Antiviral Activity Of Drugs Research Articles

Use of Rift Valley Fever Virus Expressing NanoLuc Luciferase for the Assessment of Neutralizing Antibodies and Antivirals.

Rift Valley fever (RVF) is an arboviral zoonotic disease affecting many African countries with the potential to spread to other geographical areas. In this chapter we describe the use of a replication-competent recombinant (r)RVFV expressing NanoLuc Luciferase (Nluc) for in vitro studies. The determination of parameters such as neutralizing antibodies in serum samples, or the antiviral activity of drugs is usually carried out using standard assays based on the assessment of cytopathic effect on cell cultures. The use of a virus encoding a traceable reporter protein allows to correlate the presence or absence of infection with the detection of the product in the infected cultures, thus tracking the level of RVFV infection in an objective, quantitative manner. In addition to this quantitative measurement of results, our protocol offers two other advantages, such as a shorter time to read, given that 48h post-infection the production of the reporter protein is enough to give an accurate result, and the use of an attenuated virus, which reduces the risk of exposure.

Evaluation of the Antiviral Activity of Drugs from the Group of Polymer Electrolyte Derivatives against a Wide Range of Viruses

Background. The modern healthcare system is constantly improving and introducing new measures to protect the population from viral diseases, but the experience of the COVID-19 pandemic has shown that infections cannot always be controlled on global scale. In this regard, the development of new broad-spectrum antiviral drugs is more relevant than ever.The aim of the study was to investigate the antiviral activity and cytotoxicity of copolymers of sodium styrene sulfonate and vinyl monomers of various chemical structures, as well as to identify promising polymers for the development of new antiviral agents.Materials and methods. 14 copolymers of sodium styrene sulfonate (NaSS) with various functional comonomers were synthesized. Three viruses with different reproduction strategies and transmission methods — respiratory syncytial virus, influenza virus, and herpes virus — were selected for the assessment of antiviral activity.Results. The screening identified copolymers that showed high activity against all three viruses. It was found that the introduction of various functional groups into the structure of NaSS did not decrease antiviral activity, but significantly reduced cytotoxicity. The molecular weight has also shown a noticeable effect on the activity. Different sensitivity of viruses and cells to the studied polymers was revealed, likely due to the structural features of the virus shell and cell wall.Conclusions. The results demonstrate the potential of sodium styrene sulfonate copolymers as a model for developing a broad-spectrum antiviral drug.

Study of the Activity of Antiviral Drugs Against the Causative Agent of Chikungunya Fever in Cell Culture

Сhikungunya virus (CHIKV) is a member of the Flavivirus genus, Flaviviridae family. It belongs to the zoonotic arbovirus infections transmitted by mosquitoes of the genus Aedes. In humans, this flavivirus causes a disease known as Сhikungunya fever, etymologically related to yellow fever, dengue, West Nile, and Zika. There is no specific treatment for Сhikungunya fever, as there is no vaccine or preventive measures to date. A comparative analysis of the effectiveness of chemotherapy drugs, interferon inducers and two classes of interferon α-, β-, and γ-showed that interferon drugs effectively inhibit the reproduction of CHIKV in the Vero cell culture in a wide range of concentrations. Chemotherapy drugs Triazavirin® and Ingavirin® did not affect the reproduction of CHIKV strain FN198/66 in Vero cell culture. Ribavirin® at a concentration of 100 µg/ml almost completely suppressed the reproduction of the CHIKV virus when the drug was introduced into the culture medium both before and after infection.

Comparison of the Antiviral Activity of Remdesivir, Chloroquine, and Interferon-β as Single or Dual Agents Against the Human Beta-Coronavirus OC43.

