Avian antibodies to combat potential H5N1 pandemic and seasonal influenza

Highly pathogenic avian influenza A virus (HPAIV) strain A/H5N1 with unprecedented spread through much of Asia and parts of Europe in poultry remains a serious threat to human health. Passive immunization (transfer of protective immunoglobulins) offers an alternative and/or additional strategy to prevent and cure influenza. Here, we report that virus-specific immunoglobulin Y (IgY) isolated from eggs of immunized hens provide protection in mice against lethal H5N1 virus infection by neutralization of the viruses in the lungs upon intranasal administration. Importantly, chicken eggs obtained from randomly selected supermarkets and farms in Vietnam, where mass poultry vaccination against A/H5N1 is mandatory, contain high levels of IgY specific for A/H5N1 virus. When administered before or after the infection, IgY prevented and significantly reduced replication and spread of HPAIV H5N1 and related H5N2 strains. Thus, the consumable eggs readily available in markets of countries that impose poultry vaccination against A/H5N1 could offer an enormous source of valuable biological material that provides protection against A/H5N1 virus with pandemic potential. The approach could be used to control seasonal influenza.