Interferon

Interferon alpha/beta domain
The molecular structure of human interferon-alpha
Identifiers
Symbol	Interferons
Pfam	PF00143
InterPro	IPR000471
PROSITE	PDOC00225
SCOP	1au1
SUPERFAMILY	1au1
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Interferons (IFNs) are a group of signaling proteins^[1] made and released by host cells in response to the presence of several pathogens, such as viruses, bacteria, parasites, and also tumor cells. In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten their anti-viral defenses.

IFNs belong to the large class of proteins known as cytokines, molecules used for communication between cells to trigger the protective defenses of the immune system that help eradicate pathogens.^[2] Interferons are named for their ability to "interfere" with viral replication^[2] by protecting cells from virus infections. IFNs also have various other functions: they activate immune cells, such as natural killer cells and macrophages; they increase host defenses by up-regulating antigen presentation by virtue of increasing the expression of major histocompatibility complex (MHC) antigens. Certain symptoms of infections, such as fever, muscle pain and "flu-like symptoms", are also caused by the production of IFNs and other cytokines.

More than twenty distinct IFN genes and proteins have been identified in animals, including humans. They are typically divided among three classes: Type I IFN, Type II IFN, and Type III IFN. IFNs belonging to all three classes are important for fighting viral infections and for the regulation of the immune system.

Types of interferon

Based on the type of receptor through which they signal, human interferons have been classified into three major types.

• Interferon type I: All type I IFNs bind to a specific cell surface receptor complex known as the IFN-α/β receptor (IFNAR) that consists of IFNAR1 and IFNAR2 chains.^[3] The type I interferons present in humans are IFN-α, IFN-β, IFN-ε, IFN-κ and IFN-ω.^[4] In general, type I interferons are produced when the body recognizes a virus has invaded it. They are produced by fibroblasts and monocytes. However, the production of type I IFN-α is prohibited by another cytokine known as Interleukin-10. Once released, type I interferons will activate molecules which prevent the virus from producing and replicating its RNA and DNA. Overall, IFN-α can be used to treat hepatitis B and C infections, while IFN-β can be used to treat multiple sclerosis.^[2]
• Interferon type II (IFN-γ in humans): This is also known as immune interferon and is activated by Interleukin-12.^[2] Furthermore, type II interferons are released by T helper cells, type 1 specifically. However, they block the proliferation of T helper cells type two. The previous results in an inhibition of T_h2 immune response and a further induction of T_h1 immune response, which leads to the development of debilitating diseases such as multiple sclerosis.^[5] IFN type II binds to IFNGR, which consists of IFNGR1 and IFNGR2 chains and has a different receptor than type I IFN.^[2]
• Interferon type III: Signal through a receptor complex consisting of IL10R2 (also called CRF2-4) and IFNLR1 (also called CRF2-12). Although discovered more recently than type I and type II IFNs,^[6] recent information demonstrates the importance of Type III IFNs in some types of virus infections.^[7][8]

In general, type I and II interferons are responsible for regulating and activating the immune response.^[2] Expression of type I and III IFNs can be induced in virtually all cell types upon recognition of viral components, especially nucleic acids, by cytoplasmic and endosomal receptors, whereas type II interferon is induced by cytokines such as IL-12, and its expression is restricted to immune cells such as T cells and NK cells.

Function

All interferons share several common effects: they are antiviral agents and they modulate functions of the immune system. Administration of Type I IFN has been shown experimentally to inhibit tumor growth in animals, but the beneficial action in human tumors has not been widely documented. A virus-infected cell releases viral particles that can infect nearby cells. However, the infected cell can prepare neighboring cells against a potential infection by the virus by releasing interferons. In response to interferon, cells produce large amounts of an enzyme known as protein kinase R (PKR). This enzyme phosphorylates a protein known as eIF-2 in response to new viral infections; the phosphorylated eIF-2 forms an inactive complex with another protein, called eIF2B, to reduce protein synthesis within the cell. Another cellular enzyme, RNAse L—also induced by interferon action—destroys RNA within the cells to further reduce protein synthesis of both viral and host genes. Inhibited protein synthesis destroys both the virus and infected host cells. In addition, interferons induce production of hundreds of other proteins—known collectively as interferon-stimulated genes (ISGs)—that have roles in combating viruses and other actions produced by interferon.^[9][10] They also limit viral spread by increasing p53 activity, which kills virus-infected cells by promoting apoptosis.^[11][12] The effect of IFN on p53 is also linked to its protective role against certain cancers.^[11]

Another function of interferons is to upregulate major histocompatibility complex molecules, MHC I and MHC II, and increase immunoproteasome activity. Higher MHC I expression increases presentation of viral peptides to cytotoxic T cells, while the immunoproteasome processes viral peptides for loading onto the MHC I molecule, thereby increasing the recognition and killing of infected cells. Higher MHC II expression increases presentation of viral peptides to helper T cells; these cells release cytokines (such as more interferons and interleukins, among others) that signal to and co-ordinate the activity of other immune cells.

