Influenza A virus H7N7 hemagglutinin (HA)

Influenza A virus H7N7 hemagglutinin (HA) is a homotrimeric surface glycoprotein that mediates viral entry into host cells (UniProtKB - P03466). It functions by binding to alpha-2,3 or alpha-2,6-linked sialic acid receptors on the host cell surface, which triggers receptor-mediated endocytosis (Skehel & Wiley, 2000). Within the acidic environment of the endosome, HA undergoes a massive irreversible conformational change that facilitates the fusion of the viral envelope with the endosomal membrane, releasing the viral ribonucleoproteins into the cytoplasm (Hamilton et al., 2012). The H7N7 subtype is particularly noted for its high pathogenicity in avian species and its ability to cause severe respiratory disease and conjunctivitis in humans during zoonotic outbreaks (CDC, 2023). As the primary target of the host's neutralizing antibody response, HA is the central component of influenza vaccines (WHO, 2021). However, the high rate of antigenic drift in the HA head domain poses a significant challenge for long-term vaccine efficacy and therapeutic intervention (Boon et al., 2014).

Other names

HemagglutininH7 HASurface glycoprotein HAHA1/HA2

Inhibition of viral attachment to host cell sialic acid receptors and prevention of pH-dependent membrane fusion within the endosome (Blaising et al., 2014).