IFN-λ1 Displays Various Levels of Antiviral Activity In Vitro in a Select Panel of RNA Viruses

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.

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In vitro Assessment of Antiviral Effect of Natural Compounds on Porcine Epidemic Diarrhea Coronavirus

Frontiers in Veterinary Science ◽

10.3389/fvets.2021.652000 ◽

2021 ◽

Vol 8 ◽

Author(s):

Manuel Gómez-García ◽

Héctor Puente ◽

Héctor Argüello ◽

Óscar Mencía-Ares ◽

Pedro Rubio ◽

...

Keyword(s):

Antiviral Activity ◽

Formic Acid ◽

Antiviral Agents ◽

Antiviral Effect ◽

Vero Cells ◽

Optical Microscope ◽

Dependent Manner ◽

Diarrhea Virus ◽

Porcine Epidemic Diarrhea

Organic acid and essential oils (EOs), well-known antimicrobials, could also possess antiviral activity, a characteristic which has not been completely addressed up to now. In this study, the effect of two organic acids (formic acid and sodium salt of coconut fatty acid distillates) and two single EO compounds (thymol and cinnamaldehye) was evaluated against porcine epidemic diarrhea virus (PEDV). The concentration used for each compound was established by cytotoxicity assays in Vero cells. The antiviral activity was then evaluated at three multiplicities of infection (MOIs) through visual cytopathic effect (CPE) evaluation and an alamarBlue assay as well as real-time reverse-transcription PCR (RT-qPCR) and viral titration of cell supernatants. Formic acid at at a dose of 1,200 ppm was the only compound which showed antiviral activity, with a weak reduction of CPE caused by PEDV. Through the alamarBlue fluorescence assay, we showed a significant anti-CPE effect of formic acid which could not be observed by using an inverted optical microscope. RT-qPCR and infectivity analysis also showed that formic acid significantly reduced viral RNA and viral titers in a PEDV MOI-dependent manner. Our results suggest that the antiviral activity of formic acid could be associated to its inhibitory effect on viral replication. Further studies are required to explore the anti-PEDV activity of formic acid under field conditions alone or together with other antiviral agents.

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MOXIDECTIN AND IVERMECTIN INHIBIT SARS-COV-2 REPLICATION IN VERO E6 CELLS BUT NOT IN HUMAN PRIMARY AIRWAY EPITHELIUM CELLS

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01543-21 ◽

2021 ◽

Author(s):

Nilima Dinesh Kumar ◽

Bram M. ter Ellen ◽

Ellen M. Bouma ◽

Berit Troost ◽

Denise P. I. van de Pol ◽

...

Keyword(s):

Antiviral Activity ◽

Antiviral Effect ◽

Vero Cells ◽

In Vitro Models ◽

World Health ◽

Current Evidence ◽

High Dose ◽

Health Organization

Antiviral therapies are urgently needed to treat and limit the development of severe COVID-19 disease. Ivermectin, a broad-spectrum anti-parasitic agent, has been shown to have anti-SARS-CoV-2 activity in Vero cells at a concentration of 5 μM. These limited in vitro results triggered the investigation of ivermectin as a treatment option to alleviate COVID-19 disease. In April 2021, the World Health Organization stated, however, the following: “the current evidence on the use of ivermectin to treat COVID-19 patients is inconclusive”. It is speculated that the in vivo concentration of ivermectin is too low to exert a strong antiviral effect. Here, we performed a head-to head comparison of the antiviral activity of ivermectin and the structurally related, but metabolically more stable, moxidectin in multiple in vitro models of SARS-CoV-2 infection, including physiologically relevant human respiratory epithelial cells. Both moxidectin and ivermectin exhibited antiviral activity in Vero E6 cells. Subsequent experiments revealed that the compounds predominantly act on a step after virus cell entry. Surprisingly, however, in human airway-derived cell models, moxidectin and ivermectin failed to inhibit SARS-CoV-2 infection, even at a concentration of 10 μM. These disappointing results call for a word of caution in the interpretation of anti-SARS-CoV-2 activity of drugs solely based on Vero cells. Altogether, these findings suggest that, even by using a high-dose regimen of ivermectin or switching to another drug in the same class are unlikely to be useful for treatment against SARS-CoV-2 in humans.