Interferons, such as interferon gamma, directly activate other immune cells, such as macrophages and natural killer cells.

Induction of interferons

Production of interferons occurs mainly in response to microbes, such as viruses and bacteria, and their products. Binding of molecules uniquely found in microbes—viral glycoproteins, viral RNA, bacterial endotoxin (lipopolysaccharide), bacterial flagella, CpG motifs—by pattern recognition receptors, such as membrane bound Toll like receptors or the cytoplasmic receptors RIG-I or MDA5, can trigger release of IFNs. Toll Like Receptor 3 (TLR3) is important for inducing interferons in response to the presence of double-stranded RNA viruses; the ligand for this receptor is double-stranded RNA (dsRNA). After binding dsRNA, this receptor activates the transcription factors IRF3 and NF-κB, which are important for initiating synthesis of many inflammatory proteins. RNA interference technology tools such as siRNA or vector-based reagents can either silence or stimulate interferon pathways.^[13] Release of IFN from cells (specifically IFN-γ in lymphoid cells) is also induced by mitogens. Other cytokines, such as interleukin 1, interleukin 2, interleukin-12, tumor necrosis factor and colony-stimulating factor, can also enhance interferon production.^[14]

Downstream signaling

By interacting with their specific receptors, IFNs activate signal transducer and activator of transcription (STAT) complexes; STATs are a family of transcription factors that regulate the expression of certain immune system genes. Some STATs are activated by both type I and type II IFNs. However each IFN type can also activate unique STATs.^[15]

STAT activation initiates the most well-defined cell signaling pathway for all IFNs, the classical Janus kinase-STAT (JAK-STAT) signaling pathway.^[15] In this pathway, JAKs associate with IFN receptors and, following receptor engagement with IFN, phosphorylate both STAT1 and STAT2. As a result, an IFN-stimulated gene factor 3 (ISGF3) complex forms—this contains STAT1, STAT2 and a third transcription factor called IRF9—and moves into the cell nucleus. Inside the nucleus, the ISGF3 complex binds to specific nucleotide sequences called IFN-stimulated response elements (ISREs) in the promoters of certain genes, known as IFN stimulated genes ISGs. Binding of ISGF3 and other transcriptional complexes activated by IFN signaling to these specific regulatory elements induces transcription of those genes.^[15] A collection of known ISGs is available on Interferome, a curated online database of ISGs (www.interferome.org);^[16] Additionally, STAT homodimers or heterodimers form from different combinations of STAT-1, -3, -4, -5, or -6 during IFN signaling; these dimers initiate gene transcription by binding to IFN-activated site (GAS) elements in gene promoters.^[15] Type I IFNs can induce expression of genes with either ISRE or GAS elements, but gene induction by type II IFN can occur only in the presence of a GAS element.^[15]

In addition to the JAK-STAT pathway, IFNs can activate several other signaling cascades. For instance, both type I and type II IFNs activate a member of the CRK family of adaptor proteins called CRKL, a nuclear adaptor for STAT5 that also regulates signaling through the C3G/Rap1 pathway.^[15] Type I IFNs further activate p38 mitogen-activated protein kinase (MAP kinase) to induce gene transcription.^[15] Antiviral and antiproliferative effects specific to type I IFNs result from p38 MAP kinase signaling. The phosphatidylinositol 3-kinase (PI3K) signaling pathway is also regulated by both type I and type II IFNs. PI3K activates P70-S6 Kinase 1, an enzyme that increases protein synthesis and cell proliferation; phosphorylates of ribosomal protein s6, which is involved in protein synthesis; and phosphorylates a translational repressor protein called eukaryotic translation-initiation factor 4E-binding protein 1 (EIF4EBP1) in order to deactivate it.^[15]

