Binding of sulphatide to recombinant haemagglutinin of influenza A virus produced by a baculovirus protein expression system*

Association of sulphatide with influenza A virus (IAV) haemagglutinin (HA) delivered to the cell surface promotes progeny virus production. However, it is not known whether there is direct binding of HA to sulphatide. In this study, we found that recombinant HA, which was produced by a baculovirus protein expression system from the HA gene of A/duck/HK/313/4/78 (H5N3), bound to sulphatide in a dose-dependent manner and that the binding was inhibited by a specific antibody. Our results indicate that the recombinant HA is useful for elucidation of the binding domain of HA with sulphatide and for the development of new anti-IAV agents.