Submitted to: American Association of Avian Pathologists
Publication Type: Abstract Only
Publication Acceptance Date: 2/13/2015
Publication Date: 7/10/2015
Citation: Kapczynski, D.R., Pantin Jackwood, M.J., Spackman, E., Suarez, D.L., Swayne, D.E. 2015. Identification of viral epitopes recognized by the immune system following vaccination and challenge with the H7N9 avian influenza virus from China [abstract]. American Association of Avian Pathologists. CDROM.
Technical Abstract: In March of 2013, the first cases of H7N9 influenza were reported in humans in China, and shortly thereafter the virus was confirmed from poultry in live bird markets. Since that time the virus has persisted in both human and avian populations. The genetic composition of these H7N9 influenza viruses is of avian origin and of low pathogenicity in poultry. In response to the outbreak, vaccine efficacy trials were recently performed to determine if inactivated H7N9 vaccine could increase resistance of birds to clinical disease and shedding of virus. A homologous H7N9 vaccine was formulated into an inactivated emulsion and injected at various doses into 3 week old specific pathogen free (SPF) birds. Birds were challenged at 6 weeks of age with 10^8 EID50 per bird, delivered via intranasal route. Sham vaccinated birds demonstrated 10% mortality and reduction in weight gain. In contrast, vaccinated groups demonstrated improved weight gain compared to sham vaccinated birds. Specific regions of the virus that induce antibodies were discovered following analysis of specific linear epitopes of the hemagglutinin (HA) protein. Peptides produced to these epitopes resulted in increased virus-neutralization titers but not hemagglutinin-inhibition titers. These results suggest that linear epitopes to the HA protein contribute to protection following vaccination and challenge of poultry.