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Small hydrophobic protein of human metapneumovirus does not affect virus replication and host gene expression in vitro. PLoS One 2013; 8:e58572. [PMID: 23484037 PMCID: PMC3590193 DOI: 10.1371/journal.pone.0058572] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 02/07/2013] [Indexed: 12/11/2022] Open
Abstract
Human metapneumovirus (HMPV) encodes a small hydrophobic (SH) protein of unknown function. HMPV from which the SH open reading frame was deleted (HMPVΔSH) was viable and displayed similar replication kinetics, cytopathic effect and plaque size compared with wild type HMPV in several cell-lines. In addition, no differences were observed in infection efficiency or cell-to-cell spreading in human primary bronchial epithelial cells (HPBEC) cultured at an air-liquid interphase. Host gene expression was analyzed in A549 cells infected with HMPV or HMPVΔSH using microarrays and mass spectrometry (MS) based techniques at multiple time points post infection. Only minor differences were observed in mRNA or protein expression levels. A possible function of HMPV SH as apoptosis blocker, as proposed for several members of the family Paramyxoviridae, was rejected based on this analysis. So far, a clear phenotype of HMPV SH deletion mutants in vitro at the virus and host levels is absent.
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Rudraraju R, Jones BG, Sealy R, Surman SL, Hurwitz JL. Respiratory syncytial virus: current progress in vaccine development. Viruses 2013; 5:577-94. [PMID: 23385470 PMCID: PMC3640515 DOI: 10.3390/v5020577] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 02/01/2013] [Accepted: 02/04/2013] [Indexed: 12/18/2022] Open
Abstract
Respiratory syncytial virus (RSV) is the etiological agent for a serious lower respiratory tract disease responsible for close to 200,000 annual deaths worldwide. The first infection is generally most severe, while re-infections usually associate with a milder disease. This observation and the finding that re-infection risks are inversely associated with neutralizing antibody titers suggest that immune responses generated toward a first RSV exposure can significantly reduce morbidity and mortality throughout life. For more than half a century, researchers have endeavored to design a vaccine for RSV that can mimic or improve upon natural protective immunity without adverse events. The virus is herein described together with the hurdles that must be overcome to develop a vaccine and some current vaccine development approaches.
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Affiliation(s)
- Rajeev Rudraraju
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA; E-Mails: (R.R.); (B.J.); (R.S.); (S.S.)
| | - Bart G. Jones
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA; E-Mails: (R.R.); (B.J.); (R.S.); (S.S.)
| | - Robert Sealy
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA; E-Mails: (R.R.); (B.J.); (R.S.); (S.S.)
| | - Sherri L. Surman
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA; E-Mails: (R.R.); (B.J.); (R.S.); (S.S.)
| | - Julia L. Hurwitz
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA; E-Mails: (R.R.); (B.J.); (R.S.); (S.S.)
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, 858 Madison Avenue, Memphis, TN 38163, USA
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Barik S. Respiratory syncytial virus mechanisms to interfere with type 1 interferons. Curr Top Microbiol Immunol 2013; 372:173-91. [PMID: 24362690 DOI: 10.1007/978-3-642-38919-1_9] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Respiratory syncytial virus (RSV) is a member of the Paramyxoviridae family that consists of viruses with nonsegmented negative-strand RNA genome. Infection by these viruses triggers the innate antiviral response of the host, mainly type I interferon (IFN). Essentially all other viruses of this family produce IFN suppressor functions by co-transcriptional RNA editing. In contrast, RSV has evolved two unique nonstructural proteins, NS1 and NS2, to effectively serve this purpose. Together, NS1 and NS2 degrade or sequester multiple signaling proteins that affect both IFN induction and IFN effector functions. While the mechanism of action of NS1 and NS2 is a subject of active research, their effect on adaptive immunity is also being recognized. In this review, we discuss various aspects of NS1 and NS2 function with implications for vaccine design.
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Affiliation(s)
- Sailen Barik
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological and Environmental Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH, 44115, USA,
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Respiratory syncytial virus modified by deletions of the NS2 gene and amino acid S1313 of the L polymerase protein is a temperature-sensitive, live-attenuated vaccine candidate that is phenotypically stable at physiological temperature. J Virol 2012; 87:1985-96. [PMID: 23236065 DOI: 10.1128/jvi.02769-12] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human respiratory syncytial virus (RSV) is the leading viral cause of lower respiratory tract disease in infants and children worldwide. In previous work to develop point mutations in RSV with improved genetic stability, we observed that an attenuating mutation at amino acid position 1321 in the L polymerase protein was subject to deattenuation by a spontaneous second-site compensatory mutation at position 1313 (C. Luongo, C. C. Winter, P. L. Collins, and U. J. Buchholz, J. Virol. 86:10792-10804, 2012). In the present study, we found that deletion of position 1313 (Δ1313), irrespective of the presence of an attenuating mutation at position 1321, provided a new attenuating mutation. RSV bearing Δ1313 replicated in cell culture as efficiently as wild-type virus at 32°C, was restricted for replication at 37°C, and was restricted 50-fold and 150-fold in the upper and lower respiratory tracts, respectively, of mice. We combined the Δ1313 deletion with the previously described, attenuating NS2 gene deletion (ΔNS2) to produce the recombinant live-attenuated RSV vaccine candidate ΔNS2/Δ1313. During in vitro stress tests involving serial passage at incrementally increasing temperatures, a second-site compensatory mutation was detected in close proximity of Δ1313, namely, I1314T. This site was genetically and phenotypically stabilized by an I1314L substitution. Combination of I1314L with ΔNS2/Δ1313 yielded a virus, ΔNS2/Δ1313/1314L, with genetic stability at physiological temperature. This stabilized vaccine candidate was moderately temperature sensitive and had a level of restriction in chimpanzees comparable to that of MEDI-559, a promising RSV vaccine candidate that presently is in clinical trials but lacks stabilized attenuating mutations. The level of attenuation and genetic stability identify ΔNS2/Δ1313/1314L as a promising candidate for evaluation in pediatric phase I studies.
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Tan YR, Peng D, Chen CM, Qin XQ. Nonstructural protein-1 of respiratory syncytial virus regulates HOX gene expression through interacting with histone. Mol Biol Rep 2012; 40:675-9. [PMID: 23054021 DOI: 10.1007/s11033-012-2107-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 10/03/2012] [Indexed: 12/23/2022]
Abstract
Human respiratory syncytial virus (RSV), a major cause of severe respiratory diseases, constitutes an important risk factor for the development of subsequent asthma. In searching for its mechanism, the present study was designed to screen the interacting proteins of two important nonstructural (NS) proteins in human BECs. The subcellular localization and the effects of NS on HOX gene expression were also examined. The results showed that NS1 was distributed throughout the nucleus and cytoplasm, while NS2 was mainly distributed in cytoplasm of BECs. NS1 interacted specifically with host histone H2BD, inducing histone ubiquitination and subsequent HOX gene expression. In conclusion, the results of the present study indicated that RSV NS-1 induces HOX gene expression, through histone ubiquitination in a BEC cell line, which may provide a novel conception for understanding the relationship between severe RSV bronchiolitis during early life and the development of subsequent asthma.
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Affiliation(s)
- Yu-Rong Tan
- Department of Basic Medical, Xiangya School of Medicine, Central South University, Changsha 410078, Hunan, China
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57
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Human metapneumovirus M2-2 protein inhibits innate cellular signaling by targeting MAVS. J Virol 2012; 86:13049-61. [PMID: 23015697 DOI: 10.1128/jvi.01248-12] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Human metapneumovirus (hMPV) is a leading cause of respiratory infections in pediatric populations globally, with no prophylactic or therapeutic measures. Recently, a recombinant hMPV lacking the M2-2 protein (rhMPV-ΔM2-2) demonstrated reduced replication in the respiratory tract of animal models, making it a promising live vaccine candidate. However, the exact nature of the interaction between the M2-2 protein and host cells that regulates viral infection/propagation is largely unknown. By taking advantage of the available reverse genetics system and ectopic expression system for viral protein, we found that M2-2 not only promotes viral gene transcription and replication but subverts host innate immunity, therefore identifying M2-2 as a novel virulence factor, in addition to the previously described hMPV G protein. Since we have shown that the RIG-I/MAVS pathway plays an important role in hMPV-induced signaling in airway epithelial cells, we investigated whether M2-2 antagonizes the host cellular responses by targeting this pathway. Reporter gene assays and coimmunoprecipitation studies indicated that M2-2 targets MAVS, an inhibitory mechanism different from what we previously reported for hMPV G, which affects RIG-I- but not MAVS-dependent gene transcription. In addition, we found that the domains of M2-2 responsible for the regulation of viral gene transcription and antiviral signaling are different. Our findings collectively demonstrate that M2-2 contributes to hMPV immune evasion through the inhibition of MAVS-dependent cellular responses.
