[In vitro activity of human recombinant interferon gamma against SARS-CoV-2 virus].

INTRODUCTION: The development of drugs against SARS-CoV-2 continues to be crucial for reducing the spread of infection and associated mortality. The aim of the work is to study the neutralization of the SARS-CoV-2 virus with interferon gamma preparations in vitro. MATERIALS AND METHODS: The activity of recombinant human interferon gamma for intramuscular and subcutaneous administration of 500,000 IU and for intranasal administration of 100,000 IU against the SARS-CoV-2 virus in vitro was studied. The methodological approach of this study is based on the phenomenon of a decrease in the number of plaques formed under the action of a potential antiviral drug. RESULTS: The antiviral activity of recombinant interferon gamma has been experimentally confirmed, both in preventive and therapeutic application schemes. The smallest number of plaques was observed with the preventive scheme of application of the tested object at concentrations of 1000 and 333 IU/ml. The semi-maximal effective concentration (EC50) with the prophylactic regimen was 24 IU/ml. DISCUSSION: The preventive scheme of application of the tested object turned out to be more effective than therapeutic one, which is probably explained by the launch of the expression of various interferon-stimulated genes that affect to a greater extent the steps of virus entry into the cell and its reproduction. CONCLUSION: Further study of the effect of drugs based on recombinant interferon gamma on the reproduction of the SARS-CoV-2 virus for clinical use for prevention and treatment is highly relevant.

Luminescent polyelectrolytes with antiviral activity.

Radical polymerization was used to synthesize and characterize (co)polymers with sodium styrenesulfonate (NaSS), 4-methacryloylamidosalicylic acid (MASA), and N-vinylpyrrolidone, which have a low cytotoxicity and a high antiviral activity against the human respiratory syncytial virus. The interaction of copolymers with Tb3+ ions was studied. The complexes formed in dilute aqueous solutions at a concentration of MASA units c ⩽ 1 · 10-4 mol L-1 demonstrate a strong luminescence. The luminescence intensity is independent of copolymer composition, but increases when the NaSS units are substituted with uncharged N-vinylpyrrolidone units. The obtained Tb3+ polymer complexes are promising luminescent sensors for the visualization of biological objects interacting with copolymers.

5-(Perylen-3-ylethynyl)uracil Derivatives Inhibit Reproduction of Respiratory Viruses.

In this work, we describe the synthesis of 5-(perylen-3-ylethynyl)uridine and its ability to effectively inhibit the replication of respiratory disease pathogens in cell culture, namely: influenza A virus (IVA); type 3 parainfluenza virus (PIV-3); and human respiratory syncytial virus (RSV). Related known compounds were also analyzed: 5-(perylen-3-ylethynyl)-2'-deoxy-uridine; 5-(perylen-3-ylethynyl)-arabino-uridine; and 1-carboxymethyl-3-pivaloyloxymethyl-5-(perylen-3-ylethynyl)uracil.

[In vitro Antiviral Activity of Recombinant Antibodies of IgG and IgA Isotypes to Hemagglutinin of the Influenza A Virus].

Seasonal and highly infectious strains of the influenza A and influenza B viruses cause millions of cases of severe complications in elderly people, children, and patients with immune diseases each year. Immunoglobulin A (IgA), which is an active component of humoral immunity, can prevent the spread of the virus in the upper respiratory tract. The preparation and study of the properties of recombinant virus-specific IgA could be an important approach to finding new means of preventing and treating influenza. Based on CHO DG44 cells, we developed stable monoclonal cell lines that produce monomeric and dimeric antibodies FI6-IgA1 and FI6-IgA2m1 to hemagglutinin (HA) of the influenza A virus. When studying the productivity, growth, and stability of the obtained clones, we found that the dimeric form of antibodies of IgA1 isotype is superior to other forms. The dimeric form of IgA antibodies plays a key role in mucosal immunity. Recognizing the prospects of using dimeric IgA as prophylactic and therapeutic mucosal drugs for viral infections, we studied their virus-neutralizing and antiviral activities on MDCK cell culture and compared them with the antibodies of the IgG1 isotype. This study presents the data on antiviral and virus-neutralizing activities of the FI6-IgA1 dimers to seasonal and highly infectious strains of influenza A virus.

Synthesis and in vitro study of novel borneol derivatives as potent inhibitors of the influenza A virus.

