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Entry Inhibition of Influenza Viruses with High Mannose Binding Lectin ESA-2 from the Red Alga Eucheuma serra through the Recognition of Viral Hemagglutinin.

Sato Y, Morimoto K, Kubo T, Sakaguchi T, Nishizono A, Hirayama M, Hori K - Mar Drugs (2015)

Bottom Line: Besides ESA-2, HM-binding plant lectin ConA, fucose-binding lectins such as fungal AOL from Aspergillus oryzae and AAL from Aleuria aurantia were active against H1N1-2009, but the potency of inhibition was of less magnitude compared with ESA-2.Direct interaction between ESA-2 and a viral envelope glycoprotein, hemagglutinin (HA), was demonstrated by ELISA assay.Upon treatment with ESA-2, no viral antigens were detected in the host cells, indicating that ESA-2 inhibited the initial steps of virus entry into the cells.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Pharmacy, Yasuda Women's University, 6-13-1 Yasuhigashi, Asaminami-Ku, Hiroshima 731-0153, Japan. sato-y@yasuda-u.ac.jp.

ABSTRACT
Lectin sensitivity of the recent pandemic influenza A virus (H1N1-2009) was screened for 12 lectins with various carbohydrate specificity by a neutral red dye uptake assay with MDCK cells. Among them, a high mannose (HM)-binding anti-HIV lectin, ESA-2 from the red alga Eucheuma serra, showed the highest inhibition against infection with an EC50 of 12.4 nM. Moreover, ESA-2 exhibited a wide range of antiviral spectrum against various influenza strains with EC50s of pico molar to low nanomolar levels. Besides ESA-2, HM-binding plant lectin ConA, fucose-binding lectins such as fungal AOL from Aspergillus oryzae and AAL from Aleuria aurantia were active against H1N1-2009, but the potency of inhibition was of less magnitude compared with ESA-2. Direct interaction between ESA-2 and a viral envelope glycoprotein, hemagglutinin (HA), was demonstrated by ELISA assay. This interaction was effectively suppressed by glycoproteins bearing HM-glycans, indicating that ESA-2 binds to the HA of influenza virus through HM-glycans. Upon treatment with ESA-2, no viral antigens were detected in the host cells, indicating that ESA-2 inhibited the initial steps of virus entry into the cells. ESA-2 would thus be useful as a novel microbicide to prevent penetration of viruses such as HIV and influenza viruses to the host cells.

No MeSH data available.


Related in: MedlinePlus

(A) Inhibition of influenza virus invasion into MDCK cells by ESA-2. MDCK cells grown on cover slips were infected with A/Udorn/72(H3N2) in the presence of 200 nM ESA-2 or 1 mM amantadine. After 24 h post infection, the cells were fixed and the viral antigens in the cells were visualized with anti-hemagglutinin (HA) mouse monoclonal antibody followed by fluorescein isothiocyanate (FITC)-conjugated goat anti-mouse IgG. Nuclei within the cells were stained with DAPI (200× magnification); (B) Effect of ESA-2 addition after post-infection. H292 cells were infected with A/Udorn/72(H3N2) and after 1 or 2 h post-infection, 200 nM ESA-2 was added to the cells. Cell viability was evaluated by amide black staining followed by quantitation by image processing.
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marinedrugs-13-03454-f003: (A) Inhibition of influenza virus invasion into MDCK cells by ESA-2. MDCK cells grown on cover slips were infected with A/Udorn/72(H3N2) in the presence of 200 nM ESA-2 or 1 mM amantadine. After 24 h post infection, the cells were fixed and the viral antigens in the cells were visualized with anti-hemagglutinin (HA) mouse monoclonal antibody followed by fluorescein isothiocyanate (FITC)-conjugated goat anti-mouse IgG. Nuclei within the cells were stained with DAPI (200× magnification); (B) Effect of ESA-2 addition after post-infection. H292 cells were infected with A/Udorn/72(H3N2) and after 1 or 2 h post-infection, 200 nM ESA-2 was added to the cells. Cell viability was evaluated by amide black staining followed by quantitation by image processing.

Mentions: To examine whether ESA-2 inhibits virus entry into the cells, cellular distribution of viral antigen either in the presence or absence of ESA-2 was observed by immunofluorescence microscopy. In the presence of 200 nM ESA-2, no viral antigens were detected in the MDCK cells infected with A/Udorn/72 (Figure 3A). In addition, no cytopathic effect (CPE) in the infected cells was observed. In contrast, 1 mM amantadine, which is an M2 channel blocker but not an entry inhibitor of influenza virus, failed to block the viral infection in the host cells. To test whether ESA-2 inhibits initial virus entry but not another early step of viral replication, effect of ESA-2 was determined after post-infection. The data in Figure 3B clearly showed that ESA-2 failed to inhibit infection when it was administered to the cells after 1 or 2 h post-infection. In contrast, ESA-2 effectively inhibited virus replication when it was added to the cells simultaneously with the virus. These results indicate ESA-2 acts as an entry inhibitor.


