Inhibition of influenza virus infection by minimized peptides which bind to hemagglutinin

Influenza virus hemagglutinin (HA) binds to sialylgalactose (Neu5Ac-Gal) structure on host cells at the first step of infection. The peptide drugs are able to block the virus-sugar interaction. In our previous study, the HA-binding pentadecapeptide has been obtained from a random phage-displayed peptide library. However, it is considered that all amino acid residues are not involved in the interaction with HA, because the size of sugarbinding pocket in HA is too small to fill with pentadecapeptide. In order to identify the active residues, several peptide fragments were prepared. Plaque assay indicated that a N-terminal fragment had a high inhibition activity for influenza virus infection than the corresponding original peptide. We finally identified minimized HA-binding peptide. Furthermore, we showed that stearyl peptide was suitable for aggregate formation that was essential for inhibition of influenza virus infection.