Herein, we present the design and synthesis of a series of novel heterocyclic derivatives of (-)-borneol and (-)-isoborneol as potent inhibitors of the influenza A virus. All compounds were tested for their toxicity against MDCK cells and for virus-inhibiting activity against the influenza virus A/Puerto Rico/8/34 (H1N1). Compounds 7, 16 and 26 containing a morpholine fragment exhibited the highest efficiency as agents inhibiting the replication of the influenza virus A(H1N1) with selectivity indices of 82, 45 and 65, correspondingly. Derivatives 9 (SI = 23) and 18 (SI = 25) containing a 1-methylpiperazine motif showed moderate antiviral activity. Structure-activity analysis of this new series of borneol derivatives revealed that a 1,7,7-trimethylbicyclo[2.2.1]heptan scaffold is required for the antiviral activity.

Broad range of inhibiting action of novel camphor-based compound with anti-hemagglutinin activity against influenza viruses in vitro and in vivo.

Influenza virus continues to remain one of the leading human respiratory pathogens causing significant morbidity and mortality around the globe. Due to short-term life cycle and high rate of mutations influenza virus is able to rapidly develop resistance to clinically available antivirals. This makes necessary the search and development of new drugs with different targets and mechanisms of activity. Here we report anti-influenza activity of camphor derivative 1,7,7-trimethylbicyclo[2.2.1]heptan-2-ylidene-aminoethanol (camphecene). In in vitro experiments it inhibited influenza viruses A(H1, H1pdm09, H3 and H5 subtypes) and B with EC50's lying in micromolar range. Due to low cytotoxicity it resulted in high selectivity indices (74-661 depending on the virus). This effect did not depend on susceptibility or resistance of the viruses to adamantane derivatives amantadine and rimantadine. The compound appeared the most effective when added at the early stages of viral life cycle (0-2h p.i.). In direct hemagglutinin inhibition tests camphecene was shown to decrease the activity of HA's of influenza viruses A and B. The activity of camphecene was further confirmed in experiments with influenza virus-infected mice, in which, being used orally by therapeutic schedule (once a day, days 1-5 p.i.) it decreased specific mortality of animals infected with both influenza A and B viruses (highest indices of protection 66.7% and 88.9%, respectively). Taken together, these results are encouraging for further development of camphecene-based drug(s) and for exploration of camphor derivatives as highly prospective group of potential antivirals.

[Postmortem diagnosis of influenza during its epidemic and interepidemic periods].

OBJECTIVE: to assess the potential role of influenza virus in fatal pneumonia during the epidemic and interepidemic periods. MATERIAL AND METHODS An immunohistochemical method was used to clinically and morphologically analyze 40 fatal outcomes of acute pneumonias in 2009-2013. Laboratory tests could not establish the diagnosis of influenza in 20 cases of the study group with clinical and/or morphological pattern of this illness. Seventeen cases occurred during the epidemic period (autopsies from November 2009 to January 2010) and the seasonal rise of morbidity; 3 cases were observed during the interepidemic period. A control group was additionally formed from 20 cases with neither clinical nor further morphological evidence of suspected influenza in the presence of pneumonia in both the epidemic and interepidemic periods. RESULTS: In the study group, influenza virus nucleoprotein was detected by immunohistochemistry (IHC) in the bronchial epithelial cells with the signs of cytopathic changes in half of the cases and that in the alveolocytes in 30%. Sporadic cases displayed a positive IHC response of blood vessel endothelial cells, which was attended by staining of the epithelium and macrophages. The maximum disease periods with the virus nucleoprotein being detected by IHC in the macrophages doubled those in the epithelial cells (40 versus 22 days). The control group showed a large number of cases with a positive macrophage response that was approximately similar to that in the study group. Despite the frequent detection and intensive staining of macrophages, they demonstrated no cytopathic changes, which can be explained by the low virulence persistence of influenza virus in the macrophages. CONCLUSION: These investigations showed the role of influenza virus in the occurrence of additional deaths in the epidemic period and a possible fatal outcome in the interepidemic period.

Synthesis and antiviral activity of PB1 component of the influenza A RNA polymerase peptide fragments.

