viral release from host cell

Definition

Target type: biologicalprocess

The dissemination of mature viral particles from a host cell, e.g. by cell lysis or the budding of virus particles from the cell membrane. [GOC:jl]

Viral release from the host cell is a complex and multifaceted process that involves a series of events orchestrated by the virus to escape the confines of its cellular prison and spread to new targets. The specific mechanisms employed by different viruses vary considerably, but some common themes emerge:

**1. Budding:** This is a widely adopted strategy, particularly among enveloped viruses like HIV, influenza, and Ebola. The viral genome encodes proteins that integrate into the host cell membrane, forming a scaffold-like structure. As new viral particles are assembled, they bud from the plasma membrane, acquiring their envelope in the process. This envelope, derived from the host cell membrane, is studded with viral glycoproteins essential for attachment to and entry into new target cells.

**2. Lysis:** This method is more drastic, involving the destruction of the host cell to release progeny virions. This is typical of non-enveloped viruses like poliovirus and adenoviruses. These viruses replicate within the cytoplasm of the host cell, using the host's cellular machinery to produce new viral components. Once a critical mass of virions has been assembled, viral proteins trigger the breakdown of the cell membrane, causing the host cell to burst open and release the newly formed viral particles.

**3. Exocytosis:** This mechanism is employed by certain viruses, including herpes simplex virus (HSV). Viral particles are packaged into membrane-bound vesicles within the host cell. These vesicles then move towards the cell membrane and fuse with it, releasing the viral particles into the extracellular environment.

**4. Cell-to-cell spread:** Some viruses, like the human immunodeficiency virus (HIV), can bypass the need for release into the extracellular environment by directly spreading from infected cell to uninfected cell. This occurs through the formation of intercellular bridges or nanotubes, allowing viral particles to move between cells without being exposed to the immune system.

**The release process is tightly regulated by the virus, and the efficiency of release can be influenced by a number of factors, including:

* **Host cell factors:** The type and state of the host cell can impact viral release. For example, some viruses preferentially release from specific cell types or during specific stages of the cell cycle.
* **Viral factors:** The specific proteins encoded by the viral genome, such as the envelope glycoproteins and the proteins involved in lysis, are crucial for efficient release.
* **Immune response:** The host's immune system can hinder viral release through the production of antibodies that neutralize viral particles or by targeting infected cells for destruction.

**Consequences of Viral Release:**

Viral release is the culmination of the viral replication cycle and is essential for the propagation and spread of infection. Successful release allows the virus to escape the host cell and infect new cells, amplifying the infection and potentially causing disease. The consequences of viral release can vary depending on the virus and the host, ranging from mild symptoms to severe disease and death.

**Understanding the mechanisms of viral release is critical for developing antiviral therapies that can block this crucial step in the viral life cycle. By targeting specific viral proteins or cellular pathways involved in release, it may be possible to prevent the spread of infection and limit the severity of disease.**'
"

Proteins (5)

Compounds (39)