Interferons

Definition

Interferons are a group of signaling proteins produced by host cells in response to viral infections and other immune stimuli. They play a critical role in the immune response by enhancing the ability of immune cells to fight off pathogens, particularly viruses, and by regulating the activity of both innate and adaptive immune systems.

5 Must Know Facts For Your Next Test

1. Interferons are classified into three main types: Type I (including IFN-α and IFN-β), Type II (IFN-γ), and Type III (IFN-λ), each playing different roles in the immune response.
2. Type I interferons are produced by almost all cells in response to viral infections, while Type II is primarily produced by activated T cells and natural killer cells.
3. Interferons can induce the expression of genes that help inhibit viral replication, enhancing the antiviral state in neighboring cells.
4. They also enhance the activity of natural killer cells and macrophages, which are essential for eliminating infected cells.
5. Interferons have therapeutic uses, particularly in the treatment of certain viral infections and cancers, demonstrating their importance beyond just innate immunity.

Review Questions

• How do interferons enhance the immune response against viral infections?
  • Interferons enhance the immune response against viral infections primarily by activating nearby cells to enter an antiviral state. This involves inducing the expression of genes that inhibit viral replication, making it harder for viruses to spread. Additionally, interferons stimulate the activity of immune cells like natural killer cells and macrophages, increasing their ability to target and eliminate infected cells.
• Compare the roles of Type I and Type II interferons in immune responses.
  • Type I interferons, such as IFN-α and IFN-β, are produced by nearly all cells in response to viral infections and serve to trigger an antiviral state in neighboring cells. In contrast, Type II interferon (IFN-γ) is primarily produced by activated T cells and natural killer cells and plays a critical role in promoting adaptive immunity by enhancing antigen presentation and activating macrophages. Together, they coordinate both innate and adaptive responses, providing a comprehensive defense against pathogens.
• Evaluate the significance of interferons in both therapeutic contexts and natural immune responses.
  • Interferons hold significant therapeutic potential as they are used in treating various viral infections like hepatitis C and certain types of cancer. Their ability to boost the immune system's antiviral capabilities makes them valuable in clinical settings. In natural immune responses, interferons play a critical role in alerting neighboring cells to infections, regulating immune functions, and ensuring a timely response to threats. This dual role illustrates their importance not only as mediators of immunity but also as tools for modern medicine.

Related terms

Cytokines: Small proteins that are crucial in controlling the growth and activity of other immune system cells and blood cells, acting as signaling molecules in the immune response.

Antiviral Response: The series of immune system processes initiated by interferons and other factors to protect the host from viral infections.

Natural Killer Cells: A type of lymphocyte that plays a major role in the host-rejection of tumors and virally infected cells, often activated by interferons.