Related Experiment Videos
Different effects of IFN gamma and IFN alpha/beta on "immediate early" gene expression of HSV-1
A Klotzbücher1, S Mittnacht, H Kirchner
1German Cancer Research Center, Institute for Virus Research, Deutsches Krebsforschungszentrum, Heidelberg.
Abstract:
The effects of interferon gamma (IFN gamma) on early steps of herpes simplex virus (Type 1; HSV-1) replication in primary cultures of splenic mouse macrophages were analyzed and compared to IFN alpha/beta. Pretreatment of macrophages with recombinant murine IFN gamma led to a dose-dependent reduction in the yield of progeny virus. Inhibition of protein synthesis was observed for HSV-1 alpha, beta and gamma-proteins. Expression of the "immediate early" (IE) gene IE3 (ICP4) was investigated in detail. Steady-state level of the RNA and transcriptional activity of the gene in IFN gamma-treated cells were comparable to control-infected cells except for a delay in their kinetics. This is in contrast to IFN alpha/beta, which leads to a stable decrease in IE3 transcripts. Since IFN gamma causes a stable decrease in the IE3 gene product ICP4, our data suggest a translational inhibition of HSV-1 IE gene expression in IFN gamma-treated macrophages. Thus, IFN gamma and IFN alpha/beta inhibit HSV-1 replication by different mechanisms which may lead to a synergistic enhancement of inhibition after combined treatment.
Insights
Interferon gamma (IFN gamma) inhibits herpes simplex virus (HSV-1) replication in macrophages by affecting protein synthesis, unlike interferon alpha/beta. This suggests different mechanisms for viral inhibition by interferons.
Area of Science:
- Immunology
- Virology
- Molecular Biology
Background:
- Interferons (IFNs) are crucial cytokines in antiviral defense.
- Herpes simplex virus (HSV-1) is a common human pathogen.
- Understanding differential IFN effects on viral replication is key to developing therapies.
Purpose of the Study:
- To analyze the effects of interferon gamma (IFN gamma) on early HSV-1 replication steps.
- To compare IFN gamma's antiviral mechanisms with those of interferon alpha/beta (IFN alpha/beta).
- To investigate the impact of IFNs on viral protein synthesis and gene expression.
Main Methods:
- Primary cultures of splenic mouse macrophages were pretreated with recombinant murine IFN gamma.
- HSV-1 replication was assessed by measuring progeny virus yield and protein synthesis.
- Expression of the immediate-early gene IE3 (ICP4) was analyzed at RNA and protein levels.
Main Results:
- IFN gamma treatment resulted in a dose-dependent reduction of HSV-1 progeny virus yield.
- Both IFN gamma and IFN alpha/beta inhibited HSV-1 protein synthesis.
- IFN gamma delayed but did not stably decrease IE3 RNA levels, suggesting translational inhibition of ICP4.
Conclusions:
- IFN gamma and IFN alpha/beta inhibit HSV-1 replication through distinct mechanisms.
- IFN gamma appears to inhibit HSV-1 immediate-early gene expression at the translational level.
- Combined treatment with IFN gamma and IFN alpha/beta may offer synergistic antiviral effects.