Antibody Recognition of the Influenza Virus Neuraminidase

Influenza virus neuraminidase (NA) was the first enzyme found to be an integral part of a virus and coded by the viral genome. It remains one of the best-characterized viral enzymes at the molecular level, although its role in viral infection is still not well understood. NA cleaves terminal N-acetyl neuraminic acid (sialic acid) from glycoconjugates on the cell surface. Because sialic acid is the receptor to which influenza virus hemagglutinin (HA) initially binds on the host cell, NA is a receptor-destroying enzyme. It allows virus to be released from the surface of infected cells and prevents self-aggregation by cleaving sialic acid from the complex carbohydrates on the HA (Palese et al. 1974; Basak et al. 1985). NA may also assist in virus spread and access to new cells by cleaving sialic acid from the mucins that overlie the epithelial cells of the respiratory tract. Although the relative importance of...