Antibodies against swine influenza virus neutralize the pandemic influenza virus A/H1N1

The most effective method for the prevention of influenza infection would be prophylaxis with a safe and effective vaccine and anti-viral materials. After vaccination, neutralizing antibodies are generated by plasma cells following various immune responses, thus resulting in protection against an infectious agent expressing the same antigens. However, in the case of novel or unknown pathogens, the onset of immune responses is occasionally delayed, thus resulting in considerable morbidity and mortality. Antibodies are therefore considered to play an important role in preventing infectious diseases. Furthermore, antibodies are used for additional purposes, including diagnosis and immunotherapy. In the beginning of spring 2009, an outbreak of influenza in North America was caused by a novel strain of influenza virus, designated pandemic influenza A/H1N1 2009. Initially, most people had low immunity against this pathogen, resulting in the worldwide spread of the infection to produce a so-called ‘pandemic’. We herein report the generation of ‘immunoglobulin yolk (IgY)’ neutralizing antibodies against the pandemic influenza virus A/H1N1 from ostrich eggs immunized with a swine influenza virus vaccine strain. Using this simple method, a large amount of specific antibody against the influenza virus was produced by one female ostrich. An enzyme-linked immunosorbant assay and immunocytochemistry indicated that the IgY from the immunized ostrich eggs possessed strong cross-reactivity to the pandemic influenza virus A/H1N1 2009, as well as to the swine influenza virus. Moreover, the hemaggregation activities of the erythrocytes induced by pandemic influenza A/H1N1 virus were inhibited by the ostrich antibodies generated by swine virus immunization. In addition, the cytopathological effects on MDCK cells of infection with pandemic virus were clearly inhibited in co-cultures with the antibodies, indicating the neutralizing of viral infectivity in the cells. In conclusion, we have succeeded in the mass production of neutralizing antibodies against pandemic influenza virus A/H1N1 2009 using ostrich eggs immunized with swine influenza virus antigens. This enables the cost-effective production of effective antibodies, which could be applied to facial masks and air-conditioning filters in order to prevent populations from acquiring pandemic influenza virus A/H1N1.