Japanese encephalitis virus (JEV) infects a broad range of cell types in vitro, though little is known about the initial events of JEV
infection. In the present study, we found that highly sulfated
glycosaminoglycans (GAGs) are involved in
infection of both neurovirulent (RP-9) and attenuated (RP-2ms) JEV strains. Competition experiments using highly sulfated GAGs,
heparin and
dextran sulfate, demonstrated an inhibition of JEV's attachment and subsequent
infection of BHK-21 cells. Treatment of target cells by a potent sulfation 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 demonstrated the binding of JEV particles and virus envelope
glycoprotein to immobilized
heparin beads. Furthermore, the addition of
heparin suppressed the cytopathic effects induced by JEV
infection in cultured cells. Our results establish that the highly sulfated form of GAGs on cell surfaces plays a determining role in the early stage of in vitro JEV
infection.