This study is devoted to the antiviral activity of peptide fragments from the PB1 protein - a component of the influenza A RNA polymerase. The antiviral activity of the peptides synthesized was studied in MDCK cell cultures against the pandemic influenza strain A/California/07/2009 (H1N1) pdm09. We found that peptide fragments 6-13, 6-14, 26-30, 395-400, and 531-540 of the PB1 protein were capable of suppressing viral replication in cell culture. Terminal modifications i.e. N-acetylation and C-amidation increased the antiviral properties of the peptides significantly. Peptide PB1 (6-14) with both termini modified showed maximum antiviral activity, its inhibitory activity manifesting itself during the early stages of viral replication. It was also shown that the fluorescent-labeled analog of this peptide was able to penetrate into the cell. The broad range of virus-inhibiting activity of PB1 (6-14) peptide was confirmed using a panel of influenza A viruses of H1, H3 and H5 subtypes including those resistant to oseltamivir, the leading drug in anti-influenza therapy. Thus, short peptide fragments of the PB1 protein could serve as leads for future development of influenza prevention and/or treatment agents.

Derivatives of usnic acid inhibit broad range of influenza viruses and protect mice from lethal influenza infection.

BACKGROUND: Influenza is a disease of significant morbidity and mortality, the number of anti-influenza drugs is small; many of them stimulate the appearance of resistant strains. In this work, we demonstrate activity of some usnic acid (UA) derivatives against influenza virus in vitro and in vivo. METHODS: Organic synthesis was used to prepare compounds. Antiviral activity of the compounds in vitro was evaluated by their ability to decrease the virus titer on Madin-Darby Canine Kidney cells. In vivo activity was evaluated by decrease of mortality and index of protection. RESULTS: Compounds were tested against a broad spectrum of influenza virus strains and showed activity against all used strains. One compound, [5] (valine enamine of UA), also significantly reduced lethality of infected animals and does not give rise to the appearance of resistant strains. Additional studies showed that hepatotoxicity of compound [5] is reduced comparatively to UA. CONCLUSION: Our results suggest that valine enamine of UA could be a potential candidate for the development of a new anti-influenza therapy.

Photodynamic inactivation of enveloped virus in protein plasma preparations by solid-phase fullerene-based photosensitizer.

BACKGROUND: The problem of transfusion-transmitted infections still remains serious and actual for health care despite the detailed testing of donors. Human immunodeficiency virus, hepatitis B and C viruses and human cytomegalovirus are among the most dangerous pathogens that can be transmitted with blood. Previously, a composition consisting of fullerene layer applied on silica gel particles was shown to inactivate influenza virus up to complete loss of infectivity. METHODS: In the present study the unit has been developed with source of irradiation whose spectrum is appropriate for solid-phase fullerene. The ability of the unit to inactivate the enveloped influenza virus in protein fraction of donor blood has been studied. RESULTS: It was shown that at optimized conditions complete inactivation of enveloped virus of extremely high initial titer (7.0-9.5 log 10 EID 50/0.2 mL) in the solution of albumin was achieved after as short time as 30 min of irradiation. This process did not affect the oxidative metabolism of neutrophils and membranes of erythrocytes evaluated by NBT reduction test and morphological analysis of erythrocytes, respectively. CONCLUSION: The data obtained suggests that the method described can be recommended for further development and optimization of the procedure of inactivation of viruses in the preparations of the plasma of donor blood.

[Anti-viral activity of a complex of the glycyrrhizic acid-alpha-glutamyltryptophan against the experimental lethal influenza infection in white mice caused by the oseltamivir-resistant strain of the virus].

Influenza virus is a leading causing factor of infectious respiratory human pathology. The search and development of novel anti-influenza drugs with a wide spectrum of activity is an important goal for medical science. In addition to specific anti-viral activity of the compound, its way of application is of great importance. In this work, we present the results of the study of the activity of a combination of glutamyl-tryptophan with glycirrhyzic acid (GTGA) against oseltamivir-resistant strain of the virus A/Vladivostok/2/09 (H1N1) at per os application on the model of the lethal influenza infection in white mice. The application of the GTGA was shown to decrease the specific mortality of animals (index of protection 43-50%), to increase the mean day of death to 2.5-3.9 days, and to reduce the infectious titer of the virus in the lung tissue to 1.5-1.9 Ig EID50/20 mg. The corresponding values for the reference compound oseltamivir were 14-25%, 1.1-1.9 days and 0.7 Ig EID50/20 mg, respectively, depending on the dose of the virus. The use of the GTGA also led to a reliable increase of the titers of interferon in the blood from 44.3 to 66.3 ME/mL. Morphological analysis revealed that GTGA lead to normalization of the structure of the lung tissue restricting the level of the cytodestruction and inflammation. The results obtained in this work allow the combination studied to be suggested as a promising anti-influenza drug that is active against the drug-resistant virus strains and can be applied orally.

