Narcissus tazetta lectin shows strong inhibitory effects against respiratory syncytial virus, influenza A (H1N1, H3N2, H5N1) and B viruses

Abstract

A mannose-binding lectin (Narcissus tazetta lectin [NTL]) with potent antiviral activity was isolated and purified from the bulbs of the Chinese daffodil Narcissus tazetta var. chinensis, using ion exchange chromatography on diethylaminoethyl (DEAE)-cellulose, affinity chromatography on mannose-agarose and fast protein liquid chromatography (FPLC)-gel filtration on Superose 12. The purified lectin was shown to have an apparent molecular mass of 26 kDa by gel filtration and 13 kDa by SDS-PAGE, indicating that it is probably a dimer with two identical subunits. The cDNA-derived amino acid sequence of NTL as determined by molecular cloning also reveals that NTL protein contains a mature polypeptide consisting of 105 amino acids and a C-terminal peptide extension. Three-dimensional modelling study demonstrated that the NTL primary polypeptide contains three subdomains, each with a conserved mannose-binding site. It shows a high homology of about 60%-80% similarity with the existing monocot mannose-binding lectins. NTL could significantly inhibit plaque formation by the human respiratory syncytial virus (RSV) with an IC50 of 2.30 microg/ml and exhibit strong antiviral properties against influenza A (H1N1, H3N2, H5N1) and influenza B viruses with IC50 values ranging from 0.20 microg/ml to 1.33 microg/ml in a dose-dependent manner. It is worth noting that the modes of antiviral action of NTL against RSV and influenza A virus are significantly different. NTL is effective in the inhibition of RSV during the whole viral infection cycle, but the antiviral activity of NTL is mainly expressed at the early stage of the viral cycle of influenza A (H1N1) virus. NTL with a high selective index (SI=CC50/IC50 > or = 141) resulting from its potent antiviral activity and low cytotoxicity demonstrates a potential for biotechnological development as an antiviral agent.

Potent antiviral activity of carbohydrate-specific algal and leguminous lectins from the Brazilian biodiversity

“…6 According to the literature, humans and other vertebrates including wild birds, bats and pigs, can contract these type of viruses. These striking differences in antiviral potential between different strains of influenza virus may most likely be due to (often subtle) 56 which is about 10-fold less potent than our findings for DLasiL against RSV (EC 50 = 9 nM). They can also cause highly destructive loss in domestic poultry and pose risks for humans.…”

Biochemical characterisation of lectin from Indian hyacinth plant bulbs with potential inhibitory action against human cancer cells

“…Among the two cell lines we observe higher sensitivity of lectin mediated apoptotic response in Caco-2 cells with an IC 50 value of 127 ± 5 g/mL. This is the first report from hyacinth lectin on antiproliferative activity although other lectins from different plant sources have been reported for their anti-proliferative activity [42].…”

Glycosylation of dengue virus glycoproteins and their interactions with carbohydrate receptors: possible targets for antiviral therapy

“…Several CBAs with unique properties and specificities (Table 3) have been identified and used to block viruses. Most of these lectins bind specifically to mannose moieties, ranging from terminal mannosyl residues to high-mannose glycans, which are targeted by a wide range of viruses [94][95][96][97][98][99][100][101][102][103][104][105][106].…”