Proposed model for ZF 3-<i>O</i>ST-4 mediated HSV-1 entry.

<p>Cell expressing unmodified heparan sulfate (HS) do allow viral binding but not viral entry (panel a), while cells expressing HS modifying enzymes 3-<i>O</i> sulfotransferases (3-<i>O</i>ST) such as ZF encoded 3-<i>O</i>ST-2 or 3-<i>O</i>ST-4 mediates both viral binding and entry (panel b). Pre-treatment of CHO-K1 cells expressing ZF encoded 3-<i>O</i>ST-4 with anti-3-<i>O</i>S HS (G2) peptide generated against human 3-<i>O</i>ST-3 binds to the sites on the modified HS used by HSV-1 and thereby prevents both viral binding as well as viral entry (panel c).