Potent anti-respiratory syncytial virus activity of a cholestanol-sulfated tetrasaccharide conjugate

• Published in: Antiviral research 2012-01, Vol.93 (1), p.101-109
• Main Authors: Lundin, Anna, Bergström, Tomas, Andrighetti-Fröhner, Carla R., Bendrioua, Loubna, Ferro, Vito, Trybala, Edward
• Format: Article
• Language: English
• Subjects: Animals; Antibiotics. Antiinfectious agents. Antiparasitic agents; Antiviral Agents; Antiviral Agents - pharmacology; Biological and medical sciences; Cell Line; Cell Line, Tumor; Clinical Medicine; Dogs; drug effects; Human viral diseases; Humans; Infectious diseases; Klinisk medicin; Medical sciences; Microbial Sensitivity Tests; PG545; pharmacology; Pharmacology. Drug treatments; Respiratory syncytial virus; Respiratory Syncytial Viruses; Respiratory Syncytial Viruses - drug effects; Saponins; Saponins - pharmacology; Sulfated oligosaccharides; Tumor; Viral diseases; Viral diseases of the respiratory system and ent viral diseases; Virucidal activity
• ISSN: 0166-3542; 1872-9096; 1872-9096
• DOI: 10.1016/j.antiviral.2011.11.002

► We modified sulfated oligosaccharides by addition of cholestanol to reducing end. ► The modification improved anti-RS virus potency of native oligosaccharide. ► The compound showed virucidal activity against RS-virus. A number of different viruses including respiratory syncytial virus (RSV) initiate infection of cells by binding to cell surface glycosaminoglycans and sulfated oligo- and polysaccharide mimetics of these receptors exhibit potent antiviral activity in cultured cells. We investigated whether the introduction of different lipophilic groups to the reducing end of sulfated oligosaccharides would modulate their anti-RSV activity. Our results demonstrate that the cholestanol-conjugated tetrasaccharide (PG545) exhibited ∼5- to 16-fold enhanced anti-RSV activity in cultured cells compared with unmodified sulfated oligosaccharides. Furthermore, PG545 displayed virus-inactivating (virucidal) activity, a feature absent in sulfated oligosaccharides. To inhibit RSV infectivity PG545 had to be present during the initial steps of viral infection of cells. The anti-RSV activity of PG545 was due to both partial inhibition of the virus attachment to cells and a more profound interference with some post-attachment steps as PG545 efficiently neutralized infectivity of the cell-adsorbed virus. The anti-RSV activity of PG545 was reduced when tested in the presence of human nasal secretions. Serial passages of RSV in the presence of increasing concentrations of PG545 selected for weakly resistant viral variants that comprised the F168S and the P180S amino acid substitutions in the viral G protein. Altogether we identified a novel and potent inhibitor of RSV, which unlike sulfated oligo- and polysaccharide compounds, could irreversibly inactivate RSV infectivity.