Inhibition of influenza virus formation by a peptide that corresponds to sequences in the cytoplasmic domain of the hemagglutinin.

A decapeptide with a sequence corresponding to the cytoplasmic domain of the influenza virus hemagglutinin inhibited the release of virus particles and infectious virions when added to infected cultured cells for a 2-hr period during a one-cycle growth. Inhibition was dose-dependent in the range of 50 to 250 micrograms/ml. The peptide did not affect formation of intracellular virus-specific proteins or assembly of nucleocapsids and did not inhibit replication of two unrelated enveloped RNA viruses, Sindbis virus and vesicular stomatitis virus. Peptides of similar size but different in sequence were ineffective. We postulate that this peptide acts as a competitive inhibitor for virus-specific protein-protein interactions between the hemagglutinin and the matrix protein or nucleocapsid during virus assembly. These data offer an approach to the development of antiviral drugs based on virus specific activities.