Interferon

Interferons- Definition, Features, Types, Production, Cytokine

Introduction:

  • Interferon is a type of protein produced and released by cells in response to the presence of pathogens, such as viruses, or other foreign substances that may harm the body.
  • It is part of the body’s natural defense system and helps to protect against infections and other diseases.
  • Interferon works by inhibiting the replication and spread of viruses, activating immune cells, and promoting inflammation, which helps the body to fight off infections and other harmful substances.
Interferons

Fig: Interferons

Features:

Inhibitory effect on viral replication: Interferons inhibit the replication and spread of viruses, which helps to prevent the infection from spreading throughout the body.

Activation of immune cells: Interferons activate immune cells, such as white blood cells and natural killer cells, which help to fight off infections and other harmful substances.

Promotion of inflammation: Interferons promote inflammation, which helps to protect the body against infections and other harmful substances.

Production by various cells: Interferons are produced by a variety of cells, including white blood cells, fibroblasts, and endothelial cells.

History:

The discovery of interferons dates back to the 1950s, when scientists first observed that cells infected with viruses could inhibit the replication of other viruses. This led to the identification of interferons as proteins that are produced and released by cells in response to viral infections or other forms of cellular stress.

The first interferon to be identified was alpha interferon, which was isolated and characterized in the late 1950s. Beta interferon was identified a few years later, and gamma interferon was discovered in the 1970s.

In the 1980s, researchers began to investigate the potential use of interferons as therapeutic agents. Alpha interferon was approved by the US Food and Drug Administration (FDA) for the treatment of hairy cell leukemia in 1986, and it has since been approved for the treatment of a variety of viral infections and certain types of cancer. Beta interferon was approved by the FDA for the treatment of multiple sclerosis in 1993, and gamma interferon has been approved for the treatment of chronic granulomatous disease, a rare genetic disorder.

Types:

Alpha interferons are produced and released by virus-infected cells and certain tumor cells. They have antiviral and antitumor properties and are used to treat a variety of viral infections and certain types of cancer.

Beta interferons are produced and released by immune cells called macrophages and monocytes. They have antiviral and immune-regulatory properties and are used to treat multiple sclerosis and some other autoimmune disorders.

Gamma interferons are produced and released by T cells and natural killer cells. They have immune-regulatory and antiviral properties and are involved in activating and regulating the immune system. Gamma interferons are used to treat chronicgranulomatous disease, a rare genetic disorder, and to boost the immune system in people with cancer or HIV/AIDS.

Mode of action:

  • Interferons are proteins produced and released by cells in response to viral infections or other forms of cellular stress. They have a variety of functions that includes activating the immune system and inhibiting the replication of viruses.
  • The mode of action of interferons depends on the specific type of interferon and the target cells. In general, interferons bind to specific receptors on the surface of target cells, activating signaling pathways that lead to a variety of cellular responses.
  • One of the main mechanisms by which interferons inhibit viral replication is by inducing the production of proteins called antiviral effectors, which interfere with various stages of the viral life cycle. For example, interferons can induce the production of enzymes that inhibit the synthesis of viral RNA or proteins, or they can stimulate the production of proteins that inhibit the release of viral particles from infected cells.
Interferon affecting neighboring cells
Source: http://www.microbiologybook.org/book/virol-sta.htm

Fig: Interferon affecting neighboring cells

  • In addition to their antiviral effects, interferons also have immune-regulatory properties. They can stimulate the production of immune cells, such as T cells and natural killer cells, and they can enhance the activity of these cells. Interferons can also inhibit the proliferation of certain types of immune cells, such as T cells and B cells, and they can modulate the production of cytokines, which are signaling proteins that play a key role in the immune response.

Pathway:

Production and release: Interferons are produced and released by cells in response to viral infections or other forms of cellular stress. There are three main types of interferons: alpha, beta, and gamma. Each type of interferon is produced and released by different types of cells in response to different stimuli.

Receptor binding: Interferons bind to specific receptors on the surface of target cells. The binding of interferons to their receptors activates intracellular signaling pathways that lead to a variety of cellular responses.

General action of interferon
Source: Google

Fig: General action of interferon

Signal transduction: The binding of interferons to their receptors activates intracellular signaling pathways that involve the phosphorylation of intracellular proteins. These signaling pathways lead to the activation of transcription factors that bind to specific DNA sequences and stimulate the transcription of specific genes.

Gene expression: The activation of transcription factors leads to the transcription of specific genes, resulting in the production of proteins called antiviral effectors. These proteins inhibit the replication of viruses by interfering with various stages of the viral life cycle.