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The Antimicrobial and Antiviral Activity of Polyphenols from Almond (Prunus dulcis L.) Skin

Nutrients ◽

10.3390/nu11102355 ◽

2019 ◽

Vol 11 (10) ◽

pp. 2355 ◽

Cited By ~ 13

Author(s):

Maria Musarra-Pizzo ◽

Giovanna Ginestra ◽

Antonella Smeriglio ◽

Rosamaria Pennisi ◽

Maria Teresa Sciortino ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Antiviral Activity ◽

Plaque Assay ◽

Antiviral Effect ◽

Prunus Dulcis ◽

Culture Collection ◽

Type I ◽

Mrsa Strains ◽

Simplex Virus

Due to their antimicrobial and antiviral activity potential in vitro, polyphenols are gaining a lot of attention from the pharmaceutical and healthcare industries. A novel antiviral and antimicrobial approach could be based on the use of polyphenols obtained from natural sources. Here, we tested the antibacterial and antiviral effect of a mix of polyphenols present in natural almond skin (NS MIX). The antimicrobial potential was evaluated against the standard American Type Culture Collection (ATCC) and clinical strains of Staphylococcus aureus, including methicillin-resistant (MRSA) strains, by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Herpes simplex virus type I was used for the antiviral assessment of NS MIX by plaque assay. Furthermore, we evaluated the expression of viral cascade antigens. NS MIX exhibited antimicrobial (MIC values of 0.31–1.25 mg/ml) and antiviral activity (decrease in the viral titer ** p < 0.01, and viral DNA accumulation * p < 0.05) against Staphylococcus aureus and HSV-1, respectively. Amongst the isolated compounds, the aglycones epicatechin and catechin showed the greatest activity against S. aureus ATCC 6538P (MIC values of 0.078–0.15 and 0.15 mg/ml, respectively), but were not active against all the other strains. These results could be used to develop novel products for topical use.

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Inactivation of Herpes Simplex Virus by Photosensitizing Anthraquinones Isolated from Heterophyllaea pustulata

Planta Medica ◽

10.1055/a-1345-6831 ◽

2021 ◽

Author(s):

M. Laura Mugas ◽

Juliana Marioni ◽

Florencia Martinez ◽

Juan J. Aguilar ◽

José L. Cabrera ◽

...

Keyword(s):

Herpes Simplex Virus ◽

Herpes Simplex ◽

Antiviral Activity ◽

Antiviral Effect ◽

Neutral Red ◽

Host Cells ◽

Type I ◽

Antiherpetic Activity ◽

Simplex Virus

Abstract Heterophyllaea pustulata is a phototoxic plant from Argentina. Aerial parts extracts, high in photosensitizing anthraquinones, have shown in vitro antiviral activity. The purpose of this study was to study the antiherpetic activity of the main purified anthraquinones, even evaluating their competence as photodynamic sensitizers to photo-stimulate the antiviral effect. In vitro antiviral activity against Herpes Simplex virus type I and the photo-inactivation of viral particle were studied by the Neutral Red uptake test and observation of the cytopathic effect. Rubiadin 1-methyl ether and 5,5′-bisoranjidiol produced a significant effect (≥ 80% inhibition) with minimal damage to host cells (subtoxic concentration). Anthraquinones with poor antiherpetic activity at its maximum noncytotoxic concentration showed an important photo-stimulated effect, such is the case of soranjidiol and 5,5′-bisoranjidiol (28.0 ± 6.3 vs. 81.8 ± 2.1% and 15.5 ± 0.3 vs. 89.8 ± 1.7%, respectively). The study also proved the decrease of viral particles, necessary to reduce infection. Therefore, photosensitizing anthraquinones from natural resources could be proposed to develop new treatments for localized viral lesions with antimicrobial photodynamic therapy.

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Moxidectin and ivermectin inhibit SARS-CoV-2 replication in Vero E6 cells but not in human primary airway epithelium cells

10.1101/2021.05.17.444467 ◽

2021 ◽

Author(s):

Nilima Dinesh Kumar ◽

Bram Ter Ellen ◽

Ellen M Bouma ◽

Berit Troost ◽

Denise P. I van de Pol ◽

...

