Interferon Response: Videos & Practice Problems

Interferons (IFNs) are crucial cytokines that provide antiviral defense by warning neighboring cells of viral infections. When pattern recognition receptors (PRRs) detect viral RNA in an infected cell, it secretes interferons, which diffuse to uninfected cells, prompting them to produce inactive antiviral proteins (IAVPs). If these neighboring cells encounter the virus, IAVPs activate into active antiviral proteins (AVPs), leading to apoptosis, which prevents viral replication. This interferon response is vital for limiting virus spread and buying time for the immune system to eliminate the infection.

Interferon Response

The interferon response is a crucial aspect of the innate immune system, specifically functioning as a second line of defense against viral infections. Interferons, commonly abbreviated as IFNs, are a type of cytokine, which are chemical signals that facilitate communication between cells. These cytokines play a vital role in providing antiviral effects, helping to protect neighboring cells from viral attacks.

When a cell is infected by a virus, it can release interferons, which then signal nearby cells to enhance their antiviral defenses. This process not only helps to limit the spread of the virus but also activates various immune responses that contribute to the overall defense mechanism of the body.

Understanding the steps involved in the interferon response is essential for grasping how the body combats viral infections. This response is part of the broader framework of innate immunity, which serves as the body's immediate defense against pathogens. In subsequent discussions, we will delve deeper into the mechanisms of the interferon response and its significance in antiviral defense.

Steps of the Interferon Response

The interferon response is a crucial mechanism in the body's defense against viral infections, primarily functioning to protect neighboring cells from becoming infected. When a cell is infected by a virus, it utilizes pattern recognition receptors (PRRs) to detect viral RNA. In response, the infected cell can produce and secrete interferons (IFNs), signaling molecules that play a vital role in the antiviral response.

Once released, interferons diffuse to nearby uninfected cells, binding to their receptors. This interaction prompts the neighboring cells to produce inactive antiviral proteins (IAVPs). Although these proteins are inactive initially, they are prepared to respond quickly if the neighboring cell encounters the virus. The presence of IAVPs serves as a preemptive defense mechanism, allowing the cell to react swiftly to a potential infection.

If the neighboring cell is later infected by the virus, the detection of viral RNA activates the IAVPs, converting them into active antiviral proteins (AVPs). These AVPs play a critical role in halting viral replication by degrading the cell's mRNA, effectively stopping protein synthesis necessary for viral replication. This process leads to apoptosis, or programmed cell death, which, while resulting in the death of the infected cell, prevents the virus from using it as a host for replication.

In summary, the interferon response is a vital part of the immune system's strategy to limit viral spread. By warning neighboring cells and enabling them to prepare antiviral defenses, the body can effectively slow down or prevent the replication of viruses. This response not only protects individual cells but also contributes to the overall health of the organism by buying time for the immune system to eliminate the virus completely.

How does the interferon response provide anti-viral protection?

• A. Interferons bind to the virus neutralizing it.
• B. Interferons stimulate neighboring cells to produce anti-viral proteins.
• C. Interferons prevent the virus from entering the cell.
• D. Interferons prevent the virus from leaving the infected cell and infecting neighboring cells.

Answer: (B)

If a cell produces antiviral proteins (AVPs) what occurs when that cell encounters dsRNA?

• A. The antiviral proteins trigger the production of iAVPs.
• B. The antiviral proteins cease protein translation in the cell so no viral proteins can be made.
• C. The antiviral proteins become activated and the cell undergoes apoptosis to stop the viral spread.
• D. The antiviral proteins trigger the production of interferon proteins to warn neighboring cells of viral infection.

Answer: (C)

How does the interferon response to an invading virus result in the infected cell undergoing apoptosis?

• A. Detection of viral RNA triggers the degradation of host RNA and stops translation which results in cell death.
• B. Detection of viral proteins inactivates the AVPs which triggers cells death.
• C. Detect of viral RNA ceases all functions of the cell and results in cell lysis and release of newly made viruses.
• D. Detection of viral proteins causes pores to form in the surface of the cell resulting in apoptosis.

