High mannose-specific lectin (KAA-2) from the red alga Kappaphycus alvarezii potently inhibits influenza virus infection in a strain-independent manner

• Published in: Biochemical and biophysical research communications Vol. 405; no. 2; pp. 291 - 296
• Main Authors: Sato, Yuichiro, Morimoto, Kinjiro, Hirayama, Makoto, Hori, Kanji
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 11.02.2011
• Subjects: Animals; Anti-influenza activity; Antiviral Agents - chemistry; Antiviral Agents - pharmacology; Cell Line; Chick Embryo; Dogs; Eucheuma serra; Hemagglutinin Glycoproteins, Influenza Virus - metabolism; High mannose type N-glycan; Human immunodeficiency virus; Humans; Influenza A Virus, H1N1 Subtype - drug effects; Influenza A Virus, H3N2 Subtype - drug effects; Influenza virus; Influenza, Human - virology; Kappaphycus alvarezii; Lectin; Lectins - chemistry; Lectins - metabolism; Lectins - pharmacology; Mannose-Binding Lectins - chemistry; Mannose-Binding Lectins - metabolism; Mannose-Binding Lectins - pharmacology; Red algae; Rhodophyta; Lectin; MVL; Anti-influenza activity; MVN; NR; HM; Red algae; SVN; CV-N; ESA-2; OAA; KAA-2; PA; SP-D; HA; High mannose type N-glycan
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2011.01.031

► The red algal lectin KAA-2 specifically binds to high mannose type N-glycans. ► KAA-2 shows a broad spectrum of anti-influenza activity strain-independently. ► The antiviral activity of KAA-2 is very strong with EC 50s of low nanomolar range. ► KAA-2 effectively inactivates recent emerged swine origin H1N1 influenza virus. ► KAA-2 inhibits virus entry into the cells by binding to viral envelope glycoproteins. The carbohydrate binding profile of the red algal lectin KAA-2 from Kappaphycus alvarezii was evaluated by a centrifugal ultrafiltration–HPLC method using pyridylaminated oligosaccharides. KAA-2 bound exclusively to high mannose type N-glycans, but not to other glycans such as complex type, hybrid type, or the pentasaccharide core of N-glycans. This lectin exhibited a preference for an exposed α1–3 Man on a D2 arm in a similar manner to Eucheuma serra agglutinin (ESA-2), which shows various biological activities, such as anti-HIV and anti-carcinogenic activity. We tested the anti-influenza virus activity of KAA-2 against various strains including the recent pandemic H1N1-2009 influenza virus. KAA-2 inhibited infection of various influenza strains with EC 50s of low nanomolar levels. Immunofluorescence microscopy using an anti-influenza antibody demonstrated that the antiviral activity of KAA-2 was exerted by interference with virus entry into host cells. This mechanism was further confirmed by the evidence of direct binding of KAA-2 to a viral envelope protein, hemagglutinin (HA), using an ELISA assay. These results indicate that this lectin would be useful as a novel antiviral reagent for the prevention of infection.