Keyword(s):

Antiviral Activity ◽

Antiviral Effect ◽

Vero Cells ◽

In Vitro Models ◽

World Health ◽

Current Evidence ◽

High Dose ◽

Health Organization

Antiviral therapies are urgently needed to treat and limit the development of severe COVID-19 disease. Ivermectin, a broad-spectrum anti-parasitic agent, has been shown to have anti-SARS-CoV-2 activity in Vero cells at a concentration of 5 micromolar. These in vitro results triggered the investigation of ivermectin as a treatment option to alleviate COVID-19 disease. In April 2021, the World Health Organization stated, however, the following: "the current evidence on the use of ivermectin to treat COVID-19 patients is inconclusive". It is speculated that the in vivo concentration of ivermectin is too low to exert a strong antiviral effect. Here, we performed a head-to head comparison of the antiviral activity of ivermectin and a structurally related, but metabolically more stable, moxidectin in multiple in vitro models of SARS-CoV-2 infection, including physiologically relevant human respiratory epithelial cells. Both moxidectin and ivermectin exhibited antiviral activity in Vero E6 cells. Subsequent experiments revealed that the compounds predominantly act on a step after virus cell entry. Surprisingly, however, in human airway-derived cell models, moxidectin and ivermectin failed to inhibit SARS-CoV-2 infection, even at a concentration of 10 micromolar. These disappointing results calls for a word of caution in the interpretation of anti-SARS-CoV-2 activity of drugs solely based on Vero cells. Altogether, these findings suggest that, even by using a high-dose regimen of ivermectin or switching to another drug in the same class are unlikely to be useful for treatment against SARS-CoV-2 in humans.

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Analysis of the Function of the Lymphocytic Choriomeningitis Virus S Segment Untranslated Region on Growth Capacity In Vitro and on Virulence In Vivo

Viruses ◽

10.3390/v12080896 ◽

2020 ◽

Vol 12 (8) ◽

pp. 896

Author(s):

Satoshi Taniguchi ◽

Tomoki Yoshikawa ◽

Masayuki Shimojima ◽

Shuetsu Fukushi ◽

Takeshi Kurosu ◽

...

Keyword(s):

Reverse Genetics ◽

Vero Cells ◽

Lymphocytic Choriomeningitis ◽

Lymphocytic Choriomeningitis Virus ◽

Genome Replication ◽

Growth Capacity ◽

Functional Roles ◽

Viral Genome Replication

Lymphocytic choriomeningitis virus (LCMV) is a prototypic arenavirus. The function of untranslated regions (UTRs) of the LCMV genome has not been well studied except for the extreme 19 nucleotide residues of both the 5′ and 3′ termini. There are internal UTRs composed of 58 and 41 nucleotide residues in the 5′ and 3′ UTRs, respectively, in the LCMV S segment. Their functional roles have yet to be elucidated. In this study, reverse genetics and minigenome systems were established for LCMV strain WE and the function of these regions were analyzed. It was revealed that nucleotides 20–40 and 20–38 located downstream of the 19 nucleotides in the 5′ and 3′ termini, respectively, were involved in viral genome replication and transcription. Furthermore, it was revealed that the other internal UTRs (nucleotides 41–77 and 39–60 in the 5′ and 3′ termini, respectively) in the S segment were involved in virulence in vivo, even though these regions did not affect viral growth capacity in Vero cells. The introduction of LCMV with mutations in these regions attenuates the virus and may enable the production of LCMV vaccine candidates.

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Lethal Mutagenesis of Picornaviruses with N-6-Modified Purine Nucleoside Analogues

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01056-07 ◽

2008 ◽

Vol 52 (3) ◽

pp. 971-979 ◽

Cited By ~ 35

Author(s):

Jason D. Graci ◽

Kathleen Too ◽

Eric D. Smidansky ◽

Jocelyn P. Edathil ◽

Eric W. Barr ◽

...

Keyword(s):

Rna Viruses ◽

Antiviral Agents ◽

Antiviral Effect ◽

Purine Nucleoside ◽

Nucleoside Analogues ◽

Genome Replication ◽

Purine Analogues ◽

Mutagenic Potential ◽

Lethal Mutagenesis

ABSTRACT RNA viruses exhibit extraordinarily high mutation rates during genome replication. Nonnatural ribonucleosides that can increase the mutation rate of RNA viruses by acting as ambiguous substrates during replication have been explored as antiviral agents acting through lethal mutagenesis. We have synthesized novel N-6-substituted purine analogues with ambiguous incorporation characteristics due to tautomerization of the nucleobase. The most potent of these analogues reduced the titer of poliovirus (PV) and coxsackievirus (CVB3) over 1,000-fold during a single passage in HeLa cell culture, with an increase in transition mutation frequency up to 65-fold. Kinetic analysis of incorporation by the PV polymerase indicated that these analogues were templated ambiguously with increased efficiency compared to the known mutagenic nucleoside ribavirin. Notably, these nucleosides were not efficient substrates for cellular ribonucleotide reductase in vitro, suggesting that conversion to the deoxyriboucleoside may be hindered, potentially limiting genetic damage to the host cell. Furthermore, a high-fidelity PV variant (G64S) displayed resistance to the antiviral effect and mutagenic potential of these analogues. These purine nucleoside analogues represent promising lead compounds in the development of clinically useful antiviral therapies based on the strategy of lethal mutagenesis.

