Influenza hemagglutinin protein H7 subtype (HA (H7))

The **Influenza hemagglutinin protein H7 subtype** is a trimeric viral envelope glycoprotein and class I fusion protein present on the surface of influenza A viruses of the H7 subtype, including avian-origin strains such as H7N9 and H7N7[3][4]. It is the major viral antigen responsible for attaching the virus to host epithelial cells by binding sialic acid-containing glycan receptors and mediating the fusion of the viral and cellular membranes required for viral entry[2][3][4]. The hemagglutinin H7 protein contains distinct globular head and stem domains, with the head containing the receptor-binding site and the stem functioning in membrane fusion. H7 is a critical determinant of viral infectivity, host specificity, and antigenicity, and is a primary target for vaccine development, antibody therapies, and diagnostic assays. Neutralizing antibodies may target either the head or stem of HA, and broadly reactive monoclonal antibodies have been described[1]. The H7 hemagglutinin subtype has contributed to several significant human and animal influenza outbreaks due to its potential for antigenic shifts and zoonotic transmission[1][4].

Other names

Hemagglutinin H7HA H7H7 HAAvian influenza H7 hemagglutinin protein

Neutralizing antibodies bind hemagglutinin to block receptor binding and/or membrane fusion. Some antibodies disrupt the trimeric structure, preventing viral entry. Vaccines elicit anti-hemagglutinin antibodies for protective immunity.