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58
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Mok H, Cheng X, Xu Q, Zengel JR, Parhy B, Zhao J, Wang CK, Jin H. Evaluation of Measles Vaccine Virus as a Vector to Deliver Respiratory Syncytial Virus Fusion Protein or Epstein-Barr Virus Glycoprotein gp350. Open Virol J 2012; 6:12-22. [PMID: 22383906 PMCID: PMC3286841 DOI: 10.2174/1874357901206010012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 01/03/2012] [Accepted: 01/16/2012] [Indexed: 01/31/2023] Open
Abstract
Live attenuated recombinant measles vaccine virus (MV) Edmonston-Zagreb (EZ) strain was evaluated as a viral vector to express the ectodomains of fusion protein of respiratory syncytial virus (RSV F) or glycoprotein 350 of Epstein-Barr virus (EBV gp350) as candidate vaccines for prophylaxis of RSV and EBV. The glycoprotein gene was inserted at the 1st or the 3rd position of the measles virus genome and the recombinant viruses were generated. Insertion of the foreign gene at the 3rd position had a minimal impact on viral replication in vitro. RSV F or EBV gp350 protein was secreted from infected cells. In cotton rats, EZ-RSV F and EZ-EBV gp350 induced MV- and insert-specific antibody responses. In addition, both vaccines also induced insert specific interferon gamma (IFN-γ) secreting T cell response. EZ-RSV F protected cotton rats from pulmonary replication of RSV A2 challenge infection. In rhesus macaques, although both EZ-RSV F and EZ-EBV gp350 induced MV specific neutralizing antibody responses, only RSV F specific antibody response was detected. Thus, the immunogenicity of the foreign antigens delivered by measles vaccine virus is dependent on the nature of the insert and the animal models used for vaccine evaluation.
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Affiliation(s)
- Hoyin Mok
- MedImmune LLC., 319 North Bernardo Ave, Mountain View, California, USA
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59
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Hastie ML, Headlam MJ, Patel NB, Bukreyev AA, Buchholz UJ, Dave KA, Norris EL, Wright CL, Spann KM, Collins PL, Gorman JJ. The human respiratory syncytial virus nonstructural protein 1 regulates type I and type II interferon pathways. Mol Cell Proteomics 2012; 11:108-27. [PMID: 22322095 PMCID: PMC3418853 DOI: 10.1074/mcp.m111.015909] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Respiratory syncytial viruses encode a nonstructural protein (NS1) that interferes with type I and III interferon and other antiviral responses. Proteomic studies were conducted on human A549 type II alveolar epithelial cells and type I interferon-deficient Vero cells (African green monkey kidney cells) infected with wild-type and NS1-deficient clones of human respiratory syncytial virus to identify other potential pathway and molecular targets of NS1 interference. These analyses included two-dimensional differential gel electrophoresis and quantitative Western blotting. Surprisingly, NS1 was found to suppress the induction of manganese superoxide dismutase (SOD2) expression in A549 cells and to a much lesser degree Vero cells in response to infection. Because SOD2 is not directly inducible by type I interferons, it served as a marker to probe the impact of NS1 on signaling of other cytokines known to induce SOD2 expression and/or indirect effects of type I interferon signaling. Deductive analysis of results obtained from cell infection and cytokine stimulation studies indicated that interferon-γ signaling was a potential target of NS1, possibly as a result of modulation of STAT1 levels. However, this was not sufficient to explain the magnitude of the impact of NS1 on SOD2 induction in A549 cells. Vero cell infection experiments indicated that NS1 targeted a component of the type I interferon response that does not directly induce SOD2 expression but is required to induce another initiator of SOD2 expression. STAT2 was ruled out as a target of NS1 interference using quantitative Western blot analysis of infected A549 cells, but data were obtained to indicate that STAT1 was one of a number of potential targets of NS1. A label-free mass spectrometry-based quantitative approach is proposed as a means of more definitive identification of NS1 targets.
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Affiliation(s)
- Marcus L Hastie
- Protein Discovery Centre, Queensland Institute of Medical Research, Herston, Queensland 4029, Australia
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Abstract
Viral respiratory infections cause significant morbidity and mortality in infants and young children as well as in at-risk adults and the elderly. Although many viral pathogens are capable of causing respiratory disease, vaccine development has to focus on a limited number of pathogens, such as those that commonly cause serious lower respiratory illness (LRI). Whereas influenza virus vaccines have been available for some time (see the review by Clark and Lynch in this issue), vaccines against other medically important viruses such as respiratory syncytial virus (RSV), the parainfluenza viruses (PIVs), and metapneumovirus (MPVs) are not available. This review aims to provide a brief update on investigational vaccines against RSV, the PIVs, and MPV that have been evaluated in clinical trials or are currently in clinical development.
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Affiliation(s)
- Alexander C Schmidt
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 10001, USA.
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Ren J, Liu T, Pang L, Li K, Garofalo RP, Casola A, Bao X. A novel mechanism for the inhibition of interferon regulatory factor-3-dependent gene expression by human respiratory syncytial virus NS1 protein. J Gen Virol 2011; 92:2153-2159. [PMID: 21632562 DOI: 10.1099/vir.0.032987-0] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human respiratory syncytial virus (RSV), a leading cause of respiratory tract infections in infants, inhibits type I interferon (IFN)-dependent signalling, as well as IFN synthesis. RSV non-structural protein NS1 plays a significant role in this inhibition; however, the mechanism(s) responsible is not fully known. The transcription factor interferon regulatory factor (IRF)-3 is essential for viral-induced IFN-β synthesis. In this study, we found that NS1 protein inhibits IRF-3-dependent gene transcription in constitutively active IRF-3 overexpressing cells, demonstrating that NS1 directly targets IRF-3. Our data also demonstrate that NS1 associates with IRF-3 and its transcriptional coactivator CBP, leading to disrupted association of IRF-3 to CBP and subsequent reduced binding of IRF-3 to the IFN-β promoter without blocking viral-induced IRF-3 phosphorylation, nuclear translocation and dimerization, thereby identifying a novel molecular mechanism by which RSV inhibits IFN-β synthesis.
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Affiliation(s)
- Junping Ren
- Department of Pediatrics, University of Texas Medical Branch, Galveston, TX, USA
| | - Tianshuang Liu
- Department of Pediatrics, University of Texas Medical Branch, Galveston, TX, USA
| | - Lan Pang
- Department of Pediatrics, University of Texas Medical Branch, Galveston, TX, USA
| | - Kui Li
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Roberto P Garofalo
- Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX, USA.,Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA.,Department of Pediatrics, University of Texas Medical Branch, Galveston, TX, USA
| | - Antonella Casola
- Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX, USA.,Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA.,Department of Pediatrics, University of Texas Medical Branch, Galveston, TX, USA
| | - Xiaoyong Bao
- Department of Pediatrics, University of Texas Medical Branch, Galveston, TX, USA
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Straub CP, Lau WH, Preston FM, Headlam MJ, Gorman JJ, Collins PL, Spann KM. Mutation of the elongin C binding domain of human respiratory syncytial virus non-structural protein 1 (NS1) results in degradation of NS1 and attenuation of the virus. Virol J 2011; 8:252. [PMID: 21600055 PMCID: PMC3121706 DOI: 10.1186/1743-422x-8-252] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 05/22/2011] [Indexed: 11/13/2022] Open
Abstract
Background Human respiratory syncytial virus (RSV) is an important cause of lower respiratory tract disease in the paediatic population, immunocompromised individuals and the elderly worldwide. However, despite global efforts over the past several decades there are no commercially available vaccines. RSV encodes 2 non-structural proteins, NS1 and NS2, that are type I interferon antagonists. RSV restricts type I interferon signaling and the expression of antiviral genes by degrading STAT2. It has been proposed that NS1 binds to elongin C to form a ubiquitin ligase (E3) complex that targets STAT2 for ubiquitination and proteosomal degradation. Results Here, we have engineered a live recombinant RSV in which the 3 consensus amino acids of the NS1 elongin C binding domain have been replaced with alanine (NS1F-ELCmut). Mutation of this region of NS1 resulted in attenuation of RSV replication in A549 cells to levels similar to that observed when the NS1 gene is completely deleted (ΔNS1). This mutation also resulted in moderate attenuation in Vero cells. Attenuation was correlated to intracellular degradation of the mutated NS1 protein. Time course analysis showed that mutant NS1 protein accumulated in cytoplasmic bodies that contained the lysosomal marker LAMP1. However lack of cleavage of LC3 suggested that autophagy was not involved. Induction of IFN-β mRNA expression also was observed in association with the degradation of NS1 protein and attenuation of viral growth. Conclusions These results indicate that the elongin C binding region of NS1 is crucial for survival of the protein and that disruption of this region results in the degradation of NS1 and restriction of RSV replication.
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Affiliation(s)
- Claire P Straub
- The University of Queensland, Clinical Medical Virology Centre, QLD 4072, Australia
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Discrimination of mumps virus small hydrophobic gene deletion effects from gene translation effects on virus virulence. J Virol 2011; 85:6082-5. [PMID: 21471236 DOI: 10.1128/jvi.02686-10] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Deletion of the small hydrophobic (SH) protein of certain paramyxoviruses has been found to result in attenuation, suggesting that the SH protein is a virulence factor. To investigate the role of the mumps virus (MuV) SH protein in virulence, multiple stop codons were introduced into the open reading frame (ORF) of a MuV molecular clone (r88-1961(SHstop)), preserving genome structure but precluding production of the SH protein. No differences in neurovirulence were seen between the wild-type and the SH(stop) viruses. In contrast, upon deletion of the SH gene, significant neuroattenuation was observed. These data indicate that the MuV SH protein is not a neurovirulence factor and highlight the importance of distinguishing gene deletion effects from protein-specific effects.