The human beta-coronavirus strain, OC43, provides a useful model for testing the antiviral activity of various agents. We compared the activity of several antiviral drugs against OC43, including remdesivir, chloroquine, interferon (IFN)-β, IFN-λ1, and IFN-λ4, in two distinct cell types: human colorectal carcinoma cell line (HCT-8 cells) and normal human bronchial epithelial (NHBE) cells. We also tested whether these agents mediate additive, synergistic, or antagonistic activity against OC43 infection when used in combination. When used as single agents, remdesivir exhibited stronger antiviral activity than chloroquine, and IFN-β exhibited stronger activity than IFN-λ1 or IFN-λ4 against OC43 in both HCT-8 and NHBE cells. Anakinra (IL-1 inhibitor) and tocilizumab (IL-6 inhibitor) did not mediate any antiviral activity. The combination of IFN-β plus chloroquine or remdesivir resulted in higher synergy scores and higher expression of IFN-stimulated genes than did IFN-β alone. In contrast, the combination of remdesivir plus chloroquine resulted in an antagonistic interaction in NHBE cells. Our findings indicate that the combined use of IFN-β plus remdesivir or chloroquine induces maximal antiviral activity against human coronavirus strain OC43 in primary human respiratory epithelial cells. Furthermore, our experimental OC43 virus infection model provides an excellent method for evaluating the biological activity of antiviral drugs.

Predicting In Vitro and In Vivo Anti-SARS-CoV-2 Activities of Antivirals by Intracellular Bioavailability and Biochemical Activity.

Cellular drug response (concentration required for obtaining 50% of a maximum cellular effect, EC50) can be predicted by the intracellular bioavailability (F ic) and biochemical activity (half-maximal inhibitory concentration, IC50) of drugs. In an ideal model, the cellular negative log of EC50 (pEC50) equals the sum of log F ic and the negative log of IC50 (pIC50). Here, we measured F ic's of remdesivir, favipiravir, and hydroxychloroquine in various cells and calculated their anti-SARS-CoV-2 EC50's. The predicted EC50's are close to the observed EC50's in vitro. When the lung concentrations of antiviral drugs are higher than the predicted EC50's in alveolar type 2 cells, the antiviral drugs inhibit virus replication in vivo, and vice versa. Overall, our results indicate that both in vitro and in vivo antiviral activities of drugs can be predicted by their intracellular bioavailability and biochemical activity without using virus. This virus-free strategy can help medicinal chemists and pharmacologists to screen antivirals during early drug discovery, especially for researchers who are not able to work in the high-level biosafety lab.

Direct antiviral drugs and blocking monoclonal antibodies as the basis of etiotropic therapy of a novel coronavirus infection

At the beginning of 2020, a pandemic of a novel coronavirus infection was declared in the world. Since the beginning of the pandemic, the search for drugs for etiotropic therapy as the basis for the treatment of the infectious process has begun. The review provides data on the application points of antiviral activity of drugs, taking into account the life cycle of the etiological agent – the SARS-CoV-2 virus. The mechanisms of drug action on RNA-dependent RNA polymerase (molnupiravir, remdesivir, favipiravir) and protease (nirmatrelvir together with ritonavir) SARS-CoV-2 are described. Among of outpatient patients at risk, the use of molnupiravir up to 5 days from the onset of the disease provided a 30% reduction in the risk of hospitalization and an 89% reduction in the risk of death. The use of a 10-day course of remdesivir in inpatient patients led to a reduction in the duration of clinical manifestations by 5 days, and the use of the drug for 3 days on an outpatient basis had a beneficial effect on a group of high-risk patients in the form of a reduction in the risk of hospitalization and death by 87%. Among outpatient patients using favipiravir, the onset of clinical improvement was noted 4 days earlier compared to the control group. The administration of nirmatrelvir in combination with ritonavir on an outpatient basis led to an 89% reduction in the risk of hospitalization or death. The molecular basis and principles of the use of blocking monoclonal antibodies as a fundamentally new group of biological drugs for etiotropic therapy are discussed. Information is provided on the effects of drugs on alpha, beta, gamma, delta and omicron variants of the virus. The profile of drug-drug interaction of drugs and basic therapy is analyzed. Early initiation of etiotropic therapy on an outpatient regime provides a more favorable course of the disease, which is characterized by a shorter duration of clinical manifestations, a reduced risk of hospitalization and the onset of death.

