Rationale.According to the World Health Organization, seasonal influenza causes approximately 3 to 5 million cases of severe illness requiring hospitalization annually, with 290,000 to 650,000 of these cases resulting in death. Recombinant antibodies represent one of the most modern and promising classes of drugs for effective influenza therapy. Objective.To evaluate the properties, specificity, and virus-neutralizing activity of the recombinant antibody FM08, targeting the stem domain of influenza virus hemagglutinin, in the IgA1 and IgG1 formats. Methods.Expression plasmids were constructed using molecular genetic techniques. Experimental samples of FM08 antibody of IgA1 and IgG1 isotypes were produced by transient expression in HEK293 cell culture under serum-free conditions and subsequently purified. Biological activity was assessed comparatively using electrophoretic separation, ELISA, and a microneutralization assay. The study utilized influenza A virus strains of subtypes H1N1pdm, H2N2, H3N2, H5N1, as well as influenza B virus strains (from both genetic lineages). Results.The genetic constructs were shown to enable the accumulation of recombinant FM08 antibodies of IgA1 and IgG1 isotypes in eukaryotic cell cultures. Both FM08 antibody isotypes exhibited nearly identical binding patterns and, starting from a concentration of 16 ng/µl, interacted with influenza A virus strains from both phylogenetic groups, with the exception of the H1N1 1934 strain. The 50% inhibitory concentration (IC₅₀) for binding was 1.49 µg/ml. FM08 antibodies of both IgA1 and IgG1 isotypes neutralized influenza A/California/07/09 (H1N1pdm09) virus with IC₅₀ values of 1–4 µg/ml and influenza A/Cambodia/e0826360/2020 (H3N2) virus with IC₅₀ values of 20 µg/ml. Conclusion.The study of thein vitrobiological activity of the obtained experimental FM08 antibody samples of IgA1 and IgG1 isotypes demonstrated their high potential as an antiviral agent.

BACKGROUND: The innate immune response plays a crucial role in protecting the organism against viral pathogens, important part of which are pattern recognition receptors, such as Toll-like and RIG-I-like receptors. It is known that viral invasion, including influenza virus infection, leads to the activation of intracellular pattern recognition receptors such as TLR3, TLR7, TLR8, and TLR9, which are localized in the endoplasmic reticulum, endosomes, and lysosomes, as well as MDA5 and RIG-I, which are cytosolic sensors of viral RNA not associated with cell membranes. The expression of these genes, their proper functioning, and regulation are of critical importance for ensuring an adequate immune response and the establishment of antiviral protection. AIM: The aim of this study is to develop and validate a quantitative PCR system for assessing the expression of TLR3, TLR7, TLR8, TLR9, MDA5, and RIGI genes in mouse tissues and organs. METHODS: Gene expression levels were analyzed using reverse transcription polymerase chain reaction with specially developed panels of primers and fluorescent probes. For approbation were selected female inbred BALB/c albino mice aged 8–10 weeks, infected with influenza A/PR8/34 (H1N1) virus. RESULTS: In this study, a test system based on multiplex polymerase chain reaction was developed for assessing the expression of endosomal receptor genes TLR3, TLR7, TLR8, and TLR9, as well as cytosolic sensors MDA5 and RIG-I. The amplification efficiency was 99 for TLR3, 106 for TLR7, and 107% for the remaining genes. This test system was used to study the expression levels of TLRs and RLRs in the lung and spleen tissues of BALB/c mice infected with influenza A/PR8/34 (H1N1) virus. According to the obtained results, 24 hours post-infection, a significant change in mRNA levels of TLR3, TLR7, TLR8, TLR9, and MDA5 was observed in the lungs but not in the spleens of infected animals. CONCLUSION: The developed test system can be used for analyzing the expression of certain intracellular PRRs, providing opportunities for a deeper investigation of the pathophysiological mechanisms underlying the immune response.

Antibodies produced by the human immune system in response to vaccination or pathogen exposure represent an essential—and sometimes the only—means of combating viral infections. Scientific and technological advances have led to the emergence of a new class of antiviral agents in the biopharmaceutical market: therapeutic recombinant monoclonal antibodies. However, their potential is significantly limited due to low stability and aggregation of recombinant antibodies, as well as the high cost of their production and purification. Over the past decade, the technology of transient in vivo protein expression through the delivery of exogenous mRNA encoding the protein of interest into target cells has gained widespread adoption. Exogenous mRNAs encoding recombinant antibodies can provide stable, prolonged, and safe translation of both full-length antibodies and their various truncated forms. Moreover, mRNA technologies make it possible to develop new approaches to creating protective antibodies, such as intracellular or membrane-anchored antibodies targeted to specific cell types. In 2024 alone, more than one thousand scientific papers were published on the development and use of mRNA as vaccine and therapeutic agents. This review discusses current experimental mRNA-based therapeutics encoding antibodies that exhibit protective properties against viral pathogens.

