Interferons

Author: V. Dimov, M.D., Allergist/Immunologist and Assistant Professor at University of Chicago
Reviewer: S. Randhawa, M.D., Allergist/Immunologist and Assistant Professor at NSU

Host cells produce interferons as one of the earliest responses to viral infection.

There are 3 types of interferons - remembered by the mnemonic ABG:

Alpha, IFN-α
Beta, IFN-β
Gamma, IFN-γ

IFN-α is produced by leukocytes and is encoded by 20 genes, in comparison IFN-β and IFN-γ are each encoded by a single gene. IFN-β is produced by fibroblasts and IFN-γ is produced by Th1 and NK cells.

IFN
α
αlba (white blood cells)

IFN-β
fibroβlasts


Interferon beta-1a. Image source: Wikipedia. Experimental inhaled beta interferon drug SNG001 "stops common cold-related asthma deaths" - NHS blog reviews evidence (http://goo.gl/EZL6L).


Interferon gamma. Image source: Wikipedia.

Pegylated interferon alfa-2a (commercial name Pegasys (R)) is an antiviral medication used for the treatment of chronic hepatitis C and B. Interferon beta-1a (Avonex (R)) is a medication used to treat multiple sclerosis (MS).


The 3 types of interferons, remembered by the mnemonic ABG: alpha, beta, gamma (click to enlarge the image).

Interferons bind to membrane receptors, which initiate the activation of Janus kinase (JAK)-signal transducer and activator of transcription (STAT)-signaling pathways. This leads to gene transcription.

Various interferons have been approved for clinical use:

Recombinant IFN-α-2a (Roferon-A)

Used in chronic hepatitis C, hairy cell leukemia, chronic myeloid leukemia (CML).

Recombinant IFN-α-2b (Intron-A)

Used in Kaposi’s sarcoma, chronic hepatitis B or C, malignant melanoma, follicular lymphoma, and condylomata acuminate.

IFN-α -n3 (Alferon-N)

Used for treatment of genital warts.

Pegylated IFN-α-2a (Pegasys)

Used in chronic hepatitis B or C.

IFN-β-1a (Avonex/Rebif)

Used in relapsing multiple sclerosis (MS).

IFN-β-1b (Betaseron)

Used in early or relapsing multiple sclerosis (MS).

IFN-γ 1b (Actimmune)

Used in chronic granulomatous disease (CGD).

References

Allergy and Immunology MKSAP, 3rd edition.
Advances in basic and clinical immunology in 2007. Journal of Allergy and Clinical Immunology - Volume 122, Issue 1 (July 2008).

Related Reading

Medical Immunology Syllabus. Columbia University.

Interferon regulatory factor 8 (IRF8) Mutations and Human Dendritic-Cell Immunodeficiency. NEJM, 2011.

Published: 12/15/2007
Updated: 04/19/2012