Virus resistance to interferons

Many viruses have evolved mechanisms to resist interferon activity.^[17] They circumvent the IFN response by blocking downstream signaling events that occur after the cytokine binds to its receptor, by preventing further IFN production, and by inhibiting the functions of proteins that are induced by IFN.^[18] Viruses that inhibit IFN signaling include Japanese Encephalitis Virus (JEV), dengue type 2 virus (DEN-2) and viruses of the herpesvirus family, such as human cytomegalovirus (HCMV) and Kaposi's sarcoma-associated herpesvirus (KSHV or HHV8).^[18][19] Viral proteins proven to affect IFN signaling include EBV nuclear antigen 1 (EBNA1) and EBV nuclear antigen 2 (EBNA-2) from Epstein-Barr virus, the large T antigen of Polyomavirus, the E7 protein of Human papillomavirus (HPV), and the B18R protein of vaccinia virus.^[19][20] Reducing IFN-α activity may prevent signaling via STAT1, STAT2, or IRF9 (as with JEV infection) or through the JAK-STAT pathway (as with DEN-2 infection).^[18] Several poxviruses encode soluble IFN receptor homologs—like the B18R protein of the vaccinia virus—that bind to and prevent IFN interacting with its cellular receptor, impeding communication between this cytokine and its target cells.^[20] Some viruses can encode proteins that bind to double-stranded RNA (dsRNA) to prevent the activity of RNA-dependent protein kinases; this is the mechanism reovirus adopts using its sigma 3 (σ3) protein, and vaccinia virus employs using the gene product of its E3L gene, p25.^[21][22][23] The ability of interferon to induce protein production from interferon stimulated genes (ISGs) can also be affected. Production of protein kinase R, for example, can be disrupted in cells infected with JEV ^[18] Some viruses escape the anti-viral activities of interferons by gene (and thus protein) mutation. The H5N1 influenza virus, also known as bird flu, has resistance to interferon and other anti-viral cytokines that is attributed to a single amino acid change in its Non-Structural Protein 1 (NS1), although the precise mechanism of how this confers immunity is unclear.^[24]

Interferon therapy

Three vials filled with human leukocyte interferon

Diseases

Interferon beta-1a and interferon beta-1b are used to treat and control multiple sclerosis, an autoimmune disorder. This treatment is effective for reducing attacks in relapsing-remitting multiple sclerosis and slowing disease progression and activity in secondary progressive multiple sclerosis.^[25]

Interferon therapy is used (in combination with chemotherapy and radiation) as a treatment for some cancers.^[26] This treatment can be used in hematological malignancy; leukemia and lymphomas including hairy cell leukemia, chronic myeloid leukemia, nodular lymphoma, and cutaneous T-cell lymphoma.^[26] Patients with recurrent melanomas receive recombinant IFN-α2b.^[27] Both hepatitis B and hepatitis C are treated with IFN-α, often in combination with other antiviral drugs.^[28][29] Some of those treated with interferon have a sustained virological response and can eliminate hepatitis virus. The most harmful strain—hepatitis C genotype I virus—can be treated with a 60-80% success rate with the current standard-of-care treatment of interferon-α, ribavirin and recently approved protease inhibitors such as Telaprevir (Incivek) May 2011, Boceprevir (Victrelis) May 2011 or the nucleotide analog polymerase inhibitor Sofosbuvir (Sovaldi) December 2013.^[30] Biopsies of patients given the treatment show reductions in liver damage and cirrhosis. Some evidence shows giving interferon immediately following infection can prevent chronic hepatitis C, although diagnosis early in infection is difficult since physical symptoms are sparse in early hepatitis C infection. Control of chronic hepatitis C by IFN is associated with reduced hepatocellular carcinoma.^[31]

Interferon treatment was evaluated in individuals suffering from herpes simplex virus epithelial keratitis. Topical interferon therapy was shown to be an effective treatment, especially with higher concentrations.^[32] Interferon, either used alone or in combination with debridement, appears to be as effective as a nucleoside antiviral agent.^[32] The combination of interferon and another nucleoside antiviral agent may speed the healing process.^[32]

When used in the systemic therapy, IFNs are mostly administered by an intramuscular injection. The injection of IFNs in the muscle or under skin is generally well tolerated. The most frequent adverse effects are flu-like symptoms: increased body temperature, feeling ill, fatigue, headache, muscle pain, convulsion, dizziness, hair thinning, and depression. Erythema, pain and hardness on the spot of injection are also frequently observed. IFN therapy causes immunosuppression, in particular through neutropenia and can result in some infections manifesting in unusual ways.^[33]

