|Wang, Yue - Orise Fellow|
|Fouchier, Ron - Erasmus Medical Center|
|Davidson, Irit - Kimron Veterinary Institute|
Submitted to: International Symposium on Avian Influenza
Publication Type: Abstract Only
Publication Acceptance Date: 1/12/2015
Publication Date: N/A
Technical Abstract: The H9 subtype of avian influenza virus (AIV) is wide-spread in Asia and the Middle East. The efficacy of vaccines is enhanced by the antigenic match of the hemagglutinin protein (HA) between the vaccine and the field strain. To determine how antigenic variations affect the vaccine efficacy, specifically how the vaccine reduces susceptibility to infection, mean infectious dose studies were conducted with three H9N2 AIV isolates in chickens. Based on antigenic cartography, three isolates from Israel: the current vaccine virus and two other antigenic variants were selected for the studies. Specific-pathogen-free (SPF) chickens were vaccinated with each of the three isolates separately and challenged either against the same isolate or the other two antigenically heterologous isolates at 10-fold doses from 1,000 mean embryo infectious dose (EID50) through 10,000,000 EID50 per bird. The control group of chickens was unvaccinated and challenged similarly. Pre-challenge sera were collected and antibody to the vaccine and challenge viruses were determined with hemagglutination inhibition assay. Virus shedding was quantitated by real-time reverse-transcription-PCR of oral swabs collected 3 days post challenge. The mean infectious dose was calculated for each vaccine-challenge group. Initial results suggest that antigenic variation and the degree of antibody response from vaccination can affect infectious dose.