Viral latency

Definition

Viral latency is a state in which a virus remains inactive within a host's cells after initial infection, allowing it to evade the immune response and potentially reactivate later. This characteristic enables viruses to persist in the host for long periods, influencing disease progression and transmission dynamics.

5 Must Know Facts For Your Next Test

1. Many viruses, such as herpes simplex virus (HSV) and varicella-zoster virus (VZV), are well-known for their ability to establish latency in specific tissues.
2. Latent viruses can remain dormant for years, sometimes reactivating due to triggers like stress, immunosuppression, or other infections.
3. During latency, viral proteins may be expressed at low levels, which can interfere with the host's immune response without triggering a full-blown infection.
4. The mechanism of latency involves specific interactions between viral and host cell factors that help the virus integrate or maintain its genome in a non-replicative form.
5. Understanding viral latency is crucial for developing effective treatments and vaccines, as it poses challenges for eradicating infections from the body.

Review Questions

• How does viral latency affect the immune response of the host?
  • Viral latency allows viruses to evade the host's immune response by remaining dormant and not producing detectable viral particles. This means that the immune system does not actively target these latent viruses, enabling them to persist within cells. When reactivation occurs, however, the immune system may respond more vigorously if it recognizes previously encountered viral antigens.
• Discuss how the lytic and lysogenic cycles relate to the concept of viral latency.
  • The lytic cycle results in the active replication and release of new viral particles, leading to cell death and symptoms of infection. In contrast, the lysogenic cycle involves the integration of viral DNA into the host genome, which is central to establishing viral latency. During this phase, the virus remains inactive until specific stimuli trigger reactivation, transitioning from a latent state back to the lytic cycle.
• Evaluate the implications of viral latency on chronic viral infections and their management.
  • Viral latency has significant implications for chronic infections because it complicates treatment strategies. Since latent viruses can remain undetectable and unresponsive to antiviral therapies, they pose challenges for complete eradication. Managing chronic infections thus requires a deeper understanding of reactivation triggers and potential strategies that target both active and latent forms of the virus, including therapeutic approaches aimed at strengthening the host's immune response or directly targeting latent reservoirs.

Related terms

Provirus: A provirus is the viral genome integrated into the host cell's DNA during latency, allowing the virus to replicate along with the host's genetic material.

Reactivation: Reactivation is the process by which a latent virus becomes active again, often leading to renewed viral replication and potential disease symptoms.

Immunoevasion: Immunoevasion refers to the strategies employed by viruses to avoid detection and destruction by the host's immune system.