Interferon preparations

Classification and production methods

In medical practice, interferon (IFN) preparations are classified according to two main criteria: chemical-biological properties and production technology.

Based on chemical and biological properties, six types are distinguished. The most clinically significant are IFN-α (alpha), IFN-β (beta), and IFN-γ (gamma). There are also IFN-δ (delta), IFN-ω (omega), and IFN-τ (tau).

According to the production method, there are two major groups of dosage forms:

• Natural preparations. These are obtained from a culture of leukocytes isolated from donor blood. To trigger interferon synthesis, the cells are induced with a specific virus. This group includes IFN-α, IFN-β, as well as IFN-α-n1.
• Recombinant preparations. These are the product of modern genetic engineering. Under laboratory conditions, a plasmid containing the human interferon gene is inserted into bacterial strains, after which the bacteria begin to synthesize the desired glycoprotein. Examples of such agents include IFN-α-2a, IFN-α-2b, and IFN-α-1b.

Pharmacokinetics and mechanism of action

The pharmacokinetics of interferons has strict limitations. These drugs are completely inactive when administered orally, as their protein structure is rapidly destroyed in the gastrointestinal tract. Therefore, they are administered exclusively parenterally (subcutaneously, intramuscularly, or intravenously) or applied topically.

The initial stage of the drug's action consists in the interaction of the molecule with specific receptors located on the membrane of target cells. This binding triggers a complex cascade of intracellular reactions, which leads to the induction of the synthesis of various enzymes.

At the cellular level, interferons exert three main effects: antiviral, antitumor, and immunomodulating.

• Antiviral mechanism: interferon activates a specific enzyme that directly inhibits (blocks) the translation of viral RNA. This prevents further replication of the virus inside the cell.
• Effect on the cell cycle: the drugs exercise strict control over cell proliferation (division), regulate their differentiation, and can trigger apoptosis (programmed cell death) of defective structures.
• Immune response: activation of immune effectors—macrophages—occurs, as well as a significant increase in the cytotoxicity of lymphocytes.

Clinical application

Indications for prescription depend on the specific type of interferon and its dosage form.

1. IFN-α (alpha) preparations have the broadest spectrum of applications. In infectiology, they are prescribed for viral hepatitis B and C, HIV infection, and papillomavirus infection. In oncology practice, they have proven effective in treating Kaposi's sarcoma, various leukemias, and melanoma.
2. IFN-β (beta) preparations have found their niche in neurology. They are used as powerful immunomodulators in the combination therapy of multiple sclerosis.
3. IFN-γ (gamma) preparations (e.g., Ingaron) are used to treat severe pathologies, specifically chronic granulomatous disease.
4. Local and topical application covers different types of IFN:
5. Ophthalmology: treatment of herpetic eye lesions (drops and subconjunctival injections are used).
6. Dermatovenereology: therapy of herpes simplex (localized on the skin, mucous membranes, and genitals) and herpes zoster. Special hydrogel-based ointments are used for this purpose.
7. Respiratory infections: prevention and treatment of influenza and ARVI using intranasal drops.

Side effects

Despite high efficacy, interferon therapy is characterized by a wide range of side effects. The most frequent adverse event is influenza-like syndrome.

In addition, the drugs can have a negative impact on various organ systems:

• Central nervous system (CNS): patients often complain of dizziness, visual disturbances, insomnia, and tremor. In severe cases, confusion, depression, and paresthesia may occur.
• Gastrointestinal tract (GI): nausea and pronounced loss of appetite are characteristic.
• Hematopoiesis and kidneys: transient leukopenia and proteinuria may be observed in laboratory tests.
• Cardiovascular system: symptoms of heart failure may appear.
• Other reactions: dermatological manifestations (skin rash, itching, alopecia), nosebleeds, and temporary impotence.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• The process of obtaining natural interferons from a donor leukocyte culture.
• The technology of cultivating bacterial strains to produce recombinant IFNs.
• Mechanisms of cell cycle control, proliferation, and apoptosis initiation.
• Specific enzymes inhibiting viral RNA translation.
• Use of IFN-alpha preparations in oncology (melanoma, Kaposi sarcoma, leukemias).

Other topics in the section "Agents Regulating Immune Processes"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.