Submitted to: Clinical and Vaccine Immunology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/5/2006
Publication Date: 3/6/2006
Citation: Lee, C.W., Senne, D.A., Suarez, D.L. 2006. Development and application of reference antisera against 15 hemagglutinin subtypes of influenza virus by DNA vaccination of chickens. Clinical and Vaccine Immunology. p. 395-402. Interpretive Summary: Avian influenza virus is an important disease for poultry, including chickens and turkeys. The virus is extremely variable, particularly in the surface proteins, with 16 different distinct forms of the hemagglutinin protein, called subtypes, having been described. It is important to characterize any influenza virus based on the hemagglutinin subtype, typically through tests using antibodies. Antibodies have to be developed for all 16 hemagglutinin subtypes to have a complete test. Currently, chickens have to be infected with 16 different types of live virus to do this testing. We have developed a new way to produce these antibodies using a new type of vaccine. This vaccine uses DNA grown in bacteria, so that live influenza virus does not have to be handled. The type of antibodies produced are also purer than antibodies produced from live virus vaccination, which makes the test easier to interpret. This procedure can aid diagnostic labs in their ability to diagnose avian influenza.
Technical Abstract: Reference antisera were produced against 15 influenza hemagglutinin (HA) subtypes using DNA vaccination to produce a high quality polyclonal serum to the HA protein without antibodies to other influenza viral proteins. The HA gene from each of 15 different HA subtypes of influenza virus was cloned into a eukaryotic expression vector and injected intramuscularly, together with a cationic lipid, into three- to four-week-old specific pathogen free chickens. Birds were boostered twice at 4-week intervals after the initial injection, and in general, antibody titers increased after each boost. The antisera were successfully applied in the hemagglutination-inhibition test, which is the standard method for the classification of the HA subtypes of influenza virus. We also demonstrated the HA specificity of the antisera by Western blot and immuno-dot blot analysis. DNA vaccination also provides a safer alternative for the production of HA specific antibodies, since it is produced without the use of live virus.