الفهرس 
AbstractOnly 14 pages are availabe for public view
 |  | from | 190 |  |  |
| | | from | 190 | | |
Abstract
HA is a critical determinant of the pathogenicity of avian influenza viruses . The HA proteins of highly pathogenic H5 and H7 viruses contain multiple basic amino acids at the cleavage site that are recognized by ubiquitous proteases but low patgogenic virus contain a single arginine resdue at the HA cleavage site that are recognized by trypsin - like protease found generally at epithelial cell surfaces.