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64
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Deletion of the M2-2 gene from avian metapneumovirus subgroup C impairs virus replication and immunogenicity in Turkeys. Virus Genes 2011; 42:339-46. [DOI: 10.1007/s11262-011-0577-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 01/17/2011] [Indexed: 10/18/2022]
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65
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Abstract
At 18,954 nucleotides, the J paramyxovirus (JPV) genome is one of the largest in the family Paramyxoviridae, consisting of eight genes in the order 3'-N-P/V/C-M-F-SH-TM-G-L-5'. To study the function of novel paramyxovirus genes in JPV, a plasmid containing a full-length cDNA clone of the genome of JPV was constructed. In this study, the function of the small hydrophobic (SH) protein of JPV was examined by generating a recombinant JPV lacking the coding sequence of the SH protein (rJPVΔSH). rJPVΔSH was viable and had no growth defect in tissue culture cells. However, more tumor necrosis factor alpha (TNF-α) was produced during rJPVΔSH infection, suggesting that SH plays a role in inhibiting TNF-α production. rJPVΔSH induced more apoptosis in tissue culture cells than rJPV. Virus-induced apoptosis was inhibited by neutralizing antibody against TNF-α, suggesting that TNF-α contributes to JPV-induced apoptosis in vitro. The expression of JPV SH protein inhibited TNF-α-induced NF-κB activation in a reporter gene assay, suggesting that JPV SH protein can inhibit TNF-α signaling in vitro. Furthermore, infection of mice with rJPVΔSH induced more TNF-α expression, indicating that SH plays a role in blocking TNF-α expression in vivo.
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66
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Zhang W, Lockey RF, Mohapatra SS. Respiratory syncytial virus: immunopathology and control. Expert Rev Clin Immunol 2010; 2:169-79. [PMID: 20477096 DOI: 10.1586/1744666x.2.1.169] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Respiratory syncytial virus (RSV) is the primary cause of serious upper and lower respiratory tract infections in infants and children worldwide. RSV infection in infancy may lead to the onset of asthma or other health problems later in life. An effective vaccine is not yet available against RSV infection. Humans respond to RSV infection by mounting an immune response, but the antiviral immunity is incomplete, thus repeat RSV infections continue throughout life. The precise mechanism of RSV-induced infection and immunopathology remains unclear. The limited knowledge of RSV immunity is a major problem in designing a protective vaccine. In this review, the biology of RSV infection, its immunopathology, the role of innate and adaptive immunity, as well as the understanding of how to control RSV infection based on prophylactic and therapeutic approaches are discussed.
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Affiliation(s)
- Weidong Zhang
- Division of Allergy and Immunology, Department of Internal Medicine, College of Medicine, University of South Florida, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA.
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67
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Carter SD, Dent KC, Atkins E, Foster TL, Verow M, Gorny P, Harris M, Hiscox JA, Ranson NA, Griffin S, Barr JN. Direct visualization of the small hydrophobic protein of human respiratory syncytial virus reveals the structural basis for membrane permeability. FEBS Lett 2010; 584:2786-90. [PMID: 20471980 PMCID: PMC2896471 DOI: 10.1016/j.febslet.2010.05.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 04/29/2010] [Accepted: 05/03/2010] [Indexed: 12/02/2022]
Abstract
Human respiratory syncytial virus (HRSV) is the leading cause of lower respiratory tract disease in infants. The HRSV small hydrophobic (SH) protein plays an important role in HRSV pathogenesis, although its mode of action is unclear. Analysis of the ability of SH protein to induce membrane permeability and form homo-oligomers suggests it acts as a viroporin. For the first time, we directly observed functional SH protein using electron microscopy, which revealed SH forms multimeric ring-like objects with a prominent central stained region. Based on current and existing functional data, we propose this region represents the channel that mediates membrane permeability. Structured summary MINT-7890792, MINT-7890805: SH (uniprotkb:P04852) and SH (uniprotkb:P04852) bind (MI:0407) by chromatography technology (MI:0091) MINT-7890784, MINT-7890776: SH (uniprotkb:P04852) and SH (uniprotkb:P04852) bind (MI:0407) by electron microscopy (MI:0040)
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Affiliation(s)
- Stephen D Carter
- Institute for Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
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68
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Respiratory syncytial virus nonstructural proteins decrease levels of multiple members of the cellular interferon pathways. J Virol 2009; 83:9682-93. [PMID: 19625398 DOI: 10.1128/jvi.00715-09] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Viruses of the Paramyxoviridae family, such as the respiratory syncytial virus (RSV), suppress cellular innate immunity represented by type I interferon (IFN) for optimal growth in their hosts. The two unique nonstructural (NS) proteins, NS1 and NS2, of RSV suppress IFN synthesis, as well as IFN function, but their exact targets are still uncharacterized. Here, we investigate if either or both of the NS proteins affect the steady-state levels of key members of the IFN pathway. We found that both NS1 and NS2 decreased the levels of TRAF3, a strategic integrator of multiple IFN-inducing signals, although NS1 was more efficient. Only NS1 reduced IKKepsilon, a key protein kinase that specifically phosphorylates and activates IFN regulatory factor 3. Loss of the TRAF3 and IKKepsilon proteins appeared to involve a nonproteasomal mechanism. Interestingly, NS2 modestly increased IKKepsilon levels. In the IFN response pathway, NS2 decreased the levels of STAT2, the essential transcription factor for IFN-inducible antiviral genes. Preliminary mapping revealed that the C-terminal 10 residues of NS1 were essential for reducing IKKepsilon levels and the C-terminal 10 residues of NS2 were essential for increasing and reducing IKKepsilon and STAT2, respectively. In contrast, deletion of up to 20 residues of the C termini of NS1 and NS2 did not diminish their TRAF3-reducing activity. Coimmunoprecipitation studies revealed that NS1 and NS2 form a heterodimer. Clearly, the NS proteins of RSV, working individually and together, regulate key signaling molecules of both the IFN activation and response pathways.
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69
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Oshansky CM, Zhang W, Moore E, Tripp RA. The host response and molecular pathogenesis associated with respiratory syncytial virus infection. Future Microbiol 2009; 4:279-97. [PMID: 19327115 DOI: 10.2217/fmb.09.1] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Since the isolation of respiratory syncytial virus (RSV) in 1956, its significance as an important human pathogen in infants, the elderly and the immunocompromised has been established. Many important mechanisms contributing to RSV infection, replication and disease pathogenesis have been uncovered; however, there is still insufficient knowledge in these and related areas, which must be addressed to facilitate the development of safe and effective vaccines and therapeutic treatments. A better understanding of the molecular pathogenesis of RSV infection, particularly the host-cell response and transcription profiles to RSV infection, is required to advance disease intervention strategies. Substantial information is accumulating regarding how RSV proteins modulate molecular signaling and regulation of cytokine and chemokine responses to infection, molecular signals regulating programmed cell death, and innate and adaptive immune responses to infection. This review discusses RSV manipulation of the host response to infection and related disease pathogenesis.
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Affiliation(s)
- Christine M Oshansky
- Department of Infectious Diseases, University of Georgia, Athens, GA 30602, USA.
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Ling Z, Tran KC, Teng MN. Human respiratory syncytial virus nonstructural protein NS2 antagonizes the activation of beta interferon transcription by interacting with RIG-I. J Virol 2009; 83:3734-42. [PMID: 19193793 PMCID: PMC2663251 DOI: 10.1128/jvi.02434-08] [Citation(s) in RCA: 169] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Accepted: 01/27/2009] [Indexed: 12/24/2022] Open
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.
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Affiliation(s)
- Zhenhua Ling
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, 406 Althouse, University Park, PA 16802, USA.
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71
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Deletion of nonstructural proteins NS1 and NS2 from pneumonia virus of mice attenuates viral replication and reduces pulmonary cytokine expression and disease. J Virol 2008; 83:1969-80. [PMID: 19052095 DOI: 10.1128/jvi.02041-08] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Pneumonia virus of mice (PVM) strain 15 causes fatal pneumonia in mice and provides a convenient model for human respiratory syncytial virus pathogenesis and immunobiology. We prepared PVM mutants lacking the genes for nonstructural proteins NS1 and/or NS2. In Vero cells, which lack type I interferon (IFN), deletion of these proteins had no effect on the efficiency of virus growth. In IFN-competent mouse embryo fibroblasts, wild-type (wt) PVM and the DeltaNS1 virus grew efficiently and strongly inhibited the IFN response, whereas virus lacking NS2 was highly attenuated and induced high levels of IFN and IFN-inducible genes. In BALB/c mice, intranasal infection with wt PVM caused overt disease that began on day 6 and was lethal by day 9 postinoculation. In comparison, DeltaNS1 induced transient, reduced disease, and DeltaNS2 and DeltaNS12 caused no disease. Thus, NS1 and NS2 are virulence factors, with NS2 being a major antagonist of the type I IFN system. The pulmonary titers of wt PVM and DeltaNS1 were high on day 3 and increased further by day 6; in addition, expression of IFN and representative proinflammatory cytokines/chemokines and T lymphocyte-related cytokines was undetectable on day 3 but increased dramatically by day 6 coincident with the onset of disease. The titers of DeltaNS2 and DeltaNS12 were somewhat lower on day 3 and decreased further by day 6; in addition, these viruses induced a more circumscribed set of cytokines/chemokines (IFN, interleukin-6 [IL-6], and CXCL10) that were detected on day 3 and had largely subsided by day 6. Lung immunohistology revealed abundant PVM-positive pneumocytes and bronchial and bronchiolar epithelial cells in wt PVM- and DeltaNS1-infected mice on day 6 compared to few PVM-positive foci with DeltaNS2 and DeltaNS12. These results indicate that severe PVM disease is associated with high, poorly controlled virus replication driving the expression of high levels of pulmonary IFN and a broad array of cytokines/chemokines. In contrast, in the absence of NS2, there was an early, transient innate response involving moderate levels of IFN, IL-6, and CXCL10 that restricted virus replication and prevented disease.
