Interferon

Interferonum

For medical students3 min readUpdated 2026-10-10

Interferons are a group of drugs that affect immune processes and suppress inflammation. They represent a family of small regulatory glycoproteins (cytokines) with pronounced antiviral, immunomodulating, and antiproliferative activities.

Pharmacological groupCytokines, immunomodulators, and antiviral agents

Main mechanismBlockade of viral RNA translation inside the cell

Routes of administrationParenteral and topical (completely destroyed in the gastrointestinal tract)

Frequent adverse effectFlu-like syndrome

Mechanism of Action

The action of interferons (IFNs) begins with their binding to specific receptors located on the cell membrane. This binding triggers a complex cascade of intracellular reactions leading to the induction of various enzymes responsible for the drug's biological effects.

The antiviral mechanism is mediated through the activation of specific enzymes that inhibit (block) viral RNA translation. As a result, the virus loses its ability to replicate inside the infected cell. At the cellular level, these drugs also actively interfere with the cell cycle, ensuring strict control over proliferation, cell differentiation, and apoptosis.

Pharmacological Effects

This drug group is characterized by the classic triad of main effects:

Antiviral — protection of cells from viral entry and replication.
Immunomodulatory — formation and modulation of the immune response. This involves the activation of immune effectors such as macrophages, as well as an increase in lymphocyte cytotoxicity.
Antitumor (antiproliferative) — suppression of excessive cell growth and regulation of the cell cycle.

Classification and Preparations

Based on chemical and biological properties, 6 types of interferons are distinguished: $\alpha$ (alpha), $\beta$ (beta), $\gamma$ (gamma), $\delta$ (delta), $\omega$ (omega), and $\tau$ (tau).

According to the production method (dosage forms), preparations are divided into two large groups:

Natural: obtained from donor blood leukocyte cultures via viral induction. Examples: Human leukocyte interferon (a mixture of IFN-$\alpha$ subtypes), Lokferon.
Recombinant: synthesized via genetic engineering (cultivation of bacterial strains with integrated human IFN gene plasmids). Examples: IFN-$\alpha$-2a (Roferon-A), IFN-$\alpha$-2b.

Note: The highly purified recombinant IFN-$\alpha$-2b protein structurally differs from IFN-$\alpha$-2a by the presence of the amino acid arginine at position 23.

Indications for Use

Clinical application strictly depends on the type of interferon and its dosage form:

IFN-$\alpha$ preparations: used systemically for viral hepatitis B and C, HIV infection, and human papillomavirus infection. In oncology, they are prescribed for Kaposi sarcoma, chronic myelogenous leukemia, multiple myeloma, and melanoma.
IFN-$\beta$ preparations: used as immunomodulators in the treatment of multiple sclerosis.
IFN-$\gamma$ preparations: (e.g., Ingaron) are used to treat chronic granulomatous disease.

Local and Topical Application:

Ophthalmology: viral conjunctivitis, keratitis, uveitis (adenoviral and herpetic infections). Eye drops are used (e.g., the combination drug Ophthalmoferon, containing IFN-$\alpha$-2a and diphenhydramine, providing additional anti-inflammatory and local anesthetic effects) or subconjunctival injections.
Dermatovenerology: herpes simplex and herpes zoster (hydrogel-based ointments are used).
Respiratory infections: prevention and treatment of influenza and acute respiratory viral infections (ARVI) (nasal drops).

Side Effects

Exogenous interferon therapy is characterized by a wide range of adverse reactions. The most common is flu-like syndrome.

Other systemic reactions:

CNS: dizziness, visual disturbances, confusion, depression, insomnia, tremor, paresthesias.
GI tract: loss of appetite, nausea.
Blood and kidneys: transient leukopenia, proteinuria.
Cardiovascular system: symptoms of heart failure.
Other: skin rash, itching, alopecia, epistaxis, temporary impotence.

