Abstract
Influenza A virus consists of three membrane proteins : hemagglutinin (HA) and neuraminidase (NA) as major membrane viral proteins and M2 protein as a minor membrane protein. The HA mediates the receptor binding and membrane fusion and plays an important role during early phase of infection. Cleavability of the HA is a key determinant of pathogenicity of avian influenza virus and highly virulent new subtype virus A/H5N1 with cleavable HA caused human infections in Hong Kong in 1997. The NA contains the receptor destroying activity which mediates the release of virus from the surface of the infected cells and prevents from aggregation of newly released virus particles. M2 protein functions as a proton channel to release the viral genome into the cytoplasm from virus particles after the membrane fusion.
