Hemagglutinin is a glycoprotein found on the surface of influenza viruses. It plays a crucial role in the virus's ability to infect host cells. The protein's primary function is to bind to sialic acid receptors on the surface of target cells, facilitating viral entry. Hemagglutinin is composed of two main regions: the head and the stalk. The stalk, in particular, has garnered significant attention in recent years for its potential role in influenza epidemiology and vaccine development.
