Fig. (2) Panels A-B showing types of heparan sulfate (HS) on cell surface: (Panel A) plain vanilla-type of unmodified HS and (Panel B) modified form of HS. The modified form of HS is represented by 3-O-sulfation by 3-OST-2, 3, 4, 5 and 6 isoforms. (Panel C): Multiple roles of HS during HSV-1 pathogenesis. This includes initial binding of HSV-1 glycoprotein B (gB) and C (gC) to plain-vanilla-type HS (upper panel), viral cell fusion in which modified from of HS, 3-OS HS, interacts with HSV-1 gD to mediate this process (middle panel) and finally both HS and modified HS are involved in viral spread from cell-to-cell in which four HSV-1 glycoprotein’s: gB, gD, gH and gL are involved (lower panel).