Defective Interfering Animal Viruses

SUMMARYWe describe a simple, rapid and reproducible assay for defective-interfering Semliki Forest virus (DI SFV) which is based on the inhibition of synthesis of virus-specified RNAs in SFV-infected cells. Using the assay, we have been able to show that DI virus is generated by a single passage in baby hamster kidney (BHK) cells in an inoculum which contained no detectable DI virus and we have calculated the u.v. target size of the interfering activity.

Section: Introductionmentioning

confidence: 99%

Assay of Defective-interfering Semliki Forest Virus by the Inhibition of Synthesis of Virus-specified RNAs

Barrett

Crouch

Dimmock

1981

“…A comparison of the yield of infectious progeny virus (1 × 107 p.f.u./ml) to that of cultures infected with ST virus alone (1-5 x 108 p.f.u./ml) indicates the presence of interfering virus particles in the HP4 virus stock. The fact that consecutive infection with standard virus followed by HP4 resulted in interference characterizes this type of interference as homologous intracellular interference (Huang & Baltimore, 1977), i.e. an intracellular process rather than competition for receptor sites.…”

Section: Infectivity Of Virus Dna Synthesized Upon Infection Under Inmentioning

confidence: 99%

Low Infectivity of HSV-1 DNA Caused by Defective-interfering Genomes

Hennes-Stegmann

Schröder

1982

SUMMARYThe infectivity of herpes simplex virus, type 1, strain ANG progeny DNA from standard virus infections and of progeny DNA from infections involving defectiveinterfering virus particles (DI DNA) was compared in transfection assays. No difference in infectivity of virus DNA isolated either from infected cells or from progeny virus was found for a given type of infection. However, the values for the two types of infection differed markedly, with DI progeny DNA being less infectious by more than 2 log10. The low infectivity was mainly due to the presence of interfering DNA molecules in DI progeny DNA, regardless of whether intracellular DNA or DNA extracted from mature virions was analysed. The interfering capacity of DI progeny DNA did not depend on the integrity of the genomes. The physical proximity provided by simultaneous precipitation of infectious and of interfering DNA is an important factor influencing the degree to which DI DNA interferes. Interference by DI DNA in the transfection assay can be partly reversed by the addition of XbaI fragments of standard DNA; in control experiments this fragmented DNA was shown to lead to a reduction rather than to an enhancement of the infectivity of standard virus DNA.

“…This attenuation often follows the generation of defective interfering particles (DIP) (Huang & Baltimore, 1977). DIP have the same protein components as the standard virus, require the presence of standard virus for replication and interfere with the replication of the standard virus (Huang, 1973).…”

Section: Introductionmentioning

confidence: 99%

“…The generation of DIP of vesicular stomatitis virus, the type member of the rhabdovirus group, has been well studied (Huang & Baltimore, 1977). Short particles accumulate following repeated passage of the virus at high multiplicities of infection.…”

Section: Introductionmentioning

confidence: 99%

Isolation of Defective Interfering Particles of Sonchus Yellow Net Virus from Chronically Infected Plants

Ismail

Milner

1988

SUMMARYNicotiana edwardsonii plants were examined by electron microscopy 5 months after inoculation with Sonchus yellow net virus (SYNV). No virions were observed in leaf or root cells, but cells in sections of calyx tissue contained large numbers of virus particles. Most of these particles were only 73 to 86 ~ as tong as particles of standard SYNV. Nicotiana edwardsonii inoculated with sap extracted from chronically infected calyx became systemically infected but exhibited chlorotic mottling, instead of the normal vein-clearing symptoms. Most virus particles in these plants were short, and when purified, sedimented more slowly than standard SYNV. Purified short particles were not infective, but plants inoculated with a mixture of short and standard particles developed mottling symptoms and yielded predominantly short particles. Proteins from short particles were electrophoretically and antigenically identical to those from standard virus. RNA from short particles was 77~ the size of RNA from standard SYNV and hybridized to cloned SYNV cDNA. These short particles have all the characteristics of defective interfering particles.