Introduction. Influenza can cause diseases of varying severity, sometimes leading to hospitalization or death. One of the most promising strategies aimed at reducing morbidity and preventing the risks of severe consequences of infection is the use of broad-spectrum antibodies that provide effective protection against infection with seasonal strains. The aim of the study was to evaluate the protective activity of CR9114 antibodies of the IgG1 and IgA1 isotypes when administered systemically and locally against experimental influenza infection in mice. Materials and methods. The recombinant antibodies CR9114 of IgG1 or IgA1 isotypes were administered intranasally to BALB/c mice at a dose of 100 or 20 μg 24 hours before infection with influenza virus A/California/07/09 (H1N1)pdm09 virus at a dose of 10 MLD50 (prophylactic regimen) and/or 24 hours after infection (therapeutic regimen). Body weight dynamics were assessed and mortality was recorded in the animals for 14 days after infection. Results. Intranasal administration of IgG1 or IgA1 isotype antibodies in the therapeutic-prophylactic regimen led to a decrease in viral load in the respiratory tract tissues of infected mice. At the same time, parenteral administration of IgG (but not IgA) also reduced the virus titer in the nasal passages (but not in the lungs) of mice. It was demonstrated that prophylactic administration of IgG1 or IgA1 antibodies provides complete protection against lethal influenza infection. Conclusion. Intranasal prophylactic administration of human neutralizing antibodies CR9114 of IgG1 or IgA1 isotypes provides 100% survival of mice in lethal infection with influenza A/California/07/09 (H1N1)pdm09 virus. At the same time, Fc fragments of immunoglobulins of different isotypes, responsible for effector functions, appear to influence the degree of antiviral protection.

MxA is a cytoplasmic protein induced in human cells exposed to type I and III interferons. It can inhibit various viruses, including influenza A, by blocking the early steps of the viral replication cycle. The rapid advancement of mRNA-based technology has allowed us to evaluate the antiviral activity of MxA-mRNA, encoding intracellular MxA protein, and explore its potential as a therapeutic agent. In this study, we used in vitro transfection methods to obtain functional, mature MxA-mRNA and evaluate its activity within cells. We also observed an undesirable cellular response to transfection with exogenous mRNAs, which involved interferon III induction and reduced cell viability. Nevertheless, preventive administration of MxA-mRNA led to a specific 10–80-fold decrease in influenza A and B levels in cell supernatants—an effect not observed with the control GFP-Luc-mRNA. Additionally, we investigated the antiviral activity of MxA-mRNA against RNA viruses, such as SARS-CoV-2 and both serotypes of RSV, but we could not demonstrate a significant virus-specific effect of exogenous mRNA on their replication. We believe that mRNAs that encode native antiviral proteins have great therapeutic potential.

Induciruemyj interferonami tipa I i tipa III chelovecheskij belok MxA yavlyaetsya vazhnym mediatorom vrozhdennogo immuniteta i proyavlyaet antivirusnuyu aktivnost' v otnoshenii shirokogo spektra RNK- i DNK-soderzhashchih virusov. Po poslednim dannym, sverhekspressiya belka MxA povyshaet chuvstvitel'nost' k provodimoj himioterapii i yavlyaetsya odnim iz faktorov blagopriyatnogo prognoza dlya pacientov s rakom molochnoj zhelezy. Ekzogennaya mRNK, sposobnaya k vnutrikletochnoj produkcii belka MxA, ne tol'ko obladaet potencialom dlya lecheniya respiratornyh virusnyh infekcij, no i mozhet stat' vazhnym instrumentom dlya fundamental'nyh issledovanij. Cel'yu raboty bylo skonstruirovat' i poluchit' metodom in vitro transkripcii (IVT) ekzogennuyu mRNK, kodiruyushchuyu funkcional'nyj citoplazmaticheskij belok MxA cheloveka; izuchit' ee translyacionnye svojstva; ocenit' i vyyavit' zakonomernosti v ekspressii nekotoryh genov sistemy interferonov v otvet na vvedenie etoj ekzogennoj mRNK v kletki. V rezul'tate raboty byli uspeshno skonstruirovany i polucheny metodom IVT ekzogennye mRNK (v kolichestvah do 200 mkg), sposobnye k effektivnoj translyacii (do 20 ng/ml belka so 100 ng mRNK v lunke 96-lunochnogo plansheta) v eukarioticheskih kletochnyh sistemah; podtverzhdeno diffuznoe vnutrikletochnoe raspredelenie belka MxA v kletkah MDCK; vyyavleny dostovernye izmeneniya ekspressii interferon-stimuliruemyh genov, takih kak OAS1, PKR (EIF2AK2), MDA5, RIG-I. Nashi dal'nejshie issledovaniya budut posvyashcheny ocenke terapevticheskogo potenciala razrabotannyh ekzogennyh mRNK v otnoshenii virusov grippa A i V, respiratorno-sincitial'nogo virusa i koronavirusa SARS-CoV-2.