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72
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Kaur J, Tang R, Spaete R, Schickli J. Optimization of plasmid-only rescue of highly attenuated and temperature-sensitive respiratory syncytial virus (RSV) vaccine candidates for human trials. J Virol Methods 2008; 153:196-202. [DOI: 10.1016/j.jviromet.2008.07.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2008] [Revised: 07/03/2008] [Accepted: 07/17/2008] [Indexed: 11/17/2022]
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Abstract
Respiratory syncytial virus (RSV) is the leading cause of severe respiratory disease in infants and is an important source of morbidity and mortality in the elderly and immunocompromised. This review will discuss the humoral and cellular adaptive immune responses to RSV infection and how these responses are shaped in the immature immune system of the infant and the aged environment of the elderly. Furthermore, we will provide an overview of our current understanding of the role the various arms of the adaptive immune response play in mediating the delicate balance between the successful elimination of the virus from the host and the induction of immunopathology. Efficacious immunization against RSV remains a high priority within the field and we will highlight recent advances made in vaccine design.
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Affiliation(s)
- Matthew R Olson
- Department of Microbiology, 51 Newton Road, 3−532 Bowen Science Building, University of Iowa, Iowa City, IA 52242, USA Tel.: +1 319 335 8433 Fax: +1 319 335 9006
| | - Steven M Varga
- Department of Microbiology, Interdisciplinary Graduate Program in Immunology, 51 Newton Road, 3−532 Bowen Science Building, University of Iowa, Iowa City, IA 52242, USA Tel.: +1 319 335 7784 Fax: +1 319 335 9006
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74
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Nonstructural proteins 1 and 2 of respiratory syncytial virus suppress maturation of human dendritic cells. J Virol 2008; 82:8780-96. [PMID: 18562519 DOI: 10.1128/jvi.00630-08] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Human respiratory syncytial virus (RSV) is the most important agent of serious pediatric respiratory tract disease worldwide. One of the main characteristics of RSV is that it readily reinfects and causes disease throughout life without the need for significant antigenic change. The virus encodes nonstructural protein 1 (NS1) and NS2, which are known to suppress type I interferon (IFN) production and signaling. In the present study, we monitored the maturation of human monocyte-derived myeloid dendritic cells (DC) following inoculation with recombinant RSVs bearing deletions of the NS1 and/or NS2 proteins and expressing enhanced green fluorescent protein. Deletion of the NS1 protein resulted in increased expression of cell surface markers of DC maturation and an increase in the expression of multiple cytokines and chemokines. This effect was enhanced somewhat by further deletion of the NS2 protein, although deletion of NS2 alone did not have a significant effect. The upregulation was largely inhibited by pretreatment with a blocking antibody against the type I IFN receptor, suggesting that suppression of DC maturation by NS1/2 is, at least in part, a result of IFN antagonism mediated by these proteins. Therefore, this study identified another effect of the NS1 and NS2 proteins. The observed suppression of DC maturation may result in decreased antigen presentation and T-lymphocyte activation, leading to incomplete and/or weak immune responses that might contribute to RSV reinfection.
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Ling Z, Tran KC, Arnold JJ, Teng MN. Purification and characterization of recombinant human respiratory syncytial virus nonstructural protein NS1. Protein Expr Purif 2007; 57:261-70. [PMID: 17997327 DOI: 10.1016/j.pep.2007.09.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Revised: 09/18/2007] [Accepted: 09/19/2007] [Indexed: 10/22/2022]
Abstract
We report here the first biochemical and structural characterization of the respiratory syncytial virus (RSV) NS1 protein. We have used a pET-ubiquitin expression system to produce respiratory syncytial virus (RSV) NS1 protein in E. coli that contains a hexahistidine-tag on either the amino- or carboxyl-terminus (His(6)-NS1 and NS1-His(6), respectively). We have been able to isolate milligram quantities of highly purified His(6)-NS1 and NS1-His(6) by nickel affinity chromatography. Generation of recombinant RSV indicated that addition of the hexahistidine tag to the C-terminus of NS1 slightly decreased viral replication competence whereas addition of the tag to the N-terminus had no observable effect. Therefore, we performed a comprehensive biochemical and biophysical characterization on His(6)-NS1. His(6)-NS1 is monodisperse in solution as determined by dynamic light scattering analysis. Both gel filtration and analytical ultracentrifugation showed that His(6)-NS1 is predominantly a monomer. In agreement with theoretical predictions, circular dichroism spectroscopy showed that His(6)-NS1 contains 21% alpha-helices, 34% beta-sheets, and 45% undefined structure. Immunization with purified His(6)-NS1 generated an antiserum that specifically recognizes NS1 by immunoprecipitation from HEp-2 cells infected by RSV, indicating that His(6)-NS1 resembles native NS1. The availability of purified RSV NS1 will permit biochemical and structural investigations providing insight into the function of NS1 in viral replication and interferon antagonism.
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Affiliation(s)
- Zhenhua Ling
- Graduate Program in Biochemistry, Microbiology, and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
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77
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Dibben O, Thorpe LC, Easton AJ. Roles of the PVM M2-1, M2-2 and P gene ORF 2 (P-2) proteins in viral replication. Virus Res 2007; 131:47-53. [PMID: 17881076 DOI: 10.1016/j.virusres.2007.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2007] [Revised: 08/11/2007] [Accepted: 08/12/2007] [Indexed: 10/22/2022]
Abstract
A plasmid-based reverse genetics system for pneumonia virus of mice (PVM) using a synthetic minigenome is described. The system was used to investigate the functions of several viral proteins. The M2-1 protein of PVM was shown to enhance reporter gene expression when present at low levels, similar to the situation for the equivalent respiratory syncytial virus (RSV) M2-1 protein, but at high levels was shown to reduce gene expression from the minigenome activity, which differs significantly form the situation with RSV. Analysis of levels of nucleocapsid complex RNA showed that high levels of the PVM M2-1 protein inhibits RNA replication rather than transcription. In contrast, expression of the PVM M2-2 protein in conjunction with the polymerase proteins in a minigenome assay greatly reduced the levels of CAT reporter protein. This is similar to the situation with the RSV M2-2 protein although there is no significant sequence identity between the M2-2 proteins of the pneumoviruses. A significant difference between the genome organisations of RSV and PVM is that the P gene of PVM contains a second open reading frame, encoding the P-2 protein, which has no counterpart in the RSV P gene. Co-expression of the PVM P-2 protein with the minigenome inhibited virus gene expression. This resembles the situation seen with the accessory proteins expressed from alternate reading frames of the P gene of other paramyxoviruses. Analysis of levels of antigenome RNA and CAT mRNA produced by the minigenome in the presence of the P2 protein indicated that the protein inhibits viral transcription in a dose-dependent fashion.
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Affiliation(s)
- Oliver Dibben
- Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK
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78
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Meyer G, Deplanche M, Schelcher F. Human and bovine respiratory syncytial virus vaccine research and development. Comp Immunol Microbiol Infect Dis 2007; 31:191-225. [PMID: 17720245 DOI: 10.1016/j.cimid.2007.07.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/12/2007] [Indexed: 11/23/2022]
Abstract
Human (HRSV) and bovine (BRSV) respiratory syncytial viruses (RSV) are two closely related viruses, which are the most important causative agents of respiratory tract infections of young children and calves, respectively. BRSV vaccines have been available for nearly 2 decades. They probably have reduced the prevalence of RSV infection but their efficacy needs improvement. In contrast, despite decades of research, there is no currently licensed vaccine for the prevention of HRSV disease. Development of a HRSV vaccine for infants has been hindered by the lack of a relevant animal model that develops disease, the need to immunize immunologically immature young infants, the difficulty for live vaccines to find the right balance between attenuation and immunogenicity, and the risk of vaccine-associated disease. During the past 15 years, intensive research into a HRSV vaccine has yielded vaccine candidates, which have been evaluated in animal models and, for some of them, in clinical trials in humans. Recent formulations have focused on subunit vaccines with specific CD4+ Th-1 immune response-activating adjuvants and on genetically engineered live attenuated vaccines. It is likely that different HRSV vaccines and/or combinations of vaccines used sequentially will be needed for the various populations at risk. This review discusses the recent advances in RSV vaccine development.
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Affiliation(s)
- Gilles Meyer
- INRA-ENVT, UMR1225 IHAP, Interactions Hôtes-Virus et Vaccinologie, Ecole Nationale Vétérinaire, 23 Chemin des Capelles, BP 87614, 31076 Toulouse Cedex, France.
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79
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Elliott MB, Chen T, Terio NB, Chong SY, Abdullah R, Luckay A, Egan MA, Boutilier LA, Melville K, Lerch RA, Long D, Eldridge JH, Parks CL, Udem SA, Hancock GE. Alphavirus replicon particles encoding the fusion or attachment glycoproteins of respiratory syncytial virus elicit protective immune responses in BALB/c mice and functional serum antibodies in rhesus macaques. Vaccine 2007; 25:7132-44. [PMID: 17850933 DOI: 10.1016/j.vaccine.2007.07.065] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Revised: 07/22/2007] [Accepted: 07/24/2007] [Indexed: 11/15/2022]
Abstract
Respiratory syncytial virus (RSV) is a major cause of acute respiratory tract disease in humans. Towards development of a prophylactic vaccine, we genetically engineered Venezuelan equine encephalitis virus (VEEV) replicons encoding the fusion (Fa) or attachment (Ga or Gb) proteins of the A or B subgroups of RSV. Intramuscular immunization with a formulation composed of equal amounts of each replicon particle (3vRSV replicon vaccine) generated serum neutralizing antibodies against A and B strains of RSV in BALB/c mice and rhesus macaques. When contrasted with purified natural protein or formalin-inactivated RSV formulated with alum, the 3vRSV replicon vaccine induced balanced Th1/Th2 T cell responses in mice. This was evident in the increased number of RSV-specific IFN-gamma(+) splenocytes following F or G peptide stimulation, diminished quantity of eosinophils and type 2 T cell cytokines in the lungs after challenge, and increased in vivo lysis of RSV peptide-loaded target cells. The immune responses in mice were also protective against intranasal challenge with RSV. Thus, the replicon-based platform represents a promising new strategy for vaccines against RSV.