Computational drug repurposing against SARS-CoV-2 reveals plasma membrane cholesterol depletion as key factor of antiviral drug activity.

Comparing SARS-CoV-2 infection-induced gene expression signatures to drug treatment-induced gene expression signatures is a promising bioinformatic tool to repurpose existing drugs against SARS-CoV-2. The general hypothesis of signature-based drug repurposing is that drugs with inverse similarity to a disease signature can reverse disease phenotype and thus be effective against it. However, in the case of viral infection diseases, like SARS-CoV-2, infected cells also activate adaptive, antiviral pathways, so that the relationship between effective drug and disease signature can be more ambiguous. To address this question, we analysed gene expression data from in vitro SARS-CoV-2 infected cell lines, and gene expression signatures of drugs showing anti-SARS-CoV-2 activity. Our extensive functional genomic analysis showed that both infection and treatment with in vitro effective drugs leads to activation of antiviral pathways like NFkB and JAK-STAT. Based on the similarity-and not inverse similarity-between drug and infection-induced gene expression signatures, we were able to predict the in vitro antiviral activity of drugs. We also identified SREBF1/2, key regulators of lipid metabolising enzymes, as the most activated transcription factors by several in vitro effective antiviral drugs. Using a fluorescently labeled cholesterol sensor, we showed that these drugs decrease the cholesterol levels of plasma-membrane. Supplementing drug-treated cells with cholesterol reversed the in vitro antiviral effect, suggesting the depleting plasma-membrane cholesterol plays a key role in virus inhibitory mechanism. Our results can help to more effectively repurpose approved drugs against SARS-CoV-2, and also highlights key mechanisms behind their antiviral effect.

Antiviral Activity of Approved Antibacterial, Antifungal, Antiprotozoal and Anthelmintic Drugs: Chances for Drug Repurposing for Antiviral Drug Discovery.

Drug repurposing process aims to identify new uses for the existing drugs to overcome traditional de novo drug discovery and development challenges. At the same time, as viral infections became a serious threat to humans and the viral organism itself has a high ability to mutate genetically, and due to serious adverse effects that result from antiviral drugs, there are crucial needs for the discovery of new antiviral drugs, and to identify new antiviral effects for the exciting approved drugs towards different types of viral infections depending on the observed antiviral activity in preclinical studies or clinical findings is one of the approaches to counter the viral infections problems. This narrative review article summarized mainly the published preclinical studies that evaluated the antiviral activity of drugs that are approved and used mainly as antibacterial, antifungal, antiprotozoal, and anthelmintic drugs, and the preclinical studies included the in silico, in vitro, and in vivo findings, additionally some clinical observations were also included while trying to relate them to the preclinical findings. Finally, the structure used for writing about the antiviral activity of the drugs was according to the families of the viruses used in the studies to form a better image for the target of antiviral activity of different drugs in the different kinds of viruses and to relate between the antiviral activity of the drugs against different strains of viruses within the same viral family.

Versatile SARS-CoV-2 Reverse-Genetics Systems for the Study of Antiviral Resistance and Replication.

