The invention relates to a process for inhibiting the infection of influenza viruses and a polypeptide or protein medicine used therein. More particularly, the invention involves a process for inhibiting the highly pathogenic avian influenza virus (such as H5N1 subtype) infection and human influenza virus (such as H1N1 subtype and H3N2 subtype) infection, as well as the polypeptide or protein involved therein, and a polynucleotide encoding the polypeptide or protein and a vector or host cell expressing said polypeptide or protein.