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80
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Becker Y. Past, present and future of RSV and PIV vaccines and anti-RSV antibodies for the protection of humans against RSV. Expert Opin Ther Pat 2007. [DOI: 10.1517/13543776.17.8.941] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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81
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Tran KC, He B, Teng MN. Replacement of the respiratory syncytial virus nonstructural proteins NS1 and NS2 by the V protein of parainfluenza virus 5. Virology 2007; 368:73-82. [PMID: 17632199 PMCID: PMC2078599 DOI: 10.1016/j.virol.2007.06.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 04/09/2007] [Accepted: 06/13/2007] [Indexed: 01/18/2023]
Abstract
Paramyxoviruses have been shown to produce proteins that inhibit interferon production and signaling. For human respiratory syncytial virus (RSV), the nonstructural NS1 and NS2 proteins have been shown to have interferon antagonist activity through an unknown mechanism. To understand further the functions of NS1 and NS2, we generated recombinant RSV in which both NS1 and NS2 were replaced by the PIV5 V protein, which has well-characterized IFN antagonist activities (DeltaNS1/2-V). Expression of V was able to partially inhibit IFN responses in DeltaNS1/2-V-infected cells. In addition, the replication kinetics of DeltaNS1/2-V were intermediate between DeltaNS1/2 and wild-type (rA2) in A549 cells. However, expression of V did not affect the ability of DeltaNS1/2-V to activate IRF3 nuclear translocation and IFNbeta transcription. These data indicate that V was able to replace some of the IFN inhibitory functions of the RSV NS1 and NS2 proteins, but also that NS1 and NS2 have functions in viral replication beyond IFN antagonism.
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Affiliation(s)
- Kim C. Tran
- Department of Biochemistry and Molecular Biology, Center for Molecular Immunology and Infectious Diseases, Pennsylvania State University, University Park, PA, 16802
| | - Biao He
- Department of Veterinary and Biomedical Sciences, Center for Molecular Immunology and Infectious Diseases, Pennsylvania State University, University Park, PA, 16802
| | - Michael N. Teng
- Department of Biochemistry and Molecular Biology, Center for Molecular Immunology and Infectious Diseases, Pennsylvania State University, University Park, PA, 16802
- *Corresponding author: Department of Biochemistry and Molecular Biology, Pennsylvania State University, 406 South Frear, University Park, PA 16802, Tel: (814) 863-6996, FAX: (814) 863-7024,
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82
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Fuentes S, Tran KC, Luthra P, Teng MN, He B. Function of the respiratory syncytial virus small hydrophobic protein. J Virol 2007; 81:8361-6. [PMID: 17494063 PMCID: PMC1951288 DOI: 10.1128/jvi.02717-06] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Respiratory syncytial virus (RSV), a member of the Paramyxoviridae family, encodes a small hydrophobic (SH) protein of unknown function. Parainfluenza virus 5 (PIV5), a prototypical paramyxovirus, also encodes an SH protein, which inhibits tumor necrosis factor alpha (TNF-alpha) signaling. In this study, recombinant PIV5 viruses without their own SH but containing RSV SH (from RSV strain A2 or B1) in its place (PIV5DeltaSH-RSV SH) and RSV lacking its own SH (RSVDeltaSH) were generated and analyzed. The results indicate that the SH protein of RSV has a function similar to that of PIV5 SH and that it can inhibit TNF-alpha signaling.
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Affiliation(s)
- Sandra Fuentes
- Center of Molecular Immunology and Infectious Disease, Department of Veterinary and Biomedical Sciences, Pennsylvania State University, 115 Henning Bldg., University Park, PA 16802, USA
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83
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Thomas M, Lu JJ, Chen J, Klibanov AM. Non-viral siRNA delivery to the lung. Adv Drug Deliv Rev 2007; 59:124-33. [PMID: 17459519 PMCID: PMC7103292 DOI: 10.1016/j.addr.2007.03.003] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2006] [Accepted: 03/04/2007] [Indexed: 01/13/2023]
Abstract
SiRNAs exert their biological effect by guiding the degradation of their cognate mRNA sequence, thereby shutting down the corresponding protein production (gene silencing by RNA interference or RNAi). Due to this property, siRNAs are emerging as promising therapeutic agents for the treatment of inherited and acquired diseases, as well as research tools for the elucidation of gene function in both health and disease. Because of their lethality and prevalence, lung diseases have attracted particular attention as targets of siRNA-mediated cures. In addition, lung is accessible to therapeutic agents via multiple routes, e.g., through the nose and the mouth, thus obviating the need for targeting and making it an appealing target for RNAi-based therapeutic strategies. The clinical success of siRNA-mediated interventions critically depends upon the safety and efficacy of the delivery methods and agents. Delivery of siRNAs relevant to lung diseases has been attempted through multiple routes and using various carriers in animal models. This review focuses on the recent progress in non-viral delivery of siRNAs for the treatment of lung diseases, particularly infectious diseases. The rapid progress will put siRNA-based therapeutics on fast track to the clinic.
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Affiliation(s)
- Mini Thomas
- Department of Chemistry and Division of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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84
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van Drunen Littel-van den Hurk S, Mapletoft JW, Arsic N, Kovacs-Nolan J. Immunopathology of RSV infection: prospects for developing vaccines without this complication. Rev Med Virol 2007; 17:5-34. [PMID: 17004293 DOI: 10.1002/rmv.518] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Respiratory syncytial virus is the most important cause of lower respiratory tract infection in infants and young children. RSV clinical disease varies from rhinitis and otitis media to bronchiolitis and pneumonia. An increased incidence of asthma later in life has been associated with the more severe lower respiratory tract infections. Despite its importance as a pathogen, there is no licensed vaccine against RSV. This is due to a number of factors complicating the development of an effective and safe vaccine. The immunity to natural RSV infection is incomplete as re-infections occur in all age groups, which makes it challenging to design a protective vaccine. Second, the primary target population is the newborn infant, which has a relatively immature immune system and maternal antibodies that can interfere with vaccination. Finally, some vaccines have resulted in a predisposition for exacerbated pulmonary disease in infants, which was attributed to an imbalanced Th2-biased immune response, although the exact cause has not been elucidated. This makes it difficult to proceed with vaccine testing in infants. It is likely that an effective and safe vaccine needs to elicit a balanced immune response, including RSV-specific neutralising antibodies, CD8 T-cells, Th1/Th2 CD4 T-cells and preferably secretory IgA. Subunit vaccines formulated with appropriate adjuvants may be adequate for previously exposed individuals. However, intranasally delivered genetically engineered attenuated or vectored vaccines are currently most promising for newborns, as they are expected to induce a balanced immune response similar to that elicited to natural infection and not be subject to interference from maternal antibodies. Maternal vaccination may be the optimal strategy to protect the very young infants.
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MESH Headings
- Adult
- Animals
- Antibody Formation
- Child, Preschool
- Female
- Humans
- Immunity, Active
- Immunity, Cellular
- Immunity, Innate
- Immunity, Maternally-Acquired
- Infant
- Infant, Newborn
- Pregnancy
- Respiratory Syncytial Virus Infections/immunology
- Respiratory Syncytial Virus Infections/prevention & control
- Respiratory Syncytial Virus Vaccines/administration & dosage
- Respiratory Syncytial Virus Vaccines/adverse effects
- Respiratory Syncytial Virus Vaccines/immunology
- Respiratory Syncytial Virus, Human/immunology
- Vaccination/methods
- Vaccination/trends
- Vaccines, Subunit/administration & dosage
- Vaccines, Subunit/immunology
- Vaccines, Synthetic/administration & dosage
- Vaccines, Synthetic/immunology
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85
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Kong X, Zhang W, Lockey RF, Auais A, Piedimonte G, Mohapatra SS. Respiratory syncytial virus infection in Fischer 344 rats is attenuated by short interfering RNA against the RSV-NS1 gene. GENETIC VACCINES AND THERAPY 2007; 5:4. [PMID: 17270047 PMCID: PMC1805440 DOI: 10.1186/1479-0556-5-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Accepted: 02/01/2007] [Indexed: 11/21/2022]
Abstract
Background Respiratory syncytial virus (RSV) causes severe bronchiolitis and is a risk factor for asthma. Since there is no commercially available vaccine against RSV, a short interfering RNA against the RSV-NS1gene (siNS1) was developed and its potential for decreasing RSV infection and infection-associated inflammation in rats was tested. Methods Plasmids encoding siNS1 or an unrelated siRNA were complexed with a chitosan nanoparticle delivery agent and administered intranasally. Control animals received a plasmid for a non-specific siRNA. After expression of the plasmid in lung cells for 24 hours, the rats were intranasally infected with RSV. Results Prophylaxis with siNS1 significantly reduced lung RSV titers and airway hyperreactivity to methacholine challenge compared to the control group. Lung sections from siNS1-treated rats showed a sizable reduction in goblet cell hyperplasia and in lung infiltration by inflammatory cells, both characteristics of asthma. Also, bronchoalveolar lavage samples from siNS1-treated animals had fewer eosinophils. Treatment of rats with siNS1 prior to RSV exposure was effective in reducing virus titers in the lung and in preventing the inflammation and airway hyperresponsiveness associated with the infection that has been linked to development of asthma. Conclusion The use of siNS1 prophylaxis may be an effective method for preventing RSV bronchiolitis and potentially reducing the later development of asthma associated with severe respiratory infections.