The COVID-19 pandemic continues to threaten healthcare systems worldwide due to the limited access to vaccines, suboptimal treatment options, and the continuous emergence of new and more transmissible SARS-CoV-2 variants. Reverse-genetics studies of viral genes and mutations have proven highly valuable in advancing basic virus research, leading to the development of therapeutics. We developed a functional and highly versatile full-length SARS-CoV-2 infectious system by cloning the sequence of a COVID-19 associated virus isolate (DK-AHH1) into a bacterial artificial chromosome (BAC). Viruses recovered after RNA-transfection of in vitro transcripts into Vero E6 cells showed growth kinetics and remdesivir susceptibility similar to the DK-AHH1 virus isolate. Insertion of reporter genes, green fluorescent protein, and nanoluciferase into the ORF7 genomic region led to high levels of reporter activity, which facilitated high throughput treatment experiments. We found that putative coronavirus remdesivir resistance-associated substitutions F480L and V570L—and naturally found polymorphisms A97V, P323L, and N491S, all in nsp12—did not decrease SARS-CoV-2 susceptibility to remdesivir. A nanoluciferase reporter clone with deletion of spike (S), envelope (E), and membrane (M) proteins exhibited high levels of transient replication, was inhibited by remdesivir, and therefore could function as an efficient non-infectious subgenomic replicon system. The developed SARS-CoV-2 reverse-genetics systems, including recombinants to modify infectious viruses and non-infectious subgenomic replicons with autonomous genomic RNA replication, will permit high-throughput cell culture studies—providing fundamental understanding of basic biology of this coronavirus. We have proven the utility of the systems in rapidly introducing mutations in nsp12 and studying their effect on the efficacy of remdesivir, which is used worldwide for the treatment of COVID-19. Our system provides a platform to effectively test the antiviral activity of drugs and the phenotype of SARS-CoV-2 mutants.

Nanoceria Can Inhibit the Reproduction of Transmissible Gastroenteritis Virus: Consideration for Use to Prevent and Treat Coronavirus Disease

Nanoceria (cerium dioxide nanoparticles, CeO2) has a broad range of biological properties including antiviral activity. The hypothesis was that nanoceria can efficacy against coronavirus (coronavirus of porcine transmissible gastroenteritis) and potentially can target SARS-CoV-2. Transmissible gastroenteritis coronavirus (TGEV) is the etiologic agent of porcine transmissible gastroenteritis (PTG), a highly contagious pig intestinal disease. The aim of the study was to determine the antiviral activity of CeO2 nanoparticles on the model of porcine coronavirus – TGEV. Methods. We used a highly pathogenic virus strain D52-5 (BRE79), of TGEV. We evaluated antiviral activity of CeO2 nanoparticles on the experimental model of porcine coronavirus (transmissible gastroenteritis virus) in transplantable line of porcine embryonic kidney cells (PEK) culture. Results. The criterion for evaluating the inhibitory activity of antiviral drugs in different in vitro systems is the selectivity index (SI) and the reduction of infectious titer by 1.5–2.0 lgTCD50. Nanoceria effectively inhibited the reproduction of porcine coronavirus with SI index of 83.3.

SPR-Based Kinetic Analysis of the Early Stages of Infection in Cells Infected with Human Coronavirus and Treated with Hydroxychloroquine.

Cell-based assays are a valuable tool for examination of virus–host cell interactions and drug discovery processes, allowing for a more physiological setting compared to biochemical assays. Despite the fact that cell-based SPR assays are label-free and thus provide all the associated benefits, they have never been used to study viral growth kinetics and to predict drug antiviral response in cells. In this study, we prove the concept that the cell-based SPR assay can be applied in the kinetic analysis of the early stages of viral infection of cells and the antiviral drug activity in the infected cells. For this purpose, cells immobilized on the SPR slides were infected with human coronavirus HCov-229E and treated with hydroxychloroquine. The SPR response was measured at different time intervals within the early stages of infection. Methyl Thiazolyl Tetrazolium (MTT) assay was used to provide the reference data. We found that the results of the SPR and MTT assays were consistent, and SPR is a reliable tool in investigating virus–host cell interaction and the mechanism of action of viral inhibitors. SPR assay was more sensitive and accurate in the first hours of infection within the first replication cycle, whereas the MTT assay was not so effective. After the second replication cycle, noise was generated by the destruction of the cell layer and by the remnants of dead cells, and masks useful SPR signals.

