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Journal of Virology Jan 1995Defective particles are naturally occurring virus mutants that lack one or more genes required for viral replication. Such viruses may affect positively or negatively...
Defective particles are naturally occurring virus mutants that lack one or more genes required for viral replication. Such viruses may affect positively or negatively the symptoms of the disease. Thus, it is of great interest to measure the role played by defective particles in the process of human immunodeficiency virus (HIV) infection since accumulating evidence indicates that a great proportion of HIV genomes are defective. We used defective particles produced by two stable cellular clones (UHC-8 and UHC-18) to investigate whether they can affect replication of infectious viral particles generated by a human T-cell line transfected with a molecular HIV-1 clone. Progeny virus harvested from UHC-8 cells has no reverse transcriptase and integrase proteins, while UHC-18 has no reverse transcriptase protein. We demonstrate here that coinoculation of a T-lymphoid cell line and of peripheral blood mononuclear cells with defective and infectious particles leads to a dramatic inhibition of virus replication. Defective particles do not interfere with virus production from proviral DNA. Rather, the inhibition of reinfection events seems to be their mechanism of action. This model closely parallels the in vivo conditions and demonstrates that defective particles may limit the spread of infection and progression of the disease by reducing the yield of infectious virus.
Topics: CD4 Antigens; Cell Division; Cell Line; Defective Viruses; HIV-1; Humans; Viral Interference; Virion; Virus Replication
PubMed: 7983721
DOI: 10.1128/JVI.69.1.291-300.1995 -
Journal of Virology Jun 2001Panicum mosaic virus (PMV) is a recently molecularly characterized RNA virus with the unique feature of supporting the replication of two subviral RNAs in a few species...
Panicum mosaic virus (PMV) is a recently molecularly characterized RNA virus with the unique feature of supporting the replication of two subviral RNAs in a few species of the family Gramineae. The subviral agents include a satellite RNA (satRNA) that is devoid of a coding region and the unrelated satellite panicum mosaic virus (SPMV) that encodes its own capsid protein. Here we report the association of this complex with a new entity in the RNA world, a defective-interfering RNA (DI) of a satellite virus. The specificity of interactions governing this four-component viral system is illustrated by the ability of the SPMV DIs to strongly interfere with the accumulation of the parental SPMV. The SPMV DIs do not interfere with PMV satRNA, but they do slightly enhance the rate of spread and titer of PMV. The SPMV-derived DIs provide an additional avenue by which to investigate fundamental biological questions, including the evolution and interactions of infectious RNAs.
Topics: Defective Viruses; Genome, Viral; Molecular Sequence Data; Mutation; Panicum; Satellite Viruses; Tombusviridae; Virus Replication
PubMed: 11333930
DOI: 10.1128/JVI.75.11.5429-5432.2001 -
PloS One 2013Influenza viruses are a major public health burden during seasonal epidemics and a continuous threat due to their potential to cause pandemics. Annual vaccination...
Influenza viruses are a major public health burden during seasonal epidemics and a continuous threat due to their potential to cause pandemics. Annual vaccination provides the best protection against the contagious respiratory illness caused by influenza viruses. However, the current production capacities for influenza vaccines are insufficient to meet the increasing demands. We explored the possibility to establish a continuous production process for influenza viruses using the duck-derived suspension cell line AGE1.CR. A two-stage bioreactor setup was designed in which cells were cultivated in a first stirred tank reactor where an almost constant cell concentration was maintained. Cells were then constantly fed to a second bioreactor where virus infection and replication took place. Using this two-stage reactor system, it was possible to continuously produce influenza viruses. Surprisingly, virus titers showed a periodic increase and decrease during the run-time of 17 days. These titer fluctuations were caused by the presence of defective interfering particles (DIPs), which we detected by PCR. Mathematical modeling confirmed this observation showing that constant virus titers can only emerge in the absence of DIPs. Even with very low amounts of DIPs in the seed virus and very low rates for de novo DIP generation, defective viruses rapidly accumulate and, therefore, represent a serious challenge for continuous vaccine production. Yet, the continuous replication of influenza virus using a two-stage bioreactor setup is a novel tool to study aspects of viral evolution and the impact of DIPs.
Topics: Animals; Bioreactors; Cell Line; Defective Viruses; Ducks; Genome, Viral; Humans; Influenza A Virus, H1N1 Subtype; Influenza Vaccines; Models, Biological; Viral Load; Virus Cultivation; Virus Replication
PubMed: 24039749
DOI: 10.1371/journal.pone.0072288 -
Archives of Virology 1986A novel type of interfering influenza B virus which is defective in the function of M gene has been reported. Clone 301, a B type virus clone obtained by successive...
