Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “VIRAL INTERFERENCE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 991 records · Page 55Linked to original sources
PubMed2001

[Effects of attenuated measles virus on hepatitis B virus in vivo and in vitro].

OBJECTIVE: To observe the effects of attenuated measles virus on hepatitis B virus replication inside and outside the body. METHODS: Patients with chronic hepatitis B virus replication were chosen, and attenuated measles viruses were inoculated in them and observed twice every week for a total of 48 weeks. The changes of CD4+, CD8+, IFN-gamma, IL-2, HBeAg and HBV DAN were observed. Also the changes of the HBVM were observed when adding the measles virus in suspension of the 2.2.15 cells. RESULTS: The average ratio of CD4+ and CD8+ before the treatment was 1.05 +/- 0.19 and it rose to 1.47 +/- 0.18 after follow up for 48 weeks. Then, compared with the ratio before the treatment, the difference was significant(t = 5.36, P < 0.01). After inoculating the measles virus for two weeks, IFN-gamma and IL-2 increased. Although the total average ratio had not great difference, IL-2 level of 26.3% of the cases elevated 5 times higher in the second week, as compared with the control group, there was a great difference (chi 2 = 12.07, P < 0.005). The results of the examination of the HBeAg before treatment was 317, 35 +/- 151.75, but became 139.17 +/- 166.66 after observing for 48 weeks(t = 2.16, P < 0.05). The positive ratio of HBV DNA before the treatment was 100% and become 63.16% after treatment. Thus the ratio difference is significant(chi 2 = 10.08, P < 0.005). However, no such ratio difference was found in the control group. When adding the attenuated measles virus in suspension of 2.2.15 cell, the HBsAg and HBeAg decreased. CONCLUSION: When the measles virus and hepatitis B virus infect the cases in an overlapping way, the latter may be interfered by change of the cell immunity status of the body of the former, and measles virus may have direct interference effects on hepatitis B virus.

Adult↗
PubMedDate not supplied

[Pathogenesis and induced virus resistance in tobacco plants affected by tomato spotted wilt virus].

Pathogenecity and virulence of tomato spotted wilt virus isolated from tobacco were studied under the field conditions of the Crimea in the tobacco plants of Immunny 580 variety and Datura stramonium. As to their virulence the obtained 26 isolates were divided into three groups: strongly virulent (severe), middle-virulent and weakly virulent ("mosaic"). It has been shown that strongly virulent isolates interfere with weakly virulent ones and induce the development of nonspecific resistance in tobacco plants, this resistance is also efficient to the tobacco mosaic virus.

Datura stramonium↗
PubMed1984

Mechanism of persistence with canine distemper virus: difference between a laboratory strain and an isolate from a dog with chronic neurological disease.

The mechanism of persistence in culture was different with canine distemper virus (CDV) isolated from a dog with chronic neurological disease (ODE; old dog encephalitis) compared to a laboratory strain (CDV/Ond). CDV/Ond persistence was achieved after seven undiluted passages while CDV/ODE-8, the recent isolate, showed immediate persistence in Vero cells. Both persistent infections resisted challenge with lytic CDV/Ond but not with unrelated vesicular stomatitis virus. The medium from CDV/Ond infection showed interference, whereas the medium from CDV/ODE-8 infection did not. Ultracentrifugation of the CDV/Ond supernatant effectively removed the defective interfering (DI) particles. Fluorescent microscopy showed the presence of CDV antigen in the cytoplasm of both types of persistently infected cells. By electron microscopy, 1% of the CDV/Ond cells and 23% of the CDV/ODE-8 cells showed distemper viral nucleocapsids. Persistence of CDV/Ond appears to be due to classical DI particles, whereas persistence of CDV/ODE-8 appears to be due to cell-associated particles. The persistence of CDV in dogs with ODE may be due to this cell-associated phenomenon.

Animals↗
PubMed2003

Short interfering RNA-mediated interference of gene expression and viral DNA accumulation in cultured plant cells.