Thermal and Spectroscopic Studies of Some Prepared Metal Complexes and Investigation of their Potential Anticancer and Antiviral Drug Activity against SARS-CoV-2 by Molecular Docking Simulation

A scary viral pneumonia (COVID-19) has recently engulfed the globe. The new strain of the virus, named SARS-CoV-2, belongs to the coronavirus family, so research aims to screen multimodal structure-based structure-design of ligands and drugs and then docked to the main viral protease to investigate the active binding sites. A new 3-acetyl-7-hydroxy coumarin (HL) and its Cu(II), Ni(II), Zn(II), and Mn(II) complexes have been formed and characterized by elemental analysis, IR, 1H NMR, and UV visible spectra, as well as magnetic and thermal measurements. Molar conductance experiments have shown that all complexes are non-ionic or non-electrolytes. IR spectra show that the ligand (HL) behaves as a bidentate monobasic ligand coordinating via the oxygen atom of the deprotonated phenolic -OH group and the nitrogen atom of the azo group (-N=N-), forming a six-member chelating ring. The molecular and electronic structures of the investigated compounds were also analyzed using quantum chemical calculations. The complexes’ thermal decomposition exposed the outer and inner water molecules as well as the end product, which is mainly metal oxide. The thermodynamic parameter ligand (HL) and its metal complexes are calculated using the Coats-Redfern and Horowitz Metzger methods. Using absorption spectra, the ligand (HL) binding behavior of the calf thymus DNA and its metal complexes were studied. A molecular docking simulation computational method is performed to screen the antiviral activity of drugs, natural drug activity, sources, and anti-SARS-CoV-2 genome inhibitory compounds. The primary virus protease collected from a Bank of Protein Data (PDB# 6YB7) and docked with a sequence of HL and its complexes. On the other hand, the prediction of binding between azo compound with the breast cancer receptor 3hb5-oxidoreductase and the prostate cancer mutant 2q7k – hormone was also made. The docking results were promised and indicated that the reported ligand can firmly bind to the SARS-CoV-2, breast, and prostate cancer leads to inhibition of its infectious impact. The cytotoxic activity of ligand (HL) and its metal complexes was tested against human cancer MCF-7 (breast cancer).

COMPARE Analysis, a Bioinformatic Approach to Accelerate Drug Repurposing against Covid-19 and Other Emerging Epidemics.

A novel bioinformatic approach for drug repurposing against emerging viral epidemics like Covid-19 is described. It exploits the COMPARE algorithm, a public program from the National Cancer Institute (NCI) to sort drugs according to their patterns of growth inhibitory profiles from a diverse panel of human cancer cell lines. The data repository of the NCI includes the growth inhibitory patterns of more than 55,000 molecules. When candidate drug molecules with ostensible anti-SARS-CoV-2 activities were used as seeds (e.g., hydroxychloroquine, ritonavir, and dexamethasone) in COMPARE, the analysis uncovered several molecules with fingerprints similar to the seeded drugs. Interestingly, despite the fact that the uncovered drugs were from various pharmacological classes (antiarrhythmic, nucleosides, antipsychotic, alkaloids, antibiotics, and vitamins), they were all reportedly known from published literature to exert antiviral activities via different modes, confirming that COMPARE analysis is efficient for predicting antiviral activities of drugs from various pharmacological classes. Noticeably, several of the uncovered drugs can be readily tested, like didanosine, methotrexate, vitamin A, nicotinamide, valproic acid, uridine, and flucloxacillin. Unlike pure in silico methods, this approach is biologically more relevant and able to pharmacologically correlate compounds regardless of their chemical structures. This is an untapped resource, reliable and readily exploitable for drug repurposing against current and future viral outbreaks.