Answer: (A)

Which of the following cells can induce viral-infected cells to undergo apoptosis?

• A. Neutrophils.
• B. NK cells.
• C. Eosinophils.
• D. B cells.
• E. Basophils.
• F. Red blood cells.

Answer: (B)

Which of the following statements about interferon is incorrect?
a) It only works on a few specific types of virus.
b) It makes cells resistant to viral infection.
c) It is a species-specific molecule.
d) It does not directly inactivate viruses.

• A. It only works on a few specific types of virus.
• B. It makes cells resistant to viral infection.
• C. It is a species-specific molecule.
• D. It does not directly inactivate viruses.

Answer: (A)

Here’s what students ask on this topic:

What are interferons and how do they function in antiviral defense?

Interferons (IFNs) are a type of cytokine, which are chemical signals used for communication between cells. They play a crucial role in antiviral defense by warning neighboring cells of viral infections. When pattern recognition receptors (PRRs) in an infected cell detect viral RNA, the cell secretes interferons. These interferons then diffuse to uninfected neighboring cells, prompting them to produce inactive antiviral proteins (IAVPs). If these neighboring cells later encounter the virus, the IAVPs activate into active antiviral proteins (AVPs), leading to apoptosis. This programmed cell death prevents the virus from using the cell to replicate, thereby limiting the spread of the virus and buying time for the immune system to eliminate the infection.

How do pattern recognition receptors (PRRs) contribute to the interferon response?

Pattern recognition receptors (PRRs) are crucial for initiating the interferon response. These receptors are located in cells and are responsible for detecting viral components, such as viral RNA. When PRRs in an infected cell recognize viral RNA, they trigger the production and secretion of interferons (IFNs). These interferons then diffuse to neighboring uninfected cells, warning them of the viral presence. This warning prompts the neighboring cells to produce inactive antiviral proteins (IAVPs), which can later be activated to combat the virus if the neighboring cells become infected. Thus, PRRs play a vital role in detecting viral infections and initiating the interferon response to limit viral spread.

What are inactive antiviral proteins (IAVPs) and how do they function?

Inactive antiviral proteins (IAVPs) are proteins produced by neighboring cells in response to interferons (IFNs) released from an infected cell. These proteins are initially inactive and do not perform any antiviral functions until they are needed. If a neighboring cell that has produced IAVPs becomes infected by a virus, the detection of viral RNA activates these IAVPs into active antiviral proteins (AVPs). The AVPs then inhibit viral replication by stopping the translation of the cell's mRNA and triggering apoptosis, or programmed cell death. This process prevents the virus from using the cell to replicate, thereby limiting the spread of the virus.

What role does apoptosis play in the interferon response?

Apoptosis, or programmed cell death, plays a critical role in the interferon response by preventing viral replication. When a neighboring cell that has produced inactive antiviral proteins (IAVPs) becomes infected by a virus, the detection of viral RNA activates these IAVPs into active antiviral proteins (AVPs). The AVPs then degrade the cell's mRNA, halting protein synthesis and triggering apoptosis. Although apoptosis results in the death of the infected cell, it also prevents the virus from using the cell as a host to replicate. This self-sacrifice mechanism helps to limit the spread of the virus and buys time for the immune system to eliminate the infection.

How do interferons help in limiting the spread of a virus?

Interferons (IFNs) help limit the spread of a virus by warning neighboring cells of an infection. When an infected cell detects viral RNA through its pattern recognition receptors (PRRs), it secretes interferons. These interferons diffuse to neighboring uninfected cells, prompting them to produce inactive antiviral proteins (IAVPs). If these neighboring cells later encounter the virus, the IAVPs activate into active antiviral proteins (AVPs), which halt viral replication by stopping protein synthesis and triggering apoptosis. This process prevents the virus from using the neighboring cells to replicate, thereby limiting its spread and buying time for the immune system to eliminate the infection.