Patent ID: 8802110

Claim:
An engineered influenza hemagglutinin (HA) polypeptide that possesses at least 90% overall sequence identity with a reference HA polypeptide of SEQ ID NO: 1, which engineered HA polypeptide characterized in that its amino acid sequence includes: an amino acid residue (“Residue 137”) at a position corresponding to position 137 of SEQ ID NO:1 that is selected from the group consisting of arginine, lysine, glutamine, methionine and histidine; and an amino acid residue (“Residue 193”) at a position corresponding to position 193 of SEQ ID NO:1 that is selected from the group consisting of alanine, aspartic acid, glutamic acid, leucine, isoleucine, methionine, serine, threonine, cysteine, and valine; and an amino acid residue (“Residue 226”) at a position corresponding to position 226 of SEQ ID NO:1 that is selected from the group consisting of alanine, cysteine, glycine, isoleucine, leucine, methionine, phenylalanine, proline, tryptophan and valine; and an amino acid residue (“Residue 228”) at a position corresponding to position 228 of SEQ ID NO:1 that is selected from the group consisting of arginine, asparagine, aspartic acid, glutamic acid, glutamine, histidine, lysine, serine, glycine, threonine, and tyrosine.