Investigating the potential antiviral activity drugs against SARS-CoV-2 by molecular docking simulation

Recently, scary viral pneumonia is known as (COVID-19) has swept the whole world. The new virus strain designated as SARS-CoV-2 belonging to the coronavirus family. Although the current medical research directed towards the development of a novel therapeutic agent, no anti-viral drug approved until now. On the medical scale, the development of an approved drug is a time-consuming process, so research is directed towards screening of ligands and drugs multimodal structure-based-design and then docked to the main viral protease to investigate the active binding sites. The bioinformatic approaches used to evaluate the competence of a comprehensive range of ligands and drugs before their clinical implementation. In this study, a computational approach through molecular docking simulation is conducted for screening the antiviral activity of drugs, natural sources, and inhibitory compounds against the SARS-CoV-2 genome. The main virus protease was collected from a Protein Data Bank (PDB# 6YB7) and docked with a sequence of 19 approved antiviral drugs, 10 natural inhibitory ligands against COVID-19 downloaded from PubChem, in addition to 10 natural sources optimized for Escherichia coli BL21 (DE3) to identify the antiviral activity of these candidates against COVID-19. The docking results were promised and indicated that the reported ligands can firmly bind to the SARS-CoV-2 main protease and leads to inhibition of its infectious impact.

Prioritization of Anti-SARS-Cov-2 Drug Repurposing Opportunities Based on Plasma and Target Site Concentrations Derived from their Established Human Pharmacokinetics.

There is a rapidly expanding literature on the in vitro antiviral activity of drugs that may be repurposed for therapy or chemoprophylaxis against severe acute respiratory syndrome‐coronavirus 2 (SARS‐CoV‐2). However, this has not been accompanied by a comprehensive evaluation of the target plasma and lung concentrations of these drugs following approved dosing in humans. Accordingly, concentration 90% (EC90) values recalculated from in vitro anti‐SARS‐CoV‐2 activity data was expressed as a ratio to the achievable maximum plasma concentration (Cmax) at an approved dose in humans (Cmax/EC90 ratio). Only 14 of the 56 analyzed drugs achieved a Cmax/EC90 ratio above 1. A more in‐depth assessment demonstrated that only nitazoxanide, nelfinavir, tipranavir (ritonavir‐boosted), and sulfadoxine achieved plasma concentrations above their reported anti‐SARS‐CoV‐2 activity across their entire approved dosing interval. An unbound lung to plasma tissue partition coefficient (K p U lung) was also simulated to derive a lung Cmax/half‐maximal effective concentration (EC50) as a better indicator of potential human efficacy. Hydroxychloroquine, chloroquine, mefloquine, atazanavir (ritonavir‐boosted), tipranavir (ritonavir‐boosted), ivermectin, azithromycin, and lopinavir (ritonavir‐boosted) were all predicted to achieve lung concentrations over 10‐fold higher than their reported EC50. Nitazoxanide and sulfadoxine also exceeded their reported EC50 by 7.8‐fold and 1.5‐fold in lung, respectively. This analysis may be used to select potential candidates for further clinical testing, while deprioritizing compounds unlikely to attain target concentrations for antiviral activity. Future studies should focus on EC90 values and discuss findings in the context of achievable exposures in humans, especially within target compartments, such as the lungs, in order to maximize the potential for success of proposed human clinical trials.

Improving Encapsulation of Hydrophilic Chloroquine Diphosphate into Biodegradable Nanoparticles: A Promising Approach against Herpes Virus Simplex-1 Infection

Chloroquine diphosphate (CQ) is a hydrophilic drug with low entrapment efficiency in hydrophobic nanoparticles (NP). Herpes simplex virus type 1 (HSV-1) is an enveloped double-stranded DNA virus worldwide known as a common human pathogen. This study aims to develop chloroquine-loaded poly(lactic acid) (PLA) nanoparticles (CQ-NP) to improve the chloroquine anti- HSV-1 efficacy. CQ-NP were successfully prepared using a modified emulsification-solvent evaporation method. Physicochemical properties of the NP were monitored using dynamic light scattering, atomic force microscopy, drug loading efficiency, and drug release studies. Spherical nanoparticles were produced with modal diameter of <300 nm, zeta potential of −20 mv and encapsulation efficiency of 64.1%. In vitro assays of CQ-NP performed in Vero E6 cells, using the MTT-assay, revealed different cytotoxicity levels. Blank nanoparticles (B-NP) were biocompatible. Finally, the antiviral activity tested by the plaque reduction assay revealed greater efficacy for CQ-NP compared to CQ at concentrations equal to or lower than 20 µg mL−1 (p < 0.001). On the other hand, the B-NP had no antiviral activity. The CQ-NP has shown feasible properties and great potential to improve the antiviral activity of drugs.