Drug formulations

Pharmaceutical forms of interferons

Generic name	Trade name
Interferon alpha 2a	Roferon A
Interferon alpha 2b	Intron A/Reliferon/Uniferon
Human leukocyte Interferon-alpha (HuIFN-alpha-Le)	Multiferon
Interferon beta 1a, liquid form	Rebif
Interferon beta 1a, lyophilized	Avonex
Interferon beta 1a, biogeneric (Iran)	Cinnovex
Interferon beta 1b	Betaseron / Betaferon
Interferon gamma 1b	Actimmune
PEGylated interferon alpha 2a	Pegasys
PEGylated interferon alpha 2a (Egypt)	Reiferon Retard
PEGylated interferon alpha 2b	PegIntron
PEGylated interferon alpha 2b plus ribavirin (Canada)	Pegetron

Several different types of interferons are approved for use in humans. One was first approved for medical use in 1986.^[34] For example, in January 2001, the Food and Drug Administration (FDA) approved the use of PEGylated interferon-alpha in the USA; in this formulation, PEGylated interferon-alpha-2b (Pegintron), polyethylene glycol is linked to the interferon molecule to make the interferon last longer in the body. Approval for PEGylated interferon-alpha-2a (Pegasys) followed in October 2002. These PEGylated drugs are injected once weekly, rather than administering two or three times per week, as is necessary for conventional interferon-alpha. When used with the antiviral drug ribavirin, PEGylated interferon is effective in treatment of hepatitis C; at least 75% of people with hepatitis C genotypes 2 or 3 benefit from interferon treatment, although this is effective in less than 50% of people infected with genotype 1 (the more common form of hepatitis C virus in both the U.S. and Western Europe).^[35][36][37] Interferon-containing regimens may also include protease inhibitors such as boceprevir and telaprevir.

History

Sidney Pestka of Rutgers University, seen here receiving the National Medal of Technology.

Interferons were first described in 1957 by Alick Isaacs and Jean Lindenmann at the National Institute for Medical Research in London;^[38][39][40] the discovery was a result of their studies of viral interference. Viral interference refers to the inhibition of virus growth caused by previous exposure of cells to an active or a heat-inactivated virus. Isaacs and Lindenmann were working with a system that involved the inhibition of the growth of live influenza virus in chicken embryo chorioallantoic membranes by heat-inactivated influenza virus. Their experiments revealed that this interference was mediated by a protein released by cells in the heat-inactivated influenza virus-treated membranes. They published their results in 1957 naming the antiviral factor they had discovered interferon.^[39] The findings of Isaacs and Lindenmann have been widely confirmed and corroborated in the literature.^[41]

Furthermore, others may have made observations on interferons before the 1957 publication of Isaacs and Lindenmann. For example, during research to produce a more efficient vaccine for smallpox, Yasu-ichi Nagano and Yasuhiko Kojima—two Japanese virologists working at the Institute for Infectious Diseases at the University of Tokyo—noticed inhibition of viral growth in an area of rabbit-skin or testis previously inoculated with UV-inactivated virus. They hypothesised that some "viral inhibitory factor" was present in the tissues infected with virus and attempted to isolate and characterize this factor from tissue homogenates.^[42] Independently, Monto Ho, in John Enders's lab, observed in 1957 that attenuated poliovirus conferred a species specific anti-viral effect in human amniotic cell cultures. They described these observations in a 1959 publication, naming the responsible factor viral inhibitory factor (VIF).^[43] It took another fifteen to twenty years, using somatic cell genetics, to show that the interferon action gene and interferon gene reside in different human chromosomes.^[44][45][46] The purification of human beta interferon did not occur until 1977. Chris Y.H. Tan and his co-workers purified and produced biologically active, radio-labeled human beta interferon by superinducing the interferon gene in fibroblast cells, and they showed its active site contains tyrosine residues.^[47][48] Tan's laboratory isolated sufficient amounts of human beta interferon to perform the first amino acid, sugar composition and N-terminal analyses.^[49] They showed that human beta interferon was an unusually hydrophobic glycoprotein. This explained the large loss of interferon activity when preparations were transferred from test tube to test tube or from vessel to vessel during purification. The analyses showed the reality of interferon activity by chemical verification.^{[49][50][51][52]} The purification of human alpha interferon was not reported until 1978. A series of publications from the laboratories of Sidney Pestka and Alan Waldman between 1978 and 1981, describe the purification of the type I interferons IFN-α and IFN-β.^[40] By the early 1980s, genes for these interferons had been cloned, adding further definitive proof that interferons were responsible for interfering with viral replication.^[53][54] Gene cloning also confirmed that IFN-α was encoded by a family of many related genes.^[55] The type II IFN (IFN-γ) gene was also isolated around this time.^[56]

