How Interferon Works: Key Roles and Biological Significance
Several proteins which are released by the body as a defensive form are termed interferons. Along with that, they act as important modulators of the human body immune system. They are named for their ability to interfere with viral proliferation.
There are various types of interferons which are produced by the body at a rapid rate to fight against infectious disease caused by various pathogens like bacteria, virus, etc. They also have the ability to fight against various fungal and bacterial infections as they inhibit their cell division and promote the differentiation of cells. Every vertebrate has the ability to produce interferons.
They are categorized as cytokines, small proteins involved in intercellular signalling. They are secreted by cells in response to stimulation by a virus or other foreign substance but they do not affect the virus’s multiplication. Additionally, they stimulate the infected cells along with those nearby to produce proteins that stop the replication of the virus within them.
Some immunoregulatory functions shown by interferons are: they stop B-lymphocyte (B-cell) activation, enhance or increase T-lymphocyte (T-cell) activity along with that also increase the cellular-destruction capability of natural killer cells.
Forms of Interferons
Mainly there are forms of interferons. They are alpha (α), beta (β), and gamma (γ). Further, they are also classified into two types i.e. type I which includes alpha and beta forms and type II which include gamma form. This division is done on the basis of types of cell that are produced by the interferons along with the functional characteristics of the protein.
The first type of interferon i.e. type I is produced by almost all types of the cell upon stimulation by a virus and their main function is to induce viral resistance in the cells whereas type II is secreted only by natural killer cells and T lymphocytes and they mainly perform activities like sending a signal to the immune system to give a response to infectious agents or cancerous growth.
Discovery of Interferons
The Discovery of Interferon was done in 1957 by British bacteriologist Alick Isaacs and Swiss microbiologist Jean Lindenmann. This research was conducted in the year 1970s and from this, it was proved that these substances could not only prevent viral infection but also suppress the growth of cancers in some laboratory animals.
Sometimes interferons are proved to be a blessing for various deadly diseases but along with that they also show some side effects like fever and fatigue as well as a decrease in the production of blood cells by the bone marrow.
Function of Interferons
Each interferon shows certain side effects as they are antiviral agents and they induce the functions of the immune system. Generally, type I of interferon is administered into the body to inhibit tumour growth in animals and termed to be beneficial in the case of human tumours. A virus-infected cell has the ability to release viral particles as they also infect nearby cells. An infected cell can also protect neighbouring cells against a potential infection of the virus by secretion of interferons.
Cells produce large amounts of enzymes known as a protein kinase in response to interferons. Another common function of interferons is to up-regulate the function of major histocompatibility complex molecules. They also suppress angiogenesis by downregulation of angiogenic stimuli deriving from tumour cells along with that they also suppress the proliferation of endothelial cells and such suppression leads to a decrease in tumour angiogenesis.
The major function of gamma interferon is to directly activate other immune cells like macrophages and natural killer cells.
FAQs on What Is Interferon?
1. What are interferons and what is their primary role in biology?
Interferons are a group of signalling proteins, classified as cytokines, that are produced and released by host cells in response to the presence of pathogens, particularly viruses. Their primary role is to 'interfere' with viral replication by triggering the defensive responses of nearby uninfected cells, effectively creating an antiviral state to limit the spread of the infection.
2. Which cells produce interferons and what triggers their release?
Most cells in the human body have the ability to produce interferons. The primary trigger for their release is the detection of viral genetic material, such as double-stranded RNA, within the cell. This signals that the cell has been invaded by a virus, prompting it to secrete interferons as a warning to neighbouring cells and to alert the broader immune system.
3. What are the main types of interferons and how do their functions differ?
There are three main types of interferons, each with distinct functions as per the CBSE/NCERT syllabus for 2025-26:
- Type I (IFN-α and IFN-β): Produced by most virus-infected cells, their main job is to inhibit viral replication in nearby cells and to activate Natural Killer (NK) cells.
- Type II (IFN-γ): Secreted mainly by immune cells like T-cells and NK cells, it is a powerful modulator of the adaptive immune response, known for activating macrophages.
- Type III (IFN-λ): This type provides localised protection by acting primarily on epithelial cells, which are common sites of initial viral entry.
4. How do interferons released by one infected cell protect its neighbouring cells?
Interferons act as a neighbourhood watch system. They do not kill viruses directly. Instead, when released from an infected cell, they bind to receptors on adjacent healthy cells. This binding initiates an internal signalling pathway that causes the healthy cell to produce a range of antiviral proteins. These proteins can degrade viral mRNA and block protein synthesis, making the cell inhospitable for any virus that tries to invade it.
5. Why are interferons considered a part of the innate immune system and not the adaptive immune system?
Interferons are a classic example of the innate immune system because their response is rapid, non-specific, and does not generate long-term memory. They act broadly against many types of viruses without prior exposure. In contrast, the adaptive immune system (involving antibodies and T-cells) is highly specific to a single pathogen and creates immunological memory, allowing for a faster and stronger response to future encounters with that same pathogen.
6. What are some examples of how interferons are used in medical treatments?
Through recombinant DNA technology, interferons are manufactured for therapeutic use. A prominent example is Interferon-alpha, which is used as a drug to treat chronic viral infections like Hepatitis C and some forms of cancer. Another example is Interferon-beta, commonly prescribed to manage the autoimmune disease multiple sclerosis by helping to reduce the frequency and severity of relapses.
