Влияние единичных аминокислотных замен в гемагглютинине вируса гриппа В/Флорида/04/2006 ямагатской эволюционной линии на антигенные и рецепторсвязывающие свойства

Influenza A and B viruses use sialylated oligosaccharide chains expressed on the surface of a host cell as the cell entry receptors. Type of the bond between sialic acid (SA) and neighboring galactose residue (Gal) is one of the main characteristics that define the type of receptor. Influenza viruses recognize SAα2-3Gal- or SAα2-6Gal-structures on the surface of the cells. The Yamagata-like virus strains are predominantly bound to α2,6-sialylated glycans, while Victoria-like strains are bound to both α2,3- and α2,6-sialylated glycans. However, the receptor-binding specificity of influenza B viruses has not been characterized enough. In this study, we selected escape mutants of influenza B/Florida/04/2006 strain (Yamagata-like lineage) using monoclonal antibodies (mAb) to hemagglutinin (HA). Analysis of the amino acid sequences of mAb-induced escape-mutants revealed the single amino acid substitutions 40Tyr→His, 85His→Tyr, 202Asn→Lys and 242Ser→Arg in 10F4-, 8Н11-, 8Н3- and 9А3-induced HA variants, correspondingly. It was shown that the single amino acid substitutions 202Asn→Lys and 242Ser→Arg alter the receptor-binding specificity of the influenza B virus. These findings are important for the understanding of the influence of individual amino acid residues in HA on the receptor-binding properties of influenza B Yamagata-like lineage viruses and allow us to predict the possible ways of their evolution.