Interferon was scarce and expensive until 1980, when the interferon gene was inserted into bacteria using recombinant DNA technology, allowing mass cultivation and purification from bacterial cultures^[57] or derived from yeasts. Interferon can also be produced by recombinant mammalian cells.^[58] Before the early 1970s, large scale production of human interferon had been pioneered by Kari Cantell. He produced large amounts of human alpha interferon from large quantities of human white blood cells collected by the Finnish Blood Bank.^[59] Large amounts of human beta interferon were made by superinducing the beta interferon gene in human fibroblast cells.^[60][61]

Cantell's and Tan's methods of making large amounts of natural interferon were critical for chemical characterisation, clinical trials and the preparation of small amounts of interferon messenger RNA to clone the human alpha and beta interferon genes. The superinduced human beta interferon messenger RNA was prepared by Tan's lab for Cetus corp. to clone the human beta interferon gene in bacteria and the recombinant interferon was developed as 'betaseron' and approved for the treatment of MS. Superinduction of the human beta interferon gene was also used by Israeli scientists to manufacture human beta interferon.

Human interferons

• IFNA1
• IFNA2
• IFNA4
• IFNA5
• IFNA6
• IFNA7
• IFNA8
• IFNA10
• IFNA13
• IFNA14
• IFNA16
• IFNA17
• IFNA21
• IFNB1
• IFNW
• IFNE1
• IFNK

^[4][62]

See also

• ATC code L03#L03AB Interferons
• Immunosuppression
• Immunosuppressive drug
• Immunotherapy
• Interferon Consensus Sequence-binding protein