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Affiliation(s)
- Xiaoyuan Kong
- University of South Florida College of Medicine, Florida, USA
| | - Weidong Zhang
- University of South Florida College of Medicine, Florida, USA
| | | | - Alexander Auais
- Batchelor Children's Institute, University of Miami, Miami, Florida, USA
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86
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Elliott J, Lynch OT, Suessmuth Y, Qian P, Boyd CR, Burrows JF, Buick R, Stevenson NJ, Touzelet O, Gadina M, Power UF, Johnston JA. Respiratory syncytial virus NS1 protein degrades STAT2 by using the Elongin-Cullin E3 ligase. J Virol 2007; 81:3428-36. [PMID: 17251292 PMCID: PMC1866062 DOI: 10.1128/jvi.02303-06] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Respiratory syncytial virus (RSV) infection causes bronchiolitis and pneumonia in infants. RSV has a linear single-stranded RNA genome encoding 11 proteins, 2 of which are nonstructural (NS1 and NS2). RSV specifically downregulates STAT2 protein expression, thus enabling the virus to evade the host type I interferon response. Degradation of STAT2 requires proteasomal activity and is dependent on the expression of RSV NS1 and NS2 (NS1/2). Here we investigate whether RSV NS proteins can assemble ubiquitin ligase (E3) enzymes to target STAT2 to the proteasome. We demonstrate that NS1 contains elongin C and cullin 2 binding consensus sequences and can interact with elongin C and cullin 2 in vitro; therefore, NS1 has the potential to act as an E3 ligase. By knocking down expression of specific endogenous E3 ligase components using small interfering RNA, NS1/2, or RSV-induced STAT2, degradation is prevented. These results indicate that E3 ligase activity is crucial for the ability of RSV to degrade STAT2. These data may provide the basis for therapeutic intervention against RSV and/or logically designed live attenuated RSV vaccines.
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Affiliation(s)
- Joanne Elliott
- Molecular Immunity, Infection and Immunity Group, Centre for Cancer Research and Cell Biology, Queens University Belfast, Whitla Medical Building, 97 Lisburn Rd., Belfast BT9 7BL, Northern Ireland
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87
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Bitko V, Shulyayeva O, Mazumder B, Musiyenko A, Ramaswamy M, Look DC, Barik S. Nonstructural proteins of respiratory syncytial virus suppress premature apoptosis by an NF-kappaB-dependent, interferon-independent mechanism and facilitate virus growth. J Virol 2006; 81:1786-95. [PMID: 17151097 PMCID: PMC1797585 DOI: 10.1128/jvi.01420-06] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The two nonstructural (NS) proteins NS1 and NS2 of respiratory syncytial virus (RSV) are abundantly expressed in the infected cell but are not packaged in mature progeny virions. We found that both proteins were expressed early in infection, whereas the infected cells underwent apoptosis much later. Coincident with NS protein expression, a number of cellular antiapoptotic factors were expressed or activated at early stages, which included NF-kappaB and phosphorylated forms of protein kinases AKT, phosphoinositide-dependent protein kinase, and glycogen synthase kinase. Using specific short interfering RNAs (siRNAs), we achieved significant knockdown of one or both NS proteins in the infected cell, which resulted in abrogation of the antiapoptotic functions and led to early apoptosis. NS-dependent suppression of apoptosis was observed in Vero cells that are naturally devoid of type I interferons (IFN). The siRNA-based results were confirmed by the use of NS-deleted RSV mutants. Early activation of epidermal growth factor receptor (EGFR) in the RSV-infected cell did not require NS proteins. Premature apoptosis triggered by the loss of NS or by apoptosis-promoting drugs caused a severe reduction of RSV growth. Finally, recombinantly expressed NS1 and NS2, individually and together, reduced apoptosis by tumor necrosis factor alpha, suggesting an intrinsic antiapoptotic property of both. We conclude that the early-expressed nonstructural proteins of RSV boost viral replication by delaying the apoptosis of the infected cell via a novel IFN- and EGFR-independent pathway.
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Affiliation(s)
- Vira Bitko
- Department of Biochemistry and Molecular Biology, University of South Alabama, College of Medicine, 307 University Blvd., Mobile, AL 36688-0002, USA
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88
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Becker Y. Respiratory syncytial virus (RSV) evades the human adaptive immune system by skewing the Th1/Th2 cytokine balance toward increased levels of Th2 cytokines and IgE, markers of allergy--a review. Virus Genes 2006; 33:235-52. [PMID: 16972040 DOI: 10.1007/s11262-006-0064-x] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2006] [Accepted: 05/28/2006] [Indexed: 11/26/2022]
Abstract
Infection of infants in their first year of life, children and elderly people with the respiratory syncytial virus (RSV) endangers the life of the patient. An attempt to develop a formalin-inactivated RSV (FI-RSV) vaccine during the 1960s resulted in an aggravated infection in immunized children, leading to hospitalization, while infection of non-immunized children produced much milder symptoms. The reason for this remained an enigma, one which was gradually solved over the last decade by many researchers who studied the molecular biology of RSV infection of respiratory ciliary cells. Clinical studies of RSV-infected patients indicated increased levels of Th2 cytokines and IgE in the patients' sera, suggesting that an allergy-like condition developed during infection. The biomarkers of allergy caused by endogenous or environmental allergens include a marked increase of the Th2 cytokine IL-4 and IgE non-neutralizing antibodies to the allergen. The way allergens trigger allergy was deciphered recently, and will be discussed later. Studies of RSV infection led to the suggestion that RSV patients suffer from allergy prior to RSV infection, a concept that was later abandoned. Studies on HIV-1 [Y. Becker, Virus Genes 28, 319-331 (2005)] research led me to the hypothesis that since HIV-1 infection induces a marked increase of IL-4 and IgE in serum, an allergy-like condition, the AIDS stage is the result of an allergen motif that is embedded in the shed viral gp120 molecules. It is hypothesized that the viral-soluble G glycoprotein (sG) contains a T cell superantigen (Tsag) that is capable of binding to the V(H)3 domain of IgE/FcepsilonRI(+) hematopoietic cells, basophils, mast cells and monocytes, similar to the case of allergens, and that this aggregation causes these innate system cells to degranulate and release large amounts of Th2 cytokines (IL-4, IL-5, IL-10, IL-13) into the blood. The way these Th2 cytokines skew the Th1/Th2 balance toward Th2 > Th1 will be discussed. The aim of the present review is to base RSV pathogenicity on the numerous very good analyses of the virus genes and to suggest a therapeutic approach to treatment that is directed at preventing the inhibitory effects of Th2 cytokines on the adaptive immune system of the patients, instead of inhibiting RSV replication by antivirals. The review of the molecular research on the role of the viral fusion (F) and attachment (G) glycoproteins of RSV provided information on their role in the virus infection: early in infection the F glycoprotein induces Th1 cells to release the Th1 cytokines IL-2, IL-12 and IFN-gamma to activate precursors CTLs (pCTLs) to become anti-RSV CTLs. The G and sG glycoproteins attach to FKNR1(+) ciliary respiratory epithelial cells as well as directly to eosinophils to the lungs. The sG T cell antigen can also induce the release of large amounts of Th2 cytokines from CD4(+) T cells and from FCepsilonRI(+) mast cells, basophils and monocytes. By comparison to HIV-1 gp120 it is possible to show that in the G and sG proteins the T cell antigen resembles the CD4(+) T cell superantigen (=allergen) domain of HIV-1 gp120 which aggregates with IgE/FCepsilonRI(+) hematopoietic cells. The increased IL-4 level in the serum inhibits the adaptive immune response: IL-4Ralpha(+) Th1 cells stop Th1 cytokine synthesis and IL-4Ralpha(+) B cells stop the synthesis of antiviral IgG and IgA and switch to IgE synthesis. In addition, the hematopoietic cells release histamine and prostaglandin which induce wheezing. The gradual increase of sG molecules creates a gradient of fractalkine (FKN) which directs IL-5-activated eosinophils to the lungs of the patient.
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Affiliation(s)
- Yechiel Becker
- Department of Molecular Virology Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
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89
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Moore ML, Peebles RS. Respiratory syncytial virus disease mechanisms implicated by human, animal model, and in vitro data facilitate vaccine strategies and new therapeutics. Pharmacol Ther 2006; 112:405-24. [PMID: 16820210 DOI: 10.1016/j.pharmthera.2006.04.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Accepted: 04/26/2006] [Indexed: 02/07/2023]
Abstract
Respiratory syncytial virus (RSV) is the leading cause of bronchiolitis, pneumonia, mechanical ventilation, and respiratory failure in infants in the US. No effective post-infection treatments are widely available, and currently there is no vaccine. RSV disease is the result of virus-induced airway damage and complex inflammatory processes. The outcome of infection depends on host and viral genetics. Here, we review disease mechanisms in primary RSV infection that are implicated by clinical studies, in vitro systems, and animal models. Defining RSV disease mechanisms is difficult because there is a wide range of RSV disease phenotypes in humans, and there are disparities in RSV disease phenotypes among the animal models of RSV infection. However, host factors identified by multiple lines of investigation as playing important roles in RSV pathogenesis are providing key insights. A better understanding of RSV molecular biology and RSV pathogenesis is facilitating rational vaccine design strategies and molecular targets for new therapeutics.
