SULFATIDE BINDS TO HUMAN AND ANIMAL INFLUENZA-A VIRUSES, AND INHIBITSTHE VIRAL-INFECTION

We found, by using a virus overlay assay, that influenza A virus isola tes bind to sulphatide (HSO3-Gal beta 1 --> 1'Cer), which has no siali c acid residue, and that the infection of Madin-Darby canine kidney ce lls with the human influenza virus A/Memphis/1/71 (H3N2) is inhibited by sulphatide. A/Memphis/1/71 (H3N2) causes obvious haemagglutination and low-pH haemolysis of asialoerythrocytes reconstituted with sulphat ide. All influenza A virus isolates from the species of animals so far tested bound to sulphatide. The sulphatide-binding specificity of the isolates was different from the viral sialyl-linkage specificity. Inf luenza A virus isolates also bound to galactosyl ceramide (GalCer; Gal beta 1 --> 1'Cer), as well as sulphatide, in the virus overlay assays . In contrast. the influenza virus did not bind to N-deacyl, a derivat ive of sulphatide, glucosyl ceramide or the other neutral glycolipids tested. These results indicate that the linkage of galactose, or sulph ated galactose, to ceramide is important for viral binding.