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Evaluation of antiviral activity of Manuka honey against SARS-CoV-2.

10.29117/quarfe.2021.0113 ◽

2021 ◽

Author(s):

Israa Elbashir ◽

Aisha Aisha Nasser J M Al-Saei ◽

Paul Thornalley ◽

Naila Rabbani

Keyword(s):

Logistic Regression ◽

Antiviral Activity ◽

Cytopathic Effect ◽

Antiviral Treatment ◽

Antiviral Effect ◽

Vero Cells ◽

Manuka Honey ◽

Virus Control ◽

Arginine Residues

Background and aims: In 2020 a global pandemic was declared caused by the severe acute respiratory syndrome coronavirus (SARS-CoV-2). The pandemic is still ongoing and continues to cause considerable mortality and morbidity world-wide and new variants of the virus are emerging. Rapid development and rollout of vaccines for SARS-CoV-2 is in progress to counter the pandemic but has been tempered by the emergence of new SARS-CoV-2 variants, many of which exhibit reduced vaccine effectiveness. To date there is no approved antiviral treatment for coronavirus disease 2019 (COVID-19). Several studies have shown that Manuka honey has virucidal/antiviral effect. Methylglyoxal (MG), a bioactive component in Manuka honey, has antiviral activity in vitro. MG may modify arginine residues in the functional domains of viral spike and nucleocapsid proteins, resulting in loss of charge, protein misfolding and inactivation. The aim of this study was to characterize the antiviral activity of Manuka honey against SARS-CoV-2 in vitro Materials and methods: Wild-type SARS-CoV-2 with titers of multiplicities of infection (MOI) 0.1 and 0.05 were incubated with 2-fold serial dilutions of 250+ Manuka honey (equivalent to 250 to 31 µM) in infection medium (Dulbecco's Modified Eagle Medium + 2% fetal bovine serum + 100 units/ml penicillin + 100 µg/ml streptomycin) for 3 h. Manuka honey treated and untreated control SARS-CoV-2 was incubated with confluent cultures of Vero cells in vitro for 1 h, cultures washed with phosphate-buffered saline and incubated in fresh infection medium at 37°C for 4 - 5 days until 70% of virus control cells displayed cytopathic effect. We also studied the effect of scavenging MG in Manuka Honey with aminoguanidine (AG; 500 µM) on virucidal activity. The antiviral activity of MG was judged by median tissue culture infectious dose (TCID50) assays. Data analysis was by logistic regression. TCID50 (mean ± SD) was deduced by interpolation. Results: Diluted Manuka honey inhibited SARS-CoV-2 replication in Vero cells. SARS-CoV-2 was incubated in diluted Manuka honey in medium at 37°C for 3 h before adding to Vero cells. Manuka honey dilutions down to 125 µM MG equivalents completely inhibited cytopathic effect of SARS-CoV-2 whereas 31.25 µM and 62.5 µM MG equivalents had limited effect. Logistic regression and interpolation of the cytopathic effect indicated that the TCID50 = 72 ± 2 µM MG equivalents for MOI of 0.1. Prior scavenging of MG by addition of AG resulted in virus replication levels equivalent to those seen in the virus control without AG. Conclusion: Manuka honey has antiviral activity against SARS-CoV-2 when incubated with the virus in cell-free media at no greater than ca. 40-fold dilutions of 250+ grade. Anti-viral activity was inhibited by AG, consistent with the anti-viral effect being mediated by MG. Manuka honey dilutions in MG equivalents had similar antiviral effect compared to authentic MG, also consistent with MG content of Manuka honey mediating the antiviral effect. Whilst Manuka honey may inactivate SARS-CoV-2 in cell-free culture medium, its antiviral activity in vivo for other than topical application may be limited because of the rapid metabolism of MG by the glyoxalase system and limited bioavailability of oral MG.