Gene silencing mediated by double-stranded RNA is a sequence-specific RNA degradation mechanism highly conserved in eukaryotes that serves as an antiviral defense pathway in both plants and Drosophila. Short interfering RNAs (siRNAs), the 21- to 23-nt double-stranded intermediates of this natural defense mechanism, are becoming powerful tools for reducing gene expression and countering viral infection in a variety of mammalian cells. Here we report the use of siRNAs to target reporter gene expression and viral DNA accumulation in cultured plant cells. Transient expression of reporter genes encoding either GFP or red fluorescent protein from Discosoma was specifically reduced by 58% and 47%, respectively, at 24 h after codelivery of cognate siRNAs in BY2 protoplasts. In contrast to mammalian systems, the siRNA-induced silencing of GFP expression was transitive as indicated by the presence of siRNAs representing parts of the target RNA outside the region homologous to the triggering siRNA. Codelivery of an siRNA designed to target the mRNA encoding the replication-associated protein (AC1) of the geminivirus African cassava mosaic virus (ACMV) from Cameroon blocked AC1 mRNA accumulation by approximately 91% and inhibited accumulation of the ACMV genomic DNA by approximately 66% at 36 and 48 h after transfection. As with siRNA-induced reporter gene silencing, the siRNA targeting ACMV AC1 was specific and did not affect the replication of East African cassava mosaic Cameroon virus. This report demonstrates the occurrence of siRNA-mediated suppression of gene expression in cultured plant cells and that siRNA can interfere with and suppress accumulation of a nuclear-replicated DNA virus.

Base Sequence↗
PubMed1992

Herpes simplex virus type 1 (HSV-1) HSZP interferes also after antibody neutralization with early shutoff of host protein synthesis induced by HSV-1 KOS.

The HSZP strain of herpes simplex virus type 1 (HSV-1) is defective with respect to the early shutoff of host protein synthesis. However, in superinfection experiments using Vero cells, the HSZP strain was effective, even after neutralization by antibody, at interfering with the early shutoff function of the HSV-1 KOS strain. Evidence was given that the observed interference was not due to exclusion of the KOS by HSZP at the level of adsorption or penetration. The neutralized KOS strain failed to induce early shutoff of host protein synthesis.

Animals↗
PubMed2001

Mus cervicolor murine leukemia virus isolate M813 belongs to a unique receptor interference group.

Murine leukemia virus (MuLV) M813 was originally isolated from the Southeast Asian rodent Mus cervicolor. As with the ecotropic MuLVs derived from Mus musculus, its host range is limited to rodent cells. Earlier studies have mapped its receptor to chromosome 2, but it has not been established whether M813 shares a common receptor with any other MuLVs. In this study, we have performed interference assays with M813 and viruses from four interference groups of MuLV. The infection efficiency of M813 was not compromised in cells expressing any one of the other MuLVs, demonstrating that M813 must use a distinct receptor for cell entry. The entire M813 env coding region was molecularly cloned. Sequence analysis revealed high similarity with other MuLVs but with a unique receptor-binding domain. Substitution of M813 env sequences in Moloney MuLV resulted in a replication-competent virus with a host range and interference profile similar to those of the biological clone M813. M813 thus defines a novel receptor interference group of type C MuLVs.

3T3 Cells↗
PubMed2004

Novel treatment options for hepatitis B virus infection.

Chronic hepatitis B virus (HBV) infection affects between 350 and 400 million people globally. Interferon-alpha, lamivudine and adefovir (Hepsera) are approved for the treatment of chronic hepatitis B; however, the use of interferon-alpha is limited. Lamivudine and adefovir have excellent antiviral activity and oral bioavailability, although viral rebound after cessation of therapy and development of resistance after long-term therapy with lamivudine are major clinical limitations. Adefovir has proven to be effective against lamivudine-resistant strains in vitro and in vivo. The various steps of HBV replication provide opportunities for new antiviral drugs to interact with the virus. Recent developments, including new antivirals that interfere with viral DNA replication, hold promise for the future. Sustained reduction in viral load and improved treatment of chronic HBV infection could, in future, be achieved by the development of new drugs with different mechanisms of action and resistance profiles, and with combination therapy involving two or more nucleosides with or without immunomodulators.