References

1. De Andrea, M; Gariglio, M; Gioia, D; Landolfo, S; Ravera, R (2002). "The interferon system: an overview". Eur J Paediatr Neurol. 6 Suppl A (6): A41–58. PMID 12365360.
2. Cohen, B; Parkin, J (2001). "An overview of the immune system". Lancet. 357 (9270): 1777–89. doi:10.1016/S0140-6736(00)04904-7. ISSN 0140-6736.
3. De Weerd NA, Samarajiwa SA, Hertzog PJ (2007). "Type I interferon receptors: biochemistry and biological functions". J Biol Chem. 282 (28): 20053–20057. doi:10.1074/jbc.R700006200. PMID 17502368.
4. Liu, YJ (2005). "IPC: professional type 1 interferon-producing cells and plasmacytoid dendritic cell precursors". Annu Rev Immunol. 23: 275–306. doi:10.1146/annurev.immunol.23.021704.115633. PMID 15771572.
5. Kidd, P. "Th1/Th2 Balance: the hypothesis, its limitations, and implications for health and disease". Alternative Medicine Review. 8: 223–46.
6. Ivashkiv, LB; Kalliolias, GD (2010). "Overview of the biology of type I interferons". Arthritis Research & Therapy. 12 (Suppl 1): S1. doi:10.1186/ar2881.
7. Vilcek, Novel interferons, Nature Immunol. 4, 8-9. 2003
8. Hermant, P, Michiels, T., Interferon-λ in the Context of Viral Infections: Production, Response and Therapeutic Implications.J Innate Immun (2014) Apr. 17
9. Fensterl V, Sen GC (2009). "Interferons and viral infections". BioFactors. 35 (1): 14–20. doi:10.1002/biof.6. PMID 19319841.
10. De Veer MJ, Holko M, Frevel M, Walker E, Der S, Paranjape JM, Silverman RH, Williams BR (2001). "Functional classification of interferon-stimulated genes identified using microarrays". Journal of leukocyte biology. 69 (6): 912–20. PMID 11404376.
11. Takaoka A, Hayakawa S, Yanai H, Stoiber D, Negishi H, Kikuchi H, Sasaki S, Imai K, Shibue T, Honda K, Taniguchi T (2003). "Integration of interferon-alpha/beta signalling to p53 responses in tumour suppression and antiviral defence" (PDF). Nature. 424 (6948): 516–23. Bibcode:2003Natur.424..516T. doi:10.1038/nature01850. PMID 12872134.
12. Moiseeva O, Mallette FA, Mukhopadhyay UK, Moores A, Ferbeyre G (2006). "DNA Damage Signaling and p53-dependent Senescence after Prolonged β-Interferon Stimulation". Mol. Biol. Cell. 17 (4): 1583–92. doi:10.1091/mbc.E05-09-0858. PMC 1415317. PMID 16436515.
13. Whitehead KA, Dahlman JE, Langer RS, Anderson DG (2011). "Silencing or stimulation? siRNA delivery and the immune system". Annu Rev Chem Biomol Eng. 2: 77–96. doi:10.1146/annurev-chembioeng-061010-114133. PMID 22432611.
14. Haller O, Kochs G, Weber F (October–December 2007). "Interferon, Mx, and viral countermeasures". Cytokine Growth Factor Rev. 18 (5–6): 425–33. doi:10.1016/j.cytogfr.2007.06.001. PMID 17683972.
15. Platanias LC (May 2005). "Mechanisms of type-I- and type-II-interferon-mediated signalling". Nature reviews. Immunology. 5 (5): 375–386. doi:10.1038/nri1604. PMID 15864272.
16. Samarajiwa SA, Forster S, Auchettl K, Hertzog PJ (January 2009). "INTERFEROME: the database of interferon regulated genes.". Nucleic Acids Res. 37: D852–7. doi:10.1093/nar/gkn732. PMC 2686605. PMID 18996892.
17. Navratil V, de Chassey B, Meyniel L, Pradezynski F, André P, Rabourdin-Combe C, Lotteau V (2010-11-05). "Systems-level comparison of protein-protein interactions between viruses and the human type I interferon system network". Journal of Proteome Research. 9 (7): 3527–36. doi:10.1021/pr100326j. PMID 20459142.
18. Lin RJ, Liao CL, Lin E, Lin YL (September 2004). "Blocking of the Alpha Interferon-Induced Jak-Stat Signaling Pathway by Japanese Encephalitis Virus Infection". J. Virol. 78 (17): 9285–94. doi:10.1128/JVI.78.17.9285-9294.2004. PMC 506928. PMID 15308723.
19. Sen GC (2001). "Viruses and interferons". Annu. Rev. Microbiol. 55: 255–81. doi:10.1146/annurev.micro.55.1.255. PMID 11544356.
20. Alcamí A, Symons JA, Smith GL (December 2000). "The Vaccinia virus soluble Alpha/Beta interferon (IFN) receptor binds to the cell surface and protects cells from the antiviral effects of IFN". J. Virol. 74 (23): 11230–9. doi:10.1128/JVI.74.23.11230-11239.2000. PMC 113220. PMID 11070021.
21. Minks MA, West DK, Benvin S, Baglioni C (October 1979). "Structural requirements of double-stranded RNA for the activation of 2',5'-oligo(A) polymerase and protein kinase of interferon-treated HeLa cells". J. Biol. Chem. 254 (20): 10180–3. PMID 489592.