Methods of Assessing Biological Activity of Recombinant Human Interleukin-7 and Stability Study of the Preparation on Its Basis

Background. Interleukin-7 is one of the most important immune regulatory cytokines. Recombinant human interleukin-7 (rIL-7) in aqueous solution is subjected to chemical degradation mechanisms such as proteolysis, oxidation, disulfide exchange, oligomerisation etc. Such changes affect the shelf life of the preparation on the basis of rIL-7. Evaluation of the biological activity of rIL-7 can be carried out by assessing its antiviral activity. Objective. Comparison of methods for inhibiting reproduction of the influenza virus, herpes simplex virus and hepatitis C virus with recombinant human interleukin-7 and research stability of the preparation on the basis of rIL-7. Methods. We used immortalized cells: the kidneys of dogs, the bovine kidneys and kidneys of African green monkey Vero. The following viruses were used: hepatitis C virus surrogate (bovine viral diarrhea virus, BVDV), influenza virus (strain A/FM/1/47 (H1N1)), herpes simplex virus type 2 (HSV-2) (BH strain). To determine the antiviral activity of rIL-7 in vitro conditions using daily, immortalized cells. Cells were grown in RPMI-1640 medium. Results. It was shown that rIL-7 in buffer stabilizing solutions and the culture medium after 1 week of storage was active at a dilution of 0.003 g/ml against BVDV. The study results of antiviral activity of rIL-7 drug in buffer solutions and culture medium against influenza virus A/FM/H1N1 can conclude that storage of the drug in buffer solution and in the intact state at 4 °C for one week has not affected its antiviral activity. It was shown that antiherpetic activity of preparations after 1 week of storage at 4 °C in buffer stabilizing solutions and intact state remained effective. The antiviral activity of drugs in a stabilizing solution has been persisted for 3 months at 4 °C, and in the intact state of rIL-7 lost its antiviral activity after 1 week against the herpes virus, and after 1 month regarding BVDV. Conclusions. Methods for assessing the antiviral activity of rIL-7 towards BVDV, influenza virus, and HSV-2 were developed. It has been proven that the stabilizing buffer solutions proposed by us provide a high level of biological activity of rIL-7 preparations during storage at 4 °C for 3 months, which is a prerequisite for the development of liquid dosage forms of pharmaceutical preparations on their basis.

Mefenamic acid in combination with ribavirin shows significant effects in reducing chikungunya virus infection in vitro and in vivo

Chikungunya virus (CHIKV) infection is a persistent problem worldwide due to efficient adaptation of the viral vectors, Aedes aegypti and Aedes albopictus mosquitoes. Therefore, the absence of effective anti-CHIKV drugs to combat chikungunya outbreaks often leads to a significant impact on public health care. In this study, we investigated the antiviral activity of drugs that are used to alleviate infection symptoms, namely, the non-steroidal anti-inflammatory drugs (NSAIDs), on the premise that active compounds with potential antiviral and anti-inflammatory activities could be directly subjected for human use to treat CHIKV infections. Amongst the various NSAID compounds, Mefenamic acid (MEFE) and Meclofenamic acid (MECLO) showed considerable antiviral activity against viral replication individually or in combination with the common antiviral drug, Ribavirin (RIBA). The 50% effective concentration (EC50) was estimated to be 13 μM for MEFE, 18 μM for MECLO and 10 μM for RIBA, while MEFE + RIBA (1:1) exhibited an EC50 of 3 μM, and MECLO + RIBA (1:1) was 5 μM. Because MEFE is commercially available and its synthesis is easier compared with MECLO, MEFE was selected for further in vivo antiviral activity analysis. Treatment with MEFE + RIBA resulted in a significant reduction of hypertrophic effects by CHIKV on the mouse liver and spleen. Viral titre quantification in the blood of CHIKV-infected mice through the plaque formation assay revealed that treatment with MEFE + RIBA exhibited a 6.5-fold reduction compared with untreated controls. In conclusion, our study demonstrated that MEFE in combination with RIBA exhibited significant anti-CHIKV activity by impairing viral replication in vitro and in vivo. Indeed, this finding may lead to an even broader application of these combinatorial treatments against other viral infections.