Entry Inhibition of Influenza Viruses with High Mannose Binding Lectin ESA-2 from the Red Alga Eucheuma serra through the Recognition of Viral Hemagglutinin.

Sato Y, Morimoto K, Kubo T, Sakaguchi T, Nishizono A, Hirayama M, Hori K - Mar Drugs (2015)

(A) Inhibition of influenza virus invasion into MDCK cells by ESA-2. MDCK cells grown on cover slips were infected with A/Udorn/72(H3N2) in the presence of 200 nM ESA-2 or 1 mM amantadine. After 24 h post infection, the cells were fixed and the viral antigens in the cells were visualized with anti-hemagglutinin (HA) mouse monoclonal antibody followed by fluorescein isothiocyanate (FITC)-conjugated goat anti-mouse IgG. Nuclei within the cells were stained with DAPI (200× magnification); (B) Effect of ESA-2 addition after post-infection. H292 cells were infected with A/Udorn/72(H3N2) and after 1 or 2 h post-infection, 200 nM ESA-2 was added to the cells. Cell viability was evaluated by amide black staining followed by quantitation by image processing.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4483639&req=5

marinedrugs-13-03454-f003: (A) Inhibition of influenza virus invasion into MDCK cells by ESA-2. MDCK cells grown on cover slips were infected with A/Udorn/72(H3N2) in the presence of 200 nM ESA-2 or 1 mM amantadine. After 24 h post infection, the cells were fixed and the viral antigens in the cells were visualized with anti-hemagglutinin (HA) mouse monoclonal antibody followed by fluorescein isothiocyanate (FITC)-conjugated goat anti-mouse IgG. Nuclei within the cells were stained with DAPI (200× magnification); (B) Effect of ESA-2 addition after post-infection. H292 cells were infected with A/Udorn/72(H3N2) and after 1 or 2 h post-infection, 200 nM ESA-2 was added to the cells. Cell viability was evaluated by amide black staining followed by quantitation by image processing.
Mentions: To examine whether ESA-2 inhibits virus entry into the cells, cellular distribution of viral antigen either in the presence or absence of ESA-2 was observed by immunofluorescence microscopy. In the presence of 200 nM ESA-2, no viral antigens were detected in the MDCK cells infected with A/Udorn/72 (Figure 3A). In addition, no cytopathic effect (CPE) in the infected cells was observed. In contrast, 1 mM amantadine, which is an M2 channel blocker but not an entry inhibitor of influenza virus, failed to block the viral infection in the host cells. To test whether ESA-2 inhibits initial virus entry but not another early step of viral replication, effect of ESA-2 was determined after post-infection. The data in Figure 3B clearly showed that ESA-2 failed to inhibit infection when it was administered to the cells after 1 or 2 h post-infection. In contrast, ESA-2 effectively inhibited virus replication when it was added to the cells simultaneously with the virus. These results indicate ESA-2 acts as an entry inhibitor.

Bottom Line: Besides ESA-2, HM-binding plant lectin ConA, fucose-binding lectins such as fungal AOL from Aspergillus oryzae and AAL from Aleuria aurantia were active against H1N1-2009, but the potency of inhibition was of less magnitude compared with ESA-2.Direct interaction between ESA-2 and a viral envelope glycoprotein, hemagglutinin (HA), was demonstrated by ELISA assay.Upon treatment with ESA-2, no viral antigens were detected in the host cells, indicating that ESA-2 inhibited the initial steps of virus entry into the cells.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Pharmacy, Yasuda Women's University, 6-13-1 Yasuhigashi, Asaminami-Ku, Hiroshima 731-0153, Japan. sato-y@yasuda-u.ac.jp.

ABSTRACT
Lectin sensitivity of the recent pandemic influenza A virus (H1N1-2009) was screened for 12 lectins with various carbohydrate specificity by a neutral red dye uptake assay with MDCK cells. Among them, a high mannose (HM)-binding anti-HIV lectin, ESA-2 from the red alga Eucheuma serra, showed the highest inhibition against infection with an EC50 of 12.4 nM. Moreover, ESA-2 exhibited a wide range of antiviral spectrum against various influenza strains with EC50s of pico molar to low nanomolar levels. Besides ESA-2, HM-binding plant lectin ConA, fucose-binding lectins such as fungal AOL from Aspergillus oryzae and AAL from Aleuria aurantia were active against H1N1-2009, but the potency of inhibition was of less magnitude compared with ESA-2. Direct interaction between ESA-2 and a viral envelope glycoprotein, hemagglutinin (HA), was demonstrated by ELISA assay. This interaction was effectively suppressed by glycoproteins bearing HM-glycans, indicating that ESA-2 binds to the HA of influenza virus through HM-glycans. Upon treatment with ESA-2, no viral antigens were detected in the host cells, indicating that ESA-2 inhibited the initial steps of virus entry into the cells. ESA-2 would thus be useful as a novel microbicide to prevent penetration of viruses such as HIV and influenza viruses to the host cells.

No MeSH data available.


Related in: MedlinePlus