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Affiliation(s)
- Martin L Moore
- Department of Medicine, Division of Allergy, Pulmonary and Critical Care Medicine, T-1218 MCN, Vanderbilt University School of Medicine, Nashville, TN 37232-2650, USA
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90
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Barik S, Bitko V. Prospects of RNA interference therapy in respiratory viral diseases: update 2006. Expert Opin Biol Ther 2006; 6:1151-60. [PMID: 17049013 DOI: 10.1517/14712598.6.11.1151] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Respiratory viruses, such as influenza, parainfluenza and respiratory syncytial virus (RSV), claim millions of lives annually. At present, there is no completely effective vaccine or drug against these highly mutable RNA viruses. Passive antibody therapies for RSV, despite their limited application and staggering cost, enjoy a virtual monopoly in a multibillion-dollar global market. Recently, however, pioneering discoveries have launched RNA interference as a novel, nucleic acid-based therapy against viral pathogens. Specifically, small interfering RNAs (siRNAs) offered protection against respiratory syncytial virus, parainfluenza and influenza. siRNA against RSV has entered Phase I clinical trials in humans, and preliminary reports are promising. If appropriately formulated for improved specificity, delivery and pharmacokinetics, siRNAs may indeed become effective antivirals in the clinics of the future. This paper provides an overview of the prospects and hurdles facing the antiviral siRNA drugs, with special emphasis on RSV.
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Affiliation(s)
- Sailen Barik
- University of South Alabama College of Medicine, Department of Biochemistry and Molecular Biology, 307 University Blvd, Mobile, Alabama 36688-0002, USA.
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91
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Xie YY, Zhao XD, Jiang LP, Liu HL, Wang LJ, Fang P, Shen KL, Xie ZD, Wu YP, Yang XQ. Inhibition of respiratory syncytial virus in cultured cells by nucleocapsid gene targeted deoxyribozyme (DNAzyme). Antiviral Res 2006; 71:31-41. [PMID: 16687180 DOI: 10.1016/j.antiviral.2006.02.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2005] [Revised: 02/27/2006] [Accepted: 02/27/2006] [Indexed: 11/18/2022]
Abstract
Respiratory syncytial virus (RSV), which presents the primary cause of bronchiolitis and pneumonia among infants and causes significant morbidity and mortality in immunodeficient patients, remains a health problem worldwide. Unfortunately, an effective vaccine is currently unavailable and pharmacologic treatment needs further optimization for RSV disease. Because RSV is a non-segmented negative-strand RNA virus, it may be sensitive to the genome RNA cleaving by DNAzyme, an artificial nucleic acids molecule with high catalytic capability of cleaving complementary RNA molecules. Thus, RSV-targeted DNAzymes potentially present as a therapeutic candidate of RSV diseases. In this study, DNAzymes targeting the RSV genomic RNA or mRNA were designed and synthesized, one of which (DZn1133) did cleave RSV RNA in vitro, inhibit the transcription and expression of F viral gene, reduce the RSV yield by about 7 logs and protect more than 90% RSV-infected Hep-2 cells from a cytopathic effect at 8 microM. Moreover, 10 wild RSV strains isolated from clinic patients including both subgroups A and B were all suppressed by DZn1133 with greater anti-RSV activity than antisense DNA or ribavirin.
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MESH Headings
- Base Sequence
- Cell Line, Tumor
- Cell Survival/drug effects
- Cytopathogenic Effect, Viral/drug effects
- DNA, Catalytic/chemical synthesis
- DNA, Catalytic/pharmacology
- Dose-Response Relationship, Drug
- Enzyme-Linked Immunosorbent Assay
- Formazans/chemistry
- Humans
- Molecular Sequence Data
- Nucleocapsid Proteins/genetics
- RNA, Messenger/metabolism
- RNA, Viral/metabolism
- Respiratory Syncytial Virus Infections/drug therapy
- Respiratory Syncytial Virus, Human/genetics
- Respiratory Syncytial Virus, Human/physiology
- Tetrazolium Salts/chemistry
- Transcription, Genetic/drug effects
- Viral Matrix Proteins/genetics
- Virus Replication/drug effects
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Affiliation(s)
- Yuan-Yuan Xie
- Division of Immunology, Children's Hospital, Chongqing University of Medical Sciences, China
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92
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Day ND, Branigan PJ, Liu C, Gutshall LL, Luo J, Melero JA, Sarisky RT, Del Vecchio AM. Contribution of cysteine residues in the extracellular domain of the F protein of human respiratory syncytial virus to its function. Virol J 2006; 3:34. [PMID: 16723026 PMCID: PMC1540417 DOI: 10.1186/1743-422x-3-34] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Accepted: 05/24/2006] [Indexed: 11/10/2022] Open
Abstract
The mature F protein of all known isolates of human respiratory syncytial virus (HRSV) contains fifteen absolutely conserved cysteine (C) residues that are highly conserved among the F proteins of other pneumoviruses as well as the paramyxoviruses. To explore the contribution of the cysteines in the extracellular domain to the fusion activity of HRSV F protein, each cysteine was changed to serine. Mutation of cysteines 37, 313, 322, 333, 343, 358, 367, 393, 416, and 439 abolished or greatly reduced cell surface expression suggesting these residues are critical for proper protein folding and transport to the cell surface. As expected, the fusion activity of these mutations was greatly reduced or abolished. Mutation of cysteine residues 212, 382, and 422 had little to no effect upon cell surface expression or fusion activity at 32 degrees C, 37 degrees C, or 39.5 degrees C. Mutation of C37 and C69 in the F2 subunit either abolished or reduced cell surface expression by 75% respectively. None of the mutations displayed a temperature sensitive phenotype.
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Affiliation(s)
- Nicole D Day
- Department of Infectious Diseases Research, Centocor, Inc., 145 King of Prussia Road, Radnor, PA, 19087, USA
| | - Patrick J Branigan
- Department of Infectious Diseases Research, Centocor, Inc., 145 King of Prussia Road, Radnor, PA, 19087, USA
| | - Changbao Liu
- Department of Infectious Diseases Research, Centocor, Inc., 145 King of Prussia Road, Radnor, PA, 19087, USA
| | - Lester L Gutshall
- Department of Infectious Diseases Research, Centocor, Inc., 145 King of Prussia Road, Radnor, PA, 19087, USA
| | - Jianquan Luo
- Department of Structural Biology, Centocor, Inc., 145 King of Prussia Road, Radnor, PA, 19087, USA
| | - José A Melero
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda 28220, Madrid, Spain
| | - Robert T Sarisky
- Department of Infectious Diseases Research, Centocor, Inc., 145 King of Prussia Road, Radnor, PA, 19087, USA
| | - Alfred M Del Vecchio
- Department of Infectious Diseases Research, Centocor, Inc., 145 King of Prussia Road, Radnor, PA, 19087, USA
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93
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Collins PL, Murphy BR. New generation live vaccines against human respiratory syncytial virus designed by reverse genetics. Ann Am Thorac Soc 2006; 2:166-73. [PMID: 16113487 PMCID: PMC2713317 DOI: 10.1513/pats.200501-011aw] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Development of a live pediatric vaccine against human respiratory syncytial virus (RSV) is complicated by the need to immunize young infants and the difficulty in balancing attenuation and immunogenicity. The ability to introduce desired mutations into infectious virus by reverse genetics provides a method for identifying and designing highly defined attenuating mutations. These can be introduced in combinations as desired to achieve gradations of attenuation. Attenuation is based on several strategies: multiple independent temperature-sensitive point mutations in the polymerase, a temperature-sensitive point mutation in a transcription signal, a set of non-temperature-sensitive mutations involving several genes, deletion of a viral RNA synthesis regulatory protein, and deletion of viral IFN alpha/beta antagonists. The genetic stability of the live vaccine can be increased by judicious choice of mutations. The virus also can be engineered to increase the level of expression of the protective antigens. Protective antigens from antigenically distinct RSV strains can be added or swapped to increase the breadth of coverage. Alternatively, the major RSV protective antigens can be expressed from transcription units added to an attenuated parainfluenza vaccine virus, making a bivalent vaccine. This would obviate the difficulties inherent in the fragility and inefficient in vitro growth of RSV, simplifying vaccine design and use.
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Affiliation(s)
- Peter L Collins
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892-8007, USA.
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94
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Marsh GA, Tannock GA. The role of reverse genetics in the development of vaccines against respiratory viruses. Expert Opin Biol Ther 2006; 5:369-80. [PMID: 15833074 PMCID: PMC7105756 DOI: 10.1517/14712598.5.3.369] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Despite their significance, the only available vaccines against respiratory viruses are
those for the prevention of influenza. Attempts have been made to produce vaccines against
other respiratory viruses using traditional techniques, but have met with little success.
Reverse genetics, although still a r-elatively new tool for the manipulation of
negative-strand RNA viruses, has great potential for the preparation of vaccines against
many of the common respiratory viruses. In the preparation of live vaccines, reverse
genetics s-ystems allow the direct modification of the specific regions in the genomes of
negative-stranded RNA viruses concerned with attenuation; the ultimate goal is the
introduction of site-specific mutations through a cDNA intermediate in order to develop
strains with the requisite attenuation, antigenic and growth properties needed in a
vaccine. These techniques can also be used to disarm potentially highly pathogenic
viruses, such as emerging H5N1 avian influenza viruses, in order to facilitate large-scale
preparation of viruses for use in inactivated vaccines under conditions of manufacturing
safety. Before these vaccines become available, residual issues concerned with
intellectual property rights to the technology and its application will need to be
resolved.
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Affiliation(s)
- GA Marsh
- Mount Sinai School of Medicine, Department of
Microbiology, Box 1124, 1 Gustave L. Levy Place, New York, NY 10029, USA
| | - GA Tannock
- RMIT University, Department of Biotechnology and
Environmental Biology, PO Box 71, Bundoora Vic., 3083, Australia .