Development and characterization of a replicon-based phenotypic assay for assessing HCV NS4B from clinical isolates

The hepatitis C virus (HCV) NS4B inhibitors have shown potent inhibition of HCV replication in vitro. To assess the effect of viral diversity on the susceptibility to NS4B inhibitors, genotype (GT)-specific GT1a and GT1b replicon shuttle vectors were designed and created for cloning HCV NS4B genes from clinical isolates. For the GT1b NS4B shuttle vector, the S2204I adaptive mutation was introduced in NS5A to improve replication due to the replacement of the K1846T adaptive mutation in NS4B with NS4B from the clinical isolates. In addition to the adaptive mutations, a newly identified Huh-7 cell line, Huh-7-1C, which is highly permissive for both GT1a and GT1b replication, was used to further enhance the replication levels. HCV NS4B gene from clinical isolates was amplified and inserted into the corresponding GT1a and GT1b modified lab strain chimeric replicons. GT1a and GT1b chimeric replicons expressing diverse NS4B genes from corresponding subtypes of clinical isolates replicated at highly efficient levels for phenotypic analysis. Due to natural variation in their amino acid residues in NS4B, these isolates displayed varying drug susceptibilities to an NS4B inhibitor. In mixed populations with wild-type, the sensitivity of resistance detection of NS4B resistant mutants H94R and V105M was between 20% and 80%. The chimeric shuttle vectors can be used to characterize the activity of antiviral drugs targeting NS4B from diverse natural clinical isolates and aid in the development of novel compounds against HCV NS4B.

Antiviral activity of Ouyi Antipyretic detoxicate soft capsule against influenza a virus H1N1 in vitro

Our study aims to evaluate the antiviral effects of Ouyi antipyretic detoxicate soft capsule against influenza A virus H1N1 in vivo, so as to find an effective Chinese medicinal formulae for the treatment of the virus infection, which may lay a theoretical foundation for clinic treatment of patient infected with Influenza A Virus H1N1. With the observation of cytopathic effect (CPE) that induced by virus ,we investigated viral inhibition rate by MTT colorimetric assay and valued antiviral activity of drugs by therapeutic index (TI) . Meanwhile, Oseltamivir phosphate capsule (Tamiflu) was used as positive control , we carried out experiments through the three ways of preventive effect, direct inactivation and propagation inhibition. Ouyi antipyretic detoxicate soft capsule could effectively inhibit cytopathic effect (CPE) that induced by Influenza A Virus H1N1. The preventive effect, direct inactivation , and inhibition of endogenous multiplication of Ouyi antipyretic detoxicate soft capsule and Tamiflu against influenza A virus H1N1 were observed. And three types of action therapeutic index (TI) from Ouyi antipyretic detoxicate soft capsule were (15.5 +/- 0.71), (0.55 +/- 0.071), (6.4 +/- 1.27) severally, comparing Tamiflu with (0.4 +/- 0.14), (1.88 +/- 0.29), (4.6 +/- 0.15), respectively. Ouyi antipyretic detoxicate soft capsule showed more remarkable preventive effect than Tamiflu in vitro (P<0.01). The possible mechanism of the antiviral activity observed in our study might be the protection of the MDCK cells from viral infection by inhibiting the viral absorption. We need a further study to certify three effects in vivo.