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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Exotic & Emerging Avian Viral Diseases Research » Research » Publications at this Location » Publication #309880

Title: The impact of H9N2 avian influenza virus vaccine antigenic variation on virus infectious dose in chickens

item WANG, YU - Orise Fellow
item Spackman, Erica

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/12/2014
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The H9 subtype of avian influenza virus is wide-spread in the areas of Asia and Middle East. Selection of effective vaccines that provide effective protection mainly depends on the antigenic match of the hemagglutinin protein (HA), between the vaccine and the field strain. To determine how the antigenic variations affect the vaccine efficacy, a vaccine-challenge study with different doses was conducted. Based on the 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 serial doses from 10^3 mean embryo infectious dose (50 percent EID) through 10^7 50 percent EID per bird. The control group of chickens was unvaccinated and challenged similarly. Pre-challenge sera were collected for hemagglutination inhibition assays to evaluate antibody titers. Virus shedding was quantitated by real-time reverse-transcription-PCR (rRT-PCR) of oral swabs. The mean infectious dose was calculated for each vaccine-challenge group. This study quantifies the differences in susceptibility to infection with H9 avian influenza virus based on antigenic variation between the vaccine and challenge virus.