Influenza A virus H5N1 hemagglutinin (H5 HA) (H5 HA)

Influenza A virus H5N1 hemagglutinin (HA) is the primary surface glycoprotein of the highly pathogenic avian influenza virus, playing a fundamental role in viral infectivity and host range determination [3, 11]. It mediates the initial stages of infection by binding to sialic acid receptors on host cell membranes—specifically alpha-2,3-linked sialic acids common in avian species—and subsequently facilitating the fusion of the viral envelope with the host endosomal membrane [8, 16]. As the primary antigen recognized by the host immune system, HA is the central focus of vaccine development, where the goal is to induce neutralizing antibodies that block these critical entry steps [2, 12]. The protein is a trimer composed of two subunits: HA1, which contains the variable receptor-binding domain, and HA2, which contains the more conserved fusion peptide and stalk region [5, 8]. Because of the virus's high mutation rate, HA undergoes frequent antigenic drift, which can lead}

Other names

H5N1 hemagglutininHemagglutinin H5HA5Avian influenza H5N1 hemagglutininH5N1 HA

Induction of neutralizing antibodies that bind to the hemagglutinin protein, thereby blocking viral attachment to host sialic acid receptors and inhibiting membrane fusion [2, 6, 12].