Recombinant Influenza A Hemagglutinin protein (Active)

Supplementary information

This supplementary information is collated from multiple sources and compiled automatically.

Influenza A Hemagglutinin often called hemagglutinin or the HA protein is a glycoprotein found on the surface of the Influenza A virus. It plays a mechanical role in the viral entry by binding to sialic acid residues on host cells. This binding allows the virus to attach and initiate infection. Hemagglutinin is known for its significant molecular mass of approximately 75 kDa. It expresses in various strains of the Influenza A virus including the Hong Kong strain and A/California/07/2009. It is an important component in determining the virus's ability to infect different host species.

Biological function summary

The HA protein functions in a critical step of the viral life cycle called fusion. During the infection process hemagglutinin undergoes a structural change that facilitates the fusion of the viral envelope with the host cell membrane. This fusion process is essential to release the viral genome into the host cell. Hemagglutinin generally operates as part of a trimeric complex which enhances its ability to interact with host cell receptors. This interaction is vital for the virus to efficiently invade the host cells and propagate the infection throughout the host.

Pathways

Hemagglutinin plays an important role in the viral fusion pathway and the innate immune response pathway. It interacts with proteins like neuraminidase another surface protein of the influenza virus which assists in the release of progeny viruses from infected cells. During the fusion pathway HA's structural changes allow the viral and cellular membranes to merge a step necessary for the virus to establish infection. Its involvement in the immune response pathway also prompts the host immune system to recognize and respond to viral threats.

Hemagglutinin is closely associated with influenza a contagious respiratory illness caused by influenza viruses. Mutations or antigenic shifts in HA contribute to seasonal flu epidemics and pandemics. The HA protein is a significant target for antibodies because its alteration can lead to vaccine inefficacy. Additionally it is associated with immune escape mechanisms where structural changes reduce antibody recognition. Researchers often study the interaction of hemagglutinin and antibodies like those targeting neuraminidase as these interactions are important for developing effective vaccines and antiviral therapies.