Recombinant interferons are a group of antiviral drugs used for therapeutic and prophylactic purposes. These biologically active proteins are synthesized naturally in human cells in response to the penetration of foreign agents. In modern medicine, these drugs are recognized as the most effective and safe for the treatment of viral diseases.
Classification
In microbiology, there are more than 20 types of interferons (IFN), which differ in properties and biological structure. Medicines based on them are classified as follows:
- By type of active ingredient: o alpha-interferon (or leukocyte); o beta-interferon (fibroblast); o gamma-interferon (immune); o lambda-interferon.
- According to the method of obtaining: o natural, obtained from human blood leukocytes; o recombinant human interferon, produced synthetically (by genetic engineering).
Alpha- and beta-interferons are combined into family Itype due to the similarity of their functions in the body and the same amino acid sequences. Gamma and lambda interferons are isolated into separate types II and III, respectively. The first generation of natural proteins had a big drawback - they required the use of scarce raw materials (donor blood) and a high degree of purification from foreign proteins. This led to their high cost and low efficiency. Recombinant alpha-interferons currently occupy a leading position among drugs of this type in terms of the degree of study and breadth of application in medical practice.
Features
In addition to the above classification, these proteins differ in subtypes. Thus, the category of recombinant alpha 2 interferons includes at least 24 subtypes that differ from each other in 24 genes. They are not completely identical in primary structure.
Unlike alpha interferons, beta modification is encoded by only one known gene. Both types of proteins are activated by viruses and use the same receptors in their mechanism of action on other cells.
The subtype of human recombinant interferon alpha-2b differs from alpha-2a by two amino acid residues in the structure. The rest of them (and there are more than a hundred in total) are the same. Therefore, the diseases for which they are used, as well as side effects, are the same, but the reaction of the body (production of antibodies) is different.
Leukocyte natural interferons are also classified according to the degree of purification:
- Native, characterized by shallow cleaning andas close as possible to the original raw material. They have the greatest potential for immunobiological effects.
- Concentrated, highly purified. They are used most often in cases where a large single dose must be administered. The homogeneity of the composition of these preparations reaches 90%.
- Combined. They are obtained with gentle cleaning methods. The presence of additional cytokines makes it difficult to standardize these substances. At the same time, due to this factor, they have a higher immunomodulatory effect, which contributes to the expansion of their scope.
Recombinant human interferon contains a monospecific protein. It belongs to one of the subtypes. Type b1a in preparations of recombinant alpha interferon is characterized by a glycosylated form (non-enzymatic addition of sugar residues to organic protein molecules), and b1b is non-glycolized. Such interferons are 98% homogeneous in composition.
These features of natural and artificially synthesized proteins determine the difference in their field of application. Recombinant interferons have predominant antiviral and antitumor activity. In natural it is immunomodulatory, and there is also a higher activity against bacterial and purulent-septic pathologies.
Recombinant interferon preparations
The most widely used of this group of medicines are the following:
- alpha 2a interferon: "Reaferon","Viferon", "Roferon", "Interal";
- alpha 2b interferon: "Intron-A", "Laifferon", "Peginterferon", "Infagel", Inrek;
- alpha 2c interferon: "Berofor";
- beta-interferon: "Interferon-beta-1a", "Fron", "Rebif", "Avonex", "Betaseron", "Betaferon";
- gamma-interferon: "Aktimmun", "Gammaferon", "Ingaron", "Imukin".
Diseases
Recombinant interferons are active in the treatment of diseases such as:
- dermatological pathologies: genital herpes, warts, condylomas, papillomatosis, shingles;
- ophthalmic diseases: inflammation of the cornea of the eye caused by herpetic or adenovirus infection (reduction in the duration of the disease, an increase in interrecurrent periods);
- acute infectious diseases of the upper respiratory tract: influenza, SARS (emergency prevention for persons at risk, as well as for medical purposes);
- pathologies of the hepatobiliary system: viral hepatitis B, C in acute and chronic form (pronounced clinical effect, mortality reduction up to 60%);
- AIDS: normalization of immunity, reduction in the severity of the disease in more than half of patients; reduced risk of AIDS-related Kaposi's sarcoma;
- other pathologies: CMVI (cytomegalovirus infection), which occurs against the background of immunodeficiency states (interferons are used for itsprevention), as well as after transplantation operations; sclerosing panencephalitis (inflammation of the brain).