A novel type of interfering influenza B virus which is defective in the function of M gene has been reported. Clone 301, a B type virus clone obtained by successive back-crosses of A/Aichi/2/68 (H 3 N 2) with B/Yamagata/1/73, grew normally in MDCK cells when inoculated at a low multiplicity, but was easily converted to a hemagglutinating but non-infectious form by one cycle of high multiplicity infection. Within MDCK cells infected with infectious clone 301 at a high multiplicity, synthesis of M protein was greatly reduced. The virus particle produced by a high multiplicity infection was devoid of RNA segment 7 (M gene), contained less amount of M protein compared with the standard virus, and interfered with the replication of wild type B/Yamagata, again accompanied by a selective suppression of M protein synthesis within the co-infected cells.
Topics: Defective Viruses; Genes, Viral; Influenza B virus; Microscopy, Electron; Molecular Weight; Mutation; RNA, Viral; Viral Interference; Viral Proteins
PubMed: 3729727
DOI: 10.1007/BF01317372 -
PLoS Computational Biology Oct 2023Defective interfering particles (DIPs) are virus-like particles that occur naturally during virus infections. These particles are defective, lacking essential genetic...
Defective interfering particles (DIPs) are virus-like particles that occur naturally during virus infections. These particles are defective, lacking essential genetic materials for replication, but they can interact with the wild-type virus and potentially be used as therapeutic agents. However, the effect of DIPs on infection spread is still unclear due to complicated stochastic effects and nonlinear spatial dynamics. In this work, we develop a model with a new hybrid method to study the spatial-temporal dynamics of viruses and DIPs co-infections within hosts. We present two different scenarios of virus production and compare the results from deterministic and stochastic models to demonstrate how the stochastic effect is involved in the spatial dynamics of virus transmission. We compare the spread features of the virus in simulations and experiments, including the formation and the speed of virus spread and the emergence of stochastic patchy patterns of virus distribution. Our simulations simultaneously capture observed spatial spread features in the experimental data, including the spread rate of the virus and its patchiness. The results demonstrate that DIPs can slow down the growth of virus particles and make the spread of the virus more patchy.
Topics: Defective Viruses; Defective Interfering Viruses; Virus Replication; Virion
PubMed: 37782667
DOI: 10.1371/journal.pcbi.1011513 -
Virology Sep 2004A yellow fever (YFV) 17D virus variant, which causes persistent infection of mouse neuroblastoma cells associated with defective cell penetration and small plaque size,...
A yellow fever (YFV) 17D virus variant, which causes persistent infection of mouse neuroblastoma cells associated with defective cell penetration and small plaque size, yielded plaque-revertant viruses from cells transfected with viral transcripts encoding the adaptive mutation (Gly360 in the E protein). Reconstruction of a plaque-purified revertant which contained Gly360 and additional substitutions (Asn for Lys303 and Val for Ala261) yielded a virus whose infectious center size, growth efficiency, and cell penetration rate similar to the parental YF5.2iv virus, whereas viruses with Asn303 or Val261 alone with Gly360 yielded either a small-plaque virus or a parental revertant. These data indicate that the YFV E protein is subject to suppression of mutations in domain III that are deleterious for viral entry and spread by a second-site mutation in domain II. Position 261 lies within the hydrophobic ligand-binding pocket at the domain I-II interface, a site believed to be involved in the hinge-like conformational change of domain II during activation of membrane fusion-activity. Results of this study provide genetic data consistent with findings on flavivirus structure and implicate domain III in functions beyond simply cell surface attachment.
Topics: Amino Acid Sequence; Animals; Chlorocebus aethiops; Defective Viruses; Models, Molecular; Molecular Sequence Data; Mutation; Suppression, Genetic; Vero Cells; Viral Envelope Proteins; Viral Plaque Assay; Yellow fever virus
PubMed: 15327896
DOI: 10.1016/j.virol.2004.06.015 -
Scientific Reports Nov 2016RNA recombination in non-segmented RNA viruses is important for viral evolution and documented for several virus species through in vitro studies. Here we confirm viral...