Introduction. Respiratory syncytial virus (RSV) is the most common pathogen causing lower respiratory tract infections in children. RSV also poses a serious threat to the elderly and immunocompromised patients. Developing a therapy based on recombinant human antibodies to block the RSV fusion (F) glycoprotein is urgent to reduce the incidence of RSV infections and prevent associated complications. Aim. To design plasmid vectors for efficient production of the recombinant monoclonal antibody FM1 in a eukaryotic expression system targeting the RSV fusion (F) glycoprotein and to evaluate its activity against RSV subtypes A and B in vitro. Materials and methods. Constructs encoding the recombinant antibody FM1 were designed using genetic engineering. Recombinant antibodies were produced in the CHO-K1 cell line through transient expression. Antibody specimens were purified from the culture supernatant using affinity chromatography, with a modified protein A as the ligand. The virus-neutralizing activity of the antibody was evaluated in a microneutralization assay using several RSV strains on a Vero cell monolayer culture. Results. We developed a two-plasmid vector system to produce the recombinant FM1 antibody targeting the RSV F glycoprotein, using CHO cells as transient producers. The antibody was successfully produced, purified, and characterized, with its biological activity confirmed. The FM1 antibody demonstrated enhanced virus-neutralizing activity against reference and seasonal RSV strains of subtypes A and B compared to the control drug palivizumab. Conclusion. A recombinant FM1 antibody-based drug could address the import substitution challenge for protective measures against RSV infection. The authors are currently developing a stable FM1 producer clone with high productivity and viability and investigating the therapeutic efficacy of this antibody in a sublethal RSV infection mouse model.

The design of cationic liposomes for efficient mRNA delivery can significantly improve mRNA-based therapies. Lipoplexes based on polycationic lipid 1,26-bis(cholest-5-en-3β-yloxycarbonylamino)-7,11,16,20-tetraazahexacosane tetrahydrochloride (2X3) and helper lipid 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) were formulated in different molar ratios (1:1, 1:2, 1:3) to efficiently deliver model mRNAs to BHK-21 and A549. The objective of this study was to examine the effect of 2X3-DOPE composition as well as lipid-to-mRNA ratio (amino-to-phosphate group ratio, N/P) on mRNA transfection. We found that lipoplex-mediated transfection efficiency depends on both liposome composition and the N/P ratio. Lipoplexes with an N/P ratio of 10/1 showed nanometric hydrodynamic size, positive ζ potential, maximum loading, and transfection efficiency. Liposomes 2X3-DOPE (1:3) provided the superior delivery of both mRNA coding firefly luciferase and mRNA-eGFP into BHK-21 cells and A549 cells, compared with commercial Lipofectamine MessengerMax.