These preparations are characterized by a universal spectrum of antiviral activity. Unlike chemotherapeutic agents, they do not lead to the emergence of resistant forms of pathogens, but affect the factors of innate, natural immunity.
Discovery history
Interferons were discovered almost 50 years ago. The first drugs were obtained from the blood of donors. To do this, blood cells were treated with viruses, after which they began to produce proteins with protective properties. The interferon obtained in this way was highly effective, but its production on a large scale was hampered by the scarcity of raw materials. For example, to obtain the volume of the drug needed to treat 1 cancer patient, it was necessary to collect blood from 200 donors.
In the mid-80s of the XX century, the first prerequisites for obtaining synthetic recombinant interferons arose. The rapid development of genetic engineering in these years led to the creation of a new technology - the introduction of the appropriate gene into colonies of Pseudomonas putida bacterial cells that can multiply rapidly. This allowed the synthesis of human recombinant alpha 2b interferon on an industrial scale. The first drug created in the USSR was named Reaferon.
In subsequent years, thorough animal studies were carried out on this drug onthe subject of teratogenic and toxic properties. Tests have confirmed its safety for the fetus and the absence of differences between the side effects of artificially synthesized and natural interferon.
Later, E. coli bacteria began to be used to obtain recombinant interferon, as they produce this substance faster. The first drug obtained on their basis was called "Reaferon-EC" (from the abbreviation of the Latin name of this microorganism Escherichia coli). These bacteria are also used in most modern production of recombinant interferons.
Operation principle
Interferons are a kind of biological mediators that activate the human immune system. They contribute to the recognition and suppression of alien genetic information. With the introduction of viruses into the cell, after a few minutes, the number of pathogens increases many times over. They spread further, affecting he althy cells and multiplying again. This process occurs especially quickly at the initial stage of the disease, since during this period the human body is not able to produce the required amount of interferon.
Thanks to these proteins, the synthesis of a number of enzymes, antibodies and other components of the immune defense is triggered. As a result, cells become immune to viruses. The following mechanisms are also distinguished, in which interferons are involved:
- stimulation of macrophages, their activation to absorb non-viable, affected cells;
- growth inhibition and destruction of abnormal cells(antitumor effect);
- impact on immunocytes (lymphocytes produced in the bone marrow) - the main cells of the immune system: NK cells, T-lymphocytes, monocytes, macrophages and granulocytes; stimulation of their non-specific cytotoxicity;
- activation of the synthesis of proteins that increase the resistance of cells to foreign agents, the transfer of these proteins to neighboring cells;
- starting a cascade of reactions that stimulate the production of anti-inflammatory factors (anti-inflammatory effect);
- activation of the synthesis of own IFN, which reduces the recovery time.
Especially bright antiviral action is typical for recombinant interferons alpha 2b, 2a and beta. They block the production of viral proteins and prevent the reproduction of pathogens. One of the important advantages of drugs based on them is minimal toxicity and the possibility of prescribing in childhood.
Synthesis
Obtaining recombinant interferons occurs in stages:
- isolation of messenger RNA after activation of interferon production in bacterial culture;
- synthesis of complementary DNA based on RNA;
- embedding the DNA obtained at the previous stage into plasmid vectors - extrachromosomal DNA molecules capable of independent copying inside bacterial cells and responsible for the production of proteins;
- obtaining recombinant DNA;
- synthesis of clones of microorganisms that produce interferon;
- reproduction of bacterialcultures on a nutrient medium;
- isolation of bacterial cells by centrifugation;
- precipitation of interferon proteins from solution;
- purification of recombinant interferon by affinity chromatography or other methods.
Propagation of clone culture takes place in industrial conditions in reactors, and the previous stages - in laboratories. Recombinant IFNs are produced outside the human body, the human interferon gene is embedded in their genetic material.
There are several bacterial cultures from which these proteins are obtained. Below is what recombinant alpha 2b interferon is made of:
- Escherichia coli (accumulation of the product occurs intracellularly);
- hay bacterium Bacillussubtilis (releasing interferons into the environment);
- Pseudomonas aeruginosa Pseudomonas aeruginosa;
- yeast fungi Saccharomycopsis fibuligera.
The last type of producers has the following advantages over others:
- possibility of using cheap culture media;
- easy separation when separating;
- high process performance (more than 10 times compared to others);
- the process of adding carbohydrate groups, similar in mechanism to that in animal cells.
