Ostrich produce cross-reactive neutralization antibodies against pandemic influenza virus A/H1N1 following immunization with a seasonal influenza vaccine.

An outbreak of influenza in 2009 was found to be caused by a novel strain of influenza virus designated as pandemic influenza A/H1N1 2009. Vaccination with recent seasonal influenza vaccines induced little or no cross-reactive antibody response to the pandemic influenza virus A/H1N1 2009 in any age group in human populations. Accordingly, most people had low immunity against this pathogen, thus resulting in the worldwide spread of the infection to produce a so-called 'pandemic'. This report presents the important finding that ostrich eggs generate cross-reactive antibodies to the pandemic influenza virus A/H1N1 following immunization of female ostrich with a seasonal influenza vaccine. This simple method produced a large amount of antibodies against influenza viruses by one female ostrich. An enzyme-linked immunosorbent assay (ELISA) and immunocytochemistry indicated that the ostrich antibodies possessed strong cross-reactivity to the pandemic A/H1N1 as well as to the seasonal A/H1N1, A/H3N2 and B viruses. The hemaggregation activities of erythrocytes induced by this pandemic strain were also inhibited by the ostrich antibodies. In addition, the cytopathological effects of infection with a pandemic virus on MDCK cells were clearly inhibited in co-cultures with the ostrich antibodies, thereby indicating the neutralization of viral infectivity in the cells. In conclusion, cross-reactive neutralization antibodies against pandemic influenza virus A/H1N1 2009 were successfully generated in ostrich eggs produced by females immunized with seasonal influenza viral vaccine.

Development of neutralization antibodies against highly pathogenic H5N1 avian influenza virus using ostrich (Struthio camelus) yolk.

The rapid outbreak of the highly pathogenic H5N1 avian influenza virus and its transmission to humans have induced world-wide fears of a new influenza pandemic. The most effective method for the reduction of the impact of such a pandemic would be prophylaxis with a safe and effective vaccine, as well as anti-viral materials. In this study, we generated the specific antibodies 'immunoglobulin yolk (IgY)' from ostrich eggs immunized with a full-length glycosylated recombinant H5 protein of the strain H5N1/Vietnam/1203/2004. Using this simple method, abundant specific antibody (about 200 g) against H5 was successfully produced by one female ostrich in a year. The IgY from the immunized ostrich eggs had strong reactivity to the H5N1 virus as well as to H5 proteins. Furthermore, the antibodies strongly inhibited cytopathic effects in MDCK cells and prevented the death of an embryonated chick after a viral inoculation, indicating strong neutralization activity against H5N1 infections. These findings suggest that the neutralization antibody produced by the H5-immunized ostrich is suitable for industrial purposes, such as the development of antibody-binding filters, which can be applied to a mask or to air-conditioners to prevent the influenza pandemic through antigen-antibody reactions. Of note, the mortality rate of chicks inoculated with the H5N1 virus was dramatically decreased with antibody injection. This indicates that ostrich IgY is a potentially effective therapeutic modality for H5N1 infection.