Tuesday, August 3, 2010: 10:30 AM
Seacliff AB (Hyatt Regency San Francisco)
As the spectacle of avian influenza (AI) is unfolding, it is urgent to develop a new generation of AI vaccines that can be rapidly produced and mass administered into poultry. We have demonstrated that protective immunity against AI virus could be elicited in chickens by in ovo vaccination with a non-replicating human adenovirus (Ad) vector encoding an AI virus hemagglutinin (HA). Vaccinated chickens were protected against both H5N1 and H5N2 highly pathogenic AI virus challenges. This vaccine can be mass-administered using available robotic in ovo injectors; it is compatible with a DIVA (differentiation between infected and vaccinated animals) strategy of vaccination; and the intrinsic problems associated with embryonated eggs for vaccine production are eliminated by propagating Ad vectors in the well-characterized PER.C6 cell line.
In addition to mass immunization of poultry, we have also shown that intranasal administration of an Ad-vectored influenza vaccine could induce seroconversion in human volunteers without appreciable side effects, even in subjects with pre-existing Ad immunity. Mice and ferrets were well protected against infection by a lethal dose of an H5N1 AI virus following intranasal instillation of an Ad vector encoding a codon-optimized HA gene in a single-dose regimen.