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Selective mechanisms utilized by persistent and oncogenic viruses to interfere with antigen processing and
1Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Israel.
Abstract:
Cell-mediated immunity is effective against cells harboring active virus replication, and is critical for the elimination of ongoing infections, regression of virus-associated tumors, and reducing or preventing the reactivation of persistent viruses. The capacity of persistent and oncogenic viruses to maintain a long-term relationship with their host presupposes viral mechanisms for circumventing antiviral defenses. By suppressing the expression of molecules associated with antigen processing and presentation, viruses abrogate the major immune mechanism that deals with the elimination of infected and tumor cells. This is accomplished either by transcriptional downregulation of genes encoding class I MHC antigens, peptide transporter molecules, and the proteasome-associated LMP subunits, or by interfering with transport of class I molecules to the cell surface. In some cases viruses shut off the expression of most viral proteins during latency or express mainly nonimmunogenic or antagonistic peptide epitopes. This review describes selective mechanisms utilized by viruses for interference with antigen processing and presentation, and addresses their significance for in vivo viral persistence and tumor progression.
Insights
Viruses evade cell-mediated immunity by disrupting antigen processing and presentation. This viral immune evasion is crucial for persistent infections and tumor development.
Area of Science:
- Immunology
- Virology
- Molecular Biology
Background:
- Cell-mediated immunity eliminates infected cells and tumors.
- Persistent viruses and oncogenic viruses evade immune responses.
- Viruses suppress antigen presentation to escape immune detection.
Purpose of the Study:
- To review viral mechanisms for interfering with antigen processing and presentation.
- To discuss the significance of these mechanisms for viral persistence and tumor progression.
Main Methods:
- Review of scientific literature on viral immune evasion strategies.
- Analysis of molecular mechanisms used by viruses to interfere with antigen processing and presentation.
Main Results:
- Viruses downregulate genes for MHC class I, peptide transporters, and proteasome subunits.
- Viruses interfere with the transport of MHC class I molecules to the cell surface.
- Some viruses reduce viral protein expression or present non-immunogenic epitopes during latency.
Conclusions:
- Viral interference with antigen processing and presentation is a key strategy for immune evasion.
- These mechanisms contribute to viral persistence in the host.
- Interference with antigen presentation facilitates virus-associated tumor progression.