BACKGROUND: The innate immune response, particularly the interferon system, plays a crucial role in defending the host against viral pathogens. Interferon signaling induces the expression of specific antiviral proteins known as interferon-stimulated genes, which inhibit viral replication through various mechanisms. AIM: This study aimed to develop a quantitative PCR system to assess the molecular regulation of human interferon-stimulated genes MxA, OAS1, and PKR, and to determine their expression in blood leukocytes in response to RNA-containing viruses. MATERIALS AND METHODS: Leukocytes were isolated from patients with laboratory-confirmed influenza and COVID-19 infections 3–4 days after symptom onset. Ex vivo viral infection was induced using influenza viruses A/California/07/09pdm (H1N1pdm09), B/Malaysia/2506/04 (Vic), strain A2 respiratory syncytial virus, and SARS-CoV-2 HCoV-19/Russia/SPE-RII-3524V/2020. RESULTS: A multiplex qPCR assay was developed for analyzing human MxA, OAS1, and PKR gene expression, with high amplification efficiency. The test system was used to study the molecular regulation of these genes in leukocytes in influenza and COVID-19 patients. The expression levels of MxA, OAS1, and PKR genes were significantly increased in blood leukocytes of hospitalized patients 3–4 days after symptom onset. Stimulation of leukocytes by influenza A, influenza B, and respiratory syncytial virus led to increased mRNA levels of these genes, while stimulation by SARS-CoV-2 did not result in changes in gene expression. CONCLUSIONS: The multiplex test system can be used to characterize the expression of antiviral effector interferon-stimulated genes, aiding in the study of virus evasion from the innate immune response.

Influenza poses a significant public health concern, and the development of therapeutic antibodies provides a promising avenue for its treatment. In this study, we generated mRNA sequences encoding neutralizing antibodies targeting the hemagglutinin of influenza A virus, as well as antibodies specific to the nucleoprotein of influenza B virus. We successfully demonstrated the antiviral activity of mRNA-encoded antibodies targeting the hemagglutinin against influenza A virus in vitro.

The major protective immune response against viruses is production of type I and III interferons (IFNs). IFNs induce the expression of hundreds of IFN-stimulated genes (ISGs) that block viral replication and further viral spread. The ability of respiratory viruses to suppress induction of IFN-mediated antiviral defenses in infected epithelial cells may be a factor contributing to the particular pathogenicity of several strains. In this report, we analyzed expression of IFNs and some ISGs in an alveolar epithelial cell subtype (A549) in response to infection with: influenza A viruses (A/California/07/09pdm (H1N1), A/Texas/50/12 (H3N2)); influenza B virus (B/Phuket/3073/13); adenovirus type 5 and 6; or respiratory syncytial virus (strain A2). IFNL and ISGs expression significantly increased in response to infection with all RNA viruses 24 hpi. Nevertheless, only IBV led to early increase in IFNL and ISGs mRNA level. IBV and H1N1 infection led to elevated proinflammatory cytokine production. We speculate that augmented IFN-α, IFN-β, IL-6 levels negatively correlate to SOCS1 expression. Importantly, we showed a decrease in IFNLR1 mRNA in case of IBV infection that implies the existence of negative ISGs expression regulation at IFNλR level. It could be either a specific feature of IBV or a consequence of early IFNL expression.

Introduction: Respiratory infections, collectively, are one of the World's most common and serious illness groups. As recent observations have shown, the most severe courses of acute respiratory infection, often leading to death, are due to uncontrolled cytokine production (hypercytokinemia). Methods: The study involved 364 patients with respiratory illness being treated in clinics in St. Petersburg (Russia) in 2018–2019 and 30 healthy controls. Cytokine analysis was carried out in the acute phase of illness (2–3 days from onset of initial symptoms) and in the stage of recovery (days 9–10). The research presented is devoted to the assessment of mRNA expression of specific cytokines (interleukin [IL]-1b, IL-2, IL-4, IL-6, IL-8, IL-10, IL-18, tumor necrosis factor-α [TNF-α], and interferon-λ) and MxA in whole blood leukocytes, by means of real-time polymerase chain reaction. Results: In 70% of patients, bacterial or viral pathogens were identified, with influenza viral infections (types A and B) prevailing. Significant increases in the expression of IL-18, TNF, and IL-10 were observed, relative to controls, only with influenza viral infections. We have shown a difference in IL-6 mRNA expression in patients with bacterial or viral pathogens. No statistically significant difference was found in white blood cells IL-4 expression levels between patients and healthy controls. Conclusion: Investigation of the nuances of systemic cytokine production, in response to specific viral and bacterial pathogens, makes it possible to assess the risks of developing hypercytokinemia during respiratory infection with agents circulating in the human population and to predict the pathogenicity and virulence of circulating threats.

