Heparan sulfate
Heparin sulfate (HS) is known for its role as an attachment factor by many viruses to enter cells (B. H et al., 2003). Similar function of it in mediating the attachment/absorption of PEDV to its host cells has been suggested (CC et al., 2015), as confirmed by series of observations. First, HS is a complex polysaccharide located on the cell surface and extracellular matrix (S. S, WC, & JD, 2011). Second, Glycosaminoglycans (GAGs), composed of several covalently attached heparan sulfate (HS) chains, can provide sites for various viruses to bind to eukaryotic cells (B. H et al., 2003). Third, it has demonstrated that PEDV utilizes HS for its attachment to Vero cells, while pretreatment with heparin can inhibit PEDV infection. Moreover, both N- and O-linked sulfate groups within the heparan sulfate carbohydrate structure are functionally important for PEDV binding to cells (CC et al., 2015). Last, the binding ability of PEDV to Vero cells is reduced following the enzymatic removal of cell-surface heparan sulfate or the inhibition of heparan sulfate biosynthesis by treatment with chlorate (CC et al., 2015). These results robustly suggest that HS is at least an adsorbing factor for the infection of PEDV in Vero cells.