What is the Difference Between Cytokines and Interferons

The main difference between cytokines and interferons is that cytokines are substances produced by the cells of the immune system affecting other cells, whereas interferons are a group of cytokines that interfere with viral infection. 

Cytokines and interferons are two substances produced by the cells of the immune system to affect other cells. Chemokines, interleukins, tumor necrosis factors, and lymphokines are the other types of cytokines.

Key Areas Covered

1. What are Cytokines
– Definition, Features, Function
2. What are Interferons
– Definition, Features, Function
3. Similarities Between Cytokines and Interferons
– Outline of Common Features
4. Difference Between Cytokines and Interferons
– Comparison of Key Differences

Key Terms 

Cytokines, Interferons

What are Cytokines

Cytokines are small proteins secreted by the immune system’s activated cells to affect other cells. They can be either polypeptides or glycoproteins. Also, the main function of cytokines is to regulate the immune response’s nature, intensity, and duration by binding to the receptors on the target cells. Additionally, cytokines regulate hematopoiesis as well. Importantly, interferons, chemokines, interleukins, tumor necrosis factors, and lymphokines are the types of cytokines. Characteristics of cytokines are as below.

• Pleiotropic molecules, a particular type of cytokine, can exert different effects on different types of cells in the immune system,
• Also, redundant since different cytokines can exert the same effect on a particular type of immune cell,
• Bind to the receptors with a high affinity. Thereby, only a small concentration (picomolar) is sufficient for exerting the effect,
• Synergize with each other,
• Antagonize each other,
• One cytokine can induce the production of a second cytokine by its cascade effect,
• Induce the formation of cytokine receptors.
  
  

  Figure 1: Effects of Cytokines

Furthermore, the type of action of a cytokine can be either autocrine, paracrine, or endocrine:

• Autocrine cytokines bind to the receptors of the cell for secretion
• Also, paracrine cytokines bind to the receptors of the cells with proximity to the cells of secretion
• Endocrine cytokines bind to the receptors of the cells in a distinct part of the body by traveling through the blood

Further, four Structural families of cytokines can be identified. They are hematopoietin (IL-2, IL-4), interferon (IFN-α, β, γ), chemokine, and tumor necrosis families.

What are Interferons

Interferons are a group of signaling molecules produced by the host cells in the presence of viruses. Importantly, they increase the antiviral defense in the nearby cells. Also, they are cytokines used to communicate with nearby cells. Thereby, they protect nearby cells from viral infections. they activate the body’s immune system especially; they activate macrophages and natural killer cells. Additionally, they increase the host defense by up-regulating the antigen presentation and increasing MHC antigens’ expression. Importantly, interferons and other cytokines produce fever, flu-like symptoms, and muscle pain.

Figure 2: Interferons

Moreover, three interferons occur in the body depending on the receptor they interact with, and they are interferon I, II, and III. Interferon type I interacts with the IFN-α/β receptors. Also, it is produced when the body recognizes an invading virus. Further, fibroblasts and monocytes produce type I interferon. In comparison, cytotoxic T cells and type I T helper cells produce type II interferons. However, type III interferons are more recently produced and occur in viral and fungal infections.

Similarities Between Cytokines and Interferons

• Cytokines and interferons are two substances that affect cells.
• Also, cells of the immune system produce them.
• Additionally, they allow cell-to-cell communication. 

Difference Between Cytokines and Interferons

Definition

Cytokines refer to any of several substances, such as interferon, interleukin, and growth factors, which are secreted by certain immune system cells and affect other cells. In contrast, interferons refer to a protein released by animal cells, usually in response to a virus’s entry, which inhibits virus replication.

Significance

Also, cytokines are substances produced by the immune cells, while interferons are a group of cytokines. 

Function

However, cytokines are produced by the immune system cells to communicate with other cells, while interferons can affect viral infections. 

Conclusion

In brief, cytokines and interferons are two substances produced by the body’s immune cells. Immune system cells produce cytokines to affect other cells of the body. Also, interferons, interleukins, and tumor necrosis factors are types of cytokines. In comparison, interferons are produced in viral infections. Therefore, the main difference between cytokines and interferons is their significance.  

References:

1. Zhang JM, An J. Cytokines, inflammation, and pain. Int Anesthesiol Clin. 2007 Spring;45(2):27-37. doi: 10.1097/AIA.0b013e318034194e. PMID: 17426506; PMCID: PMC2785020.
2. Interferon. Interferon – an overview | ScienceDirect Topics. (n.d.). https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/interferon

Image Courtesy:

1. “Signal transduction pathways” By cybertory – Own work (CC-BY SA 3.0) via Commons Wikimedia
2. “1RH2 Recombinant Human Interferon-Alpha 2b-01” By Nevit Dilmen – Own Work (CC-BY SA 3.0) via Commons Wikimedia