In this study, we developed a novel, multiplex qPCR assay for simultaneous detection of RIG-1, MDA5, and IFIT-1 at the mRNA level. The assay was validated in A549 cells transfected with in vitro transcribed RNAs. Both exogenous RNA-GFP and self-amplifying (saRNA-GFP) induced significant expression of RIG-1, MDA5, IFIT-1, as well as type I and III interferons. In contrast, native RNA from intact A549 cells did not upregulate expression of these genes. Next, we evaluated RIG-1, MDA5, and IFIT-1 mRNA levels in the white blood cells of patients with influenza A virus (H3N2) or SARS-CoV-2. In acute phase (about 4 days after disease onset) both viruses induced these genes expression. Clinical observations of SARS-CoV-2 typically describe a two-step disease progression, starting with a mild-to-moderate presentation followed by a secondary respiratory worsening 9 to 12 days after the first onset of symptoms. It revealed that the expression of RIG-1, MDA5, and MxA was not increased after 2 and 3 weeks from the onset the disease, while for IFIT-1 it was observed the second peak at 21 day post infection. It is well known that RIG-1, MDA5, and IFIT-1 expression is induced by the action of interferons. Due to the ability of SOCS-1 to inhibit interferon-dependent signaling, and the distinct antagonism of SARS-CoV-2 in relation to interferon-stimulated genes expression, we assessed SOCS-1 mRNA levels in white blood cells. SARS-CoV-2 patients had increased SOCS-1 expression, while the influenza-infected group did not differ from heathy donors. Moreover, SOCS-1 mRNA expression remained stably elevated during the course of the disease. It can be assumed that augmented SOCS-1 expression is one of multiple mechanisms that allow SARS-CoV-2 to escape from the interferon-mediated immune response. Our results implicate SOCS-1 involvement in the pathogenesis of SARS-CoV-2.

Abstract Objective: Despite the fact that exogenous mRNA has great prospects for the development of therapeutic medicine, its use is still limited. As the immediate protein precursor, positive-stranded mRNA may represent a suitable alternative to prevent of viral infections. Results: Here, we focused our efforts on making the exogenous RNA encoding human interferon lambda (hIFN-λ1). Using the in vitro transcription method, we obtained hIFN-λ1 RNA and showed that it is capable to rapid translation in transfected cells. We compared the translation efficiency of mRNAs containing unmodified and modified (pseudouridine and 5-methyl-cytidine) nucleosides. Our results showed that the level of hIFN-λ1 during translation from containing modified nucleosides mRNA was 10-fold or more times higher compare to unmodified mRNA. We found that the delivery of exogenous mRNA encoding GFP and hIFN-λ1 in cells resulted in an increase of MDA5, MxA, OAS-1, and IFN-αexpression, which indicate to the activation of innate immune response. At last it was shown that mRNA encoding hIFN-λ1 significantly reduced the reproduction of A/California/07/09 (H1N1pdm09) in comparison with the nonspecific mRNA encoding GFP.

Background: Exosomes are involved in intercellular communication and can transfer regulatory molecules between cells. Consequently, they can participate in host immune response regulation. For the influenza A virus (IAV), there is very limited information on changes in exosome composition during cell infection shedding light on the potential role of these extracellular membrane vesicles. Thus, the aim of our work was to study changes in exosomal composition following IAV infection of cells, as well as to evaluate their effect on uninfected cells. Methods: To characterize changes in the composition of cellular miRNAs and mRNAs of exosomes during IAV infection of A549 cells, NGS was used, as well as PCR to identify viral genes. Naïve A549 cells were stimulated with infected-cell-secreted exosomes for studying their activity. Changes in the expression of genes associated with the cell's immune response were shown using PCR. The effect of exosomes on IAV replication was shown in MDCK cells using In-Cell ELISA and PCR of the supernatants. Results: A change in the miRNA composition (miR-21-3p, miR-26a-5p, miR-23a-5p, miR-548c-5p) and mRNA composition (RPL13A, MKNK2, TRIB3) of exosomes under the influence of the IAV was shown. Many RNAs were involved in the regulation of the immune response of the cell, mainly by suppressing it. After exosome stimulation of naïve cells, a significant decrease in the expression of genes involved in the immune response was shown (RIG1, IFIT1, MDA5, COX2, NFκB, AnxA1, PKR, IL6, IL18). When infecting MDCK cells, a significant decrease in nucleoprotein levels was observed in the presence of exosomes secreted by mock-infected cells. Viral levels in supernatants also decreased. Conclusions: Exosomes secreted by IAV-infected cells could reduce the immune response of neighboring intact cells, leading to more effective IAV replication. This may be associated both with regulatory functions of cellular miRNAs and mRNAs carried by exosomes, or with the presence of viral mRNAs encoding proteins with an immunosuppressive function.

