Release

Release Once the viral envelope has separated from the cell membrane Influenza virus particles are actively released to complete the budding process. HA (hemagglutinin) anchors the virus to the cell by binding to sialic acid-containing receptors on the cell surface. The enzymatic activity of the neuraminidase (NA) protein removes the sialic acid and releases the virus from the host cell. NA activity is also required to remove sialic acid from the carbohydrates present on the viral glycoproteins to prevent the viral particles from aggregating.