defense response to virus

Definition

Target type: biologicalprocess

Reactions triggered in response to the presence of a virus that act to protect the cell or organism. [GOC:ai]

The defense response to virus is a complex and multifaceted process that involves the coordinated action of the innate and adaptive immune systems.

**Innate Immune Response:**
* **Pattern Recognition Receptors (PRRs):** Immune cells possess PRRs that recognize pathogen-associated molecular patterns (PAMPs) specific to viruses, such as double-stranded RNA, single-stranded RNA, and viral proteins.
* **Interferon (IFN) Production:** Upon PRR activation, cells produce type I interferons (IFN-α and IFN-β). These cytokines trigger antiviral responses in neighboring cells by inducing the expression of antiviral genes.
* **Antiviral Gene Induction:** IFNs activate signaling pathways that lead to the production of antiviral proteins, such as protein kinase R (PKR) and 2'-5' oligoadenylate synthetase (OAS).
* **Viral Replication Inhibition:** PKR inhibits protein synthesis, while OAS triggers RNA degradation, both contributing to viral replication inhibition.
* **Immune Cell Recruitment:** IFNs attract immune cells, such as natural killer (NK) cells, macrophages, and dendritic cells, to the site of infection.
* **NK Cell Activity:** NK cells kill virus-infected cells directly through the release of cytotoxic granules.

**Adaptive Immune Response:**
* **Antigen Presentation:** Dendritic cells capture viral antigens and migrate to lymph nodes, where they present them to T cells.
* **T Cell Activation:** Specific T cells recognizing the viral antigen are activated, leading to the production of cytotoxic T lymphocytes (CTLs) and helper T cells.
* **CTL Activity:** CTLs directly kill virus-infected cells through the release of cytotoxic granules.
* **Antibody Production:** Helper T cells stimulate B cells to produce antibodies specific to viral antigens.
* **Antibody Function:** Antibodies neutralize viruses by binding to them, preventing their entry into cells.

**Additional Mechanisms:**
* **Autophagy:** This process eliminates virus-infected cells and viral particles within cells.
* **Apoptosis:** This programmed cell death mechanism eliminates infected cells to prevent further viral spread.

Overall, the defense response to virus involves a cascade of events triggered by the innate immune system, followed by the activation of the adaptive immune system. This coordinated response aims to control viral replication, eliminate infected cells, and prevent further spread of the virus.'
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Proteins (37)

Compounds (2,634)