Influenza A H7N9 viral antigen (H7N9 antigen)

**Influenza A H7N9 viral antigen** refers collectively to the surface proteins—**hemagglutinin (HA)** and **neuraminidase (NA)**—of the H7N9 subtype of Influenza A virus, a zoonotic, avian-origin strain associated with significant human infection and mortality. The HA protein mediates viral entry by binding to sialic acid on host cells and facilitating membrane fusion, while NA cleaves sialic acids to enable viral egress[1][4]. These antigens, and especially the HA head and stem domains and the NA active site, are principal targets for the host immune response and for therapeutic agents, including monoclonal antibodies (e.g., H7-235) and neuraminidase inhibitors (oseltamivir, zanamivir, peramivir)[2][4][5]. H7N9 HA and NA proteins are the basis for most diagnostic, prophylactic, and therapeutic strategies against this virus, but they display antigenic diversity that can challenge vaccine and drug efficacy[3][5]. Notably, anti-HA antibodies correlate with protection, but protective immunity is usually limited to closely related H7/H15 subtypes, and antigenic drift can lead to immune escape[1][3][5].

Other names

H7N9 influenza antigenH7N9 hemagglutinin (HA)H7N9 neuraminidase (NA)Avian influenza A (H7N9) antigen

Inhibition of neuraminidase enzymatic activity (prevents viral release, oseltamivir, zanamivir, peramivir)[4]; Neutralization of hemagglutinin (blocks receptor binding or membrane fusion, anti-HA antibodies)[1][2][5]; Inhibition of hemagglutination (prevents viral attachment to host)[2]; Disruption of viral entry and antigenic drift/escape prevention (anti-HA antibodies)[5]