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Inhibition of human parainfluenza virus-3 replication by interferon and human MxA
1Department of Molecular Biology Research Institute, Cleveland Clinic Foundation, Ohio 44195, USA.
Abstract:
We have investigated the IFN-mediated inhibition of human parainfluenza virus-3 (HPIV-3) replication in cultured human A549 cells. IFN-alpha inhibited the virus yield significantly with concomitant reduction of viral RNA accumulation by more than 90%. Further studies indicated that the inhibitory action of IFN was at the level of primary transcription of HPIV3 replication. Since the IFN-inducible protein, MxA, has been shown to inhibit virus replication in several RNA viruses, we examined the role of MxA in HPIV-3 replication using a stably transfected human glioblastoma cell line expressing MxA. In these cells HPIV-3 replication was decreased by more than 100-fold depending on the virus dosage used with concomitant inhibition of viral RNA synthesis by about 80%. However, the viral primary transcription was not affected in this MxA-producing cell line. In contrast, in the parental cell line IFN-mediated inhibition occurred at the primary transcription step of HPIV-3 replication. These data suggest that in addition to MxA, other IFN-inducible proteins are involved in the anti-HPIV-3 effect of IFN in both the cell lines used.
Insights
Interferon-alpha (IFN) significantly inhibits human parainfluenza virus-3 (HPIV-3) replication by affecting primary viral transcription. The MxA protein contributes to this inhibition, but other IFN-inducible proteins also play a role in controlling HPIV-3.
Area of Science:
- Virology
- Immunology
- Cell Biology
Background:
- Human parainfluenza virus-3 (HPIV-3) is a significant respiratory pathogen.
- Interferons (IFNs) are crucial cytokines for antiviral defense.
- The role of specific IFN-inducible proteins in HPIV-3 inhibition requires further elucidation.
Purpose of the Study:
- To investigate the mechanism of IFN-mediated inhibition of HPIV-3 replication.
- To determine the specific role of the IFN-inducible protein MxA in controlling HPIV-3.
- To identify other potential IFN-induced antiviral factors against HPIV-3.
Main Methods:
- HPIV-3 replication assays in A549 cells treated with IFN-alpha.
- Quantification of viral RNA accumulation and primary transcription.
- Analysis of HPIV-3 replication in MxA-expressing glioblastoma cells and parental cell lines.
Main Results:
- IFN-alpha significantly reduced HPIV-3 yield and viral RNA by over 90%, primarily by inhibiting primary transcription.
- MxA expression in a transfected cell line decreased HPIV-3 replication over 100-fold and viral RNA synthesis by 80%, without affecting primary transcription.
- In contrast, IFN-mediated inhibition in parental cells occurred at the primary transcription step.
Conclusions:
- IFN-alpha effectively inhibits HPIV-3 replication through multiple mechanisms.
- MxA protein is a key factor in IFN-induced antiviral activity against HPIV-3.
- Other IFN-inducible proteins contribute to the overall antiviral response against HPIV-3.