Cellular response: The activation of the immune system and the inhibition of viral replication are the main cellular responses to interferons. These responses involve the activation of immune cells, such as T cells and natural killer cells, and the modulation of the production of cytokines, which are signaling proteins that play a prominent role in the immune response.

Commercial Production of interferons:

There are several methods for producing interferons commercially.

Recombinant DNA technology involves the use of genetically modified cells, such as bacteria or yeast, to produce large quantities of interferons. This method involves the insertion of a gene encoding the desired interferon into the genome of the host cells, which are then grown in large fermentation tanks under controlled conditions. The interferon is purified from the culture supernatant or cell lysate by a series of steps, including centrifugation, filtration, and chromatographic separation.

Tissue culture-based methods involve the use of cells that naturally produce interferons, such as fibroblasts or lymphocytes, to produce large quantities of interferons. These cells are cultured in bioreactors or cell culture flasks and are stimulated to produce interferons using various methods, such as chemical agents or viral infections. The interferon is purified from the culture supernatant or cell lysate using similar methods as described above.

Cytokines Vs Interferons:

Cytokines and interferons are both types of signaling proteins involved in the immune response. They are produced and released by immune cells in response to various stimuli, such as viral infections or other forms of cellular stress.  However, there are some key differences between cytokines and interferons.

Structure: Cytokines are a diverse group of proteins that vary in size and structure. They typically have a molecular weight of less than 20 kDa and can be classified into several families based on their structures and functions. Interferons are a group of proteins that are classified into three main types: alpha, beta, and gamma. Each type of interferon has a distinct structure and is produced and released by different types of cells in response to different stimuli.

Production and release: Cytokines are produced and released by a variety of immune cells, such as T cells, B cells, and macrophages, as well as by non-immune cells, such as fibroblasts and endothelial cells. They are induced by various stimuli, such as viral infections, tissue damage, or exposure to antigens. Interferons are produced and released by cells in response to viral infections or other forms of cellular stress. Alpha, beta, and gamma are the three different types of interferons. Each type of interferon is produced and released by different types of cells in response to different stimuli.

Mechanism of action: Cytokines act on a variety of target cells, including immune cells, to stimulate or inhibit various immune responses. They bind to specific receptors on the surface of target cells and activate signaling pathways that lead to a variety of cellular responses. Interferons bind to specific receptors on the surface of target cells and activate signaling pathways that lead to a variety of cellular responses, including the activation of the immune system and the inhibition of viral replication.

Functions: Cytokines have a variety of functions, including activating the immune system, regulating immune responses, and promoting inflammation. They are involved in a wide range of immune responses, including the activation of T cells and B cells, the production of antibodies, and the recruitment of immune cells to sites of infection or tissue damage. Interferons have a variety of functions, including activating the immune system and inhibiting the replication of viruses. They are used to treat a variety of viral infections and certain types of cancer, as well as some autoimmune disorders.

Applications:

Viral infections: Interferons are used to treat a variety of viral infections, including hepatitis B and C, multiple sclerosis, human papillomavirus infections, and Kaposi’s sarcoma. They are also used to prevent the recurrence of herpes simplex virus infections.

Cancer: Interferons are used to treat certain types of cancer, including hairy cell leukemia, chronic myelogenous leukemia, and melanoma. They are also used in combination with other cancer therapies, such as chemotherapy, to enhance their effectiveness.

Autoimmune disorders: Interferons are used to treat some autoimmune disorders, such as multiple sclerosis and Crohn’s disease. They are also used to treat some genetic disorders, such as chronic granulomatous disease, which is a rare genetic disorder characterized by an impaired immune system.

HIV/AIDS: Interferons are used in combination with other antiretroviral drugs to treat HIV/AIDS. They are believed to enhance the effectiveness of these drugs by inhibiting the replication of HIV and boosting the immune system.

References:

  • Sen GC. Viruses and interferons. Annu Rev Microbiol 2001; 55:255–281.
  • Houglum JE. Interferon: mechanisms of action and clinical value. Clin Pharm. 1983 Jan-Feb;2(1):20-8. PMID: 6192965.
  • Ho, M., 1962. Interferons. New England Journal of Medicine, 266(24), pp.1258-1264.
  • Lauta VM. Update dell’impiego degli interferons nella pratica clinica [Update on the use of interferons in clinical practice]. Clin Ter. 1995 Jun-Jul;146(6-7):393-448. Italian. PMID: 7586995.

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