Animals↗
PubMed1984

Rubella virus-induced interference in chick embryo cells.

Primary chick embryo cells inoculated with rubella virus were found to develop interference with the multiplication of Sindbis virus. Substantial quantities of interferon (IFN) were detectable in the cell cultures indicating that the resistance induced was due to IFN production.

Animals↗
PubMed1989

Construction and properties of replication-competent murine retroviral vectors encoding methotrexate resistance.

A series of replication-competent Moloney murine leukemia virus vectors was constructed in which each vector contained a mutant dihydrofolate reductase (DHFR) cDNA insert in the U3 region of the viral long terminal repeat. Two of the resulting viruses, MLV (murine leukemia virus) DHFR*-5 and MLV DHFR*-7, were able to stably transfer methotrexate resistance to infected fibroblast cells upon multiple rounds of virus replication and in the absence of drug selection. Cell lines producing recombinant virus with high titers were established, which indicated that the insert did not grossly interfere with viral replication functions. These vectors should be useful for introducing and expressing foreign genes in vivo in tissues and whole animals in which virus spread is needed for efficient infection.

Animals↗
PubMed1983

Properties of DI particle resistant mutants of vesicular stomatitis virus isolated from persistent infections and from undiluted passages.

We describe an assay procedure to quantitate relative DI resistance of a variety of DI particle resistant (Sdi-) mutants of vesicular stomatitis virus (VSV). We show that numerous diverse Sdi- mutants of VSV are selected continuously in a stepwise manner during persistent infections, and also during serial undiluted lytic passages initiated with cloned virus. Concurrently with the successive appearance and disappearance of different Sdi- mutants of infectious VSV, new DI particle types with altered interference properties also appear and disappear, resulting in rapid "coevolution" of virus and DI particle populations. Complementation tests with Sdi- mutants indicate that mutations in at least two different virus factors (presumably associated with replication-encapsidation) can give rise to Sdi- mutants. Interference studies with chimeric DI particles indicate that DI particle template RNA rather than DI particle protein determines the interference properties of DI particles interacting with Sdi- and Sdi+ mutants of helper virus.

Defective Viruses↗
PubMed1997

Interference activity of bovine herpes virus 1 strains against Aujeszky's disease virus in cell cultures.

The interference-inducing activity of different low- and high-virulence strains of bovine herpes virus 1 (BHV-1) against Aujeszky's disease virus was studied by a parallel titration on permissive and non-permissive cell culture. The low-virulence BHV-1 strains possessed better interference-inducing activity than the high-virulence strains. An interference blocking test (IBT) was developed for the detection of BHV-1 antibodies in bovine sera. Comparative results of IBT and the virus neutralisation reaction did not show statistically reliable differences.

Animals↗
PubMed1968

Defectiveness of interferon production and of rubella virus interference in a line of African green monkey kidney cells (Vero).

Vero cells, a line of African green monkey kidney cells, failed to produce interferon when infected with Newcastle disease, Sendai, Sindbis, and rubella viruses, although the cells were sensitive to interferon. Further, infection of Vero cells with rubella virus did not result in interference with the replication of echovirus 11, Newcastle disease virus, or vesicular stomatitis virus, even in cultures where virtually every cell was infected with rubella virus. Under the same conditions, BSC-1 cells and other cells of primate origin produced interferon and showed rubella virus interference. The results indicate that the presence of rubella virus in the cell does not in itself exclude multiplication of other viruses and that rubella virus interference appears to be linked to the capability of the cell to produce interferon.

Animals↗
PubMed1986

In ovo interference of embryo non-lethal avian infectious bronchitis viruses (IBV) with velogenic Newcastle disease virus and embryo adapted IBV.

Avian infectious bronchitis virus (IBV) interfered with the lethal effects of velogenic Newcastle disease virus (NDV) and embryo adapted IBV in eggs previously inoculated with non-lethal IBV. Greater interference was noted in eggs superinfected with embryo adapted IBV than velogenic NDV. The interference could be eliminated by treating the initial IBV with homologous anti-IBV serum.

Animals↗