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95
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Cheng X, Park H, Zhou H, Jin H. Overexpression of the M2-2 protein of respiratory syncytial virus inhibits viral replication. J Virol 2006; 79:13943-52. [PMID: 16254330 PMCID: PMC1280200 DOI: 10.1128/jvi.79.22.13943-13952.2005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The M2-2 protein of respiratory syncytial virus (RSV) is involved in regulation of viral RNA transcription and replication. Encoded by the next-to-last gene of RSV, the M2-2 open reading frame (ORF) overlaps with the upstream M2-1 ORF, suggesting that the production of the M2-2 protein might be tightly regulated during virus replication. To evaluate the effect of M2-2 overexpression on RSV replication, the M2-2 gene was separated from M2-1 by leaving it at the position prior to the M2-1 or moving it to the promoter proximal position as an independent transcriptional unit in the RSV A2 genome. Although recombinant viruses bearing the shuffled M2-2 gene were recovered and expressed higher levels of M2-2, most of these viruses grew poorly in HEp-2 cells. Sequence analysis revealed that various mutations (substitution, insertion, and deletion) occurred in the M2-2 gene, resulting in reduced M2-2 activity as measured by the RSV minigenome system. Further examination of the M2-2 sequence and its function showed that either one of the first two AUG codons located at the 5' end of M2-2 could be used to produce a functional M2-2 protein and that deletion of the first six amino acids from its N terminus or four amino acids from its C terminus greatly reduced its function. The effect of M2-2 protein on RSV replication was also studied by examining RSV replication in cells transiently expressing M2-2. The M2-2 protein expressed at a high level completely inhibited RSV replication. These results strongly suggested that the level of the M2-2 protein produced in the infected cells is critical to RSV replication.
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Affiliation(s)
- Xing Cheng
- MedImmune Vaccines Inc., 297 N. Bernardo Ave., Mountain View, CA 94043, USA
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96
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Ramaswamy M, Shi L, Varga SM, Barik S, Behlke MA, Look DC. Respiratory syncytial virus nonstructural protein 2 specifically inhibits type I interferon signal transduction. Virology 2006; 344:328-39. [PMID: 16216295 DOI: 10.1016/j.virol.2005.09.009] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Revised: 07/05/2005] [Accepted: 09/07/2005] [Indexed: 12/20/2022]
Abstract
Human respiratory syncytial virus (RSV) inhibits type I interferon-induced gene expression by decreasing expression of signal transducer and activator of transcription (Stat)2. To identify the RSV protein that mediates effects on Stat2, airway epithelial cells were infected with vaccinia virus vectors that express single RSV proteins. Expression of RSV nonstructural (NS)2 protein alone was sufficient to decrease Stat2 levels. Furthermore, decreasing RSV NS2 levels using RNA interference in respiratory epithelial cells inhibited the RSV-mediated decrease in Stat2 expression. Airway epithelial cells were also infected with equivalent inoculums of RSV without or with single gene deletions of NS1 or NS2. RSV infection without NS2 expression did not result in decreased Stat2 levels or loss of type I interferon-dependent signaling, indicating that NS2 expression is necessary for RSV effects on Stat2. Taken together, our results indicate that NS2 regulates Stat2 levels during RSV infection, thereby modulating viral effects on interferon-dependent gene expression.
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Affiliation(s)
- Murali Ramaswamy
- Department of Internal Medicine, University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, IA 52242, USA
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97
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Cranage M, Taylor G. Carriers for the delivery of a vaccine against respiratory syncytial virus. Expert Opin Biol Ther 2005; 5:939-52. [PMID: 16018739 DOI: 10.1517/14712598.5.7.939] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Respiratory syncytial virus (RSV) is a major cause of bronchiolitis and pneumonia in young children and the elderly. Despite its clinical importance, there is no licensed vaccine available at present. Vaccine development has been hampered by observations of increased pathology after RSV infection in infants vaccinated with formalin-inactivated RSV; incomplete immunity following natural infection; and the need to be effective during the neonatal period when levels of maternal antibody are high. Four categories of RSV vaccine carriers--live-attenuated RSVs, recombinant vectors expressing the protective antigens of RSV, DNA vaccines and subunit vaccines--have been evaluated in animal models and/or clinical trials. So far, studies with live-attenuated virus vaccines highlight the need to improve immunogenicity whilst maintaining a suitable level of attenuation. Studies with recombinant vectors, DNA and subunit vaccines illustrate the pivotal nature of the vaccine carrier in determining the balance between immune-mediated protection against infection and the induction of immune-mediated pulmonary pathology.
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Affiliation(s)
- Martin Cranage
- Division of Cellular and Molecular Medicine, Centre for Infection, St. George's, University of London, Cranmer Terrace, London, SW17 0RE, UK.
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98
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Branigan PJ, Liu C, Day ND, Gutshall LL, Sarisky RT, Del Vecchio AM. Use of a novel cell-based fusion reporter assay to explore the host range of human respiratory syncytial virus F protein. Virol J 2005; 2:54. [PMID: 16014172 PMCID: PMC1190219 DOI: 10.1186/1743-422x-2-54] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Accepted: 07/13/2005] [Indexed: 01/07/2023] Open
Abstract
Human respiratory syncytial virus (HRSV) is an important respiratory pathogen primarily affecting infants, young children, transplant recipients and the elderly. The F protein is the only virion envelope protein necessary and sufficient for virus replication and fusion of the viral envelope membrane with the target host cell. During natural infection, HRSV replication is limited to respiratory epithelial cells with disseminated infection rarely, if ever, occurring even in immunocompromised patients. However, in vitro infection of multiple human and non-human cell types other than those of pulmonary tract origin has been reported. To better define host cell surface molecules that mediate viral entry and dissect the factors controlling permissivity for HRSV, we explored the host range of HRSV F protein mediated fusion. Using a novel recombinant reporter gene based fusion assay, HRSV F protein was shown to mediate fusion with cells derived from a wide range of vertebrate species including human, feline, equine, canine, bat, rodent, avian, porcine and even amphibian (Xenopus). That finding was extended using a recombinant HRSV engineered to express green fluorescent protein (GFP), to confirm that viral mRNA expression is limited in several cell types. These findings suggest that HRSV F protein interacts with either highly conserved host cell surface molecules or can use multiple mechanisms to enter cells, and that the primary determinants of HRSV host range are at steps post-entry.
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Affiliation(s)
- Patrick J Branigan
- Infectious Diseases Research, Centocor, Inc., 145 King of Prussia Road, Radnor, PA, 19087, USA
| | - Changbao Liu
- Infectious Diseases Research, Centocor, Inc., 145 King of Prussia Road, Radnor, PA, 19087, USA
| | - Nicole D Day
- Infectious Diseases Research, Centocor, Inc., 145 King of Prussia Road, Radnor, PA, 19087, USA
| | - Lester L Gutshall
- Infectious Diseases Research, Centocor, Inc., 145 King of Prussia Road, Radnor, PA, 19087, USA
| | - Robert T Sarisky
- Infectious Diseases Research, Centocor, Inc., 145 King of Prussia Road, Radnor, PA, 19087, USA
| | - Alfred M Del Vecchio
- Infectious Diseases Research, Centocor, Inc., 145 King of Prussia Road, Radnor, PA, 19087, USA
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99
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Spann KM, Tran KC, Collins PL. Effects of nonstructural proteins NS1 and NS2 of human respiratory syncytial virus on interferon regulatory factor 3, NF-kappaB, and proinflammatory cytokines. J Virol 2005; 79:5353-62. [PMID: 15827150 PMCID: PMC1082743 DOI: 10.1128/jvi.79.9.5353-5362.2005] [Citation(s) in RCA: 215] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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-alpha/beta) in A549 cells and human macrophages. Two principal transcription factors for the early IFN-beta and -alpha1 response are interferon regulatory factor 3 (IRF-3) and nuclear factor kappaB (NF-kappaB). 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-alpha/beta, NF-kappaB activation was evaluated in Vero cells, which lack the structural genes for IFN-alpha/beta and would preclude confounding effects of IFN-alpha/beta. This showed that deletion of the NS2 gene sharply reduced the ability of HRSV to induce activation of NF-kappaB. 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-alpha/beta 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.
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Affiliation(s)
- Kirsten M Spann
- Laboratory of Infectious Diseases, NIAID, Building 50, Room 6503, 50 South Dr., MSC 8007, Bethesda, MD 20892-8007, USA
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100
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Gould PS, Easton AJ. Coupled translation of the respiratory syncytial virus M2 open reading frames requires upstream sequences. J Biol Chem 2005; 280:21972-80. [PMID: 15784616 DOI: 10.1074/jbc.m502276200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have investigated the mechanism of the translation of the second open reading frame (ORF) of the respiratory syncytial virus M2 transcript that uses a novel coupled translation process requiring prior translation of the upstream ORF. The second M2-2 ORF sequences play no role in the coupling process and can be replaced with other gene sequences. Surprisingly, the overlap region of the two ORFs alone was not sufficient for coupled translation to occur. An analysis of the sequences required for the coupling process showed that portions of the transcript located along the length of the first ORF M2-1, upstream of the ORF overlap region, were essential for coupled translation to occur. A critically important region for this process was centered approximately 150 nucleotides upstream of the ORF2 initiation codons. This region was shown to contain a significant degree of secondary structure, and mutation of this sequence to remove predicted areas of base pairing significantly reduced coupled translation, confirming that the secondary structure was important for the coupling process. Additional sequences further upstream increased the efficiency of the coupled translation process. These data indicate that upstream sequences act in conjunction with the M2-1/M2-2 overlap region to promote coupled translation.
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Affiliation(s)
- Phillip S Gould
- Department of Biological Sciences, The University of Warwick, Gibbet Hill Road, Coventry, Warwick, West Midlands CV4 7AL, United Kingdom
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