Influenza A virus H5N1 antigens (H5N1 antigens)

Influenza A virus H5N1 antigens primarily comprise the surface glycoproteins hemagglutinin (HA) and neuraminidase (NA), which are the defining components of the H5N1 subtype [10, 13]. Hemagglutinin facilitates viral entry by binding to host cell sialic acid receptors (preferentially alpha-2,3-linked in avian strains) and mediating the fusion of viral and endosomal membranes [4, 15]. Neuraminidase functions as a sialidase, cleaving sialic acid residues to allow the release of progeny virions from infected cells and prevent viral aggregation [1, 16]. These antigens are the principal targets for the host immune response and are the primary focus of vaccine development to elicit neutralizing antibodies [3, 11]. Additionally, they serve as the targets for several antiviral classes: neuraminidase inhibitors (e.g., oseltamivir) block viral spread, while emerging hemagglutinin inhibitors aim to prevent the initial stages of infection [5, 8]. Due to the high mutation rate and potential for antigenic drift or shift, H5N1 antigens present a significant challenge for long-term therapeutic efficacy and global pandemic preparedness [12, 17].

Other names

H5N1 viral antigensAvian influenza A(H5N1) surface glycoproteinsH5N1 proteinsHemagglutinin (H5)Neuraminidase (N1)

Inhibition of viral neuraminidase to prevent the release of progeny virions; blockade of the M2 ion channel to inhibit viral uncoating; inhibition of hemagglutinin conformational changes to prevent membrane fusion; and vaccine-mediated induction of neutralizing antibodies targeting surface glycoproteins [1, 5, 13, 14].