title: High mannose-specific lectin (KAA-2) from the red alga Kappaphycus alvarezii potently inhibits influenza virus infection in a strain-independent manner.
abstract: 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 EC50s 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.
authors.affiliation: Faculty of Pharmacy, Yasuda Women's University, 6-13-1 Yasuhigashi, Asaminami, Hiroshima 731-0153, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Sato
authors.forename: Kinjiro
authors.initials: K
authors.lastname: Morimoto
authors.forename: Makoto
authors.initials: M
authors.lastname: Hirayama
authors.forename: Kanji
authors.initials: K
authors.lastname: Hori
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000737:chemistry / Q000494:pharmacology*; D002460:Cell Line; D002642:Chick Embryo; D004285:Dogs; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000378:metabolism; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects*; D053122:Influenza A Virus, H3N2 Subtype / Q000187:drug effects*; D007251:Influenza, Human / Q000821:virology*; D037102:Lectins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D037241:Mannose-Binding Lectins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D000461:Rhodophyta
chemical_list: D000998:Antiviral Agents; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D037102:Lectins; D037241:Mannose-Binding Lectins