Influenza A virus haemagglutinin 5 (HA5 (sometimes H5 hemagglutinin))

Influenza A virus haemagglutinin 5 (HA5) is a subtype of the influenza viral hemagglutinin, a trimeric class I fusion glycoprotein located on the viral surface[1][3]. It plays a critical role in initiating infection by binding to sialic acid-containing receptors on the host cell surface and mediates fusion between the viral envelope and the host endosomal membrane following host cell uptake[1][3][6]. HA5 is responsible for virus entry, host specificity, and is the primary target for neutralizing antibodies generated by infection or vaccination[1][3]. The HA5 subtype, most notably found in H5N1 avian influenza, is of significant concern for zoonotic transmission and pandemic potential due to its role in cross-species infections and its tendency for antigenic variation, making it a focus for vaccine and therapeutic development[1][4].

Other names

Influenza hemagglutinin H5H5 hemagglutininHA5H5Influenza A hemagglutinin 5

Neutralizing antibodies prevent viral entry by blocking receptor binding or fusion - Fusion inhibitors disrupt conformational changes required for membrane fusion - Vaccines stimulate immune responses, especially antibody production against HA