IDENTIFICATION OF ANNEXIN 33-KDA IN CULTURED-CELLS AS A BINDING-PROTEIN OF INFLUENZA-VIRUSES

The binding of three influenza A and one influenza B virus strains to proteins of three continuously cultured cell lines was studied using p rotein overlay and immunostaining methods. The results obtained indica ted the presence of both sialic acid-dependent and -independent bindin g of the virus strains; virus binding to proteins in the molecular mas s range from about 40 to 103 kDa was dependent on sialic acid, whereas binding to the 33 kDa protein was independent of sialic acid. The 33 kDa binding protein was identified as annexin, a widely distributed no n-glycosylated calcium-dependent phospholipid-binding protein.