RNA recombination in non-segmented RNA viruses is important for viral evolution and documented for several virus species through in vitro studies. Here we confirm viral RNA recombination in vivo using an alphavirus, the SAV3 subtype of Salmon pancreas disease virus. The virus causes pancreas disease in Atlantic salmon and heavy losses in European salmonid aquaculture. Atlantic salmon were injected with a SAV3 6K-gene deleted cDNA plasmid, encoding a non-viable variant of SAV3, together with a helper cDNA plasmid encoding structural proteins and 6K only. Later, SAV3-specific RNA was detected and recombination of viral RNA was confirmed. Virus was grown from plasmid-injected fish and shown to infect and cause pathology in salmon. Subsequent cloning of PCR products confirming recombination, documented imprecise homologous recombination creating RNA deletion variants in fish injected with cDNA plasmid, corresponding with deletion variants previously found in SAV3 from the field. This is the first experimental documentation of alphavirus RNA recombination in an animal model and provides new insight into the production of defective virus RNA.
Topics: Alphavirus; Animals; Cell Line; Defective Viruses; Models, Animal; Oncorhynchus keta; Plasmids; RNA, Viral; Recombination, Genetic; Sequence Deletion
PubMed: 27805034
DOI: 10.1038/srep36317 -
Journal of Virology Nov 1996Molecular characterization of bovine viral diarrhea virus pair 13 revealed that isolate CP13 is composed of a cytopathogenic (cp) defective interfering particle (DI13)...
Molecular characterization of bovine viral diarrhea virus pair 13 revealed that isolate CP13 is composed of a cytopathogenic (cp) defective interfering particle (DI13) and a noncytopathogenic (noncp) helper virus. The DI13 genome possesses two internal deletions of 1,611 and 3,102 nucleotides. Except for a small fragment of the gene coding for glycoprotein E1, all structural protein genes are deleted together with most of the Npro gene, the region coding for nonstructural proteins p7 and NS2. While the amino terminus of NS3 seems to be strictly conserved for all other cp bovine viral diarrhea viruses, NS3 of DI13 is amino-terminally truncated and fused to 23 amino acids derived from Npro and E1. Characterization of the DI-helper virus system revealed a striking discrepancy between RNA production and generation of infectious viruses.
Topics: Animals; Cattle; Cytopathogenic Effect, Viral; Defective Viruses; Diarrhea Viruses, Bovine Viral; Gene Deletion; Genome, Viral; Helper Viruses; Viral Proteins
PubMed: 8892949
DOI: 10.1128/JVI.70.11.8175-8181.1996 -
Vaccine Mar 2011Respiratory viruses represent a major clinical burden. Few vaccines and antivirals are available, and the rapid appearance of resistant viruses is a cause for concern....
Respiratory viruses represent a major clinical burden. Few vaccines and antivirals are available, and the rapid appearance of resistant viruses is a cause for concern. We have developed a novel approach which exploits defective viruses (defective interfering (DI) or protecting viruses). These are naturally occurring deletion mutants which are replication-deficient and multiply only when coinfection with a genetically compatible infectious virus provides missing function(s) in trans. Interference/protection is believed to result primarily from genome competition and is therefore usually confined to the virus from which the DI genome originated. Using intranasally administered protecting influenza A virus we have successfully protected mice from lethal in vivo infection with influenza A viruses from several different subtypes [1]. Here we report, contrary to expectation, that protecting influenza A virus also protects in vivo against a genetically unrelated respiratory virus, pneumonia virus of mice, a pneumovirus from the family Paramyxoviridae. A single dose that contains 1μg of protecting virus protected against lethal infection. This protection is achieved by stimulating type I interferon and possibly other elements of innate immunity. Protecting virus thus has the potential to protect against all interferon-sensitive respiratory viruses and all influenza A viruses.
Topics: Animals; Defective Viruses; Humans; Influenza A virus; Interferon Type I; Mice; Murine pneumonia virus; Orthomyxoviridae Infections; Pneumovirus Infections; Respiratory Tract Infections; Survival Analysis
PubMed: 21320545
DOI: 10.1016/j.vaccine.2011.01.102 -
Current Topics in Microbiology and... 1981
Review
Topics: Base Sequence; DNA Viruses; Defective Viruses; Genes, Viral; Models, Biological; Nucleic Acid Conformation; Protein Biosynthesis; RNA Viruses; RNA, Viral; RNA-Dependent RNA Polymerase; Transcription, Genetic; Viral Interference; Virus Replication
PubMed: 7026180
DOI: 10.1007/978-3-642-68123-3_7