Anti-influenza virus activity of high-mannose binding lectins derived from genus Pseudomonas

Abstract

Lectin PFL binding high-mannose glycan derived from Pseudomonas fluorescens and other homologous lectins: PML derived from Pseudomonas mandelii and PTL derived from Pseudomonas taiwanensis were examined for antiviral activity. The cDNA of these lectin genes were synthesized, cloned, expressed in Escherichia coli. The expressed lectins were purified by gel filtrations, and supplied to cultures infected with several strains of influenza virus. These three lectins have inhibited propagation of influenza viruses with a similar extent, 50% of inhibition-dose was around ten nanomolar concentration. An immunofluorescent microscopy, a microarray analysis, and several infection experiments with different time periods of lectin addition or using the competitor substrates indicated that binding of these lectins with high-mannose glycan on HA protein of influenza virus could block the virus entry into the host cells, thereby resulting in inhibition of the virus propagation. These Pseudomonas-derived lectins would be protential and attractive antiviral agents targeting glycoproteins of enveloped viruses including influenza virus.

A Novel High-Mannose Specific Lectin from the Green Alga Halimeda renschii Exhibits a Potent Anti-Influenza Virus Activity through High-Affinity Binding to the Viral Hemagglutinin

“…As seen in Figure 3, the binding preference of HRL40 for the exposed (α1-3) Man residue was markedly severe among Type I lectin family, promising the utility of this lectin as a valuable tool in the fields of basic and applied glycomics. To be exact, HRL40 potently inhibited the entry of influenza virus (A/H3N2/Udorn/72) to NCI-H292 cells with ED 50 of 2.45 nM, which was the highest anti-influenza virus activity that we have ever examined for lectins [8,9,13,35]. In addition, the affinity constant (K D , 3.69 × 10 −11 M) of this lectin for the influenza virus envelope hemagglutinin was also remarkably high.…”

“…From the cDNA cloning of a cyanobacterial lectin, OAA, we presented that the genes coding Type I lectin proteins are widely distributed in lower organisms [6,12,29], including red algae and bacteria such as Myxococcus xanthus hemagglutinin (MBHA) [31], Pseudomonas fluorescens lectin (PFL) [32] and Burkholderia oklahomensis agglutinin (BOA) [33]. MBHA and PFL were confirmed to inhibit the HIV-infection in the host cells using their recombinants [34,35]. The Type I HM-specific lectins (the OAA family) consist of two or four tandem repeats of the conserved domain of 66-67 amino acids.…”

“…The stained plates were pictured with a gray scale. The color densities of the pictures were quantitated by densitometry with the NIH-ImageJ 1.48 v software (National Institutes of Health, Bethesda, MD, USA) as described elsewhere [35]. The infected cell cultures in the absence of lectin exhibited severe cytopathic effect, almost all cells on the wells were gone, in which percent of cell viability was shown as 0%.…”

Lectins engineered to favor a glycan-binding conformation have enhanced antiviral activity

“…Some classes of them are well-known high-mannose binding lectins (e.g., in the complement system, surfactant proteins A and D) (1,12,13). Since high-mannose glycans are predominant on viral surface proteins such as human immunodeficiency virus-1 (HIV-1) gp120 and influenza hemagglutinin (HA) protein, the antiviral activities of high-mannose binding lectins are well known (2,(14)(15)(16)(17). We previously reported that Oscillatoria agardhii agglutinin (OAA)-the family of lectins, although exogenous bacterial lectins unrelated to human C-type lectins, showed broad-spectrum antiviral activity against multiple strains of HIV and influenza virus with 50% inhibitory concentration (IC 50 ) in the nanomolar range (17)(18)(19).…”

“…We previously reported that Oscillatoria agardhii agglutinin (OAA)-the family of lectins, although exogenous bacterial lectins unrelated to human C-type lectins, showed broad-spectrum antiviral activity against multiple strains of HIV and influenza virus with 50% inhibitory concentration (IC 50 ) in the nanomolar range (17)(18)(19). The antiviral activity was inhibited by the addition of yeast mannan (17), indicating that binding of the lectin to high-mannose glycans is committed to the activity. Antiviral activities of high-mannose binding lectins against hepatitis C virus (20, 21), coronavirus (22)(23)(24), Ebola virus (25,26), Japanese encephalitis virus (27), and others have been reported.…”