Hemagglutinin stalk domain of group 1 Influenza A virus (HA stalk domain (group 1 IVA))

The hemagglutinin stalk domain of group 1 Influenza A viruses is a highly conserved region of the hemagglutinin surface glycoprotein, which is critical for mediating fusion between the viral envelope and host endosomal membranes during infection[1][2][3][4][6]. Unlike the immunodominant and variable HA head (receptor-binding) domain, the stalk (or stem) region evolves slowly, is intolerant to major sequence changes, and contains conserved epitopes recognized by broadly neutralizing antibodies, making it an attractive target for universal influenza vaccines and therapeutics[1][2][3]. HA is a homotrimeric protein, and the stalk region is composed mainly of the HA2 subunit, which undergoes a dramatic conformational rearrangement at low pH—triggering fusion of viral and host membranes[2][3][4]. Targeting the stalk domain is considered a promising approach for the development of broadly protective influenza interventions[1][2][3][6].

Other names

Influenza A hemagglutinin stem domain (group 1)HA stem domain (group 1)Group 1 Influenza A HA stalk

Inhibition of membrane fusion by preventing conformational change in the stalk domain Neutralization of viral entry into host cells