22. Miller JE, Samuel CE (September 1992). "Proteolytic cleavage of the reovirus sigma 3 protein results in enhanced double-stranded RNA-binding activity: identification of a repeated basic amino acid motif within the C-terminal binding region". J. Virol. 66 (9): 5347–56. PMC 289090. PMID 1501278.
23. Chang HW, Watson JC, Jacobs BL (June 1992). "The E3L gene of vaccinia virus encodes an inhibitor of the interferon-induced, double-stranded RNA-dependent protein kinase". Proc. Natl. Acad. Sci. U.S.A. 89 (11): 4825–9. Bibcode:1992PNAS...89.4825C. doi:10.1073/pnas.89.11.4825. PMC 49180. PMID 1350676.
24. Seo SH, Hoffmann E, Webster RG (August 2002). "Lethal H5N1 influenza viruses escape host anti-viral cytokine responses". Nature Medicine. 8 (9): 950–954. doi:10.1038/nm757. PMID 12195436.
25. Paolicelli D, Direnzo V, Trojano M (14 September 2009). "Review of interferon beta-1b in the treatment of early and relapsing multiple sclerosis". Biologics: Targets & Therapy. 3: 369–376. PMC 2726074. PMID 19707422.
26. Goldstein D, Laszlo J (Sep 1988). "The role of interferon in cancer therapy: a current perspective" (Free full text). CA: A Cancer Journal for Clinicians. 38 (5): 258–277. doi:10.3322/canjclin.38.5.258. PMID 2458171.
27. Hauschild A, Gogas H, Tarhini A, Middleton MR, Testori A, Dréno B, Kirkwood JM (Mar 2008). "Practical guidelines for the management of interferon-alpha-2b side effects in patients receiving adjuvant treatment for melanoma: expert opinion". Cancer. 112 (5): 982–994. doi:10.1002/cncr.23251. PMID 18236459.
28. Cooksley WG (Mar 2004). "The role of interferon therapy in Hepatitis B". MedGenMed : Medscape general medicine. 6 (1): 16. PMC 1140699. PMID 15208528.
29. Shepherd J, Waugh N, Hewitson P (2000). "Combination therapy (interferon alfa and ribavirin) in the treatment of chronic hepatitis C: a rapid and systematic review" (Free full text). Health technology assessment (Winchester, England). 4 (33): 1–67. PMID 11134916.
30. Ge D, Fellay J, Thompson AJ, Simon JS, Shianna KV, Urban TJ, Heinzen EL, Qiu P, Bertelsen AH, Muir AJ, Sulkowski M, McHutchison JG, Goldstein DB (2009). "Genetic variation in IL28B predicts hepatitis C treatment-induced viral clearance". Nature. 461 (7262): 399–401. Bibcode:2009Natur.461..399G. doi:10.1038/nature08309. PMID 19684573.
31. Ishikawa T (Oct 2008). "Secondary prevention of recurrence by interferon therapy after ablation therapy for hepatocellular carcinoma in chronic hepatitis C patients" (Free full text). World Journal of Gastroenterology. 14 (40): 6140–6144. doi:10.3748/wjg.14.6140. PMC 2761574. PMID 18985803.
32. Wilhelmus KR (2010). "Antiviral treatment and other therapeutic interventions for herpes simplex virus epithelial keratitis". Cochrane Database Syst Rev. 12: CD002898. doi:10.1002/14651858.CD002898.pub4. PMC 4739528. PMID 21154352.
33. Bhatti Z, Berenson CS (2007). "Adult systemic cat scratch disease associated with therapy for hepatitis C". BMC Infect Dis. 7: 8. doi:10.1186/1471-2334-7-8. PMC 1810538. PMID 17319959.
34. Long, Sarah S.; Pickering, Larry K.; Prober, Charles G. (2012). Principles and Practice of Pediatric Infectious Disease. Elsevier Health Sciences. p. 1502. ISBN 1437727026.
35. Jamall IS, Yusuf S, Azhar M, Jamall S (2008). "Is pegylated interferon superior to interferon, with ribavarin, in chronic hepatitis C genotypes 2/3?". World J. Gastroenterol. 14 (43): 6627–31. doi:10.3748/wjg.14.6627. PMC 2773302. PMID 19034963.
36. "NIH Consensus Statement on Management of Hepatitis C: 2002". NIH Consens State Sci Statements. 19 (3): 1–46. 2002. PMID 14768714.
37. Sharieff KA, Duncan D, Younossi Z (February 2002). "Advances in treatment of chronic hepatitis C: 'pegylated' interferons". Cleve Clin J Med. 69 (2): 155–9. doi:10.3949/ccjm.69.2.155. PMID 11990646.
38. Kolata, Gina (2015-01-22). "Jean Lindenmann, Who Made Interferon His Life's Work, Is Dead at 90". New York Times. Retrieved 2015-02-12.
39. Isaacs, A; Lindenmann, J (September 1957). "Virus interference. I. The interferon". Proc. R. Soc. Lond., B, Biol. Sci. 147 (927): 258–67. Bibcode:1957RSPSB.147..258I. doi:10.1098/rspb.1957.0048. PMID 13465720.
40. Pestka, S (2007). "The interferons: 50 years after their discovery, there is much more to learn". J. Biol. Chem. 282 (28): 20047–51. doi:10.1074/jbc.R700004200. PMID 17502369.
41. Stewart II, WE, The Interferon System. Springer Veralg. Vienna 1979.