Issue Forms
Recombinant interferons 2b, 2a and beta are available in the following dosage forms:
- injectable solutions;
- lyophilizates;
- drops and films foreye;
- oral solutions;
- candles and microclysters for rectal and vaginal administration;
- ointments;
- gels;
- pills;
- aerosols;
- spherical vesicles (liposomes).
Recombinant IFN alpha
Synthetic alpha-interferons are fully consistent with natural proteins. They play an important role in triggering the immune response in the human body, activate the production of important cytokines, mediate between innate and adaptive immunity, and provide immunological "memory".
The table below shows the main characteristics of some recombinant interferon preparations of this type:
| Name | Type | Issue form | Indications |
| "Reaferon-ES" | Alpha 2a | Lyophilisate for solution for injection and topical use, ampoules and vials |
Adults:
Children over 1 year old:
|
| "Viferon" | Alpha 2a | Rectal suppositories |
Adults and children:
In newborns:
|
| "Roferon-A" | Alpha 2a | Syringe tube |
Viral pathologies:
Disorders of the lymphatic system:
Tumours:
|
| "Interal-P" | Alpha 2a | Lyophilisate for solution for injection |
Adults:
Children:
|
| "Intron-A" | Alpha 2b | Solution for intravenous and s/c injections |
Viral and malignant diseases:
|
| "Laifferon" | Alpha 2b | Solution for intramuscular injection and instillation into the eye | Similar to "Interal-P" |
| "Infagel" | Alpha 2b | Gel in tubes for external use | Treatment of herpes, prevention of influenza and SARS |
| "Rialdiron" | Alpha 2b | Lyophilisate for IM and IV administration | Diseases described for Intron-A, as well as tick-borne encephalitis, mycosis fungoides and Cesari syndrome |
| "Berofor" | Alpha 2c | Eye drops in capillary pipettes | Viral eye infections |
Drugs of the newgenerations are pegylated (or conjugated) alpha-IFN, which are characterized by a prolonged action. They show high efficiency in the treatment of viral hepatitis. These include Pegasys (IFN-α-2a) and Pegintron (human recombinant interferon 2b).
Recombinant beta-IFN
Among beta interferons, 2 subtypes are currently distinguished - b1a (glycosylated) and b1b (non-glycolized). In addition to antiviral and immunomodulatory effects, they affect the nervous system and are used to treat multiple sclerosis. The drugs are administered subcutaneously or intramuscularly. It has been clinically proven that the reduction in the frequency of exacerbations of the disease occurs by almost a third, but there are still no clear criteria for evaluating effectiveness.
The mechanism of action of such drugs is based on the following phenomena:
- Binding of interferons with specific receptors on the cell surface, thereby activating the production of proteins with antiviral, antitumor, anti-inflammatory effects.
- Decrease in the number of new foci of sclerotic brain lesions and atrophic changes in its tissues (confirmed by MRI data).
- Inhibition of leukocyte division and their migration to the area of inflammation by reducing the production of proteolytic enzymes.
- Increased breakdown of gamma-interferon, which plays an important role in the development of multiple sclerosis.
Recombinant gamma-IFN
In Russia, recombinant gamma interferon is most widely produced as part of the drug "Ingaron". It is used in the treatment of diseases such as:
- flu (including swine flu);
- otitis media (aerosol form of the drug);
- granulomatous disease;
- osteopetrosis (congenital familial osteosclerosis);
- chronic viral hepatitis B, C;
- AIDS;
- pulmonary tuberculosis;
- oncological pathologies;
- urogenital infections;
- genital herpes and shingles;
- HPV;
- chronic prostatitis.
The aerosol form of human recombinant gamma interferon is also used for the prevention of influenza (irrigation of the nose and nasopharynx). This substance blocks the production of polypeptides responsible for the development of fibrotic changes in the liver and lung tissue.
Side effects
When treated with alpha and gamma interferons, flu-like syndrome is most often noted as side effects. It includes features such as:
- increased body temperature;
- headaches and muscle pain;
- chill;
- weakness.
These symptoms usually appear during the first or second week of treatment. They can be eliminated by reducing the dosage.
The following side effects are less common:
- indigestion;
- deterioration of sleep;
- thrombocytopenia;
- decrease in the level of leukocytes inblood;
- thyroid hormone intoxication.
When taking beta-interferons, the following negative phenomena may also occur:
- hypertension;
- tachycardia;
- arrhythmia;
- heartache;
- heart failure;
- decrease in intelligence;
- mental disorders - depression, suicidal ideation, depersonalization, epileptic seizures.
