Animal viruses promote the entry of polysaccharides with antiviral activity into cells.

Charged polysaccharides such as heparin and carrageenan show potent antiviral activity in cultured cells. Labelled [3H]heparin binds to several virion particles as evidenced by Sepharose 6B chromatography. This binding is inhibited by carrageenan. The complex [3H]heparin-HSV1 virions is able to enter cells. Thus, almost no entry of [3H]heparin is observed in control HeLa cells, whereas in the presence of HSV1 or poliovirus the amount of radioactivity internalized is enhanced. This internalization is inhibited by carrageenan, suggesting that these two sulphated polysaccharides bind to the same sites on virion particles and may share a similar antiviral mechanism of action.