42. Nagano Y, Kojima Y (October 1954). "Pouvoir immunisant du virus vaccinal inactivé par des rayons ultraviolets". C. R. Seances Soc. Biol. Fil. (in French). 148 (19–20): 1700–2. PMID 14364998.
43. Ho, M, and Enders, JF, An inhibitor of viral activity appearing in infected cell cultures. PNAS 45, 385-389, 1959
44. Tan YH, Tischfield J, Ruddle FH (1973). "The linkage of genes for the human interferon-induced antiviral protein and indophenol oxidase-B traits to chromosome G-21". J. Exp. Med. 137 (2): 317–30. doi:10.1084/jem.137.2.317. PMC 2139494. PMID 4346649.
45. Tan YH (1976). "Chromosome 21 and the cell growth inhibitory effect of human interferon preparations". Nature. 260 (5547): 141–3. doi:10.1038/260141a0. PMID 176593.
46. Meager A, Graves H, Burke DC, Swallow DM (1979). "Involvement of a gene on chromosome 9 in human fibroblast interferon production". Nature. 280 (5722): 493–5. doi:10.1038/280493a0. PMID 460428.
47. Berthold W, Tan C, Tan YH (1978). "Chemical modifications of tyrosyl residue(s) and action of human-fibroblast interferon". Eur. J. Biochem. 87 (2): 367–70. doi:10.1111/j.1432-1033.1978.tb12385.x. PMID 678325.
48. Berthold W, Tan C, Tan YH (1978). "Purification and in vitro labeling of interferon from a human fibroblastoid cell line". J. Biol. Chem. 253 (14): 5206–12. PMID 670186.
49. Tan YH, Barakat F, Berthold W, Smith-Johannsen H, Tan C (1979). "The isolation and amino acid/sugar composition of human fibroblastoid interferon". J. Biol. Chem. 254 (16): 8067–73. PMID 468807.
50. Zoon KC, Smith ME, Bridgen PJ, Anfinsen CB, Hunkapiller MW, Hood LE (1980). "Amino terminal sequence of the major component of human lymphoblastoid interferon". Science. 207 (4430): 527–8. doi:10.1126/science.7352260. PMID 7352260.
51. Okamura H, Berthold W, Hood L, Hunkapiller M, Inoue M, Smith-Johannsen H, Tan YH (1980). "Human fibroblastoid interferon: immunosorbent column chromatography and N-terminal amino acid sequence". Biochemistry. 19 (16): 3831–5. doi:10.1021/bi00557a028. PMID 6157401.
52. Knight E, Hunkapiller MW, Korant BD, Hardy RW, Hood LE (1980). "Human fibroblast interferon: amino acid analysis and amino terminal amino acid sequence". Science. 207 (4430): 525–6. doi:10.1126/science.7352259. PMID 7352259.
53. Weissenbach J, Chernajovsky Y, Zeevi M, Shulman L, Soreq H, Nir U, Wallach D, Perricaudet M, Tiollais P, Revel M (December 1980). "Two interferon mRNAs in human fibroblasts: in vitro translation and Escherichia coli cloning studies". Proc. Natl. Acad. Sci. U.S.A. 77 (12): 7152–6. Bibcode:1980PNAS...77.7152W. doi:10.1073/pnas.77.12.7152. PMC 350459. PMID 6164058.
54. Taniguchi T, Fujii-Kuriyama Y, Muramatsu M (July 1980). "Molecular cloning of human interferon cDNA". Proc. Natl. Acad. Sci. U.S.A. 77 (7): 4003–6. Bibcode:1980PNAS...77.4003T. doi:10.1073/pnas.77.7.4003. PMC 349756. PMID 6159625.
55. Nagata S, Mantei N, Weissmann C (October 1980). "The structure of one of the eight or more distinct chromosomal genes for human interferon-alpha". Nature. 287 (5781): 401–8. Bibcode:1980Natur.287..401N. doi:10.1038/287401a0. PMID 6159536.
56. Gray PW, Goeddel DV (August 1982). "Structure of the human immune interferon gene". Nature. 298 (5877): 859–63. Bibcode:1982Natur.298..859G. doi:10.1038/298859a0. PMID 6180322.
57. Nagata S, Taira H, Hall A, Johnsrud L, Streuli M, Ecsödi J, Boll W, Cantell K, Weissmann C (March 1980). "Synthesis in E. coli of a polypeptide with human leukocyte interferon activity". Nature. 284 (5754): 316–20. Bibcode:1980Natur.284..316N. doi:10.1038/284316a0. PMID 6987533.
58. US patent 6207146, Tan YH, Hong WJ, "Gene expression in mammalian cells.", issued 2001 
59. Cantell K (1998). The story of interferon: the ups and downs in the life of a scientis. Singapore ; New York: World Scientific. ISBN 978-981-02-3148-4.
60. Tan YH, Armstrong JA, Ke YH, Ho M (1970). "Regulation of cellular interferon production: enhancement by antimetabolites". Proc. Natl. Acad. Sci. U.S.A. 67 (1): 464–71. doi:10.1073/pnas.67.1.464. PMC 283227. PMID 5272327.
61. US patent 3773924, Ho M, Armstrong JA, Ke YH, Tan YH, "Interferon Production", issued 1973 
62. Bekisz, J; Goldman, ND; Hernandez, J; Schmeisser, H; Zoon, KC (2004). "Mini Review Human Interferons Alpha, Beta and Omega". Growth Factors. 22 (4): 243–51. doi:10.1080/08977190400000833. PMID 15621727.