Alternative approach: the use of interferon inducers. These are substances that stimulate the production of one's own (endogenous) interferon. Their advantage is that an autologous protein is synthesized without antigenicity (no antibodies are produced), and there is no risk of hyperinterferonemia.

Administration Features and Prescription

Interferon preparations are inactive when taken orally, as their protein structure is completely destroyed by gastrointestinal enzymes. Therefore, they are administered exclusively parenterally (subcutaneously, intramuscularly, intravenously) or topically (nasally, into the conjunctival sac, on the skin).

Prescription Example (lyophilized powder for nasal administration in ARVI):

Rp.: Interferoni 10,000 IU D.t.d. No. 10 in amp. S. Dissolve the contents of the ampoule ex tempore in 2 ml of 0.9% NaCl solution. Instill 5 drops nasally into both nasal passages.

Mnemonic

The triad of interferon effects: VIP (Viruses, Immunity, Proliferation) — antiviral, immunomodulating, and antiproliferative.

Frequently asked questions

What specific enzymes are synthesized in the cell under the action of interferons to ensure the antiviral effect?

Under the action of interferons, three key enzymes and proteins are synthesized in the cell to provide the antiviral effect:

2',5'-oligoadenylate synthetase — activates cellular endoribonuclease (RNase L), leading to the cleavage of viral RNAs.
Protein kinase R — phosphorylates translation initiation factor eIF-2, blocking the synthesis of viral and cellular proteins.
Mx protein — binds to the viral RNA polymerase, blocking its activity and halting replication.

Which drugs belong to the group of interferon inducers?

Interferon inducers include drugs that stimulate the production of endogenous interferon in the body:

Tilorone.
Meglumine acridonacetate (Cycloferon) — a low-molecular-weight interferon inducer with a combined mechanism of action.
Sodium oxodihydroacridinylacetate (Neovir).
Polyadenylic acid + polyuridylic acid (Kagocel).
Imidazolyl ethanamide pentanedioic acid (Ingavirin).

Which specific receptors and signaling pathways do interferons interact with on the cell membrane?

Interferons interact with specific membrane receptors and trigger intracellular signal transduction:

Type I interferon receptor (IFNAR) consists of two molecules: IFNAR1 and IFNAR2; type I interferons, including IFN-$\alpha$ and IFN-$\beta$, bind to it.
Interferon-gamma receptor — IFN$\gamma$R.
Type III interferon receptor is represented by IFNAR1 and IL10R2 molecules.

Signaling pathways:

For type I and III interferons, Jak1 and Tyk2 kinases, as well as STAT proteins, participate in signal transduction.
For IFN$\gamma$, the main STAT pathway involving Jak1, Jak2, and Src kinase, as well as the MAPK cascade, PI3K pathway, and the transcription factor NF-AT, have been described.

Why are interferon preparations not manufactured as oral tablets?

Interferons are glycoproteins. When taken orally, they are completely destroyed by proteolytic enzymes in the gastrointestinal tract and lose their activity.

What is the main advantage of interferon inducers over recombinant preparations?

Inducers stimulate the production of endogenous (own) interferon. It lacks antigenicity (the body does not produce antibodies against it), and there is no risk of developing hyperinterferonemia.

How does recombinant IFN-alpha-2b structurally differ from IFN-alpha-2a?

The main structural difference of the highly purified recombinant IFN-alpha-2b protein is the presence of the amino acid arginine at position 23.

How does the combination drug Ophthalmoferon exert a local anesthetic effect?

In addition to recombinant IFN-alpha-2a, Ophthalmoferon contains the antihistamine diphenhydramine, which provides additional anti-inflammatory and local anesthetic effects.

Go deeper

Molecular cascade of intracellular reactions following IFN binding to membrane receptors.
Mechanisms of flu-like syndrome and depression development during exogenous cytokine therapy.
Technology of recombinant interferon production: the role of bacterial strains and plasmids.
Comparative profile of IFN-alpha, IFN-beta, and IFN-gamma preparations by clinical application spectrum.
Classification and mechanisms of action of endogenous interferon inducers.