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1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart2h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

21. The Immune System

Interferon Response

21. The Immune System

Interferon Response: Videos & Practice Problems

Video Lessons Practice Worksheet

Topic summary

Interferons (IFNs) are crucial cytokines that provide antiviral defense by alerting neighboring cells of viral infections. Infected cells release IFNs, prompting nearby cells to produce inactive antiviral proteins (IAVPs). If these neighboring cells encounter the virus, IAVPs activate into active antiviral proteins (AVPs), which inhibit viral replication and trigger apoptosis, effectively sacrificing the cell to prevent further infection. This interferon response is vital for limiting viral spread and buying time for the immune system to eliminate the virus.

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Interferons

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Interferons Video Summary

Interferons, commonly abbreviated as IFNs, are a crucial type of cytokine, which are chemical signals that facilitate communication between cells. These proteins play a significant role in the immune response, particularly in providing antiviral effects. Interferons act by signaling neighboring cells to enhance their defenses against viral infections, thereby contributing to the body's innate immunity.

In the context of innate immunity, the interferon response represents the second line of defense, focusing on innate effector actions. This response is vital for the early detection and response to viral pathogens, helping to limit their spread and impact on the host. Understanding the mechanisms of the interferon response is essential for grasping how the immune system combats viral infections effectively.

In upcoming discussions, we will delve deeper into the specific steps involved in the interferon response, exploring how these cytokines orchestrate a coordinated defense against viruses. This foundational knowledge will enhance our comprehension of the broader immune response and its implications for health and disease.

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Steps of the Interferon Response

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Steps of the Interferon Response Video Summary

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, its pattern recognition receptors (PRRs) detect viral RNA, prompting the infected cell to produce and secrete interferons (IFNs). These interferons serve as signaling molecules that diffuse to nearby uninfected cells, alerting them to the viral threat.

Upon receiving the interferons, neighboring cells initiate the production of inactive antiviral proteins (IAVPs). Although these proteins are inactive initially, they are prepared to respond quickly if the neighboring cell encounters the virus. If the neighboring cell is subsequently infected, the detection of viral RNA activates the IAVPs, transforming 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 and triggering apoptosis, or programmed cell death.

While the initially infected cell may succumb to the virus and produce new viral particles, the release of interferons allows neighboring cells to preemptively defend themselves. By activating AVPs and undergoing apoptosis, these neighboring cells prevent the virus from using them as hosts for replication. This self-sacrificial act not only limits the spread of the virus but also buys time for the immune system to eliminate the infection from the body.

In summary, the interferon response is vital for limiting viral replication and protecting uninfected cells. By warning neighboring cells to prepare antiviral defenses, the body can effectively manage viral threats and enhance its overall immune response.

Problem

How does the interferon response provide anti-viral protection?

Interferons bind to the virus neutralizing it.

Interferons stimulate neighboring cells to produce anti-viral proteins.

Interferons prevent the virus from entering the cell.

Interferons prevent the virus from leaving the infected cell and infecting neighboring cells.

Problem

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

The antiviral proteins trigger the production of iAVPs.

The antiviral proteins cease protein translation in the cell so no viral proteins can be made.

The antiviral proteins become activated and the cell undergoes apoptosis to stop the viral spread.

The antiviral proteins trigger the production of interferon proteins to warn neighboring cells of viral infection.

Problem

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

Detection of viral RNA triggers the degradation of host RNA and stops translation which results in cell death.

Detection of viral proteins inactivates the AVPs which triggers cells death.

Detect of viral RNA ceases all functions of the cell and results in cell lysis and release of newly made viruses.

Detection of viral proteins causes pores to form in the surface of the cell resulting in apoptosis.

Problem

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

Neutrophils.

NK cells.

Eosinophils.

B cells.

Basophils.

Red blood cells.

Problem

Which of the following statements about interferon is incorrect?

It only works on enveloped viruses.

It decreases the spread of the virus.

It is a species-specific molecule.

It does not directly inactivate viruses.

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Here’s what students ask on this topic:

What are interferons and how do they function in the immune response?

Interferons (IFNs) are a type of cytokine, which are chemical signals used for communication between cells. They play a crucial role in the immune response by providing antiviral defense. When a cell is infected by a virus, it releases interferons. These interferons then diffuse to neighboring cells, warning them of the viral presence. In response, these neighboring cells produce inactive antiviral proteins (IAVPs). If the virus attempts to infect these cells, the IAVPs activate into active antiviral proteins (AVPs), which inhibit viral replication and trigger apoptosis, effectively sacrificing the cell to prevent further infection. This process helps limit the spread of the virus and buys time for the immune system to eliminate it.

How do interferons alert neighboring cells of a viral infection?

When a cell is infected by a virus, it can produce and secrete interferons (IFNs). These interferons diffuse to neighboring cells that have not yet been infected. Upon reaching these neighboring cells, the interferons bind to specific receptors on their surfaces. This binding acts as a warning signal, prompting the neighboring cells to produce inactive antiviral proteins (IAVPs). These IAVPs remain inactive until the neighboring cell detects viral RNA, at which point they activate into active antiviral proteins (AVPs) that inhibit viral replication and trigger apoptosis. This mechanism helps protect neighboring cells from becoming viral hosts.

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

Inactive antiviral proteins (IAVPs) are proteins produced by neighboring cells in response to interferons (IFNs) released by an infected cell. These proteins are initially inactive and do not perform any antiviral functions. However, if the neighboring cell becomes infected by the virus, the detection of viral RNA triggers the activation of IAVPs into active antiviral proteins (AVPs). The AVPs then inhibit viral replication by degrading the cell's mRNA and stopping translation, ultimately leading to apoptosis. This process sacrifices the infected cell to prevent the virus from using it 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. When a neighboring cell, warned by interferons, detects viral RNA, it activates its inactive antiviral proteins (IAVPs) into active antiviral proteins (AVPs). These AVPs inhibit viral replication by degrading the cell's mRNA and stopping translation. This process triggers apoptosis, effectively sacrificing the infected cell. By undergoing apoptosis, the cell prevents the virus from using it as a host to replicate, thereby limiting the spread of the virus. This mechanism helps control the infection and buys time for the immune system to eliminate the virus.

How does the interferon response help limit viral replication?

The interferon response helps limit viral replication by warning neighboring cells of a viral infection. When an infected cell releases interferons (IFNs), these cytokines diffuse to nearby cells and bind to their receptors. This binding prompts the neighboring cells to produce inactive antiviral proteins (IAVPs). If these cells later encounter the virus, the IAVPs activate into active antiviral proteins (AVPs), which inhibit viral replication by degrading the cell's mRNA and stopping translation. This process triggers apoptosis, sacrificing the infected cell to prevent the virus from using it to replicate. By limiting viral replication, the interferon response helps control the spread of the virus and buys time for the immune system to eliminate it.