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A Herbal Mixture Formula of OCD20015-V009 Prophylactic Administration to Enhance Interferon-Mediated Antiviral Activity Against Influenza A Virus

Frontiers in Pharmacology ◽

10.3389/fphar.2021.764297 ◽

2021 ◽

Vol 12 ◽

Author(s):

Eun-Bin Kwon ◽

You-Chang Oh ◽

Youn-Hwan Hwang ◽

Wei Li ◽

Seok-Man Park ◽

...

Keyword(s):

Antiviral Activity ◽

Influenza A Virus ◽

Influenza A ◽

Type I ◽

Protective Effects ◽

Murine Macrophages ◽

Prophylactic Administration ◽

Pre Treatment

OCD20015-V009 is an herbal mix of water-extracted Ginseng Radix, Poria (Hoelen), Rehmanniae Radix, Adenophorae Radix, Platycodi Radix, Crataegii Fructus, and Astragali Radix. In this study, its in vitro and in vivo antiviral activity and mechanisms against the influenza A virus were evaluated using a GFP-tagged influenza A virus (A/PR/8/34-GFP) to infect murine macrophages. We found that OCD20015-V009 pre-treatment substantially reduced A/PR/8/34-GFP replication. Also, OCD20015-V009 pre-treatment increased the phosphorylation of type-I IFN-related proteins TBK-1 and STAT1 and the secretion of pro-inflammatory cytokines TNF-α and IL-6 by murine macrophages. Moreover, OCD20015-V009 prophylactic administration increased IFN-stimulated genes-related 15, 20, and 56 and IFN-β mRNA in vitro. Thus, OCD20015-V009 likely modulates murine innate immune response via macrophages. This finding is potentially useful for developing prophylactics or therapeutics against the influenza A virus. Furthermore, pre-treatment with OCD20015-V009 decreased the mortality of the mice exposed to A/PR/8/34-GFP by 20% compared to that in the untreated animals. Thus, OCD20015-V009 stimulates the antiviral response in murine macrophages and mice to viral infections. Additionally, we identified chlorogenic acid and ginsenoside Rd as the antiviral components in OCD20015-V009. Further investigations are needed to elucidate the protective effects of active components of OCD20015-V009 against influenza A viruses.

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Development of a Mucus Gland Bioreactor in Loach Paramisgurnus dabryanus

International Journal of Molecular Sciences ◽

10.3390/ijms22020687 ◽

2021 ◽

Vol 22 (2) ◽

pp. 687

Author(s):

Tong Zhou ◽

Bolan Zhou ◽

Yasong Zhao ◽

Qing Li ◽

Guili Song ◽

...

Keyword(s):

Antiviral Activity ◽

Grass Carp ◽

Single Copy ◽

Type I ◽

Western Blots ◽

Paramisgurnus Dabryanus ◽

Expression Activity ◽

Transgenic Construct ◽

Mucus Gland

Most currently available bioreactors have some defects in the expression, activity, or purification of target protein and peptide molecules, whereas the mucus gland of fish can overcome these defects to become a novel bioreactor for the biopharmaceutical industry. In this study, we have evaluated the practicability of developing a mucus gland bioreactor in loach (Paramisgurnus dabryanus). A transgenic construct pT2-krt8-IFN1 was obtained by subcloning the promoter of zebrafish keratin 8 gene and the type I interferon (IFN1) cDNA of grass carp into the SB transposon. The IFN1 expressed in CIK cells exhibited an antiviral activity against the replication of GCRV873 and activated two genes downstream of JAK-STAT signaling pathway. A transgenic loach line was then generated by microinjection of the pT2-krt8-IFN1 plasmids and in vitro synthesized capped SB11 mRNA. Southern blots indicated that a single copy of IFN1 gene was stably integrated into the genome of transgenic loach. The expression of grass carp IFN1 in transgenic loaches was detected with RT-PCR and Western blots. About 0.0825 µg of grass carp IFN1 was detected in 20 µL mucus from transgenic loaches. At a viral titer of 1 × 103 PFU/mL, plaque numbers on plates containing mucus from transgenic loaches reduced by 18% in comparison with those of the control, indicating that mucus of IFN1-transgenic loaches exhibited an antiviral activity. Thus, we have successfully created a mucus gland bioreactor that has great potential for the production of various proteins and peptides.

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