Heparin-binding activity of feline herpesvirus type 1 glycoproteins

Feline herpesvirus type 1 (FHV-1) possesses a very narrow host range, but the mechanism of its infection has not yet been analyzed. Heparan sulfate on the cell surface serves as a receptor for several herpesviruses. In this study, we determined that infection of FHV-1 is inhibited by addition of soluble heparin in cells cultures. Using heparin-affinity column, it was shown that FHV-1 gC is a major heparin-binding protein, and FHV-1 gB weakly binds to heparin, but FHV-1 gD does not. Furthermore, the FHV-1 gC expressed in insect cells can also bind to heparin despite of being immature glycosylation. Our results suggested that FHV-1 gC can bind to heparin as observed in other herpesviruses and that glycosylation of the gC does not affect its heparin-binding activity. In addition, mice immunized with the gC expressed in insect cells produced complement-dependent virus-neutralizing antibody.