WSS45, a sulfated α-D-glucan, strongly interferes with Dengue 2 virus infection in vitro

Aim: To investigate the mode of action of WSS45, one sulfated derivative of an alpha-D-glucan from the Gastrodia elata Bl, on the multiplication cycle of dengue virus serotype 2 (DV2), including initial infection and intracellular replication. Methods: Virus multiplication in BHK cells were monitored by qRT-PCR, plaque reduction assay, and flow cytometry. Initial virus infection was dissected into adsorption and penetration steps by converting temperature and treating by acid glycine. Surface bound virions were detected by immunofluorescence staining for Evelope protein. Results: WSS45 effectively inhibited DV2 infection in BHK cells with an EC50 value of 0.68 +/- 0.17 mu g/mL, mainly interfered with virus adsorption, in a very early stage of the virus cycle. However, WSS45 showed no viricidal effect. Moreover, WSS45 could increase the detaching of virus from cell surface in BHK cell line. Conclusion: WSS45 exerted potent inhibitory effect on DV2 through interfering with the interaction between viruses and targeted cells. This activity was related to its molecular size.