Development of a Nano-vaccine against a Wild Bird H6N2 Avian Influenza Virus

A DNA vaccine, pCAG-HAk, expressing the full-length haemagglutinin (HA) gene of avian influenza A/Eurasian coot/Western Australia/2727/1979 (H6N2) virus, together with a Kozak sequence, in a pCAGGS vector was formulated with a novel nanoparticle, Phema. Two intramuscular immunizations of layer chickens at 3-week intervals with different doses of a nano-vaccine as well as 100 μg pCAG-HAk failed to induce detectable haemagglutination-inhibition (HI) antibody. Following virus challenge, the pCAG-HAk vaccinated group did not show a statistically significant difference in frequency of virus shedding in both oropharyngeal and cloacal swabs from the naive control group. However, in comparison with the naive control group, the 100 μg nano-vaccine group did significantly reduce virus shedding from the oropharynx. Despite lack of a dose-sparing effect from the nano-vaccine, there was a dose-response effect. This pilot study indicated that Phema used as an adjuvant augmented the immune response induced by the pCAG-HAk construct.