Hemagglutinin (HA) of Influenza A virus (H1N1) (HA)

Influenza A H1N1 hemagglutinin (HA) is a homotrimeric surface glycoprotein essential for the infectivity of the influenza A virus [2, 6]. It consists of two main subunits: HA1, which contains the receptor-binding site for host sialic acids, and HA2, which mediates the fusion of the viral envelope with the host endosomal membrane [6, 9]. As the primary antigen recognized by the host immune system, HA is the central component of most influenza vaccines, which function by inducing neutralizing antibodies that block viral entry [10, 16]. However, the protein's globular head is subject to frequent mutations (antigenic drift), requiring annual updates to seasonal vaccines to maintain efficacy [14, 16]. Therapeutic strategies targeting HA include monoclonal antibodies and small-molecule inhibitors that aim to prevent viral attachment or inhibit the conformational changes necessary for membrane fusion [3, 5].

Other names

H1N1 HAH1 hemagglutininInfluenza A virus hemagglutininHA1HA2Hemagglutinin glycoprotein

Induction of neutralizing antibodies that block viral attachment to sialic acid receptors or inhibit pH-dependent membrane fusion; direct inhibition of viral entry by small molecules or monoclonal antibodies.