Hemagglutinin Protein (Influenza Virus) (HA)

Hemagglutinin (HA) is a critical glycoprotein on the surface of influenza viruses, essential for viral infectivity. It mediates receptor binding to sialic acid-containing receptors on host cells and facilitates membrane fusion, enabling viral entry. As a major surface protein, it is a primary target of neutralizing antibodies and a key component of influenza vaccines. HA exhibits significant diversity and rapid evolution, necessitating constant monitoring and adaptation of vaccine strategies.

Other names

HA proteinInfluenza hemagglutininHemagglutinin-esterase fusion protein (HEF) - for Influenza C and D viruses

Neutralizing antibodies block receptor binding or prevent conformational change required for membrane fusion.