Influenza hemagglutinin stem (HA stem)

The influenza hemagglutinin stem is the highly conserved domain at the base of the trimeric hemagglutinin glycoprotein found on the surface of influenza viruses[1][4][6]. It anchors the protein to the viral membrane and plays a key role in mediating fusion of the viral envelope with the host cell membrane after virus entry via endocytosis[1][4][6]. Unlike the immunodominant head domain, the stem is less variable across influenza subtypes, making it an attractive target for broadly neutralizing antibodies and universal vaccine strategies[2][5][6]. Structural studies have shown the stem domain undergoes conformational changes critical for membrane fusion, a process targeted by novel therapeutics aiming to block infection at an early stage[1][2][4][6]. The development of drugs and vaccines focusing on the HA stem holds promise for influenza prevention and therapy due to its functional conservation and essential role in the viral life cycle[2][5][6].

Other names

Hemagglutinin stemHA stemHemagglutinin stalkHA stalk

Neutralization of viral entry by blocking membrane fusion step through binding the stem domain; Prevention of conformational change required for viral-host membrane fusion; Inhibition of viral infectivity by broadly neutralizing stem-directed antibodies.