Perspective of Influenza Research in Korea NIH

influenza virus (HPAIV) strain H5N1 has resulted in serious economic losses to the poultry industry, many countries including Vietnam have introduced mass vaccination of poultry with H5N1 virus vaccines. We found that eggs obtained from chicken farms and supermarkets in Vietnam contain H5N1-specific immunoglobulins (IgY) that provide protection against infections with HPAIV H5N1 and related H5N2 strains in mice. When administered intranasally before or after lethal infection with HPAIV H5N1, H5N1-specific IgY prevent disease or significantly reduce viral replication resulting in complete recovery from the disease, respectively. In addition, we generated H1N1 virusspecific IgY by immunization of hens with inactivated H1N1 A/PR/8/34 as a model virus for current pandemic H1N1/09 and found that such H1N1-specific IgY protect mice from lethal influenza virus infection. These results underscore the usefulness of recombinant Ad vectors encoding surface glycoprotein (HA) and conserved protein (M2e) and NS1 deleted viruses (DelNS1) as vaccine candidates for control of pre-pandemic H5N1 and newly emerging subtypes. Data on antiviral efficacy of IgY provide a proof-of-concept for the approach using virus-specific IgY as affordable, safe, and effective alternative for the control of influenza outbreaks, including the potential H5N1 and current H1N1 pandemic.