Intranasal Immunization with a Recombinant Avian Paramyxovirus Serotypes 2 Vector-Based Vaccine Induces Protection against H9N2 Avian Influenza in Chicken

Even though the inactivated viral vaccine against H9N2 avian influenza viruses proved successful, it could not match the clinical demands of the live viral vectored vaccine. NDV can be utilized as a live vectored vaccine, but preexisting maternal antibodies reduce its effectiveness. Therefore, recombinant Avian Paramyxovirus-2 (APMV-2) expressed H9N2 HA was investigated as a live viral vector vaccine against the H9N2 avian influenza virus by intranasal vaccination. The rAPMV-2/HAs viruses were generated by the reverse genetics method. The biological characteristics and pathogenicity of the rAPMV-2/HAs were similar compared with the parental APMV-2-T4 virus. Experimental investigations on animals revealed that vaccination with rAPMV-2-NP-UTR-HA elicited robust H9N2-specific antibody responses and conferred complete immune protection to prevent viral shedding in the oropharyngeal and cloacal swabs from chickens challenged with the H9N2 virus. Therefore, rAPMV-2-NP-UTR-HA might be a good live viral vector vaccine candidate suitable for mass vaccination of commercial chickens in field conditions.

(MMR)