Type III interferons (lambda IFNs) are a quite new, small family of three closely related cytokines with interferon-like activity. Attention to IFN-λ is mainly focused on direct antiviral activity in which, as with IFN-α, viral genome replication is inhibited without the participation of immune system cells. The heterodimeric receptor for lambda interferons is exposed mainly on epithelial cells, which limits its possible action on other cells, thus reducing the likelihood of developing undesirable side effects compared to type I IFN. In this study, we examined the antiviral potential of exogenous human IFN-λ1 in cellular models of viral infection. To study the protective effects of IFN-λ1, three administration schemes were used: 'preventive' (pretreatment); 'preventive/therapeutic' (pre/post); and 'therapeutic' (post). Three IFN-λ1 concentrations (from 10 to 500 ng/mL) were used. We have shown that human IFN-λ1 restricts SARS-CoV-2 replication in Vero cells with all three treatment schemes. In addition, we have shown a decrease in the viral loads of CHIKV and IVA with the 'preventive' and 'preventive/therapeutic' regimes. No significant antiviral effect of IFN-λ1 against AdV was detected. Our study highlights the potential for using IFN-λ as a broad-spectrum therapeutic agent against respiratory RNA viruses.

The increased complexity due to the emergence and rapid spread of new viral infections prompts researchers to search for potential antiviral and protective agents for mucous membranes among various natural objects, for example, plant raw materials, their individual components, as well as the products of their chemical modification. Due to their structure, resin acids are valuable raw materials of natural origin to synthesize various bioactive substances. Therefore, the purpose of this study was to confirm the possibility of using resin acid derivatives for the drug design. As a result, we studied the cytotoxicity and biological activity of resin acid derivatives. It was shown that a slight decrease in the viral load in the supernatants was observed upon stimulation of cells (II) compared with the control. When using PASS-online modeling (Prediction of Activity Spectra for Substances), the prediction of the biological activity spectrum showed that compound (I) is capable of exhibiting antiviral activity against the influenza virus. The use of the SWISS-ADME webserver to reveal the drug-like properties of compounds did not directly indicate the presence of antiviral activity. These results indicate the potential of resin acid derivatives as a starting point for extensive research in the study of biological activity.

Type III interferons exhibit antiviral activity against influenza viruses, coronaviruses, rotaviruses, and others. In addition, this type of interferon theoretically has therapeutic advantages, in comparison with type I interferons, due to its ability to activate a narrower group of genes in a relatively small group of target cells. Hence, it can elicit more targeted antiviral or immunomodulatory responses. Obtaining biologically-active interferon lambda (hIFN-λ1) is fraught with difficulties at the stage of expression in soluble form or, in the case of expression in the form of inclusion bodies, at the stage of refolding. In this work, hIFN-λ1 was expressed in the form of inclusion bodies, and a simple, effective refolding method was developed. Efficient and scalable methods for chromatographic purification of recombinant hIFN-λ1 were also developed. High-yield, high-purity product was obtained through optimization of several processes including: recombinant protein expression; metal affinity chromatography; cation exchange chromatography; and an intermediate protein refolding stage. The obtained protein was shown to feature expected specific biological activity in line with published effects: induction of MxA gene expression in A549 cells and antiviral activity against influenza A virus.

A technology for creating a Russian-made instrument platform for clinical laboratory diagnosis using biochips is described. The device is a fluorescence analyzer for recording images of fluorescent biochips at excitation wave-lengths of 520 and 633 nm and determination of the fluorescence intensities in the resulting images.

ABSTRACT Type III interferons exhibit antiviral activity against influenza viruses, coronaviruses, rotaviruses, and others. In addition, this type of interferon theoretically has therapeutic advantages, in comparison with type I interferons, due to its ability to activate a narrower group of genes in a relatively small group of target cells. Hence, it can elicit more targeted antiviral or immunomodulatory responses. Obtaining biologically-active interferon lambda (hIFN-λ 1 ) is fraught with difficulties at the stage of expression in soluble form or, in the case of expression in the form of inclusion bodies, at the stage of refolding. In this work, hIFN-λ 1 was expressed in the form of inclusion bodies, and a simple, effective refolding method was developed. Efficient and scalable methods for chromatographic purification of recombinant hIFN-λ 1 were also developed. High-yield, high-purity product was obtained through optimization of several processes including: recombinant protein expression; metal affinity chromatography; cation exchange chromatography; and an intermediate protein refolding stage. The obtained protein was shown to have expected, specific biological activity in line with published effects: induction of MxA gene expression in A549 cells.