[The anti-viral activity of the complex glycyrrhizic acid-alpha-glutamyl-tryptophan against experimental lethal influenza infection in white mice caused by oseltamivir-resistant strain of the virus].

Influenza virus is a leading causing factor of infectious respiratory human pathology. The ability to implement the antigenic drift and development of drug resistance makes it important to develop novel anti-influenza drugs of wide spectrum of activity. In this work, we present the results of the study of the activity of a combination of glycyrrhizic acid with dipeptide alpha-glutamyl-tryptophan against oseltamivir-reistant strain of the virus Al Vladivostok/2/09 (H1 N1) on the model of lethal influenza infection in white mice. Application of Orvilax was shown to decrease the specific mortality of animals (index of protection 39-67% depending on the dose of the virus and drugs combination), to increase the mean day of death to 3.7-5.0 days and decrease the infectious titer of the virus in lung tissue to 1.3 Ig EID50/20 mg. The corresponding figures for the reference compound Tamiflu were 8-11%, 0.5-1.5 days, and 0.6 Ig EID50/20 mg. The use of Orvilax also led to reliable increase of the titers of interferon in the blood from 30.4 to 56.5 ME/mL. The results obtained allow the drug to be considered as a promising anti-influenza remedy that is active against the drug-resistant virus strains.

[Effect of a combination of glutamyl-tryptophan and glycyrrhizic acid on the course of acute infection caused by influenza (H3H2) virus in mice].

The purpose of the study was to evaluate the modulating effect of glutamyl-tryptophan (EW), glycyrrhizic acid (GA), and their combination on the course of experimental infection caused by influenza A (H3N2) virus in mice. The animals were infected with influenza A/Aichi/2/68 (H3N2) virus in a dose of 1 or 10 LD50. GA (10 mg/kg body weight) and EW (0.1, 10, and 1000 microg/kg) alone or in combination were intraperitoneally injected for 5 days, starting on day 1 of virus infection. Rimantadine 50 mg/kg/day was used as a comparison drug. The combination of EW (1000 microg/kg) and GA (10 mg/kg) was ascertained to exert the maximum protective effect manifesting itself in reducing the death of infected animals (by 75-79% compared to the control depending on the viral dose) and the titers of viruses accumulated in the lung (5-6 log EID50) and in preventing lung tissue edema and inflammation. The noted effect was comparable with that seen in the use of rimantadine. The agents used alone had a lower efficacy than rimantadine. The findings permit the combination of GA and EW to be considered to be a promising agent for the treatment of influenza.

[Development of novel drugs against influenza virus based on synthetic and natural compounds].

Recent progress of the laboratory in the area of the search and development of novel remedies for prophylaxis and treatment of influenza is reviewed in this work. The data of the study of the anti-viral activity of compounds from the chemical groups of azolo-adamantanes, triterpenes, derivatives of benzimidazole, usnic acid, and other heterocyclic substances are presented. The protective properties of the plant antioxidants at lethal influenza infection of animals are discussed. High virus-inhibiting activity of natural polysaccharides and their complexes with silver ions is shown against influenza virus. The data presented allow listed groups of compounds to be suggested as promising candidates for further development of anti-influenza drugs.

[Protective activity of Ingavirin in experimental lethal influenza due to pandemic influenza virus A (H1N1)v in albino mice].

Despite obvious success in the vaccine development and chemotherapy of influenza, it remains a poorly controlled infection leading to emergence of new pandemic variants of the virus with high morbidity and mortality. We investigated the protective activity of Ingavirin against the lethal influenza A (H1N1) 2009 virus infection on albino mice. Oral use of Ingavirin resulted in sharp decreasing of the mortality (index of protection up to 57%), slight decreasing of the infectious titer of the virus in the lungs (up to 40-fold), normalizing of the body weight dynamics and the lung tissue structure vs. the placebo-treated control. The degree of the bronchial epithelium damage was also strongly decreased. The results allow to consider Ingavirin as an effective antiviral against the current pandemic influenza virus.

[Antiviral activity of Ingavirin in experimental lethal influenza due to influenza virus B in albino mice].

The protective activity of Ingavirin against experimental infection caused by influenza B virus was studied on albino mice vs. Arbidol. Oral use of Ingavirin was shown to decrease the infectious titers of the virus in the animal lung tissue, to normalize the body weight dynamics, to lower the mortality and to increase the average lifespan vs. the placebo-treated animals. The activity of Ingavirin was higher than that of the reference drug. The results allowed to consider Ingavirin as a prospective agent for the treatment of influenza infection in humans.