virus (RSV) contains a heavily glycosylated 90-kDa attachment glycoprotein (G). Infection of HEp-2 and Vero cells in culture depends largely on virion G protein binding to cell surface glycosaminoglycans (GAGs). This GAG-dependent phenotype has been described for RSV grown in HEp-2 cells, but we have found that it is greatly reduced by a single passage in Vero cells. Virions produced from Vero cells primarily display a 55-kDa G glycoprotein. This smaller G protein represents a post-Golgi compartment form that is lacking its C terminus, indicating that the C terminus is required for GAG dependency. Vero cell-grown virus infected primary well-differentiated human airway epithelial (HAE) cell cultures 600-fold less efficiently than did HEp-2 cell-grown virus, indicating that the C terminus of the G protein is also required for virus attachment to this model of the in vivo target cells. This reduced infectivity for HAE cell cultures is not likely to be due to the loss of GAG attachment since heparan sulfate, the primary GAG used by RSV for attachment to HEp-2 cells, is not detectable at the apical surface of HAE cell cultures where RSV enters. Growing RSV stocks in Vero cells could dramatically reduce the initial infection of the respiratory tract in animal models or in volunteers receiving attenuated virus vaccines, thereby reducing the efficiency of infection or the efficacy of the vaccine.

Acetate Triggers Antiviral Response Mediated by RIG-I in Cells from Infants with Respiratory Syncytial Virus Bronchiolitis

2021 ◽  
Author(s):  
Krist Helen Antunes ◽  
Renato T. Stein ◽  
Caroline Franceschina ◽  
Emanuelle F. da Silva ◽  
Deise N. de Freitas ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Antiviral Response ◽  
Respiratory Syncytial Virus Bronchiolitis ◽  
Syncytial Virus ◽  
In Cells

scholarly journals Relevance of viral context and diversity of antigen-processing routes for respiratory syncytial virus cytotoxic T-lymphocyte epitopes

2008 ◽  
Vol 89 (9) ◽  
pp. 2194-2203 ◽  
Author(s):  
Carolina Johnstone ◽  
Sara Guil ◽  
Miguel A. Rico ◽  
Blanca García-Barreno ◽  
Daniel López ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Mhc Class I ◽  
Antigen Processing ◽  
Cytotoxic T Lymphocyte ◽  
Class I ◽  
F Protein ◽  
Mhc Class I Molecule ◽  
Presentation Pathway ◽  
Syncytial Virus ◽  
In Cells

Antigen processing of respiratory syncytial virus (RSV) fusion (F) protein epitopes F85–93 and F249–258 presented to cytotoxic T-lymphocytes (CTLs) by the murine major histocompatibility complex (MHC) class I molecule Kd was studied in different viral contexts. Epitope F85–93 was presented through a classical endogenous pathway dependent on the transporters associated with antigen processing (TAP) when the F protein was expressed from either RSV or recombinant vaccinia virus (rVACV). At least in cells infected with rVACV encoding either natural or cytosolic F protein, the proteasome was required for epitope processing. In cells infected with rVACV encoding the natural F protein, an additional endogenous TAP-independent presentation pathway was found for F85–93. In contrast, epitope F249–258 was presented only through TAP-independent pathways, but presentation was brefeldin A sensitive when the F protein was expressed from RSV, or mostly resistant when expressed from rVACV. Therefore, antigen-processing pathways with different mechanisms and subcellular localizations are accessible to individual epitopes presented by the same MHC class I molecule and processed from the same protein but in different viral contexts. This underscores both the diversity of pathways available and the influence of virus infection on presentation of epitopes to CTLs.

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