Highly sulfated forms of heparin sulfate are involved in Japanese encephalitis virus infection

Japanese encephalitis virus (JEV) infects a broad range of cell types in vi tro, though little is known about the initial events of JEV infection. In t he present study, we found that highly sulfated glycosaminoglycans (GAGs) a re involved in infection of both neurovirulent (RP-9) and attenuated (RP-2m s) JEV strains. Competition experiments using highly sulfated GAGs, heparin and dextran sulfate, demonstrated an inhibition of JEV's attachment and su bsequent infection of BHK-21 cells. Treatment of target cells by a potent s ulfation inhibitor, sodium chlorate, greatly reduced viral binding ability as well as infection, suggesting a critical role of GAGs' sulfation status on the cellular surface in JEV infection. This phenomenon was confirmed by the manifestation of a distinct binding efficiency of JEV to the wild-type CHO cell line and its mutants with defects in GAG biosynthesis. We also dem onstrated the binding of JEV particles and virus envelope glycoprotein to i mmobilized heparin beads. Furthermore, the addition of heparin suppressed t he cytopathic effects induced by JEV infection in cultured cells. Our resul ts establish that the highly sulfated form of GAGs on cell surfaces plays a determining role in the early stage of in vitro JEV infection. (C) 2001 Ac ademic Press.